Liquid-crystal display device

• US 6,781,648 B2
• Filed: 12/17/2001
• Issued: 08/24/2004
• Est. Priority Date: 12/22/2000
• Status: Expired due to Fees

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Kato, Hideaki, Takahashi, Yuji, Kaga, Koichi, Matsumura, Kanae
• Primary Examiner(s): Parker, Kenneth
• Assistant Examiner(s): Chung, David Y.
• Application Number:
  US10/015,624
• Publication Number:
  US 20020080301A1
• Time in Patent Office: 981 Days
• Field of Search: 349/50, 349/68, 362/26, 362/27, 362/31, 385/901
• US Class Current: 349/68
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 1/133622 Colour sequential illumination
• CPC Class Codes: G02F 2203/34 Colour display without the use of colour mosaic filters
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources

Abstract

A light source in a backlight portion is composed of red LEDs, green LEDs, and blue LEDs. The numbers of respective kinds of LEDs used are selected so that the number of blue LEDs is not smaller than the number of red LEDs and the number of blue LEDs is not smaller than the number of green LEDs.

Claims

1. A color-filterless full color liquid-crystal display device, comprising:

a liquid-crystal shutter portion including a liquid crystal; and

a backlight portion including light source units and a planar light guide, wherein said light source units comprise at least one red light-emitting device (LED), at least one green LED, and at least one blue LED,

wherein a first number corresponding to said at least one blue LED is not smaller than a second number corresponding to said at least one red LED, and the first number corresponding to said at least one blue LED is not smaller than a third number corresponding to said at least one green LED,

wherein said light source units are disposed on an edge of said planar light guide, and

wherein the number of said blue LEDs is not smaller than the number of said red LEDs and the number of said blue LEDs is larger than the number of said green LEDs.

20. A liquid-crystal display device according to claim 1, wherein said backlight portion includes a planar light guide laminated on said liquid-crystal shutter portion so that said at least one red LED, said at least one green LED, and said at least one blue LED are disposed to face a side of said planar light guide.

21. A liquid-crystal display device according to claim 20, wherein a reflection layer is formed on a surface of said planar light guide.

22. A liquid-crystal display device according to claim 1, wherein said backlight portion includes a light emission controller for controlling light emission of each of said at least one red LED, said at least one green LED, and said at least one blue LED, said light emission controller applying a current to said each of said at least one red LED, said at least one green LED, and said at least one blue LED to thereby obtain a maximum light-emitting efficiency of said each of said at least one red LED, said at least one green LED, and said at least one blue LED.

23. A liquid-crystal display device according to claim 1, wherein light is selectively emitted from each of said at least one red LED, said at least one green LED, and said at least one blue LED in synchronization with an ON/OFF of a corresponding one of a plurality of pixels in said liquid-crystal shutter portion.

2. A color-filterless full color liquid-crystal display device, comprising:

a liquid-crystal shutter portion including a liquid crystal; and

a backlight portion including light source units and a planar light guide,

wherein said light source units comprise at least one red light-emitting device (LED), at least one green LED, and at least one blue LED,

wherein a first number corresponding to said at least one blue LED is not smaller than a second number corresponding to said at least one red LED, and the first number corresponding to said at least one blue LED is not smaller than a third number corresponding to said at least one green LED,

wherein said light source units are disposed on an edge of said planar light guide, and

wherein two red LEDs, one green LED and two blue LEDs are mounted on a substrate.

24. A liquid-crystal display device according to claim 2, wherein said backlight portion includes a planar light guide laminated on said liquid-crystal shutter portion so that said at least one red LED, said at least one green LED, and said at least one blue LED are disposed to face a side of said planar light guide.

25. A liquid-crystal display device according to claim 24, wherein a reflection layer is formed on a surface of said planar light guide.

26. A liquid-crystal display device according to claim 2, wherein said backlight portion includes a light emission controller for controlling light emission of each of said at least one red LED, said at least one green LED, and said at least one blue LED, said light emission controller applying a current to said each of said at least one red LED, said at least one green LED, and said at least one blue LED to thereby obtain a maximum light-emitting efficiency of said each of said at least one red LED, said at least one green LED, and said at least one blue LED.

27. A liquid-crystal display device according to claim 2, wherein light is selectively emitted from each of said at least one red LED, said at least one green LED, and said at least one blue LED in synchronization with an ON/OFF of a corresponding one of a plurality of pixels in said liquid-crystal shutter portion.

3. A color-filterless fall color liquid-crystal display device, comprising:

a liquid-crystal shutter portion including a liquid crystal; and

a backlight portion including light source units and a planar light guide,

wherein said light source units comprise at least one red light-emitting device (LED), at least one green LED, and at least one blue LED,

wherein a first number corresponding to said at least one green LED is not larger than a second number corresponding to said at least one red LED and the first number corresponding to said at least one green LED is not larger than or equal to a third number corresponding to said at least one blue LED,

wherein said light source units are disposed on an edge of said planar light guide, and

wherein two red LEDs, one green LED and two blue LEDs are mounted on a substrate.

4. A liquid-crystal display device according to claim 3, wherein said backlight portion includes a planar light guide laminated on said liquid-crystal shutter portion so that said at least one red LED, said at least one green LED, and said at least one blue LED are disposed to face a side of said planar light guide.

5. A liquid-crystal display device according to claim 3, wherein a reflection layer is formed on a surface of said planar light guide.

6. A liquid-crystal display device according to claim 3, wherein said backlight portion includes a light emission controller for controlling light emission of each of said at least one red LED, said at least one green LED, and said at least one blue LED, said light emission controller applying a current to said each of said at least one red LED, said at least one green LED, and said at least one blue LED to thereby obtain a maximum light-emitting efficiency of said each of said at least one red LED, said at least one green LED, and said at least one blue LED.

7. A liquid-crystal display device according to claim 3, wherein light is selectively emitted from each of said at least one red LED, said at least one green LED, and said at least one blue LED in synchronization with an ON/OFF of a corresponding one of a plurality of pixels in said liquid-crystal shutter portion.

10. A liquid-crystal display according to claim 3, wherein said liquid crystal comprises a TN liquid crystal.

11. A liquid-crystal display according to claim 3, wherein said liquid crystal comprises an STN liquid crystal.

8. A color-filterless full color liquid-crystal display device, comprising:

a liquid-crystal shutter portion including a twisted nematic (TN) liquid crystal; and

a backlight portion including light source units and a planar lightguide,

wherein said light source units comprise at least one red light-emitting device (LED), at least one green LED, and at least one blue LED,

wherein a first number corresponds to said at least one blue LED, a second number corresponds to said at least one red LED, and third number corresponds to said at least one green LED, and said second number is larger than at least one of said first number and said third number, and

wherein said light source units are disposed on an edge of said planar light guide.

9. A color-filterless full color liquid-crystal display device, comprising:

a liquid-crystal shutter portion including a super twisted nematic (STN) liquid crystal; and

a backlight portion including light source units and a planar lightguide,

wherein said light source units comprise at least one red light-emitting device (LED), at least one green LED, and at least one blue LED,

wherein a first number corresponding to said at least one blue LED is not smaller than a second number corresponding to said at least one red LED, and the first number corresponding to said at least one blue LED is larger than a third number corresponding to said at least one green LED, and

wherein said light source units are disposed on an edge of said planar light guide.

12. A color-filterless full color liquid-crystal display device, comprising:

a liquid-crystal shutter portion including a liquid crystal; and

a backlight portion including light source units and a light guide,

wherein said light source units comprise at least one red light-emitting device (LED), at least one green LED, and at least one blue LED,

wherein a first number corresponding to said at least one blue LED is not smaller than a second number corresponding to said at least one red LED, and the first number corresponding to said at least one blue LED larger than a third number corresponding to said at least one green LED, and

wherein said light source units are disposed on an edge of said light guide.

13. A liquid-crystal display device according to claim 12, wherein said liquid crystal comprises a twisted nematic (TN) liquid crystal.

14. A liquid-crystal display device according to claim 12, wherein said liquid crystal comprises a super twisted nematic (STN) liquid crystal.

15. The color-filterless full color liquid-crystal display device according to claim 12, wherein said light guide comprises a planar light guide.

16. A color-filterless full color liquid-crystal display device, comprising:

a liquid-crystal shutter portion including a liquid crystal; and

a backlight portion including light source units and a light guide,

wherein said light source units comprise at least one red LED, at least one green LED, and at least one blue LED,

wherein a first number corresponding to said at least one green LED is not larger than a second number corresponding to said at least one red LED and the first number corresponding to said at least one green LED is not larger than or equal to a third number corresponding to said at least one blue LED, and

wherein said light source units are disposed on an edge of said light guide.

17. A liquid-crystal display device according to claim 16, wherein said liquid crystal comprises a twisted nematic (TN) liquid crystal.

18. A liquid-crystal display device according to claim 16, wherein said liquid crystal comprises a super twisted nematic (STN) liquid crystal.

19. The color-filterless full color liquid-crystal display device according to claim 16, wherein said light guide comprises a planar light guide.