JP2001215473A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a liquid crystal display device with a reduced cost by simplifying the construction of components and the manufacturing process. SOLUTION: The liquid crystal display device having a liquid crystal cell holding a liquid crystal between two substrates and a heater glass with heat generators to heat the liquid crystal cell formed on its both surfaces is characterized by that the heat generators are formed with materials different from each other in one surface and the other surface 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 an exploded perspective view of a conventional liquid crystal display device to which a heater is added, which is disclosed in, for example, JP-A-59-228290. In FIG. 2, the liquid crystal display device includes a liquid crystal cell 1 and a heater glass 2.

[0005] A liquid crystal cell 1 is filled with liquid crystal between two glass substrates, and a heater glass 2 is brought close to one surface thereof. The central portion of the liquid crystal cell 1 is an effective display area A where the display is effective.

FIG. 3 is a plan view of a conventional heater glass, in which (a) is a front view and (b) is a rear view. FIG.
1A, for example, an indium tin oxide film (hereinafter referred to as an ITO film) 3 is vapor-deposited on one surface of a heater glass 2 as a transparent conductive film that generates heat when energized, and electrodes are provided on both ends thereof. 4 and 5 are formed, for example, by printing a silver paste. Then, input lead wires 6 and 7 for supplying electric power from the outside are fixed to the electrodes by silver paste.

In FIG. 3 (b), an ITO film 8 is deposited on the other surface of the heater glass 2 outside the effective display area equivalent portion A 'of the heater glass (outer edge of the heater glass). The contact electrodes 9 and 10 that are patterned by etching the film and are electrically connected to the electrodes 4 and 5 are printed on a silver paste to form the IT.
It is formed on the O film 8.

Then, the effective display area equivalent portion A 'where the ITO film 8 is not formed is brought close to the liquid crystal cell 1, and in a low temperature environment, the ITO film 3 and the I
By energizing the TO film 8 to heat the heater glass 2 and heating the liquid crystal cell 1 with the heat, the operation of the liquid crystal display device is ensured.

In this case, the ITO film 3 heats the entire surface of the liquid crystal cell 1. However, in a low temperature environment, the temperature of the outer edge of the liquid crystal cell 1 is more likely to be lower than that of the center portion.
In this method, the temperature of the liquid crystal cell 1 is uniformly increased by auxiliary heating of the outer edge of the screen, and the liquid crystal display quality is improved.

[0008]

However, such a liquid crystal display device has the following problems. ITO film 8
Is intended to correct the temperature of the central portion and the outer peripheral portion of the liquid crystal cell. Therefore, the resistance values of the ITO film 2 and the ITO film 8 simulate the amount of heat such that the temperature over the entire liquid crystal cell 1 becomes uniform. And the resistance values of the two are different as a result. The main control conditions that are important when depositing ITO on a glass substrate by vapor deposition are the resistance value and the transmittance of light, but the transmittance decreases when the resistance value decreases (when the ITO film thickness increases). In terms of manufacturing, it is difficult to properly manage these conditions. ITO film 8
Is patterned by etching after depositing an ITO film on the entire surface. However, it is difficult to adjust the resistance value after patterning because the resistance value of the ITO film deposited on the entire surface is affected by variations in the resistance value. Since it is necessary to deposit expensive ITO on both sides of the glass substrate, the cost increases. There are many processing steps such as printing and etching of ITO and silver paste, and the cost is high.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and maintains the function of improving display quality under a low-temperature environment, and simplifies the manufacturing process by using inexpensive materials. An object is to realize a liquid crystal display device with reduced cost.

[0010]

According to a first aspect of the present invention, a liquid crystal cell sandwiching a liquid crystal between two substrates and a heater glass having heating elements formed on both sides thereof for heating the liquid crystal cell are provided. In the liquid crystal display device having the heating element,
A liquid crystal display device characterized in that one surface and the other surface of the heater glass are formed of different materials.

According to a second aspect of the present invention, a first heating element for heating the entire surface of the liquid crystal cell is formed on one surface of the heater glass, and an outside of an effective display area of the liquid crystal cell is formed on the other surface. 2. The liquid crystal display device according to claim 1, wherein a second heating element to be heated is formed.

According to a third aspect of the present invention, in the liquid crystal display device according to the second aspect, the first heating element and the second heating element are electrically connected.

According to a fourth aspect of the present invention, in the liquid crystal display device according to the second or third aspect, the first heating element is a transparent conductive film.

According to a fifth aspect of the present invention, in the liquid crystal display device according to the fourth aspect, the transparent conductive film is made of indium tin oxide (ITO).

According to a sixth aspect of the present invention, the second heating element is made of a silver paste.
And a liquid crystal display device according to claim 3.

According to a seventh aspect of the present invention, in the liquid crystal display device according to the sixth aspect, the surface shape of the silver paste is corrugated.

The liquid crystal display device according to claim 7, wherein the resistance value of the silver paste is adjusted to a desired resistance value by changing the shape of the waveform. .

[0018]

Next, embodiments of the present invention will be described with reference to the drawings. In the following drawings, FIG.
3 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. 1A and 1B are plan views of a heater glass constituting an embodiment of the present invention, wherein FIG. 1A is a front view and FIG. 1B is a rear view.

In FIG. 1 (a), similarly to FIG. 3 (a), one side of the heater glass 2 is provided as a first heating element as a first heating element.
A TO film 3 is deposited on the entire surface, and electrodes 4 and 5 are provided on both ends thereof.
It is formed by etching the printed silver paste.

In FIG. 1B, a silver paste 11 as a second heating element is printed on the other surface of the heater glass 2 outside the effective display area equivalent portion A '(outer edge of the heater glass) of the heater glass. , And at the same time silver paste 1
Part 1 is formed as contact electrodes 9 and 10 so as to be electrically connected to the electrode 4. The shape of the silver paste 11 has a waveform 12 as shown in an enlarged view of a main part in FIG.

In this case, since the resistance value of the silver paste 11 is determined in advance, the length (wavelength or amplitude of the waveform 12) and width (the line width of the waveform 12;
By adjusting the line thickness) and the height (thickness of the waveform 12), it is possible to stably obtain a desired resistance value of the second heating element.

The resistance value of the second heating element can be modified by forming a silver paste 11 and then overcoating the waveform 12 with a new silver paste.

In addition, the conventional steps of ITO vapor deposition and etching can be omitted, and the second heating element made of an inexpensive silver paste is replaced with the same step as that of forming the contact electrodes 9 and 10 made of the conventional silver paste. Since they are formed in steps, the total number of steps can be reduced, and the cost can be reduced.

[0024]

As described above, according to the present invention, the second heating element for heating the area outside the effective display area of the liquid crystal cell is formed by printing an inexpensive silver paste in a waveform. The manufacturing process can be simplified, and a liquid crystal display device with reduced cost can be realized.

[Brief description of the drawings]

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

FIG. 2 is an exploded perspective view of a conventional liquid crystal display device to which a heater is added.

FIG. 3 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 ITO film 4,5 Electrode 6,7 Lead wire 9,10 Contact electrode 11 Silver paste A Effective display area A 'Effective display area equivalent part

Claims (8)

[Claims] 1. A liquid crystal display device comprising: a liquid crystal cell sandwiching a liquid crystal between two substrates; and a heater glass having heating elements formed on both sides thereof for heating the liquid crystal cell. A liquid crystal display device, wherein one surface and another surface of glass are formed of different materials. 2. A heating element for heating the entire surface of the liquid crystal cell on one side of the heater glass, and a second heating element for heating the outside of the effective display area of the liquid crystal cell on the other side. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is formed. 3. The liquid crystal display device according to claim 2, wherein said first heating element and said second heating element are electrically connected. 4. The liquid crystal display device according to claim 2, wherein said first heating element is a transparent conductive film. 5. The transparent conductive film is made of indium tin oxide (I
5. The liquid crystal display device according to claim 4, wherein the liquid crystal display device is (TO). 6. The liquid crystal display device according to claim 2, wherein said second heating element is made of silver paste. 7. The liquid crystal display device according to claim 6, wherein the surface shape of the silver paste is corrugated. 8. The liquid crystal display device according to claim 7, wherein a resistance value of said silver paste is adjusted to a desired resistance value by changing a shape of said waveform.