Liquid crystal display device with heater

• US 8,488,096 B2
• Filed: 03/16/2012
• Issued: 07/16/2013
• Est. Priority Date: 08/07/2008
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Aoki, Naoyuki
• Primary Examiner(s): Nguyen, Lauren
• Application Number:
  US13/422,655
• Publication Number:
  US 20120176569A1
• Time in Patent Office: 487 Days
• Field of Search: 349/72, 349/161, 361/514, 361/676
• US Class Current: 349/161
• CPC Class Codes: G02B 7/008 with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation
• CPC Class Codes: G02F 1/133 Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements arrangements or circuits for control of liquid crystal elements in a matrix, not structurally associated with these elements G09G3/36
• CPC Class Codes: G02F 1/133382 Heating or cooling of liquid crystal cells other than for activation, e.g. circuits or arrangements for temperature control, stabilisation or uniform distribution over the cell
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G03B 21/16 Cooling; Preventing overheating
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A liquid crystal display device includes a panel, a heater, and a temperature detector. The panel includes substrates, electrodes and liquid crystal. The electrodes and the liquid crystal are disposed between the substrates. The heater has a transparent heating member, and the heating member emits heat by being supplied with electricity. At least a part of the heating member of the heater is located to overlap with a display area of the panel in a thickness direction of the substrates. A temperature detecting portion of the temperature detector and the heating member of the heater are located adjacent to each other.

Claims

1. A liquid crystal display device comprising:

a liquid crystal display panel including

a first substrate and a second substrate opposing to the first substrate, a plurality of electrodes disposed between the first substrate and the second substrate, and

liquid crystal sealed between the first substrate and the second substrate, wherein the liquid crystal display panel has a display area and an outside area which is directly outside of the display area;

a heater having a transparent heating member disposed opposite to the electrodes through the first substrate, the heating member emitting heat by being supplied with electricity, the heating member being arranged to oppose the liquid crystal display panel, the heater including a first heater connector and a second heater connector which supply electricity to the to the heating member, and wherein the heating member is located in both the display area and the outside area of the liquid crystal display panel; and

a temperature detector having a temperature detecting portion, wherein

at least a part of the heating member is located to overlap with the display area of the liquid crystal display panel in a thickness direction of the substrates,

the temperature detecting portion of the temperature detector and the heating member of the heater are located adjacent to each other, and

the heating member has a plurality of resistance adjusting portions that increase a resistance of portions of the heating member to limit current flowing through the heating member located in the display area or current flowing adjacent to the temperature detector, the plurality of resistance adjusting portions being located to oppose the liquid crystal display panel, the plurality of resistance adjusting portions being located between the first connector and the second connector of the heater, wherein the plurality of resistance adjusting portions are located only in the outside area, and wherein the plurality of resistance adjusting portions narrow a physical path for current to flow through the heating member, to thereby reduce an amount of heat emitted by a portion of the heating member.

2. The liquid crystal display device according to claim 1, wherein the heater further has a supporting board for supporting the heating member, and the temperature detector is disposed on the heating member through the supporting board.

3. The liquid crystal display device according to claim 2, further including

a compensating panel disposed adjacent to the first substrate of the liquid crystal display panel, wherein

the compensating panel has

a third substrate opposing to the liquid crystal display panel,

a fourth substrate located opposite to the liquid crystal display panel through the third substrate, and

liquid crystal sealed between the third substrate and the fourth substrate,

the supporting board of the heater is the third substrate of the compensating panel.

4. The liquid crystal display device according to claim 1, wherein the heating member is disposed on a face of the first substrate opposite from the electrodes, and the temperature detector is disposed on the heating member opposite from the electrodes.

5. The liquid crystal display device according to claim 1, wherein the heating member is further located outside of the display area of the liquid crystal display panel in the thickness direction of the substrates, and the temperature detector is disposed adjacent to the heating member located outside of the display area.

6. The liquid crystal display device according to claim 1, wherein the heating member covers at least entire face of the display area.

7. The liquid crystal display device according to claim 1, wherein the resistance adjusting portions increase a resistance of portions of the heating member by removing a part of the heating member.

8. The liquid crystal display device according to claim 1, wherein the heating member is further located outside of the display area of the liquid crystal display panel in the thickness direction of the substrates, and the resistance adjusting portions increase a resistance of the heating member by removing a part of the heating member located outside of the display area.

9. The liquid crystal display device according to claim 1, further comprising a temperature fuse located adjacent to the heating member, wherein the temperature fuse is connected to the heating member in series.

10. The liquid crystal display device according to claim 1, wherein the temperature detector is a thermistor.

11. The liquid crystal display device according to claim 1, wherein the temperature detector is located in the outside area of the liquid crystal display panel.

12. The liquid crystal display device according to claim 1, wherein the plurality of resistance adjusting portions comprise a plurality of apertures that are formed through the material of the heating member.

13. The liquid crystal display device according to claim 1, further comprising a flexible print board that is connected to the first connector and the second connector.

14. The liquid crystal display device according to claim 13, wherein the temperature detector is directly fixed to a surface of the flexible print board.