LED backlight

• US 20060087866A1
• Filed: 10/22/2004
• Published: 04/27/2006
• Est. Priority Date: 10/22/2004
• Status: Abandoned Application

• Current Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Chew, Tong Fatt, Kuan, Yew Cheong, Ng, Kee Yean
• Application Number:
  US10/971,627
• Publication Number:
  US 20060087866A1
• Time in Patent Office: Days
• US Class Current: 362/612
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2105/12 characterised by the geometrical disposition of the light-generating elements, e.g. arranging light-generating elements in differing patterns or densities
• CPC Class Codes: F21Y 2107/50 on planar substrates or supports, but arranged in different planes or with differing orientation, e.g. on plate-shaped supports with steps on which light-generating elements are mounted
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133613 characterized by the sequence of light sources
• CPC Class Codes: G09F 13/04 Signs, boards or panels, illuminated from behind the insignia
• CPC Class Codes: H05K 1/189 characterised by the use of a flexible or folded printed circuit H05K3/326 takes precedence
• CPC Class Codes: H05K 3/0058 Laminating printed circuit boards onto other substrates, e.g. metallic substrates H05K1/0281 takes precedence

Abstract

A substrate of a backlight is positioned behind a transmissive display. A plurality of low-power light emitting diodes (LEDs) are mounted on the substrate. The LEDs are positioned behind the display, and each LED is nominally operated at ≦200 milliamps (and, more preferably, at ≦100 milliamps).

Claims

1. Apparatus, comprising:

a transmissive display; and

a backlight, comprising i) a substrate, positioned behind the display, and ii) a plurality of low-power light emitting diodes (LEDs), mounted on the substrate and positioned behind the display, each LED being nominally operated at ≦

200 milliamps.

2. The apparatus of claim 1, wherein the substrate is flexible.

3. The apparatus of claim 2, wherein the flexible substrate is mounted to a heatsink.

4. The apparatus of claim 3, wherein the heatsink is a copper foil.

5. The apparatus of claim 2, wherein the flexible substrate is formed to have a three-dimensional contour, the three-dimensional surface causing the LEDs to be oriented in two or more different directions with respect to each other.

6. The apparatus of claim 5, wherein the three-dimensional contour comprises angular surface transitions.

7. The apparatus of claim 5, wherein the three-dimensional contour comprises curved surface transitions.

8. The apparatus of claim 1, wherein the substrate is a printed circuit board.

9. The apparatus of claim 1, wherein the substrate is a lead-frame.

10. The apparatus of claim 1, further comprising a planar light guide, positioned between the display and the backlight.

11. The apparatus of claim 1, further comprising a light diffuser, positioned between the display and the backlight.

12. The apparatus of claim 1, further comprising one or more three-dimensional reflectors, mounted to the substrate;

wherein at least some of the LEDs are mounted within the reflectors.

13. The apparatus of claim 1, wherein the LEDs comprise red, green and blue LEDs.

14. The apparatus of claim 1, wherein at least some of the LEDs are mounted to the substrate in a spiral pattern.

15. The apparatus of claim 1, wherein at least some of the LEDs are mounted to the substrate in a circular pattern.

16. The apparatus of claim 1, wherein the LEDs are nominally operated at ≦

100 milliamps.

17. The apparatus of claim 1, further comprising a control system to supply direct current (DC) drive signals to the LEDs.

18. The apparatus of claim 1, further comprising a control system to supply pulse width modulated (PWM) drive signals to the LEDs.

19. The apparatus of claim 1, wherein at least some of the LEDs are mounted to the substrate in a radial spoke pattern.

20. The apparatus of claim 1, wherein at least some of the LEDs are mounted to the substrate in a serpentine pattern.

21. The apparatus of claim 1, wherein at least some of the LEDs are mounted to the substrate in multiple triangular groupings.

22. The apparatus of claim 1, wherein at least some of the LEDs are mounted to the substrate in multiple square groupings consisting of one red LED, two green LEDs, and one blue LED.