JPH0462517A - Color liquid crystal display device - Google Patents

Abstract

PURPOSE:To easily laminate a transparent electrode and to increase the reliability of the electrode by forming a smoothing film of plural layers of synthetic resin differing in molecular weight and improving the smoothness of the surface of a color filter. CONSTITUTION:Synthetic resin with low molecular weight is soft and can easily and uniformly fill gaps between picture elements, but synthetic resin with high molecular weight is hard and hardly fill the small gaps uniformly, so when the smoothing film 12 which has, for example, <=20,000 molecular weight is used, its resin easily enter the gaps of picture elements 6, 8, and 10 to nearly smooth the surface. Then the irregularity which is not removed with the is smoothed with the smoothing film 14 having the low molecular weight is smoothed with a smoothing film 14 having, for example, >=20,000 high molecular weight and serves as a hard surface film on the surface of the color filter, so the transparent electrode can easily be laminated and its reliability becomes higher Further, the surface of the color filter is smoothed, then the thickness of a liquid crystal layer comes uniform, so that the display quality is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a color liquid crystal display device, and more particularly to smoothing the surface of a color filter used in a liquid crystal display device.

[Prior Art] Color filters used in color liquid crystal display devices are manufactured by dyeing method (Japanese Unexamined Patent Publication No. 60-55,301), pigment dispersion method (Unexamined Japanese Patent Publication No. 1-152,449, No. 2-47゜605), It is manufactured by a printing method (Japanese Unexamined Patent Publication No. 60-98,482). In all of these manufacturing methods, gaps remain between pixels, and the surface of the color filter does not become smooth.

If the surface of the color filter is not smooth, it will be difficult to form a transparent electrode such as an ITO film to cover the filter.
Problems such as disconnection of the transparent electrode may occur.

In order to obtain a color filter with a smooth surface, it is known to provide a smoothing film of synthetic resin on the surface of the pixel (Japanese Patent Laid-Open No. 61-624). In this technology, the synthetic resin in the smoothing film fills the gaps between pixels to smooth the color filter.

However, since the gaps between pixels are thin and deep, it is difficult to completely smooth the color filter with a smoothing film made of synthetic resin. In this case, corresponding unevenness remains between pixels on the surface of the color filter. Therefore, it is necessary to further improve the technology for smoothing the color filter surface.

[Problem to be solved by the invention] The problem to be solved by the invention is to solve the problem of color filters of liquid crystal display devices.
The objective is to improve the smoothness of the surface as well as the hardness of the surface. By making the surface of the color filter smooth and increasing its hardness, it becomes easier to stack transparent electrodes, and its reliability is high.

Furthermore, when the surfaces of the color filters are made smooth and even, the thickness of the liquid crystal layer becomes uniform, and the display quality is also improved.

[Configuration 1 of the Invention The color liquid crystal display device of the present invention includes a liquid crystal layer interposed between opposing light-transmitting substrates, a pixel region formed by a color filter on one substrate, and a smoothed pixel region. In a color liquid crystal display device coated with a film, the smoothing film is formed of a plurality of layers made of synthetic resins with different molecular weights, and the smoothing film on the side closer to the pixel area is made of a low molecular weight synthetic resin, It is characterized in that the smoothing film on the side far from the area is made of a high molecular weight synthetic resin.

In general, low molecular weight synthetic resins are soft and can easily fill the spaces between pixels uniformly. High molecular weight synthetic resins are hard and difficult to uniformly fill small gaps. Therefore, the gaps between pixels are filled with a low-molecular-weight synthetic resin, and the remaining unevenness is smoothed with a high-molecular-weight synthetic resin. The high molecular weight smoothing film on the surface of the color filter becomes a hard surface film and improves the hardness of the color filter surface.

The smoothing film may be a two-layer film of a low molecular weight film and a high molecular weight film, but may also be a three-layer film, a four-layer film, or the like. In this case, the molecular weight of the smoothing film is increased sequentially from the side closer to the pixel to the side farther from the pixel. Of course, the molecular weight of the smoothing film may be increased continuously from the side closer to the pixel to the side farther away from the pixel.

The molecular weight of the smoothing film is, for example, less than 20,000 on the side near the pixels;
More preferably, the value is 10,000 or less, and the value on the side farthest from the pixels is 20,000 or more, and is selected depending on the width between pixels, the depth, etc.

The narrower and deeper the gap between pixels, the smaller the molecular weight of the low molecular weight smoothing film, and the smaller the unevenness on the surface of the low molecular weight smoothing film. The molecular weight of the high molecular weight smoothing film is determined depending on the degree of unevenness remaining in the low molecular weight smoothing film and the required surface hardness.

The material for the smoothing film is, for example, a highly transparent acrylic resin, and in addition to this, polyimide resins, epoxy resins, urethane resins, etc., which have high heat resistance but are colored, may also be used. It is preferable that the type of synthetic resin used be the same on both the side near and far from the pixel in order to improve mutual compatibility between the resins and facilitate manufacturing. Further, the smoothing film may be manufactured by using, for example, a roll coater or transfer from a film with low adhesion to the resin.

[Example 1 An example is shown in FIG. 1. In the figure, -C, 2 is a transparent substrate such as glass, and 4 is a black matrix made of a metal film such as Cr, which may not be provided. 6°8.10 is a pixel,
For example, pixel 6 represents red, pixel 8 represents green, and pixel IO represents blue. These pixels 6゜8, 1O are dyeing method, pigment dispersion method,
Alternatively, it can be manufactured using a printing method or the like. Here, since the pixels cannot be manufactured so as to be in perfect contact with each other, gaps are created between the pixels.

12 is a low molecular weight smoothing film, for example, the molecular weight is less than 20,000, more preferably 10,000 or less. The smoothing film 12 includes
For example, acrylic resin is used. The type of resin is not limited to acrylic, and polyimide resin, epoxy resin, urethane resin, etc. can also be used. The low molecular weight smoothing film 12 has a low molecular weight of the synthetic resin and has low viscosity when formed.
It easily penetrates into the gaps between 0 and 0 and makes the surface generally smooth.

14 is a high molecular weight smoothing film, and a low molecular weight smoothing film 12
Synthetic resins of the same type are preferred. High molecular weight smoothing film 4
The molecular weight is, for example, 20,000 or more. The high molecular weight smoothing film 14 smoothes the unevenness left by the low molecular weight smoothing film 12 and becomes a hard surface film on the surface of the color filter.

The smoothing film 12.14 may be applied using, for example, a roll coater. Alternatively, a synthetic resin that will be the material for the smoothing film 12.14 is applied to a Teflon film, etc., and this film is pressed onto the pixels 6.8.10, and the synthetic resin is applied evenly to the gap between the pixels 6, 8.10. All you have to do is transfer it so that it fills in the area, and then peel off the Teflon or other film.

The smoothing films 12 and 14 are preferably formed one layer at a time.

16 is a transparent electrode such as a TTO film (In-3n oxide film) laminated on the high molecular weight smoothing film 14, and 18 is a liquid crystal layer. The liquid crystal layer on the opposite side of the transparent electrode 16 has another transparent electrode (not shown) and its substrate, and the thickness of the liquid crystal layer 18 is regulated by a spacer (not shown) or the like. Further, there is a backlight light source (not shown) on the back surface of the glass substrate 2, and light from the light source passes through the color filter and the liquid crystal layer 18, and exits to the outside via the glass substrate on the opposite side.

The second factor is an enlarged view of the embodiment. The thickness of the pixels 6 and 810 is, for example, about several micrometers, and the gaps between the pixels are deep, so it is difficult to completely smooth the pixels using only the low molecular weight smoothing film 12. The remaining unevenness is then smoothed with a high molecular weight smoothing film 14. The high molecular weight smoothing film 14 is
High hardness due to the use of synthetic resin with a large molecular weight. Therefore, a hard smoothing film 14 remains on the surface of the color filter. Smoothing film 12. ．． 14 are collectively referred to as a smoothing film 15.

FIG. 3 shows a conventional color liquid crystal display device.

In this color liquid crystal display device, since the smoothing film 01 is composed of one layer, it is difficult to satisfy two requirements of surface hardness and smoothness at the same time. In addition, in the case of one layer, the surface of the smoothing film O1 has significant unevenness.

Table 1 shows the smoothness of the color filter surface when acrylic resin is used for the smoothing films 12 and 14.01. The average molecular weight of the low molecular weight smoothing film 12 is about 8000,
The average molecular weight of the high molecular weight smoothing film 14 is approximately 25,000.
The average molecular weight of the smoothing film 01 of the comparative example is about 12.000.
And so. The thickness of the smoothing film 12.01 is for pixels 6 and 8.1.
The film thickness of the smoothing film 14 is approximately 1 μm at the top of 0.0 and is approximately 0.3 μm.
It is m. As is clear from Table 1, the unevenness on the surface of the color filter in the example is reduced to about 1/3 to 115 of that of the conventional example.

Thickness of the first surface element (μm) Smoothness (μm) 4! Yo! Example 2.0 ±0.1 ±0.1 Comparative example 2.0 ±0.1 ±0.3~
0.512 Low molecular weight smoothing film, 14 High molecular weight smoothing film.

[Effects of the Invention] In the color liquid crystal display device of the present invention, the smoothness of the color filter surface is improved and the hardness of the surface is improved. As a result, transparent electrodes can be easily laminated, and highly reliable electrodes can be obtained. Next, by making the average height of the color filter surface the same, the thickness of the liquid crystal layer can be made uniform and display quality can be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the embodiment, and FIG. 2 is an enlarged sectional view of the main part thereof. FIG. 3 is a sectional view of a conventional example. In the figure, 2 substrates, 6.8.10 pixels, Figure Figure Figure Figure

Claims (1)

[Claims] (1) In a color liquid crystal display device in which a liquid crystal layer is interposed between opposing light-transmitting substrates, a pixel region formed by a color filter is provided on one substrate, and the pixel region is covered with a smoothing film, as described above. The smoothing film is formed of multiple layers made of synthetic resins with different molecular weights, and the smoothing film on the side closer to the pixel area is made of a low molecular weight synthetic resin, and the smoothing film on the side far from the pixel area is made of a high molecular weight synthetic resin. A color liquid crystal display device characterized by being constructed from synthetic resin.