JPH02217823A - Production of liquid crystal display device - Google Patents

Abstract

PURPOSE:To produce color filters having smooth surfaces by forming the color part to be finally formed so as to cover the other color parts to fill the grooves between the color parts. CONSTITUTION:Coating compds. of red R and blue B formed by dispersing pigments into an alkyd resin so as to obtain desired spectral characteristics are printed and formed successively at 3 micron film thickness by a printing method on the surface of a light transmittable substrate 1 consisting of, for example, glass. First apertures 3a and second apertures 3b are successively formed at this time and the coating compd. of green G formed by dispersing the pigment in a urethane acrylate resin so as to obtain desired spectral characteristics is applied by spin coating as the final color part so as to cover the top of the color parts 2a and the color parts 2c to form the color parts 2b. There parts are polished after baking, by which the color filters 11 are formed. The color parts 2a to 2c of the red R, green G and blue B are formed by two times of printing stages in such a manner and the color filters 11 having good surface characteristics are simultaneously obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a method of manufacturing a liquid crystal display device, and particularly to a method of manufacturing a color filter for a liquid crystal display device.

(Prior Art) In recent years, liquid crystal display devices have come to be used in various fields by taking advantage of their advantages such as low weight and low power consumption. There has been a particularly strong demand for color liquid crystal display devices.

However, conventional color filters for liquid crystal display devices are red (
All the color parts of R), green (G), and blue (B), as well as the black matrix for increasing contrast, were manufactured using a photolithography process. For this reason, a large number of complicated processes are required, and the cost is also high.

Therefore, it has been considered to produce red (R), green (G), blue (B) color areas, or a black matrix by a printing method.

For example, Japanese Patent Application Laid-Open No. 81-312 discloses methods for producing color filters for liquid crystal display devices using the printing method.
2. Description of the Related Art A method for manufacturing a liquid crystal color display element described in Publication No. 2 is disclosed and known.

This process consists of printing opaque areas on a substrate at predetermined intervals, printing color filters between the opaque areas, and flattening the color filters. This method eliminates the need for a graphic process, making it possible to manufacture color filters efficiently and at low cost.

(Problems to be Solved by the Invention) However, when the colored parts are sequentially printed as described above, grooves are formed between each colored part. For this reason, even if the surface of the colored parts is polished, it is difficult to remove the grooves formed between each colored part.
It could not be done on a flat surface.

In addition, Japanese Patent Application Laid-Open No. 61-3123 discloses that after forming opaque parts at predetermined intervals, colored parts are formed between each opaque part, transparent parts or opaque parts are again formed between each colored part, and the color filter is polished. It is disclosed that the color filter can be manufactured in this way, and the surface smoothness of the color filter can be made good.

However, even if it is easy to manufacture by the printing method in this way, multiple printing steps reduce productivity and increase costs.

SUMMARY OF THE INVENTION The purpose of the present invention was to provide a liquid crystal display device that can be easily manufactured at low cost and that can provide good images without alignment defects. shall be.

[Structure of the Invention] (Means for Solving the Problems) A method for manufacturing a liquid crystal display device according to the present invention is a method for manufacturing a liquid crystal display device including a color filter in which colored portions are sequentially formed on a transparent substrate. A step of sequentially forming colored portions on a light-transmitting substrate, a step of forming a final colored portion on the light-transmitting substrate such that the final colored portion covers the colored portion, and a final color portion The method is characterized by comprising a step of polishing and exposing the colored portion.

Further, in the method for manufacturing a liquid crystal display device described above, the polishing operation can be facilitated by forming the film on the end portion of the light-transmitting substrate to be thicker than the other portions and polishing the film.

(Function) As described above, by forming the finally formed colored portions so as to cover other colored portions, the gaps between the colored portions can be filled. A color filter with a smooth surface can be manufactured by polishing in such a state so that all colored parts are sufficiently exposed.

At this time, it is preferable to use a resin with high polishing resistance for the colored portion to be finally formed. Polishing resistance in this specification is different from the commonly used Brinell hardness, etc., and is determined by the time it takes to polish a predetermined amount. Taking this into consideration, epoxy or urethane resins are preferably used as the resins for the colored portions that are finally formed.

Polishing can be broadly classified into lapping and borizing, but borizing is preferable in view of the controllability of polishing as color filters become larger. This is because when attempting to polish a large-area color filter by lapping, it becomes extremely difficult to uniformly control the polishing amount of each part of the color filter.

Furthermore, when attempting to polish a large-area color filter, the polishing speed at its edges becomes faster than at other parts.

For this reason, by forming the colored portions installed at the ends of the color filter to be thicker than the other colored portions, even the ends of the color filter can be polished uniformly. Furthermore, although the manufacturing process is increased, a material with high polishing resistance may be provided only at the end portion of the color filter as a polishing-resistant protection portion.

By manufacturing color filters in this way,
Since the electrodes or the alignment film can be properly installed on the surface of the color filter, it is possible to obtain a liquid crystal display device that can provide a good image without display unevenness.

Hereinafter, a method for manufacturing this liquid crystal display device will be specifically described.

(First Example) A method for manufacturing a liquid crystal display device according to a first example of the present invention will be described in detail with reference to FIG.

As shown in FIG. 1(a), red (R) and blue are formed by dispersing pigments in an alkyd resin on the surface of a light-transmitting substrate (1) made of, for example, glass so as to obtain desired spectral characteristics. The coating material (B) was printed and formed in a film thickness of 3 microns by a sequential printing method. At this time, there is a green (G) color area (2b) between the red (R) color area (2a) and the blue (B) color area (2C).
A first opening (3a) that is large enough to form a second opening (3a) and a second opening (gb) that is only a few microns in size are sequentially formed. Further, the film thickness of this colored portion varies depending on the pigment content (although it is preferably about 2 to 5 microns in consideration of polishing in a subsequent process).

Next, as shown in FIG. 1(b), a green (G) paint made of urethane acrylate resin with pigment dispersed therein so as to obtain the desired spectral characteristics is used as the final color part.
A) and the colored portion (2C) are coated using a spin cord to form the colored portion (2b).

After baking the colored part (2b) at 180°C for 30 minutes in such a state, it was heated to 10g/g as shown in Figure 1(C).
Boris for 5 minutes with a load of c- and color filter (11
) to form. Ceria (CeO) powder (manufactured by Mitsui Kinzoku Co., Ltd. with a particle size of 0.8 to 1.5 microns) was used as the abrasive material for this boring. The polishing conditions include the smoothness of the surface or the colored part (2a).

Considering polishing that fully exposes (2c), 5 to 10
Polishing for about 3 to 5 minutes at about g/c- is preferable.

Although it may be used as a color filter (11) in this state, considering the durability of the color filter (11) or the smoothness of the surface of the color filter (11),
As shown in FIG. 1(d), the overcoat layer (15) may be formed with a thickness of 1.0 micron.

Various materials can be considered for this overcoat layer (15), but considering the wettability with the colored parts (2a), (2b), and (2c), acrylic resin is suitable, and the film thickness is may be about 1.0 to 3.0 microns.

As described above, the red (R), green (G), and blue (B) color parts (2a) and (2b) are formed by two printing steps.

(2c) can be formed, and at the same time, a color filter (11) with good surface properties can be obtained.

After manufacturing the color filter (11) in this manner, if a simple matrix type liquid crystal display device is to be manufactured, for example, 1. T.O.

A striped transparent conductive film made of (Indium Tin Oxide) is formed as a first electrode. Then, an alignment film is formed on this first electrode, rubbed in one direction, and a polarizing plate is installed on the opposite side of the light-transmitting substrate (1) at an angle where the rubbing direction and the polarization axis match, and a liquid crystal display device is formed. A first substrate is formed.

In addition, 1. T, 0. A striped transparent conductive film is formed by sputtering as the second electrode, and a paint containing carbon black dispersed in alkyd resin is printed between the striped second electrodes for the purpose of improving display contrast. The black stripes are formed into a matrix shape. Furthermore, an alignment film is formed on this second electrode and rubbed in one direction.

Then, polarizing plates are installed on many sides of the light-transmissive substrate at an angle where the rubbing direction and the polarization axis coincide to form a second substrate of a liquid crystal display device.

The substrates were aligned so that the electrodes of the first substrate and the second substrate were perpendicular to each other, and a nematic liquid crystal composition was injected and sealed to obtain a liquid crystal display device.

In the liquid crystal display device manufactured in this way, the first electrode is installed on the color filter (11) which is formed very smoothly, so it is assumed that the installation condition of the first electrode is good. Become. Furthermore, since the smooth alignment film is subjected to the rubbing treatment, there are no areas that are shadowed by convex portions and are not subjected to the rubbing treatment.

When a video signal from a video signal generating means is applied to the first electrode and second electrode of such a liquid crystal display device to drive the television, good alignment of the liquid crystal molecules can be obtained, resulting in highly accurate display characteristics. The liquid crystal display device shown in FIG.

Here, a simple matrix type liquid crystal display device is used as an example to drive a television, but an active matrix type liquid crystal display device may also be used, and can be used in various fields such as in-vehicle use or as a personal word processor display.

Furthermore, since the color filter (11) is manufactured by two printing steps and one polishing step, the manufacturing process is extremely simplified and mass production can be performed at low cost. Therefore, the cost of the entire liquid crystal display device can be kept sufficiently low.

(Second Example) A method of manufacturing a liquid crystal display device according to a second example of the present invention will be described in detail with reference to FIG.

As shown in FIG. 2(a), red (R) is made by dispersing a pigment in an alkyd resin on the surface of a light-transmitting substrate (1) made of, for example, glass so as to obtain desired spectral characteristics.
Green (G) and blue (B) paints are sequentially printed at predetermined intervals using the Mark II method. Colored parts (2a), (2b), and (2c) are then formed by baking each paint.

Next, as the final color part, a black base material (
5) is applied using a spin cord. Then, the black base material (5) is sufficiently baked so that polishing can be easily controlled in a subsequent process. The black base material (5) used here was one in which carbon black was dispersed in urethane acrylate in consideration of polishing resistance. The content of this carbon black is sufficient as long as it achieves a certain light-shielding effect.
Polishing control can be facilitated by reducing the content as much as possible and improving polishing resistance.

In addition, as shown in FIG. 2(b), in consideration of the uniformity of polishing in the post-process, the light-transmitting substrate (
Thick parts (7) were formed on each end (1a) of 1) by making the black base material (5) thicker than other parts.

By forming such thick portions (7) on each end (la) of the light-transmitting substrate (1), the light-transmitting substrate (1) will remain intact even if it is polished in a later process. Each end (la) can also be made flat with a similar film thickness. Here, the thick part (
7), a resin or the like having high polishing resistance may be placed on each end (1a) of this light-transmitting substrate (1). In addition, the thick part (7) is connected to the light-transmitting substrate (1).
), the entire light-transmissive substrate (1) can be uniformly flattened and material loss at the ends (1a) can be eliminated.

In this state, as shown in FIG. 2(C), the colored part (2
The surface of the black base material (5) is polished so that a), (2b), and (2c) are exposed respectively, and the black matrix (
9) was formed to obtain a color filter (11). The polishing conditions here were polishing at approximately 30 g/c for 5 minutes.

As described above, by forming the black base material (5) at each end of the light-transmitting substrate (1) to be thicker than other parts, each end of the light-transmitting substrate (1) can be polished at a faster polishing speed. The portion is also polished to 1illF to the same extent as the other portions, resulting in uniform light transmittance.

Although it is possible to use it as a color filter (11) even in this state, in consideration of durability etc.
An overcoat layer (15) may be formed as shown in d). Here, the materials used for the overcoat layer (15) include each color portion (2a).

(2b) and (2c) acrylic resins that exhibit good wettability are suitable. Overcoat layer (15) at this time
The film thickness of about 1.0 to 3.0 microns can smooth fine surface roughness and improve durability.

In this state, I, T, O, are connected to color filters (
A layer of 200 angstroms thick is placed on the surface of the overcoat layer (J5) in step 11) by sputtering.

Then, an alignment film is formed on this transparent electrode, and a polarizing plate is further provided on the other surface of the light-transmitting substrate (1), thereby forming a first electrode substrate of a liquid crystal display device.

In addition, by forming an alignment film on the electrode formed in a matrix with thin film transistors on the surface of the other light-transmitting substrate, and further installing a polarizing plate on the other surface of the light-transmitting substrate (1), A second electrode substrate of a liquid crystal display device is formed.

By sandwiching the nematic liquid crystal composition between the first electrode substrate and the second electrode substrate in this manner, a liquid crystal display device can be obtained.

Since the liquid crystal display device manufactured in this way is formed of the first electrode substrate having the color filter (11) with good surface properties, transparent electrodes or alignment films can naturally be installed well, and the crystal A vivid image can be obtained.

Also, depending on the printing method, each color part (2a), (2b),
(2c) can be formed, so the color filter (11) can be manufactured inexpensively and efficiently without a complicated photolithography process unlike the conventional method. Furthermore, in the production of the black matrix (9), Subinko-1
It is also possible to reduce the number of printing steps. Although the black base material (5) is formed using a spin cord here, it is not limited to this and may be installed using a roller or the like.

Even in a liquid crystal display device constructed in this way, a color filter (1
1) can be formed. Therefore, the liquid crystal display device can also display high-definition images favorably.

Although a light-transmissive active matrix liquid crystal display device having thin film transistors is shown as an example of the liquid crystal display device here, the present invention is not limited to this.
It may be a reflective type liquid crystal display device or a simple matrix type liquid crystal display device.

[Effects of the Invention] As described in detail above, in the method for manufacturing a liquid crystal display device of the present invention, it is possible to produce a liquid crystal display device that can obtain a good image without alignment defects with an inexpensive and easy manufacturing process. can.

[Brief explanation of the drawing]

Figure m1 is a schematic process diagram showing a method for manufacturing a liquid crystal display device according to one embodiment of the method for manufacturing a liquid crystal display device of the present invention, and FIG. 2 is a schematic process diagram showing another example of the method for manufacturing a liquid crystal display device of the present invention. 1 is a schematic process diagram showing a method for manufacturing a liquid crystal display device. (1)...Light transmitting substrate (2)...Color part (5)...Black base material (9)...Black matrix (11)...Color filter (15)...Over coat layer

Claims (2)

[Claims] (1) A method for manufacturing a liquid crystal display device equipped with a color filter formed by forming a plurality of colored portions on a light-transmitting substrate, including the step of sequentially forming a plurality of colored portions on the light-transmitting substrate; A liquid crystal display device comprising the steps of forming a final color portion on a light-transmitting substrate so as to cover the color portion, and polishing the final color portion to expose the color portion. Production method. (2) In the method of manufacturing a liquid crystal display device according to claim 1, the liquid crystal display is characterized in that the film thickness on the end portion of the light-transmitting substrate is formed thicker than the film thickness on other parts and then polished. Method of manufacturing the device.