Light emitting diode backlight for liquid crystal displays

• US 20070081361A1
• Filed: 10/12/2006
• Published: 04/12/2007
• Est. Priority Date: 10/12/2005
• Status: Abandoned Application

• Current Assignee: Dupont Display Enhancements, Inc. (DuPont de Nemours, Inc.)
• Original Assignee: Dupont Display Enhancements, Inc. (DuPont de Nemours, Inc.)
• Inventors: Clary, Donald
• Application Number:
  US11/546,966
• Publication Number:
  US 20070081361A1
• Time in Patent Office: Days
• US Class Current: 362/624
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 1/133628 with cooling means

Abstract

The invention is directed to a backlight for a display which utilizes a light emitting diode array as a light source and is devoid a light guide.

Claims

1. A device for a display comprising:

a. a bottom surface opposing an open top;

b. opposing first and second sides;

c. opposing third and fourth sides;

wherein the opposing first, second, third and fourth sides independently make an angle found within the range of about 80°

to 100°

with the bottom surface and wherein the open top connects to the display;

a first plurality of light sources disposed on the first side and a second plurality of light sources disposed on the second side;

having a diffuse reflector material disposed on the bottom surface; and

the diffuse reflector material having a plurality of specular reflection material disposed thereon.

2. The device of claim 1 wherein the specular reflective material having a first plurality of strips parallel or nearly parallel to the first plurality of light sources and having a second plurality of strips that are parallel or nearly parallel to the second plurality of light sources.

3. The device of claim 2 wherein the first plurality of strips and the second plurality of strips are disposed on the bottom surface about one-fourth of distance from the respective light source.

4. The device of claim 1 wherein the first, second, third and fourth sides each makes an angle of about 90°

with the bottom surface.

5. The device of claim 1 wherein the first plurality of light sources and the second plurality of light sources are light emitting diodes (LEDs).

6. The device of claim 5 wherein the light emitting diodes are characterized to emit at least one color selected from the group consisting of red, green, and blue.

7. The device of claim 5 wherein the light emitting diodes are characterized to emit red, green, and blue light.

8. The device of claim 5 wherein the light emitting diodes are characterized to emit blue light and are coated with a yellow phosphor.

9. A device for a display comprising:

a. a bottom surface opposing an open top;

b. opposing first and second sides;

c. opposing third and fourth sides;

wherein the opposing first, second, third and fourth sides independently make an angle found within the range of about 80°

to 100° and

includes all values found therein with the bottom surface and wherein the open top connects to the display;

a first plurality of light sources disposed on the first side and a second plurality of light sources disposed on the second side;

having a diffuse reflector material disposed on the bottom surface wherein the diffuse reflector material is disposed between the first side and the second side and having a center being half length between the first side and the second side wherein the half length varies in a parabolic manner versus position from the center and the first side and the half length varies in a parabolic manner versus position from the center and the second side.

10. The device of claim 9 wherein placement of the diffuse white reflector within the device is done such that distance between the white reflector and the open top is greatest at one or both members of a set of opposing sides bearing the first and second pluralities of light sources.

11. The device of claim 9 wherein the first, second, third and fourth sides each makes an angle of about 90°

with the bottom surface and are perpendicular with the bottom surface.

12. The device of claim 9 wherein the first plurality of light sources and the second plurality of light sources are light emitting diodes (LEDs).

13. The device of claim 12 wherein the light emitting diodes are characterized to emit at least one color selected from the group consisting of red, green, and blue.

14. The device of claim 12 wherein the light emitting diodes are characterized to emit red, green, and blue light.

15. The device of claim 12 wherein the light emitting diodes are characterized to emit blue light and are coated with a yellow phosphor.