JPH04289823A - Liquid crystal display panel - Google Patents

Abstract

PURPOSE:To provide a good and uniform display in a panel total surface, relating to a liquid crystal display panel. CONSTITUTION:In the case of a liquid crystal display panel having transparent electrodes 1a, 1b and sealing a liquid crystal 5 between a pair of transparent substrates 3a, 3b, applying an orientation processed film to the surface, to form a picture element part by an overlapped part of these transparent electrodes, an orientation processing film 7b' of a non-picture element part has at least partly a pretilt angle larger than the pretilt angle of the orientation processing film 7b of the picture element part.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a liquid crystal display panel.
More specifically, the present invention relates to a structure of a liquid crystal display panel that aligns liquid crystal molecules more uniformly over the entire surface of the panel, regardless of whether it is a pixel part or a non-pixel part. Liquid crystal display panels have already been applied in many fields, and in particular, active element type liquid crystal panels, in which the voltage of each pixel is controlled by active elements, are commercially available as portable televisions because they have display characteristics comparable to those of CRTs. In addition, large-screen display panels are being actively developed.

0002

2. Description of the Related Art An example of the structure of a conventional active element type liquid crystal display panel is shown in FIG. As is well known, the liquid crystal cell has a transparent electrode 1a.
, 1b (pixel electrodes).
A liquid crystal 5 is sealed between the liquid crystal 5 and the glass surfaces facing each other with the liquid crystal 5 interposed therebetween.
is formed. Liquid crystal alignment film 7 that regulates the alignment of liquid crystal molecules
a and 7b are formed as a uniform film on the entire glass surface,
This alignment film is subjected to a uniform rubbing treatment. Through this rubbing process, the liquid crystal molecules are aligned in a predetermined constant direction (rubbing direction), and the liquid crystal molecules at the interface have an initial tilt angle (pretilt angle) in the same direction of about 0 to 2 degrees with respect to the substrate. become.

0003

[Problem to be solved by the invention] However, in this case,
Since the interface where the liquid crystal 5 contacts the alignment films 7a and 7b, especially the pixel electrode 1b, is not flat due to the presence of the electrode 1b, the bus line (power supply line) 9, etc., the uniformity of the liquid crystal alignment may be partially disturbed. There is. In particular, as a result of the alignment of liquid crystal molecules near the bus line 9 being disturbed by the influence of liquid crystal molecules in contact with the side surfaces of the bus line, the liquid crystal molecules may have a pretilt angle that is opposite to the original pretilt angle.

When such an area occurs, a small area (hereinafter referred to as an abnormal area) in which the direction in which the liquid crystal molecules rise when a voltage is applied is opposite to the original direction occurs near the bus line 9, and this abnormal area is a pixel. There is no problem as long as it does not reach the display pixel 1b, but if it reaches the display pixel 1b, the boundary with the normal area becomes a problem as a display defect.

[0005] In order to prevent the occurrence of such abnormal areas, it is simply possible to increase the effect of tilting the liquid crystal molecules by increasing the pretilt angle of the panel, but as is well known, This was not a practical solution because increasing the pretilt angle would deteriorate the viewing angle characteristics of the panel.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to prevent the occurrence of such abnormal areas, thereby making it possible to achieve good and uniform display over the entire panel.

In order to achieve the above object, in the liquid crystal display panel according to the present invention, at least a part of the liquid crystal alignment film in the non-pixel area has a pretilt angle larger than the pretilt angle of the liquid crystal alignment film in the pixel area. It is a structural feature. When the liquid crystal display panel is an active element type liquid crystal display panel having a bus line, a pretilt angle larger than the pretilt angle of the liquid crystal alignment film portion in the pixel portion is given to the liquid crystal alignment film portion on the bus line, which is a non-pixel 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. Furthermore, the pretilt angle of the liquid crystal alignment film portion can be easily imparted by varying the rubbing conditions.

[0009]

[Operation] FIG. 1 shows a diagram of the principle of the present invention. An alignment film 7b similar to the conventional one is formed in the pixel part 1b, and an alignment film 7b' having a higher pretilt angle than the pixel part 1b is formed on the bus line 9, which is a non-pixel part. This increases the effect of aligning the tilt direction and angle of the liquid crystal molecules in the vicinity of the bus line 9, so it is possible to prevent the abnormal region from occurring without deteriorating the viewing angle characteristics.

Generally, the pretilt angle of a liquid crystal alignment film is determined by the material of the alignment film and the rubbing conditions, as is well known. Therefore, the high pretilt alignment film 7b' formed in the non-pixel area 9
(1) Use a high pretilt alignment film material that is different from the material of the alignment film 7b (or 7a) formed in the pixel portion 1b (or 1a), or (2) The alignment film material itself is made of glass. Two methods can be considered: forming the same film over the entire surface of the substrate 3b and using different rubbing conditions for the pixel portion 1b and the non-pixel portion 9.

[0011]

Embodiment FIG. 2 shows an embodiment of the present invention. FIG. 2 is an enlarged view of section A in FIG. T with 640 x 400 pixels
An FT liquid crystal display was manufactured. After forming an alignment film 7b on the pixel portion 1b and an alignment film 7b' on the bus line 9 by patterning, a rubbing process was simultaneously performed under the same conditions. The pretilt angle θ0 of the alignment film 7b on the pixel portion 1b is 1.5 degrees (θ0 = 1.5°), and the pretilt angle θ0 of the alignment film 7b' on the bus line 9 is 1.5 degrees (θ0 = 1.5°).
1 has three different alignment films (θ1 = 1.5°, 2.5
(in other words, three different liquid crystal display panels were manufactured). Incidentally, C is a liquid crystal molecule shown schematically to indicate a pre-chilled angle. When a television display was performed on the fabricated panel, the pretilt angle θ1 of the alignment film 7b' was 1.5 degrees (θ
1 = 1.5°), a display defect occurred due to the occurrence of an abnormal area, whereas the other two panels in which the pretilt angle θ1 of the alignment film 7b' was larger than 1.5 degrees (=θ1 = θ0) LCD panel (θ1 = 2.5°, θ
1 = 3.5°), such display defects did not occur and a good display was obtained.

Furthermore, although the alignment film material was changed in the above embodiment, similar effects can also be achieved by changing the rubbing conditions. For example, taking advantage of the fact that the pretilt angle of the liquid crystal alignment film generally decreases as the number of times of rubbing increases, the number of times of rubbing for pixel areas is greater than the number of times of rubbing for non-pixel areas. Such nonuniformity of the rubbing process within the same panel can be easily achieved, for example, by masking the surface of the alignment film in non-pixel areas with a resist or the like when rubbing is applied to pixel areas.

In the embodiments described above, the bus line was used as an example of the non-pixel portion, but the basic concept of the present invention is to make the pretilt angle of the alignment film different between the pixel portion and the non-pixel portion. There is no problem with the configuration of the part and the non-pixel part.

[0014]

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

[Brief explanation of the drawing]

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

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

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

[Explanation of symbols]

1a, 1b...transparent electrodes 3a, 3b...Glass substrate 5...Liquid crystal 7a, 7b, 7b'...alignment film 9...Bus line

Claims (4)

[Claims] Claim 1: A pair of transparent substrates (3a, 3b) having transparent electrodes (1a, 1b) and whose surfaces are subjected to alignment film treatment.
In a liquid crystal display panel in which a liquid crystal (5) is sealed between the transparent electrodes and a pixel part is formed by the overlapping part of the transparent electrodes, at least a part of the liquid crystal alignment film part (7b') in the non-pixel part is used for liquid crystal alignment in the pixel part. A liquid crystal display panel characterized in that it has a pretilt angle (θ1) larger than a pretilt angle (θ0) of the film portion (7b). Claim 2: The liquid crystal display panel has a bus line (9
), and the liquid crystal alignment film part (7b') on the bus line, which is a non-pixel part, has a pretilt angle (θ0) of the liquid crystal alignment film part (7b) in the pixel part.
The liquid crystal display panel according to claim 1, having a larger pretilt angle. 3. 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 different material from the liquid crystal alignment film portion formed in the pixel portion. The liquid crystal display panel according to claim 1 or 2. 4. The pretilt angles of the liquid crystal alignment film portion in the pixel portion and the liquid crystal alignment film portion in the non-pixel portion are provided by different rubbing conditions. LCD display panel.