JP4774567B2 - Pattern forming method, color filter manufacturing method, and liquid crystal display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display device excellent in a pattern forming method and display quality, and a color filter capable of manufacturing such a liquid crystal display device.
[0002]
[Prior art]
In recent years, a color liquid crystal display device has attracted attention as a flat display. As an example of a color liquid crystal display device, a black matrix, a colored layer composed of a plurality of colors (usually, three primary colors of red (R), green (G), and blue (B)), a transparent conductive layer (common electrode), and an alignment layer A color filter provided with a TFT array substrate provided with a thin film transistor (TFT element), a pixel electrode and an alignment layer face each other with a predetermined gap, and a liquid crystal material is injected into the gap to form a liquid crystal layer There is. In such a color liquid crystal display device, the gap portion is the thickness of the liquid crystal layer itself, so that high speed response, high contrast ratio, wide viewing angle, etc. required for the color liquid crystal display device can be achieved. Therefore, it is necessary to keep the thickness of the liquid crystal layer, that is, the gap distance between the color filter and the TFT array substrate strictly constant.
[0003]
Conventionally, as a method of determining the thickness of a liquid crystal layer in a color liquid crystal display device, a liquid crystal in which a large number of particles or rod-shaped bodies called spacers made of glass, alumina, plastic, etc. are injected into the gap between a color filter and a TFT array substrate. There is a way to do it. The size of the gap between the two substrates, that is, the thickness of the liquid crystal layer is determined by the size of the spacer.
[0004]
However, in the method for forming the gap between the color filter and the TFT array substrate as described above, the following problems occur in the operation of the color liquid crystal display device. That is, if the density of the spacers scattered on the substrate surface is appropriate and the spacers are not uniformly dispersed on the substrate surface, a gap having a uniform size is not formed over the entire surface of the color liquid crystal display device. . In general, when the amount of scattered spacers (density) is increased, the variation deviation in the thickness of the gap portion is reduced. However, when the amount of scattered spacers (density) is increased, the number of spacers present on the display pixel portion also increases. Then, this spacer becomes a foreign material of the liquid crystal material. The presence of the spacer causes disturbances in the alignment of the liquid crystal molecules regulated by the alignment film, or only the liquid crystal around the spacer has troubles such as the inability to control the alignment by turning the voltage on and off, and the contrast ratio. There has been a problem that display performance is reduced.
[0005]
[Problems to be solved by the invention]
In order to solve such a problem, a color filter having columnar protrusions for determining the gap (thickness of the liquid crystal layer) has been proposed (JP-A-4-318816, etc.). In the color filter as described above, after forming a colored layer and forming a protective layer so as to cover the colored layer, the columnar convex portions are formed at predetermined positions on the black matrix by a photolithography process using a photocurable resin. To form.
[0006]
Therefore, after forming the protective layer, the relief pattern of the columnar protrusions must be formed again through the photolithography process, the color filter manufacturing process is complicated, and throughput, yield, etc. are problematic.
[0007]
The present invention has been made in view of the above circumstances, and has a pattern forming method capable of forming an uneven relief with high accuracy and a columnar convex portion for setting the thickness of a liquid crystal layer, and has excellent display quality. An object of the present invention is to provide a color filter capable of manufacturing a liquid crystal display device and a liquid crystal display device excellent in display quality.
[0008]
[Means for Solving the Problems]
In order to achieve such an object, in the pattern forming method of the present invention, a positive photosensitive resin composition containing an ultraviolet absorber is applied onto a pattern formation object to uniformly contain the ultraviolet absorber. A photosensitive resin layer is formed, and the photosensitive resin layer is exposed through a predetermined mask and developed to form an uneven relief in which the photosensitive resin layer at the exposed portion remains as a recess. .
[0010]
Further, the method for producing a color filter of the present invention includes a substrate, a colored layer composed of a plurality of colors formed in a predetermined pattern on the substrate, and a transparent protective layer formed so as to cover at least the colored layer, In a method for producing a color filter comprising a transparent columnar convex portion formed at a plurality of predetermined sites on the substrate and protruding from the transparent protective layer, the colored layer is formed on the substrate, and then at least the A positive photosensitive resin composition containing an ultraviolet absorber is applied so as to cover the colored layer to form a photosensitive resin layer containing the ultraviolet absorber uniformly, and then a predetermined position for forming a columnar convex portion By exposing and developing the photosensitive resin layer through a mask having a light shielding portion on the exposed portion, the photosensitive resin layer at the exposed portion remains as a concave portion to become the transparent protective layer, and an unexposed portion becomes the columnar convex portion. Department and What it was configured so as to collectively form the columnar projections and the transparent protective layer.
[0012]
The liquid crystal display device of the present invention is a liquid crystal display device comprising a color filter and a counter electrode substrate facing each other, and a liquid crystal layer sealed between the two substrates, wherein the color filter is the above-described manufacturing method of the present invention. It was set as the structure which is a color filter manufactured by (1 ).
[0013]
In the present invention, the ultraviolet absorber contained in the photosensitive resin layer functions to limit the reaction portion in the depth direction to the vicinity of the surface of the photosensitive resin layer at the exposed portion of the photosensitive resin layer. Therefore, an uneven relief in which the exposed portion is a concave portion is formed, and the plurality of transparent columnar convex portions formed together with the transparent protective layer by this pattern forming method have a height necessary as a spacer for setting the thickness of the liquid crystal layer. In addition, it is possible to set the height with high accuracy, and the transparent protective layer flattens the surface of the color filter and prevents elution of components contained in the colored layer into the liquid crystal layer.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the drawings.
[0015]
Pattern Formation Method FIG. 1 is a process diagram for explaining an embodiment of a pattern formation method of the present invention.
[0016]
In FIG. 1, first, a photosensitive resin layer 2 is formed on a pattern object 1 (FIG. 1A). The photosensitive resin layer 2 can be formed by applying a positive photosensitive resin composition containing an ultraviolet absorber.
[0017]
The ultraviolet absorber can be appropriately selected from various known ultraviolet absorbers depending on the ultraviolet light used in the later-described exposure. For example, 4-ethylbiphenyl, anthracene (in the case of ultraviolet light having a central wavelength of 254 nm), 9-fluorenone (In the case of ultraviolet light having a center wavelength of 365 nm). Such an ultraviolet absorber is preferably contained in the photosensitive resin layer 2 in the range of 1 to 15% by weight.
[0018]
The positive photosensitive resin can be selected from various known positive photosensitive resins in consideration of characteristics such as light transmittance and mechanical strength required for the relief formed.
[0019]
The thickness of the photosensitive resin layer 2 can be set as appropriate depending on the height of the uneven relief to be formed, the positive photosensitive resin composition to be used, and the like, but usually a range of 3 to 6 μm is preferable.
[0020]
Next, the photosensitive resin layer 2 is exposed through a photomask M having a desired opening pattern (FIG. 1B). By this exposure, an exposed portion 2a and an unexposed portion 2b are formed in the photosensitive resin layer 2. In the exposed part 2a, the irradiated light is absorbed by the ultraviolet absorber contained in the photosensitive resin layer 2, so that the reaction part 2a 'in the depth direction of the exposed part 2a is limited to the vicinity of the surface of the photosensitive resin layer 2. Is done.
[0021]
Next, the photosensitive resin layer 2 is developed with a developer. In this development, the reaction portion 2a ′ of the exposed portion 2a is removed. Then, the uneven | corrugated relief 3 which consists of the recessed part 3a and the flat part 3b is formed by performing a post-baking process (FIG.1 (C)).
[0022]
In the pattern forming method of the present invention as described above, the depth of the concave portion 3a of the concave / convex relief 3 to be formed is set by appropriately setting the depth of the reaction portion 2a ′ by adjusting the exposure amount, the ultraviolet absorber content, and the like. It can be controlled with high accuracy.
[0023]
Color filter FIG. 2 is a partial plan view showing an example of an embodiment of the color filter of the present invention, and FIG. 3 is a longitudinal sectional view taken along line AA. 2 and 3, the color filter 11 of the present invention includes a substrate 12, a black matrix 13 and a colored layer 15 formed on the substrate 12, and is transparently protected so as to cover the black matrix 13 and the colored layer 15. A layer 16 is formed, and transparent columnar protrusions 17 are formed on the transparent protective layer 16 at a plurality of predetermined locations (five locations in FIG. 2) of the black matrix 13.
[0024]
The substrate 12 constituting the color filter 11 has flexibility such as a transparent rigid material such as quartz glass, pyrex glass, and synthetic quartz plate, or a transparent resin film or an optical resin plate. A transparent flexible material can be used. Among them, Corning 7059 glass is a material having a small coefficient of thermal expansion, excellent dimensional stability and workability in high-temperature heat treatment, and is an alkali-free glass containing no alkali component in the active matrix. Suitable for color filters for color liquid crystal display devices.
[0025]
Further, the black matrix 13 constituting the color filter 11 is provided between the display pixel portions including the colored layer 15 and outside the region where the colored layer 15 is formed. Such a black matrix 13 is formed by forming a metal thin film such as chromium having a thickness of about 1000 to 2000 mm by sputtering, vacuum deposition, or the like, and patterning the thin film, and contains light-shielding particles such as carbon fine particles. A resin layer made of polyimide resin, acrylic resin, epoxy resin, etc. formed and patterned to form a resin layer containing light shielding particles such as carbon fine particles and metal oxide Any of those formed by patterning this photosensitive resin layer may be used.
[0026]
The colored layer 15 has a red pattern 15R, a green pattern 15G, and a blue pattern 15B arranged in a desired pattern shape, and can be formed by a pigment dispersion method using a photosensitive resin containing a desired colorant, Furthermore, it can be formed by a known method such as a printing method, an electrodeposition method, or a transfer method. In addition, for example, by increasing the thickness of the colored layer 15 in the order of the red pattern 15R and the green pattern 15G and the blue pattern 15B in order, an optimal liquid crystal layer thickness may be set for each color of the colored layer 15. .
[0027]
The transparent protective layer 16 is provided to flatten the surface of the color filter 11 and prevent elution of the components contained in the colored layer 15 into the liquid crystal layer, and is a positive type containing an ultraviolet absorber. Made of photosensitive resin. The thickness of the transparent protective layer 16 can be set in consideration of the light transmittance of the material used, the surface state of the color filter 11, and the like, and can be set, for example, in the range of 0.1 to 1.5 μm. it can. Such a transparent protective layer 16 is formed so as to cover at least the colored layer 15 that comes into contact with the liquid crystal layer when the color filter 11 is bonded to the TFT array substrate.
[0028]
Moreover, the columnar convex part 17 acts as a spacer when the color filter 11 is bonded to the TFT array substrate, and is made of a positive photosensitive resin containing an ultraviolet absorber. The columnar protrusions 17 have a certain height so as to protrude from the transparent protective layer 16 in the range of about 2 to 10 μm, and the protrusion amount is required for the liquid crystal layer of the color liquid crystal display device. It can set suitably from thickness etc. The formation density of the columnar protrusions 17 can be set as appropriate in consideration of the thickness unevenness of the liquid crystal layer, the aperture ratio, the shape, material, and the like of the columnar protrusions 17. For example, the red pattern 15R constituting the colored layer 15 In addition, a necessary and sufficient spacer function is expressed at a ratio of one to one set of the green pattern 15G and the blue pattern 15B.
In the illustrated example, the columnar convex portion 17 has a cylindrical shape, but is not limited thereto, and may be a prismatic shape, a truncated cone shape, or the like.
[0029]
Said transparent protective layer 16 and transparent columnar convex part 17 are formed in a lump by the above-mentioned pattern formation method of this invention, Therefore, a ultraviolet absorber is contained in 1-15 weight%.
[0030]
Here, the production of the color filter 11 of the present invention will be described with reference to FIGS. 4 and 5 together with the description of the simultaneous formation of the transparent protective layer 16 and the columnar protrusions 17 by the pattern forming method of the present invention.
[0031]
First, the black matrix 13 is formed on the substrate 12, then the red pattern 15R is formed on the red pattern forming region on the substrate 12, the green pattern 15G is formed on the green pattern forming region, and the blue pattern 15B is formed on the blue pattern forming region. The colored layer 15 is obtained (FIG. 4A). Next, a transparent photosensitive resin composition containing an ultraviolet absorber is applied so as to cover the black matrix 13 and the colored layer 15 to form a photosensitive resin layer 18 (FIG. 4B).
[0032]
The black matrix 13 can be formed as follows, for example. First, a light-shielding layer made of a metal thin film such as chromium formed by sputtering, vacuum deposition, or the like, a resin layer containing light-shielding particles such as carbon fine particles is formed on the substrate 12, and a known material is formed on the light-shielding layer. A photosensitive resist layer is formed using a positive or negative photosensitive resist. Next, the photosensitive resist layer is exposed and developed through a photomask for black matrix, the exposed light shielding layer is etched, and then the remaining photosensitive resist layer is removed to form the black matrix 13.
[0033]
Moreover, formation of said colored layer 15 can be performed as follows, for example. First, a red photosensitive resin layer containing a red coloring material is formed on the substrate 12 so as to cover the black matrix 13, and the red photosensitive resin layer is exposed and developed through a predetermined photomask. Thus, a red pattern 15R is formed in the red pattern forming region on the substrate 12. Thereafter, similarly, the green pattern 15G is formed in the green pattern formation region on the substrate 12, and the blue pattern 15B is formed in the blue pattern formation region on the substrate 12.
[0034]
In addition, the photosensitive resin layer 18 is prepared by using a transparent positive-type photosensitive resin composition containing an ultraviolet absorber, the viscosity of which is optimized, and a black matrix by a known means such as a spin coater or a roll coater. 13 and the colored layer 15 can be formed by coating and drying. As the positive photosensitive resin composition, a photosensitive resin composition prepared in a desired combination from various ultraviolet absorbers and positive photosensitive resins that can be used in the pattern forming method described above can be used.
[0035]
Next, the photosensitive resin layer 18 is exposed through a photomask M ′ for forming columnar protrusions (FIG. 5A). The photomask M ′ to be used includes a light shielding portion at a predetermined position for forming the columnar convex portion 17. By this exposure, a reaction portion is formed in the vicinity of the surface of the photosensitive resin layer 18 in the depth direction at the exposed portion of the photosensitive resin layer 18.
[0036]
Next, the photosensitive resin layer 18 is developed with a developer. By this development, the photosensitive resin layer 18 at the columnar convex portion forming portion (unexposed portion) remains as a pattern of columnar convex portions without being dissolved. In addition, although the exposed part is dissolved to the depth at which the reaction part is formed by exposure, the deeper part of the photosensitive resin layer 18 whose exposure is inhibited by the ultraviolet absorber is not dissolved, but as a pattern of the transparent protective layer. Remain. Then, the color filter 11 of this invention in which the transparent protective layer 16 and the columnar convex part 17 were formed in a lump is obtained by performing heat processing (post-baking) (FIG.5 (B)).
[0037]
In the collective formation of the transparent protective layer 16 and the columnar protrusions 17 as described above, the thickness of the transparent protective layer 16 and the columnar protrusions 17 are adjusted by adjusting the ultraviolet absorber content and the exposure amount of the photosensitive resin layer 18. Can be controlled with high accuracy. In addition, since the transparent protective layer 16 and the columnar projections 17 are formed in one operation by one exposure / development of the photosensitive resin layer 18, the positional accuracy of the columnar projections 17 is extremely high and the process is simple. In the production of the color filter 11, the throughput and yield are good.
The color filter of the present invention may be one in which the black matrix 13 is not provided, and the above-described columnar protrusions 17 are formed at positions corresponding to non-pixel portions.
[0038]
Liquid crystal display device The liquid crystal display device of the present invention has a liquid crystal layer sealed between an opposing color filter and a counter electrode substrate, and includes the color filter of the present invention as a color filter. . For example, an alignment layer is provided on the color filter 11 of the present invention having the columnar protrusions 17 and subjected to alignment treatment (rubbing), and then bonded to the counter electrode substrate. Thus, a gap is formed between the color filter 11 and the counter electrode substrate, and liquid crystal is injected into this gap to form a liquid crystal layer. The gap accuracy between the two substrates is extremely high because the columnar protrusion 17 as described above exhibits a function as a spacer, and the thickness of the liquid crystal layer is constant.
[0039]
【Example】
Next, an Example is shown and this invention is demonstrated further in detail.
[0040]
Example 1
As a substrate for a color filter, a glass substrate (Corning 1737 glass) having a size of 300 mm × 400 mm and a thickness of 0.7 mm was prepared. After this substrate was washed according to a conventional method, a light shielding layer (thickness: 0.1 μm) made of metallic chromium was formed on the entire surface of one side of the substrate by sputtering. Then, a black matrix was formed on the light-shielding layer by performing photosensitive resist coating, mask exposure, development, etching, and resist layer peeling by an ordinary photolithography method.
[0041]
Next, a photosensitive coloring material for red pattern (Color Mosaic CR-7001 manufactured by Fuji Film Orin Co., Ltd.) is applied to the entire surface of the substrate on which the black matrix is formed by spin coating to form a red photosensitive resin layer. And pre-baking (85 ° C., 5 minutes). Thereafter, the red photosensitive resin layer is alignment-exposed using a photomask for a predetermined colored pattern, developed with a developer (diluted solution of developer CD for color mosaic manufactured by Fuji Film Orin Co., Ltd.), and then Post baking (200 ° C., 30 minutes) was performed to form a red pattern (thickness: 1.5 μm) at a predetermined position with respect to the black matrix pattern.
[0042]
Similarly, a green pattern (thickness: 1.5 μm) was formed at a predetermined position with respect to the black matrix pattern using a photosensitive coloring material for green pattern (Color Mosaic CG-7001 manufactured by Fuji Film Olin Co., Ltd.). . Furthermore, a blue pattern (thickness 1.5 μm) was formed at a predetermined position with respect to the black matrix pattern by using a photosensitive coloring material for blue pattern (Color Mosaic CB-7001 manufactured by Fuji Film Orin Co., Ltd.).
[0043]
Next, a transparent positive photosensitive resin composition A having the following composition was applied by spin coating on the substrate on which the colored layer was formed and dried to form a transparent photosensitive resin layer having a thickness of 6 μm.
[0044]
Composition of positive photosensitive resin composition A THMR-iP1800 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) 100 parts by weight 9-fluorenone 5 parts by weight
Next, in a proximity exposure machine using an ultrahigh pressure mercury lamp as an exposure light source, exposure is performed at an exposure amount of 200 mJ / cm ² through a photomask in which a circular light-shielding part having a diameter of 12 μm is provided at the position where the columnar convex part is formed. went.
[0046]
Next, development was performed by immersing the substrate in a developing solution (0.05 wt% potassium hydroxide aqueous solution) for 40 seconds, and after washing, heat treatment (200 ° C., 30 minutes) was performed in a clean oven.
[0047]
By such a series of operations, a transparent protective layer having a thickness of 1.5 μm is formed on the exposed portion, and a transparent columnar convex portion having a height of 4.0 μm is formed on the transparent protective layer on the unexposed portion. As a result, a color filter having a structure as shown in FIGS. 2 and 3 was obtained.
[0048]
(Example 2)
A color filter having a structure as shown in FIGS. 2 and 3 was obtained in the same manner as in Example 1 except that the exposure amount was 500 mJ / cm ² .
This color filter was provided with a transparent columnar convex part having a height of 4.5 μm and a transparent protective layer having a thickness of 1.0 μm formed together with the convex part.
[0049]
(Example 3)
As a positive photosensitive resin composition, a positive photosensitive resin composition B having the following composition is used, and exposure is performed at an exposure amount of 200 mJ / cm ² using a proximity exposure machine equipped with a low-pressure mercury lamp as an exposure light source. A color filter having a structure as shown in FIGS. 2 and 3 was obtained in the same manner as in Example 1 except that the procedure was performed.
[0050]
Composition of positive photosensitive resin composition B: AZ DX1100 (manufactured by Hoechst Japan Co., Ltd.) ... 100 parts by weight · 4-ethylbiphenyl ... 5 parts by weight This color filter is a transparent column having a height of 4.0 µm. A convex portion and a transparent protective layer having a thickness of 1.0 μm formed together with the convex portion were provided.
[0051]
【The invention's effect】
As described above in detail, according to the present invention, the reaction part in the depth direction of the exposed portion is limited to the vicinity of the surface of the photosensitive resin layer by the ultraviolet absorber contained in the photosensitive resin layer, With a color filter having a transparent protective layer and transparent columnar protrusions that are collectively formed by the pattern forming method of the present invention, a plurality of transparent columnar reliefs can be easily formed by development. The convex portion has a height required as a spacer for setting the thickness of the liquid crystal layer, and can be formed integrally with the transparent protective layer by one exposure of the photosensitive resin layer, so that the positional accuracy is extremely high. It can also be applied to a color liquid crystal display device that requires high accuracy in controlling the thickness of the layer, and the transparent protective layer flattens the surface of the color filter and applies components contained in the colored layer to the liquid crystal layer. Since prevent output enables excellent display quality reliable color liquid crystal display device, such a color filter, the step also are those simple, throughput, and yield is good at manufacturing. And since the liquid crystal display device using such a color filter of the present invention has a constant thickness of the liquid crystal layer, it has good display performance such as high-speed response, high contrast ratio, wide viewing angle, etc. Become.
[Brief description of the drawings]
FIG. 1 is a process diagram for explaining an embodiment of a pattern forming method of the present invention.
FIG. 2 is a partial plan view showing an example of an embodiment of a color filter of the present invention.
3 is a longitudinal sectional view taken along line AA of the color filter of the present invention shown in FIG.
FIG. 4 is a process diagram for explaining a production example of a color filter of the present invention.
FIG. 5 is a process diagram for explaining a production example of a color filter of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Pattern to-be-formed object 2 ... Photosensitive resin layer 2a ... Exposure part 2a '... Reaction part 2b ... Unexposed part 3 ... Uneven pattern 3a ... Concave part 3b ... Flat part 11 ... Color filter 12 ... Substrate 13 ... Black matrix 15 ... Colored layer 16 ... Transparent protective layer 17 ... Columnar protrusion 18 ... Photosensitive resin layer M, M '... Photomask

Claims (3)

A positive photosensitive resin composition containing an ultraviolet absorber is applied onto the pattern formation object to form a photosensitive resin layer containing the ultraviolet absorber uniformly, and the photosensitive resin layer is applied to a predetermined mask. The pattern forming method is characterized by forming a concavo-convex relief in which the photosensitive resin layer at the exposed portion remains as a concave portion by exposing and developing the film. A substrate, a colored layer composed of a plurality of colors formed in a predetermined pattern on the substrate, a transparent protective layer formed so as to cover at least the colored layer, and formed at a plurality of predetermined sites on the substrate; In the manufacturing method of the color filter provided with the transparent columnar convex part protruding from the transparent protective layer,
A photosensitive resin layer that uniformly contains an ultraviolet absorber by forming the colored layer on the substrate and then applying a positive photosensitive resin composition containing an ultraviolet absorber so as to cover at least the colored layer. Next, the photosensitive resin layer is exposed and developed through a mask having a light-shielding portion at a predetermined position for forming columnar convex portions, so that the photosensitive resin layer at the exposed portion remains as a concave portion. Then, the transparent protective layer is formed, the unexposed portion becomes the columnar convex portion, and the columnar convex portion and the transparent protective layer are collectively formed.   A liquid crystal display device comprising a color filter and a counter electrode substrate facing each other and a liquid crystal layer sealed between the substrates, wherein the color filter is a color filter manufactured by the manufacturing method according to claim 2. A liquid crystal display device.

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