JPH0235966B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal display element capable of color display, and particularly proposes a liquid crystal display element with improved contrast characteristics.

2. Description of the Related Art A liquid crystal display element capable of color display, which is a combination of a liquid crystal dot matrix and a multicolor polarizing plate having a pattern corresponding to the matrix electrodes, is being developed. Challenges during the development process include improving display density and color rendering. An effective solution to this problem is to make the dots smaller and increase the number of dots; however, due to the drive characteristics of liquid crystals, increasing the number of drive divisions causes crosstalk and degrades display quality. To prevent this, a multiple matrix method [as shown in Figure 3 for the double matrix method, the number of column (or row) electrodes is set to n (an integer, 2 or more) times the number of row (or column) electrodes. It is necessary to depend on what is available. In this multiple matrix method, the ratio of the display area to the non-display area, that is, the aperture ratio, is small, and compared to the area where light is actually transmitted or blocked by the liquid crystal, other light is transmitted. The area where the leakage occurs becomes wider and the contrast inevitably deteriorates.

This will be explained in a little more detail below.

Figure 1 shows a simple matrix electrode pattern, with layers of horizontally long electrodes Y ₁ to _{Y 4} arranged vertically in parallel,
A liquid crystal layer (not shown) is provided between the vertically long electrodes X ₁ to _{X 4} arranged horizontally, for example, the electrode Y _1
A colored polarizing film ₍ not _shown ) having _a pattern _aligned with _{the electrodes X 1 ,} (not shown) are arranged to form crossed Nicols. and transparent both electrodes X ₁ , X ₂ ~ _{X 6}
And when selective electric current is applied between Y ₁ and _{Y 4} ,
The area sandwiched between the electrodes (the intersection of the drawings) is displayed in color. FIG. 2 shows a pattern of such a display electrode portion. In the case of such a simple matrix method, the aperture ratio can be increased by narrowing the spacing between electrodes formed in the same layer, and the contrast can be increased by suppressing leakage light. It is limited by accuracy and the aforementioned crosstalk issues.

Figure 3 shows the electrode pattern for the double matrix method, where the electrodes are arranged in parallel in the horizontal direction.
It differs from the simple matrix method shown in Figure 1 in that X ₁ , _{X 2} , X ₃ and X 1 ′, X ₂ ′, X ₃ ′ are formed with complementary shapes. There is.

FIG. 4 shows the pattern of the display section of such a double matrix system, and FIG. 5 shows an enlarged view of two dots. The electrode parts B _{1 and} B ₂ connected to the display parts A 1 and A ₂ are formed as thin as possible so that they are difficult to see even when the display parts A ₁ and A ₂ are turned on, but if they are made too thin, the resistance value There is a limit because it becomes high and interferes with driving the liquid crystal. Furthermore, since the interelectrode gap shown by C does not affect the display, it is desirable to narrow the gap, but there is a limit due to etching accuracy.

For this purpose, the aperture ratio (A ₁ +A ₂ )/(A ₁ +A ₂ +B ₁
+B ₂ +C) × 100 (%) [A ₁ , A ₂ , B ₁ , B ₂ , C indicates the area of each part] must be as low as 60 to 70%, and the quadruple matrix method 50 in case
It drops to ~60%.

Therefore, in Fig. 5, when A ₁ and A ₂ are off, light passes through the entire surface, whereas when A ₁ and A ₂ are on, A ₁ , A ₂ , B ₁ , and B Since the light in the area ₂ is blocked and the light in the area C is transmitted, the light intensity ratio of these two areas, that is, the contrast, decreases. Furthermore, when only A ₁ is lit, B ₁ is lit, which also causes a decrease in contrast.

The present invention has been made by focusing on such a phenomenon, and provides a liquid crystal display element that is easy to manufacture and assemble, has no leakage of light from other colored areas, can suppress interference colors, and has high contrast. The purpose is to provide

The liquid crystal display element according to the present invention is a cell that combines a liquid crystal layer, display electrode parts disposed on both sides of the liquid crystal layer for applying voltage to the liquid crystal layer, and a colored polarizing layer disposed on the display surface side. In the dot matrix type liquid crystal display element, the colored polarizing layer has a colored region at a position corresponding to the display electrode section for applying voltage to the liquid crystal layer, and a light blocking section at a position not corresponding to the display electrode section. It is characterized in that it is composed of a single film member having a structure formed thereon, and is provided at a position on the inner wall of the cell and close to the display electrode section.

FIG. 6 is a pattern diagram of the device of the present invention in a simple matrix system, in which a region corresponding to the display electrode portion A is left and the other regions are used as light blocking portions (shown with hatching).

FIG. 7 is a pattern diagram of the device of the present invention in a double matrix system, in which areas corresponding to the display electrodes A ₁ and A ₂ are left, and the other areas are used as light blocking portions (shown with hatching). .

FIG. 8 is a pattern diagram when the present invention is applied to a liquid crystal display element for full color display, and is of a quadruple matrix type. Each display electrode part A ₁ , A ₂ ,
A ₃ and A ₄ are modes in which eight display electrode sections are formed in one cycle in order to secure a formation area for narrow electrode sections (corresponding to B ₁ and B ₂ in Fig. 5) that connect each display electrode section. They are arranged in slightly shifted positions. Such narrow electrode part and inter-electrode gap part (corresponding to C in Fig. 5)
A light blocking portion (shown with hatching) is formed in the portion. The display electrode portions arranged in parallel in the same vertical column each contribute to the development of the same color, and in the illustrated portion, red (), green (), and blue () are arranged in this order from the leftmost column.

Such a light blocking portion is formed, for example, in the same layer as the colored polarizing film for color development using a black dye that absorbs light without imparting a polarizing function. Next, based on FIG. 9, 1 of the manufacturing method of the device of the present invention
An example will be explained. First, spread the PVA membrane in one direction for 2~
The stretched PVA film 2, which has been stretched five times, is adhered onto the glass transparent substrate 1 using a PVA adhesive [FIG. 9A]. Next, as shown in FIG. 9B, the membrane 2
Apply a photoresist 3 to an appropriate thickness on top, and apply a second color (e.g. green) and a third color (e.g. blue) to the areas corresponding to the display electrodes A ₁ , A ₂ , A ₃ , A ₄ . Using a mask (not shown) with a pattern that exposes the area to be exposed, this area is cured, and the uncured area that is not exposed to light is dissolved and removed by a development process, as shown in Figure 9 (H). As shown in the display electrode parts A ₁ , A ₂ ,
The portions of the surface of the film 2 where the first color (for example, red) should be developed are exposed in the portions corresponding to A ₃ and A ₄ . The photoresist 3 is then colored with polarized ink 4 made of iodine and a first color dye (FIG. 9D), and then the photoresist 3 is peeled off as shown in FIG. 9E. As a result, the first colored region 21 is formed in the film 2.

When the above-mentioned process from photoresist coating to peeling is repeated for the second and third colors, a second color colored area 22 and a third color colored area 23 are formed on the transparent substrate 1 as shown in FIG. A state in which the two are formed in parallel is obtained.

Furthermore, as shown in FIG. 9, a photoresist 3' is applied onto the film 2, and exposed using a mask (not shown) with a pattern that exposes only the portions that are to become display electrodes. This portion is cured, and the unexposed, uncured portion is dissolved and removed by a development process, thereby exposing the film surface of the portion where the light blocking portion is to be formed, as shown in FIG. 9C. The photoresist 3' is then colored with a light-absorbing dye 5 that does not provide a polarizing function (FIG. 9-R), and then the photoresist 3' is peeled off as shown in FIG. 9--. As a result, a light blocking portion 20 is formed at a desired portion of one film 2.

FIG. 10 shows a cross-sectional structure of the device of the present invention having a cell structure manufactured in this way. (In other words, the direction in which the colored regions 21, 22, 23 extend...
A large number of parallel electrodes Y (extending in a direction perpendicular to the front and back directions of the drawing) are formed, and an alignment layer 6, a liquid crystal layer 7, and another alignment layer 8 are provided on the upper layer. Electrodes X ₁ , X ₂ , X ₃ , . . _. The neutral polarizing plate 10 is combined with the colored polarizing film to form crossed Nicols.

As a result of this, as is clear from Figure 10, the electrode
Colored regions 21, ₂₂ , and 23 are located at positions corresponding to the display electrodes consisting of X ₁ , X ₂ , X ₃ , ... 20 is located.

In such an element of the present invention, the colored polarizing layer has a colored region formed at a position corresponding to the display electrode section for applying voltage to the liquid crystal layer, and a light blocking section formed at a position not corresponding to the display electrode section. Because of this, the color filter, polarizing plate, and light shielding parts, which were conventionally constructed separately, are now integrally formed into a single film. There is no need for a structure, and a single film can provide filter, polarization, and light blocking functions, making it easy to handle,
Manufacturing and assembly are easy, and since the light blocking part can be formed simultaneously during the coloring process using a polarizing film, no unevenness will occur between the colored area and the display electrode and liquid crystal layer. The colored polarizing layer can be provided on the inner wall of the cell and positioned close to the display electrode, and the influence of parallax can also be reduced. Furthermore, since there is no difference in level between the colored polarizing layer and the light blocking section, the color separation becomes clearer, effectively preventing the leakage of light that would reduce the contrast, and not only improving the contrast, but also improving the display of each color. The color purity is also improved because the color is not diluted by transmitted white light. When we compared and measured the black-and-white light intensity ratio between the device of the present invention and a conventional product that does not have a light blocking part, it was 2.0 for the conventional product, but 2.9 for the device of the present invention (however, the aperture ratio was 55% for both). Therefore, the effect of the present invention was verified.

[Brief explanation of drawings]

Figure 1 is an electrode pattern diagram of the simple matrix method, Figure 2 is a pattern diagram of its display electrode section, and Figure 3 is a diagram of the electrode pattern of the simple matrix method.
The figure is a diagram of the electrode pattern of the double matrix system, FIG. 4 is a pattern diagram of the display electrode part, FIG. Figures 1 to 1 are explanatory views of the method of manufacturing the device of the present invention, and Fig. 10 is a cross-sectional structural diagram of the device of the present invention. A ₁ , A ₂ , A ₃ , A ₄ ... Display electrode section, 1 ... Transparent substrate, 2 ... Polarizing film, 7 ... Liquid crystal layer, X ₁ , X ₂ ,
_X3 ... _Xo , Y, _Y1 , _Y2 ...Transparent electrode.

Claims (1)

[Claims] 1. A cell structure that combines a liquid crystal layer, display electrodes disposed on both sides of the liquid crystal layer for applying voltage to the liquid crystal layer, and a colored polarizing layer disposed on the display surface side. In the dot matrix type liquid crystal display element, the colored polarizing layer has a colored region at a position corresponding to a display electrode section for applying a voltage to the liquid crystal layer, and a light blocking section at a position not corresponding to the display electrode section. What is claimed is: 1. A liquid crystal display element, characterized in that the liquid crystal display element is constituted by a single film member having a membrane structure and is provided on an inner wall of the cell at a position close to a display electrode section. 2. The liquid crystal display element according to claim 1, wherein the light blocking portion uses a light-absorbing dye that does not provide a polarizing function.