Light source device, backlight unit, and liquid crystal display device

• US 7,850,358 B2
• Filed: 05/18/2006
• Issued: 12/14/2010
• Est. Priority Date: 09/28/2005
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Hamada, Tetsuya
• Primary Examiner(s): O Shea; Sandra L
• Assistant Examiner(s): ALLEN, DANIELLE NICOLE
• Application Number:
  US12/088,113
• Publication Number:
  US 20090116223A1
• Time in Patent Office: 1,671 Days
• Field of Search: 362/97.1, 362/97.2, 362/97.3, 362/800, 362/600, 362/603, 362/611, 362/612, 362/561, 362/555
• US Class Current: 362/612
• CPC Class Codes: G02B 6/0031 Reflecting element, 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 6/0083 Details of electrical connections of light sources to drivers, circuit boards, or the like
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: H05B 45/48 having LEDs organised in strings and incorporating parallel shunting devices
• CPC Class Codes: H05K 1/181 associated with surface mounted components
• CPC Class Codes: H05K 2201/09072 Hole or recess under component or special relationship between hole and component
• CPC Class Codes: H05K 2201/10022 Non-printed resistor
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H05K 2201/10196 Variable component, e.g. variable resistor
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A light source device, a backlight unit, and a liquid crystal display device are each capable of improving uniformity of a luminance and a color of a display surface. The light source device includes a board; a plurality of point light sources arranged on a surface of the board and connected in series; and a variable resistor, wherein the variable resistor is disposed on the surface on which the plurality of point light sources are arranged of the board; at least one point light source arranged on an end side among the plurality of point light sources is connected in parallel to the variable resistor; and the board has a through-hole in a region where a variable resistor is located.

Claims

1. A light source device comprising:

a board;

a plurality of point light sources arranged on a surface of the board and connected in series; and

a variable resistor;

wherein

the variable resistor is disposed on the surface on which the plurality of point light sources are arranged on the board;

at least one of the point light sources arranged on an end side among the plurality of point light sources is connected in parallel to the variable resistor; and

the board has a through-hole in an area where the variable resistor is located.

2. The light source device according to claim 1, wherein the plurality of point light sources are light-emitting diodes.

3. The light source device according to claim 2, wherein the light-emitting diodes include a red light-emitting diode, a green light-emitting diode, and a blue light-emitting diode.

4. The light source device according to claim 2, wherein an amount of an electric current flowing into a variable resistor connected in parallel to one of the light-emitting diodes at an end is adjusted to about 50% or more and about 90% or less relative to an amount of an electric current flowing into the light emitting diode at the end.

5. The light source device according to claim 4, wherein an amount of an electric current flowing into a variable resistor connected in parallel to a second light-emitting diode from the end is adjusted to about 20% or more and about 50% or less relative to an amount of an electric current flowing into the second light-emitting diode from the end.

6. The light source device according to claim 5, wherein a green light-emitting diode is arranged at the end, and a blue light-emitting diode is arranged at the second from the end.

7. A backlight unit comprising the light source device of claim 1, wherein the plurality of point light sources are arranged on a side of a display surface facing toward a display surface side.

8. A backlight unit comprising the light source device of claim 1, wherein the plurality of point light sources are arranged just below a display surface facing toward the display surface.

9. A liquid crystal display device comprising the backlight unit of claim 7.

10. A liquid crystal display device comprising the backlight unit of claim 8.

11. A light source device comprising:

a board;

a plurality of point light sources arranged on a surface of the board and connected in series; and

a variable resistor;

wherein

the variable resistor is disposed on a surface opposite to the surface on which the plurality of point light sources are arranged; and

at least one of the point light sources arranged on an end side among the plurality of point light sources is connected in parallel to the variable resistor.

12. The light source device according to claim 11, wherein the plurality of point light sources are light-emitting diodes.

13. The light source device according to claim 12, wherein the light-emitting diodes include a red light-emitting diode, a green light-emitting diode, and a blue light-emitting diode.

14. The light source device according to claim 12, wherein an amount of an electric current flowing into a variable resistor connected in parallel to a light-emitting diode at an end is adjusted to about 50% or more and about 90% or less relative to an amount of an electric current flowing into the light-emitting diode at the end.

15. The light source device according to claim 14, wherein an amount of an electric current flowing into a variable resistor connected in parallel to a second light-emitting diode from the end is adjusted to about 20% or more and about 50% or less relative to an amount of an electric current flowing into the second light-emitting diode from the end.

16. The light source device according to claim 15, wherein a green light-emitting diode is arranged at the end, and a blue light-emitting diode is arranged at the second from the end.

17. A backlight unit comprising the light source device of claim 11, wherein the plurality of point light sources are arranged on a side of a display surface and are facing toward a display surface side.

18. A backlight unit comprising the light source device of claim 11, wherein the plurality of point light sources are arranged just below a display surface and are facing toward the display surface.

19. A liquid crystal display device comprising the backlight unit of claim 17.

20. A liquid crystal display device comprising the backlight unit of claim 18.