JP2001337313A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the responsiveness from lowering due to a heightened coefficient of viscosity of a liquid crystal and to prevent display brightness from lowering in the case a liquid crystal display device is used in a cold place. SOLUTION: The liquid crystal cell 16 is provided with a specified display region S. A heating member 32 warms the liquid crystal cell 16. The heating member 32 is arranged so as to be in contact with the liquid crystal cell 16 outside the display region S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having a heater for heating a liquid crystal display element.

[0002]

2. Description of the Related Art Conventionally, there is a liquid crystal display device using a liquid crystal display element 1 as shown in FIG. The liquid crystal display element 1 is obtained by bonding polarizing plates 4 and 5 to the front and rear surfaces of a liquid crystal cell 3 in which liquid crystal is sealed in a pair of translucent substrates 2 provided with a transparent electrode film. A tape carrier package 6 (hereinafter, referred to as TCP) is connected to the liquid crystal display element 1. This TCP 6 has a flexible wiring board 7 and a liquid crystal display element 1.
Is provided with a drive circuit 8 for driving the. TCP6
Is connected to a hard wiring board 9.
Is provided with a microcomputer 10 for controlling the drive circuit 8.

The liquid crystal display element 1 is a light receiving type display element which cannot emit light by itself, and is a light source 11 such as a cold cathode tube.
To illuminate the liquid crystal display element 1 so that good visibility can be obtained. A light guide member 12 and a reflection member 13 are provided behind the liquid crystal display element 1,
Light from the light source 11 is reflected by the reflection member 13 to the liquid crystal display element 1 side. On the rear surface side of the liquid crystal display element 1, a translucent sheet heater 14 is provided. The translucent sheet heater 14 warms the liquid crystal display element 1 when the liquid crystal display device is used in a cold place. That is, when the temperature of the liquid crystal display element 1 is low, the viscosity coefficient of the liquid crystal increases and the responsiveness decreases. However, the liquid crystal display element 1 is heated by the translucent sheet heater 14 so that the desired responsiveness can be obtained. , The temperature of the liquid crystal display element 1 is controlled.

[0004]

However, when the translucent sheet heater 14 is used, there is a problem that the display luminance is slightly lowered. That is, the translucent sheet heater 14
Has a transmittance of about 85%, and the translucent sheet heater 14
The display brightness is reduced by about 15% as compared with the case where is not used. The present invention has been made in view of this problem, and a liquid crystal display device that can prevent a decrease in responsiveness and a decrease in display luminance while increasing the viscosity coefficient of liquid crystal when used in a cold place. Is provided.

[0005]

According to the present invention, there is provided a liquid crystal display element having a predetermined display area, wherein
5, a liquid crystal display device comprising: heating members 32, 43 for warming the liquid crystal display elements 15, 38; and a case body 31 accommodating the liquid crystal display elements 15, 38 and the heating members 32, 43. And the heating members 32, 43
Is the liquid crystal display element 1 outside the display area S.
5 and 38 are provided so as to be in contact therewith.

The present invention also relates to the liquid crystal display element 15,
A light source 28 disposed behind the light source 38 and illuminating the liquid crystal display elements 15 and 38 is provided.

The present invention also relates to the liquid crystal display element 15.
Has a first liquid crystal cell 16 having the display area S, and a second liquid crystal cell 17 disposed so as to overlap the first liquid crystal cell 16, and the heating member 32 It is arranged between a first liquid crystal cell 16 and the second liquid crystal cell 17.

Further, the present invention provides a heat insulating member 46 that makes it difficult for the heat generated by the heating member 43 to be transmitted to the case body 31.
Is provided.

According to the present invention, the heating member 43 is pressed and held by the liquid crystal display element 38 by the heat insulating member 46.

Further, the present invention has a control means 36 for turning on / off the heating members 32 and 43 based on the temperature detected by the temperature detecting means 29.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. 1 to 3 are views showing a first embodiment.

Reference numeral 15 denotes a liquid crystal display element. The liquid crystal display element 15 includes a liquid crystal cell 16 (first liquid crystal cell), a liquid crystal cell 17 (second liquid crystal cell), and polarizing plates 18 and 19. . The polarizing plate 18 is attached to the front surface of the liquid crystal cell 16, and the polarizing plate 19 is attached to the rear surface of the liquid crystal cell 17. The liquid crystal cell 16 is formed by enclosing liquid crystal in a pair of translucent substrates 20 on which transparent electrodes are formed. The liquid crystal cell 16 is of the STN (super twisted nematic) type, and the liquid crystal display element 13 has a rectangular display area S in which a large number of pixels P are arranged in a matrix.

The liquid crystal cell 17 has a pair of translucent substrates 21 filled with liquid crystal, and is disposed behind the liquid crystal cell 16. The liquid crystal cell 17 is an interference cell that adjusts a display color tone of the liquid crystal display element 15. The polarizing plates 18 and 19 are
It is sufficient that the size is at least larger than the display area S. However, in order to prevent light leakage, the size is desirably substantially the same as the front surface of the liquid crystal cell 16 or the rear surface of the liquid crystal cell 17.

Reference numeral 23 denotes a TCP. The TCP 23 has a structure in which a driving circuit 25 is provided on a flexible wiring board 24.
One end of the flexible wiring board 24 is connected to the liquid crystal cell 16 by an anisotropic conductive film (not shown). Reference numeral 26 denotes a hard wiring board, on which a microcomputer 27 for controlling the drive circuit 25 is provided. The other end of the flexible wiring board 24 is connected to the hard wiring board 26. 28
Is a light emitting diode (light source). The light emitting diode 28 is provided on the front surface of the hard wiring board 26 and illuminates the liquid crystal display element 15 from behind.

Reference numeral 29 denotes a temperature sensor (temperature detecting means). The temperature sensor 29 is provided on the rear surface of the hard wiring board 26. Reference numeral 30 denotes a light diffusing plate.
Is disposed between the liquid crystal display element 15 and the light emitting diode 28. Reference numeral 31 denotes a case body.
The liquid crystal display element 15, the light diffusion plate 30, and the hard wiring board 26 are assembled to the liquid crystal display element 15. An opening 31a is provided in the case body 31, and the opening 31a is a rectangle slightly larger than the display area S of the liquid crystal cell 16.

A heater (heating member) 32 is disposed between the liquid crystal cell 16 and the liquid crystal cell 17. The heater 32 is formed by coating a thin stainless steel plate 33 with a translucent resin 34 such as polyimide.
The heater 32 has a substantially U-shape.
6 is provided on the periphery. The heater 32 is adhered to the rear surface of the liquid crystal cell 16 with an adhesive tape (not shown) so as to contact the liquid crystal cell 16 outside the display area S. The stainless steel plate 33 has a meandering shape and is connected to the heater circuit 35.

FIG. 3 is a block diagram for explaining the control means 36 for turning on / off the heater 32. A power supply circuit 37 adjusts the voltage of a battery (or commercial power supply) and supplies power to the microcomputer 27 and the heater circuit 31. The control means 36 is a microcomputer 27
And a heater circuit 31. The heater 32 is turned on when the temperature detected by the temperature sensor 29 becomes 0 ° C. or lower, and turned off when the temperature becomes 5 ° C. or higher.

FIGS. 4 and 5 show a second embodiment. The same portions as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Reference numeral 38 denotes a liquid crystal display element. The liquid crystal display element 38 includes a liquid crystal cell 39 and polarizing plates 40 and 41.
It consists of The liquid crystal cell 39 is formed by enclosing liquid crystal in a pair of translucent substrates 42, and includes polarizing plates 40 and 41.
Are attached to the front and rear surfaces of the liquid crystal cell 39, respectively.
The liquid crystal cell 39 is of the STN type, and has a rectangular display area S in which many pixels P are arranged in a matrix.

The heater 43 is formed by coating a thin stainless steel plate 44 with a transparent resin 45. The heater 43 has a substantially U-shape, and the liquid crystal cell 3 is disposed outside the display area S.
9 so as to be in contact with the front surface. Reference numeral 46 denotes a heat insulating member. The heat insulating member 46 is disposed between the heater 43 and the case body 31 so that heat of the heater 43 is not transmitted to the case body 31. The heat insulating member 46 has substantially the same shape as the heater 43, and is provided on the periphery of the liquid crystal cell 39. The heater 43 is pressed and held by the liquid crystal display element 38 due to the elasticity of the heat insulating member 46.

According to each of the above embodiments, the heater 3
When the liquid crystal display device is used in a cold place, it is possible to prevent the viscosity of the liquid crystal in the liquid crystal cells 16 and 39 from being increased and the responsiveness from being lowered. There is no fear that the display luminance is reduced due to the above-described translucent sheet heater 14. The polarizing plates 18 and 1
Since heaters 9, 40 and 41 have low heat resistance, the heaters 32, 4
It is desirable to dispose them so as not to contact the third. When the second liquid crystal cell 17 (interference cell) is provided as in the first embodiment, the first liquid crystal cell 16 and the second liquid crystal cell 17 are provided.
It is desirable to dispose the heater 32 between them, so that the heater 32 does not contact the polarizing plates 18 and 19, and
It can be arranged as close to the display area S as possible.

[0021]

The present invention provides a liquid crystal display device having a liquid crystal display element having a predetermined display area, a heating member for warming the liquid crystal display element, and a case housing the liquid crystal display element and the heating member. Wherein the heating member comprises:
The liquid crystal display device is provided so as to be in contact with the liquid crystal display element outside the display region, and when the liquid crystal display device is used in a cold place, the viscosity coefficient of the liquid crystal in the liquid crystal cell is increased and the responsiveness is reduced. Can be prevented, and there is no fear that the display luminance is reduced.

Further, according to the present invention, the liquid crystal display element has a first liquid crystal cell having the display area, and a second liquid crystal cell disposed so as to overlap the first liquid crystal cell. The heating member is disposed between the first liquid crystal cell and the second liquid crystal cell, so that the heating member is not in contact with the polarizing plate, and as much as possible in the display area. Can be placed near.

[Brief description of the drawings]

FIG. 1 is a rear view of a liquid crystal cell and a heater according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the liquid crystal display device showing the embodiment.

FIG. 3 is a block diagram showing the embodiment.

FIG. 4 is a front view of a liquid crystal cell and a heater according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of the liquid crystal display device showing the embodiment.

FIG. 6 is a sectional view showing a conventional example.

[Explanation of symbols]

 Reference Signs List 15 liquid crystal display element 16 liquid crystal cell (first liquid crystal cell) 17 liquid crystal cell (second liquid crystal cell) 28 light emitting diode (light source) 29 temperature sensor (temperature detecting means) 31 case body 32 heater (heating member) 36 control means 38 liquid crystal display element 39 liquid crystal cell 43 heater (heating member)

Claims (7)

[Claims] 1. A liquid crystal display device comprising: a liquid crystal display element having a predetermined display area; a heating member for heating the liquid crystal display element; and a case housing the liquid crystal display element and the heating member. The liquid crystal display device, wherein the heating member is provided outside the display area. 2. The liquid crystal display device according to claim 1, further comprising a light source disposed behind said liquid crystal display element and illuminating said liquid crystal display element. 3. The liquid crystal display device according to claim 1, wherein the liquid crystal display element has a polarizing member,
The liquid crystal display device, wherein the heating member is arranged so as not to contact the polarizing member. 4. The liquid crystal display device according to claim 1, wherein the liquid crystal display element overlaps the first liquid crystal cell having the display area and the first liquid crystal cell. And a second liquid crystal cell disposed together, wherein the heating member is in contact with at least the first liquid crystal cell between the first liquid crystal cell and the second liquid crystal cell. A liquid crystal display element, which is disposed. 5. The liquid crystal display device according to claim 2, further comprising a heat insulating member for preventing heat generated by said heating member from being transmitted to said case body. apparatus. 6. The liquid crystal display device according to claim 5, wherein the heating member is pressed and held by the liquid crystal display element by the heat insulating member. 7. The liquid crystal display device according to claim 1, further comprising control means for turning on / off the heating member based on the temperature detected by the temperature detection means. Liquid crystal display.