CN1523436A - Method for manufacturing color filter and semi-transmission type liquid crystal display device - Google Patents

Abstract

The present invention provides a method for manufacturing a color filter and a semi-transmissive liquid crystal display device. The color filter has different thicknesses, and the semi-transmissive liquid crystal display device has the filter. The liquid crystal display device includes a lower substrate having an insulating layer thereon; a lower electrode located on the insulating layer, and the lower electrode has a reflective area and a transmissive area; an upper substrate having a color filter on a surface corresponding to the lower substrate, wherein the color filter has different thickness areas; a flat layer located on the color filter; an upper electrode located on the flat layer; and a liquid crystal layer disposed between the upper substrate and the lower substrate.

Description

Manufacturing method of color filter and semi-transmissive liquid crystal display device

technical field

The invention relates to a transflective liquid crystal display and its preparation method, and in particular to a semi-transmissive liquid crystal display with color filters of different thicknesses and its preparation method.

Background technique

Reflective liquid crystal display (RLCD) can be divided into two categories: "total reflection" and "semi-transmission". The fully reflective LCD does not use a backlight, and uses a reflector attached to the LCD panel to reflect external light. Use the front light as the fill light. The transflective LCD (transflective LCD) uses an external light source when the external light is sufficient, and lights up the backlight when the external light is insufficient. It is a method that saves power and has auxiliary light. ) and the preferred choice of portable liquid crystal display devices such as laptop computers.

Please refer to FIG. 1 . FIG. 1 is a schematic diagram showing an example of a conventional transflective LCD structure.

The structure of the existing transflective LCD includes:

A base 100 with an insulating layer 110 thereon;

The lower electrode 120 is located on the insulating layer 110. The lower electrode 120 has a reflective region 122 and a transmissive region 124, wherein the reflective region 122 is, for example, an aluminum layer, and the transmissive region 124 is, for example, indium tin oxide (ITO). layer;

An upper substrate 160 has a color filter 150 on its inner surface;

An upper electrode 140 is located on the color filter 150; and

A liquid crystal layer 130 is disposed between the upper substrate 160 and the lower substrate 100 .

However, when the above-mentioned conventional transflective LCD is in the reflective mode, the ambient light (reflected light) 170 passes through the color filter 150 twice. While in the transmissive mode, the number of times the backlight (transmissive light) 180 passes through the color filter 150 is one time. Therefore, the display colors in the reflective mode and the transmissive mode cannot be the same, that is, there is a problem that the color density (color saturation, color purity) differs greatly, which reduces the display-quality of the transflective LCD.

Recently, the industry proposes a transflective LCD with color filters of different thicknesses. The manufacturing process of the color filter of the transflective LCD will be described below with reference to FIGS. 2A to 2C .

First, please refer to FIG. 2A , a patterned transparent photoresist layer 210 is firstly formed on a substrate 200 , and the transparent photoresist layer 210 corresponds to the reflective region 201 of the transflective LCD.

Next, please refer to FIG. 2B , a patterned red photoresist layer 220 is formed on part of the substrate 200 and part of the transparent photoresist layer 210 .

Next, referring to FIG. 2C , a green photoresist layer 230 and a blue photoresist layer 240 are sequentially patterned on part of the substrate 200 and part of the transparent photoresist layer 210 . In this way, the existing color filters 250 with different thicknesses are completed.

However, since the transparent photoresist layer 210 must be formed on the substrate 200 in the prior art, it is necessary to add a photomask, which increases the cost. Moreover, the surfaces of the red photoresist layer 220, the green photoresist layer 230 and the blue photoresist layer 240 coated on the transparent photoresist layer 210 are not flat, that is, It is not easy to control the film thickness of the red photoresist layer 220, the green photoresist layer 230 and the blue photoresist layer 240 in the existing technology, so it is not easy to completely solve the color density (color saturation, color purity) difference problem.

Contents of the invention

In view of this, an object of the present invention is to provide a transflective LCD, which is characterized in that it has color filters with different thicknesses.

Another object of the present invention is to provide a color filter with different thicknesses, which is mainly used in transflective LCD.

Yet another object of the present invention is to provide a method for preparing color filters with different thicknesses.

In order to achieve the above object, the present invention provides a semi-transmissive liquid crystal display device with color filters of different thicknesses, wherein the first substrate and the second substrate are arranged oppositely, and the color filter is located on the first substrate and corresponds to the transmissive The color filter in the region has a first thickness, the color filter corresponding to the reflective region has a second thickness, and the first thickness is greater than the second thickness. In addition, the liquid crystal layer is interposed between the second substrate and the color filter.

In the above transflective liquid crystal display device with color filters of different thicknesses, the first substrate is the lower substrate and includes a thin film transistor array, and the second substrate is the upper substrate. Alternatively, the second substrate is a lower substrate and includes a thin film transistor array, and the first substrate is an upper substrate.

Among them, the manufacturing method of color filters with different thicknesses includes the following steps: (a) providing a substrate, the substrate has a first region and a second region; (b) forming a thick color photoresist layer on the substrate; and (c) removing part of the thick color photoresist layer in the second region by a photolithography process to form a thin color photoresist layer in the first region on this substrate in Zone 2.

Wherein, the first region corresponds to a transmissive region of a transflective LCD, and the second region corresponds to a reflective region of a transflective LCD.

Also, the method of removing part of the thick colored photoresist layer in the second region in step (c) is achieved by exposing and developing with a photomask. Wherein, when the thick color photoresist layer is composed of a positive photoresist, the photomask used includes a complete light-shielding pattern corresponding to the first region and a partially light-transmitting pattern corresponding to the second region . When the thick color photoresist layer is composed of a negative photoresist, the photomask used includes a fully transparent pattern corresponding to the first region and a partially transparent pattern corresponding to the second region .

In order to make the above-mentioned objects, features and advantages of the present invention more comprehensible, preferred embodiments will be described in detail below together with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic diagram showing an example of a conventional transflective LCD structure;

2A-2C are process sectional views showing existing color filters with different thicknesses;

3A to 3C are process sectional views showing color filters with different thicknesses of the present invention;

Figure 4 is a schematic top view of the photomask used in the present invention when the colored photoresist is a positive photoresist;

Figure 5 is a schematic top view of a photomask used in the present invention when the colored photoresist is a negative photoresist;

Fig. 6 is a structural schematic diagram showing color filters with different thicknesses of the present invention applied to a semi-transmissive LCD device; and

FIG. 7 is a schematic diagram showing the structure of color filters with different thicknesses of the present invention applied to another type of transflective LCD device.

Explanation of reference signs

Existing parts (Fig. 1, Fig. 2A～2C)

100～lower substrate; 110～insulating layer; 120～bottom electrode; 122～reflecting area; 124～transmitting area; 130～liquid crystal layer; 140～upper electrode; 150～color filter; 160～upper substrate; 170～outside Light (i.e. reflected light); 180～backlight (i.e. transmitted light); 200～substrate; 201～reflective area; 210～transparent photoresist layer; 220～red photoresist layer; 230～green photoresist layer Resist layer; 240 ~ blue photoresist layer; 250 ~ existing color filters with different thicknesses.

Part of the present invention (Fig. 3A-3C, Fig. 4, Fig. 5, Fig. 6, Fig. 7)

300～substrate; 301～transmissive region; 302～reflective region; 310～thick colored photoresist layer; 320～thin colored photoresist layer; 330～transparent planar layer; 410, 510～photomask ; 420, 520 ~ first pattern; 430, 530 ~ second pattern; 1050, 1070 ~ gap (slit); 1060, 1080 ~ micro pattern; 600, 700 ~ lower substrate; 610, 710 ~ insulating layer; 620, 720 ~ lower electrode; 622, 722 ~ reflective area; 624, 724 ~ transmissive area; 630, 755 ~ liquid crystal layer; 640, 750 ~ upper electrode; 645, 740 ~ flat layer; 650, 730 ~ color filter; 651, 731～thick area; 652, 732～thin area; 660, 760～upper substrate; 670, 770～ambient light (i.e. reflected light); 680, 780～backlight (i.e. transmitted light); 690, 790～semi-transmissive LCD device.

Detailed ways

Please refer to Figures 3A to 3C, which are used to illustrate the process of color filters with different thicknesses in the transflective LCD of the present invention. Among them, other elements used in the liquid crystal display disclosed in the present invention are the same as the existing ones, and are not Let me repeat this again. It should be noted here that, in order to show the features of the present invention simply and clearly, FIGS. 3A-3C are cross-sectional diagrams showing the process of color filters corresponding to any pixel. Also, a black matrix (black matrix) pattern may be formed between each pixel, but its illustration is omitted here.

First, please refer to FIG. 3A , a substrate 300 is provided, and the substrate 300 has a first region 301 and a second region 302 . Wherein, the substrate 300 is, for example, a glass substrate. Also, the first region 301 corresponds to a transmissive region of the transflective LCD device, and the second region 302 corresponds to a reflective region of the transflective LCD device.

Next, still referring to FIG. 3A , a thick color photoresist (color resist) layer 310 is coated on the substrate 300 . The color of the thick colored photoresist layer 310 is, for example, red, green or blue.

Next, referring to FIG. 3B , the thick colored photoresist layer 310 located in the second region 302 is partially removed, and a thin colored photoresist layer 320 is formed on the substrate 300 located in the second region 302 superior. Here, two examples are given to illustrate the method of forming FIG. 3B , but this does not limit the present invention.

Case 1

When the thick color photoresist layer 310 is composed of positive photoresist (positive photoresist), the method for removing part of the thick color photoresist layer 310 located in the second region 302 is as follows steps described above.

Referring to FIG. 4, a photolithography procedure (photolithography procedure) using an exposure light (not shown) and a photomask (reticle or photomask) 410 is performed to perform a thick color photoresist layer 310. Part of the thick colored photoresist layer 310 located in the second region 302 is removed by photolithography, so as to form a thin colored photoresist layer 320 on the substrate 300 in the second region 302 . Wherein, the photomask 410 includes: a first pattern 420 corresponding to the first area 301 (ie, a complete light-shielding pattern), and a second pattern 430 (ie, a partially light-transmitting pattern) corresponding to the second area 302 . The first pattern 420 is used to shield the first region 301 to prevent the exposure source from irradiating the thick color photoresist layer 310 of the first region 301 . The second pattern 430 is used to reduce the exposure intensity penetrating through the second region 302 , that is, the second pattern 430 of the photomask 410 can reduce the exposure resolution, and the resolution can be reduced to about 1/2 at least.

Since the second pattern 430 needs to have the effect of reducing the exposure intensity, it can be achieved by using a half-tone pattern. As an example, the second pattern 430 can be composed of a plurality of micropatterns 1060 separated by appropriate gaps (slit) 1050. The micropatterns 1060 can be light-transmitting patterns or opaque patterns, but when the micropatterns 1060 are transparent When light patterns are used, the gaps 1050 used to separate the micropatterns 1060 in the figure must be opaque. Conversely, when the micropattern 1060 is a non-transmissive pattern, the gap 1050 must be transparent, as shown in FIG. 4 . By controlling the size of the above-mentioned micropattern 1060 and/or the gap 1050, the light is partially blocked and cannot be completely transmitted, so that the intensity of light transmission can be reduced during the photolithography step so that the thick color photoresist layer 310 cannot It will be completely developed, that is, a certain thickness of the color photoresist layer (ie, the thin color photoresist layer 320 ) remains after the development. The shape design of the micropattern 1060 is not particularly limited, and may be in any shape, such as rectangle, circle, square, rectangle, rhombus, or triangle, etc., or the micropattern 1060 is in the shape of a strip as a whole. In addition, the film thickness of the thin colored photoresist layer 320 can be adjusted by controlling the size of the micropattern 1060 and/or the gap 1050 .

Case 2

When the thick color photoresist layer 310 is made up of negative photoresist (negative photoresist), the method for removing part of the thick color photoresist layer 310 located in the second region 302 is as follows steps described above.

Referring to FIG. 5 , a photolithography process using an exposure source (not shown) and a photomask 510 is performed, and the thick color photoresist layer 310 is photoetched and the removed part is located in the second region 302 thick color photoresist layer 310 , thus forming a thin color photoresist layer 320 on the substrate 300 located in the second region 302 . Wherein, the photomask 510 includes: a first pattern 520 (ie, light-transmitting pattern) corresponding to the first region 301 , and a second pattern 530 (ie, partially light-transmitting pattern) corresponding to the second region 302 . The first pattern 520 is used to fully expose the thick color photoresist layer 310 of the first region 301 . The second pattern 530 is used to reduce the exposure intensity penetrating through the second region 302 , that is, the second pattern 530 of the photomask 510 can reduce the exposure resolution, and the resolution can be reduced to about 1/2 at least.

Since the second pattern 530 needs to have the effect of reducing the exposure intensity, it can be achieved by using a half-tone pattern. As an example, the second pattern 530 can be composed of a plurality of micropatterns 1080 separated by appropriate gaps (slit) 1070. The micropatterns 1080 can be light-transmitting patterns or opaque patterns, but when the micropatterns 1080 are transparent When light patterns are used, the gaps 1070 used to separate the micropatterns 1080 in the figure must be opaque, as shown in FIG. 5 . On the contrary, when the micropattern 1080 is a non-transmissive pattern, the gap 1070 must be transparent. By controlling the size of the above-mentioned micropattern 1080 and/or the gap 1070, so that the light is partially blocked and cannot be completely transmitted, the light transmission intensity can be reduced during the photolithography step, so that the thick color photoresist layer 310 cannot It will be completely developed, that is, a certain thickness of the color photoresist layer (ie, the thin color photoresist layer 320 ) remains after the development. The shape design of the micropattern 1080 is not particularly limited, and may be in any shape, such as rectangle, circle, square, rectangle, rhombus, or triangle, etc., or the micropattern 1080 is in the shape of a strip as a whole. In addition, the film thickness of the thin colored photoresist layer 320 can be adjusted by controlling the size of the micropattern 1080 and/or the gap 1070 .

In addition, it should be explained here that, the positive photoresist or the negative photoresist used in the thick colored photoresist layer 310 are photosensitive resins or polymer materials. Positive photoresist is a photoresist itself that is insoluble in developer, but after exposure, it will dissociate into a structure that is soluble in developer; negative photoresist is photoresist Links are created after exposure, making the exposed photoresist structure insoluble in the developer. As long as it is a generally commercially available color "positive photoresist" or "negative photoresist", it is suitable for the process of the present invention and can achieve the effect of the present invention.

Afterwards, referring to FIG. 3C , in order to facilitate subsequent processes in the future, a layer with high transmittance (or high transparency) can be formed on the thick colored photoresist layer 310 and the thin colored photoresist layer 320. ) flat layer (transparent planarization layer, or overcoat) 330. Wherein, the planar layer 330 is composed of organic insulating materials or inorganic insulating materials, organic insulating materials such as benzocyclobutene (BCB), acryl resin (acryl resin), etc., and inorganic insulating materials such as SiO ₂ , SiN _x and so on. In this way, the color filters with different thicknesses of the present invention are completed.

It should be reminded here that the present invention only uses one photolithography step and one photomask (410/510) to form color filters with different thicknesses, so the manufacturing cost can be reduced. Furthermore, since the color filter of the present invention is formed on a flat substrate 300, the thickness of the color filter can be easily controlled.

Next, please refer to FIG. 6 , which is a schematic diagram illustrating the structure of color filters with different thicknesses applied to a semi-transmissive LCD device according to the present invention. In order not to confuse the features of the present invention, the process of the transflective LCD device will not be described in detail here.

A transflective LCD device 690 with color filters of different thicknesses, comprising the following components:

The lower substrate 600 has an insulating layer 610 thereon, and the lower substrate 600 may include a thin film transistor array (not shown).

A lower electrode (or reflective electrode, reflective electrode) 620 is located on the insulating layer 610. The lower electrode 620 has a reflective region 622 and a transmissive region 624, wherein the reflective region 622 is, for example, an aluminum layer, and the transmissive region 624 is, for example, Indium tin oxide (ITO) layer or indium zinc oxide (IZO) layer.

An upper substrate 660, which has a color filter 650 on a surface corresponding to the lower substrate 600, wherein the color filter 650 has a first thickness region 651 and a second thickness region 652, wherein, in the present invention In a preferred embodiment, the first thickness region 651 is a thicker region and corresponds to the transmissive region 624 , and the second thickness region 652 is a thinner region and corresponds to the reflective region 622 .

A flat layer (or called cover layer, overcoat) 645 is located on the color filter 650 and corresponds to the upper substrate 660. The flat layer 645 is formed of a material with high transmittance, such as SiO ₂ , SiN _x and so on.

An upper electrode (or common electrode, common electrode) 640 is located on the transparent flat layer 645 and corresponds to the color filter 650. The upper electrode 640 is, for example, an ITO or IZO layer.

A liquid crystal layer 630 is sandwiched between the upper substrate 660 and the lower substrate 600 .

Therefore, when the transflective LCD device 690 is in the reflective mode, the number of times the ambient light (reflected light) 670 passes through the second thickness region 652 of the color filter 650 is twice. While in the transmissive mode, the number of times the backlight (transmissive light) 680 passes through the first thickness region 651 of the color filter 650 is one time. Since the first thickness region 651 is thicker than the thickness of the second thickness region 652, the display colors in the reflective mode and the transmissive mode are similar, that is to say, the existing color density (color saturation, color purity) is very different. , which can improve the display-quality.

Please refer to FIG. 7 again, which is a schematic diagram illustrating the application of color filters with different thicknesses in the present invention to another type of transflective LCD device. The transflective LCD device shown in FIG. 7 adopts COA (color filter on array) technology, which can improve the alignment of the upper and lower substrates. In order not to confuse the features of the present invention, the process of the transflective LCD device will not be described in detail here.

A transflective LCD device 790 with color filters of different thicknesses, comprising the following components:

The lower substrate 700 has an insulating layer 710 thereon, and the lower substrate 700 may include a thin film transistor array (not shown).

A lower electrode (or reflective electrode, reflective electrode) 720 is located on the insulating layer 710. The lower electrode 720 has a reflective region 722 and a transmissive region 724, wherein the reflective region 722 is, for example, an aluminum layer, and the transmissive region 724 is, for example, Indium tin oxide (ITO) layer or indium zinc oxide (IZO) layer.

A color filter 730 with different thicknesses manufactured by the method of the present invention is formed on the bottom electrode 720 . Wherein the color filter 730 has a first thickness region 731 and a second thickness region 732, wherein the first thickness region 731 is a thicker region and corresponds to the transmission region 724, and the second thickness region 732 is a thicker region. The thin area corresponds to the reflection area 722 .

A flat layer (or overcoat) 740 is located on the color filter 730. The flat layer 740 is formed of a material with high transmittance, such as SiO2, SiNx and so on.

An upper base 760 corresponding to the lower base 700 .

An upper electrode (or common electrode, common electrode) 750 is located on the upper substrate 760, and the upper electrode 750 is, for example, an ITO or IZO layer.

A liquid crystal layer 755 is sandwiched between the upper substrate 760 and the lower substrate 700 .

Therefore, when the transflective LCD device 790 is in the reflective mode, the number of times the ambient light (ie reflected light) 770 passes through the second thickness region 732 of the color filter 730 is twice. While in the transmission mode, the number of times the backlight (ie transmitted light) 780 passes through the first thickness region 731 of the color filter 730 is one time. Since the thickness of the first thickness region 731 is thicker than that of the second thickness region 732, the display colors in the reflective mode and the transmissive mode are similar, which solves the problem that the existing color density (color saturation) is very different, and can Improve display quality.

The above is just an example of using a photomask with a halftone pattern to form a color filter of a semi-transmissive LCD device with different thicknesses, but the color filters with different thicknesses can also use a color filter with different transmittance For example, a photomask has a transmissive region and a semi-transmissive region at the same time, so that the exposure degree of the photoresist is different, so that the photoresist forms different regions.

Features and advantages of the present invention

The present invention is characterized in that: using different resolutions or transmittances on the photomask, part of the color filter corresponding to the reflection area is removed to form a color filter with different thicknesses, and the color filter The light sheet is applied to a transflective LCD device.

In this way, through the present invention, color filters with different thicknesses can be formed with one photomask, which can not only improve the display quality of the transflective LCD device, but also reduce the cost. Furthermore, compared with the existing method, since the color filter of the present invention is formed on a flat substrate, it is easier to control the film thickness of each region in the color filter, thereby solving the problem of existing color density. (Color saturation, color purity) difference problem.

Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the scope of the present invention. Those skilled in the art should be able to make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the invention should be determined by the appended claims.

Claims (15)

1. A semi-transmissive liquid crystal display device with color filters of different thicknesses has a transmissive area and a reflective area, and the semi-transmissive liquid crystal display device comprises: A first base and a pair of facing second bases; A color filter located on the first substrate, wherein the color filter corresponding to the transmission area has a first thickness, the color filter corresponding to the reflection area has a second thickness, and the first thickness greater than the second thickness; and A liquid crystal layer is sandwiched between the second substrate and the color filter. 2. The transflective liquid crystal display device with color filters of different thicknesses as claimed in claim 1, wherein the first substrate comprises a thin film transistor array. 3. The transflective liquid crystal display device with color filters of different thicknesses as claimed in claim 1, wherein the second substrate comprises a thin film transistor array. 4. The transflective liquid crystal display device with color filters of different thicknesses as claimed in claim 1, further comprising a flat layer disposed between the color filters and the liquid crystal layer. 5. A transflective liquid crystal display device with color filters of different thicknesses, comprising: a substrate having an insulating layer thereon; a lower electrode, formed on the insulating layer, the lower electrode has a reflective area and a transmissive area; an upper base facing the lower base; A color filter disposed on a surface of the upper substrate, wherein the color filter has a first thickness region and a second thickness region, wherein the first thickness region is thicker than the second thickness region, and The first thickness region corresponds to the transmissive region, and the second thickness region corresponds to the reflective region; an upper electrode formed on the color filter and facing the lower substrate; and A liquid crystal layer is sandwiched between the upper substrate and the lower substrate. 6. The transflective liquid crystal display device with color filters of different thicknesses as claimed in claim 5, further comprising a flat layer disposed between the color filters and the liquid crystal layer. 7. A transflective liquid crystal display device with color filters of different thicknesses, comprising: a substrate having an insulating layer thereon; a lower electrode, formed on the insulating layer, the lower electrode has a reflective area and a transmissive area; A color filter formed on the lower electrode, wherein the color filter has a first thickness region and a second thickness region, wherein the first thickness region is thicker than the second thickness region, and the first thickness region A thickness zone corresponds to the transmissive zone, and a second thickness zone corresponds to the reflective zone; an upper base facing the lower base; an upper electrode formed on the upper substrate and facing the lower substrate; and A liquid crystal layer is sandwiched between the upper electrode and the color filter. 8. The transflective liquid crystal display device with color filters of different thicknesses as claimed in claim 7, further comprising a flat layer disposed between the color filters and the liquid crystal layer. 9. A method of manufacturing color filters with different thicknesses, comprising the following steps: (a) is a substrate having a first region and a second region; (b) forming a thick colored photoresist layer on the substrate; and (c) performing a photolithography process using a photomask for photolithography of the thick color photoresist layer to remove part of the thick color photoresist layer located in the second region , thus forming a thin colored photoresist layer on the substrate located in the second region. 10. The method of manufacturing color filters with different thicknesses as claimed in claim 9, wherein the pattern on the photomask corresponding to the second region is a halftone pattern. 11. The method of manufacturing color filters with different thicknesses as claimed in claim 9, wherein the pattern on the photomask corresponding to the second region comprises a plurality of micropatterns. 12. The manufacturing method of color filters with different thicknesses as claimed in claim 9, wherein the first region corresponds to the transmissive region of the semi-transmissive liquid crystal display, and the second region corresponds to the reflective region of the semi-transmissive liquid crystal display . 13. The method for manufacturing color filters with different thicknesses as claimed in claim 9, wherein the thick color photoresist layer is a positive photoresist, and the photomask includes a layer corresponding to the first region. A complete light-shielding pattern and a part of the light-transmitting pattern corresponding to the second area. 14. The method for manufacturing color filters with different thicknesses as claimed in claim 9, wherein the thick color photoresist layer is a negative photoresist, and the photomask includes a layer corresponding to the first region. A completely transparent pattern and a part of the transparent pattern corresponding to the second region. 15. The method for manufacturing color filters with different thicknesses as claimed in claim 9, further comprising forming a planar layer covering the thick colored photoresist layer and the thin colored photoresist layer.

Images