JPS5846326A - Cell structure of color liquid crystal display device - Google Patents

Abstract

PURPOSE:To prevent the degradation in oriented layers on account of moisture and to improve the reliability of a color liquid crystal display device contg. color filters in its cell in said device by constituting the liquid crystal orienting layers of polyimide high polymer films. CONSTITUTION:Signal side electrodes Y11, Y12, Y13, Y21, Y22, Y23...Yn1, Yn2, Yn3 are provided on a signal-side substrate 2. A red filter 9 is provided on the Y11, Y21,...Yn1, a green filter 10 on the Y12, Y22...Yn2 and a blue filter 11 on the Y13, Y23,...Yn3. Films of polyimide high polymers (e.g.; ''PiX-#5400 '' produced by Hitachi Chemical Co., Ltd.) are provided thereon and the films are rubbed, whereby an oriented layer 8 is formed. On the other hand, scanning side electrodes X1, X2...Xm are provided on a scanning side substrate 1, and an oriented layer 8 is formed thereon. Thereafter, the substrate 2 and the substrate 1 are superposed in such a way that both electrodes are intersected orthogonally with each other, and a liquid crystal 7 is sealed therebetween, whereby a color liquid crystal display device consisting of red picture elements 4, green picture elements 5 and blue picture elements 6 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a color liquid crystal display device in which a color fill is provided inside a liquid crystal cell.

For color display in conventional liquid crystal display devices, DA
A method that utilizes the birefringence of liquid crystal molecules, which is called the P method.
Twisted nematic systems in which a color polarizer is used as one of the polarizers, color fills added to the neutral polarizer, and guest-host systems in which dichroic dyes are added to the liquid crystal layer. has been proposed. Here, the DAP method that utilizes the birefringence of the liquid crystal molecules can reproduce various colors by controlling the tilt of the liquid crystal molecules by applying an electric field and by interfering with light passing through the liquid crystal cell. However, on the other hand, there are practical problems in that sophisticated technology is required to control the cell thickness of the liquid crystal cell, and the displayed color has a viewing angle dependence that differs depending on the current position. On the other hand, in systems that use color polarizers or color fills, it is a common problem that the displayed colors are affected by changes in the cell thickness of the liquid crystal cell.
In addition, viewing angle dependence is considerably reduced compared to the DAP method described above, making it possible to easily perform multicolor display with a single cell, and eliminating display color variations due to parallax.

Similarly, the guest-host method has fewer problems with cell thickness and viewing angle dependence. However, in a color liquid crystal display device with a structure in which a conventional color filter is installed inside the liquid crystal cell,
Polyvinyl alcohol is used for the alignment plate provided on the color filter to orient liquid crystal molecules, and since polyvinyl alcohol is soluble in water, it is difficult to remove it from the outside into the liquid crystal cell during long-term use. There is a problem in that when moisture enters the liquid crystal, the orientation 1 of the polyvinyl alcohol changes in quality, and as a result, the alignment force for liquid crystal molecules deteriorates.

In view of the above problems, the present invention combines a twisted nematic method, a guest host method, etc. with a color filter, and utilizes a color filter internally contained within a liquid crystal cell (in a liquid crystal display device that displays multiple colors with a minus sign). To provide a new and useful cell structure of a color liquid crystal display device, which uses a polyimide polymer film for aligning liquid crystal molecules formed on a color filter, and prevents deterioration of alignment force due to moisture intrusion. The purpose is to

Hereinafter, the present invention will be explained in detail according to embodiments with reference to the drawings.

FIG. 1 is a plan view of a color liquid crystal display device showing one embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG.

This embodiment uses a transmission type twisted nematic type matrix electric *t? A three-color liquid crystal cell with BM is used. The scanning side substrate 1 has scanning side electrodes (X electrodes) X t , X 21 . . . , Xm made of transparent conductive electrodes.

On the other signal side substrate 2, signal side electrodes (Y electrodes) Y1□* Y12+ YI3+ Y2 are similarly made of transparent conductive material.
1+Y22* ”'+ Ynl* Yn2+ Yn3
(m and n are multiples of 3) are formed into a band shape by a photoetching method or the like. The width of the X electrode is more than three times wider than the width of the Y electrode. Even though the X electrodes and Y electrodes are arranged in directions that intersect with each other to form a matrix, display pixels are formed in the areas where the X and Y electrodes intersect, and in these pixels (X, Y), 1st line pixel (XI
-Ytt), (Xi, Y21)..., (X
mth line pixel (X m * Y
I 3 ), (X me Y z3) + ...+
A red filter 9 is placed on the Y electrode corresponding to (X m + Yn3), and a red filter 9 is placed on the Y electrode corresponding to (X m + Yn3).
YI2), (Xll Y22),...

(Xll Yn2) mth line pixel (X m
+y,,).

(Xme Y2+ )+ ・”* (Xme Ynl
), a green filter 10 is attached to the Y electrode 5, and a green filter 10 is attached to the Y electrode 5 corresponding to the
Line pixel (Xll YI3) I (Xll Y
23),...

The mth line pixel (Xm, Yn3) from (XI, Yn3)
12).

Blue filters 11 are layered on the Y electrodes corresponding to (Xme Y22L...+ (Xm, Yn2), respectively.

The various color fills 9, 10, and 11 mentioned above are formed as described below. In other words, it is the first transparent color ink.
NAZ-DAR screen process ink 90 shown in the table
00 series (manufactured by Nasda Company International, satin gloss ink) and printed at a predetermined position on the Y electrode. However, the present invention is not limited to these color inks.

Table 1 In this example, three color inks, C0LOR #9083 (red), #9087 (green), and 19086 (blue), from Table 1 are used, and these color inks are printed using a screen printing method. Printing is performed on a predetermined pixel area on the electrode surface.

Thereafter, the printed color ink is baked and fixed by heat treatment at about 300° C. for 2 hours in an open space. As described above, red, green, and blue color filters 9, 10, and 11 are formed on the Y electrode surface, so that the two pixels 4 are colored red, the pixel 5 is colored green, and the pixel 6 is colored blue.

On the color fill 9.10.11, a polyimide polymer film (product name: P
iX#5400, manufactured by Hitachi Chemical Co., Ltd.) are superimposed. In addition to the above, other polyimide polymer films include PiB and PiQ.
, KJR (all manufactured by Hitachi Chemical), Torayneece, 5P-710, 5P-X
11 (all manufactured by Toshisha) etc. are applicable. Orientation @8
Since it is necessary to apply the coating thinly and uniformly, N-methylpyrrolidone, a fluorosurfactant FC-431 (manufactured by Sumitomo 3M), etc. are added as a solvent, and the coating is applied using a spinner method.

In addition to the spinner method, a roller transfer method is also possible. After applying the polyimide polymer film, preheat it at 60°C for 5 minutes in an open room, then dry it at 150°C and 20°C for 1 hour, and then heat it to about 300°C.
The alignment film 8 is obtained by heating and baking the film for 30 minutes and rubbing the surface in contact with the liquid crystal with a polishing cloth. Note that this alignment film 8 is provided not only on the signal side substrate 2 but also on the side of the scanning side substrate 1 opposite to the liquid crystal. The polyimide polymer film is not affected by moisture, so the alignment force of orientation@8 is not deteriorated even if moisture enters the liquid crystal cell. Note that the polyimide polymer film may be formed only on the color filters 9, 10, 11, and an alignment film made of other inorganic material may be formed on the other scanning side substrate 1.

The scanning side board 1 and the signal side board 2 are made of epoxy resin NX024.
After a sealing material 3 (manufactured by Sumitomo 3M) is attached to the end portion, it is heated in an open space, and the sealing material 3 is cured to be bonded to each other. Further, a liquid crystal 7 is sealed inside thereof by a vacuum injection method or the like.

As described above, a color liquid crystal cell is constructed which performs colored display by color filling based on the alignment deformation of liquid crystal molecules, and by applying an electric field to the liquid crystal 7 from the power source 13 via the XY electrodes, the light source 14 connects the polarizing plate 12 and the liquid crystal. The light transmitted through the cell gives the observer 15 the red, green, and
A color liquid crystal display device that is observed as a blue colored pattern is obtained. When an electric field is applied to the liquid crystal 7, when the polarizing plate 12 is placed in the parallel position indicated by p, , P2, the liquid crystal 7 having a twisted nematic structure operates as an optical shutter, and for example, as a Y electrode, Yll+ Y21 m...・,X
When an electric field is applied to each line of Xl as an electrode, only the light that has passed through the red filter 9 reaches the observer 15 and is displayed as a red dot on a black background. By appropriately selecting each line of the XY electric electrodes and applying an electric field, a display color corresponding to the selected pixel is displayed arbitrarily.

FIG. 3 is a sectional view of a color liquid crystal display device showing another embodiment of the present invention.

This embodiment uses a three-color liquid crystal cell having a transparent guest-host matrix electrode structure, and employs a White Taylor type guest-host system. In the figure, the same reference numerals as the previous one indicate the same contents. The various red, green, and blue color fills 9, 10, 11 formed on the Y electrode are obtained by printing and baking transparent color inks in the same manner as in the embodiment shown in FIG. Further, an alignment film 8 made of a polyimide polymer film is formed on the side substrate 1.2 in contact with the liquid crystal 7, so that the liquid crystal molecules are horizontally aligned. The liquid crystal 7 injected and sealed into the liquid crystal cell is a dichroic dye-containing liquid crystal obtained by mixing cholesderic liquid crystal as a host and three types of mixed dyes 1116 of cyan, magenta, and yellow as guests.

When there is no electric field, the light absorption by the dye 16 is at its maximum, resulting in an entirely black display. When an electric field is applied, the liquid crystal molecules and dye 16 of that pixel stand up vertically, and light absorption by the dye is almost eliminated. Therefore.

Color filter 9゜10 installed at the bottom of the liquid crystal 7
．． Eleven colors are observed. By appropriately selecting the XY electric field F@ and applying an electric field, display colors corresponding to the pixels can be arbitrarily generated by combining the pixels, as in the embodiment of FIG.

FIG. 4 is a sectional view of a color liquid crystal display device showing a further embodiment of the candy of the present invention.

This embodiment uses a transparent guest-host type matrix computer.
A three-color liquid crystal cell having an @ structure is used, and a Heilmeier type guest-host system is adopted. The same reference numerals as in the previous figure indicate the same contents. Various red, green, and blue color filters 9, 10, 11 are formed in the same way as in Section 2 of "Y Electrode Panel", and these color filters 9, 10. An alignment plate 8 is formed on the II and X electrodes in the same manner as in the above embodiment. The liquid crystal 7 in the liquid crystal cell has a nematic liquid crystal as a host and cyan as a guest.
2 mixed with 16 mixed dyes of magenta and yellow
A liquid crystal containing a colored dye is used.

When there is no electric field, the liquid crystal molecules assume a horizontal alignment, and accordingly, the dye 16 also has maximum light absorption and is shown as a black surface. When an electric field is applied, the liquid crystal molecules and dye of that pixel rise vertically, and as a result, the colors of the color filters 9, 10, and 11 of the liquid crystal 7 are ffQffilled.

In the above embodiment, one color filter is placed on the X electrode.
It is possible to apply the unreleased +1 even if the function is used, and it is not limited to a transmissive liquid crystal cell, but can also be applied to a reflective liquid crystal cell. The display type of the liquid crystal cell is XY Ma)
Not only the IJx display method but also the segment type display method can be used in the same manner, and the display colors can be selected from two or four or more Type 4 hues. For example, a display device that displays bar graphs in two or more colors can be easily manufactured.

According to the present invention, a highly reliable color liquid crystal display device can be constructed, and a display device that operates stably even during long-term use can be obtained. The liquid crystal cell lv of the present invention was heated to 60°C and 9°C.
As a result of measurement in a high temperature and high humidity test at 0°C, no deterioration in orientation was observed even after 10 days or more had passed. On the other hand, when a polyvinyl alcohol film is used for alignment, the result of a test under the same conditions was /1+11, and alignment deterioration of the liquid crystal was observed within a few days.

As described above, the present invention establishes high-quality color display without clouding of display colors due to parallax by interposing a color filter inside a liquid crystal cell.1. This technology improves reliability by preventing the deterioration of the self-aligning blade due to moisture due to the force and orientation, and its technological advantages are remarkable when used as measurement and display equipment for automobiles.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a color liquid crystal display device showing one embodiment of the present invention. FIG. 2 is a sectional view taken along the line AA in FIG. 1. Part 31 is a sectional view of a color liquid crystal display device showing another embodiment of the present invention. FIG. 4 is a sectional view of a color liquid crystal display device showing still another embodiment of the present invention. 1...Scanning side board, 2...Signal side common board, 4,5
゜6...Pixel, 7...Liquid crystal, 8...Orientation-
19...Red filter, 10...Green filter, 11...Blue filter, 16...Dye.

Claims (1)

[Claims] 1. In a color liquid crystal display device in which a translucent color filter is installed inside a liquid crystal cell, a translucent filter for orienting liquid crystal molecules, which is commonly used for aligning liquid crystal molecules, is placed on the color filter in contact with the liquid crystal using a polyimide-based polymer. A cell tya structure of a color liquid crystal display device characterized by being composed of a molecular film.