JPH11174221A - Production of color filter and color liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a color filter having almost uniform film thickness by including a second exposure process for exposing a photosensitive material again after the photosensitive material is developed and before baked. SOLUTION: After development, the photosensitive material is irradiated with UV rays under specified exposure conditions for post-exposure (second exposure process) of a film 3r of a color phase R (process c). After the post- exposure, the film is subjected to post-baking by using an oven or the like to thermally polymerize and harden the film 3r of the color phase R (process d). By forming a color filter layer 3 in this procedure, the difference in film thickness of the color filter layer 3 is controlled to <=0.1 μm. Namely, by controlling the quantity of exposure light in the second exposure process for exposing again the photosensitive material after development and baking, spreading of the area where photopolymn. is completed in the film thickness direction in the photosensitive material can be controlled. Therefore, reduction in film thickness after baking can be controlled and the film thickness is made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color liquid crystal display device and a method for manufacturing a color filter provided in the color liquid crystal display device.

[0002]

2. Description of the Related Art A liquid crystal panel provided in a color liquid crystal display device having a color filter has, for example, a transparent substrate made of a pair of glass and the like disposed opposite to each other, and a substrate facing surface of one transparent substrate. In addition, a black mask layer, a color filter layer, an overcoat layer, a display electrode, and an alignment film are formed in this order, and the display electrode, an insulating film, and an alignment film are formed in this order on the substrate facing surface of the other transparent substrate. Is formed.

[0003] These transparent substrates are bonded together with a sealing material containing glass beads disposed on the periphery of the substrate via plastic beads for cell gap control, and the transparent substrate surrounded by the sealing material. Liquid crystal is sealed in the gap to form a liquid crystal layer. The configuration of such a liquid crystal panel is one configuration example.

The above-mentioned color filter layer, which is one element constituting a color liquid crystal display element, has red (R), green (G) and blue (G) corresponding to each pixel formed by both display electrodes. It is composed of three types of hue films B), and the film thickness is generally 1.0 μm to 1.5 μm.

An example of a method of manufacturing such a color filter layer will be described with reference to FIGS. 18A to 18D. First, as shown in FIG. A negative photosensitive resin material layer 34r in which a pigment of one of R, G, and B (here, R) is dispersed is coated on the transparent substrate 31 on which is formed by spin coating, printing, and film laminating. It is formed with a predetermined film thickness by the method described above. And
Using a mask 33r, UV (ultraviolet) light of a specific wavelength is exposed only at predetermined locations from the surface.

Next, as shown in FIG. 1B, the resultant is developed to form a first color hue film 32r at a predetermined location, and then, as shown in FIG. And post-baking for thermal polymerization and curing.

The above steps are similarly repeated for the second color and the third color, and finally, the main baking is performed. This allows
As shown in FIG. 3D, a color filter layer 32 having R, G, and B hue films 32r, 32g, and 32b arranged at predetermined positions is formed.

In addition to the above-described manufacturing method, R, R formed by using a photosensitive resin material containing a UV absorbing material is used.
A photosensitive resin light-shielding material is formed on the G and B hue films by a spin coating method, a printing method, a film laminating method, or the like,
U, R, G, B hue film UV absorber
There is also a method of irradiating V light to form a black mask layer.

When the photosensitive resin material is formed by a spin coating method or a printing method, the thickness of the color filter layer thus formed is determined by an initial formed film thickness (after coating and immediately after printing) and a subsequent post-baking. And in the case of the film lamination method,
It is determined by the initial film thickness and the subsequent film baking by post-baking and main baking. Therefore, the variation in the thickness of the color filter layer is determined by the variation in the initial film thickness or the variation in the initial film thickness and the variation in the temperature distribution during baking.

On the other hand, in the above-described color liquid crystal display device, the twist angle of liquid crystal molecules between a pair of transparent substrates is set at 18 degrees.
An STN (super twisted nematic) type liquid crystal display element set at 0 ° to 360 ° has been attracting attention because of its quick response. However, in the case of the STN type liquid crystal display element,
Since the display quality is extremely deteriorated due to the thickness of the liquid crystal layer, that is, the variation of the cell gap, the variation of the thickness of the color filter layer becomes a problem.

Therefore, conventionally, in the case of an STN type color liquid crystal display device, a 1.0 μm thick film is formed on the color filter layer.
By forming an overcoat layer of about m to 3.0 μm, the thickness of the color filter layer surface is made uniform (leveling).
It is carried out.

In general, a negative photosensitive resin material used for forming a color filter layer undergoes a shape change as shown in FIG. 19 after each process of exposure → development → post bake. That is, as shown in FIG. 3A, the photopolymerization reaction proceeds in the portion near the surface of the photosensitive resin material layer 34 due to the exposure, but the UV light is attenuated inside the photosensitive resin material layer 34 by the UV absorber. However, the photopolymerization reaction becomes insufficient and the photopolymerization reaction is not sufficiently completed. It should be noted that increasing the irradiation amount of UV light here results in over-exposure, which results in poor finished development, variations in dot size, and the like, and thus has a limit.

Subsequently, as shown in FIG. 1B, when development is performed, a portion where the photopolymerization reaction is insufficient is tapered by side etching. Thereafter, as shown in FIG. 3 (c), when post-baking is performed, the thermal polymerization reaction of the photopolymerization reaction in the lower layer, which is insufficient, proceeds, and the entire structure is deformed into a kamaboko shape.

[0014]

On the other hand, in recent years, high display quality, high characteristics, and high reliability have been required for liquid crystal display elements, especially for STN type color liquid crystal display elements, and the contrast is 30: 1 or more. Has been requested. In particular, among the above-mentioned demands, there is a demand for a stronger improvement in display quality of halftones than users.

Under such circumstances, the above-described conventional method for manufacturing a color filter layer has a limit in reducing the difference in film thickness.
It is becoming impossible to respond to requests from users.

That is, in the conventional method of manufacturing a color liquid crystal display element, the thickness of the color filter layer after the main baking is set to about 1.
When the thickness is from 0 μm to 1.5 μm, there is a variation of ± 0.2 μm to 0.3 μm in the case of the spin coating method and the printing method.
However, since each of the R, G, and B hue films is individually subjected to the respective steps of exposure, development, and post-baking, even in the case of micro (between the R, G, and B hue films), macro (the entire display area) In the case of (1), for example, when it is attempted to form TYP of 1.5 μm, a film thickness difference of 1.2 μm to 1.8 μm (0.6 μm difference) occurs. Further, a variation in the film thickness due to a variation in the firing temperature distribution is added to this.

In the film laminating method,
In the process of producing the photosensitive colored film material,
In order to produce a colored film laminate by applying a photosensitive resin material to the support, the thickness variation of the colored layer of the finished film is about ± 0.15 μm.
Since the post-baking is repeated to form the R, G, and B color layer films, the color filter layers vary in thickness of ± 0.1 to 0.2 μm after the main baking.

In the STN type color liquid crystal display device,
Optical characteristics and display quality (especially halftone display quality) are greatly affected by variations in cell gaps, both macroscopically and microscopically.
When an N-type color liquid crystal display element is manufactured, a color filter layer of 1.5 μm design has a thickness of 1.2 μm to 1.8 μm.
If there is a variation in the thickness of the color filter layer of m (0.6 μm difference), the cell gap is 5.91 μm to 6.09 μm (0.18 μm difference) even after the overcoat treatment.
There will be variations between the G and B pixels.

As a result, when the liquid crystal is turned on at Voff, the liquid crystal shutter effect varies between the R, G, and B pixels, so that the black level is deteriorated and the contrast is not improved. Also, when the dot shape of the R, G, and B hue films is in a semicylindrical shape, a difference occurs in the cell gap between the peaks and the valleys, and the contrast cannot be improved.
Further, with respect to the display quality of the halftone, since the variation in the cell gap appears as a difference in the rise of the liquid crystal molecules, for example, in a 6 μm STN type liquid crystal display element, the G hue film is +0.05 μm, and the R, B If the hue film is higher than the hue film, the halftone becomes greenish, which causes a problem that the user has an abnormal color tone.

FIG. 20 shows the relationship between the cell gap variation and the contrast in the STN liquid crystal display device. The contrast is determined by the phase difference of the polarizer disposed outside the liquid crystal panel and the phase difference of the liquid crystal panel. The phase difference of the liquid crystal panel is d × Δn (d: cell thickness,
Δn: birefringence of liquid crystal).

When the cell gap of the liquid crystal panel fluctuates,
The phase difference of the liquid crystal panel changes, and the polarized light (elliptically polarized light) passing through the liquid crystal panel changes, so that the shutter effect of the polarizing plate is weakened and the contrast is reduced. That is, in a panel system designed with a TYP cell thickness (here, 6.0 μm), the cell gap is thicker or thinner, and the contrast and contrast are reduced.

FIGS. 21 (a) and 21 (b) show the relationship between the difference in the thickness of the R, G, and B hue films and the display quality (halftone, especially the DOS screen). Here, G is set with reference to the R hue film 32r.
Shows the quality when the thickness of the hue film 32g varies.

The R hue film 32r and the G hue film 32
g, the cell gap of the pixel of that hue is R
The portion of the G hue film 32g is thinner than the portion of the hue film 32r. That is, considering the VT curve (voltage vs. transmittance characteristics), the G pixel has a higher R
Since the cell gap is thinner than that of the pixel, the rise of the liquid crystal is accelerated, and the light of G is emitted as a halftone, so that the image becomes greenish.

The film thickness difference (R-G) in FIG.
This is the difference in film thickness after the overcoat treatment in which the overcoat layer is provided on the color filter layer, and is equal to the difference in cell gap.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for manufacturing a color filter capable of manufacturing a color filter having a film thickness more uniform. It is another object of the present invention to provide a color liquid crystal display device having high contrast and excellent halftone display quality by manufacturing a color liquid crystal display device using the manufacturing method.

[0026]

According to a first aspect of the present invention, there is provided a method of manufacturing a color filter, comprising: forming a color filter using a negative photosensitive material; In the method for manufacturing a color filter having a hue film, in the step of preparing each hue film, a first exposure step of exposing the photosensitive material from the front side before development and drawing a pattern on the photosensitive material, and after development A second exposure step of exposing the photosensitive material again before baking the photosensitive material.

According to this, when the photosensitive material is, for example, a photosensitive resin material, the amount of exposure in the second exposure step of exposing the photosensitive material again after development and before baking is adjusted, so that the photosensitive material is exposed. The extent of the photopolymerization completion region in the thickness direction of the conductive resin material can be controlled. This makes it possible to control the film reduction rate after firing and make the film thickness uniform.

In addition, the exposure in the second exposure step after development expands the photopolymerization reaction region in the thickness direction of the photosensitive resin material, and the phenomenon that the dot deformation after firing becomes a semi-cylindrical shape is reduced. Therefore, this also makes it possible to reduce the unevenness of the film thickness distribution and make the film thickness of the color filter uniform.

As a result, when the total thickness of the color filters is, for example, 1.0 to 1.5 μm,
After the overcoat treatment, the thickness can be reduced to 0.05 μm or less.

Since the exposure in the second exposure step is after development, it can be performed from the front side of the photosensitive material, from the back side via the transparent substrate, or from both the front and back sides. It works effectively in the film thickness direction.

According to a second aspect of the present invention, there is provided a method for manufacturing a color filter, wherein the color filter is formed using a negative photosensitive material and has a hue film of at least two colors. In the method for producing a hue film, a first exposure step of exposing the photosensitive material from the surface side before development and drawing a pattern on the photosensitive material before development, and a step of exposing the photosensitive material after the first exposure step Before firing the material,
A second exposure step of exposing the photosensitive material again, wherein the second exposure step in the step of producing a hue film other than the hue film formed lastly includes a front side or a rear side of the transparent substrate after development. , And only in the second exposure step in the manufacturing step of the hue film to be formed last, the light is exposed from the back side of the transparent substrate before development.

According to this, similarly to the configuration of the first aspect,
When the photosensitive material is, for example, a photosensitive resin material, by adjusting the exposure amount in the second exposure step, it is possible to control the film reduction rate after baking to make the film thickness uniform, and The phenomenon that the dot deformation of the dot shape becomes a kamaboko shape is also alleviated.

In particular, the photosensitive material is exposed to light from the substrate side of the transparent substrate (second exposure step) before development, particularly for only the hue film formed last. In this case, since the already formed hue film acts as a mask for the last hue film, the second exposure step can be performed before development. According to such a procedure, the pinhole defect occurring in the already formed hue film can be corrected by the photosensitive material for forming the last hue film simultaneously with the formation of the last hue film.

According to a third aspect of the present invention, there is provided a color filter manufacturing method according to the first or second aspect, wherein the photosensitive material receives more exposure energy in the second exposure step than in the first exposure step. It is characterized by:

Since the exposure in the second exposure step is performed directly after development or using the already formed hue film as a mask, the first exposure for drawing a pattern is performed.
Even if the irradiation amount of light is increased from the exposure in the exposure step, there is no possibility of overexposure. Therefore, by increasing the exposure energy in the second exposure step and reliably achieving the photopolymerization reaction in the thickness direction of the photosensitive material, the thickness of the color filter can be made more uniform and the thickness difference can be reduced.

A color liquid crystal display device according to a fourth aspect of the present invention includes a color filter manufactured by the method according to the first or second aspect, and has a super twisted nematic liquid crystal molecule arrangement having a twist angle of 180 ° to 360 °. It is characterized by comprising a liquid crystal panel.

The color filter manufactured by the manufacturing method of claim 1 or 2 has a thickness difference of 0.05 μm as described above.
The following can be realized. Therefore, a super-twisted nematic liquid crystal display device provided with such a color filter,
Contrast and halftone display quality can be improved, and extremely excellent display characteristics and display quality can be obtained.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention, ST
The N-type color liquid crystal display device will be described below with reference to FIGS.

As shown in FIG. 3, the liquid crystal panel provided in the present STN-type color liquid crystal display device has a pair of transparent substrates 1 and 2 made of glass or the like disposed facing each other.
On a substrate facing surface of one transparent substrate 1, a black mask layer 5, a color filter layer 3, an overcoat layer 6, a display electrode 7a, and an alignment film 8a are formed in this order, and a substrate facing surface of the other transparent substrate 2 is formed. In addition, a display electrode 7b, an insulating film 9, and an alignment film 8b are formed in this order.

The display electrodes 7a and 7b form a stripe pattern orthogonal to each other, and the display electrodes 7a and 7b
A pixel serving as one unit of display is formed at each intersection of. The color filter layer 3 is formed of a three-color hue film of R, G, and B arranged corresponding to each pixel. The thickness of the color filter layer 3 is, for example, 1.
Assuming that the thickness is set between 0 μm and 1.5 μm, a film thickness difference of about 0.1 μm in the completed state of the color filter layer 3 and a film thickness of about 0.1 μm in the completed state of the overcoat layer 6 are produced by a manufacturing method described later. It is manufactured with a thickness difference of 0.05 μm or less.

The overcoat layer 6 serves to smooth the unevenness of the surface of the color filter layer 3 to absorb the difference in film thickness of the color filter layer 3, and has an absorption rate of about 70%.

The black mask layer 5 is made of, for example, Cr or a photosensitive resin light-shielding material. The black mask layer 5 partitions the hue films of the color filter layer 3 in order to prevent mixing of the R, G, and B hue films. It is formed as follows.

The above transparent substrates 1 and 2 are bonded together via a sealing material 12 containing glass beads 11 disposed on the periphery of the substrate via plastic beads 10 for cell gap control, and are surrounded by the sealing material 12. A liquid crystal is sealed in the gap between the glass substrates 1 and 2, and a liquid crystal layer 13 is formed.

The liquid crystal molecules of the liquid crystal layer 13 are
-A helical structure is formed between the two with a twist angle of 180 ° to 360 °. Then, two polarizing plates (not shown) are provided so as to sandwich the liquid crystal panel having such a configuration.

Next, a method of manufacturing the color filter layer 3 in the liquid crystal panel will be described with reference to FIGS. 1 (a) to 1 (m) are cross-sectional views showing respective manufacturing steps of the color filter layer 3, and FIG. 2 is a process diagram showing a manufacturing flow.

First, as shown in FIG. 1 (a), R, G, R and G are applied to a glass substrate 1 on which a black mask 5 of Cr or the like is formed.
A negative photosensitive resin material layer 14r in which one color of B, here R pigment is dispersed, is coated with a spin coating method, a printing method,
A film having a predetermined thickness is formed by a film laminating method or the like (P1 in FIG. 2), and UV light of a specific wavelength is exposed only at predetermined positions from the surface using a mask 15r (main exposure: first exposure step) (FIG. 2 P2). Subsequently, as shown in FIG. 1B, development is performed to form an R photosensitive resin material layer 14r at a predetermined location, and first, an R hue film 3r is formed (P in FIG. 2).
3).

In the conventional method, post baking is performed thereafter. In the present invention, after development, as shown in FIG.
By irradiating UV light under predetermined exposure conditions, the R hue film 3r
Then, post exposure (second exposure step) is performed (P4 in FIG. 2).
This post-exposure may be performed from the front side of the R hue film 3r, from the back side (that is, the back side of the substrate), or from both the front and back sides. However, since the exposure from the back side is performed through the transparent substrate 1, it is necessary to considerably increase the exposure amount as compared with the case where the exposure is performed from the front side. In this regard, by performing the exposure from both sides, the exposure amount can be reduced as compared with the exposure from the back side.

When post-exposure is completed in this way, FIG.
As shown in FIG. 2D, post-baking is performed using an oven or the like to thermally polymerize and cure the R hue film 3r (P in FIG. 2).
5). Next, as shown in FIG.
A negative photosensitive resin material layer 14g in which a pigment of one of the remaining colors G, B, here, G is dispersed, is formed on the transparent substrate 1 on which r is formed to a predetermined thickness (FIG. 2 P6),
Using a mask 15g, UV light of a specific wavelength is exposed only at predetermined positions from the surface (P7 in FIG. 2), and as shown in FIG. 1 (f), developed to form a G photosensitive resin material layer 14g. To form a G hue film 3g (P in FIG. 2).
8).

Next, as shown in FIG. 1 (g), the hue film 3g is post-exposed by irradiating UV light under predetermined exposure conditions (P9 in FIG. 2). Note that this post-exposure
From the front side, the back side, or both the front and back sides of the hue film 3g. Thereafter, as shown in FIG. 1H, post-baking is performed using an oven or the like to thermally polymerize and cure the G hue film 3g (P10 in FIG. 2).

Similarly, as shown in FIGS. 1 (i) to 1 (l), a negative photosensitive resin material layer 1 in which a B-color pigment is dispersed is used.
4b is formed with a predetermined thickness, and the remaining B hue film 3b is formed using the mask 15b (P11 to P1 in FIG. 2).
5). Then, finally, as shown in FIG. 1 (m), the main baking is performed using an oven or the like (P16 in FIG. 2). Thus, the color filter layer 3 is formed.

By forming the color filter layer 3 in such a procedure, it is possible to control the thickness difference of the color filter layer 3 after the main baking to 0.1 μm or less.
Hereinafter, the reason will be described. The process of manufacturing a color filter layer using a negative photosensitive resin material is usually performed by a main exposure →
Development → post-baking is repeated for each of the R, G, and B hue films. After the R, G, and B hue films are completed, the main baking is performed to form a predetermined color filter layer.

FIG. 4 shows the relationship between the reduction of the R, G, and B hue films due to the post-baking and the main baking. As can be seen from FIG. 4, the R, G, and B hue films are reduced in thickness due to the thermal polymerization reaction caused by post-baking and main baking.
And usually, in the final stage, the degree of polymerization is improved (baked).
Therefore, the main bake temperature is set to be higher than the post-bake temperature, so that film reduction occurs in two stages as shown in FIG.

Further, in the thermal polymerization reaction such as post-baking and main baking, a competition reaction between the thermal decomposition of the monomer and the thermal polymerization occurs, so that the unevenness in the temperature distribution directly changes the degree of polymerization, and as a result, the film thickness of the color filter layer becomes large. Distribution unevenness occurs.

FIG. 5 shows the post-baking of each color filter (CF) layer and the film after completion of the main baking when post-exposure is performed from the front side after development and when post-exposure is not performed in the conventional manner. The thickness change rate is shown. From the film thickness change rate, the film reduction rate and variation = film thickness distribution unevenness can be found.

As can be seen from FIG. 5, when post-exposure is performed from the front side after development, the photopolymerization completed region in the thickness direction of the color filter layer is expanded, that is, the heat polymerization reaction region in post-baking or main baking is narrowed. Therefore, the change rate of the film thickness of the color filter layer becomes small, and the film reduction rate and the film thickness unevenness decrease.

Thus, by adjusting the amount of post-exposure exposure, it is possible to control the spread of the polymerization completed region in the film thickness direction of the color filter layer, thereby controlling the film reduction rate, and reducing the film thickness distribution unevenness. It becomes possible.

As shown in FIGS. 6A to 6D,
When post-exposure is performed after development, the color filter layer 3
The photopolymerization reaction region in the film thickness direction is widened, the deformation of the dots after post-baking is reduced, and the shape of the semicircular shape is reduced.
Therefore, this also makes it possible to reduce unevenness in the film thickness distribution.

The effect of the post-exposure can be obtained by performing the post-exposure from the front side (front exposure), from the back side (back exposure), or from both the front and back sides (double-side exposure). Since each of them works effectively in the film thickness direction, it can be obtained similarly.

However, in the case of post-exposure from the front side, as shown in FIG. 7A, the polymerization of the portion of the color filter layer 3 on the transparent substrate 1 side is weak. During this baking (high temperature, long time)
There is a possibility that air bubbles may be generated on the side due to film dripping and air bubbles may be generated. The bubbles are defective because they burst in subsequent steps. Therefore, in post exposure from the front side, the development conditions are narrowed and the development margin is narrow in order to avoid such defects.

On the other hand, in the case of post-exposure from the back side, as shown in FIG. 3B, polymerization of the portion on the side of the transparent substrate 1 is progressing.
During baking, it is unlikely that bubbles will be generated due to film dripping,
Wide development margin. However, since the exposure is performed through the transparent substrate 1, the required exposure amount is larger than the exposure from the front side, and the production tact becomes slow.

On the other hand, exposure from both front and back sides
Since the exposure amount can be reduced as compared with the exposure from the back side only, there is an effect that the production tact can be made faster while taking advantage of the above-described exposure from the back side.

Further, in the flow of FIG. 2, post exposure is performed after development for all of the R, G, and B hue films 3r, 3g, and 3b. When post-exposure is performed on the hue film 3b, since the already formed R and G hue films 3r and 3g act as a mask, the post-exposure may be performed through the transparent substrate 1 from the back side before development, or Main exposure (front exposure) and post exposure (back exposure) can be performed simultaneously.

By adopting such a procedure, the pinhole defect occurring in the R and G hue films 3r and 3g can be reduced at the same time as the formation of the B hue film 3b and the B photosensitive resin material layer 14b.
Can be filled and corrected, and the non-defective rate can be improved.

The setting of the post-exposure conditions for controlling the film reduction rate of the color filter layer described above is based on the prior art as shown in FIG. 8, that is, the R, G, and B hues without post-exposure. The film thickness change when the film is formed is obtained, and the relationship between the post exposure amount and the film thickness of the R, G, and B hue films after the main baking is evaluated using the post exposure amount as a parameter as shown in FIG. A basic experiment may be performed to obtain experimental data, and simulation may be performed so that the thicknesses of the R, G, and B hue films 3r, 3g, and 3b in the color filter layer 3 are uniform.

Since post-exposure has already been performed after development, there is no possibility of overexposure even if the irradiation amount of UV light is increased beyond the exposure amount (exposure energy) of the main exposure. Therefore, in order to surely achieve the photopolymerization reaction in the thickness direction of the color filter layer 3 by the post exposure, it is preferable that the exposure amount is larger than the exposure amount of the main exposure.

As described above, in the present STN type color liquid crystal display device, the R, G, B hue films 3r of the color filter layer 3 are formed.
When forming 3g and 3b in order, post-exposure is performed after development and before post-baking to control the film reduction rate for each hue film.

Thus, the R, G and B hue films 3r and 3r
g, 3b, the color filter layer 3
When the thickness of the film is 1.0 to 1.5 μm, the thickness difference is 0.1 μm.
m, and the film thickness difference after the overcoat treatment can be made 0.05 μm or less. As a result, even in the STN type in which the cell gap control is difficult, the contrast is high and the halftone display quality can be improved.

[0068]

Embodiment 1 FIG. 10 shows a flow of manufacturing a color filter layer of an STN type color liquid crystal display device according to a first embodiment of the present invention. FIG. 11 shows the dot shapes of the R, G, and B hue films 3r, 3g, and 3b of the color filter layer 3 manufactured in such a process.

Referring to FIG. 1 described above, a transparent substrate 1 made of glass on which a black mask layer 5 in which a metal such as Cr is formed in a matrix is disposed, a negative containing a UV absorber made by Fuji Film R hue film 3r having an initial film thickness of 1.90 μm using a photosensitive resin material film
Was formed under the conditions shown in Table 1 by a film lamination method using a G hue film 3g having an initial film thickness of 1.95 μm and a B hue film 3b having an initial film thickness of 2.10 μm. The I line in Table 1 is UV light having a wavelength of 365 nm.

[0070]

[Table 1]

The post-exposure conditions are defined by using the film thickness of each hue film after the completion of development in the case where the color filter layer is manufactured by the conventional technique in FIG. 8 and the post-exposure conditions in FIG. 9 as parameters.
From the data from the basic experiment which evaluated the relationship between the post-exposure condition and the finished film thickness, the R, G, and B hue films 3r and 3g were obtained.
・ Each film thickness of 3b is made uniform (in this case, 1.7 μm).
where m is the condition under which the film thicknesses of the R, G, and B hue films 3r, 3g, and 3b are uniformed). Here, in all three types of R, G, and B, the post exposure was surface exposure from the surface.

When the surface of the color filter layer 3 produced under these conditions was measured at six points with a surface roughness meter, the results are as shown in Table 2.

[0073]

[Table 2]

Then, an overcoat layer 6 was further formed, and its surface was measured with a surface roughness meter as shown in FIG.
A total of 20 points are measured on 4 substrates as 5 points per substrate, and GR, BR are determined based on the height of the R hue film 3r.
Table 3 shows the result of calculating the average value, the maximum value, and the minimum value by summing up the data as the film thickness difference.

[0075]

[Table 3]

From Table 3, it was confirmed that the average value was within 0.01 μm, and the variation (MAX-MIN) was about 0.05 μm, which means that the finish was extremely accurate.

Using the color filter layer 3 manufactured under these conditions, a STN-type color liquid crystal display device as shown in FIG. 3 was manufactured, and the optical characteristics were confirmed. It improved about 10 to 15%. In addition, the display quality also achieves a uniform display quality especially in halftone display because the variation in the thickness of the in-plane color filter layer 3 is small, and a high-speed response type which is particularly important in the future STN type color liquid crystal display element ( Even with a cell thickness of 5 μm or less), uniform display quality could be achieved.

Embodiment 2 FIG. 13 shows a flow of manufacturing a color filter layer of an STN-type color liquid crystal display device according to a second embodiment of the present invention. FIG. 14 shows the dot shapes of the R, G, and B hue films 3r, 3g, and 3b of the color filter layer 3 manufactured in such a process.

Here, the same substrate, R,
G and B films were prepared, and the color filter layer 3 was formed under the conditions shown in Table 4. The post-exposure conditions were determined from a basic experiment, as in Example 1, but here, back exposure was used. In the case of back exposure, since the transparent substrate glass exists, the exposure amount is considerably increased as compared with the front exposure of the first embodiment. Post-exposure was performed on only the finally formed hue film 3b before development. Since the R, G, and B hue films 3r, 3g, and 3b contain a UV absorber,
Post-exposure for forming the final hue B hue film 3b can be performed before development.

[0080]

[Table 4]

The surface of the color filter layer 3 produced under these conditions was measured at 6 points with a surface roughness meter in the same manner as in Example 1, and the results are as shown in Table 5.

[0082]

[Table 5]

Then, an overcoat layer 6 is further formed, and the surface thereof is measured with a surface roughness meter at 5 points per substrate and 4 substrates for a total of 20 points. Based on the height of the R hue film 3r, The data was tabulated as the film thickness difference between GR and BR, and the average value, maximum value, and minimum value were obtained, as shown in Table 6.

[0084]

[Table 6]

From Table 6, it was confirmed that the average value was within 0.01 μm, and the variation (MAX-MIN) was about 0.05 μm, and the finish was extremely accurate.

Further, as a result of producing an STN type color liquid crystal display element as shown in FIG. 3 using the color filter layer 3 produced under these conditions, it is possible to achieve the same characteristics and quality as in Example 1. did it. In addition, by performing the above procedure, it is possible to correct the pinhole defect generated in the R and G hue films 3r and 3g by filling it with the resin material of B, thereby improving the non-defective rate.

In the formation of the R and G hue films 3r and 3g, it is possible to perform back exposure before development by using the same mask as that used for each main exposure.

[Embodiment 3] FIG. 15 shows a flow of manufacturing a color filter layer of an STN type color liquid crystal display device according to a third embodiment of the present invention. FIG. 16 shows the dot shapes of the R, G, and B hue films 3r, 3g, and 3b of the color filter layer 3 manufactured in such a process.

Here, the same substrate, R,
G and B films were prepared, and the color filter layer 3 was formed under the conditions shown in Table 7. The post-exposure conditions were obtained from a basic experiment, as in Example 1. R, G hue film 3r
After the development, 3g was formed, post-exposure was performed by front exposure after development, and main exposure and post-exposure were simultaneously performed only on the B hue film 3b.

[0090]

[Table 7]

The surface of the color filter layer 3 manufactured under these conditions was measured at 6 points with a surface roughness meter in the same manner as in Example 1, and the results are as shown in Table 8.

[0092]

[Table 8]

Then, an overcoat layer 6 is further formed, and its surface is measured with a surface roughness meter at 5 points per substrate and 4 substrates, for a total of 20 points, and based on the height of the R hue film 3r, The data was tabulated as the film thickness difference between GR and BR, and the average value, maximum value, and minimum value were obtained, as shown in Table 9.

[0094]

[Table 9]

From Table 9, it was confirmed that the average value was within 0.01 μm, and the variation (MAX-MIN) was about 0.05 μm, and the finish was extremely accurate. Further, using the color filter layer 3 manufactured under these conditions, an STN-type color liquid crystal display device as shown in FIG. 3 was manufactured. As a result, the same characteristics and quality as in Example 1 could be achieved.

In this case, as in the second embodiment, R,
It is also possible to correct the pinhole defect generated in the G hue films 3r and 3g by filling it with the resin material of B,
The non-defective rate also improved.

Comparative Example 1 For comparison, a color filter layer was prepared under the same conditions as in Example 1 except that post-exposure was not performed. FIG. 17 shows the dot shapes of the R, G, and B hue films 37r, 37g, and 37b of the color filter layer of the comparative example.

Table 10 shows the manufacturing conditions.

[0099]

[Table 10]

The surface of the color filter layer produced under these conditions was measured at 6 points with a surface roughness meter in the same manner as in Example 1, and the results are as shown in Table 11.

[0101]

[Table 11]

Then, an overcoat layer was further formed, and the surface thereof was measured with a surface roughness meter for 5 points to 4 substrates, that is, 20 points in total. Based on the height of the R hue film 37r, G- The data were tabulated as the difference in film thickness between R and BR, and the average, maximum, and minimum values were obtained, as shown in Table 12.

[0103]

[Table 12]

From Table 12, the average value exceeds 0.1 μm.
It was confirmed that the variation (MAX-MIN) was about 0.2 μm, which was worse than that of the color filter layer 3 manufactured using the present invention.

Further, when an STN-type color liquid crystal display device as shown in FIG. 3 was manufactured using the color filter layer manufactured under these conditions and the optical characteristics were confirmed, the contrast was 35: 1. In addition, since the display quality has a large variation in the thickness of the in-plane color filter layer, non-uniform portions such as reddish, greenish, and blueish portions are particularly observed in a halftone display. High-speed response type (cell thickness 5μm or less)
In the case of manufacturing the STN liquid crystal display element of the above, the non-uniform difference in halftone became remarkable.

[0106]

According to the method of manufacturing a color filter according to the first aspect of the present invention, in the step of forming each hue film, the photosensitive material is exposed from the front side before development, and a pattern is drawn on the photosensitive material. The method includes a first exposure step and a second exposure step of exposing the photosensitive material again after development and before baking the photosensitive material.

As a result, it is possible to manufacture a smooth color filter. Therefore, by manufacturing a color filter of a super twisted nematic liquid crystal display element by such a manufacturing method, the cell gap becomes uniform. This has the effect of improving contrast and halftone display quality, and improving display characteristics and display quality.

In the method for manufacturing a color filter according to the second aspect of the present invention, in the step of forming each hue film, the photosensitive material is exposed from the surface side before development, and a first pattern is drawn on the photosensitive material. An exposing step and a second exposing step of exposing the photosensitive material again after baking the photosensitive material after the first exposing step, wherein a hue film other than a hue film formed last is included. In the second exposing step in the manufacturing step, the exposing is performed from the front side or the rear side of the transparent substrate after the development, and only the second exposing step in the final forming step of the hue film is performed from the rear side of the transparent substrate before the developing. Is what you do.

Thus, in addition to the effects described in the first aspect, the pinhole defect occurring in the already formed hue film can be eliminated by forming the last hue film at the same time as the formation of the last hue film. Since it can be corrected with a conductive material, there is an effect that the yield rate can be improved.

According to a third aspect of the present invention, in the method for manufacturing a color filter according to the first or second aspect, the photosensitive material receives more exposure energy in the second exposure step than in the first exposure step. Things.

As a result, it is possible to obtain a smoother color filter than the color filter obtained by the method of claim 1 or 2. As a result, the color filter of the super-twisted nematic type liquid crystal display device can be obtained by such a manufacturing method. By manufacturing, the cell gap becomes more uniform, the contrast and the halftone display quality can be improved, and the display characteristics and the display quality can be further improved.

A color liquid crystal display device according to a fourth aspect of the present invention comprises a color filter produced by the method according to the first or second aspect, and has a super twisted nematic liquid crystal molecule arrangement having a twist angle of 180 ° to 360 °. This is a configuration including a liquid crystal panel.

Since the color filter produced by the method of claim 1 or 2 is very smooth, a super-twisted nematic liquid crystal display device provided with such a color filter can improve the contrast and improve the halftone display quality. Improvements can be achieved, and the display device has very excellent display characteristics and display quality.

[Brief description of the drawings]

FIGS. 1A to 1M are cross-sectional views illustrating a process of manufacturing a color filter layer in a color liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a process chart showing a manufacturing flow of a color filter layer.

FIG. 3 is a sectional view of a color liquid crystal display device.

FIG. 4 is a graph showing a change in film thickness in the order of a color filter layer forming process.

FIG. 5 is a graph showing a comparison of a film thickness change rate in a color filter layer forming step when post-exposure is performed and when post-exposure is not performed.

FIGS. 6A to 6D are explanatory views showing a shape change in a color filter layer forming step of performing post-exposure.

FIGS. 7A and 7B are explanatory diagrams showing the shape of the hue film of the color filter layer after the main bake when over-developing is performed.

FIG. 8 is a graph showing a change in film thickness from completion of development of a color filter layer to completion of baking when post-exposure is not performed.

FIG. 9 is a graph showing the film thickness at the end of the main bake when the post-exposure amount is used as a parameter.

FIG. 10 is a process chart showing a flow of manufacturing a color filter layer of Example 1 which is an example of the present invention.

FIG. 11 is an explanatory diagram showing a shape of a color filter layer of Example 1.

FIG. 12 is an explanatory diagram showing measurement points for measuring the surface of a color filter layer with a surface roughness meter.

FIG. 13 is a process chart showing a manufacturing flow of a color filter layer of Example 2 which is one example of the present invention.

FIG. 14 is an explanatory diagram showing the shape of a color filter layer of Example 2.

FIG. 15 is a process chart showing a manufacturing flow of a color filter layer of Example 3 which is an example of the present invention.

FIG. 16 is an explanatory diagram showing a shape of a color filter layer of Example 3.

FIG. 17 is an explanatory diagram showing a shape of a color filter layer of a comparative example of the present invention.

FIGS. 18A to 18D are cross-sectional views illustrating a process for manufacturing a color filter layer according to a conventional technique.

FIGS. 19A to 19C are explanatory views showing a shape change in a color filter layer forming step according to a conventional technique.

FIG. 20 is a graph showing a relationship between a cell gap and contrast in an STN liquid crystal display device.

FIGS. 21 (a) and (b) are explanatory diagrams showing the relationship between the difference in film thickness of R, G, and B hue films (after overcoat processing) and display quality in an STN type liquid crystal display device.

[Explanation of symbols]

 1, 2 transparent substrate 3 color filter layer (color filter) 3r R hue film 3g G hue film 3b B hue film 13 liquid crystal layer 14r R photosensitive resin material layer (photosensitive material) 14g G photosensitive resin Material layer (photosensitive material) 14b B photosensitive resin material layer (photosensitive material)

Claims (4)

[Claims] In a method of manufacturing a color filter formed using a negative photosensitive material and having at least two color hue films, the step of forming each hue film includes applying the photosensitive material to a surface before development. A first exposure step of exposing from the side and drawing a pattern on the photosensitive material; and a second exposure step of exposing the photosensitive material again after development and before baking the photosensitive material. A method of manufacturing a color filter. 2. A method of manufacturing a color filter having a hue film of at least two colors formed using a negative photosensitive material, comprising: A first exposure step of exposing from the side and drawing a pattern on the photosensitive material, and a second exposure step of exposing the photosensitive material again after the first exposure step and before baking the photosensitive material. Of these, the second exposure step in the step of manufacturing a hue film other than the hue film formed last is performed by exposing from the front side or the back side of the transparent substrate after development, and in the step of manufacturing the hue film finally formed. A method for manufacturing a color filter, comprising exposing only the second exposure step from the back side of a transparent substrate before development. 3. The method according to claim 1, wherein the second exposure step is performed more than the first exposure step.
3. The method according to claim 1, wherein the photosensitive material receives a large amount of exposure energy. 4. A color filter produced by the production method according to claim 1 or 2, wherein a twist angle is 180 ° or more.
A color liquid crystal display device comprising a liquid crystal panel having a 360 ° super twisted nematic liquid crystal molecular arrangement.