JP2910790B2 - LCD panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display panel.
More specifically, the present invention relates to a configuration of a liquid crystal display panel that more uniformly aligns liquid crystal molecules on the entire surface of a panel regardless of a pixel portion or a non-pixel portion. Liquid crystal display panels have already been applied to many fields. In particular, an active element type liquid crystal panel that controls the voltage of each pixel with an active element can provide a display characteristic comparable to that of a CRT, and is therefore commercially available as a portable television. Besides, large-screen display panels are being actively developed.

[0002]

2. Description of the Related Art FIG. 3 shows a structural example of a conventional active element type liquid crystal display panel. As is well known, a liquid crystal cell has a transparent electrode 1.
a, a pair of glass substrates 3a having 1b (pixel electrode),
The liquid crystal 5 is sealed between the liquid crystal molecules 3b, and the glass surfaces facing each other with the liquid crystal 5 interposed therebetween are subjected to an alignment treatment, and the liquid crystal molecule alignment films 7a, 7
b is formed. The liquid crystal alignment films 7a and 7b for regulating the alignment of the liquid crystal molecules are formed as a uniform film on the entire surface of the glass, and a uniform rubbing treatment is applied to the alignment film. The rubbing process aligns the liquid crystal molecules in a predetermined direction (rubbing direction), and the liquid crystal molecules at the interface have an initial tilt angle (pretilt angle) of about 0 to 2 degrees with respect to the substrate in the same direction. become.

[0003]

However, in this case,
Since the interface between the liquid crystal 5 and the alignment films 7a and 7b, particularly the interface in contact with the pixel electrode 1b is not planar due to the presence of the electrode 1b and the bus line (power supply line) 9, the uniformity of liquid crystal alignment is partially disturbed. There is. In particular, the liquid crystal molecules near the bus line 9 are disturbed in alignment by the influence of the liquid crystal molecules in contact with the side surface of the bus line, and as a result, may have a pretilt angle opposite to the original pretilt angle.

When such a region is generated, a small region (hereinafter, referred to as an abnormal region) in which the rising direction of the liquid crystal molecules at the time of voltage application is opposite to the original direction is generated near the bus line 9, and this abnormal region is a pixel. There is no problem as long as it does not reach the portion, but when it reaches the display pixel 1b, the boundary with the normal region becomes a problem as a display defect.

To prevent the occurrence of such an abnormal region, simply increasing the pretilt angle of the panel may increase the effect of orienting the liquid crystal molecules in a tilted direction. However, when the pretilt angle is increased, the viewing angle characteristic of the panel is deteriorated, and this is not a practical solution.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to prevent the occurrence of such an abnormal area so that a good and uniform display can be realized on the entire panel.

In order to achieve the above object, in an active element type liquid crystal display panel according to the present invention, the liquid crystal display panel has a bus line. It is characterized by having a pretilt angle larger than the pretilt angle of the alignment film portion.

Preferably, the liquid crystal alignment film portions of the pixel portion and the non-pixel portion having different pretilt angles are formed of different materials. Further, the pretilt angle of the liquid crystal alignment film portion can be easily given by changing the rubbing conditions.

[0009]

FIG. 1 shows the principle of the present invention. An alignment film 7b similar to the conventional one is formed in the pixel portion 1b, and an alignment film 7b 'having a higher pretilt angle than the pixel portion 1b is formed on the bus line 9 which is a non-pixel portion. As a result, the effect of aligning the tilt direction and the angle of the liquid crystal molecules near the bus line 9 is increased, so that the occurrence of the abnormal region can be prevented without deteriorating the viewing angle characteristics.

Generally, the pretilt angle of a liquid crystal alignment film is determined by the alignment film material and rubbing conditions, as is well known. Therefore, the high pretilt alignment film 7b 'formed in the non-pixel portion 9
(1) using an alignment film material for high pretilt, which is different from the material of the alignment film 7b (or 7a) formed on the pixel portion 1b (or 1a), or (2) the alignment film material itself is glass There are two methods of making the same film over the entire surface of the substrate 3b and making the rubbing conditions different between the pixel portion 1b and the non-pixel portion 9.

[0011]

FIG. 2 shows an embodiment of the present invention. FIG. 2 is an enlarged view of a portion A in FIG. T with 640 × 400 pixels
An FT liquid crystal display was manufactured. After forming the alignment film 7b in the pixel portion 1b and the alignment film 7b 'on the bus line 9 by patterning, a rubbing treatment was performed simultaneously under the same conditions. The pretilt angle θ ₀ of the alignment film 7b on the pixel portion 1b is 1.5 degrees (θ ₀ = 1.5 °), and the pretilt angle θ ₁ of the alignment film 7b ′ on the bus line 9 has three different alignments. Films (θ ₁ = 1.5 °, 2.5 °, 3.5 °) were fabricated (ie, three different liquid crystal display panels were fabricated).
Note that C is a liquid crystal molecule schematically shown to indicate a pretild angle. When television display was performed on the manufactured panel, the pretilt angle θ ₁ of the alignment film 7b ′ was 1.5 degrees (θ ₁
= 1.5 °), a display defect occurred due to the occurrence of an abnormal region, whereas the pretilt angle θ of the alignment film 7b 'was
_{On the} other two liquid crystal panels (θ ₁ = 2.5 °, θ ₁ = 3.5 °) where ₁ is larger than 1.5 degrees (= θ ₁ = θ ₀ ), such display defects do not occur and are good. Display was obtained.

In the above embodiment, the material of the alignment film is changed. However, a similar effect can be realized by changing the rubbing conditions. For example, by utilizing the fact that the pretilt angle of the liquid crystal alignment film generally decreases as the number of rubbing increases, the number of rubbing in the pixel portion is set to be larger than that in the non-pixel portion. Such non-uniformity of the rubbing process in the same panel can be easily realized by, for example, rubbing the pixel portion by masking the alignment film surface of the non-pixel portion with a resist or the like.

In the embodiment described above, the bus line is exemplified as the non-pixel portion. However, the basic concept of the present invention is to make the pre-tilt angle of the alignment film different between the pixel portion and the non-pixel portion. The configuration itself of the unit and the non-pixel unit does not matter.

[0014]

As described above, according to the present invention, uniform display is realized on the entire surface of the liquid crystal panel, so that the display quality of the panel can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a basic configuration of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG. 1 showing the embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional liquid crystal display panel.

[Explanation of symbols]

 1a, 1b: transparent electrode 3a, 3b: glass substrate 5: liquid crystal 7a, 7b, 7b ': alignment film 9: bus line

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Sasabayashi 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Osamu Morishige 1015 Kamidanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited ( 56) References JP-A-53-117453 (JP, A) JP-A-60-22118 (JP, A) JP-A-4-55819 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , (DB name) G02F 1/1337

Claims (3)

(57) [Claims] 1. A liquid crystal (5) is sealed between a pair of transparent substrates (3a, 3b) each having a transparent electrode (1a, 1b) and having a surface subjected to an alignment film treatment, and an overlapping portion of the transparent electrodes. In the liquid crystal display panel forming a pixel portion, the liquid crystal display panel is an active element type liquid crystal display panel having a bus line (9), and a liquid crystal alignment film portion (7b ') on the bus line as a non-pixel portion is a pixel. Part of liquid crystal alignment film part (7b)
A liquid crystal display panel having a pretilt angle (θ ₁ ) larger than the pretilt angle (θ ₀ ). 2. The liquid crystal alignment film portion of the non-pixel portion having a pretilt angle larger than the pretilt angle of the liquid crystal alignment film portion of the pixel portion is formed of a material different from that of the liquid crystal alignment film portion formed in the pixel portion. The liquid crystal display panel according to claim 1, wherein 3. The liquid crystal alignment film in the pixel portion and the liquid crystal alignment film in the non-pixel portion have different pretilt angles given by different rubbing conditions.
The liquid crystal display panel according to 1.