Night vision compatible display backlight

• US 20070171623A1
• Filed: 01/24/2006
• Published: 07/26/2007
• Est. Priority Date: 01/24/2006
• Status: Active Grant

• Current Assignee: Astronautics Corporation of America
• Original Assignee: Astronautics Corporation of America
• Inventors: Zagar, Peter, Ulijasz, Thaddeus
• Granted Patent: US 7,525,611 B2
• Time in Patent Office: Days
• US Class Current: 362/29
• CPC Class Codes: B60K 2360/33 Illumination features
• CPC Class Codes: B60K 35/00 Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
• CPC Class Codes: G01D 11/28 Structurally-combined illuminating devices
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133626 providing two modes of illumination, e.g. day-night

Abstract

A system and method of backlighting a display using LEDs is night vision viewing compatible and requires no filters. The backlight includes an array of LEDs and a controller configured to selectively illuminate the LEDs in the array. The array of LEDs includes orange LEDs that are illuminated during a night vision viewing mode and may include red LEDs that are illuminated in a non-night vision viewing mode.

Claims

1. A backlighting system for a display comprising:

an array of light-emitting diodes (LEDs) configured to backlight the display;

a controller configured to selectively illuminate at least one of the LEDs in the array of LEDs; and

wherein the array of LEDs includes an orange LED, a green LED, and a blue LED.

2. The backlighting system of claim 1 further comprising a red LED in the array of LEDs.

3. The backlighting system of claim 2 wherein the controller is further configured to control the array of LEDs according to a first operational mode wherein a first group of LEDs are illuminated to backlight the display and a second operational mode wherein a second group of LEDs are illuminated to backlight the display.

4. The backlighting system of claim 3 wherein the controller is further configured to illuminate the red LED when in the first operational mode, and illuminate the orange LED and not the red LED when in the second operational mode.

5. The backlighting system of claim 3 further comprising a user control configured to switch from the first operational mode to the second operational mode.

6. The backlighting system of claim 5 wherein the controller provides a substantially continuous control of backlight illumination and wherein the controller is further configured to automatically switch from the first operational mode to the second operational mode at a given intensity as the intensity of the LEDs is continuously varied using the user control.

7. The backlighting system of claim 3 wherein the second operational mode does not include illumination intensities and wavelengths above a maximum level designated for a night vision imaging system (NVIS) standard compliant systems.

8. The backlighting system of claim 1 further comprising far infrared filter arranged over one of the array of LEDs and given LEDs in the array of LEDs.

9. The backlighting system of claim 1 further comprising at least one filter arranged over at least one LED in the array of LEDs to reduce radiation in at least one of lower NVIS band and an upper NVIS band.

10. The backlighting system of claim 1 wherein the display is a liquid crystal display.

11. The backlighting system of claim 1 further comprising at least one of a diffusing layer and a mixing layer disposed between the array of LEDs and the display and wherein the diffusing layer is configured to diffuse light generated by the array of LEDs and the mixing layer is configured to distribute light generated by the array of LEDs generally evenly.

12. A backlighting system for a display comprising:

a plurality of LEDs grouped into sets of LEDs; and

a controller configured to switch each set of LEDs between a first operating mode having a first group of LEDs activated to backlight the display, and a second operating mode having a second group of LEDs activated to backlight the display.

13. The backlighting system of claim 12 wherein each set of LEDs includes a red LED, an orange LED, a green LED, and a blue LED.

14. The backlighting system of claim 13 wherein the controller is further configured to activate the red LED, the green LED, and the blue LED to operate according to the first operating mode and to activate the orange LED, the green LED, and the blue LED to operate according to the second operating mode.

15. The backlighting system of claim 12 wherein an illumination produced in the first operating mode is designed for viewing the display in daylight, and an illumination produced in the second operating mode is designed for viewing the display in non-daylight.

16. The backlighting system of claim 12 wherein an illumination produced in the second operating mode is MIL-STD-3009 compliant.

17. The backlighting system of claim 12 further comprising a filter position over at least one of the plurality of LEDs in each set of LEDs configured to reduce an intensity of light produced in at least one of a lower NVIS band and an upper NVIS band.

18. The backlighting system of claim 12 wherein each of the LEDs are thin film LEDs.

19. The backlighting system of claim 12 wherein the plurality of LEDs form a cockpit illumination system for a cockpit display.

20. The backlighting system of claim 12 wherein the LEDs are arranged in at least one of an edge-lit arrangement and a back-lit arrangement.

21. A method of backlighting an LCD display comprising:

activating a plurality of LEDs including red LEDs during a first operating condition;

activating a plurality of LEDs including orange LEDs during a second operating condition; and

wherein an intensity of light emitted during the second operating condition complies with a night vision standard for viewing the LCD display.

22. The method of claim 21 further comprising deactivating the red LEDs during the second operating condition.

23. The method of claim 21 wherein the night vision viewing standard includes an NVIS, Type II, Class B standard.

24. The method of claim 21 wherein the first operating condition is non-night vision viewing of the display and the second operating condition is a night vision viewing of the display.

25. The method of claim 21 further comprising adjusting an intensity of at least a first colored LED in the plurality of LEDs to provide spectral components of the plurality of LEDs according to a desired ratio.