JP3257311B2 - Liquid crystal display panel and projection display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display panel and a projection display device.

[0002]

2. Description of the Related Art In recent years, a liquid crystal projection display device which obtains a large-screen display image by enlarging and projecting a display image of a small liquid crystal display panel with a projection lens or the like has attracted attention and has been actively researched and developed. The liquid crystal projection display device has the following features. (1) A large-screen display can be obtained even with a small liquid crystal display panel. (2) The same resolution as that of the direct view type can be obtained even with 1/3 of the number of images. (3) There is no problem of viewing angle which is a drawback of the direct-view type liquid crystal display panel. (4) Smaller and lighter than the cathode ray tube (hereinafter referred to as CRT) system.

Hereinafter, a conventional liquid crystal projection display device will be described with reference to the drawings. FIG. 13 is a configuration diagram of a conventional liquid crystal projection display device. In the drawings, components unnecessary for description, such as a field lens, are omitted. The same applies to the following drawings. 1
Reference numeral 31 denotes a light source including a halogen lamp, a concave mirror, and a condenser lens, 133 denotes a projection lens, 134 denotes a screen, and 132 denotes a liquid crystal display panel with a color filter.

FIG. 14 is a sectional view of the liquid crystal display panel with a color filter of FIG. In FIG. 14, reference numeral 141 denotes a pixel electrode 143, a thin film transistor (hereinafter, referred to as a TFT, not shown), and a source signal line 14.
An array substrate on which 4 and the like are formed, 142 is a counter electrode 145
And the like are formed on the opposite substrate. On the counter electrode 145, a mosaic color filter 146 including three primary colors of red (R), green (G) and blue (B) is formed.
The alignment film 14 is formed on the color filter and the pixel electrode 143.
8a and 148b are formed, and the twisted nematic (T
N) An alignment process is performed so that the liquid crystal 147 is homogeneously aligned, and the array substrate 141 and the counter substrate 142 are aligned.
The orientation processing is performed so that the directions are different by about 90 degrees. As a result, the TN liquid crystal 147 has the liquid crystal molecule major axis direction parallel to the substrate, and is oriented in a state of being twisted by 90 degrees between the upper and lower substrates. Usually, the liquid crystal used for the TN liquid crystal panel has a positive dielectric constant.

FIG. 15 is a layout diagram of the three primary colors R, G, and B of the color filter. As for the color filter, one third of the color filters are R color, one third is G color,
The remaining 1/3 is the B color and is formed in a delta arrangement.

Light emitted from the light source 131 is collected by a concave mirror and a condenser lens, becomes parallel light, and enters the liquid crystal display panel 132. The light is converted into linearly polarized light by a polarizing film (not shown) disposed on the incident light side of the liquid crystal display panel 132, and R, G,
Only each light of B color is transmitted. A voltage is applied to each pixel electrode 143 in accordance with a video signal, and an electric field is applied to the liquid crystal layer 147 on the pixel electrode 143, so that incident light is modulated. The modulated light passes through a polarizing film (not shown) arranged on the emission side according to the degree of modulation, is condensed by the projection lens 133, and is enlarged and projected on the screen 134.

Next, the drive circuit system will be described. FIG. 16 is an explanatory diagram of a drive circuit system. R ₁ and R ₂ are resistors,
Q is a transistor, and constitutes a phase division circuit for generating positive and negative video signals of the video signal input to the base terminal by the resistors R ₁ and R ₂ and the transistor Q. 162a, 162b and 162c are output switching circuits for applying an AC video signal of which polarity is inverted for each field to the liquid crystal display panel 161.

Each video signal R, G, B is gain-adjusted to a predetermined value, and is input to a phase division circuit. The video signal is generated from two video signals of a positive polarity and a negative polarity by a phase division circuit, and is input to the next output switching circuit 162. The output switching circuit 162 performs timing adjustment and the like, and applies a video signal to the liquid crystal display panel 161 from an output terminal.
At this time, the polarity of the signal voltage applied to each pixel is applied with the polarity inverted for each field. The reason why the polarity of the voltage is switched in this way is to drive the liquid crystal by alternating current and prevent the liquid crystal from being decomposed and deteriorated. In a liquid crystal display panel, a source drive IC (not shown) is operated by a control circuit (not shown).
Synchronization with a gate drive IC (not shown) and an image are displayed on a liquid crystal panel.

[0009]

A conventional liquid crystal projection display device uses light emitted from a light source as linearly polarized light by a polarizing plate. That is, P-polarized light or S-polarized light
The polarized light is extracted, and the light is modulated by the liquid crystal display panel. Therefore, the unused polarized light is absorbed by the polarizing plate. The absorbed light heats the polarizing plate and also heats the polarizing plate itself or the liquid crystal display panel, thereby deteriorating the polarizing plate and the panel. Further, since only P- or S-polarized light is used, the light use efficiency is poor, and a high-luminance image cannot be displayed.

[0010] The liquid crystal display panel is formed with color filters of R, G and B colors. Taking a liquid crystal display panel having 90,000 pixels as an example, if each pixel is separated into R, G, and B colors, there are only 30,000 pixels each, and the resolution of the image is extremely poor. Therefore, even if subtitles of a movie or the like are displayed, they may not even be readable. In addition, flicker due to flicker is likely to be displayed. The image display in which flicker has occurred is not enduring.

A liquid crystal display panel has tens of thousands of pixels, and each of the pixels has a TFT formed thereon. It is difficult to form all of the TFTs without defects. Defective TFTs do not display images, and thus degrade image quality. In addition, when the number of defects is large or when there is a serious defect, the liquid crystal projection display device becomes defective.

The TN liquid crystal display panel has a dependency on the incident angle of light. When the spread angle of the light incident on the display panel increases, the contrast of the displayed image decreases. Therefore, when the TN liquid crystal display panel is used as a light valve of a projection display device, when the divergence angle of light incident on the panel is increased in an attempt to brighten the projected image, the contrast of the displayed image rapidly decreases. is there.

[0013]

In order to solve the above-mentioned problems, a display panel of the present invention employs a PD liquid crystal as a light modulation layer and performs light modulation as a change in a light scattering state. The color filter is formed on the pixel electrode. Preferably, the signal line is covered with the color filter to shield lines of electric force from the signal line. Further, the signal line may be covered with a low dielectric material.

A thin film that absorbs ultraviolet light is formed on the counter electrode in accordance with the shape of the pixel. When a PD liquid crystal panel is manufactured, ultraviolet light is applied to each of the red (R), green (G), and blue (B) pixels. Are made different. Therefore, the average particle diameter of the water-drop liquid crystal and the like are different for each of the R, G, and B pixels.

When polarized light is incident on the display panel of the present invention, the pixel electrodes are arranged in a matrix in the column direction and the row direction. When a voltage of the same polarity is applied in the column direction, it is made to coincide with the polarization direction (polarization axis) of the polarized light in the row direction. When a voltage of the same polarity is applied in the row direction, the polarization direction (polarization axis) of the polarized light is matched in the column direction.

When the display panel of the present invention is used as a reflection type display panel, a dielectric thin film is formed on at least one surface of the counter electrode, and the counter electrode and the dielectric thin film are formed to a predetermined optical thickness. By doing so, an antireflection film is formed.

Furthermore, a thick transparent substrate or a concave lens is disposed on the counter substrate or the like, and the above-mentioned members prevent the generation of secondary scattered light and improve the display contrast.

In the projection display device of the present invention, a PD liquid crystal panel is attached to a polarizing beam splitter (PBS) or a prism such as a dichroic prism. An optical coupling layer is used for attachment. That is, P
The D liquid crystal panel and the prism are optically connected. Further, a light absorbing film such as a black paint is applied to an ineffective area of the prism (mainly an area other than a light incident surface and a light incident / exit surface to the PD liquid crystal panel).

In particular, when the projection type display device of the present invention is of a reflection type, it is configured as shown in FIG. That is,
A plane including a first optical axis radiated from the lamp and incident on the PD liquid crystal panel, a second optical axis reflected by the PD liquid crystal panel and incident on the projection lens, and a center normal to the PD liquid crystal panel; A plane including the center normal line of the light separating surface of the prism is substantially orthogonal to each other.

Further, a projection type display device according to a second aspect of the present invention comprises:
The first PD liquid crystal panel and the second PD liquid crystal panel are optically connected to the PBS via an optical coupling layer. Preferably the PD light incident surface or the light exit reflecting surface of the liquid crystal panel, pasting a transparent substrate or a concave lens.

A first optical image from the first PD liquid crystal panel and a second optical image from the second PD liquid crystal panel are superimposed and projected at substantially the same position and enlarged and projected. The PD liquid crystal panel is R,
It has color filters of three primary colors of G and B, and preferably, the optical images of the first and second PD liquid crystal panels are projected with a shift of substantially one pixel.

[0022]

In the PD liquid crystal panel, lines of electric force are generated between the pixel electrode and the signal lines, and liquid crystal molecules are aligned with the lines of electric force, causing light leakage from the periphery of the pixel electrode. This is because polarization dependence occurs. To prevent this, shield lines of electric force from signal lines. Therefore, in the display panel of the present invention, the signal lines are covered with a color filter or a low dielectric material.

As another method for preventing light leakage due to polarization dependence, it is only necessary to make the liquid crystal display panel to enter polarized light having no polarization dependence. In the projection display apparatus according to the second aspect of the present invention, PBS is used as the light separating means. Therefore, polarized light enters the PD liquid crystal display panel that modulates the light emitted from the PBS. The PD liquid crystal display panel may be arranged so that the polarization axis of the polarized light is incident on a side having no polarization dependence.

The occurrence of the polarization dependence also affects the driving method of the liquid crystal display panel. If the generation of lines of electric force from the signal lines is completely prevented, the lines of electric force between adjacent pixel electrodes
The liquid crystal molecules are aligned. In a driving method in which signals of the same polarity are applied in the column direction (column inversion driving), polarized light having the column direction as a polarization axis is easily transmitted. Therefore, the polarization axis (polarization direction) of the polarization means (polarization plate, PBS, etc.) may be set to the row direction. In addition, driving (H) for applying signals of the same polarity in the row direction
In the inversion driving method, polarized light having the polarization direction in the row direction is easily transmitted. Therefore, the polarization axis (polarization direction) of the polarization means may be the column direction.

In the case where the projection type display apparatus is of a reflection type using a reflection type display panel, there arises a problem that the reflectance of P-polarized light and that of S-polarized light are different on the light separating surface in the prism. To solve this problem, as shown in FIG. 29, the angle of the incident light incident on the light separating surface and the angle of the outgoing light emitted from the light separating surface are symmetric with respect to the optical axis. By arranging as described above, the spectral reflectances of the P-polarized light and the S-polarized light become the same, and the color purity of the projected image is improved.

If the projected images of the two PD liquid crystal panels are shifted by one pixel and projected one on top of the other, additive color mixing can be carried out. The resolution can be improved if the color mixing is performed appropriately. In addition, if the polarities of the pixels at the superimposed positions are set to opposite polarities, flicker can be prevented.

If the projection display device has only one PD liquid crystal panel and the PD liquid crystal panel has a pixel defect,
The projected image is also displayed as a defect. However, since the projection display apparatus has two PD liquid crystal panels as in the present invention and the probability of occurrence of defects in both superimposed pixels is extremely low, defective pixels are hardly recognized.

[0028]

First, P-polarized light and S-polarized light will be described later with reference to FIG. 36 because they will be used later. P polarized light 3
Reference numeral 68 denotes light oscillating (oscillation direction 363) on a surface 368 including a normal line 362 of the light separation surface 366 of the dichroic mirror (light separation means having a light separation surface 366) 364 and a traveling direction of the incident light beam 361. . In addition, the S-polarized light means the P
The light vibrates in a direction perpendicular to the polarization vibration direction 363. The polarization direction 369 (polarization axis) of the polarizing means such as a polarizing plate refers to a direction in which polarized light is most easily transmitted.

Hereinafter, a display panel of the present invention used as a light valve of the projection display device of the present invention will be described with reference to the drawings.

FIG. 7 is a sectional view of a PD display panel according to the present invention. However, the optical coupling layer 42a is formed on the prism 14 or the like.
Indicates a state of optical connection. Each drawing is drawn as a model for easy explanation or easy understanding. Therefore, the physical thickness or shape in the drawings does not always match the actual display panel.
Parts unnecessary for the description are omitted.

The counter substrate 142 and the array substrate 141 are glass substrates, the thickness is 1.1 mm, and the refractive index n of the glass substrate is 1.52. Array substrate 141
The pixel electrode 143 made of ITO and the pixel electrode 1
TFT as a switching element for applying a signal to 43
71, various signal lines (not shown), and the like. As the switching element, in addition to the TFT, a two-terminal element such as a ring diode and MIM, or a varicap, a thyristor element, or the like may be used.

In this specification and claims, the substrate (for example, the substrates 141 and 142) is not limited to a glass substrate. For example, a plate made of a resin such as acrylic or polycarbonate may be used.
Further, a film or a sheet made of the resin or the like may be used.

A light shielding film 73 is formed on the TFT 71. The light shielding film 73 mainly prevents light scattered by the liquid crystal layer 121 from entering the semiconductor layer of the TFT 71. When light is incident on the semiconductor layer, a photoconductor phenomenon (hereinafter referred to as a photoconductor) occurs in which the TFT 71 does not turn off or the off-resistance of the TFT 71 decreases. As a material for forming the light shielding film 73, a material in which carbon is dispersed in an acrylic resin is exemplified. Moreover, various primary color pigment (red, green, blue, cyan, magenta, yellow dye) that optimally mixed, an insulating thin film such as SiO ₂ on TFT 71, serving as a light-shielding film 73 on the insulating film A method of forming a metal thin film by patterning is also exemplified. There is also a method of forming a light-shielding film by thickly depositing amorphous silicon. The TFT 71 preferably employs a staggered structure in which a semiconductor layer is formed below a gate.

In the PD display panel, it is preferable that the TFT is formed by polysilicon technology so that a photo transistor is hardly generated. The polysilicon technology includes a high-temperature polysilicon technology, which is a semiconductor technology for fabricating a normal IC, and a low-temperature polysilicon technology for forming an amorphous silicon film, which has been actively developed in recent years, and crystallizing the film. In particular, TFTs are manufactured using low-temperature polysilicon technology that can incorporate a drive circuit and can produce panels at low cost.
It is preferable to form 71 or the like. In the TFT 71 formed by the above technique, the occurrence of the photoconductor phenomenon is much less likely to occur than in the TFT 71 formed by the amorphous silicon technique. Therefore, it is most suitable for a PD liquid crystal panel that performs light modulation by scattering and transmission.

When the light-shielding film 73 is formed of a resin, any material may be used as the light-absorbing material contained in the resin as long as the material has high electrical insulation and does not adversely affect the liquid crystal layer 121. For example, a black pigment or a pigment in which a pigment is dispersed in a resin may be used, or gelatin or casein may be dyed with a black acidic dye like a color filter. As an example of the black pigment, a single fluoran pigment which becomes black may be used by coloring, or a black color mixture of a green pigment and a red pigment may be used.

The above materials are all black materials,
The case where the PD display panel of the present invention is used as a light valve of a projection display device is not limited to this.
The projection display device modulates three colors of light of R, G, and B with three PD display panels. The light shielding film 73 of the display panel that modulates the R light may absorb the R light. In other words, a light absorbing material for a color filter may be modified so as to be able to absorb a specific wavelength and used so as to obtain desired light absorbing characteristics. Basically, similarly to the above-described black absorbing material, a material in which a natural resin is dyed using a dye or a material in which a dye is dispersed in a synthetic resin can be used. The range of choice of the dye is wider than the black dye, and may be an appropriate one of azo dyes, anthraquinone dyes, phthalocyanine dyes, triphenylmethane dyes, and the like, or a combination of two or more thereof.
In addition, as a countermeasure against impurities in the light absorbing film 73, a countermeasure can be taken by removing an alkali metal in a coloring matter (pigment).

There are many materials for the black pigment that adversely affect the liquid crystal layer 121. Therefore, use is not preferable. Therefore,
As described above, a dye capable of absorbing a specific wavelength is used as the light absorbing thin film 7.
It is preferable to adopt as a dye containing 3.

Three PDs for R light, B light and G light
It is easy to adopt a projection display device using a display panel as a light valve. That is, the light-shielding film 73 may contain a dye that is complementary to the color of the light to be modulated. The complementary color relationship is, for example, yellow for B light. The light shielding film 73 colored yellow absorbs the B light. Therefore, the display panel that modulates the B light forms the yellow light shielding film 73.

If the light shielding film 73 is formed of resin, the liquid crystal layer 1
The adhesion between the substrate 21 and the array substrate 141 is improved. This is because the PD liquid crystal layer 121 contains a resin component. The liquid crystal layer 121 is likely to peel off, particularly from ITO forming the pixel electrode 143 and the like. If the light-shielding film 73 made of resin is formed on the TFT 71 or the like, the light-shielding film 73 becomes a buffer layer and does not peel off. From this point, it is preferable to employ a light-shielding film made of resin.

P is applied between the counter electrode 145 and the pixel electrode 143.
D liquid crystal 121 is interposed. The liquid crystal material used for the PD display panel of the present invention is preferably a nematic liquid crystal, a smectic liquid crystal, or a cholesteric liquid crystal, and may be a mixture containing one or more liquid crystal compounds or a substance other than the liquid crystal compound.

[0041] Note that among the liquid crystal materials mentioned above, a relatively large cyanobiphenyl nematic liquid crystal of the difference in the extraordinary refractive index n _e and ordinary index n _o or a stable fluorine-based change over time, chloro System nematic liquid crystal is preferred,
Among them, chloro nematic liquid crystals are most preferable because they have good scattering properties and are hardly changed with time.

As the polymer matrix material, a transparent polymer is preferable. As the polymer, a photo-curing type resin is used in view of easiness of the production process, separation from the liquid crystal phase, and the like. As a specific example, an ultraviolet curable acrylic resin is exemplified, and a resin containing an acrylic monomer or acrylic oligomer which is polymerized and cured by irradiation with ultraviolet light is particularly preferable. Above all, a photocurable acrylic resin having a fluorine group is preferable because the light modulation layer 17 having good scattering characteristics can be produced and a change with time hardly occurs.

The liquid crystal material preferably has an ordinary light refractive index n ₀ of 1.49 to 1.54, and particularly preferably has an ordinary light refractive index n ₀ of 1.50 to 1.53. It is preferable to use Further, it is preferable to use one having a refractive index difference Δn of 0.15 or more and 0.30 or less. As n ₀ and Δn increase, heat resistance and light resistance deteriorate. When n ₀ and Δn are small, heat resistance and light resistance are improved, but the scattering characteristics are reduced and the display contrast is not sufficient.

From the above, as a constituent material of the light modulating layer 121, a chlorinated nematic liquid crystal having an ordinary refractive index n ₀ of 1.50 to 1.53 and Δn of 0.15 to 0.30 is used. It is preferable to use a photocurable acrylic resin having a fluorine group as the resin material.

Examples of such a polymer-forming monomer include:
2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, neopentyl glycol acrylate, hexanediol diacrete, diethylene glycol diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol acrylate, and the like.

Examples of the oligomer or prepolymer include polyester acrylate, epoxy acrylate, and polyurethane acrylate.

Further, a polymerization initiator may be used in order to carry out the polymerization promptly. For example, 2-hydroxy-2
-Methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Merck), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1
-One ("Darocure 1116" manufactured by Merck), 1-vidroxycyclohexylphenylketone ("Irgacure 184" manufactured by Ciba-Gaiky), benzyl methyl ketal ("Irgacure 651" manufactured by Ciba-Geigy) and the like are listed. In addition, a chain transfer agent, a photosensitizer, a dye, a cross-linking agent and the like can be appropriately used as optional components.

The refractive index n _p when the resin material is cured
If, so as to substantially coincide with the crystal of the ordinary refractive index n _o.
Liquid crystal molecules are oriented in one direction when an electric field is applied to the liquid crystal layer, the refractive index of the liquid crystal layer is n _o. Therefore, the refractive index of the liquid crystal coincides with the refractive index n _{p of the} resin, and the liquid crystal layer is in a light transmitting state. Not a difference between the refractive index n _p and n _o is greater completely liquid crystal layer even when a voltage is applied to the liquid crystal layer and the transparent state, the display brightness is reduced. Refractive index difference between the refractive index n _p and n _o is preferably within 0.1, more within 0.05 are preferred.

Although the ratio of the liquid crystal material in the PD liquid crystal layer is not specified here, it is generally preferably about 30% by weight to 90% by weight, more preferably about 60% by weight to 85% by weight. When the content is less than 30% by weight, the amount of liquid crystal droplets is small, and the scattering effect is poor. When the content is 90% by weight or more, the polymer and the liquid crystal tend to be phase-separated into upper and lower layers, the ratio of the interface is reduced, and the scattering characteristics are reduced. The structure of the polymer-dispersed liquid crystal layer changes depending on the liquid crystal fraction. At about 60% by weight or less, liquid crystal droplets exist as independent droplets.
When the content is 60% by weight or more, a continuous layer is formed in which the polymer and the liquid crystal are intertwined with each other.

The average particle size of the liquid crystal droplets or the average pore size of the polymer network is 0.5 μm or more and 2.0 μm or less.
It is preferable to set the following. Above all, the thickness is preferably 0.8 μm or more and 1.5 μm or less. When the light modulated by the PD liquid crystal panel has a short wavelength (for example, B light), it is small, and when it is long wavelength (for example, R light), it is large. If the average particle diameter of the liquid crystal droplets or the average pore diameter of the polymer network is large, the voltage required for the transmission state decreases, but the scattering characteristics deteriorate. When it is small, the scattering characteristics are improved, but the voltage required for the transmission state is high.

When a PD liquid crystal is used in the PD liquid crystal panel of the present invention, the average particle diameter of the liquid crystal droplet or the average pore diameter of the polymer network of the PD liquid crystal panel that modulates blue light is determined by the PD liquid crystal that modulates red light The panel is smaller than that.

In FIG. 12A and FIG.
Is a water-drop liquid crystal, and 123 is a polymer. Pixel electrode 14
3 is connected to a TFT or the like, and a voltage is applied to the pixel electrode 143 by turning on / off the TFT. The light is modulated by changing the liquid crystal alignment direction of the liquid crystal on the water droplet 122 on the pixel electrode 143 by the voltage. As shown in FIG. 12A, when no voltage is applied (OFF), the liquid crystal molecules in each of the liquid crystal liquid droplets 122 are oriented in an irregular direction. In this state, a refractive index difference occurs between the polymer 123 and the liquid crystal, and the incident light is scattered. As shown in FIG. 12B, when a voltage is applied to the pixel electrode 143, the directions of the liquid crystal molecules are aligned. If the refractive index when the liquid crystal molecules are aligned in a certain direction is matched with the refractive index of the polymer 123 in advance, incident light is emitted from the array substrate 141 side without being scattered.

The PD liquid crystal according to the present invention is a liquid crystal in which the liquid crystal is dispersed in a resin in the form of water droplets (see FIG. 34), the resin becomes a sponge (polymer network), and the liquid crystal is filled between the sponges. And the like.
JP-A-208126 and JP-A-6-22085 also include a layered resin. In addition, as described in Japanese Patent Publication No. 3-52843, a liquid crystal in which a liquid crystal is sealed in a capsule-shaped storage medium is also included. Further, a liquid crystal or a resin 123 containing a dichroic or polychromatic dye is also included.

The thickness of the liquid crystal layer 121 is preferably in the range of 5 to 20 μm, more preferably 8 to 15 μm.
If the film thickness is small, the scattering characteristic is poor and contrast cannot be obtained. Conversely, if the film thickness is large, high voltage driving must be performed, and the gate drive circuit 316 and the source signal line 144 for generating a signal for turning on and off the TFT 71 on the gate signal line. It becomes difficult to design the source drive circuit 314 for applying a video signal.

The thickness of the liquid crystal layer 121 is controlled as shown in FIG.
Black glass beads 202 or black glass fibers as shown in 0), or black resin beads or black resin fibers are used. In particular, black glass beads or black glass fibers are preferable because they have very high light absorption and are hard, so that a small number of particles are scattered in the liquid crystal layer.

In the above description, the beads and the fibers are black, but the case where the PD liquid crystal panel of the present invention is used as a light valve of a projection display device is not limited to this. The projection display device modulates three colors of light of R, G, and B with three PD liquid crystal panels, respectively. Beads 19 used for PD liquid crystal panel that modulates R light
For example, R light may be absorbed. That is, the beads 202 containing a dye having a complementary color relationship to the color of the light to be modulated may be used.

The liquid crystal layer 121 scatters incident light (black display) when no voltage is applied. When transparent beads are used, even in a black display, light leakage occurs from the beads and the display contrast is reduced. When black glass beads or black glass fibers are used as in the PD liquid crystal panel of the present invention, light leakage does not occur and good display contrast can be realized.

The same can be said for the PD liquid crystal panel of the present invention.
That is, as shown in FIG.
And an insulating film 201 on at least one of the
It is effective to form As the insulating film 201, T
Alignment film such as polyimide used for N liquid crystal panel, etc.
Organic substances such as vinyl alcohol (PVA), SiO _Two
And the like. Preferably, in terms of adhesion and the like
And an organic substance such as polyimide.

The PD liquid crystal 121 has a relatively low specific resistance.
Therefore, the charge applied to the pixel electrode 143 may not be completely held for one field (1/30 or 1/60 second). If the liquid crystal layer 121 cannot be held,
Are not completely transparent, and the display luminance is reduced. A thin film made of an organic substance such as polyimide has a very high specific resistance.
Therefore, the charge retention can be improved by forming a thin film made of an organic material on the electrode. Therefore, high brightness display and high contrast display can be realized.

The insulating film 201 also has an effect of preventing the liquid crystal layer 121 from being separated from the electrode. This is because about half of the material constituting the liquid crystal layer 121 is an organic substance made of resin. Therefore, the insulating film 201 serves as an adhesive layer, and peeling of the substrates 141 and 142 from the liquid crystal layer 121 hardly occurs.

Further, when the insulating film 201 made of an organic material is formed, there is also an effect that the pore diameter of the polymer network of the liquid crystal layer 121 or the particle diameter of the droplet liquid crystal becomes substantially uniform. It is considered that even if an organic residue remains on the counter electrode 145, the organic residue is covered with the insulating film 201. The effect is better with PVA than with polyimide. This is probably because PVA has higher wettability than polyimide. However, various kinds of insulating films 201 were formed on the panel,
According to the results of the reliability (light resistance, heat resistance, etc.) tests performed, the polyimide used for the alignment film of the TN liquid crystal is good with almost no change over time. Therefore, it is preferable to use polyimide as the insulating film 201.

When the insulating film is formed of an organic material, the thickness is preferably in the range of 0.02 μm or more and 0.1 μm, and more preferably 0.03 μm or more and 0.08 μm or less.

Hereinafter, the polarization dependence generated in the liquid crystal layer 121 will be described with reference to FIG. Liquid crystal molecules 37
1 is the refractive index of the extraordinary refractive index n _e in the longitudinal direction, the minor axis direction represents the refractive index of the ordinary refractive index n _0. That is, there is an anisotropic refractive index. Also, the refractive index n _p of the polymer 123
Is approximately equal to the ordinary light refractive index n ₀ of the liquid crystal molecules.

FIG. 38 shows a state where a + voltage is applied to the pixel electrode 143 and a − voltage is applied to the source signal line 144. The electric lines of force 211 occur between the pixel electrode 143 and the source signal line 144. The electric field generated between the pixel electrode 143 and the signal line 144 is called a horizontal electric field. The liquid crystal molecules 371 are oriented along the lines of electric force 211 when the intensity of the lines of electric force (electric field intensity) is equal to or higher than a predetermined value (the rising voltage of the liquid crystal). Line of electric force 211 is a
The liquid crystal molecules 37 are generated in the direction a ′ and along the lines of electric force.
If 1 is oriented, the apparent refractive index of the liquid crystal layer 121 in the bb ′ direction becomes the ordinary light refractive index n ₀ . That is, since there is a relationship that n ₀ and the refractive index n _{p of the} polymer 123 are n ₀ ≒ n _p , b
The liquid crystal layer 121 can be considered to be in a transparent state for polarized light in the b ′ direction. On the other hand, the polarized light in the aa ′ direction is in a scattering state. Refractive index of the extraordinary refractive index n _e and the polymer and n _p is because regarded as state mingled.

Therefore, polarized light having the polarization axis in the aa 'direction is hardly transmitted, and polarized light having the polarization axis in the bb' direction is easily transmitted. That is, polarization dependence occurs. If the polarization dependency occurs, light leakage occurs from the peripheral portion of the pixel, and the display contrast of the PD liquid crystal panel is reduced.

As shown in FIG. 20, the source signal line 14
If a thin film made of a low dielectric material is formed on 4 (preferably a gate signal line), lines of electric force generated from the signal line can be shielded and a lateral electric field can be prevented. This is because a voltage drop is large in a low dielectric substance.

The low dielectric material is a material (low dielectric material) smaller than the relative permittivity of the liquid crystal of the liquid crystal layer 121. For example, inorganic materials such as SiO2 and SiNX, polymers 332 of the liquid crystal layer 17, resist, and organic materials such as polyvinyl alcohol (PVA) are exemplified.

It is preferable to use an organic material among the low dielectric materials, and it is particularly preferable to use a photosensitive resin used for the polymer 123 and the like. For example, an ultraviolet curable acrylic resin is exemplified. These resins are
In order to improve the adhesion to the liquid crystal layer 121, the liquid crystal layer 12
1 and the array substrate 141 are less likely to be separated. Further, it can be configured to be relatively thick. This is because a low dielectric film can be easily formed at a low cost and in a short time by a resin exposure and development process. As a matter of course,
As the thickness 73 of the low dielectric film increases, the shielding effect and the effect of preventing the lateral electric field increase.

The present invention is not limited to the low dielectric film 73. For example, as shown in FIG.
It may be 11. The low dielectric pillar 211 is a counter substrate 1
Preferably, it is formed on the 42 side. This is because the counter substrate 142 side is not formed except for the counter electrode 145, the substrate surface has smoothness, and there is no possibility that the TFT 71 or the like may be damaged by static electricity.

The effect of the low dielectric pillar 211 is high (see FIG. 2).
It is possible to completely eliminate the lateral electric field 212b shown in 1). Therefore, only the normal lines of electric force 212a can be generated, and light leakage from the peripheral portion of the pixel electrode 143 does not occur at all, and the display contrast can be improved.
Also, the low dielectric pillar 211 can be used as a means for regulating the thickness of the liquid crystal layer 121 such as the black beads 202. Therefore, there is no need to disperse the black beads 202 and the like, and the panel manufacturing process can be simplified, and furthermore, shadows due to the beads and the like do not occur.

It is preferable that the low dielectric pillar 211 in FIG. 21 and the low dielectric film 73 in FIG. 20 have a light shielding function. That is, the same material as the light shielding film 73 in FIG. 7 or a material obtained by adding a dye to a low dielectric material should be used. Even if a dye such as carbon is added to the low dielectric film, the relative dielectric constant hardly increases. The use of a light-shielding film can prevent the generation of a lateral electric field and can completely prevent light leakage from a peripheral portion of the pixel electrode 143.

When the lines of electric force generated from the gate and source signal lines are completely prevented, the state shown in FIG. 39 is reached. It should be noted that (FIG. 38) (FIG. 39) will be described later (FIG. 1).
0) (FIG. 11), “+” or “−” is displayed on the pixel electrode, but this merely indicates the polarity of the voltage applied to the pixel electrode 143. That is, the magnitude of the voltage applied to the pixel electrode is not considered. Further, FIG. 38 and FIG. 39 show that voltages of the same polarity are applied in the row direction. In addition, a method for driving a PD liquid crystal panel in which voltages of the same polarity are applied to two rows is shown.

Generally, as shown in FIG. 10, a driving method of applying voltages of the same polarity to the pixels 82 in the column direction is called column inversion driving. (FIG. 10 (a)) shows a voltage application state in the first field, and a second voltage following the first field.
In the field, voltages of opposite polarities are applied as shown in FIG. 10 (b). That is, the voltage polarity of the pixel changes in one field period.

As shown in FIG. 11, the pixels 82 in the row direction
The driving method of applying a voltage of the same polarity is called H inversion driving. (FIG. 11 (b)) shows a voltage application state in the first field. In the second field following the first field, voltages of opposite polarities are applied as shown in FIG. 11 (b).

As shown in FIG. 39, in the H inversion driving, b
A horizontal electric field in the direction b 'is generated. The liquid crystal molecules 371 are aligned along the horizontal electric field. The orientation facilitates transmission of polarized light in the aa ′ direction. In order to prevent polarized light in the aa 'direction, the polarization axis of polarized light emitted from the polarizing means and incident on the PD liquid crystal panel may be set to the bb' direction (column direction). On the other hand, in the column inversion driving, the polarization axis in the PD liquid crystal panel is aa ′ because the polarization in the bb ′ direction is easily transmitted.
Direction (row direction). This technical idea is important in a device that modulates polarization with a PD liquid crystal panel such as shown in FIG. This is because it is necessary to select and appropriately select the polarization axis of the P-polarized light or the S-polarized light incident on the PD liquid crystal panel and the driving method (H inversion driving, column inversion driving) of the PD liquid crystal panel. That is, in the column inversion drive, the polarization direction is set to the row direction, and in the H inversion drive, the polarization direction is set to the column direction.

The transmission type PD liquid crystal panel has been described above, but the technical concept described above may be a transmission type or a reflection type. Hereinafter, the reflection type P
The D liquid crystal panel will be briefly described with reference to FIG.

A reflection electrode 262 is formed on the TFT 71 via an insulating film 263. Reflective electrode 262 and TF
It is electrically connected to T71 at a connection portion 263. As a material of the insulating film 264, an organic material represented by polyimide or the like, or an inorganic material such as SiO ₂ or SiNx is used. The reflective electrode 262 has a surface formed of a thin film of Al. It may be formed using Cr or the like, but the reflectance is Al.
It is lower and harder, so that the periphery of the reflective electrode 262 is likely to be broken.

In the reflective PD liquid crystal panel shown in FIG. 26, a TFT 71 is formed below the reflective electrode 262. That is, the reflective electrode 262 has a function of a light-blocking film (BM) for preventing incident light scattered by the PD liquid crystal layer 121 from entering the semiconductor layer of the TFT 71 and a function of an electrode for applying a voltage to the liquid crystal layer 121. I have it together. The reflection electrode 262 is formed of a metal material, has a sufficient light shielding effect, and has a simple structure, so that cost reduction can be realized.

Source signal lines and the like (not shown) are formed on the array substrate 141. The reflective electrode 262 also has a function of shielding the lines of electric force radiated from the signal lines from reaching the liquid crystal layer 121. Accordingly, no image noise is generated due to the lines of electric force from the source signal line 144.

The reflection electrode 262 and the TFT 71 are connected to the connection 2
At 63, an electrical connection is established. In order to make a connection, it is necessary to deposit a metal thin film (reflection electrode) 262 to a thickness equal to or greater than the thickness of the insulating film 264. The thickness of the insulating film 264 is about 1 μm. Therefore, a step of 1 μm occurs in the connection part 263.
Further, since the thickness of the reflective electrode 262 is also 1 μm, a valley of 1 μm is formed between the adjacent reflective electrodes 262. PD
Since the liquid crystal panel uses PD liquid crystal, rubbing is not necessary, so there is no obstacle even if there is a step,
A liquid crystal panel can be manufactured with a high manufacturing yield.

The connection terminal portion 263 has a step of 1 μm. Further, the shape of the TFT 71 is patterned on the reflective electrode 262, and irregularities of about 1 μm are generated. Since the PD liquid crystal panel uses PD liquid crystal, light modulation is performed as a change in the scattering state. Therefore, the step and the TFT 71
The change of the liquid crystal film thickness by about 1 μm due to the unevenness hardly affects light modulation. In a liquid crystal panel such as a TN liquid crystal in which the optical rotation characteristic is applied to light modulation, the unevenness will be a fatal damage to light modulation.

The first dielectric thin film 261a, the ITO thin film 261b, and the second dielectric thin film 2
61c, which has a three-layer structure, and has an ITO thin film 261
The optical film thickness of b is λ / 2, and the optical film thicknesses of the first thin film 261a and the second thin film 261c are each λ / 4. Note that the ITO thin film 261b also functions as a counter electrode.

The first thin film 261a and the second thin film 26
The refractive index of 1c is desirably from 1.60 to 1.80.
For example, SiO, Al ₂ O ₃ , Y ₂ O ₃ , MgO, CeF
₃ , WO ₃ and PbF ₂ are exemplified. Also, among them, the first
When the thin film is made of SiO and the second thin film is made of Y ₂ O ₃ , an extremely excellent antireflection effect of 0.1% or less can be realized over the entire visible light region.

The optical thickness of the first and second dielectric thin films is λ / 4, and the optical thickness of the ITO thin film 261b is λ.
However, the optical thickness of the first and second dielectric thin films may be λ / 4, and the optical thickness of the ITO thin film may be λ / 4.

Further, in terms of the theory of the antireflection film, N
Is an odd number of 1 or more and M is an integer of 1 or more, the optical film thickness of the first and second dielectric thin films is (N · λ) / 4,
The optical film thickness of the ITO thin film 261b may be (N · λ) / 4. Alternatively, the optical thickness of the first and second dielectric thin films may be (N · λ) / 4, and the optical thickness of the ITO thin film may be (M · λ) / 2.

Further, one of the first and second dielectric thin films can be omitted. In that case, the performance as antireflection is somewhat reduced, but is often sufficient for practical use. Also in this case, the theory of anti-reflection can be applied.

According to the structure 261 described above, reflected light can be prevented without entering the liquid crystal layer 121, so that display contrast can be greatly improved.

The configuration of the above 261 is described in detail in Japanese Patent Application Laid-Open No. 5-109232, so please refer to it. The entire contents of the above publication should be applied to this specification. For example, as a configuration of a reflection type PD liquid crystal panel, there is a configuration shown in (FIG. 2) (FIG. 3) of the above publication. The characteristic diagrams are also shown in FIG.
8).

The reflection type liquid crystal panel has a thinner liquid crystal 121 with a good film thickness and good contrast and a high pixel aperture ratio as compared with the transmission type liquid crystal panel, so that high luminance display can be performed. In addition, since there is no obstacle on the back surface of the liquid crystal panel, panel cooling is easy. For example, forced air cooling and liquid cooling from the back surface can be easily performed, and a heat sink or the like can be attached to the back surface.

As is clear from FIGS. 7 and 26,
In the PD liquid crystal panel of the present invention, a black matrix (BM) is not formed on the opposing electrode 88 unlike the conventional TN display panel. In the PD liquid crystal panel of the present invention, there is basically no component formed by patterning on the counter electrodes 88 and 261. Therefore, in the step of bonding the opposing substrate 142 and the array substrate 141, the positioning of the opposing substrate 142 and the array substrate 141 is not required, and the manufacturing is facilitated. If a BM or the like is formed, it is necessary to align the BM on the order of μm so as to face the pixel electrodes (143, 262).

When the BM is formed, when the liquid crystal layer 121 of the PD liquid crystal panel is irradiated with ultraviolet light to cause phase separation between the resin component and the liquid crystal component of the liquid crystal layer, the BM blocks the ultraviolet light. , The resin under the BM remains uncured. The uncured resin impairs the stability of the PD liquid crystal panel and changes over time. Such a liquid crystal panel cannot be practically used as a light valve.

For light having a specific wavelength, the PD liquid crystal 1
The average particle size of the droplet-like liquid crystal at which the scattering characteristic of No. 21 is optimal,
There is an average pore size for the polymer network. In general, the longer the wavelength of light (red light), the larger the average particle diameter and the like of the liquid crystal droplets. Conversely, as the wavelength of the light is shorter (blue light), the scattering characteristics are improved by reducing the average particle diameter and the like of the liquid droplets. Therefore, it is preferable that the average particle diameter and the like of the display panel that modulates red light be larger than the average particle diameter and the like of the display panel that modulates blue light. To change the average particle diameter, after injecting the mixed solution and irradiating with ultraviolet light,
This can be achieved by varying the intensity of the ultraviolet light. When strong ultraviolet rays are irradiated in a short time, the average particle diameter and the like of the water-drop liquid crystal become small. Conversely, when the particles are irradiated with weak ultraviolet rays for a long time, the average particle size of the liquid droplets becomes large.

This problem is important when one PD liquid crystal panel modulates three colors of red, blue and green.
Specifically, this is a case where a mosaic color filter corresponding to the pixel is provided. Good display contrast cannot be expected unless the average particle diameter and the like are optimum for each pixel electrode. Therefore, irradiating the PD liquid crystal panel with ultraviolet rays uniformly to cause phase separation of the liquid crystal layer 121 does not provide very good results. This is because the average particle diameter and the like of the water-droplet liquid crystal cannot be set to optimal values according to the color of the color filter.

A configuration that solves the above problem is a configuration shown in FIG. The color filter 7 is provided on the pixel electrode 121.
2 are arranged. In order to facilitate the explanation, the color filter 72a is red and 72
It is assumed that b is green and 72c is blue.

On the opposite substrate 142, a dielectric thin film 221 is formed by patterning. The position and shape of the thin film 221 are made to substantially match the shape of the pixel electrode 121.

As the material of the dielectric thin film 221, TiO is used.
_TwoAlternatively, SiO is exemplified. TiO_TwoThe refractive index n of
2.3, the refractive index n of SiO is 1.7. Both materials are purple
It absorbs light of the wavelength in the outside line region and transmits visible light. However
The absorption wavelength band and the absorptance vary depending on the deposition conditions.
It is necessary to repeat the experiment and make settings.
You. As an example, experiments have shown that TiO_TwoIn the case of the membrane
Is 0.075 μm, the light absorptance is 350
40% for light with a wavelength of nm and 37 for light at 360 nm.
% At 370 nm, 16% at 380 nm
And hardly any visible light was absorbed. SiO is somewhat
Since it absorbs visible light, TiO _TwoIs better
Good.

The dielectric thin film 22 on the red filter 72a
1a is the thickest, the dielectric thin film 221b on the green filter 72b is thinner, and no dielectric thin film is formed on the blue filter 72c. Therefore, when polymerizing the mixed solution, the liquid crystal layer 1 is irradiated with ultraviolet rays from the direction A.
21c has the highest intensity of ultraviolet light,
21b, and the liquid crystal layer 121a becomes the weakest. The weaker the ultraviolet light, the larger the average particle diameter of the droplet liquid crystal 122 becomes. This is the same as increasing the average pore size of the polymer network.

Due to the difference in the ultraviolet ray absorptivity of the dielectric thin film 221 described above, the average particle diameter of the water-drop liquid crystal 122 in the liquid crystal layer 121 is as follows: liquid crystal layer 121a> liquid crystal layer 121b> liquid crystal layer 121c. The wavelength of the light that is optimally scattered and modulated with respect to the average particle diameter of the liquid crystal layer is substantially proportional to the wavelength. (FIG. 22)
By setting the average particle diameter to the optimum for the light of the color filter as described above, good display contrast can be obtained.

The average pore diameter of the polymer network or the average particle diameter of the water-droplet liquid crystal is 1.5 to 2.0 μm when the light to be modulated is red light, and 1.3 to 2.0 μm when the light to be modulated is green light.
When the thickness is 1.7 μm, and in the case of blue light, 1.0 to 1.5 μm, the display contrast is good. The average particle diameter is controlled by the thickness of the dielectric thin film 221.
Further, the film thickness is determined after sufficient experiments.

In FIG. 22 (FIG. 22), the light-shielding film 73 is formed on the source signal line 144 and the like. However, as shown in FIG.

In FIG. 22, the lateral electric field is prevented by forming the low dielectric film 73. However, as shown in FIG. 23, the source signal line 1 is connected to the color filter 72.
44, etc., and electromagnetic shielding may be performed. Since the source signal lines 144 and the like are only covered simultaneously when the color filters 72 are formed, it is easy to manufacture. The color filter 72 is a resin material and has a relatively low relative dielectric constant, and can have the same effect as the low dielectric film 73.

When irradiating the mixed solution with ultraviolet rays, if extremely intense light is radiated, the average particle diameter of the liquid crystal droplets becomes extremely small. If the voltage is extremely small, it will not be in a transmission state even when a voltage is applied. For example, the average particle size is 0.6 μm
In the following cases, the voltage at which the light enters the transmission state approaches 10 (V).

The liquid crystal layer on the pixel electrode 143 is normally 6 (V)
The transparent state is set at the following voltage. 10
If the specification is such that the transmission state occurs at (V), the scattering state occurs at 6 (V). In the scattering state, the display is black. Therefore,
An effect similar to the presence of a BM is obtained.

The structure shown in FIG. 25 employs a structure in which the liquid crystal layer 121 of the source signal line 144 and the like is constantly scattered as described above, and the BM is pseudo-BM. The dielectric thin film 2 is formed on the opposite electrode 88 facing the source signal line 144.
21 is not formed, and the counter electrode 8 facing the pixel electrode 143 is not formed.
8, a dielectric thin film 221 is formed. The dielectric thin film 221a corresponding to the red color filter 72a is the thickest, the dielectric thin film 221b corresponding to the green color filter 72b is next thinnest, and the dielectric thin film 221c corresponding to the blue color filter 72c is thinnest. Therefore, when irradiating the ultraviolet rays, the energy of the ultraviolet rays incident on the liquid crystal layer 121 is such that the liquid crystal layer 121a <the liquid crystal layer 121b <the liquid crystal layer 121c <the liquid crystal layer 121d. Due to the difference in the energy of the ultraviolet light, the size of the liquid crystal layer, such as the average particle diameter of the liquid crystal in the form of water droplets, is as follows. At this time, the liquid crystal layers 121a, 121b, 121c
Is to be in a transparent state at a voltage of 6 (V).
1d is set so as not to be in a transparent state unless it is close to 10 (V).

As described above (FIG. 25), if the average particle diameter of the liquid crystal on the source signal line 144 is made very small, the liquid crystal will not respond to the voltage application. The same effect as the case where the low dielectric pillar 211 is formed on the source signal line 144 or the like can be obtained. In other words, if the average particle size is very small, no response is made to the lateral electric field. Therefore, light leakage from the periphery of the pixel or the like is eliminated. Further, since the light is always in the scattering state, the same effect as when the BM is formed can be obtained.

In order to obtain a particle size changing structure in a reflection type PD liquid crystal panel, a configuration as shown in FIG. 27 may be adopted.
Since the structure of the transmissive liquid crystal panel shown in FIG. 24 (FIG. 24) and the like is adopted for the reflective type, no particular description will be required. Irradiation of ultraviolet rays may be performed from the A direction.

Hereinafter, the projection display device of the present invention will be described with reference to the drawings. First, specifications common to the projection display device of the present invention will be described. The following values or value ranges are particularly important for a projection display device using a display panel using a polymer-dispersed liquid crystal as a light modulation layer as a light valve.

In the projection display device of the present invention, from the viewpoint of improving the light utilization factor, if the panel effective display size (display area of the panel) is reduced, the F-number of the illumination light needs to be increased. If the panel effective display size d is increased, the F number of the illumination light can be reduced, and as a result, a bright large-screen display can be realized. However, when the panel effective display size increases, the system size of the projection display device increases, which is not preferable. Further, when the panel effective display size is reduced, the luminous flux per unit area incident on the display area of the panel increases, which is not preferable because the panel is heated.

When the luminance of the illuminant is fixed at 1.2 × 10 ⁸ (nt) in consideration of the lamp life, it is considered that the arc length and the power consumption of the lamp are approximately proportional. The efficiency of the metal halide lamp is 80 (lm / W). 50
The total luminous flux of the lamp of (W) is 4000 (lm), 100
The total luminous flux of the lamp of (W) is 8000 (lm), 150
The total luminous flux of the lamp of (W) is 12000 (lm).
There is a correlation between the arc length of the lamp and the lamp power consumption, and there is a correlation between the arc length and the F number.

In the projection type display device, the projected image is required to have a screen size of 40 inches or more, and a luminous flux of 300 to 400 (lm) or more in order to obtain a viewing angle and image brightness in a practical range. Therefore, the light utilization of the lamp is 4
%, A lamp of 100 (W) or more must be used. From this, the display contrast (C
Arc length 3 (mm) if only for obtaining good R)
Can be used, but a metal halide lamp of 100 (W) or more is required in order to obtain sufficient luminance of the projected image.

Further, if the panel effective display size is small, sufficient display luminance cannot be obtained. Assuming that the arc length is 5 (mm) and the effective F value of the illuminating light is 7, the panel effective display size needs to be about 3.5 inches. If the arc length is about 5 (mm) and the panel effective display size is slightly more than 2 inches, the effective F value of the illumination light is less than 5. In this case, display luminance is in a practical range, but good display contrast (CR) cannot be expected.

As a result of various experiments and examinations, the effective F of the illumination light was obtained.
When the value is 5 or more, display luminance in a practical range can be obtained. However, in order to obtain good display luminance and display contrast, appropriate power consumption and lamp life, the effective F value of the illumination light (= the effective F value of the projection light) is around 7, and the arc length of the lamp is 5 (mm). Before and after, it was necessary to use about 150 W for the lamp.

When the F-number of the projection lens is reduced, the screen luminous flux reaching the screen increases. Accordingly, the power consumption of the lamp must be increased. Further, when the power consumption of the lamp is increased from the viewpoint of extending the life of the lamp, the arc becomes longer when the arc luminance is considered to be constant. As a matter of course, the display contrast (CR) becomes worse as the F-number becomes smaller. Conversely, when the F-number of the projection optical system is increased, the display contrast increases, but the screen light flux decreases.

As a result of various experiments and examinations, the arc length of the lamp was set at 3 in order to obtain good display contrast.
(Mm) or more and 6 (mm) or less. Further, from the viewpoint of power consumption, it must be 250 (W) or less. And 100 (W) to obtain screen brightness
The above metal Harad lamp must be used. More preferably, the arc length should be 3 (mm) or more and 6 (mm) or less in consideration of screen brightness and display contrast.

The diagonal length of the effective display area of the panel must be 4.5 inches or less from the viewpoint of the system size.
Further, it must be 2 inches or more from the viewpoint of light use efficiency. Above all, in order to obtain a sufficient light focusing efficiency and to make the device compact, it is preferable that the thickness be 3 to 4 inches.

The F number of the projection lens, that is, the F number of the projection optical system in a broad sense, must be 5 or more in order to obtain a good contrast (CR). Also, it must be 9 or less to obtain sufficient screen brightness. Further, considering the arc length of the lamp described above, the F number must be 6 or more and 8 or less.

If the divergence angle (F number) of the illumination light does not substantially coincide with the converging angle (F number) of the projection lens, the light utilization rate decreases. This is because the restriction is imposed on the larger F number. The F-number of the illumination light of the projection display apparatus of the present invention and the F-number of the projection lens are made to match.

In the above description, for example, an arc length of a lamp of 5 mm means “substantially 5 mm”. Substantially 5 mm means that the arc length is 8 m
Even if m, the arc length is substantially 5 mm if the projection lens can collect only the light radiated from around 5 mm at the center of the arc, out of the light radiated from the arc. Similarly, the F number means an effective F number.
Even if the physical F number is 4, if the light passes only near the center of the pupil of the projection lens, the F number is naturally 4 or more.

FIG. 1 is a block diagram of an embodiment of the projection display apparatus of the present invention. The light source 11 includes a lamp 11b and a concave mirror 11a. Examples of the lamp 11b include a metal halide lamp, a xenon lamp, and a halogen lamp. The concave mirror 11a is made of glass and has a reflective surface on which a multilayer film that reflects visible light and transmits infrared light is deposited.

The filter 12 is formed by depositing a multilayer film on a glass substrate that transmits visible light and reflects infrared light and ultraviolet light. Hereinafter, the above-mentioned filter will be referred to as UVIR cut filter 1
Call it 2. The visible light included in the light emitted from the lamp 11b is reflected by the reflecting surface of the concave mirror 11a. Concave mirror 11
The reflected light emitted from a is a UVIR cut filter 12
As a result, infrared rays and ultraviolet rays are removed and emitted.

The visible light is reflected by the mirror 13a and enters the PBS 14 in the direction. The PBS is a cube-shaped polarizer in which slopes of a pair of right-angle prisms are bonded to each other, and a dielectric multilayer coating layer is formed on the slopes. The coating layer separates incident light into P-polarized light and S-polarized light. The coating layer is referred to as a light separating surface 20. In this specification, for the sake of simplicity, PBS
The light traveling straight through 14 is P-polarized light, and the light emitted by the light separation surface is S-polarized light. Two PD panels 15a and 15b of the present invention are attached to the PBS 14.

A transparent plate 16 is connected to the light exit side of the PD liquid crystal panel 15 via a transparent body 42b. A spacer (not shown) is provided around the periphery between the glass substrate 141 and the transparent plate 41, and the transparent body 4 is provided by the spacer.
2b is regulated. A black paint 32 is applied to the side surface of the transparent plate 41, and an antireflection film is applied to an effective area of an emission surface of the transparent plate 41. The refractive indexes of the transparent plate 41 and the glass substrate 141 are both 1.52. The transparent body 42 is a transparent silicone resin KE manufactured by Shin-Etsu Chemical Co., Ltd.
1051, the thickness is 2 mm, and the refractive index is 1.40. This is supplied as two kinds of liquids, and when the two liquids are mixed and left or heated at room temperature, they are cured into a gel by an addition polymerization reaction.

As the transparent plate 41, a transparent resin such as an acrylic resin may be used. The transparent body 41 only needs to be transparent, and a liquid such as ethylene glycol, an epoxy-based transparent adhesive, a transparent silicone resin which cures in a gel state by ultraviolet irradiation, or the like can be used. In any case, if there is an air layer between the glass substrate 141 and the transparent plate 41, image quality abnormality occurs there, so it is necessary to exclude the air layer. Similarly, the PBS 14 and the transparent binder 4
Optically coupled by 2a.

The thickness t of the transparent plate 41 is such that the maximum diameter of the effective display area of the liquid crystal layer 121 for forming an optical image as a change in the light scattering state is d, and the refractive index of the transparent substrate 41 is n.
The following equation should be satisfied.

[0125]

(Equation 2)

It is sufficient for practical use if the condition of (Equation 2) is satisfied.

[0127]

(Equation 3)

Is satisfied. Hereinafter, the transparent plate 41
The effect of will be described. The explanatory diagram is shown in FIG. First, FIG. 4A shows a case where a liquid crystal layer 121 is sandwiched between glass substrates 141 and 142 of about 1 mm like a conventional TN liquid crystal panel. The incident light A is applied to the liquid crystal layer 14.
Scatter at 2. This scattering is called primary scattering. Part of the scattered light is reflected at the interface 31 with the air. If the angle exceeds the critical angle in Snell's law, total reflection occurs. The reflected light a returns to the liquid crystal layer 121 and is scattered again. This scattering is called secondary scattering. Therefore, light due to primary scattering and secondary scattering is emitted forward.

As shown in FIG. 41B, the opposite substrate 14
When the thickness t of 1 is increased, the light is primarily scattered, and the light reflected at the interface 31 with the air is incident on an invalid area (specifically, a side surface) of the display panel as indicated by a ′. If a black paint is applied to the side surface and the light a ′ is absorbed, no secondary scattering occurs.

As described above, as the thickness t increases, 2
When the secondary scattering decreases and the condition of (Equation 2) is satisfied, almost no secondary scattering occurs. If the secondary scattering is eliminated, the display contrast becomes good.

Normally, the thickness of the counter substrate 141 is about 1 mm, and when the thickness is too large, handling becomes difficult in manufacturing a PD liquid crystal panel. Therefore, as shown in FIG. 4D, the transparent plate 41 is attached to the counter substrate 141 via the transparent coupling body. As shown in FIG. 4C, if the shape of the transparent plate 41 or the counter substrate 141 is concave, the angle of light reflected at the interface 31 with the air becomes large as shown by the light beam b. Even if the substrate thickness (center thickness) is thin,
The effect of preventing secondary scattering increases.

The above items are described in more detail in Japanese Patent Application Laid-Open No. 4-145277, so please refer to them. In this specification, the technical ideas and the contents described in the above publications are applied as they are or as appropriate. For example, in FIG. 6, the configuration using the concave lens 43 as shown in FIG. 6B, as well as the configuration shown in FIG. 6A, and the concave lens as shown in FIG. 43 positive lens 6
1 is also included. The configuration, effects and the like of these concave lenses and the like are described in detail in the above-mentioned publication, so please refer to them. In FIG. 6, one of the two liquid crystal panels is not shown.

Also, as shown in FIG.
The light absorbing film 171 is formed in an invalid area on the surface of the prism. The light absorbing film 171 is exemplified by a black paint applied to the top of the lens.
Material may be used.

In addition, a prism 1
81, a light absorbing film 171 formed in an ineffective area;
A configuration in which a plate or a film that absorbs light is attached to the ineffective area of the prism 181 and a configuration in which the ineffective area of the prism 181 is polished to a scattering state are exemplified.

The invalid area mainly indicates an area other than the PD liquid crystal panel 15 and the light input / output surface 172. The light absorbing film 171 has a function of absorbing light scattered by the PD liquid crystal panel 15.

Next, the effect of attaching the PD liquid crystal panel 15 to the PBS 14 will be described with reference to FIG.

The S-polarized light enters the liquid crystal panel 15a.
The S-polarized light is scattered by the liquid crystal layer 121. Scattering produces a P-polarized component. The scattered and reflected light (S-polarized light, P-polarized light) again enters the opposite substrate 141 and is
Come back to 4. Of the returned light, the S-polarized light is reflected again by the light separating surface 20 and returns to the direction a. That is, it returns to the light source side. The P-polarized light passes through the light separating surface 20, and b
Emit in the direction. This is because the transparent plate 41 is provided on the counter substrate 141 side.
Can be obtained. If the PBS 14 and the opposing substrate 141 are not optically coupled, the scattered light is reflected at the interface between the opposing substrate 141 and air, and returns to the liquid crystal layer 121 again to cause secondary scattering. Because the PBS 14 can be regarded as a thick transparent plate, the reflected light
Since no secondary scattering occurs, the display contrast is improved.
Of course, the light scattered by the PD liquid crystal panel 15 and incident on the invalid area of the PBS is absorbed by the light absorbing film 171.

In the case of (FIG. 1), the polarizing plate 17 is attached to the exit surface of the transparent plate 41. The polarization axis of the polarizing plate 17 allows light to pass when the liquid crystal layer 121 is in a transparent state (ON state). The liquid crystal layer 121 is in a scattering state (OFF
State), the polarization state is broken (a part of the P-polarized light is converted to an S-polarized light, and a part of the S-polarized light is converted to a P-polarized light). Since the polarized light is absorbed by the polarizing plate 17, the contrast between the transmission state and the scattering state is improved, and a favorable image display can be performed.

Light transmitted through the two liquid crystal panels 15a and 15b is enlarged and projected at substantially the same position by the projection lens 18 to display an image. Note that, as shown in FIG. 3, even without the polarizing plate 17, the contrast is reduced, but it goes without saying that an image can be displayed. In this case, since there is no polarizing plate 17, there is no light absorption by the polarizing plate, and the displayed image becomes bright.

As shown in FIG. 2, PBSs 14a and 1
If 4b is used, an image can be enlarged and projected by one projection lens 18. The optical path length that passes through the two liquid crystal panels 15 from the lamp 11b and reaches the projection lens can be the same. In addition, since the PBS 14b plays the role of the polarizing plate 17, the display contrast is higher than that of the configuration shown in FIG. Further, since the PBS does not absorb light like a polarizing plate, the displayed image is brighter than the configuration shown in FIG. Note that the PD liquid crystal panel 15 may be attached to the PBS 14b. In this case, the transparent substrate 41 and the like are arranged on the light incident surface to the panel.

As described above, in the projection type display device of this embodiment, the light emitted from the light source is separated into the P-polarized light and the S-polarized light by the PBS 14, and the PD liquid crystal panel 15 is arranged in each of the optical paths. Things. That is, two PD liquid crystal panels are used. In addition, a projection lens is provided, and the projection lens enlarges and projects the light modulated by the liquid crystal panel on a screen. The images on the two liquid crystal panels 15 are superimposed and projected. However, it is preferable that the images are superimposed with a shift of one pixel row or more or one image column or more.

Each liquid crystal panel has color filters of three primary colors of R, G and B, and by shifting one pixel,
This is because the two colors are additively mixed on the screen, and the definition is improved.

Preferably, additive color mixing is performed.
The polarities of the video signals applied to the two pixels are opposite to each other. The above matters will be described in more detail below with reference to FIG.

The light modulated by each of the liquid crystal panels 15a and 15b is combined by the PBS 14b, enters the projection lens 18, and is enlarged and projected on a screen. 13a, 13
b and 13c are mirrors.

The liquid crystal panels 15a and 15b are projected on a screen (not shown) in an overlapping manner, and the overlapping is performed as shown in FIG. (FIG. 8A) shows a projection image 81.
This is a case where a and 81b are overlapped by being shifted by one pixel column. Assuming that the arrangement of the color filters of the projected images 81a and 81b is as shown in FIG. 9, the pixel A is a color in which the R color and the G color overlap, and the pixel B is a color in which the G color and the B color overlap. But,
The pixel C displays a color in which the B color and the R color overlap. As a matter of course, in the liquid crystal panels 15a and 15b, the sampling of the video signal also needs to be performed by shifting one pixel column.
When the projection is performed as described above, the resolution of the projection image is higher and the screen brightness is improved as compared with the projection image of the projection type display device using one conventional liquid crystal panel. Further, even if one of the two liquid crystal panels has a pixel defect, the pixel defect is not easily recognized. For example, even if the pixel A of the projection image 81b is a point defect, it is extremely rare that the pixel of the liquid crystal panel superimposed on the pixel A of the projection image 81a is also a defect. Therefore, if the pixel of one of the liquid crystal panels is normal, the image is normally displayed, so that it is not regarded as a defect. However, the pixel defect must be a black defect (a pixel defect of black display constantly). For this purpose, process control must be performed so that a white defect (a pixel defect that constantly causes white display) does not easily occur in a TFT forming process. Further, defect correction may be performed using a laser beam or the like so that white defects become black defects.

As a matter of course, as shown in FIG. 8 (b), there is also a method of projecting the projected images 81a and 81b by shifting one pixel and overlapping each other. If the color filters of the pixels are arranged as shown in FIG. 9, the R and G colors are at the position of the pixel D, the G and B colors are at the position of E, and the B and B colors are at the position of F.
The display is such that the color and the R color overlap. The effects and the like are the same as those described above, and will not be described.

In the above-described embodiment, the projected images are shifted by one pixel row or one pixel column to overlap each other. However, the present invention is not limited to this. For example, the projected images may be shifted by two pixels to overlap each other. It should be noted that a projection image in an area that is not overlapped may be shielded from light by using a mask or the like so as not to be displayed.

There is also a method of shifting by half a pixel instead of by one pixel. If the pixels are shifted by half a pixel, an image of the pixel of the liquid crystal panel 15b is projected between the pixels of the liquid crystal panel 15a. The black matrix is not displayed on the projection image, and an effect of obtaining a smooth projection image is obtained.

Further, the case where the same color filter is attached to the two liquid crystal panels 15a and 15b has been described above. However, if measures are taken for the color filters, the images may be superimposed without performing the pixel shift.
That is, the projection images of the liquid crystal panels 15a and 15b may be made to coincide with each other and projected. For example, when the upper left pixel of the color filter of the liquid crystal panel 15b is an R color filter, the upper left pixel of the color filter of the liquid crystal panel 15a is a G color. That is, the color filters are formed in different color arrangements in the liquid crystal panels 15a and 15b. In this case, the two projection images are completely matched.
Of course, the color filters must be formed so that two different colors are additively mixed, such as the R color of the liquid crystal panel 15a being the G color of the liquid crystal panel when they are matched. The sampling of the video signal may be performed at the same timing for the two liquid crystal panels. Therefore, the projection of the present invention with the pixels shifted is defined as the RG of the color filter described above.
Consideration should be given to the case where the color B is shifted.

In the projection display apparatus of the present invention, one line (H inversion drive) is provided on the liquid crystal panel in order to prevent the occurrence of flicker.
Alternatively, signals having different polarities are applied to each column (column inversion drive). Of course, as shown in FIG. 39, the polarity may be changed every two columns or every two rows. The explanation is shown in (FIG. 10) and (FIG. 11).

FIG. 10 shows a driving method called column inversion driving. In the figure, a pixel to which a signal of positive polarity is written is indicated by "+", and a pixel to which a signal of negative polarity is written is indicated by "-". FIG. 10A shows the polarity of a signal written to a pixel in a field at a certain time. Signals of opposite polarities are written in adjacent pixel columns. In the next field, the polarity is as shown in FIG.
That is, a pixel to which a signal of positive polarity is written is written with a signal of negative polarity in the next field, and a pixel to which a signal of negative polarity is written is written with a signal of positive polarity in the next field.

FIG. 11 shows a driving method called H inversion driving. FIG. 11A shows a state of a signal written to a field pixel at a certain time, and a positive polarity signal and a negative polarity signal are written for each row. The next field is as shown in FIG. 11 (b). That is, the polarity of the signal is inverted as in the above-described driving method.

In the projection type display device of the present invention, in the overlapped pixels, the positive polarity and the negative polarity are overlapped. In FIG. 8, if the pixel A of the projection image 81b is optically modulated by the signal of the positive polarity, the pixel of the projection image 81a overlapping the pixel A is optically modulated by the signal of the negative polarity. Driving as described above can greatly reduce flicker.

As is clear from the above, (FIG. 8
When the projected images are overlapped as in (a)), the column inversion drive is performed. When the projected images are overlapped as shown in FIG. 8B, H inversion driving is performed.

In addition to the driving methods shown in FIGS. 10 and 11, there is a method called a pseudo-interlace driving method. The above-mentioned method is a method of writing signals of the same polarity every two pixel rows as shown in FIG. More precisely, the same image is displayed on two pixel rows. To reduce flicker, pixel rows are shifted as shown in FIG. 8B.
However, the pixels are overlapped by being shifted by two pixel rows.

As previously described with reference to FIG. 39,
In the case of H inversion driving, a horizontal electric field is easily generated in the bb 'direction. Therefore, light of polarized light in the aa ′ direction is easily transmitted. Therefore, light should be incident on the PD liquid crystal panel 15 so that the polarization direction is bb '. If it is assumed that an image is displayed on the PD liquid crystal panel 15 by H inversion driving and that P-polarized light is incident on the panel,
The polarization direction of the P-polarized light should be the bb 'direction. In the case of the column inversion driving, a horizontal electric field is likely to be generated in the aa 'direction. Therefore, the polarization direction of P-polarized light is a
It should be in the a 'direction.

As described above, in consideration of the driving method of the PD liquid crystal panel and the polarization direction (polarization axis) of the polarized light emitted from the PBS 14, the projection type display device shown in FIGS.

(FIG. 2) shows liquid crystal panels 15a and 15a.
The light modulated by b is combined by the PBS 14a and projected by one projection lens 15 on a screen.
However, the above-described technical idea of overlapping pixels is not limited to this. For example, as shown in FIG. 3, a configuration in which projection is performed on a screen using two projection lenses 18a and 18b may be employed. With the configuration of (FIG. 3), (FIG. 2)
No PBS 14a is required.

The projection display device described above uses the PBS 14 as the light separating means. A projection display apparatus according to a second aspect of the present invention uses a dichroic prism 181 as light separating means. That is, the PD liquid crystal panel 15 is connected to the prism 181 via the optical coupling layer 42.
This is because the technical idea of the present invention of attaching the light absorbing means 171 in the ineffective area of the prism 181 is common to the previous embodiment.

FIG. 28 is a configuration diagram of an embodiment of a projection display device using the reflective PD liquid crystal panel 15 of the present invention shown in FIG. 26 and the like as a light valve.

The projection lens 181 has a first lens group 181b on the display panel side and a second lens group 181a on the screen side.
And the first lens group 181a and the second lens group 1
The flat mirror 13 is arranged between the flat mirror 81b and the flat mirror 81b. P
After passing through the first lens group 181b, about half of the scattered light emitted from the pixel at the center of the screen of the D liquid crystal panel 15 is incident on the plane mirror 13 and the rest is not incident on the plane mirror 13 but the second lens The light enters the group 181a. Flat mirror 1
The normal of the reflecting surface of No. 3 is inclined by 45 ° with respect to the optical axis 281 of the projection lens 181. Light from the light source 11 is reflected by the plane mirror 13 and passes through the first lens group 181b,
The light enters the liquid crystal panel 15. The reflected light from the PD liquid crystal panel 15 is transmitted to the first lens group 181b and the second lens group 181.
The light passes through in the order of a and reaches the screen 284. Light rays that exit the center of the stop of the projection lens 181 and travel toward the PD liquid crystal panel 15 are made to enter the liquid crystal layer 121 almost perpendicularly, that is, telecentric.

Here, for ease of explanation, 15a
Is described as a PD liquid crystal panel that modulates R light, 15c is a PD liquid crystal panel that modulates B light, and 15b is a PD liquid crystal panel that modulates G light.

In FIG. 28, reference numeral 181 denotes a dichroic prism, which serves both as a color synthesizing system and a color separating system. The white light emitted from the light source is a flat mirror 1
3 and the first group 18 of the projection lens 181
1b. At this time, unnecessary B light and R light are cut by the filter 12. The band of the filter 12 has a half value of 430 nm to 690 nm. Hereinafter, when describing the band of light, it is expressed by a half value. The light separating surface 20 of the dichroic prism 181 reflects R light and transmits G light. The R light is reflected by the light separation surface 20a of the dichroic prism 181 and enters the PD liquid crystal panel 15c. G
The light band is 510 to 570 nm. The G light enters the PD liquid crystal panel 15b, and the R light enters the PD liquid crystal panel 15a. The band of incident B light is 430 nm to 490 nm,
The light band is from 600 nm to 690 nm. Each PD liquid crystal panel forms an optical image as a change in the scattering state according to each video signal. The optical image formed by each PD liquid crystal panel is recombined by the dichroic prism 181, enters the projection lens 181, and is enlarged and projected on the screen 284.

By using a reflective structure for the PD liquid crystal panel, a heat radiating plate or the like can be directly disposed on the array substrate 161. The heat sink is a panel 15 made of silicone adhesive.
Attach. With this configuration, the PD liquid crystal panel can be easily cooled.

Light incident on the display panel passes through the liquid crystal layer 121 twice, from the counter electrode 261b to the reflective electrode 262 (incident path) and from the reflective electrode 262 to the counter electrode 261b (output path). Become. Therefore, the thickness of the liquid crystal 121 is apparently the same as that of the liquid crystal 121 formed twice as thick as the transmissive PD liquid crystal panel. Therefore, the scattering performance is improved as compared with the transmission type PD liquid crystal panel, and a high contrast display can be realized.

Further, by using the dichroic prism 181 for both the color separating function and the color synthesizing function, the system size of the projection display device can be reduced.
Each PD liquid crystal panel 15 is optically coupled by an optical coupling layer 42 and is attached.

As shown in FIG. 18, a light absorbing film 171 is applied to the invalid area of the dichroic prism 181.

The PD liquid crystal panel 15 is attached to a dichroic prism 181, and a light absorbing film 171 is applied to an invalid area of the dichroic prism 181. This configuration is the same as that described in FIG.
That is, the PBS 14 may be replaced with the dichroic prism 181.

For example, if the PD liquid crystal panel 15a is considered as the center and the PD liquid crystal panel 15a modulates the R light, the incident light 283a is reflected by the dichroic prism 1a.
The R light enters from the light entrance / exit surface 172 of the light 81 and is reflected by the light separating surface 20b. The PD liquid crystal panel 15a has a reflective electrode 2
Light modulation layer 121 according to the magnitude of the voltage applied to
Is changed. Among these, the component of the transmitted light is reflected again by the light separating surface 20b, and is emitted from the light input / output surface 172. Most of the scattered light enters the light absorption film 171 and is absorbed, and returns to the light modulation layer 121 again, without causing secondary scattering. Therefore, the display contrast is improved.

Although FIG. 28 is shown in a two-dimensional diagram for easy understanding, this configuration has a problem. This is because there is an angle difference between the light entering and exiting the light separation surface 20 of the prism 181 and a difference in the spectral reflectance between the P-polarized light and the S-polarized light, thereby lowering the color purity of the projected image. Therefore, in reality, it should be configured as shown in FIG. This is the same in (FIG. 19).

The configuration shown in FIG. 29 will be described below. In the configuration shown in FIG. 29, the plane including the optical axis 283b of the illumination light emitted from the light source 11 and the optical axis 283a of the projection light reflected by the PD liquid crystal panel 15 is P
It is arranged perpendicular to a plane including the center normal of the D liquid crystal panel 15 and the center normal of the light separation surface 20 of the dichroic prism 181. Therefore, the surface including the optical axis 283b and the optical axis 283a forms an angle of 45 ° with the color separation / combination surface 20 of the dichroic prism 181. Therefore,
Both the illumination light and the projection light can be incident on the light separation surface of the dichroic prism 181 at the same incident angle of 45 °.

The spectral transmittance of the dichroic prism 181 is shown in FIGS. 34 (a) and (b). (FIG. 34 (a))
Shows the spectral transmittance when the light incident angle on the light separating surface 20 of the dichroic prism is 45 °. The light separating surface 20 is of a type that reflects R light and transmits G light and B light. FIG. 34B shows the spectral transmittance when the light incident angle on the light separation surface 20 of the dichroic prism 181 is 45 °. The light separation surface 20 reflects B light and G light. Is a type that transmits light.

According to the structure of this embodiment, the spectral performance in the case of color separation and the spectral performance in the case of color synthesis match, so that the spectral performance shown in FIGS. It can be reflected on the projected image.

For comparison, the case of FIG. 28 will be described below. If the optical axis 283a of the illumination light is assumed to be incident on the PD liquid crystal panel 15 at 5 °, the optical axis 283a of the illumination light and the optical axis 283b of the projection light form an angle of 10 °, and the dichroic prism of the illumination light. The angle of incidence on the separation surface is 40 °, and the angle of incidence of the projection light on the light separation surface of the dichroic prism is 50 °. The spectral transmittances when the incident angle is 40 ° and when the incident angle is 50 ° are shown in FIG.
(B)). (FIG. 35 (a)) shows the light separating surface 20b,
(FIG. 35 (b)) shows the spectral transmittance of the light separating surface 20a, and the solid line in the figure shows the case where the incident angle of the light beam is 40 °.
The dotted line shows the case where the incident angle of the light beam is 50 °. From FIGS. 35A and 35B, the spectral performance of the illumination light and the spectral performance of the projection light are significantly different due to the wavelength shift depending on the incident angle, and the desired color purity can be obtained without lowering the light use efficiency. It turns out that it is difficult to obtain.

The dichroic prism 181 (see FIG. 1)
The configuration of 9) may be considered. Cube shaped container 19
1, a dichroic mirror (a half mirror in which a dielectric multilayer film is formed on a glass plate or the like and which reflects light by selecting a wavelength of light by an optical interference phenomenon) 193 and a PD display panel 15 are arranged. A light absorbing film 17a as light absorbing means is formed on the inner surface or outer surface of the container 191. The space of the container 191 is filled with a liquid such as ethylene glycol or a gel 192.

With the above configuration, the PD liquid crystal panel 1
5 eliminates the need for optical coupling.
The light absorbing film 171a shown in FIG. 19 functions as the light absorbing film 171 shown in FIG. In addition, since the liquid or gel 192 has a function of liquid cooling the PD liquid crystal panel 15, the cooling of the PD liquid crystal panel 15 is easy.

The configuration shown in FIG. 29 is a reflection type projection display device. However, the technical idea of the present invention can be applied not only to the reflection type but also to the transmission type projection display device.

(FIG. 30) is a configuration diagram of a transmission type projection display apparatus of the present invention. Dichroic prism 181b
, Three PD liquid crystal panels 15 are optically connected by an optical coupling layer 42. It is preferable that the optical coupling layer 42 has a gel shape. This is because it is necessary to perform alignment so that the three PD liquid crystal panels 15 just overlap on the screen. If the position of the PD liquid crystal panel 15 is completely fixed, alignment is impossible. If it is a gel, the position can be slightly changed. In the projection display device of the present invention, when a configuration in which the display panel is attached to the prism is adopted, a mechanism for changing the position of the display panel is added. It goes without saying that the PD liquid crystal panel 15 may be attached to the dichroic prism 181a.

The white light emitted from the metal halide lamp 11b is separated by the light separation surfaces 20c and 20d of the dichroic prism 181a into light paths of three primary colors of R, G and B. The R light is reflected by the mirrors 13c and 13d and enters the PD liquid crystal panel 15c. The G light goes straight and enters the PD liquid crystal panel 15b. On the other hand, the B light is reflected by the mirrors 13a and 13b, and the PD liquid crystal panel 1
5a. Since the optical path lengths of the R and B lights are longer than the optical path length of the G light, it is preferable to arrange a relay lens in the optical paths of the R and B lights. The light separating surface 20d of the prism 181a reflects the R light, and the light separating surface 20c reflects the B light. However, the present invention is not limited to this. The light separating surface 20d reflects the B light and performs the light separation. The surface 20c may reflect the G light.

Each PD liquid crystal panel 15 modulates each incident light. The prism 181b combines the modulated light into one optical path, and the combined light enters the projection lens 181 and is projected on a screen.

The light absorbing film 1 is provided on the inactive surface of the prism 181b.
Since the light 71 is applied and the light scattered by the PD liquid crystal panel 15 is absorbed by the light absorbing film 171, the generation of secondary scattered light is suppressed and the display contrast is improved. Also, the window contrast is very good. Also,
In order to prevent the secondary scattering due to the back scattering generated in the PD liquid crystal panel 15, the transparent substrate 41 or the concave lens may be bonded to the PD liquid crystal panel 15 with the optical coupling layer 42a as shown by the dotted line in FIG. Of course, it is preferable to form the light absorbing film 32 in the invalid area of the transparent substrate 41 as shown in FIG.

A driving circuit and a driving method of a projection display device when three light valves for modulating red, green and blue light are used will be described. FIG. 32 is an explanatory diagram of a drive circuit in one embodiment of the projection display apparatus of the present invention. In FIG. 32, reference numeral 15a denotes a PD for modulating the R light.
A liquid crystal panel, 15b is a PD liquid crystal panel for modulating G light,
Reference numeral 15c denotes a PD liquid crystal panel that modulates B light, and R ₁ and R ₂ and a transistor Q constitute a phase division circuit that creates a positive and negative video signal of a video signal input to a base. This corresponds to 312 in (FIG. 31). Reference numeral 313 denotes an output switching circuit that outputs an AC video signal whose polarity is inverted every one horizontal scanning period (1H) or one vertical scanning period (1V) to the PD liquid crystal panel.

After the gain of the video signal is adjusted to a predetermined value,
The light is divided into signals corresponding to the R, G, and B lights. The divided video signals are referred to as a video signal (R), a video signal (G), and a video signal (B), respectively. Video signal (R)
(G) and (B) are respectively input to the phase division circuit, and two positive and negative video signals are generated by this circuit. Next, the two video signals are input to respective output switching circuits 313, and the output switching circuits
The polarity of the output signal is changed every H or 1V. Next, the video signal from each output switching circuit 313 is input to the source drive circuit 314 shown in FIG. The drive control circuit 315 synchronizes the source drive circuit 314 with the gate drive circuit 316,
An image is displayed on the D liquid crystal panel 15.

Next, the visibility of the human eye will be described.
The human eye has the highest sensitivity near the wavelength of 550 nm. Of the three primary colors of light, green is the highest, red is the next, and blue is the least sensitive. In order to obtain a luminance signal proportional to this sensitivity, it is sufficient to add 30% of red, 60% of green and 10% of blue. Therefore, in order to obtain white color in a television image, it is only necessary to add R: B: G = 3: 6: 1. Further, as described above, the liquid crystal needs to be driven by an alternating current. This AC driving is performed by alternately applying a positive polarity signal and a negative polarity signal to a voltage (hereinafter, referred to as a common voltage) applied to a counter electrode of the PD liquid crystal panel. In this embodiment, + n indicates a state in which a positive signal is applied to the PD liquid crystal panel to modulate light having a luminosity n, and a negative signal is applied to modulate light having a luminosity n. Is represented by -n.

For example, light of R: G: B = 3: 6: 1 is PD
When the liquid crystal panel is irradiated, a positive signal is applied to the R and B PD liquid crystal panels (15a, 15c), and a negative signal is applied to the G PD liquid crystal panel 15b. -6 · + 1. In addition,
R: G: B = 3: 6: 1 is the case of NTSC television video, and in a projection display device, the above ratio varies depending on the lamp of the light source, the spectral characteristics of the dichroic mirror, and the like. In FIG. 32, + 3−−6 · + 1 is indicated. This is because when attention is paid to an arbitrary image of each PD liquid crystal panel superimposed on the same position on the screen, light of R: G: B = 3: 6: 1 is applied to each pixel, and R and B are illuminated.
The positive signal is applied to the pixels of the PD liquid crystal panel for G
This shows that a negative signal is applied to the pixels of the D liquid crystal panel. Each of the pixels is-
A signal application state expressed as 3 · + 6 · −1 is obtained.

However, in the projection display apparatus of the present invention, in addition to the driving method shown in FIG. 10 (FIG. 11) or (FIG. 39), the signal for G light modulation is converted to R.R. B
By setting the polarity opposite to that of the light modulation signal, flicker can be prevented from being visually observed. The reason why the G light modulation signal has the opposite polarity to the other light is that the light intensity is R: G: B =
3: 6: 1, taking into account the polarity of the signal and human vision, (R + B): G = (3 + 1): 6 = 4: 6, and almost 4: 6 (ideally 1: 1 is better. ).

For the above reasons, the projection type display apparatus according to the present invention can display good images without flicker being visually recognized.

The projection type display device is a transmission type screen 284.
And a projection device 332 in one cabinet 331 (see FIG. 33), and a front projection display device in which the reflection screen and the projection device are separated. The projection display device of the present invention can be applied to both a rear type and a front type. For example,
The projection type display device shown in FIG. 1 (FIG. 1), FIG. 29 (FIG. 30) and the optical system block 3 in the cabinet 331 (FIG. 33).
32, and is configured to be reflected by the mirrors 13a and 13b and projected on a transmission type screen 284, a rear projection display device can be configured. (FIG. 37) (FIG. 38) and (FIG. 39) have been described assuming that the liquid crystal molecules have a positive dielectric constant. Therefore, the horizontal electric field is a
When it occurs in the direction of a ', the liquid crystal molecules are oriented in the direction of aa'. Therefore, polarized light in the bb 'direction is easily transmitted.

However, when the liquid crystal molecules have a negative dielectric constant, the above relationship is reversed. In the case of having a negative dielectric constant, when a transverse electric field is generated in the aa 'direction, it can be regarded as equivalent to the orientation by the method of bb'. Therefore, polarized light in the aa ′ direction is easily transmitted.

When the liquid crystal molecules have a positive dielectric constant, the driving method shown in FIG. 39 facilitates transmission of polarized light in the aa 'direction. Therefore, the polarization axis of the polarizing plate is made substantially coincident with the pixel column direction (bb 'direction). Also,
In the case of column inversion driving, the polarization axis of the polarizing plate is made to coincide with the pixel row direction (aa ′ direction).

The description in the present specification and claims is based on the assumption that liquid crystal molecules have a positive dielectric constant. In practice, most practical liquid crystals have a positive dielectric constant. However, a liquid crystal having a negative dielectric constant may be used. Therefore, when a liquid crystal having a negative dielectric constant is used, the description of the specification and claims of the present invention must be read. More specifically, when the liquid crystal has a negative dielectric constant, when the H inversion drive is performed, the polarization axis of the polarization unit is set to the pixel row method (the direction in which the gate signal line is formed).
When the column inversion drive is performed, the polarization axis of the polarization unit is set to the pixel column method (the direction in which the source signal line is formed).

As described above, the present specification and claims must be read so as to be suitable for the case of a negative dielectric constant. This is because there is no change in the technical idea intended by the present invention.

[0193]

The liquid crystal panel of the present invention can shield the electric field generated from the signal line 144 and the like by covering the signal line 144 and the like with the light shielding film 73 as shown in FIG. , A horizontal electric field can be prevented, and the pixel electrode 143 can be prevented.
Light leakage in the peripheral part can be prevented. Therefore, display contrast can be improved.

Also, as shown in FIG.
By forming 1, the electric field from the signal line is almost completely shielded, and no light leakage occurs. The low light-shielding columns 211 also have a function of defining the thickness of the liquid crystal layer 121. That is, it serves as a bead for defining the liquid crystal film thickness. Therefore, there is no need to spray beads. Therefore, there is no light leakage around the beads and the display contrast is good.

As shown in FIG. 22 and the like, by setting the optimum average particle size for the color of the color filter, a good display contrast can be obtained. Also, as shown in FIG. 23, if the source signal lines 144 and the like are covered with the color filters 72 and electromagnetically shielded, only the source signal lines 144 and the like are simultaneously covered when the color filters 72 are formed. It is easy to manufacture. The color filter is a resin material and has a relatively low relative dielectric constant, and can have the same effect as the light shielding film 73.

As shown in FIG. 25, if the average particle diameter of the water-drop liquid crystal on the source signal line 144 or the like is made very small, the liquid crystal will not respond to the voltage application. The same effect as when the light-shielding pillar 211 is formed on the source signal line 144 or the like can be obtained. In other words, if the average particle size is very small, no response is made to the lateral electric field. Therefore, light leakage from the periphery of the pixel or the like is eliminated. In addition, since it is always in a scattering state, B
The same effect as when M is formed can be obtained.

When a polarizing means such as a PBS is used, the polarization axis of the polarizing means is made to coincide with the direction in which the horizontal electric field is generated. Further, the generation direction of the lateral electric field is controlled in consideration of the driving method. By making the polarization axis of the polarization means coincide with the direction of generation of the transverse electric field, light leakage from the peripheral portion of the pixel electrode 143 can be completely prevented,
High contrast display can be performed.

Further, in the display panel of the present invention, by employing the H inversion drive and the column inversion drive as shown in FIGS. 10 and 11, it is possible to define the direction in which the horizontal electric field is generated and to reduce the occurrence of flicker. Can be prevented. Further, in the projection display apparatus of the present invention, by employing the driving method described with reference to FIG. 32, flicker can be further sufficiently prevented, and excellent image display can be realized.

In the projection display apparatus of the present invention, the PBS
Further, the PD liquid crystal panel 15 is attached to the dichroic prism 181, and a light absorbing film 171 is applied to an invalid area such as the PBS 14. Therefore, most of the light scattered by the PD liquid crystal panel 15 is incident on the light absorbing film 171 and is absorbed, so that the light returns to the light modulation layer 121 again and does not cause secondary scattering. Therefore, the display contrast is improved.

Further, as shown in FIG. 8, if the projected images of the two PD liquid crystal panels 15 are shifted by one pixel and projected one upon another, additive color mixing can be performed, and two PD liquid crystal panels 15 can be formed.
The resolution can be improved by sampling the video signal on the liquid crystal panel so as to be suitable for performing the additive color mixture. In addition, if the polarities of the pixels at the superimposed positions are set to opposite polarities, flicker can be prevented. Further, the light scattered by the liquid crystal layer 121 is not returned to the liquid crystal layer 121 again by the transparent substrate 41 and the PBS 14, so that the display contrast can be improved.

Further, by setting the polarities applied to the pixels at the superimposed positions to be opposite to each other, the occurrence of flicker can be greatly reduced, and the image quality can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a projection display device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a projection display device according to another embodiment of the present invention.

FIG. 3 is a configuration diagram of a projection display apparatus according to another embodiment of the present invention.

FIG. 4 is an explanatory view of a PD liquid crystal panel of the present invention.

FIG. 5 is a partial configuration diagram of a projection display device of the present invention.

FIG. 6 is a partial configuration diagram of a projection display device of the present invention.

FIG. 7 is a partial sectional view of a PD liquid crystal panel of the present invention.

FIG. 8 is an explanatory diagram of a projection image of the liquid crystal projection type television of the present invention.

FIG. 9 is an explanatory diagram of a color filter.

FIG. 10 is an explanatory diagram of a driving method of a liquid crystal panel.

FIG. 11 is an explanatory diagram of a driving method of a liquid crystal panel.

FIG. 12 is an explanatory diagram of a polymer dispersed liquid crystal.

FIG. 13 is a configuration diagram of a conventional projection display device.

FIG. 14 is a sectional view of a liquid crystal panel.

FIG. 15 is an explanatory diagram of a color filter.

FIG. 16 is an explanatory diagram of a driving circuit of a liquid crystal panel.

FIG. 17 is a perspective view of an optical component of the projection display device of the present invention.

FIG. 18 is a perspective view of an optical component of the projection display device of the present invention.

FIG. 19 is a sectional view of a PD liquid crystal panel of the present invention.

FIG. 20 is a sectional view of a PD liquid crystal panel of the present invention.

FIG. 21 is a sectional view of a PD liquid crystal panel of the present invention.

FIG. 22 is a sectional view of a PD liquid crystal panel of the present invention.

FIG. 23 is a sectional view of a PD liquid crystal panel of the present invention.

FIG. 24 is a sectional view of a PD liquid crystal panel of the present invention.

FIG. 25 is a sectional view of a PD liquid crystal panel of the present invention.

FIG. 26 is a sectional view of a PD liquid crystal panel of the present invention.

FIG. 27 is a sectional view of a PD liquid crystal panel of the present invention.

FIG. 28 is a configuration diagram of a projection display device of the present invention.

FIG. 29 is a configuration diagram of a projection display device of the present invention.

FIG. 30 is a configuration diagram of a projection display device of the present invention.

FIG. 31 is a block diagram of a driving circuit of a liquid crystal panel.

FIG. 32 is an explanatory diagram of a drive circuit of the projection display device of the present invention.

FIG. 33 is an explanatory diagram of a rear projection display device.

FIG. 34 is a characteristic diagram of optical components of the projection display device.

FIG. 35 is a characteristic diagram of optical components of the projection display device.

FIG. 36 is an explanatory diagram of P-polarized light and S-polarized light.

FIG. 37 is an explanatory diagram of polarization dependence.

FIG. 38 is an explanatory diagram of a method for driving a liquid crystal panel of the present invention.

FIG. 39 is an explanatory diagram of a method for driving a liquid crystal panel of the present invention.

[Explanation of symbols]

 11a Concave mirror 11b Lamp 12 UVIR cut filter 12a UVIR cut mirror 13a, 13b, 13c, 13d Mirror 14, 14a, 14b Polarizing beam splitter 15a, 15b, 132 Liquid crystal panel 17a, 17b Polarizing plate 18a, 18b, 133 Projection lens 19 Reference Signs List 20 light separating surface 31 interface with air 32 black paint 41 transparent plate 42 light coupling layer 61 positive lens 71 TFT 72, 151 color filter 73 light shielding film 81a, 81b projection screen 82 pixel 121, 147 liquid crystal layer 122 water droplet liquid crystal 123 polymer 131 Light source 134 Screen 141 Array substrate 142 Counter substrate 143 Pixel electrode 144 Source signal line 145 Counter electrode 146 Color filter 148a, 148b Alignment film 162a, 162b, 162c Output Switching circuit 171 Light absorbing film 172 Light input / output surface 181 Dichroic prism 191 Container 192 Ethylene glycol liquid 192 Dichroic mirror 201 Insulating film 202 Black bead 211 Light shielding film 213 Electric flux lines 221 Ultraviolet absorbing film 261a, 261b Dielectric thin film 261b Counter electrode 262 Reflecting electrode 263 Connection part 264 Insulating film 281 Optical axis 282 Auxiliary lens 283a Incident light 283b Outgoing light 284 Screen 331 Cabinet 332 Optical block 361 Incident light 362 Radiation 363 Vibration direction 364 Dichroic mirror 365 P Polarization axis 366 Light separation surface 367 P polarization P polarization plane 369 Polarization axis of polarizing plate 371 Liquid crystal molecule

Claims (10)

(57) [Claims] A first substrate on which pixels are arranged in a matrix, a second substrate disposed at a position facing the first substrate, a first substrate and a second substrate. A light modulating layer made of a resin and a liquid crystal sandwiched between two substrates; and a driving unit for driving the liquid crystal display panel, wherein the driving unit applies a voltage every predetermined number of pixel rows of the liquid crystal display panel. The first drive in which the polarity of the signal is different and the polarity of the signal applied to the pixel is different in a predetermined time period, or the polarity of the signal applied is different for each predetermined number of pixel columns of the liquid crystal display panel The second drive is performed such that the polarity of the signal applied to the pixel is different from each other and at a predetermined time period. In the first drive, the polarization axis of the polarization separation unit is aligned with the pixel column direction. Arranged so that the front In carrying out the second driving, the liquid crystal display panel in which the polarizing axes of the polarized light separating means, characterized in that it is arranged such that the pixel row direction. 2. A first substrate on which pixel electrodes are arranged in a matrix, a second substrate on which a counter electrode is formed, and a liquid crystal layer sandwiched between the first substrate and the second substrate. A color filter composed of three primary colors is formed on the first substrate side, and a color filter of at least two colors is formed between the adjacent pixel electrodes, and a relative dielectric constant of the color filter is provided. Is a liquid crystal display panel having a relative permittivity smaller than that of the liquid crystal layer. 3. A switching element is formed in each pixel,
The switching element is formed by a low temperature polysilicon technology.
3. The liquid according to claim 1 or 2, wherein
Crystal display panel. 4. A substrate or a plate made of resin.
3. The device according to claim 1, wherein
LCD panel. 5. The liquid crystal has a negative dielectric constant.
3. The liquid crystal display panel according to claim 1, wherein: 6. A switching element is formed in each pixel.
And a light-shielding film is formed on the switching element.
3. The liquid crystal display according to claim 1, wherein:
panel. 7. A mark for each predetermined number of pixel rows of a liquid crystal display panel.
Signals with different polarities and with a predetermined time period
The first is to make the polarity of the signal applied to the pixel different.
Driving or every predetermined number of pixel columns of the liquid crystal display panel
The polarity of the signal to be applied to the
The polarity of the signal applied to the pixel is different.
And a driving circuit for performing the driving of (2).
The liquid crystal display panel according to claim 2. 8. A light generating means having an arc discharge lamp, a polarization separating means for separating light emitted by the light generating means into a P-polarized light path and an S-polarized light path, and modulating light from the polarized light separating means. A liquid crystal display panel in which pixels to be arranged are arranged in a matrix; a driving unit for driving the liquid crystal display panel; and a projection unit for projecting light modulated by the liquid crystal display panel. A first drive in which the polarity of the signal applied to each of the predetermined number of pixel rows of the liquid crystal display panel is different and the polarity of the signal applied to the pixels is different in a predetermined time period, or a predetermined driving of the liquid crystal display panel The second drive is performed so that the polarity of the signal applied to each pixel number is different and the polarity of the signal applied to the pixel is different at a predetermined time period, and the first drive is performed. In the second driving, the polarization axis of the polarization separation unit is arranged in the pixel row direction, and the polarization axis of the polarization separation unit is arranged in the pixel row direction. A projection display device. 9. A light-emitting surface of a liquid crystal display panel having a transparent plate optically coupled , wherein the maximum diameter of a display area of the liquid crystal display panel is d, and the refractive index of the transparent plate is n. 9. The projection display device according to claim 8 , wherein the thickness t of the plate satisfies the following condition. 10. A liquid crystal panel wherein pixel electrodes are matrix
The first substrate and the counter electrode are formed in
A second substrate, and a gap between the first substrate and the second substrate.
Liquid crystal layer provided on the first substrate side from three primary colors.
Color filter is formed, and the adjacent pixel electrode
At least two color filters are formed in an overlapping manner
The relative permittivity of the color filter is
9. The projection type display device according to claim 8 , wherein the relative dielectric constant of the projection type display device is smaller than the relative permittivity .