LIQUID CRYSTAL DISPLAY DEVICE

• US 20080259252A1
• Filed: 04/16/2008
• Published: 10/23/2008
• Est. Priority Date: 04/20/2007
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Kaneko, Hiroki, Hiyama, Ikuo, TANAKA, Toshiaki
• Granted Patent: US 8,525,952 B2
• Time in Patent Office: Days
• US Class Current: 349/69
• CPC Class Codes: F21K 9/60 Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133612 Electrical details
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: H05B 45/397 Current mirror circuits
• CPC Class Codes: H05B 45/40 Details of LED load circuits
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

An illumination device using a plurality of LED light sources each of which is driven by a single power supply is provided to attain simple operational response and voltage control.

The illumination device includes a light source module, the module comprising: a substrate; a plurality of wiring lines provided on the substrate; and a plurality of LED devices implemented in the wiring lines; wherein the plurality of LED devices include a plurality of red LED devices, a plurality of green LED devices, and a plurality of blue LED devices; wherein the plurality of wiring lines include a wiring line having the plurality of red LED devices implemented in series, a wiring line having the plurality of green LED devices implemented in series, and a wiring line having the plurality of blue LED devices implemented in series; and wherein the plurality of wiring lines are connected in parallel and driven by a single power voltage.

Claims

1. An illumination device including a light source module, the module comprising:

a substrate;

a plurality of wiring lines provided on the substrate; and

a plurality of LED devices implemented in the wiring lines;

wherein the plurality of LED devices include a plurality of red LED devices, a plurality of green LED devices, and a plurality of blue LED devices;

wherein the plurality of wiring lines include a wiring line having the plurality of red LED devices implemented in series, a wiring line having the plurality of green LED devices implemented in series, and a wiring line having the plurality of blue LED devices implemented in series; and

wherein the plurality of wiring lines are connected in parallel and driven by a single power voltage.

2. The illumination device according to claim 1, wherein:

the LED devices provided in the light source module include n(R) red LED devices, n(G) green LED devices, and n(B) blue LED devices;

the red LED devices, the green LED devices, and the blue LED devices operate on voltages V(R), V(G), and V(B), respectively; and

a relation of n(R)≧

n(G)=n(B) or n(R)×

V(R)=n(G)×

V(G)=n(B)×

V(B) is satisfied.

3. The illumination device according to claim 1, wherein:

the plurality of LED devices provided in the light source module are implemented with a number ratio of 3;

2;

2 for red LED devices;

green LED devices;

blue LED devices.

4. The illumination device according to claim 1, wherein:

the illumination device includes a plurality of light source modules; and

each of the plurality of light source modules operates on the same power voltage.

5. The illumination device according to claim 1, wherein:

the illumination device includes a plurality of light source modules;

each of the plurality of light source modules operates on the same power voltage; and

the power voltage has a value of 6 mV (m is an integer).

6. The illumination device according to claim 5, wherein:

each of the plurality of light source modules is composed of six red LED devices, four green LED devices, and four blue LED devices; and

each of the plurality of light source modules operates on a 12V power voltage.

7. A liquid crystal display device including the illumination device according to claim 5 and a liquid crystal display panel which supplies light from the illumination device, wherein:

the plurality of light source modules are driven by the same voltage as a 12V power voltage for a timing controller circuit supplied from a power supply mounted on the liquid crystal display panel.

8. The liquid crystal display device according to claim 7, wherein:

each of the plurality of light source modules independently performs luminance control.

9. The illumination device according to claim 4, wherein:

each of the plurality of light source modules is composed of 12 red LED devices, eight green LED devices, and eight blue LED devices; and

each of the plurality of light source modules operates on a 24V power voltage.

10. A liquid crystal display device including the illumination device according to claim 9 and a liquid crystal display panel which receives light from the illumination device, wherein:

the plurality of light source modules are driven by a 24V power supply for AC-DC conversion mounted on the liquid crystal display panel.

11. The liquid crystal display device according to claim 10, wherein:

each of the plurality of light source modules independently performs luminance control.

12. A liquid crystal display device according to claim 3, wherein:

each of the plurality of light source modules is driven by a constant-voltage power supply having a 12V or 24V power voltage;

at least one zener diode is mounted in each of the red LED device wiring line, the green LED device wiring line, and the blue LED device wiring line which are driven by the power voltage; and

each wiring line independently performs luminance control.

13. The illumination device according to claim 1, wherein:

any of the plurality of red LED devices, the plurality of green LED devices, or the plurality of blue LED devices include two or more types of LED devices having different wavelengths.

14. The illumination device according to claim 13, wherein:

the plurality of red LED devices include two types of LED devices having different luminescence wavelengths for a light source and infrared communication.

15. The illumination device according to claim 1, wherein:

each of the wiring line having the plurality of red LED devices implemented in series, the wiring line having the plurality of green LED devices implemented in series, and the wiring line having the plurality of blue LED devices implemented in series has a device resistance.

16. The illumination device according to claim 15, wherein:

the device resistance is under temperature-compensation control which controls a temperature coefficient so as to cancel the temperature dependency of the LED devices.

17. A liquid crystal display device comprising:

a liquid crystal display panel including a pair of transparent substrates and a liquid crystal layer arranged between the pair of transparent substrates; and

an illumination device provided on the rear surface of the liquid crystal display panel;

wherein the illumination device includes a plurality of light source modules, each module comprising a substrate;

a plurality of wiring lines provided on the substrate; and

a plurality of LED devices implemented in the wiring lines;

wherein the plurality of LED devices include a plurality of red LED devices, a plurality of green LED devices, and a plurality of blue LED devices;

wherein the plurality of wiring lines include a wiring line having the plurality of red LED devices implemented in series, a wiring line having the plurality of green LED devices implemented in series, and a wiring line having the plurality of blue LED devices implemented in series; and

wherein the plurality of wiring lines are connected in parallel and driven by a single power voltage.

18. The liquid crystal display device according to claim 17, wherein:

each of the plurality of light source modules independently performs luminance control.

19. A liquid crystal display device comprising:

a liquid crystal display panel including a pair of transparent substrates and a liquid crystal layer arranged between the pair of transparent substrates; and

a illumination device provided on the rear surface of the liquid crystal display panel;

wherein the illumination device includes a plurality of light source modules, each module comprising a substrate, a plurality of wiring lines provided on the substrate, and a plurality of white LED devices implemented in the wiring lines;

wherein the plurality of white LED light sources include a package configuration composed of a plurality of blue LED devices and fluorescent paste optically excited by the blue LED devices;

wherein the plurality of wiring lines include a wiring line having the plurality of white LED light sources implemented in series; and

wherein the plurality of wiring lines are connected in parallel and driven by a single power voltage.

20. The liquid crystal display device according to claim 19, wherein:

each of the plurality of light source modules independently performs luminance control.