Compact optical wave-guide system for LED backlighting liquid crystal displays

• US 6,419,372 B1
• Filed: 09/08/2000
• Issued: 07/16/2002
• Est. Priority Date: 09/08/2000
• Status: Expired due to Term

• Current Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Shaw, James E., Mosier, Donald E.
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US09/657,693
• Time in Patent Office: 676 Days
• Field of Search: 349/61-69, 362/26, 362/27, 362/29-31, 362/555, 362/561, 362/800, 362/230, 362/231, 362/583
• US Class Current: 362/231
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133626 providing two modes of illumination, e.g. day-night
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines

Abstract

Disclosed are a flat panel display and a backlight which provides both night vision and day mode backlighting of the flat panel display. The backlight of the flat panel display includes a circuit card and day mode light emitting diodes (LEDs) positioned coplanar with each other on the circuit card. Night vision (NVIS) LEDs are positioned on the circuit card coplanar with the day mode LEDs. An optical wave-guide is positioned in front of the day mode LEDs and the NVIS LEDs and is adapted to distribute light from the day mode LEDs and from the NVIS LEDs forward away from the LEDs and the circuit card.

Claims

1. A backlight adapted for use in illuminating a flat panel display, the backlight comprising:

a circuit card;

a plurality of day mode light emitting diodes (LEDs) positioned coplanar with each other and coupled to the circuit card which powers the plurality of day mode LEDs during day mode operation of the backlight;

night vision (NVIS) LEDs positioned coplanar with the plurality of day mode LEDs and coupled to the circuit card which powers the NVIS LEDs during night mode operation of the backlight; and

an optical wave-guide positioned in front of the plurality of day mode LEDs and the NVIS LEDs and adapted to distribute light from the plurality of day mode LEDs and from the NVIS LEDs forward away from the LEDs and the circuit card.

2. The backlight of claim 1, wherein the NVIS LEDs are positioned outside of the plurality of day mode LEDs and are coupled to outer portions of the circuit card.

3. The backlight of claim 2, wherein the optical wave-guide is further adapted to redirect light from the NVIS LEDs toward a center of the wave-guide.

4. The backlight of claim 3, and further comprising NVIS filters positioned on the optical wave-guide, the NVIS filters filtering out non-NVIS frequencies of light generated by the NVIS LEDs.

5. The backlight of claim 3, wherein the optical wave-guide further includes reflective surfaces positioned adjacent the NVIS LEDs which reflect light generated by the NVIS LEDs toward the center of the wave-guide.

6. The backlight of claim 1, wherein the NVIS LEDs are spread across the circuit card such that they are positioned between day mode LEDs.

7. The backlight of claim 1, wherein the plurality of day mode LEDs include LEDs having a first color and LEDs having a second color such that the optical wave-guide mixes the first and second colors.

8. The backlight of claim 7, wherein the first color is a red-deficient white and wherein the second color is red.

9. The backlight of claim 1, wherein the optical wave-guide includes forward extending arms adapted to support an optical stack.

10. A flat panel display comprising:

an optical stack; and

a backlight comprising;

a circuit card;

a plurality of day mode light emitting diodes (LEDs) positioned coplanar with each other and coupled to the circuit card which powers the plurality of day mode LEDs during day mode operation of the backlight;

night vision (NVIS) LEDs positioned coplanar with the plurality of day mode LEDs and coupled to the circuit card which powers the NVIS LEDs during night mode operation of the backlight; and

an optical wave-guide positioned in front of the plurality of day mode LEDs and the NVIS LEDs and adapted to distribute light from the plurality of day mode LEDs and from the NVIS LEDs forward away from the LEDs and the circuit card.

11. The flat panel display of claim 10, wherein the NVIS LEDs are positioned outside of the plurality of day mode LEDs and are coupled to outer portions of the circuit card.

12. The flat panel display of claim 11, wherein the optical wave-guide is further adapted to redirect light from the NVIS LEDs toward a center of the wave-guide.

13. The flat panel display of claim 12, wherein the backlight further comprises NVIS filters positioned on the optical wave-guide, the NVIS filters filtering out non-NVIS frequencies of light generated by the NVIS LEDs.

14. The flat panel display of claim 12, wherein the optical wave-guide further includes reflective surfaces positioned adjacent the NVIS LEDs which reflect light generated by the NVIS LEDs toward the center of the wave-guide.

15. The flat panel display of claim 10, wherein the NVIS LEDs are positioned between day mode LEDs.

16. The flat panel display of claim 10, wherein the plurality of day mode LEDs include LEDs having a first color and LEDs having a second color such that the optical wave-guide mixes the first and second colors.

17. The flat panel display of claim 10, wherein the optical wave-guide includes forward extending arms adapted to support the optical stack.

18. A flat panel display comprising:

an optical stack including a display matrix; and

backlight means for providing coplanar night vision (NVIS) backlighting and day mode backlighting of the display matrix.