JPH0344624A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To eliminate a defect in the orientation of liquid crystal by setting the ratio of the area of one picture element part and the height of a switching element part or signal line parts above a specific value. CONSTITUTION:The signal line parts 2, switching element part, etc., are formed on an electrode substrate 1 made of glass and an orienting film 5 is formed between the signal line parts 2. The ratio of the area of one film 5 and the height (h) of the signal line parts 2 or switching element is set to >=(6,000mum<2>: 1mum). Consequently, neither of parts (a) and (b) of the film 5 against which cloth is rubbed comes to defective in orientation, and excellent orientation is obtained over entire area.

Description

[Detailed description of the invention] Industrial applications The present invention ζ1 relates to a liquid crystal display device such as a liquid crystal television.

Conventional technology Alignment films are used to provide orientation to liquid crystals. This alignment film 41 is a polymer film such as polyimide provided on opposing surfaces of an electrode substrate having switching elements and the like and a substrate having color filters, and is rubbed with a cloth or the like in the alignment direction.

Problems to be Solved by the Invention In conventional liquid crystal display devices, fatal defects such as light leakage and omission, and a decrease in the fidelity of displayed colors could occur in the periphery of one pixel. And the cause 4
1 It was discovered that the sliding defect of the alignment film in the peripheral area of the pixel was caused by the difference in level between the pixel part 3 and the signal line part 2 shown in FIG. The area around one pixel is not sufficiently rubbed with cloth a
The ib portion is formed on the alignment film, and the above-mentioned disadvantage occurs because the liquid crystal is not sufficiently aligned in this portion.

Means for Solving the Problems And means for solving the above problems (ratio of the area of one pixel section and the height of the switching element section that drives the liquid crystal and the signal line section that controls the switching element) is greater than a certain value.

Effects of the above means, ie, the plate As a function of making the above ratio above a certain value, the alignment pattern in the central part of the pixel rubbed with cloth spreads to the ai [l b part and is good in the entire pixel area. This gives a good orientation.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a cross-sectional view of an electrode substrate 1 of a liquid crystal display device, which is an embodiment of the present invention, taken along a plane parallel to the liquid crystal orientation direction e. Part 2: A plate on which switching elements, etc. are formed.Furthermore, a thin film of about 1,200 polymeric materials such as polyimide, which forms the alignment film 5, is formed on the entire surface of the glass substrate using techniques such as screen printing. .

Now, parts a and b of "the part that is not sufficiently rubbed with cloth"
The part 4 in FIG. 1 is the part on the cloth. It is well known that by mechanically rubbing the alignment film 5 in this way, the liquid crystal will be oriented in the direction of the rubbing.

Now, at this time, the cloth 4 rides on the signal line part 2. As a result, the height h of the signal line part 2 and the angle θ at which the cloth 4 contacts the alignment film 5 on the electrode substrate 1 are Part a, which is the base of the triangle, is the part that is not sufficiently rubbed by the cloth.

Moreover, after riding on the signal line part 2 on the cloth 4, when it moves in the liquid crystal alignment direction e, it comes into contact with the pixel part 3.

This group: The speed at which the cloth 4 moves in the liquid crystal orientation direction e, and the cloth 4
In relation to the height h of the wiring part 2, part b of ``the part that is not sufficiently rubbed with cloth'' may be formed due to the mechanism described above. FIG. 2 shows a plan view of the parts "a" and "b" that are not rubbed.

3 in Figure 2 (one pixel section, size 80μm x
It is 75 μm. 2 (melon) This is a signal line portion that controls the switching element 5. Then, in order to orient the liquid crystal, it is rubbed with a cloth in the diagonal direction e.

``Parts not rubbed with cloth'' a and b explained in Fig. 1 above
The corresponding parts are a' and b' shown by hatching.

Also, "the part rubbed with cloth" is C.

Then, ``Parts J a 7 and b' that are not rubbed with cloth
We conducted an analysis of the orientation of liquid crystals in this section.
It is important to note that the force that orients the liquid crystal in the "portion rubbed by the cloth"C' in the center of the pixel has an influence on the above a' and b' areas, and that there is a limit to the range of its influence. This finding suggests that it is not necessarily necessary to completely eliminate the La section and the b section, that is, to make the alignment film 5 a "portion rubbed with cloth" over the entire surface of the pixel.

Therefore, in order to further determine this limit, we conducted the following experiment. (9) When the shape of the pixel part was set to be approximately square or approximately circular, 1) When the height h of the wiring part was varied while keeping the area of the pixel part constant. 2) Orientation of liquid crystal when the height h of the wiring part is kept constant and the area of the pixel part is changed. Regarding the ratio to the height, the following facts were found. When the area of one pixel part is 6000 μm2, if the height of the signal line part is 1 μm or less, the liquid crystal around the pixel, which was a problem in the past, Second, the above ratio is 6000 μm2:
If it is 1 μm or more, the above effect is guaranteed. , And, it has been confirmed that this also holds true for the relationship between the heights of the pixel section and the switching element section 6, and thirdly, (above) Regarding the am b section that occurs at the ratio of 6000 μm2: 1 μm or more, First, there should be no poor orientation.

The present invention can be easily implemented even at a mass production level, and the effects of the invention can be solved by solving the conventional problems.As explained in detail above, the present invention has the advantage of reducing the area of one pixel and the signal line or switching area. By focusing on the ratio to the height of the element part, it is possible to easily and reliably solve problems caused by poor alignment of conventional liquid crystals.

[Brief explanation of drawings]

FIG. 1 C: A cross-section of the main parts of the present invention is shown in FIG. 2: A plan view showing an overview of the present invention.
・・・Pixel starvation 4．．．Fukumo 5．．・・・Orientation 1
11L6...Switching element, h...Height of signal line part &a, b...portion not rubbed by cloth, θ...Angle where the hairs come into contact, e.・
...Liquid crystal alignment direction

Claims (1)

[Claims] In a liquid crystal display device having an alignment film that provides alignment of liquid crystal in the direction of the rubbing by mechanical rubbing, controlling the area of one pixel part and a switching element part for driving the liquid crystal or the switching element. A liquid crystal display device characterized in that the ratio of the height of the signal line portion to the height of the signal line portion is 6000 μm^2 to 1 μm or more.