JP2751835B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a liquid crystal display device, and more particularly to a liquid crystal display device having a polarizing plate shape which does not cause display unevenness.

[0002]

2. Description of the Related Art Conventionally, in a film type liquid crystal display device, since the film substrate and the upper and lower polarizing films have different expansion and contraction ratios in the axial direction and the rigidity of the film substrate is low,
Under a high-temperature and high-humidity environment, the liquid crystal display device may be greatly warped or distorted. Even when the liquid crystal display device returns to the normal temperature and normal humidity environment, the warpage and the like are not eliminated, and the display performance and reliability of the liquid crystal display device are reduced. There is a problem that the property is reduced.

As a method for solving this problem, Japanese Patent Laid-Open No.
-315127 and JP-A-4-295822 have been proposed. This prior art structure is shown in FIG. In FIG. 3, (1) is a transparent insulating film substrate made of PET (polyethylene terephthalate), PES (polyethersulfone) or the like. This film substrate (1) has liquid crystal sealed and sealed therein. , A pair of substrates (1) provided with a transparent electrode for driving liquid crystal on the inner peripheral surface.
a) and (1b). On the upper and lower outer peripheral surfaces of the substrate (1), upper polarizing films (2) and (3) having a larger area than the film substrate (1) are fixed, and the lower polarizing films (2) and (3) are fixed thereon. ) Are formed with a plurality of insertion holes (2a) and (3a) at the four corners.

The upper and lower polarizing films (2) and (3) near the insertion holes (2a) and (3a) are provided with the films (2) and (3).
One surface of the reinforcing members (4) and (5) made of an acetate material, which is the same material as above, is bonded. The protrusions of the holding member are inserted into the insertion holes (2a) and (3a), and the other surface of the supply member (4) is bonded to the holding member. Reinforcing members (4) (5) in insertion holes (2a) (3a)
, The upper and lower polarizing films (2) and (3) can be uniformly pulled diagonally outward by inserting the protrusions of the holding member, and the film can be placed even in a high-temperature and high-humidity environment. Warping the substrate (1), upper and lower polarizing films (2) and (3),
This is to prevent the occurrence of distortion and the like, and to improve the display performance and reliability of the liquid crystal display device.

[0005]

However, in such a conventional technique, reinforcing members (4) and (5) are bonded to prevent warping and distortion of the upper and lower polarizing films, and the protrusions of the reinforcing members are formed. Upper and lower polarizing film (2) depending on the part
It is necessary to uniformly pull (3) outward diagonally. As a result, there is a problem that the manufacturing cost is increased. JP-A-63-8704 discloses a method of reducing distortion by making one side of a polarizing film uneven, and JP-A-4-368913 discloses a method of bonding a polarizing plate with an adhesive layer to form a solidified adhesive. It has been proposed to prevent distortion by making the thickness of the adhesive layer not affected by the displacement due to the expansion and contraction of the polarizing plate as the agent layer, but there was a very similar problem. An object of the present invention is to provide a liquid crystal display device having a polarizing plate shape that can improve the display performance and reliability of the liquid crystal display device without increasing the manufacturing cost.

[0006]

According to the present invention, there is provided a liquid crystal display device in which a liquid crystal is sandwiched between a pair of glass substrates on which a polarizing plate is adhered, and four corners of the polarizing plate have a curvature. The liquid crystal display device is characterized in that a radius of curvature of a corner portion with respect to a stretching axis direction of a polarizing film constituting the polarizing plate is larger than a radius of curvature of the other corner portion.

[0007]

[Function] In a high temperature and high humidity environment, the polarizing plate shrinks in the direction of the stretching axis. However, since the polarizing plate is fixed to the glass with an adhesive material, the conventional polarizing plate structure with four ends at a right angle has a polarizing plate peripheral portion and a central portion. The difference in the amount of distortion in the portion was large, and display unevenness failure occurred. In the present invention, by imparting a curvature to the four ends of the polarizing plate, when the polarizing plate tries to shrink in the stretching axis direction under a high temperature and high humidity environment, the amount of strain applied to the four ends of the polarizing plate is dispersed. This has the effect of reducing the difference in the amount of distortion between the central part and the peripheral part of the polarizing plate and reducing display unevenness defects caused by changes in optical characteristics around the display area. In addition, by making the curvature of the four ends of the polarizing plate larger in the extension axis direction corner portion than in the other corner portion, the amount of distortion in the extension axis direction with large expansion and contraction is more dispersed, so that the optical characteristics around the display area are reduced. This has the effect of eliminating display unevenness failure due to the change.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. Example 1 FIGS. 1A and 1B are a plan view and a sectional view showing a first example of a liquid crystal display device having a polarizing plate shape according to the present invention.
1A and 1B, a polarizing plate (13) having a thickness of 0.22 mm is formed on the surface of a liquid crystal display panel including a TFT substrate (11) and a color filter substrate (12) each having a thickness of 1.1 mm. Have been. The stretching axis direction of the polarizing plate (13) is (14). The polarizing film constitutes a polarizing plate.

The direction of the stretching axis (14) of the polarizing plate (13)
The radius of curvature of the corner (15) was 5 mm, and the radius of curvature of the other corners (16) was 5 mm. This liquid crystal display panel was left in an environment of high temperature and high humidity (60 ° C., 90% RH), and after 500 hours, the display state was confirmed. As shown in Table 1, display unevenness failure due to a change in optical characteristics around the display area was observed. The occurrence rate was 10%, which was greatly reduced compared to the conventional 100% occurrence rate of display non-uniformity defects in the case of a polarizing plate having four ends at right angles.

[Embodiment 2] FIGS. 2A and 2B are a plan view and a sectional view showing a second embodiment of the liquid crystal display device having a polarizing plate shape according to the present invention. In this embodiment, the first embodiment is used.
The same components as those described above are denoted by the same reference numerals and description thereof is omitted. In FIG. 2, the radius of curvature of the corner (17) in the stretching axis direction (14) of the polarizing plate (13) is 10 mm, and the radius of curvature of the other corners (18) is 5 mm. The liquid crystal display panel is left in an environment of high temperature and high humidity of 160 degrees and 90% RH,
When the display state was checked after 500 hours, as shown in Table 1, the occurrence rate of display unevenness failure due to a change in the optical characteristics around the display area was 0%, and the display unevenness failure occurred when the conventional four-sided polarizing plate shape was used. It did not occur at all compared to the rate of 100%.

[0011]

[Table 1]

[0012]

As described above, according to the present invention, when the polarizing plate has a curvature at its four ends, the polarizing plate can be shrunk in the stretching axis direction in a high-temperature and high-humidity environment. Since the distortion amount applied to the edges is dispersed, the difference in distortion amount between the central part and the peripheral part of the polarizing plate is reduced, and display unevenness due to a change in optical characteristics around the display area is reduced. Furthermore, by making the curvature of the corner portion in the polarizing plate stretching axis direction larger than that of the other corner portion, it is possible to eliminate the occurrence of display unevenness failure due to a change in optical characteristics around the display area. As described above, according to the present invention, it is possible to improve the display performance and the reliability of the liquid crystal display device only by devising the shape of the polarizing plate without increasing the manufacturing cost.

[Brief description of the drawings]

FIG. 1A is a plan view of a first embodiment of the present invention,
(B) is sectional drawing.

FIG. 2A is a plan view of a second embodiment of the present invention,
(B) is sectional drawing.

3A and 3B are structural views of a conventional liquid crystal display device, wherein FIG. 3A is a cross-sectional view and FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transparent insulating film substrate 2, 3 polarizing film 4, 5 reinforcing member 2a, 3a insertion hole 11 TFT substrate 12 color filter substrate 13 polarizing plate 14 stretching axis direction

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02F 1/1335 510 G02B 5/30

Claims (1)

(57) [Claims] 1. A liquid crystal display device in which a liquid crystal is sandwiched between a pair of glass substrates to which a polarizing plate is attached, and the shape of the four corners of the polarizing plate has a curvature, wherein the radius of the curvature is:
A liquid crystal display device, wherein a radius of curvature of a corner portion with respect to a stretching axis direction of a polarizing film constituting the polarizing plate is larger than a radius of curvature of the other corner portion.