JP2001100235A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a liquid crystal display device in which the temperature of a liquid crystal cell is uniformly increased in a low temperature environment to improve the display quality. SOLUTION: The liquid crystal display device has a liquid crystal cell holding a liquid crystal between two substrates and has a heater glass to heat the liquid crystal cell. The device features that heat generators of different patterns are formed respectively on one face and on the other face of the heater glass.

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 device, and more particularly to a liquid crystal display device having improved operation in a low temperature environment.

[0002]

2. Description of the Related Art In a conventional liquid crystal display device, a heater is added in order to ensure the operation performance because the operation speed of the liquid crystal is rapidly reduced in a low temperature environment. FIG.
FIG. 1 is a schematic view of a configuration of a liquid crystal display device to which a conventional heater is added, which is disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 59-228290.

In FIG. 4, a liquid crystal display device is a liquid crystal cell 1.
And the heater glass 2. Liquid crystal cell 1 is 2
Liquid crystal is filled between the glass substrates, and the heater glass 2 is brought close to one surface of the glass substrate. In addition, the liquid crystal cell 1
Is a valid display area 11 where the display is valid.

FIG. 5 is a plan view of the heater glass 2. In FIG. 5, a heater glass 2 has a structure in which a transparent conductive film (hereinafter, referred to as ITO) 3 as a heating element is vapor-deposited on one surface of a glass substrate, and electrodes 4 such as gold are provided on both ends thereof. Have been.

The surface of the heater glass 2 on which the ITO is not deposited is brought close to the liquid crystal cell 1, and in a low temperature environment, the heater glass 2 is heated by energizing the ITO via the electrode 4 and the heat causes the liquid crystal cell to be heated. The operation of the liquid crystal display device is ensured by heating.

[0006]

However, in a low temperature environment, the temperature of the periphery of the liquid crystal cell 1 tends to decrease more than that of the central portion, so that the temperature distribution becomes non-uniform.
Due to the distortion or the like existing in the glass itself constituting the liquid crystal cell, the temperature rise rate of the liquid crystal cell 1 also has a large difference between the central portion and the peripheral portion of the screen.

As a result, for example, when a black screen is displayed, a difference in the brightness of the liquid crystal appears due to a difference in temperature between the central portion and the outer edge portion, and a so-called "white spot" appears in the peripheral portion.
And there is a problem that the display quality is remarkably deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has been made in a low-temperature environment.
It is an object of the present invention to realize a liquid crystal display device in which the temperature is uniformly raised and display quality is improved.

[0009]

According to a first aspect of the present invention, there is provided a liquid crystal display device having a liquid crystal cell sandwiching a liquid crystal between two substrates, and a heater glass for heating the liquid crystal cell. A liquid crystal display device characterized in that heating elements of different patterns are formed on one surface and the other surface of glass, respectively.

[0010] According to a second aspect of the present invention, the heating element is formed in a stripe shape so as to form a grid on one surface and the other surface of the heater glass. 1 is a liquid crystal display device.

According to a third aspect of the present invention, the striped heating element is formed so that a central portion of the heater glass is sparse and a peripheral portion is dense.
It is a liquid crystal display device of the statement.

According to a fourth aspect of the present invention, the striped heating elements formed on one side and the other side of the heater glass are electrically connected to each other. It is a liquid crystal display device of the statement.

According to a fifth aspect of the present invention, in a liquid crystal display device having a liquid crystal cell sandwiching a liquid crystal between two substrates and a heater glass for heating the liquid crystal cell, one surface of the heater glass is provided. A liquid crystal display device comprising: a heating element for heating the entire surface of the liquid crystal cell; and a heating element for heating the outside of the effective display area of the liquid crystal cell on the other surface.

According to a sixth aspect of the present invention, in a liquid crystal display device having a liquid crystal cell sandwiching a liquid crystal between two substrates, and a heater glass for heating the liquid crystal cell, the liquid crystal cell has a heater glass. A liquid crystal display device comprising a heating element that heats the outside of the effective display area of the liquid crystal cell on a side that is not close to the liquid crystal cell.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings. In the following drawings, FIG.
Portions that overlap with 5 are given the same numbers, and descriptions thereof are omitted as appropriate. FIG. 1 is a plan view of a heater glass constituting one embodiment of the present invention, in which (a) is a front view and (b) is a rear view.

1A and 1B, the heater glass is composed of a glass substrate 20, and heating elements 31, 32 and electrodes 41, 42 formed on both surfaces of the glass substrate 20.

In FIG. 1A, a heating element 31 is formed by depositing ITO formed on a glass substrate 20 by vapor deposition or the like.
In parallel with the longitudinal direction of 0, the central portion is sparsely patterned so that the outer edge portion is dense. The electrodes 41 are made of a metal such as gold, for example, and are formed at both ends in the longitudinal direction of the glass substrate 20 so that the striped heating elements 31 are electrically connected to each other.

In FIG. 1B, the heating element 32 is made of ITO formed on the glass substrate 20 by, for example, vapor deposition or the like, perpendicular to the longitudinal direction of the glass substrate 20, the center is sparse, and the outer edge is dense. It is formed by patterning in a striped manner. The electrodes 42 are made of a metal such as gold, for example, and are arranged and formed at both ends in the lateral direction of the glass substrate 20 so that the heating elements 32 formed in a stripe shape are electrically connected to each other.

As described above, the heater glass is connected to the heating element 3.
The heaters 1 and 32 constitute a matrix heater in which the center is substantially sparse on the front and back sides and the outer edge is dense. Further, if the electrodes 41 and 42 are formed so as to be connected to each other at the corner 50, the power supply to the heating elements 31 and 32 can be unified.

Then, similarly to the liquid crystal display device shown in FIG. 4, the front or back surface of the heater glass shown in FIG.

Next, the operation will be described. In a low-temperature environment, when electricity is supplied to the heating elements 31 and 32 via the electrodes 41 and 42, the heater glass sparsely surrounds the center of the liquid crystal cell 1,
The outer edge will be heated densely.

Therefore, the difference in the rate of temperature rise between the central portion and the outer edge of the liquid crystal cell 1 is small, and the temperature distribution can be made more uniform, and the difference in brightness between the central portion and the outer edge can be eliminated. The display quality can be improved.

FIG. 2 is a plan view of a heater glass constituting another embodiment of the present invention, (a) is a surface view thereof, and (b) is a plan view thereof.
Is a rear view.

2A and 2B, the heater glass 2 is composed of a glass substrate 20, and heating elements 33 and 34 and electrodes 43 and 44 formed on both surfaces of the glass substrate 20. .

Reference numeral 21 denotes an effective display area of the heater glass 2 corresponding to the effective display area 11 of the liquid crystal cell 1 when the heater glass 2 is brought close to the liquid crystal cell 1. It is to be close to the outside of the display area 11.

In FIG. 2A, the heating element 33 is formed outside the effective display area 21 at the outer edge of the glass substrate 20. Further, since the heating element 33 does not affect the effective display area of the liquid crystal cell, its material does not need to be ITO, and can be selected by setting a resistance value, heat generation efficiency and the like.

The electrode 43 is made of a metal such as gold, for example.
The heating element 33 is formed on the heating element 33 so as to be able to conduct electricity.

In FIG. 2B, the heating element 34 is formed on the entire surface of the glass substrate 20 by, for example, ITO formed by vapor deposition or the like. The electrodes 44 are made of a metal such as gold, for example, and are arranged and formed at both ends in the longitudinal direction of the glass substrate 20.

Then, similarly to the liquid crystal display device shown in FIG. 4, the front surface or the back surface of the heater glass 2 shown in FIG.

Next, the operation will be described. In a low-temperature environment, when electricity is supplied to the heating elements 33 and 34 via the electrodes 43 and 44, the entire surface of the heater glass 2 is heated by the heating element 34, and the effective display area 21 is
Is heated more heavily.

The entire liquid crystal cell 1 is heated by the heater glass 2 and the outside of the effective display area 11 is more heavily heated.
As a result, the difference in the rate of temperature rise between the center and the outer edge of the liquid crystal cell 1 is small, and the temperature distribution can be made uniform.

Accordingly, it is possible to eliminate the difference in luminance between the central portion and the outer edge portion of the liquid crystal cell 1, and to improve the display quality.

FIG. 3A is a sectional view of a main part showing the structure of another embodiment of the present invention, and FIG. 3B is a top view of FIG. 3A.

In FIG. 3A, the liquid crystal display device comprises a liquid crystal cell 1, a heater glass 2, and a mask 6 which covers the outside of the effective display area 11 of the liquid crystal cell 1.

In the heater glass 2, a transparent conductive film 3 as a heating element is vapor-deposited on one surface of a glass substrate 20, and an electrode 4 (for example, gold or the like) for supplying electricity to the transparent conductive film 3 is provided at an end thereof. It is configured.

A heater glass 2 is provided on one surface of the liquid crystal cell 1.
The surface opposite to the surface on which the transparent conductive film 3 is formed is close to the surface, and a heating element 35 is formed on the other surface so as to be arranged outside the effective display area 11. FIG. 3 (b)
In the figure, the central portion of the liquid crystal cell 1 is the effective display area 11, and the heating element 35 is formed outside the effective display area 11 at the outer edge of the liquid crystal cell 1.

In this case, the heating element 35 is placed in the effective display area 11
It does not need to be ITO, so that the degree of freedom in selecting its material and shape is increased. Then, for example, a film heater, a lead wire, a heater wire, a nichrome wire, or the like can be selected according to the setting of the resistance value, the heat generation efficiency, and the like.

The heating element 35 includes the mask 6 and the liquid crystal cell 1.
And may not necessarily be formed on the liquid crystal cell 1.

Next, the operation will be described. When a current is passed to the transparent conductive film 3 through the electrode 4 in a low-temperature environment, the entire heater glass 2 is heated by the transparent conductive film 3 and the entire surface of the adjacent liquid crystal cell 1 is heated.

Then, by energizing the heating element 35, the outer edge of the liquid crystal cell 1 outside the effective display area 11 is directly heated.

As a result, the difference in the rate of temperature rise between the center and the outer edge of the liquid crystal cell 1 is small, the temperature distribution is uniform, and the display quality is improved by eliminating the difference in brightness between the center and the outer edge. Can be improved.

The ratio of the electric power to be applied to the transparent conductive film 3 and the heating element 35 is determined by adjusting the resistances thereof by experiments so that the display quality improving effect is enhanced.

[0043]

As described above, according to the present invention, in a low-temperature environment, a difference in luminance such as "white spots" occurs between the center and the outer edge of the liquid crystal by uniformly raising the temperature of the liquid crystal cell. And a liquid crystal display device with improved display quality can be realized.

[Brief description of the drawings]

FIG. 1 is a plan view of a heater glass constituting one embodiment of the present invention.

FIG. 2 is a plan view of a heater glass constituting another embodiment of the present invention.

FIG. 3 is a configuration diagram showing another embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a conventional liquid crystal display device to which a heater is added.

FIG. 5 is a plan view of a heater glass included in a conventional liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal cell 2 Heater glass 3 Transparent conductive film 4, 41-44 Electrode 6 Mask 11 Effective display area 20 Glass substrate 21 Effective display area equivalent part 31-35 Heating element

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 GA63 HA06 HA14 MA04 NA01 NA30 PA01 2H093 NC76 ND02 ND09 ND45 NE01 3K034 AA02 AA03 AA15 AA16 AA29 AA35 BB05 BC25 BC28 CA02 CA17 CA32 JA01 JA10 3K092 PP20 QB03 Q20B RF12 RF17 RF23 VV22 5G435 AA12 BB12 GG21

Claims (6)

[Claims] 1. A liquid crystal display device having a liquid crystal cell sandwiching a liquid crystal between two substrates and a heater glass for heating the liquid crystal cell, wherein one surface and the other surface of the heater glass are different from each other. A liquid crystal display device comprising a pattern of heating elements. 2. The liquid crystal display device according to claim 1, wherein the heating element is formed in a stripe shape so as to form a grid on one surface and the other surface of the heater glass. 3. The liquid crystal display device according to claim 2, wherein the striped heating element is formed so that a central portion of the heater glass is sparse and a peripheral portion thereof is dense. 4. The liquid crystal display device according to claim 2, wherein the striped heating elements formed on one surface and the other surface of the heater glass are electrically connected to each other. 5. A liquid crystal display device having a liquid crystal cell sandwiching liquid crystal between two substrates and a heater glass for heating the liquid crystal cell, wherein one surface of the heater glass heats the entire surface of the liquid crystal cell. A liquid crystal display device, comprising: a heating element; and a heating element for heating the outside of the effective display area of the liquid crystal cell on the other surface. 6. A liquid crystal display device having a liquid crystal cell sandwiching a liquid crystal between two substrates, and a heater glass for heating the liquid crystal cell, wherein the liquid crystal cell has a surface which is not close to the heater glass. A liquid crystal display device comprising a heating element that heats an area outside an effective display area of a liquid crystal cell.