JP2801433B2 - Light modulation element and color electronic device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical modulator capable of changing the wavelength of transmitted light or reflected light continuously or stepwise easily and at high speed by controlling a voltage. Photodetectors such as imaging devices, which are color electronic devices configured using, color copiers, printing and plate making devices,
The present invention relates to an image input / output device such as a facsimile communication device, an image calculation device, and a lighting device.

[0002]

2. Description of the Related Art Liquid crystal display devices are used in a wide variety of fields such as watches, calculators, computer terminals, word processors and television receivers. A typical display mode used in these applications is a so-called T-mode in which liquid crystal molecules in a liquid crystal cell are twisted by about 90 ° as initial alignment.
This is an N (Twisted Nematic) mode. TN mode is 1
A liquid crystal cell is disposed between a pair of polarizing plates, and monochrome display is performed by utilizing the optical properties of the cell, that is, the optical rotation characteristics when no display voltage is applied and the optical rotation cancellation characteristics when a voltage is applied.

As for colorization, for example, a micro color filter having minute dimensions of, for example, red, blue, and green is provided for each display pixel in a liquid crystal cell, and the above-described optical switching characteristics of the TN mode are used. Color display (predetermined multiple color display) or full color display (stepless color display) is performed. This principle is currently employed as a display device of a small liquid crystal television receiver to which active matrix driving or simple matrix driving is applied.

As a display method widely used as a display device for a word processor, there is an STN (Super Twisted Nematic) mode in which the twist angle of liquid crystal is set to 180 ° to 270 ° with a cell structure similar to the TN mode. . This mode is characterized by increasing the twist angle of the liquid crystal to 90 ° or more and optimizing the setting angle of the polarization direction of the polarizer, thereby causing the sudden molecular orientation deformation accompanying the increase of the applied voltage to change the birefringence of the liquid crystal. To realize an electro-optical characteristic having a sharp threshold value. Therefore, it is suitable for simple matrix driving.

On the other hand, a disadvantage of this mode is that the display color is yellow-green or dark blue due to the birefringence of the liquid crystal. As an improvement method, a display STN
There is a technology that performs color correction by superimposing an optical compensation panel or a retardation plate made of a polymer such as polycarbonate on a panel to enable monochrome display. Currently, a liquid crystal display (LCD) having such a structure is provided. ) Is commercially available as “Paper White LCD”. Also, in this colorization, multicolor / full-color display can be performed based on the same operation principle as in the above-described TN mode.

For applications requiring a wide viewing angle, a so-called GH (guest host) mode in which a dye (dichroic dye) having a different absorbance in the major axis direction and the minor axis direction of the molecule is added to the liquid crystal. Is done. This method can be classified into a Heilmeier type using a polarizing plate, a white / Taylor type (phase change type) without using a polarizing plate, a two-layer type, and the like. Is controlled through the orientation of liquid crystal molecules by voltage, and the absorbance difference in the direction of the dye molecules is used for display. For colorization, display can be performed by using a dye that absorbs a part of the wavelength of visible light as a dye, or by combining a GH cell using a black dye with a color filter.

As another color display method, there is a method in which an element capable of controlling the wavelength of transmitted light is installed on the front or back of a monochrome display device, and color display is performed by sequentially switching the wavelength of the transmitted light. . As an example of applying this method to a projection display device, a polymer-dispersed liquid crystal is used as a CdSe-TFT panel (TFT = thin film transistor).
A disk having red, green, and blue filters attached thereto is set in front of the light source, and a display on the TFT-LCD is performed in synchronism with the color change of the illuminating light due to the rotation of the disk, thereby displaying a full color image. There is a display technology. On the other hand, electronic devices other than display devices are also trying to support colorization,
For example, there are an imaging device, a light detection device such as a color sensor, a color copying machine, a color printing plate making device, an image input / output device, an image calculation device, and a lighting device.

[0008] At present, the image pickup device is a charge-coupled device (CCD: C
Harge Coupled Device) is improving its performance with the progress of semiconductor manufacturing technology, and is forming a large market. In particular, its use in video cameras has greatly contributed to the expansion of the home use market.

In the past, color sensors have been used only for limited industrial applications, but have recently been mounted for adjusting the white balance of video cameras, and demand has been rapidly increasing.

[0010] These electronic devices have a structure in which a color filter made of a synthetic resin material or the like is mounted on the front surface of a photoelectric conversion surface, and by detecting characteristics of a specific wavelength component of light incident on the photoelectric conversion element, It has a structure for calculating the characteristics of the entire incident light.

An important point in the structure of an electronic device having such a photoelectric conversion element is the structure of the color filter. Like the display device described above, red (R), green (G), and blue ( Filters corresponding to the wavelength components of light B) are arranged in parallel on the photoelectric conversion surface. That is, the three filters of red, green and blue constitute one pixel on the display.

In addition to the above-described separation of the incident light into three primary color components, a configuration in which only complementary color filters (cyan, magenta, and yellow) or a mixture of these three primary color filters is arranged in parallel has been proposed. ing.

In a copying machine, a copy original is irradiated with white light, and the reflected light is switched by using a mechanical structure in time sequence of the red, green and blue filters, so that the three primary colors of the photosensitive drum are applied to the photosensitive drum. Optical images are written, and then these optical images are transferred to recording paper a plurality of times using a color developer as a medium to reproduce a full-color display. In this principle, the original is irradiated with light sources of three primary colors in advance using red, green, and blue color filters in advance, and the original image is separated into three primary colors. , Full-color copying is possible. In this case, the time-sequential switching control of the color filters is usually performed mechanically.

In a digital copying machine, a configuration is used in which a document image of a copy document is photoelectrically converted by a solid-state image pickup device (CCD), and then digital image signal processing is performed to reproduce a color original image. The solid-state imaging device used in this case is the same as the CCD, and the operation principle is in accordance with the above description.

[0015]

As described above, colorization is one of the current development trends in various display devices, image pickup devices, image input / output devices such as color sensors and copiers. Current color technology has many problems to be solved.

That is, with respect to the display device, there is known a structure in which, for example, a red, green, and blue micro color filter is provided for each display pixel on the front surface of a liquid crystal display device for displaying black and white for the purpose of realizing multi-color or full color. Have been. In such a panel structure, a plurality of light micro color filters are combined into one display pixel.
A reduction in resolution occurs. In order to prevent this, when the display pixel size of the liquid crystal display device for performing display is reduced, the resistance is increased due to the reduction in the size of the electrode portion through which the signal for display flows, and the position where the signal is supplied in the liquid crystal display device The image density displayed between the position and the position distant from the signal supply position will be uneven. In addition, it is necessary to set the manufacturing environment to an extremely high degree of cleanliness, which causes problems such as a decrease in the manufacturing yield due to the influence of dust and the like.

On the other hand, in a display device using the GH (guest host) mode described above, a technique using a dye that absorbs a part of the wavelength of visible light when realizing multi-color display or full-color display is known. In such a case, it is necessary to stack and overlap guest-host liquid crystals to which different kinds of dyes are added, but this technique has a problem that the display picture elements of each layer do not match when viewed from an oblique direction due to parallax. Have. In order to solve this problem, a technique of reducing the thickness of the glass substrate of each laminated panel is conceivable, but in this case, the glass substrate is extremely easily damaged in the process of manufacturing the liquid crystal display device, and handling is difficult. The problem that becomes. Further, in a guest-host liquid crystal using a dye capable of displaying black, it is necessary to use a micro color filter as described above, and in this case, there is a basic problem that the resolution is reduced.

On the other hand, in a technique in which red, green, and blue lights are sequentially switched over and applied to a display device, one pixel of the display device becomes a display pixel as it is in comparison with the case where the micro color filter is used. For this reason, the resolution is improved. However, conventionally, the color switching is realized by a mechanical structure such as attaching the three color filters to the disk in the same direction and rotating the disk. For,
There is a problem in miniaturization and durability of the device, and a problem of generating noise.

On the other hand, the imaging device and the color sensor have the same problem as the display device in that the resolution is reduced due to the structure provided with the micro color filter. There is a problem that the structure of the device becomes complicated in terms of use and the like.

In the above-described color copying machine, the light irradiated on the original or the reflected light from the original is
The switching operation of the filter for separating into three colors is performed mechanically as described above, or it is necessary to provide a light source for each color. And other problems.
Alternatively, when a light source is provided for each color, there are problems in miniaturization of the configuration, life of the light source, color purity, and power consumption.

An object of the present invention is to realize, in liquid crystal, a color tunable filter capable of electrically switching transmission light and irradiation light in a desired wavelength band in a short time in view of various problems of the color technology at the present stage. Accordingly, it is an object of the present invention to provide a light modulation element capable of achieving a downsizing of a configuration and an improvement in display quality, and furthermore, a light which is a novel color electronic device having the above characteristics using such a light modulation element. Detecting device, color copier, color printing plate making device, image input / output device,
An image processing device and a lighting device are provided.

[0022]

SUMMARY OF THE INVENTION The present invention is a light modulation device comprising a plurality of liquid crystal panels having a liquid crystal sealed between a pair of transparent electrodes, between a pair of polarizing plates. , So that only the light of wavelength λ0 is transmitted, Δnd / λ0 = (2m−1) / 2, m ≧ 1 with respect to the refractive index anisotropy Δn of the liquid crystal, the layer thickness d of the liquid crystal, and an integer m. The liquid crystal panel is provided with retardation changing means for changing the retardation Δnd of each liquid crystal panel, and the polarization axis of the polarizer on the incident side and the liquid crystal molecules on the incident side of the liquid crystal panel adjacent to the polarizer. And the angle between the liquid crystal molecules on the incident side of each adjacent liquid crystal panel is 2α,
A light modulating element, wherein the polarization direction of the linear polarization component of the light emitted from the final liquid crystal panel or the polarization axis of the polarizing plate on the emission side is selected in parallel with the major axis direction of the elliptically polarized light component. It is.

[0023]

[0024]

[0025]

[0026]

[0027]

Further, according to the present invention, display is performed by irradiating light from one light source including a plurality of color wavelengths to a transmission type or reflection type display means and a light modulation element, and performing the display within the period of the afterimage effect. The image corresponding to the plurality of colors is displayed by the display means, and for each display period of the image for each color, the color of the light transmitted by the light modulation element is switched, and the light modulation element is between a pair of polarizing plates.
A light modulating element comprising a plurality of liquid crystal panels in which liquid crystal is sealed between a pair of transparent electrodes, wherein each liquid crystal panel transmits a liquid crystal having a refractive index anisotropy Δn, so as to transmit only light having a wavelength λ0. The retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2, m ≧ 1 with respect to the liquid crystal layer thickness d and the integer m, and changes the retardation Δnd of each liquid crystal panel. When the angle between the polarization axis of the polarizing plate on the incident side and the liquid crystal molecules on the incident side of the liquid crystal panel adjacent to the polarizing plate is α, the liquid crystal on the incident side of each adjacent liquid crystal panel is provided. The angle between the molecules is 2α,
A display device, wherein the polarization direction of the linearly polarized light component of the light emitted from the liquid crystal panel in the final stage, or the polarization axis of the polarizing plate on the emission side is selected in parallel with the major axis direction of the elliptically polarized light component. is there.

Further, according to the present invention, a light modulating element is arranged on an incident side of a light detecting means for outputting a detection signal corresponding to an incident light intensity, and the light modulating element is provided between a pair of polarizing plates and between a pair of transparent electrodes. A light modulation element comprising a plurality of liquid crystal panels with liquid crystal sealed therein, each liquid crystal panel having a refractive index anisotropy Δn of the liquid crystal and a layer thickness d of the liquid crystal so as to transmit only light of wavelength λ0. And the integer m, the retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2 and m ≧ 1, and the retardation changing means for changing the retardation Δnd of each liquid crystal panel respectively. When an angle between the polarization axis of the polarizing plate on the incident side and the liquid crystal molecules on the incident side of the liquid crystal panel adjacent to the polarizing plate is α, the angle between the liquid crystal molecules on the incident side of each adjacent liquid crystal panel Is 2α,
A photodetector characterized in that the polarization direction of the polarizing plate on the emission side is selected in parallel with the polarization direction of the linearly polarized light component of the emitted light of the final stage liquid crystal panel, or in parallel with the major axis direction of the elliptically polarized light component. It is.

According to the present invention, there is provided a light source for generating light including wavelengths of a plurality of colors, an original, and a photoelectric conversion means for forming an optical image of the original and converting the optical image into an electric signal. A color image forming means for arranging one light modulation element and forming a color image on a recording medium using the developer for each of the plurality of colors based on an electric signal obtained by the photoelectric conversion means. , The light modulation element is between a pair of polarizing plates,
A light modulating element comprising a plurality of liquid crystal panels in which liquid crystal is sealed between a pair of transparent electrodes, wherein each liquid crystal panel transmits a liquid crystal having a refractive index anisotropy Δn, so as to transmit only light having a wavelength λ0. The retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2, m ≧ 1 with respect to the liquid crystal layer thickness d and the integer m, and changes the retardation Δnd of each liquid crystal panel. When the angle between the polarization axis of the polarizing plate on the incident side and the liquid crystal molecules on the incident side of the liquid crystal panel adjacent to the polarizing plate is α, the liquid crystal on the incident side of each adjacent liquid crystal panel is provided. The angle between the molecules is 2α,
A color copier characterized in that the polarization direction of the polarizing plate on the emission side is selected in parallel with the polarization direction of the linearly polarized light component of the light emitted from the final liquid crystal panel or the major axis direction of the elliptically polarized light component. It is.

According to the present invention, there is provided a light source for generating light including wavelengths of a plurality of colors, an original, and a photoelectric conversion means for forming an optical image of the original and converting the optical image into an electric signal. A plate material processing means for arranging one light modulation element and forming a document image for each color on a plurality of color plate materials to be a printing plate based on an electric signal obtained from the photoelectric conversion means; The light modulation element is a light modulation element including a plurality of liquid crystal panels in which liquid crystal is sealed between a pair of transparent electrodes, between a pair of polarizers, and each liquid crystal panel emits only light of wavelength λ0. For transmission, the retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2 and m ≧ 1 with respect to the refractive index anisotropy Δn of the liquid crystal, the layer thickness d of the liquid crystal, and an integer m. And changing the retardation Δnd of each liquid crystal panel. When the angle between the polarization axis of the polarizing plate on the incident side and the liquid crystal molecules on the incident side of the liquid crystal panel adjacent to the polarizing plate is α, the liquid crystal on the incident side of each adjacent liquid crystal panel is provided. The angle between the molecules is 2α,
A printing plate making apparatus, wherein the polarization direction of the polarizing plate on the emission side is selected in parallel with the polarization direction of the linearly polarized light component of the light emitted from the final liquid crystal panel or the major axis direction of the elliptically polarized light component. It is.

Further, according to the present invention, an object is imaged for each of a plurality of colors by an image pickup means via an optical modulation element, and image data from the image pickup means is stored in an image memory for each color to input a color image. Or, based on the image data for each of a plurality of colors stored in the image memory, display the image on the display means, and output a color image by switching the color of the transmitted light by the light modulation element, The light modulating element is a light modulating element comprising a plurality of liquid crystal panels in which liquid crystal is sealed between a pair of polarizing plates and a pair of transparent electrodes, and each liquid crystal panel transmits only light of wavelength λ0. The retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2 and m ≧ 1 with respect to the refractive index anisotropy Δn of the liquid crystal, the layer thickness d of the liquid crystal, and an integer m, The retardation Δnd of each liquid crystal panel When the angle between the polarization axis of the polarizer on the incident side and the liquid crystal molecules on the incident side of the liquid crystal panel adjacent to the polarizer is α, the incident angle of each of the adjacent liquid crystal panels is provided. The angle between the liquid crystal molecules on the side is 2α,
Image input / output characterized in that the polarization axis of the polarizing plate on the emission side is selected in parallel with the polarization direction of the linearly polarized light component of the light emitted from the final stage liquid crystal panel or the major axis direction of the elliptically polarized light component. Output device.

Also, the present invention provides a light source that generates light of a plurality of wavelengths, a light modulation element that transmits only a specific wavelength component of light from the light source, and a light of one specific wavelength component corresponding to a display image. A plurality of transmissive or reflective display elements that transmit or reflect and transmit or reflect the light of the remaining wavelength components are provided, and the light modulation element encloses liquid crystal between a pair of polarizers and between a pair of transparent electrodes. A liquid crystal panel having a plurality of liquid crystal panels interposed therebetween, each liquid crystal panel having a refractive index anisotropy Δn of the liquid crystal, a layer thickness d of the liquid crystal, and an integer m so as to transmit only light of wavelength λ0. On the other hand, the retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2 and m ≧ 1, and the liquid crystal panel includes retardation changing means for changing the retardation Δnd of each liquid crystal panel. Polarization axis of the polarizing plate When the angle between the liquid crystal molecules on the incident side of the liquid crystal panel adjacent to the polarizing plate and alpha, the angle between the liquid crystal molecules on the incident side of each adjacent liquid crystal panel is 2.alpha,
An image processing apparatus, wherein the polarization direction of the linear polarization component of the light emitted from the liquid crystal panel at the final stage or the polarization axis of the polarizing plate on the emission side is selected in parallel with the major axis direction of the elliptically polarized light component. It is.

Further, according to the present invention, light from a light source that emits light containing wavelengths of a plurality of colors is irradiated as one of the lights of the plurality of colors via a light modulation element. A liquid crystal panel in which liquid crystal is sealed between a pair of transparent electrodes, between the polarizers, and each liquid crystal panel refracts the liquid crystal so as to transmit only light of wavelength λ0. The retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2, m ≧ 1 with respect to the ratio anisotropy Δn, the layer thickness d of the liquid crystal, and the integer m, and the retardation of each liquid crystal panel is selected. The liquid crystal panel is provided with a retardation changing means for changing the phase difference Δnd, and when an angle between the polarization axis of the polarizing plate on the incident side and the liquid crystal molecules on the incident side of the liquid crystal panel adjacent to the polarizing plate is α, each liquid crystal adjacent to the polarizing plate The gap between the liquid crystal molecules on the entrance side of the panel The angle is 2α,
The illumination device, wherein the polarization direction of the linear polarization component of the light emitted from the final stage liquid crystal panel or the polarization axis of the polarizing plate on the emission side is selected in parallel with the major axis direction of the elliptically polarized light component. is there.

[0035]

According to the present invention, light enters from one of the polarizing plates of the light modulation element, and the light passing through the polarizing plate is converted into linearly polarized light. When the linearly polarized light passes through a plurality of liquid crystal panels, the linearly polarized light sequentially turns at an angle depending on the wavelength and the degree of birefringence due to the birefringence of each liquid crystal panel. The birefringence of the liquid crystal panel has wavelength dependence, and the angle at which the linearly polarized light that has passed through the polarizing plate turns every time it passes through the liquid crystal panel is different for each wavelength.

On the other hand, a polarizing plate is arranged on the emission side of the liquid crystal panel in the last stage. When the retardation of the liquid crystal of each liquid crystal panel is changed by the retardation changing means,
Correspondingly, of the light emitted from the last-stage liquid crystal panel, the wavelength of the light in which the polarization direction of the linearly polarized light component or the major axis direction of the elliptically polarized light component is parallel to the polarization axis of the other polarizing plate. It can be selected as appropriate. Thus, light of any color can be transmitted by the light modulation element.

By combining such a light modulation element with a transmission type or reflection type display means, the light modulation element selectively transmits light of a plurality of wavelengths, and within the period of the afterimage effect of human beings, the light modulation element is used. Are displayed on the display means. Thereby, a color display device can be configured. In addition, in an arbitrary color electronic device using light of a plurality of wavelengths, not limited to a display device, by using the light modulating element as a component that generates the light of a plurality of colors, the display device is small and lightweight, A color electronic device with significantly improved quality can be realized. When the driving voltage applied to the liquid crystal panel is switched between a plurality of different states by using the switching means, the liquid crystal panel and the light modulating element composed of a polarizing plate provided on at least one side thereof are mutually switched. In this case, light of a different wavelength can be transmitted, or light of an arbitrary wavelength can be transmitted. Therefore, it is possible to switch whether or not to transmit light having a wavelength corresponding to the color on the upstream side of the light modulation element in the light passing direction, and it is possible to obtain a color and a color obtained by mixing these colors and an achromatic color. . With such a simplified and miniaturized configuration, the photodetector, the color copier,
A color printing plate making device, an image input / output device, an image calculation device, and a lighting device can be realized. In the light detecting device, such a light modulating element is combined with light detecting means,
In a color copying machine, a light source, a document, and a photoelectric conversion unit are combined. In a printing plate making apparatus, a light source, a document, and a photoelectric conversion unit are combined. In an image input / output device, an imaging unit and a display unit are combined. In an image processing device, a light source and a plurality of transmissive or reflective display elements are combined, and in an illumination device, the light modulator selectively transmits light of a plurality of wavelengths by combining with a light source. I do. Thus, in the present invention, in a color electronic device that uses light of a plurality of wavelengths of light, by using the light modulation element as a component that generates the light of the plurality of colors, the display quality is remarkably small and light. An improved color electronic device can be realized.

[0038]

FIG. 1 is an exploded perspective view showing a configuration example of a light modulation element 1 according to one embodiment of the present invention, FIG. 2 is a view showing the structure of the light modulation element 1, and FIG. FIG. 2 is a diagram illustrating an optical configuration of No. 1. The light modulating element 1 has a plurality of liquid crystal panels Pi (where i =
1 to N) are stacked, and polarizing plates 2 and 3 are arranged on both sides in the arrangement direction. Each liquid crystal panel Pi
The applied voltages are individually controlled by a plurality of voltage adjustment circuits 5 commonly connected to the power supply 4. As a modification, a common applied voltage may be applied from the common voltage adjustment circuit 5 to each liquid crystal panel Pi.

Each of the liquid crystal panels Pi has the same configuration.
(Indium tin oxide) transparent electrodes 8, 9
Are respectively formed. The transparent electrodes 8 and 9 are respectively coated to form alignment films 10 and 11 made of polyvinyl alcohol or the like, for example.
A liquid crystal 12 having a birefringence such as (manufactured by Merck) is sealed with a cell thickness d = 2.5 μm, and the periphery is sealed with a sealing material 13. The alignment films 10 and 11 of each liquid crystal panel Pi are respectively subjected to an alignment process such as a rubbing process.
In each liquid crystal panel Pi, as shown in FIG. 2 (2), the orientation directions of the light incident side and the light emitting side are parallel to each other,
Indicated by arrows Ai (i = 1 to N).

Hereinafter, reference will be made to FIG. 1 and FIG. With respect to the polarization direction B1 of the polarizing plate 2, the alignment direction A1 of the liquid crystal panel P1 closest to the polarizing plate 2 has an angle α (for example, 15 degrees).
Degree) selected to intersect. The alignment direction A2 of the liquid crystal panel P2 adjacent to the liquid crystal panel P1 is the same as the polarization direction B1.
And a direction inclined by an angle 3α. Similarly, the orientation direction AN of the N-th liquid crystal panel PN is selected to be a direction inclined by an angle (2N−1) α with respect to the polarization direction B1. The polarization direction of the polarizing plate 3 on the exit side of the liquid crystal panel PN in the final stage is selected to be inclined at an angle of 2Nα with respect to the polarization direction B1 of the polarizing plate 2. In other words, the angle between the liquid crystal molecules on the incident side of the adjacent liquid crystal panels P1, P2,..., PN is 2α. The liquid crystal molecules on the incident side of the liquid crystal panels P1, P2,..., PN have the rubbing directions in which the alignment films 10 and 11 in each liquid crystal panel Pi have been subjected to the alignment treatment. Is as described above.

That is, the polarization direction B1 of the polarizing plate 2 and the alignment direction A1 of the liquid crystal panel P1 form an angle α, and the alignment directions Ai, of the adjacent liquid crystal panels Pi and Pi + 1 (i = 1 to N-1). Ai + 1 is determined so as to be sequentially inclined by the angle 2α in the same direction. Further, the polarization direction B2 of the polarizing plate 3 is selected to be a direction inclined by an angle α in the same direction as the alignment direction AN of the liquid crystal panel PN in the last stage.

FIG. 4 is a view for explaining the behavior when light that has passed through the polarizing plate 2 and has become linearly polarized light has passed through the liquid crystal panel P1. As shown in FIG. 4A, light incident on the polarizing plate 2 is linearly polarized light parallel to the polarization direction B1 at any wavelength, and is incident on the liquid crystal panel P1. LCD panel P
The 1 orientation direction A1 intersects the polarization direction B1 by an angle α. Here, the retardation Δn of the liquid crystal panel P1
d (Δn: refractive index anisotropy of liquid crystal, layer thickness of d liquid crystal 12) and wavelength λ0 of incident light are

[0043]

(Equation 1)

In the relationship described above, the light having the wavelength λ0 transmitted through the liquid crystal panel P1 becomes a linearly polarized light rotated by the angle 2α from the polarization direction B1 due to the birefringence of the liquid crystal 12. The direction of the optical axis of the liquid crystal panel P1 on the emission side of the light of wavelength λ0 that satisfies Equation 1 is indicated by an arrow C1 in FIG.
Indicated by Hereinafter, of the light emitted from the liquid crystal panel Pi, the optical axis direction of the light emitted as linearly polarized light that satisfies Equation 1 is indicated by an arrow Ci. This phenomenon is explained as follows. That is, as shown in FIG.
As shown in FIG. 4 (2), the linearly polarized light
It is linearly polarized light near the incident side end of the liquid crystal panel P1, but is sequentially converted into elliptically polarized light, circularly polarized light, and elliptically polarized light as it passes through the liquid crystal panel P1, and becomes linearly polarized again near the exit side end. The optical axis direction of the linearly polarized light on the emission side is shifted by an angle 2α with respect to the polarization direction B1 of the polarizing plate 2.

As described above, when the light of wavelength λ0 emitted as linearly polarized light from the liquid crystal panel P1 is incident on the liquid crystal panel P2, if the above equation 1 is satisfied with respect to the liquid crystal panel P2, the wavelength λ0 is again output from the liquid crystal panel P2. Is emitted as linearly polarized light. The optical axis direction C2 shown in FIG.
It turns by an angle 2α from C1, which is the optical axis direction of the light incident on the liquid crystal panel P2. That is, the polarizer 2 rotates by 4α from the polarization direction B1. Similarly, if all the liquid crystal panels Pi up to the N-th liquid crystal panel PN at the last stage are selected so as to satisfy Equation 1,
Wavelength λ0 emitted as linearly polarized light from liquid crystal panel PN
Is turned from the polarization direction B1 of the polarizing plate 2 by an angle 2Nα. Therefore, by selecting the polarization direction B2 of the polarizing plate 3 in the same direction as the optical axis direction of the light having the wavelength λ0 at this time, the light having the wavelength λ0 is transmitted through the polarizing plate 3.

On the other hand, the polarizing plate 2 emits light of an arbitrary wavelength as linearly polarized light.
n has a wavelength dependency as shown by a line 14 in FIG.

That is, light having a wavelength other than the wavelength λ0 becomes circularly polarized light or elliptically polarized light when emitted from the liquid crystal panel P1, and is transmitted by the polarizing plate 3 more than the light having the wavelength λ0 when passing through the polarizing plate 3. The rate of absorption or dispersion is significantly increased. Therefore, the light emitted from the polarizing plate 3 has a distribution state having a maximum value at the wavelength λ, as shown in a line 15 in FIG. 6, which is a graph showing the relationship between the wavelength λ of the emitted light and the transmitted light intensity I. Is shown. On the other hand, lines 15, 16, and 17 in FIG. 6 are obtained when the number of liquid crystal panels Pi to be laminated in the light modulation element 1 shown in FIG. 1 is N1, N2, and N3 (N1>N2> N3). It is a graph. That is, according to the experiment of the present inventors, the polarizing plate 3
The noise light intensities I1, I2, and I3, which are the intensities of the light having wavelengths other than the wavelength λ0, of the light emitted from the liquid crystal panel P and the half-widths W1, W2, and W3 of the lines 15 to 17 are expressed by the liquid crystal panel P.
i can be decreased as the number N of stacked layers increases,
It was confirmed that the color purity of light emitted from the polarizing plate 3 could be improved.

Further, the apparent refractive index anisotropy Δn of the liquid crystal 12 has a characteristic that varies with the voltage V applied between the transparent electrodes 8 and 9 as shown by the line 18 in FIG. Are known. Therefore, in FIG. 5, when light of wavelength λ0 is to be obtained, the required refractive index anisotropy is Δn0 from the line 14, and the refractive index anisotropy Δn0
In order to obtain 0, the voltage V0 needs to be applied from the line 18 in FIG. In this way, by appropriately adjusting the voltage value applied to each liquid crystal panel Pi via the voltage adjustment circuit 5, light of any wavelength can be obtained from the light modulation element 1.

Actually, when it is desired to obtain the desired wavelength and the desired color purity for the light, that is, FIG.
Wavelength λ giving the maximum value of the distribution curve of the transmitted light intensity at
, The half-value width W and the noise light intensity I are appropriately determined, the retardation of the liquid crystal panel Pi,
The number can be determined by comprehensively considering the number of layers, the refractive index of the liquid crystal 12, the wavelength characteristics of the polarizing plates 2 and 3, and the like.

The present inventor measures the distribution of transmitted light intensity by changing the voltage applied to each liquid crystal panel Pi using the voltage adjusting circuit 5 for the light modulation element 1 having the above-described configuration. did. The measurement results are shown in the graph of FIG. Lines 19, 20, and 21 in FIG. 8 indicate that the applied voltages V1, V2, and V3 are

[0051]

## EQU2 ## The case where V1 <V2 <V3 is satisfied. That is, lines 19 to 21 show that red, green, and blue transmitted light can be obtained with relatively good color purity, respectively.

As a modification of the present invention, the distance between the liquid crystal panels (P
Between i and Pi + 1, a polarizer is installed at 1 ≦ i ≦ N−1), and the polarization direction of the polarizer is determined by the wavelength λ0 of interest.
That is, it is also possible to realize this by setting each liquid crystal panel Pi parallel to the long axis direction (Ci) of linearly polarized light or elliptically polarized light close to linearly polarized light. At this time, the light of the wavelength λ0 of interest can pass through the light modulation element 1 according to the above-described operation principle, but the light of other wavelengths is circularly polarized or the major axis is not parallel to the polarization direction of the intermediate polarizer. The elliptically polarized light is prevented from passing therethrough. Therefore, the light modulation element 1 that can efficiently extract desired light can be configured. In addition to the birefringence of the liquid crystal 12 of each liquid crystal panel Pi, in addition to the birefringence in the above-described embodiment, even if the liquid crystal molecules are twisted to increase the optical rotation characteristic, light of an arbitrary wavelength is extracted according to the same principle as described above. The light modulation element which can perform it can be comprised. That is, by twisting the liquid crystal molecules, light incident on each liquid crystal panel Pi in a state of linearly polarized light becomes elliptically polarized light having a certain eccentricity when emitted. By appropriately selecting the twist angle and the like, elliptically polarized light as close as possible to linearly polarized light can be obtained. In this respect, the modification can be realized.

For example, when such a light modulation element 1 is combined with an active matrix liquid crystal display device for monochrome display to perform multi-color or full-color display, a high-speed color change is required in the application. Will be done. In order to operate the light modulation element 1 at a high speed, the liquid crystal molecules must be displaced at a high speed corresponding to a predetermined change in the applied voltage. For this reason, it is necessary to make the layer thickness d of the liquid crystal 12 as small as possible. For this reason, in Equation 1, when m = 1 is defined and deformed,

[0054]

## EQU3 ## Δnd = λ0 / 2 is obtained. If λ0 = 650 nm is determined here, Δnd = 0.32 μm from Expression 3. Assuming that the refractive index anisotropy Δn of a normal nematic liquid crystal is Δn = 0.13, the layer thickness d becomes 2.5 μm. Given that the layer thickness of the liquid crystal in the ordinary TN type liquid crystal display device is 5 to 12 μm, in this case, the layer thickness of the liquid crystal 12 is 1/5 to 1/2 smaller than that of the existing liquid crystal display device. Becomes It is known that the response speed corresponding to the change in the applied voltage of the liquid crystal is generally inversely proportional to d ² with respect to the thickness d of the liquid crystal. That is, the relationship between the layer thickness d and the response time τ is represented by the line 2 in FIG.
As shown in FIG. That is, the response time becomes faster as the cell thickness becomes smaller. Under the actual numerical conditions as described above,
4 to 4 times faster than the response speed of a normal TN type liquid crystal display device
This means that the response is 25 times faster.

On the other hand, among the currently sold liquid crystal display devices, the minimum value of the layer thickness of the liquid crystal 12 is about 5 μm. It can be seen that the refractive index anisotropy of the liquid crystal material needs to be Δn = 0.07 or more. This value is the same as the normal T
The refractive index anisotropy of the N-type liquid crystal is a numerical value that satisfies, and therefore, the light modulation element 1 of the present embodiment can be configured using a normal TN liquid crystal.

On the other hand, in order to obtain a high response speed,
It is also necessary to consider the viscosity of the liquid crystal material. It is desirable that the viscosity of the liquid crystal is as low as possible. Generally, if the viscosity is 35 centipoise (cp) or less, the effect of realizing the present invention is exhibited. Obviously made by experience. Biphenyl compounds, phenyl ester compounds, cyclohexane compounds, phenylpyrimidine compounds, dioxane compounds, tolan compounds, alkenyl compounds, fluorinated compounds, and the like are suitable for the liquid crystal material exhibiting such characteristics. Is effective.

Using the liquid crystal composition made of such a material, the light modulation element shown in FIG. 1 was constructed, and the applied voltage was switched so as to obtain three wavelengths λ1, λ2, λ3 as shown in FIG. As a result of measuring the response speed, a high-speed response of several milliseconds was obtained. That is, one field period of 1/60 second of the NTSC television video signal is about 17 msec. Therefore, as an example, it is possible to realize a configuration in which a red image, a green image and a blue image are displayed every 5 msec in one field period, and in synchronization therewith, the light modulation element 1 switches so as to transmit red, green and blue light. Becomes As a result, multi-color or full-color display using the light modulation element 1 becomes possible. That is, it is possible to realize a color filter that is small and lightweight and has a simple configuration.

FIG. 10 shows a light modulation device 1 according to a modification of the present invention.
It is a block diagram which shows the structure of a. In the present embodiment, the driving voltages applied to the plurality of liquid crystal panels P1 to PN are the outputs of the high-frequency power supply 23 that generates a relatively high frequency fH and the low-frequency power supply 24 that generates a relatively low frequency fL. The output is appropriately selected by the switching circuit 25, and the selected output is adjusted by the voltage adjusting circuit 5 as in the above-described embodiment.
i.

That is, as the liquid crystal used for each liquid crystal panel Pi, a two-frequency driving liquid crystal having a positive dielectric anisotropy Δε at a relatively low frequency voltage and a negative dielectric anisotropy Δε at a high frequency voltage is used. I have to. That is, when the driving voltage from the low frequency power supply 24 is adjusted by the voltage adjusting circuit 5 and supplied to each liquid crystal panel Pi, the liquid crystal of each liquid crystal panel Pi changes from a homogeneous arrangement to a homeotropic arrangement gradually as the applied voltage increases. In response to this change, the refractive index anisotropy Δn changes. When returning to the first homogeneous arrangement from this state, the driving voltage from the high frequency power supply 23 is used, and the voltage is adjusted to an appropriate voltage by the voltage adjustment circuit 5.
As a result, the return is performed at high speed, and the operation of the light modulation element 1a can be performed at high speed.

The two-frequency driving liquid crystal is selected from the group consisting of alkoxyphenylcyclohexylcarboxylate, alkylphenylcycloxycarboxylate, alkoxyphenylcyclohexane and the like in order to broaden the effective operating temperature range of the liquid crystal and to realize low viscosity. The liquid crystal that becomes the base material is composed of a material with relatively weak polarity.

[0061]

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[0062]

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[0063]

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[0064]

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A material having a low dielectric dispersion frequency, such as, for example, is added. Furthermore, using a material having a large negative dielectric anisotropy Δε, such as the following 2,3-dicyano 1,4-hydroquinone derivative, the overall dielectric anisotropy and cutoff frequency (that is, dielectric anisotropy) are used. (The frequency at which Δε switches between positive and negative).

[0066]

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[0067]

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[0068]

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In the above-described embodiment, the number N of the liquid crystal panels Pi constituting the light modulation elements 1 and 1a is not limited at all, and the light having a desired wavelength obtained by using the light modulation elements 1 and 1a is not limited. Is appropriately selected in consideration of the color purity and the like. In addition, the type and number of the polarizing plates (2, 3), the type of liquid crystal material, the condition of the layer thickness d of the liquid crystal 12, the installation condition of each liquid crystal panel Pi and the polarizing plates 2, 3 and the like are appropriately selected.

As a liquid crystal material, a liquid crystal material having a negative dielectric anisotropy Δε, such as a nematic liquid crystal, and a liquid crystal panel composed of a surface treatment agent of a vertical alignment system, or a ferroelectric liquid crystal is used. Also achieves the same effect. In each of the embodiments, a glass substrate is used as the substrate of the light modulation elements 1 and 1a. However, as a modified example, the weight can be reduced by replacing the substrate with a plastic substrate made of a synthetic resin. Further, for the purpose of correcting the wavelength characteristics of transmitted light, a retardation plate made of a polymer film such as polycarbonate or polyvinyl alcohol is used.
A configuration further provided between the polarizing plates 2 and 3 or a material obtained by adding a predetermined dichroic dye to a liquid crystal material may be used.

Hereinafter, examples of application to various electronic devices equipped with the light modulation elements 1 and 1a will be described.

FIG. 11 is an exploded perspective view of a liquid crystal display device 26 as an embodiment of an electronic device, and FIG. 12 is a block diagram showing an electrical configuration of the liquid crystal display device 26. In this figure, the liquid crystal display device 26 includes a back light source 27 for generating white light as a surface light source and a non-linear switching element (thin film transistor, metal-insulating film-metal structure switching element, etc.) for performing monochrome display at high speed. It is configured to include an adaptive active matrix type liquid crystal display element 28 and a liquid crystal color filter 29 as an application example of the light modulation elements 1 and 1a described in the above embodiments.

The composite video signal supplied to the liquid crystal display device 26 is separated from the synchronizing signal SY by the synchronizing separation circuit 30 and the remaining color signal SC is input to the color demodulation circuit 31 to correspond to red, green and blue. Image signals SR, SG,
SB are output respectively. Image signals SR, S for each color
G and SB are sequentially selected by the switching circuit 32,
It is input to the display control unit 33. The display control unit 33 scans the liquid crystal display element 28 and outputs image signals SR to SB for each color.
Is displayed in monochrome.

On the other hand, the synchronization signal SY is input to the control circuit 34, and the control circuit 34 controls the switching circuit 32 to output the synchronization signal SY.
And the liquid crystal panels P1 to PN
The liquid crystal color filter 29 is synchronized so as to sequentially transmit red, green and blue light corresponding to monochrome display for each color displayed on the liquid crystal display element 28 by controlling the voltage adjusting circuit 5 connected to the To switch. Here, one field period of the NTSC composite video signal is 1/60 second, that is, about 17 msec. During this one field period, monochrome images corresponding to red, green and blue images are displayed on the liquid crystal display element 28. When the images are sequentially displayed, the liquid crystal color filter 29 can perform color switching at high speed in synchronization with this, as described above. In this manner, the liquid crystal display device 26 that performs multi-color display or full-color display using the liquid crystal color filter 29 of the present invention can be realized.

Therefore, in the liquid crystal display device 26 according to the present embodiment, the resolution is effectively three times or more as compared with the configuration using the conventional micro color filter, and the display quality is remarkably improved. The simplification of the manufacturing process in that no micro color filter with a fine structure is formed,
The yield can be improved and the configuration can be simplified.

FIG. 13 is a system diagram of a projection type display device 35 as another embodiment of the electronic device of the present invention. The projection display device 35 includes, for example, a light source 36 that generates white light,
An ultraviolet blocking filter 37 and the liquid crystal color filter 2
9 and a lens 38 are arranged on the same optical axis, and the liquid crystal display element 28 and the lens 39 are arranged on the optical axis,
The optical image is projected on the screen 40 and displayed. In such a projection display device 35, conventionally, for example, a disk that is mechanically driven to rotate is disposed between the ultraviolet blocking filter 37 and the lens 38, and the disk is arranged in the circumferential direction.
This is a mechanical color filter in which red, green and blue color filters are formed. Compared with such a configuration, in the present embodiment, no mechanical driving parts are required, so that the durability is improved, and noise can be reduced, the life can be extended, and the configuration can be reduced in size.

FIG. 14 is a block diagram of a color image pickup device 41 as another embodiment of the electronic device of the present invention. The color imaging device 41 of the present embodiment includes a solid-state imaging device 42 including the CCD device and the like, and the liquid crystal color filter 29 is mounted on the light incident side of the solid-state imaging device 42. The control circuit 43 controls the scanning circuit 44 to scan the solid-state imaging device 42 in a raster manner. In addition, the voltage control circuit 5 is controlled for each scan of one screen of the solid-state imaging device 42 so as to control the liquid crystal color filter 29 to sequentially transmit, for example, red, green, and blue light. Accordingly, image signals corresponding to the red, green, and blue images to be imaged are sequentially read from the solid-state image sensor 42, and each image signal is converted into a digital signal by the analog / digital converter 45, and the control is performed. The signal is read by the circuit 43. The control circuit 43 is connected to a synchronization signal generation circuit 46 for generating a synchronization signal for synchronizing the control of the scanning circuit 44 and the voltage adjustment circuit 5.

As described above, the color image pickup device 41 of the present embodiment eliminates the need to use a micro color filter on the light incident side of the solid-state image pickup device 42 as described in the prior art, and the resolution is substantially 3 ×. More than twice, the image quality is improved. Also, as compared with the case where a micro color filter is mounted, the labor and the configuration in manufacturing are simplified, and the yield is improved.

FIG. 15 is a block diagram of a color sensor 47 as another embodiment of the electronic apparatus of the present invention. The color sensor 47 is used, for example, in a facsimile communication device or the like as a technique for reading a reference white original when performing white balance adjustment. The color sensor 47 includes a p-layer 48, an i-layer 49, and an n-layer 50 of amorphous silicon.
And a transparent electrode 53 made of ITO (indium tin oxide) formed on the p-layer 48 and a glass substrate 54. The sensor main body 55 is provided.

The liquid crystal color filter 29 is disposed on the light incident side of the sensor main body 55. The control circuit 43
The voltage control circuit 5 is controlled to control the liquid crystal color filter 29 to sequentially transmit, for example, red, green, and blue light. Each time the color is switched, the voltage detection circuit 56 detects the voltage between the back electrode 52 and the transparent electrode 53. That is, the transmitted light intensity for each color can be detected.

In such a color sensor 47, conventionally, three color filters of red, green and blue are provided on the sensor body 55, and the back electrode 52 and the transparent electrode 53 are separated for each color filter. is there.
Compared with such a conventional technique, the present embodiment can achieve a simplification of the configuration and a reduction in size.

FIG. 16 is a block diagram of a color copying machine 57 as another embodiment of the electronic apparatus of the present invention. The color copier 57 uses the light source 36 used for reading the original image by irradiating the original 58 with light as a white light source, and disposing the liquid crystal color filter 29 between the light source 36 and the original 58. The reflected light from the original 58 is incident on an image sensor 61 such as the CCD device via a plurality of reflecting mirrors 59 and an optical device 60. That is, the liquid crystal color filter 2
Each time 9 is switched to red, green and blue, the original 58 is scanned, and the image sensor 61 reads an original image corresponding to each color.

The output from the image sensor 61 is
The printing device 62 performs a printing operation a plurality of times on a single recording sheet to perform color copying using a plurality of color developers corresponding to the three colors. At this time, the printing device 62 is configured to include, for example, a laser light generator, a photosensitive drum irradiated with the laser light, or a developing device using the color developer.

Therefore, in such a color copying machine 57, the necessity of using the above-described mechanical structure for switching the color of the light source light emitted to the original 58 is eliminated, and the structure is simplified and the durability is improved. Improvement can be achieved at the same time. As another modified example of the present embodiment, the liquid crystal color filter 29 is installed near the light source 36 instead of the liquid crystal color filter 29 shown in FIG.
As shown by a two-dot chain line in FIG. 6, it may be arranged on the optical path in front of the image sensor 61. Even with such a configuration example, the same effect as the above-described effect can be achieved.

FIG. 17 is a system diagram of the color printing plate making apparatus 63. The plate making device 63 has a halogen lamp 64 as a light source, and the light from the light source is guided into an original cylinder 65 made of glass or the like formed in a straight cylindrical shape, and is transmitted via a reflecting mirror 66 and a condenser lens 67 to the original cylinder. The light is condensed on a color original film 68 mounted on the original document 65. The light transmitted through the color original film 68 is transmitted to the pickup lens 6.
The light is guided to the half mirror 71 through the reflection mirror 9 and the reflection mirror 70. The light reflected by the half mirror 71 enters the photoelectric tube 73 via the green or red filter 72.

On the other hand, the light transmitted through the half mirror 71 is reflected by the reflecting mirror 74, passes through the liquid crystal color filter 29, and enters the photoelectric tube 75. The current corresponding to the amount of incident light from the phototubes 73 and 75 is converted into a voltage by a current / voltage converter 76 and given to a control circuit 77. The control circuit 77 controls a plate making mechanism 78 to perform planographic printing, letterpress printing, intaglio printing and printing. Prepress one of the stencil materials.

In the color plate making apparatus 63 as well, the necessity of providing, for example, red, green and blue filters and a plurality of phototubes corresponding to the filters is eliminated, and the structure can be reduced in size and simplified. .

FIG. 18 is a block diagram of a color facsimile apparatus 79 for transmitting a color image. The color original 58 to be read is a reading element 81 on which the liquid crystal color filter 29 and the line image sensor 80 are stacked.
Is read each time the liquid crystal color filter 29 is switched to three colors. That is, the read processing circuit 82 controls the voltage adjustment circuit 5 to sequentially switch the color of light transmitted through the liquid crystal color filter 29 among the three colors, and the line image sensor 80 is scanned in synchronization with the three colors. The obtained image data for each color is read by the reading processing circuit 82 and the image processing circuit 8
At 3, data compression or data decompression processing is performed.
Alternatively, it is stored in the image memory 84. Color manuscript 58
The image data obtained by reading is transmitted to the communication target by the communication control unit 85 and sent to the telephone line network via the network control unit 86.

On the other hand, image data sent from the telephone line network passes through a network control unit 86 and a communication control unit 85,
The data decompression processing and the like are performed in the image processing circuit 83,
Through the recording processing circuit 87, a color image is recorded on recording paper by a color recording means 88 comprising, for example, a three-color thermal transfer ribbon or a three-color ink jet nozzle. The configuration of such a color facsimile apparatus 79 is as follows.
This is a so-called on-chip system in which the liquid crystal color filter 29 is directly mounted on the line image sensor 80. In such a color facsimile apparatus 79, conventionally, for example, three color micro filters are provided on the line image sensor 80. Therefore, in the present embodiment, the configuration can be reduced in size and simplified with respect to such a conventional example.

FIG. 19 is a system diagram showing a reading element 81a of another configuration example of the color facsimile apparatus 79. In this embodiment, the color original 58 includes, for example, the white light source 36.
From the lens, the reflected light of which is reflected by the rod lens 89,
The light enters the line image sensor 80 via the liquid crystal color filter 29. In such an embodiment, instead of the liquid crystal color filter 29 in the related art, color filters of three colors are translated in a mechanical manner, for example, and the color original 58 is moved.
Was decomposed into three colors. That is, in the present embodiment, simplification of the configuration and downsizing can be achieved with respect to such a conventional example.

FIG. 20 shows the color facsimile apparatus 7.
FIG. 9 is a system diagram showing a reading element 81b of another configuration example 9; In this embodiment, the light from the white light source 36 is time-sequentially separated into three colors via the liquid crystal color filter 29, and the reflected light from the color original 58 is converted into a line image through the rod lens 89. The light enters the sensor 80. That is, also in this embodiment, the same effects as those described in the above-described embodiment can be achieved.

Next, as an example showing that the present invention can be applied to an image processing device, the IEICE Transactions C-
II J73-C-II P. 703-712 (199
The image calculation system described in (0) is cited and described. FIG. 21 is a system diagram showing the configuration of an image calculation device 90 as another embodiment of the present invention. The image processing device 90 includes a white light source 36 and a liquid crystal color filter 29, and the light from the liquid crystal color filter 29 receives a color polarizing plate 91, for example, a liquid crystal display element 92 that performs active matrix monochrome display, and a color polarizing plate. 93, similar liquid crystal display element 9
The light that is incident on the configuration including the color polarizing plate 95 and the color polarizing plate 95 and exits from the color polarizing plate 95 becomes an arithmetic image. Here, the color polarizers 91, 93, and 95 convert light having a predetermined specific wavelength into linearly polarized light, but light having a wavelength other than the specific wavelength is not converted into linearly polarized light as it is. It has the characteristic of passing.

FIG. 22 is a diagram for explaining the operation of the image calculation device 90. FIG. 22A shows an image calculation device 90a that calculates the logical product (G1 · G2) of the display images G1 and G2 of the liquid crystal display elements 92 and 94. In this example, the color polarizers 91, 93, and 95 all convert the light of wavelength λ1 into linearly polarized light in the same direction. Therefore, the color polarizing plate 91
Is transmitted through the liquid crystal display element 92 as an example.
In the non-transmission region indicated by the oblique line, the light is rotated by a predetermined angle, and in the transmission region without the oblique line, the light is transmitted as linearly polarized light. Therefore, the light in the transmissive area passes through the color polarizer 93 as it is, and then the portion corresponding to the non-transmissive area of the liquid crystal display element 94 corresponding to the hatched area is rotated, and the portion corresponding to the transmissive area without the oblique line is applied. Then it is transmitted as it is. When the transmitted light passes through the color polarizing plate 95, the light that has been rotated by the liquid crystal display element 94 is blocked, and the light that has not been rotated is transmitted. The light that has been rotated by the liquid crystal display element 92 is blocked by the color polarizer 93. Accordingly, a semicircular display portion is obtained as the calculation image 96.

FIG. 22 (2) shows the configuration of an image arithmetic unit 90b for realizing the logical sum (G1 + G2) of the display images G1 and G2 as in FIG. 22 (1). The light used is wavelength λ
Light of two wavelengths, 2 and λ3, is used. Here, the color polarizing plate 91 converts only the light of the wavelength λ2 into linearly polarized light, the color polarizing plate 93 converts the light of both the wavelengths λ2 and λ3 into linearly polarized light, and the color polarizing plate 95 converts Wavelength λ
Only light 3 is converted into linearly polarized light. Therefore, the light of wavelength λ2 is transmitted through the color polarizing plate 91 and is converted into linearly polarized light, and the light of wavelength λ3 is transmitted through the color polarizing plate 91 without being converted into linearly polarized light. When the light having the wavelength λ2 is transmitted through the liquid crystal display element 92 and the color polarizer 93, the light is transmitted only through the disc-shaped region of the liquid crystal display element 92 that is not shaded. When the light having the wavelength λ2 is incident on the liquid crystal display element 94, the light is transmitted without rotation in the portion without hatching and is transmitted in the light with rotation in the hatched portion. Since all light of λ2 is transmitted, transmitted light in the shape of the disk-shaped region is obtained.

On the other hand, the light of wavelength λ3 is first converted into linearly polarized light when it passes through the color polarizer 93, and thus passes through the liquid crystal display element 94 and the color polarizer 95, so that the oblique lines in the liquid crystal display element 94 The light in the rectangular area not attached is transmitted. Therefore, as the operation image 96, an image in which the circular image G1 and the rectangular image G2 are superimposed, that is, an image of a logical sum is obtained.

FIG. 22C shows images G1 and G similar to those described above.
It has a configuration of an image calculation device 90c that obtains an inverted image of the inverted image of the exclusive OR of two (G1EXORG2).
At this time, monochromatic light of wavelength λ4 is used, and the color polarizing plate 91,
95 converts the wavelength λ4 into linearly polarized light, while the color polarizing plate 93 transmits light of the wavelength λ4 as it is. That is, the color polarizing plate 93 need not be provided, or may be a transparent glass or the like. The light having the wavelength λ4 is transmitted through the color polarizer 91 and is converted into linearly polarized light. This light is transmitted as it is in a circular area without hatching in the liquid crystal display element 92, and is rotated by a predetermined angle in the hatched area. .

When the light in such a state enters the liquid crystal display element 94, the light incident on the shaded portion of the liquid crystal display element 94 is rotated by a predetermined angle. That is, when transmitted through the liquid crystal display element 92, the rotated light is further rotated to be linearly polarized light parallel to the polarization direction of the color polarizing plate 95. The area where the optical rotation is not performed by the liquid crystal display element 92 is rotated by the hatched portion of the liquid crystal display element 94 and is blocked by the color polarizer 95. A similar phenomenon occurs in the transmissive portion of the liquid crystal display element 94 which is not shaded, and accordingly, FIG.
The inverted image of the exclusive OR image of the images G1 and G2 as shown in FIG.

The image processing devices 90 and 90a to 90a-9
By using a liquid crystal color filter 29 as shown in FIG. 21, any wavelength necessary for the calculation can be easily generated and selected. The present invention can be suitably applied to image processing for deleting a part of an image.

In addition, the optical modulator of the present invention can be used as an optical selector for extracting a desired frequency optical signal from various frequency optical signals mixed in an optical communication apparatus. The light modulation device of the present invention can also be used for an illumination device that selectively extracts light from a light source that generates light including wavelengths of a plurality of colors as one of the lights of the plurality of colors and irradiates the light.

Further, the retardation Δnd of the liquid crystal 12
Is known to change with temperature, and a modified example using a configuration for adjusting the temperature of each liquid crystal panel Pi in place of the voltage adjustment circuit 5 in each of the above embodiments is possible.

[0101]

As described above, according to the first aspect of the present invention, light enters from one of the polarizing plates of the light modulation element, and the light passing through the polarizing plate is converted into linearly polarized light. When the linearly polarized light passes through a plurality of liquid crystal panels, the linearly polarized light sequentially turns at an angle depending on the wavelength and the degree of birefringence due to the birefringence of each liquid crystal panel. The birefringence of the liquid crystal panel has wavelength dependence, and the angle at which the linearly polarized light that has passed through the polarizing plate turns every time it passes through the liquid crystal panel is different for each wavelength.

On the other hand, another polarizing plate is arranged on the emission side of the liquid crystal panel in the final stage. When the retardation of the liquid crystal of each liquid crystal panel is changed by the retardation changing means, the polarization direction of the linearly polarized light component or the long axis direction of the elliptically polarized light component of the light emitted from the liquid crystal panel at the last stage is correspondingly changed. The wavelength of light that becomes parallel to the polarization axis of the other polarizing plate can be appropriately selected. Thus, light of any color can be transmitted by the light modulation element.

According to the second aspect of the present invention, such a light modulation element is combined with a transmission type or reflection type display means, and the light modulation element selectively transmits light of a plurality of wavelengths. Images corresponding to the plurality of colors are displayed by the display means during the period of the afterimage effect of the human being. Thereby, a color display device can be configured. In the color imaging device, which is the prior art of the photodetection device of the present invention, an area-divided micro color filter is used on the light incident side of the solid-state imaging device. Thus, the necessity of using a micro color filter is eliminated, and the resolution is substantially improved three times or more, and the image quality is improved. Further, as compared with the prior art in which a micro color filter is mounted, the present invention simplifies the manufacturing labor and configuration, and improves the yield. In the color sensor which is a prior art of the photodetector of the present invention, three color filters of red, green and blue are provided on the sensor body, and the back electrode and the transparent electrode are separated for each color filter. In comparison with such a conventional color sensor, the photodetector of the present invention can achieve a simpler configuration and a smaller size. The color copier according to the fourth aspect eliminates the need for using a mechanical structure for switching the color of light from a light source applied to a document in the prior art. Therefore, in the color copying machine of the present invention, it is possible to simplify the configuration and to improve the durability.
According to the color printing plate making apparatus of claim 5, the necessity of using the red, green and blue filters and the plurality of photoelectric tubes corresponding thereto in the prior art is eliminated. Miniaturization and simplification can be achieved. According to the image input / output device of the sixth aspect, in the color facsimile device of the prior art, compared with a configuration in which three color, for example, micro color filters are provided on the line image sensor, the present invention has a smaller configuration. And simplification can be achieved. In still another prior art, the color filters of three colors are moved in parallel, for example, mechanically to reduce reflected light from a color original by three.
According to the present invention, the configuration can be simplified and the size can be reduced as compared with the configuration in which the color is separated. According to the image processing apparatus of the present invention, an arbitrary wavelength required for the calculation can be easily generated and selected, and a plurality of images are superimposed and a part thereof is deleted from one image. Image processing and the like can be achieved with a simple configuration and downsized. Further, according to the illuminating device of the present invention, it is possible to extract the light of any one of the wavelengths including the wavelengths of the plurality of colors from the light source and irradiate the illuminated object with the light. It is possible to realize a lighting device which is excellent in durability and has a reduced time for selecting light to be irradiated.

[Brief description of the drawings]

FIG. 1 is a system diagram of a light modulation device 1 according to one embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a liquid crystal panel Pi.

FIG. 3 is a diagram showing an optical configuration of a light modulation element 1.

FIG. 4 is a diagram illustrating the behavior of linearly polarized light in the liquid crystal panel P1.

FIG. 5 is a graph illustrating the wavelength dependence of the refractive index anisotropy Δn.

FIG. 6 is a graph illustrating the wavelength dependence of transmitted light intensity.

FIG. 7 is a graph illustrating voltage dependency of refractive index anisotropy Δn.

FIG. 8 is a graph illustrating an operation of the light modulation element 1.

FIG. 9 is a graph showing a relationship between a response time τ and a cell thickness d in the light modulation element 1.

FIG. 10 is a block diagram illustrating a configuration example of a light modulation element 1a according to another embodiment.

FIG. 11 is an exploded perspective view of a liquid crystal display device 26 according to another embodiment of the present invention.

FIG. 12 is a block diagram of the liquid crystal display device 26.

FIG. 13 is a system diagram of the projection display device 35.

FIG. 14 is a block diagram of a color imaging device 41.

FIG. 15 is a block diagram of a color sensor 47.

FIG. 16 is a system diagram of the color copying machine 57.

FIG. 17 is a system diagram of the color printing plate-making apparatus 63.

FIG. 18 is a block diagram of a color facsimile apparatus 79.

FIG. 19 is a system diagram of a reading element 81a.

FIG. 20 is a system diagram of a reading element 81b.

21 is a system diagram of the image calculation device 90. FIG.

FIG. 22 is a diagram illustrating the operation of the image calculation devices 90a to 90c.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Light modulation element 2, 3 Polarizer 12 Liquid crystal 23 High frequency power supply 24 Low frequency power supply 25 Switching circuit 26 Liquid crystal display device 29 Liquid crystal color filter 35 Projection display device 41 Color imaging device 47 Color sensor 57 Color copier 63 Color printing Plate making device 79 Color facsimile device 81, 81a, 81b Reading element 90, 90a, 90b, 90c Image operation device

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-167527 (JP, A) JP-A-2-22 (JP, A) JP-A-50-110296 (JP, A) JP-A-2- 153315 (JP, A) Japanese Utility Model 4-13924 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02F 1/1347 G02F 1/1335

Claims (8)

(57) [Claims] 1. A light modulator comprising a plurality of liquid crystal panels having a liquid crystal sealed between a pair of transparent electrodes between a pair of polarizing plates, wherein each liquid crystal panel transmits only light having a wavelength of λ0. So that
With respect to the refractive index anisotropy Δn of the liquid crystal, the layer thickness d of the liquid crystal, and the integer m, retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2, m ≧ 1. And a retardation changing means for changing the retardation Δnd of the liquid crystal panel adjacent to the polarizing plate on the incident side of the liquid crystal panel adjacent to the polarizing plate. The angle between the liquid crystal molecules on the incident side of each matching liquid crystal panel is 2α, and the exit side is parallel to the polarization direction of the linearly polarized light component of the output light of the final stage liquid crystal panel or the major axis direction of the elliptically polarized light component. Wherein the polarization axis of the polarizing plate is selected. 2. A display device, wherein light from one light source including wavelengths of a plurality of colors is radiated to a transmission type or reflection type display means and a light modulation element to perform display, and within a period of an afterimage effect, the plurality of light sources are displayed. The image corresponding to each color is displayed by the display means, and for each display period of the image for each color,
The light modulating element switches the color of light transmitted therethrough, and the light modulating element is a light modulating element comprising a plurality of liquid crystal panels interposing liquid crystal between a pair of transparent electrodes between a pair of polarizing plates, Each liquid crystal panel transmits only light of wavelength λ0,
With respect to the refractive index anisotropy Δn of the liquid crystal, the layer thickness d of the liquid crystal, and the integer m, retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2, m ≧ 1. And a retardation changing means for changing the retardation Δnd of the liquid crystal panel adjacent to the polarizing plate on the incident side of the liquid crystal panel adjacent to the polarizing plate. The angle between the liquid crystal molecules on the incident side of each matching liquid crystal panel is 2α, and the exit side is parallel to the polarization direction of the linearly polarized light component of the output light of the final stage liquid crystal panel or the major axis direction of the elliptically polarized light component. Wherein the polarization axis of the polarizing plate is selected. 3. A light modulating element is arranged on an incident side of a light detecting means for outputting a detection signal corresponding to the intensity of incident light, wherein the light modulating element comprises a liquid crystal between a pair of polarizing plates and a pair of transparent electrodes. A light modulation element including a plurality of sealed liquid crystal panels, wherein each liquid crystal panel transmits only light of wavelength λ0.
With respect to the refractive index anisotropy Δn of the liquid crystal, the layer thickness d of the liquid crystal, and the integer m, retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2, m ≧ 1. And a retardation changing means for changing the retardation Δnd of the liquid crystal panel adjacent to the polarizing plate on the incident side of the liquid crystal panel adjacent to the polarizing plate. The angle between the liquid crystal molecules on the incident side of each matching liquid crystal panel is 2α, and the exit side is parallel to the polarization direction of the linearly polarized light component of the output light of the final stage liquid crystal panel or the major axis direction of the elliptically polarized light component. Wherein the polarization axis of the polarizing plate is selected. 4. An apparatus according to claim 1, wherein one of a light source for generating light including wavelengths of a plurality of colors, an original, and photoelectric conversion means for forming an optical image of the original and converting the optical image into an electric signal. And a color image forming means for forming a color image on a recording medium using the developer for each of the plurality of colors based on an electric signal obtained by the photoelectric conversion means. The element is a light modulation element including a plurality of liquid crystal panels in which liquid crystal is sealed between a pair of polarizers and a pair of transparent electrodes. Each liquid crystal panel transmits only light of wavelength λ0. ,
With respect to the refractive index anisotropy Δn of the liquid crystal, the layer thickness d of the liquid crystal, and the integer m, retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2, m ≧ 1. And a retardation changing means for changing the retardation Δnd of the liquid crystal panel adjacent to the polarizing plate on the incident side of the liquid crystal panel adjacent to the polarizing plate. The angle between the liquid crystal molecules on the incident side of each matching liquid crystal panel is 2α, and the exit side is parallel to the polarization direction of the linearly polarized light component of the output light of the final stage liquid crystal panel or the major axis direction of the elliptically polarized light component. A color copier characterized in that the polarizing axis of the polarizing plate is selected. 5. One of a light source for generating light including a plurality of colors of wavelengths, a document, and an optical image of the document, and a photoelectric conversion unit for converting the optical image into an electric signal. Plate material processing means for arranging two light modulating elements and forming a document image for each color on a plurality of color plate materials to be a printing plate based on an electric signal obtained from the photoelectric conversion means; The element is a light modulation element including a plurality of liquid crystal panels in which liquid crystal is sealed between a pair of polarizers and a pair of transparent electrodes. Each liquid crystal panel transmits only light of wavelength λ0. ,
With respect to the refractive index anisotropy Δn of the liquid crystal, the layer thickness d of the liquid crystal, and the integer m, retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2, m ≧ 1. And a retardation changing means for changing the retardation Δnd of the liquid crystal panel adjacent to the polarizing plate on the incident side of the liquid crystal panel adjacent to the polarizing plate. The angle between the liquid crystal molecules on the incident side of each matching liquid crystal panel is 2α, and the exit side is parallel to the polarization direction of the linearly polarized light component of the output light of the final stage liquid crystal panel or the major axis direction of the elliptically polarized light component. A printing plate-making apparatus, wherein the polarizing axis of the polarizing plate is selected. 6. An image pickup unit picks up an image of a target object for each of a plurality of colors via a light modulation element, stores image data from the image pickup unit for each color in an image memory, and inputs a color image, or Based on the image data for each of a plurality of colors stored in the image memory, an image is displayed on the display means, and a color image is output by switching the color of the transmitted light by the light modulation element. Is a light modulation element including a plurality of liquid crystal panels having a liquid crystal sealed between a pair of transparent electrodes between a pair of polarizers. Each liquid crystal panel transmits only light of wavelength λ0.
With respect to the refractive index anisotropy Δn of the liquid crystal, the layer thickness d of the liquid crystal, and the integer m, retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2, m ≧ 1. And a retardation changing means for changing the retardation Δnd of the liquid crystal panel adjacent to the polarizing plate on the incident side of the liquid crystal panel adjacent to the polarizing plate. The angle between the liquid crystal molecules on the incident side of each matching liquid crystal panel is 2α, and the exit side is parallel to the polarization direction of the linearly polarized light component of the output light of the final stage liquid crystal panel or the major axis direction of the elliptically polarized light component. An image input / output device, wherein the polarization axis of the polarizing plate is selected. 7. A light source for generating light of a plurality of wavelengths, a light modulator for transmitting only a specific wavelength component of light from the light source, and transmitting or reflecting light of one specific wavelength component corresponding to a display image. And a plurality of transmissive or reflective display elements that transmit or reflect the light of the remaining wavelength components.The light modulation element includes a plurality of liquid crystal cells between a pair of polarizers and a liquid crystal sealed between a pair of transparent electrodes. A light modulation element having a liquid crystal panel interposed therebetween, wherein each liquid crystal panel transmits only light having a wavelength of λ0.
With respect to the refractive index anisotropy Δn of the liquid crystal, the layer thickness d of the liquid crystal, and the integer m, retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2, m ≧ 1. And a retardation changing means for changing the retardation Δnd of the liquid crystal panel adjacent to the polarizing plate on the incident side of the liquid crystal panel adjacent to the polarizing plate. The angle between the liquid crystal molecules on the incident side of each matching liquid crystal panel is 2α, and the exit side is parallel to the polarization direction of the linearly polarized light component of the output light of the final stage liquid crystal panel or the major axis direction of the elliptically polarized light component. An image processing device, wherein the polarizing axis of the polarizing plate is selected. 8. A light from a light source that generates light including wavelengths of a plurality of colors is irradiated as one of the lights of the plurality of colors via a light modulation element, and the light modulation element includes a pair of polarizing plates. A light modulation element including a plurality of liquid crystal panels in which liquid crystal is sealed between a pair of transparent electrodes, wherein each liquid crystal panel transmits only light of wavelength λ0.
With respect to the refractive index anisotropy Δn of the liquid crystal, the layer thickness d of the liquid crystal, and the integer m, retardation Δnd is selected so as to satisfy Δnd / λ0 = (2m−1) / 2, m ≧ 1. And a retardation changing means for changing the retardation Δnd of the liquid crystal panel adjacent to the polarizing plate on the incident side of the liquid crystal panel adjacent to the polarizing plate. The angle between the liquid crystal molecules on the incident side of each matching liquid crystal panel is 2α, and the exit side is parallel to the polarization direction of the linearly polarized light component of the output light of the final stage liquid crystal panel or the major axis direction of the elliptically polarized light component. The polarizing axis of the polarizing plate is selected.