Lighting device, display device and television receiver

• US 8,550,644 B2
• Filed: 03/12/2010
• Issued: 10/08/2013
• Est. Priority Date: 06/03/2009
• 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: Kuromizu, Yasumori
• Primary Examiner(s): WALFORD, NATALIE K
• Application Number:
  US13/321,561
• Publication Number:
  US 20120069250A1
• Time in Patent Office: 1,306 Days
• Field of Search: None
• US Class Current: 362/97.1
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity

Abstract

A lighting device achieves power saving and a moderate illumination brightness distribution without having local dark portions. A lighting device 12 includes a light source 17, a chassis 14 and an optical member 15a. The optical member 15a includes a light source overlapping portion DA that overlaps a light source installation area LA where the light source 17 is arranged. A light reflecting portion 50 is formed on at least the light source overlapping portion DA. The optical member 50 has maximum light reflectance Rmax and minimum light reflectance Rmin, and the maximum light reflectance Rmax is 40% or higher in the light source overlapping portion DA and an entire half-value width H having light reflectance of (Rmax+Rmin)/2 occupies 25% to 80% in a transmission area TA of the optical member 15a through which the light from the light source transmits.

Claims

1. A lighting device comprising:

a light source;

a chassis configured to house the light source and have an opening for light from the light source to pass through, the chassis including a light source installation area in which the light source is arranged and an empty area in which no light source is arranged;

an optical member provided to face the light source and cover the opening, the optical member including a light source overlapping portion that overlaps the light source installation area and an empty area overlapping portion that overlaps the empty area; and

a light reflecting portion provided on at least the light source overlapping portion of the optical member and configured to reflect light from the light source, wherein;

in a light reflectance distribution in a surface area of the optical member, the surface of the optical member has maximum light reflectance Rmax and minimum light reflectance Rmin, and the maximum light reflectance Rmax is 40% or higher in the light source overlapping portion and an entire half-value width H having light reflectance of (Rmax+Rmin)/2 occupies 25% to 80% in a transmission area of the optical member through which the light from the light source transmits.

2. The lighting device according to claim 1, wherein the maximum light reflectance Rmax of the optical member is 65% or higher in the light source overlapping portion.

3. The lighting device according to claim 1, wherein the optical member has a middle portion having the maximum light reflectance Rmax.

4. The lighting device according to claim 1, wherein the light reflecting portion is configured by a dot pattern having light reflectivity.

5. The lighting device according to claim 1, wherein the light reflecting portion includes a material that provides white.

6. The lighting device according to claim 1, wherein the light reflecting portion includes a material that provides one of cyan and blue.

7. The lighting device according to claim 1, wherein the light reflecting portion is configured by mixing a material that provides white and a material that provides one of cyan and blue.

8. The lighting device according to claim 1, wherein the light reflecting portion has light reflectance decreasing in a continuous and gradual manner from a portion having high light reflectance toward a portion having low light reflectance.

9. The lighting device according to claim 1, wherein the light reflecting portion has light reflectance decreasing in a stepwise and gradual manner from a portion having high light reflectance toward a portion having low light reflectance.

10. The lighting device according to claim 1, wherein:

the chassis has a surface facing the optical member and including at least a first end portion, a second end portion, and a middle portion, the second end portion being located at an end away from the first end portion, and the middle portion being located between the first end portion and the second end portion;

at least one of the first end portion, the second end portion and the middle portion is configured as the light source installation area, and the rest is configured as the empty area.

11. The lighting device according to claim 10, wherein in the chassis, the light source installation area is smaller than the empty area.

12. The lighting device according to claim 10, wherein the light source installation area is formed in the middle portion of the chassis.

13. The lighting device according to claim 1, wherein the optical member is a light diffusing member configured to diffuse light from the light source.

14. The lighting device according to claim 1, wherein the optical member is adhered to the light diffusing member that diffuses light emitted from the light source.

15. The lighting device according to claim 1, wherein the optical member is provided on the light diffusing member with thermocompression bonding, the light diffusing member diffusing light emitted from the light source.

16. The lighting device according to claim 1, wherein the light source is a hot cathode tube.

17. The lighting device according to claim 1, wherein the light source is a cold cathode tube.

18. The lighting device according to claim 1, wherein the light source is an LED.

19. A display device comprising:

the lighting device according to claim 1; and

a display panel configured to provide display using light from the lighting device for a display device.

20. The display device according to claim 19, wherein the display panel is a liquid crystal display panel using liquid crystal.

21. A television receiver comprising the display device according to claim 19.