JP2007072302A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display, capable of maintaining display quality by suppressing distortions in the heat flexible layers facing a liquid crystal layer, with each having e.g. a construction wherein an optical compensation sheet is inserted between a polarizing plate and the liquid crystal cell in expansion/contraction due to thermal changes. <P>SOLUTION: In the liquid crystal display, having the heat flexible layers facing to the liquid crystal cell and having the optical compensation sheets, spaces are provided between the heat flexible layers and the liquid crystal cell. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device having a heat-flexible layer facing a liquid crystal cell.

  In a TN mode TFT liquid crystal display device which is currently mainstream, an optical compensation sheet is inserted between the polarizing plate and the liquid crystal cell to suppress the occurrence of a phase difference and to realize a liquid crystal display device with high display quality.

  Here, in JP-A-2-247602 (Patent Document 1), an elliptical polarizing plate having a retardation plate on one side of the polarizing film and a protective sheet on the other side is a factor for narrowing the viewing angle. The front contrast is increased without increasing the thickness of the liquid crystal display device. However, the retardation sheet (optical compensation sheet) of the present invention is likely to be distorted by heat, which leads to the generation of a retardation. In particular, in a heat flexible layer (for example, an optical compensation sheet) that is in close contact with the liquid crystal cell, distortion occurs due to the difference between the heat deformation rate of the glass of the liquid crystal cell and the heat deformation rate of the heat flexible layer. In the liquid crystal display device, a frame-like light leak (increased transmittance) is manifested, and the display quality of the liquid crystal display device is lowered.

  With respect to the problem of phase difference generation due to distortion, including such distortion, in the invention described in Japanese Patent Laid-Open No. 7-191217 (Patent Document 1), an optical made of a discotic (disk-shaped) compound on a transparent support. By using an optical compensation sheet coated with an anisotropic layer directly as a protective sheet for a polarizing plate, a solution to a problem relating to durability has been made without increasing the thickness of the liquid crystal display device.

Here, in recent years, the enlargement of the liquid crystal display device is remarkable, and accordingly, the distortion due to the above-described heat rise is becoming a problem again at the edge of the liquid crystal display device. When such distortion occurs, frame-like light leakage (increase in the transmittance of unnecessary light) occurs at the edge of the liquid crystal display device as described above, and the display quality of the liquid crystal display device decreases.
In general, since the optical compensation sheet is made of a transparent resin material, it has a high rate of expansion and contraction with respect to temperature, and there is a high possibility that such a frame-like light leakage (an increase in the transmittance of unnecessary light) will occur.
JP-A-2-247602 Japanese Patent Laid-Open No. 7-191217

  The present invention has been made in view of the above circumstances, and the problem is that a liquid crystal display device having a heat-flexible layer facing the liquid crystal cell, in particular, an optical compensation sheet is inserted between the polarizing plate and the liquid crystal cell. In the transmissive liquid crystal display device configured as described above, the transmissive liquid crystal can maintain the display quality of the liquid crystal display device by suppressing the distortion of the heat-flexible layer such as the optical compensation sheet at the edge of the liquid crystal display device even when the temperature rises. It is to provide a display device.

The above-mentioned subject concerning the present invention is attained by the following composition.
(1) In a liquid crystal display device having a heat-flexible layer facing a liquid crystal cell,
A liquid crystal display device in which a space is provided between the thermoflexible layer and the liquid crystal cell.
(2) The liquid crystal display device according to (1), wherein the heat-flexible layer is an optical compensation sheet disposed between a polarizing plate and a liquid crystal cell.

In a liquid crystal display device, a space is provided between the liquid crystal cell and the heat flexible layer facing the liquid crystal cell, so that the heat deformation rate of the liquid crystal cell and the heat deformation rate of the heat flexible layer are greatly different. However, since the generation of stress can be absorbed by the space provided between them, distortion due to the thermal deformation rate is not generated in the thermo-flexible layer facing the liquid crystal cell.
In particular, when the heat flexible layer facing the liquid crystal cell is an optical compensation sheet, an unnecessary phase difference is generated even if the heat deformation rate of the liquid crystal cell and the heat deformation rate of the heat flexible layer are significantly different. Distortion can be suppressed.

  According to the present invention, even if the thermal deformation rate of the liquid crystal cell and the thermal deformation rate of the thermo-flexible layer are greatly different, the generation of stress can be absorbed by the space provided between them, No distortion caused by the thermal deformation rate is generated in the thermo-flexible layer facing the liquid crystal cell. Therefore, even in a large-sized liquid crystal display device, the problem of distortion due to heat rise can be suppressed at the edge, and frame-like light leakage (increased unnecessary light transmittance) is suppressed, and the entire surface is covered. Thus, a liquid crystal display device with constant display quality can be provided.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing a laminated structure of a liquid crystal display device according to an embodiment of the present invention.
In this embodiment, a transmissive liquid crystal display device in which an optical compensation sheet is disposed between a polarizing plate and a liquid crystal cell is shown.

In the figure, an optical compensation sheet 13 is disposed in the liquid crystal display device 10 with a gap h between the liquid crystal cell 11, and a polarizer 15 and a protective layer 17 are sequentially adhered to the outside thereof to form a polarizing layer set 19. Be placed. Here, although the structure of the liquid crystal cell 11 is not illustrated, the liquid crystal cell 11 has a general structure in which liquid crystal, a color filter, a drive electrode, and the like are incorporated in a flat glass.
In this embodiment, since it is a transmissive liquid crystal display device, the polarizing layer set 19 is disposed on both surfaces of the liquid crystal cell 11.

  Since stress is transmitted by contact with respect to the distance of the gap h, it should be as small as possible unless contact is made, and 0.5 mm or less is appropriate at most. Above this, there is no problem in principle regarding display, but problems such as an increase in the thickness of the liquid crystal panel itself occur.

FIG. 2 is a cross-sectional perspective view and a partially enlarged view showing a gap forming configuration of the liquid crystal display device according to the embodiment of the present invention.
The liquid crystal display device 10 has a configuration in which the liquid crystal cell 11 and the polarizing layer set 19 are held by a frame 22 that covers the edges of the liquid crystal cell 11, and a mutual holding function exists on the surface portion of the liquid crystal cell 11 and the polarizing layer set 19 do not do. The detailed configuration is an enlarged view of a portion surrounded by a circle shown in a perspective view.

  In the partially enlarged view, the frame 22 is provided with a rib 24 for forming a gap h between the liquid crystal cell 11 and the polarizing layer set 19. At least the polarizing layer set 19 held between the ribs 24 is not fixed to the frame body 22 and is supported by the protruding length of the ribs 24. Therefore, when expansion and contraction due to heat occurs, a certain amount of distortion can be absorbed by providing a margin in the frame body 22 (with a slight gap).

Since there is no portion where the polarizing layer set 19 is supported by the liquid crystal cell 11, the liquid crystal cell 11 is hardly affected by expansion / contraction of the liquid crystal cell 11 due to temperature change. Therefore, even if the thermal deformation rate of the liquid crystal cell 11 and the thermal deformation rate of the polarizing layer set 19 are greatly different, the generation of stress is absorbed by the space provided between them, and the liquid crystal cell 11 is absorbed in the polarizing layer set 19. The distortion caused by the is not generated.
In a large liquid crystal display device, it is possible to suppress the distortion problem caused by the heat rise at the edge, which has been noticeable, and to suppress frame-like light leakage (increase in the transmittance of unnecessary light), over the entire surface. Display quality can be kept constant.

  In this embodiment, the transmissive liquid crystal display device in which the optical compensation sheet is disposed between the liquid crystal cell and the polarizer is referred to. However, other than this, the resin layer is in close contact with the liquid crystal cell, and the heat is applied. The present invention can be applied to any type of liquid crystal display device in which a flexible layer and distortion occur.

1 is a schematic cross-sectional view showing a laminated structure of a liquid crystal display device according to an embodiment of the present invention. The cross-sectional perspective view and partial enlarged view which show the space | gap formation structure of the liquid crystal display device by embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid crystal display device 11 Liquid crystal cell 13 Optical compensation sheet 15 Polarizer 17 Protective layer 19 Polarizing layer set 22 Frame body 24 Rib h Gap

Claims (2)

In a liquid crystal display device having a heat flexible layer facing a liquid crystal cell,
A liquid crystal display device in which a space is provided between the thermoflexible layer and the liquid crystal cell. The liquid crystal display device according to claim 1, wherein the heat-flexible layer is an optical compensation sheet disposed between a polarizing plate and a liquid crystal cell.

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