Backlight and liquid crystal display device

• US 20050141244A1
• Filed: 04/23/2004
• Published: 06/30/2005
• Est. Priority Date: 12/26/2003
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Fujitsu Display Technologies Corporation (Fujitsu Limited)
• Inventors: Suzuki, Toshihiro, Hamada, Tetsuya
• Granted Patent: US 7,556,415 B2
• Time in Patent Office: Days
• US Class Current: 362/612
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0085 Means for removing heat created by the light source from the package heat extraction or cooling elements for semiconductor light sources in general H01L33/64
• CPC Class Codes: G02B 6/0091 of the light source relative to the light guide G02B6/0021 takes precedence
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

A side light type backlight includes a light source including a plurality of LEDs, and a light guide plate. One of the end surfaces of the light guide plate is a light incidence surface at which a plurality of R-LEDs, a plurality of G-LEDs and a plurality of B-LEDs are arranged. LEDs satisfy the relationship of: a distribution range of light emitted from G-LEDs <a distribution range of light emitted from R-LEDS, or a distribution range of light emitted from G-LEDs <a distribution range of light emitted from B-LEDs. Also, LEDs are electrically connected to each other.

Claims

1. A side-light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, at least one of end surfaces of the light guide plate being a light incidence surface at which a plurality of R-LEDs, a plurality of G-LEDs and a plurality of B-LEDs are arranged, wherein the plurality of LEDs satisfy the relationship of:

a distribution range of light emitted from G-LEDs <

a distribution range of light emitted from R-LEDs or a distribution range of light emitted from G-LEDs<

a distribution range of light emitted from B-LEDs.

2. A side-light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which a plurality of R-LEDs, a plurality of G-LEDs and a plurality of B-LEDs are arranged, wherein a plurality of G-LEDs are arranged at one of the light incidence surfaces and a plurality of R-LEDs and a plurality of B-LEDs are arranged at the opposing light incidence surface.

3. A side-light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which a plurality of R-LEDs, a plurality of G-LEDs and a plurality of B-LEDs are arranged, wherein a plurality of G-LEDs and a plurality of B-LEDs are arranged on one of the light incidence surfaces and a plurality of R-LEDs are arranged on the opposing light incidence surface.

4. A side-light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, at least one of opposing end surfaces of the light guide plate being light incidence surface at which a plurality LEDs are arranged, wherein said plurality of LEDs includes a plurality of white LEDs and a plurality of B-LEDs.

5. A side-light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, at least one of opposing end surfaces of the light guide plate being a light incidence surface at which a plurality LEDs are arranged, wherein at least two rows of LEDs are arranged in a direction of a thickness of the light guide plate and the LEDs of each row are arranged in a longitudinal direction of the light incidence surface of the light guide plate.

6. A side-light type backlight as defined in claim 5, wherein the LEDs of the lower row are interposed between the LED positions of the upper row in the longitudinal direction of the light incidence surface of the light guide plate.

7. A side-light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which and a plurality LEDs are arranged, wherein the LEDs at both ends are arranged in such a fashion that a light emission portion of each of the LEDs opposes an extreme end of the light incidence surface of the light guide plate in a longitudinal direction.

8. A side-light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which the plurality of LEDs are arranged, wherein a frame is provided for accommodating the light source and the light guide plate, and a member having an elastic property or a spring property is arranged between the light source and the frame or between an end surface of the light guide plate opposing the light incidence surface in such a fashion as to press the LEDs to the light guide plate.

9. A side-light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which the plurality of LEDs are arranged, wherein the plurality of LEDs are mounted to a circuit substrate, and a member having a higher heat conductivity than that of air is interposed between one of mounting surfaces and surfaces other than light outgoing surfaces of the LEDs, and a surface of a housing of the light source or a surface of a frame constituting a backlight unit.

10. A side-light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which plurality of LEDs are arranged, wherein the plurality of LEDs are mounted to a circuit substrate, and one of the mounting surfaces and a surfaces other than light outgoing surfaces of the LEDs makes contact with a surface of a housing of the light source or a surface of a frame constituting a backlight unit.

11. A side-light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which the plurality of LEDs are arranged, wherein the light guide plate has a taper shape at an end portion thereof on the side of the light incidence surface, and a jig for fixing the LEDs has a taper shape substantially coming into close contact with the taper shape of the light guide plate.

13. A backlight as defined in claim 11, wherein at least a surface of the jig is a white color or a mirror surface.

12. A side-light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which the plurality of LEDs are arranged, wherein the plurality of LEDs are arranged with intervals among them, and a member is interposed between the LED and the LED.

23. A backlight as defined in claim 12, wherein at least a surface of the jig is a white color or a mirror surface.

14. A side light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which the plurality of LEDs are arranged, wherein the LEDs are mounted to a circuit substrate, and light emission surfaces of the LEDs protrude outward from the circuit substrate.

15. A side light type backlight comprising a light source including a plurality of LED, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which the plurality of LEDs are arranged, wherein M of the LEDs are arranged in a longitudinal direction of the light incidence surface of the light guide plate and electrically connected such that there are a plurality of groups of the LEDs with each group comprising N of LEDs mutually adjacently arranged in series.

16. A backlight as defined in claim 15, wherein N is 2 to 10.

17. A side light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which the plurality of LEDs are arranged, wherein M of the LEDs are arranged in a longitudinal direction of the light incidence surface of the light guide plate such that every S of the LEDs from the end are electrically connected to each other (S:

a positive integer).

18. A backlight as defined in claim 17, wherein S is 1 to 10.

19. A side light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which the plurality of LEDs are arranged, wherein a plurality of rows of the LEDs are arranged in a direction of a thickness of the light guide plate with each row of LEDs arranged in a longitudinal direction of the light incidence surface of the light guide plate, and electrically connected to one another in series.

20. A side light type backlight comprising a light source including a plurality of LEDs, and a light guide plate, opposing end surfaces of the light guide plate being light incidence surfaces at which the plurality of LEDs are arranged, wherein a plurality of rows of the LEDs are arranged in a direction of a thickness of the light guide plate, with each row of LEDs arranged in a longitudinal direction of the light incidence surface of the light guide plate, N number of the LEDs being electrically connected in series in which the LEDs adjacent to each other belong to different rows.

21-22. -22. (canceled)