JP2002365418A - Color filter for liquid crystal display element, liquid crystal display device using the same and method for manufacturing the color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color filter exhibiting characteristics similar to a color filter with a pinhole provided on a reflective region at a similar manufacturing cost to, and more easily flattened than, any conventional one. SOLUTION: In the color filter having at least a reflective region and a transmissive region, each of the regions composed of the same material, in a pixel with one color and having a thin film thickness region provided on a part of a coloring layer of the reflective region, if the film thickness of the thin film thickness region is represented by d1 and the film thickness of the normal film thickness region is represented by d0 , the color filter for a semitransmissive liquid crystal display element is characterized by having d1 larger than 0 μm and d0 -d1 smaller than 2 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter used for a liquid crystal display device which may be used for both transmissive display and reflective display.

[0002]

2. Description of the Related Art Many liquid crystal display devices for mobile applications such as PDAs and mobile phones are capable of displaying both transmission and reflection. This type of color liquid crystal display element has a transmissive area and a reflective area, and the color of the transmissive area when performing transmissive display and the color of the reflective area when performing reflective display are displayed. FIG. 3 shows a configuration (cross-sectional view) of a conventional liquid crystal display element. In the transmission area 8, light from the backlight light source 3 passes through the color material 1 and reaches the display surface (6 in FIG. 3), and display is performed. In the reflection area 7,
The natural light 4 passes through the color material 1 once, is reflected by the reflection film 2, and reaches the display surface again through the color material 1 (5 in FIG. 3).
Display is performed.

[0003] When the same color material is used for the transmissive area and the reflective area, the displayed color is greatly different between the transmissive display and the reflective display. As described above, in the case of the transmissive display, light is displayed only once through the color material, whereas in the case of the reflective display, light is displayed twice through the color material. It is. Another reason is that the light source for transmissive display is a backlight light source and the light source for reflective display is natural light.

The method of making the display colors of the transmission area and the reflection area the same is as follows: (1) The transmission area and / or the reflection area are formed by laminating a plurality of color materials, and the transmission area and the reflection area are formed. A method of changing the color material composition of the color region, (2) a method of changing the film thickness of the color material between the transmission region and the reflection region,
(3) A method of providing a minute transparent area, that is, a pinhole in a part of the reflection area as shown in FIG. 4, and the like. In the method (1) using a plurality of color materials, a color material is applied and formed twice or more with one color, which causes a problem in cost. Since the method of changing the film thickness in (2) cannot be performed until the light source in the transmission area and the reflection area is corrected, the method of laminating a plurality of color materials or using another color material is more display-friendly. preferable. Therefore, even in the method of changing the film thickness including the case of simply changing the film thickness, the color material is applied and formed twice or more with one color. In contrast, (3)
In the method of providing the pinhole, the difference between the transmissive display and the reflective display can be reduced by optimizing the shape and size of the pinhole. In addition, since the pinholes can be formed collectively at the time of patterning the colored layer, an inexpensive color filter can be obtained without increasing the number of coating and forming steps. However, if a pinhole is provided,
If the unevenness difference of the colored layer is large, the flatness of the color filter is deteriorated, and there is a possibility that display defects are likely to occur when the liquid crystal panel is used. Although the flatness can be improved to some extent by applying the overcoat, if the size of the pinhole is small, the overcoat becomes difficult to flow into the pinhole, so that sufficient flattening may not be performed. In addition, when the thickness difference between the pinhole portion and the periphery is large, it is necessary to increase the overcoat film thickness. However, if the thickness of the overcoat is too large, there is a concern that the film hardness of the entire color filter is reduced, so that when the liquid crystal display element is formed, the film thickness tends to be uneven, or the overcoat is easily cracked by thermal stress. However, an excessive increase in film thickness is not preferable.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color filter which exhibits the same characteristics at the same manufacturing cost as a color filter having a pinhole in a reflection area, and which can be flattened more easily than before. It is in.

[0006]

The above objects can be achieved by the following color filters. (1) At least one color pixel has a reflective region and a transmissive region, the reflective region and the transmissive region are formed of the same material, and a low-thickness region is provided in a part of the colored layer of the reflective region. In the color filter, when the film thickness d ₁ in the low film thickness region and the film thickness d _{0 in} the normal film thickness region, d ₁ is larger than ₀ μm and d ₀ −d ₁ is smaller than 2 μm. Color filter for transmissive liquid crystal display devices. (2) TeimakuAtsu area of A ₁ of the area, when the area of the normal thickness region represented as A _0, the volume of the transparent regions caused by low membrane thickening in the red pixel (d ₀ -d ₁₎ × A ₁ The color filter according to (1), wherein the ratio of the color filter to the total volume d ₀ × (A ₁ + A ₀ ) of the reflection area is 2% or more and 25% or less. (3) TeimakuAtsu the area of the region A _1, when the area of the normal thickness region represented as A _0, the volume of the transparent regions caused by low membrane thickening in the green pixel _{(d 0 -d 1) × A} 1 Accounts for 10% or more and 50% of the total volume d ₀ × (A ₁ + A ₀ ) of the reflection area.
(1) The color filter as described in (1) above. (4) TeimakuAtsu area of A ₁ of the area, when the area of the normal thickness region represented as A _0, the volume of the transparent regions caused by low membrane thickening in the blue pixel (d ₀ -d ₁₎ × A ₁ Occupies not more than 20% of the entire reflection area in the volume d ₀ × (A ₁ + A ₀ ) of the color filter according to (1). (5) TeimakuAtsu region is present one or more in one pixel, one of the area of each of the low-thickness region is equal to or is 20 [mu] m ² or more 2000 .mu.m ² (1) to (4) The color filter according to 1. (6) The method according to any one of (1) to (5), wherein two or more low-thickness regions exist in one pixel, and a distance between adjacent low-thickness regions is 10 μm or more. Color filter. (7) The ratio of the volume (d ₀ −d ₁ ) × A ₁ of the transparent region to the volume d ₀ × (A ₁ + A ₀ ) of the entire reflection region is the largest in the green pixel (2). The color filter according to any one of (1) to (6). (8) The color filter for a liquid crystal display device according to any one of (1) to (7), wherein an overcoat layer is formed on the coloring layer. (9) A transflective liquid crystal display device using the color filter according to any one of (1) to (8). (10) The pixel has a reflection area and a transmission area, and for at least one color, the reflection area and the transmission area are colored by the same material, and a part of the coloring layer of the reflection area is reduced in thickness. A method for producing a color filter, characterized in that a transparent region is partially formed in a reflective region. (11) The color according to (10), wherein in the patterning of the colored layer by photolithography, half etching is performed by forming a part of a photomask into a mesh or slit to form the low-thickness region. Manufacturing method of filter.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color filter according to the present invention is constituted by repeating pixels of a plurality of colors with a pitch of several tens to several hundreds of .mu.m. There are pixels of at least two colors,
Usually, it is composed of three color pixels of red (R), green (G) and blue (B). The pixels are composed of a reflective film formed on the substrate in a predetermined pattern and a color material formed on the reflective film in a predetermined pattern.

FIG. 1 shows a configuration (cross-sectional view) of a color filter according to the present invention. In the color filter of the present invention, a transmissive area 8 and a reflective area 7 exist in one color pixel. One pixel may have both regions, or one pixel may have only one of them, and a plurality of pixels may have both regions. The substrate on which the reflective film 2 is formed may be either a color filter side substrate or a substrate facing the color filter. When the reflection film is formed on the color filter side, the region where the reflection film 2 is formed in the pixel region 9 becomes the reflection region 7, and the reflection film 2 is not formed in the pixel region 9. The area becomes the transmission area 8. When the reflection film is formed on the substrate facing the color filter, the pixel region corresponding to the reflection film formation region of the substrate becomes the reflection region 7, and the pixel region corresponds to the region where the reflection film 2 is not formed. The corresponding pixel area becomes the transmission area 8.

According to the present invention, in at least one color pixel, the low-thickness region 10 having a smaller thickness than the surrounding region and the normal-thickness region 1 exhibiting the same thickness as the transmission region in the reflection region 7.
1 and a transparent region 12 not including a coloring layer. By including the transparent region 12 in the reflection region 7, the same effect as in the case where the film thickness is changed from that of the transmission region 8 can be obtained while using the same color material having the same film thickness. In addition, the inventors have found that by appropriately adjusting the thickness of the transparent region 12 and the volume ratio to the volume of the entire reflection region, it is possible to correct the influence due to the difference in the light source.

If at least one of the plurality of colors has a transparent region, the difference between the transmissive display and the reflective display is reduced, so that the effect of the present invention is exhibited. For other colors, the same color material may be used in the transmission region and the reflection region as in the conventional case, but the thickness of the color material may be changed in the transmission region and the reflection region, and the color material itself may be used. Or the color may be changed by laminating a plurality of color materials. Preferably, the pixel has a transparent region in all colors.

By changing the film thickness d _{1 in the} low film thickness region, the flatness of the colored layer changes. Since the flatness of about d ₁ is larger coloring layer is higher, as compared with the case of providing the through-pinholes, planarization is facilitated by membrane laminated on the colored layer such as an overcoat layer. That is, the overcoat layer having a thinner film thickness can be flattened to the extent that alignment unevenness of the liquid crystal does not occur. The flatness to the extent that liquid crystal alignment unevenness does not occur differs depending on the display mode. For example, a twisted nematic (T
In the case of the N) mode, flatness of about 0.3 μm is required. When d ₁ is larger than 0, there is an effect that flattening is easier than in the case of a penetrating pinhole. However, when the film thickness d ₀ in the normal film thickness region is large and d ₁ is small, the effect of the present invention is small, and the difference between d ₀ and d ₁ is 2 μm.
It is more preferable to set d ₁ to be within m.

When a transparent region is formed along with a reduction in film thickness, the ratio of the volume of the transparent region to the volume of the entire reflecting region (hereinafter referred to as "transparent region ratio") is important. The transparent area ratio is calculated as follows: (d ₀ −d ₁ ) × A ₁ in the pixel is d ₀ × (A ₁
+ A ₀ ). Here, A ₁ is the area of the low-thickness region, and A ₀ is the area of the normal-thickness region. It is preferable to determine the difference between the chromaticity of the transmission area and the chromaticity of the reflection area for each color as small as possible. That is, for at least one color, it is preferable for display that the chromaticity difference δ between the chromaticity (x0, y0) of the transmissive area and the chromaticity (x, y) of the reflective area satisfies the following expression.

Δ = (x−x0) ² + (y−y0) ² ≦ 3 × 10 ^{−3 It is} more preferable that the above expression be satisfied for each color. More preferably, the chromaticity difference δ for one color or all colors satisfies the following expression.

Δ = (x−x0) ² + (y−y0) ² ≦ 1 × 10 ⁻³ Here, the chromaticity of the transmission region 8 means that the above-mentioned color filter transmission region 8 is a microspectrophotometer. The chromaticity of the reflective area 7 is obtained by squaring the spectral spectrum of the colored area 11 and the spectral spectrum of the transparent area 12 in each area at each wavelength. , Normal film thickness region 11 and transparent region 12
Is obtained by taking a weighted average of the areas of

The calculation of the chromaticity takes into account the difference between the light sources. Therefore, the transmission area should be selected from a C light source, a two-wavelength light source, and a three-wavelength light source, and the reflection area should be calculated using a D65 light source. Is preferred. As a two-wavelength light source, a blue LED + yellow phosphor is used. As a three-wavelength light source, a three-wavelength fluorescent tube is used.
RGB-LED, UV LED + RGB phosphor, Organic E
L light source and the like.

Normally, a color filter is composed of three colors of red, green and blue. In this case, a study was made to reduce the chromaticity difference δ between the transmissive area and the reflective area. As a result, regarding the red pixel, 2% or more and 25% or less, more preferably 5%
20% or less and 10% or more 5 for green pixels
It is preferably 0% or less, more preferably 20% or more and 35% or less, and as for the blue pixel, it is 20% or less, more preferably 2% or more and 13% or less.

The transparent area can be divided into a plurality of sub-areas. FIG. 2 is a schematic view of a color filter having the configuration of the present invention and having two sub-regions. When there are a plurality of sub-regions, the total volume of each sub-region in one pixel may be set as the volume of the transparent region. When the thickness d ₀ -d ₁ of the transparent region is large, the total cross-sectional area of the transparent region, that is, the total A ₁ of the cross-sectional areas of the low-thickness region is reduced, and when d ₀ -d ₁ is small, A 1 _It can be adjusted by increasing ₁ . How finely the transparent area is divided is arbitrary. Since there is a limit in the accuracy of the processing, if the division is made too small, the transparent region may not be formed well. On the other hand, if it is too large, phenomena such as flatness of the surface is likely to be impaired, and the display may appear rough, which is not preferable. The area of the sub-region is preferably in the range of 20 to 2000 μm ² . If the distance between adjacent sub-regions is too short, the sub-regions may be connected during processing, and may exceed the preferred area of the sub-region. From the viewpoint of processing accuracy, it was found that the sub-regions could be formed without interference if the distance from the end of the sub-region to the end of another adjacent sub-region was 10 μm or more.

The shape of the transparent region is arbitrary, and may be basically any shape. However,
If the shape includes a very thin portion, the portion may not be formed well. Therefore, a shape that does not include a thin portion, such as a circle, a square, or a rectangle, is preferable.

The arrangement of the sub-regions of the transparent region in the reflection region also has arbitraryness. Basically, any arrangement may be used, but it is preferable to arrange them evenly over the whole area without concentration, from the viewpoint of display uniformity. As described above, the area and thickness of the sub-region, the volume of the entire transparent region,
Since there is a restriction on the distance between the sub-regions, the sub-regions may be arranged within a range satisfying those restrictions.

When pinholes are formed for all the colors of red, green and blue, in order to reduce the chromaticity difference δ, the transparent area ratio in green is made larger than that in other colors, regardless of the selection of the light source. I found it necessary.

Since the surface flatness may be impaired by the formation of the transparent region, it is preferable to form an overcoat layer as a flattening layer on the color material. Examples of the material of the overcoat layer include an epoxy film, an acrylic epoxy film, an acrylic film, a siloxane polymer-based film, a polyimide film, a silicon-containing polyimide film, and a polyimidesiloxane film.

In the patterning of the colored layer by photolithography, the normal film thickness region and the low film thickness region can be simultaneously formed in the reflection region by adjusting the exposure amount of the mask exposure. For example, there is a method of exposing and developing using a photomask having three types of transmittance. The three types of transmittance regions are a light-shielding region having a transmittance of 0%, a complete transmission region having a transmittance of 100%, and a semi-transmission region having a transmittance of 0 to 100%. In exposure, if the average value of the amount of exposure in the semi-transmissive area is adjusted so that the light-shielded area is completely unexposed, the completely transmissive area is completely exposed, and the semi-transmissive area is in the middle between unexposed and fully exposed, development Three types of regions having different solubilities in a liquid can be formed. For example, when a positive resist is used, the completely exposed region is completely dissolved, the semi-transmissive region is partially dissolved, and the thickness of the coating film is smaller than that of the unexposed portion. That is, a low-thickness region can be formed by half-etching the coating film. As a method of forming a semi-transmissive region in a photomask, there is a method of slitting or meshing a part of the photomask.

The substrate used in the present invention may be of any material as long as it is substantially transparent and has rigidity. For example, non-alkali glass, soda glass, a plastic substrate, or the like is used.

The reflecting film according to the present invention may be any as long as it reflects a part of incident light. Usually, an aluminum thin film, a silver / palladium / copper alloy thin film, or the like is used.

The color material used in the present invention may be any material as long as it has a property of transmitting light of any color. Specific examples of the color material include a polymer film in which pigments and dyes are dispersed, a dyed PVA (polyvinyl alcohol), and a SiO ₂ film whose film thickness is controlled to transmit only arbitrary light. Preferably, the polymer film is a pigment-dispersed polymer film, and the polymer film is more preferably a polyimide film or an acrylic film. This is because the color material can be formed by a process that is equal to or simpler than the case where a color material is formed with another material, and further, the heat resistance, the light resistance, and the chemical resistance are more excellent. Above all, a polyimide film has good pattern workability and is advantageous for forming a transparent region. When using a pigment or dye-dispersed polymer film as a color material, apply the paste-like color material uniformly, and then expose,
A pattern is formed by performing photolithography including development.

When a polymer film in which a pigment is dispersed is used as a color material, since the color material is patterned by photolithography, a transparent region can be easily formed by forming a transparent region on a photomask. Becomes possible. The pigment referred to in the present invention is not particularly limited, but among the pigments, light resistance,
Those having excellent heat resistance and chemical resistance are desirable. Specific examples of typical pigments are shown below by color index (CI) numbers.

Examples of yellow pigments include Pigment Yellow 13, 17, 20, 24, 83, 86, 93, 94, 1
09, 110, 117, 125, 137, 138, 13
9, 147, 148, 150, 153, 154, 16
6, 173, 180 and the like. Pigment oranges 13, 31, 36, 38, 4 are examples of orange pigments.
0, 42, 43, 51, 55, 59, 61, 64, 6
5, 71 and the like. Examples of red pigments include Pigment Red 9, 97, 122, 123, 144, and 14
9, 166, 168, 177, 180, 192, 20
6, 207, 209, 215, 216, 224, 24
2, 254 and the like. Examples of purple pigments include Pigment Violet 19, 23, 29, 32, 33,
36, 37, 38 and the like. Examples of blue pigments include Pigment Blue 15 (15: 3, 15: 4, 1).
5: 6), 21, 22, 60, 64 and the like. Examples of green pigments include Pigment Green 7, 1
0, 36, 47 and the like. The pigment may be subjected to a surface treatment such as a rosin treatment, an acidic group treatment, or a basic group treatment, if necessary.

A black matrix may be formed between each pixel. This is a light-shielding region for the purpose of improving the contrast of the liquid crystal display device. As the black matrix, a metal thin film of Cr, Al, Ni or the like (thickness of about 0.1 to 0.2 μm) or a resin black matrix obtained by dispersing a light-shielding material in a resin is usually used. In general, a resin black matrix having no reflection is used so as to serve as a light-shielding film for the reflection area. As the resin, polyimide or acrylic is preferable in terms of heat resistance, chemical resistance and the like. Examples of the black pigment as the light shielding material include Pigment Black 7 and Titanium Black, but are not limited thereto, and various pigments can be used. In addition, pigments that have been subjected to surface treatment such as rosin treatment, acid group treatment, and basic group treatment may be used as necessary.

Next, an example of a liquid crystal display device produced using this color filter will be described. A transparent protective film is formed on the color filter,
A transparent electrode such as a TO film is formed. The transparent conductive film is manufactured through a method such as a dipping method, a chemical vapor deposition method, a vacuum evaporation method, a sputtering method, and an ion plating method. To show a specific example of a typical transparent conductive film,
Indium tin oxide (ITO), zinc oxide, tin oxide, or an alloy thereof can be used. The thickness of such a transparent conductive film preferably does not impair color display, and is preferably 0.5 μm or less. Next, this color filter substrate and a reflective electrode substrate on which a reflective electrode such as a metal vapor-deposited film is formed, and a liquid crystal alignment film further subjected to a rubbing treatment for liquid crystal alignment provided on those substrates, and The substrates are bonded to each other via a spacer for maintaining a cell gap. In addition, on the reflective electrode substrate, in addition to the reflective electrode, a projection for light diffusion, a thin film transistor (TFT) element, a thin film diode (TFD) element, a scanning line, a signal line, and the like are provided. A TFD liquid crystal display device can be created.
Next, after injecting liquid crystal from an injection port provided in the seal portion, the injection port is sealed. Next, a module is completed by mounting an IC driver and the like.

[0030]

EXAMPLES The present invention will be described in more detail with reference to preferred embodiments, but the efficacy of the present invention is not limited by the embodiments used.

Example 1 (Design of Color Filter) A transparent region having a thickness of 1 μm is formed in a reflection region in each of red, green and blue pixels.
Transparent area ratio, that is, the volume of the transparent area (d ₀ −d ₁ ) × A ₁
Are 12%, 26%, and 6%, respectively, in the volume d ₀ × (A ₁ + A ₀ ) of the entire reflection area. The size of the sub-region of the transparent region is red: 17 μmφ (= 227 μm
² ), green: 24 μmφ (= 452 μm ² ), blue: 17 μm
mφ (= 227 μm ² ). Sub-regions were randomly formed in the reflective region. The distance between the sub-region and the adjacent sub-region was 3 μm.

(Preparation of black paste for resin black matrix) 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 4,4'-diaminodiphenyl ether and bis (3-aminopropyl) tetramethyl Disiloxane is reacted with N-methyl-2-pyrrolidone as a solvent to obtain a polyimide precursor (polyamic acid)
A solution was obtained. The carbon black mill base was dispersed at 7000 rpm for 30 minutes using a homogenizer, and the glass beads were filtered to obtain a black mill base, which was diluted with a polyimide precursor solution to obtain a black paste.

(Preparation of Coloring Paste for Forming Color Material) As a red pigment, a pigment prepared by mixing a pigment represented by Pigment Red 209 and a pigment represented by Pigment Orange 38 at a ratio of 85 to 15 was prepared. As a green pigment, a pigment prepared by mixing a pigment represented by Pigment Green 36 and a pigment represented by Pigment Yellow 138 at a ratio of 75:25 was prepared. Pigment Blue 1 as a blue pigment
A pigment represented by 5: 6 was prepared. The pigments were mixed and dispersed in a polyimide precursor solution to obtain three kinds of colored pastes of red, green and blue.

(Preparation of Color Filter) The above black paste was applied by a curtain flow coater on a substrate having an Al reflection film formed on a non-alkali glass substrate (“1737 material” manufactured by Corning), and the hot plate was applied. C. for 10 minutes to form a black resin coating film. Positive photoresist ("SRC-1" manufactured by Shipley Co., Ltd.)
00 ”) with a reverse roll coater, prebaked on a hot plate at 100 ° C. for 5 minutes, and using an exposure machine“ XG-5000 ”manufactured by Dainippon Screen Co., Ltd., through a photomask, to emit 100 mJ / cm ² ultraviolet light. After exposure, the development of the photoresist and the etching of the resin coating film are simultaneously performed using a 2.25% aqueous solution of tetramethylammonium hydroxide to form a pattern, the resist is peeled off with methylcellosolve acetate, and hot The plate was heated at 290 ° C. for 10 minutes to be imidized to form a black matrix, and the thickness of the black matrix was measured to be 1.10 μm.
The OD value was 3.0.

Next, a red paste was applied on a resin black matrix substrate by a curtain flow coater, and dried on a hot plate at 130 ° C. for 10 minutes to form the above-mentioned red resin coating film. After this, as with the black paste,
A positive photoresist was applied by a reverse roll coater and prebaked on a hot plate at 100 ° C. for 5 minutes. Thereafter, exposure was performed by irradiating 100 mJ / cm ² of ultraviolet light through a photomask in which a semi-transmissive region was formed by arranging slits at intervals of 5 μm in 13 μm φ in the reflective region and the reflective region as in the case of black paste. .
Using a 2.25% aqueous solution of tetramethylammonium hydroxide, the development of the photoresist and the etching of the resin coating were simultaneously performed to form a coating pattern having a normal thickness region and a low thickness region in the reflection region. . A pattern was formed, the resist was stripped with methyl cellosolve acetate, and heated at 280 ° C. for 10 minutes on a hot plate to be imidized to form a red pixel. The film thickness was measured.
It was 2 μm.

After washing with water, the above-mentioned green paste was applied to a substrate having a red pixel formed on a resin black matrix,
Green pixels were formed by patterning in the same manner as red pixels using a photomask in which a semi-transmissive region was formed by arranging slits at 5 μm intervals in mφ. When the film thickness was measured, it was 1.3 μm. Further, after washing with water, the above-mentioned blue paste is applied on a substrate having red and green pixels formed on a resin black matrix layer, and slits are formed at intervals of 5 μm in 13 μmφ to form a semi-transmissive region. A blue pixel was formed by pattern processing. When the film thickness of the blue pixel was measured, it was 1.2 μm. Finally, a solution of the curable composition obtained by reacting the hydrolyzate of γ-aminopropylmethyldiethoxysilane with 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride is Spin coating on substrate 260 ° C
For 10 minutes to form an overcoat layer having a thickness of 1.0 μm in a region outside the pixel. At this time, the total film thickness including the overcoat layer in the pixel was 2.4 μm for all of red, green and blue.

(Evaluation of Chromaticity) The spectral transmittance characteristics of the transmission area were measured using a microspectrophotometer “MCPD-2000” manufactured by Otsuka Electronics.
Was measured. Using it, the transmission area is a two-wavelength L
The chromaticity was evaluated on the assumption that the ED light source and the reflection area were D65 light sources.

Example 2 The interval between the slits in the semi-transmissive region of the photomask was set to 2 μm, and the thickness d ₁ of each of the red, blue and green low-thickness regions was set to 0.7.
μm, and the other conditions were the same as in Example 1. The film thickness was 1.2 μm for red and blue, 1.3 μm for green, and the total film thickness including the overcoat layer was 2.4 μm for all colors.

COMPARATIVE EXAMPLE 1 As in the conventional color filter, for all colors, the same material and the same thickness were used in the transmission region and the reflection region, and the slits in the photomask were eliminated, and the film thickness in the transparent region was changed to red and blue. 1.2 μm, green formed 1.3 μm, that is, a completely penetrated pinhole, and the other conditions were the same as in Example 1. The film thickness is 1.2 μm for red and blue, 1.3 μm for green,
The total film thickness including the overcoat layer is 2.4 for all colors
μm.

Example 3 The thickness of the transparent region was set to 0.2 μm for each of red, blue and green.
The other conditions were the same as in Example 1. The film thickness is red,
Blue was 1.2 μm, green was 1.3 μm, and the total film thickness including the overcoat layer was 2.4 μm for all colors.

Example 4 Transparent area ratio, that is, the volume of the transparent area (d ₀ −d ₁ ) × A ₁
Are 2%, 15%, and 3%, respectively, in the volume d ₀ × (A ₁ + A ₀ ) of the entire reflection area, and otherwise are the same as in Example 1. The film thickness is 1.2 for red and blue
μm, 1.3 μm for green, and 2.4 μm for all colors including the overcoat layer.

In Example 1, a color filter having an extremely small chromaticity difference δ between the transmission area and the reflection area was obtained, and good display characteristics were obtained even when used in a liquid crystal display device. Example 2 exhibited the same display characteristics as Example 1. In Comparative Example 1, the color characteristics of the color filter were the same as those in Example 1, but the flatness was as low as about 0.5 μm, and when used in a liquid crystal display device, the orientation of the liquid crystal was disturbed and display unevenness occurred. . In Example 3, the surface of CF after overcoat application was sufficiently flattened and the chromaticity difference δ was small, but the distance between adjacent transparent sub-regions in green was 5
Since the width was reduced to μm, the sub-regions were connected to each other and the area of the sub-region was larger than 2000 μm ² . For this reason, the display quality was lower than that of the first embodiment. In Example 4,
Although the surface of the CF after the overcoat was sufficiently flattened, the chromaticity difference δ was large because the color correction effect in the reflection area was insufficient.

[0043]

According to the present invention, by forming a transparent region in a reflection region, a difference in chromaticity between a transmission region and a reflection region can be reduced, and an inexpensive color filter can be provided without increasing the number of steps. Can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration example 1 (cross-sectional view) of a liquid crystal display device of the present invention.

FIG. 2 is a configuration example 2 (cross-sectional view) of the liquid crystal display element of the present invention.

FIG. 3 is a configuration example 1 (cross-sectional view) of a conventional liquid crystal display element.

FIG. 4 is a configuration example 2 (cross-sectional view) of a conventional liquid crystal display element.

[Explanation of symbols]

 1: color material 2: reflective film 3: backlight light source 4: natural light 5: reflective display light 6: transmissive display light 7: reflective region 8: transmissive region 9: pixel region 10: low film thickness region 11: normal film Thick area 12: Transparent area

Claims (11)

[Claims] At least one color pixel has a reflection area and a transmission area, the reflection area and the transmission area are formed of the same material, and a part of a colored layer of the reflection area has a low film thickness area. In the color filter provided with, when the film thickness d ₁ in the low film thickness region and the film thickness d _{0 in the} normal film thickness region, d ₁ is 0.
A color filter for a transflective liquid crystal display device, wherein d ₀ -d ₁ is larger than μm and smaller than 2 μm. Wherein the area of A ₁ of TeimakuAtsu area, when the area of the normal thickness region represented as A _0, the volume of the transparent regions caused by low membrane thickening in the red pixel (d ₀ -d ₁₎ × the color filter of claim 1, wherein the ratio of a ₁ occupied volume d ₀ × overall reflection area (a ₁ + a ₀₎ is 25% or less than 2%. 3. TeimakuAtsu area of A ₁ of the area, when the area of the normal thickness region represented as A _0, the volume of the transparent regions caused by low membrane thickening in the green pixel (d ₀ -d ₁₎ × the color filter of claim 1, wherein the a ₁ is a percentage of the volume d ₀ × overall reflection area (a ₁ + a ₀₎ is 50% or less than 10%. 4. The area of TeimakuAtsu regions A _1, usually when the area of the film thickness region represented as A _0, the volume of the transparent regions caused by low membrane thickening in the blue pixel (d ₀ -d ₁₎ × the color filter of claim 1, wherein the ratio of a ₁ occupied volume d ₀ × overall reflection area (a ₁ + a ₀₎ is 20% or less. 5. One or more low-thickness regions exist in one pixel, and each low-thickness region has an area of 20 μm ² or more and 2000 μm or more.
The color filter according to any one of claims 1 to 4, wherein the thickness of the color filter is not more than μm ² . 6. The method according to claim 1, wherein two or more low-thickness regions are present in one pixel, and a distance between adjacent low-thickness regions is 10 μm or more. Color filter. 7. A volume d ₀ × (A ₁ +
The ratio of the volume of the transparent region (d ₀ −d ₁ ) × A ₁ occupying A ₀ ) is the largest in the green pixel.
7. The color filter according to any one of items 1 to 6. 8. The color filter for a liquid crystal display device according to claim 1, wherein an overcoat layer is formed on the coloring layer. 9. A transflective liquid crystal display device using the color filter according to claim 1. Description: 10. A pixel has a reflective region and a transmissive region, and for at least one color, the reflective region and the transmissive region are colored by the same material, and a part of the colored layer of the reflective region is formed to have a small thickness. A method for producing a color filter, wherein a transparent region is partially formed in a reflection region by forming a transparent region. 11. The method according to claim 10, wherein in the patterning of the coloring layer by photolithography, half etching is performed by forming a part of the photomask into meshes or slits to form the low-thickness region. Method for manufacturing color filters.