JP2003015148A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device which has no danger of an increase in manufacturing costs of a flexible wiring board, and is also capable of adjusting a driving voltage according to a temperature of liquid crystal display elements. SOLUTION: A temperature detecting element 31 detects a temperature of the liquid crystal display elements 20. The flexible wiring board 28 comprises a 1st wiring pattern 35 provided on a 1st surface and connected with the liquid crystal display elements 20, and a 2nd wiring pattern 36 provided on the 1st surface and connected with the temperature detecting element 31. A driving voltage adjusting means adjusts a driving voltage based on a temperature data outputted from the temperature detecting element 31. The flexible wiring board 28 is provided with a mount part 30 which is mounted with the temperature detecting element 31 on the 1st surface and curved, and of which the 2nd surface is bonded to the liquid crystal display elements 20. The mount part 30 is provided with an opening part 37, and the 2nd surface is bonded to the liquid crystal display elements 20 by the opening part.

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 which adjusts a drive voltage based on temperature data output from a temperature detecting element.

[0002]

2. Description of the Related Art Conventionally, there is a liquid crystal display device 2 using a liquid crystal display element 1 as shown in FIG. The liquid crystal display element 1 is formed by bonding a polarizing plate (not shown) to a liquid crystal cell in which liquid crystal is sealed in a pair of transparent substrates 3 and 4 on which transparent electrode films are formed. A drive circuit 5 that drives the liquid crystal display element 1 is mounted. Further, one end of a flexible wiring board 6 is connected to the liquid crystal display element 1, and a hard wiring board 7 is connected to the other end of the flexible wiring board 6. A microcomputer 8 for controlling the liquid crystal display element 1 is mounted on the hard wiring board 7.

The liquid crystal display element 1 is a non-emission type display element, and a backlight means 9 is provided to illuminate the liquid crystal display element 1 so that good visibility can be obtained. The backlight means 9 is a light emitting element 1 such as a cold cathode tube.
0, the light guide member 11 and the reflection members 12 and 13. The liquid crystal display element 1 is a negative display type and is a segment to which a drive voltage is applied (hereinafter referred to as an on-segment).
A desired character or figure is displayed by increasing the transmittance of the.

[0004]

However, there is a problem that the contrast ratio is lowered when the temperature of the liquid crystal display element 1 changes. That is, when the temperature of the liquid crystal display element 1 becomes low, the transmittance of the on-segment decreases, and the contrast ratio decreases. Further, when the temperature of the liquid crystal display element rises, the transmittance of the segment (off segment) to which the driving voltage is not applied and the background region increases, and the contrast ratio decreases. Therefore, it can be considered that the temperature detecting element 14 is bonded to the liquid crystal display element 1 and the drive voltage is adjusted based on the temperature data output from the temperature detecting element 14. However, not only the lead wire 15 for connecting the temperature detection element 14 and the hard wiring board 7 is required, but the number of parts is increased, and one end of the lead wire 15 is connected to the temperature detection element 14 and the other end is hard wiring. Since it had to be connected to the plate 7, there was a problem that assembly was complicated.

In order to solve this problem, a mounting portion 16 is provided on the flexible wiring board 6 as shown in FIG.
It is conceivable to mount the temperature detecting element 14 on the No. 6 unit. However, the wiring pattern 1 is formed on both sides of the flexible wiring board 6.
Since 7 and 18 have to be formed, there is a problem that the manufacturing cost of the flexible wiring board 6 becomes high. That is, the first wiring pattern 1 to which the liquid crystal display element 1 is connected
Since 7 must be formed on the front surface of the flexible wiring board 6 and the second wiring pattern 18 to which the temperature detecting element 14 is connected must be formed on the back surface, the manufacturing cost of the flexible wiring board 6 increases. . The present invention has been made in view of this problem, and there is no concern that the manufacturing cost of the flexible wiring board will increase, and the drive voltage can be adjusted according to the temperature of the liquid crystal display element. Is provided.

[0006]

According to the present invention, in order to solve the above problems, a liquid crystal display element 20 and a liquid crystal display element 2 are provided.
A temperature detection element 31 that detects a temperature of 0 and outputs temperature data for adjusting a drive voltage, and a first wiring pattern 3 that is provided on the first surface and is connected to the liquid crystal display element 20.
5 and a flexible wiring board 28 having a second wiring pattern 36 provided on the first surface and to which the temperature detecting element 31 is connected, the liquid crystal display device having the first surface. The flexible wiring board 28 is provided with a mounting portion 30 on which the temperature detecting element 31 is mounted, is bent, and has the second surface bonded to the liquid crystal display element 20.

Further, according to the present invention, the mounting portion 30 is provided with an opening 37, and the second surface is bonded to the liquid crystal display element 20 through the opening 37.

[0008]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings. Reference numeral 20 denotes a liquid crystal display element, and the liquid crystal display element 20 includes a pair of translucent substrates 21 and 2.
Polarizing plates (not shown) are attached to both front and rear surfaces of a liquid crystal cell in which liquid crystal is sealed in 2. Reference numeral 23 is a drive circuit, and the drive circuit 23 is mounted on the transparent substrate 22. A light emitting diode 24 is mounted on the hard wiring board 25. Reference numeral 26 denotes a light diffusing plate, which is disposed between the liquid crystal display element 20 and the hard wiring board 25 and diffuses the light emitted from the light emitting diode 24 so that the liquid crystal display element 20 has a uniform brightness. To

Reference numeral 27 denotes a case body, and this case body 27
A liquid crystal display element 20, a hard wiring board 25, and a light diffusing plate 26.
Is assembled. Reference numeral 28 denotes a flexible wiring board. One end of the flexible wiring board 28 is connected to the liquid crystal display element 20 by an anisotropic conductive film (not shown), and the other end is connected to the hard circuit board 25. Has been done. The flexible wiring board 28 includes a strip-shaped base portion 29 and the mounting portion 3 drawn out from the base portion 29.
It consists of 0. Reference numeral 31 is a temperature detecting element such as a thermistor. The temperature detecting element 31 is a flexible wiring board 28.
It is mounted on the mounting portion 30 of the. For the hard circuit board 25,
The liquid crystal display element 2 is formed with a predetermined wiring pattern.
A microcomputer 32 for controlling 0 is provided.

FIG. 3 is a block diagram of a liquid crystal display device.
The temperature detecting element 31 detects the temperature of the liquid crystal display element 20 and outputs temperature data to the microcomputer 32. Reference numeral 33 is a drive voltage adjusting means composed of the microcomputer 32 and the drive circuit 23, and adjusts the drive voltage based on the temperature data output from the temperature detecting element 31. The light emitting diode 24 is driven to be turned on by the microcomputer 32 via the lighting circuit 34. The lighting circuit 34 is composed of a PWM circuit, an inverter circuit, and the like.

Next, the flexible wiring board 28 will be described in detail with reference to FIGS. 1, 4 and 5. 1 and 4
Then, the back surface of the flexible wiring board 28 is illustrated. The flexible wiring board 28 includes a first wiring pattern 35 and a second wiring pattern 36 made of copper foil on a substrate made of polyimide.
Is formed. The first wiring pattern 35 connects the liquid crystal display element 20 and the hard wiring board 25, and the second wiring pattern 36 connects the temperature detection element 31 and the hard wiring board 25. The first wiring pattern 35 and the second wiring pattern 36 are the flexible wiring board 2
8 is formed on the surface (first surface). The mounting portion 30 is provided with a rectangular opening 37, and the mounting portion 30 is
The back surface (second surface) is bent and adhered to the liquid crystal display element 20 at the opening 37.

According to this embodiment, the drive voltage can be adjusted based on the temperature data output from the temperature detecting element 20, and an appropriate contrast ratio can be obtained.
In addition, the flexible wiring board 28 having the wiring patterns 35 and 36 provided on only one surface (that is, the front surface) is used for the liquid crystal display element 2
0 and the hard wiring board 25 can be connected to each other, and the temperature detecting element 31 and the hard wiring board 25 can be connected to each other. Therefore, it is possible to use a flexible wiring board 28 having wiring patterns formed on both surfaces as in the conventional case. Therefore, there is no fear that the manufacturing cost of the flexible wiring board 28 will increase.

[0013]

The present invention provides a liquid crystal display element, a temperature detection element for detecting temperature of the liquid crystal display element and outputting temperature data for adjusting a driving voltage, and the liquid crystal display provided on the first surface. A liquid crystal display device comprising: a flexible wiring board having a first wiring pattern to which elements are connected and a second wiring pattern provided on the first surface and to which the temperature detecting element is connected, The flexible wiring board is provided with a mounting portion on which the temperature detecting element is mounted on the first surface and bent, and the second surface is bonded to the liquid crystal display element. It is possible to adjust the drive voltage according to the temperature of the liquid crystal display element without fear of increasing the manufacturing cost of the plate.

[Brief description of drawings]

FIG. 1 is an enlarged view of essential parts showing an embodiment of the present invention.

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

FIG. 3 is a block diagram showing the embodiment.

FIG. 4 is an enlarged view of a main part of a flexible wiring board showing the embodiment.

FIG. 5 is an enlarged cross-sectional view of a main part of a flexible wiring board showing the embodiment.

FIG. 6 is a cross-sectional view of a liquid crystal display device showing a conventional example.

FIG. 7 is an enlarged view of a main part showing another conventional example.

[Explanation of symbols]

20 Liquid crystal display element 28 flexible wiring board 28 30 mounting part 31 Temperature detection element 33 Drive voltage adjusting means 35 First wiring pattern 36 Second wiring pattern 37 opening

Continued front page    F term (reference) 2H089 HA17 KA17 QA06 QA13 TA01                       TA03 TA07 TA18                 2H092 GA50 GA55 GA61 MA31 NA25                       PA01 PA06 PA13                 2H093 NC02 NC50 NC57 NC63 ND02                       ND49 NE01 NE06 NE07 NE10                 5G435 AA00 AA12 BB12 EE33 EE37                       EE47 FF06 GG21

Claims (2)

[Claims] 1. A liquid crystal display element, a temperature detection element for detecting temperature of the liquid crystal display element and outputting temperature data for adjusting a drive voltage, and a liquid crystal display element provided on a first surface and connected to the liquid crystal display element. A flexible wiring board having a first wiring pattern having a first wiring pattern and a second wiring pattern provided on the first surface and to which the temperature detection element is connected, The liquid crystal display device, wherein the flexible wiring board is provided with a mounting portion on which the temperature detecting element is mounted, is bent, and the second surface is bonded to the liquid crystal display element. 2. The liquid crystal display device according to claim 1, wherein an opening is provided in the mounting portion, and the second surface is bonded to the liquid crystal display element through the opening. .