LED based light guide for dual mode aircraft formation lighting

• US 20040196646A1
• Filed: 12/18/2003
• Published: 10/07/2004
• Est. Priority Date: 04/04/2003
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Ferguson, Joseph L., Singer, Jeffrey M., Mangum, Scott R., Machi, Nicolo F.
• Granted Patent: US 7,278,766 B2
• Time in Patent Office: Days
• US Class Current: 362/602
• CPC Class Codes: B64D 2203/00 Aircraft or airfield lights using LEDs
• CPC Class Codes: B64D 47/06 for indicating aircraft presence
• CPC Class Codes: G02B 2006/0098 for scanning
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/006 to produce indicia, symbols, texts or the like
• CPC Class Codes: G02B 6/25 Preparing the ends of light guides for coupling, e.g. cutting
• CPC Class Codes: G02B 6/262 Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements
• CPC Class Codes: G02B 6/32 having lens focusing means positioned between opposed fibre ends with lens being an integral part of the single fibre end G02B6/262

Abstract

A lighting device (1) includes one or more diode light sources (32), which are configured to emit light into the peripheral edges of a light guide (20). The light guide (20) includes a set of diffusing elements (22) for scattering the emitted light in a plurality of directions out of the front surface of the light guide (20). The diffusing elements (22) are distributed on the light guide (20) so that the scattered light achieves a particular characteristic, e.g., improved uniformity.

Claims

1. A lighting device utilizing a diode light source, the device comprising:

a reflective base;

a light guide configured in front of the reflective base, the light guide including a plurality of diffusing elements; and

one or more diode light sources each configured to emit light in a direction incident to a peripheral edge of the light guide,

wherein the diffusing elements are configured to scatter the emitted light in a plurality of directions out of a front surface of the light guide.

2. The device of claim 1, wherein the diffusing elements are distributed on a rear surface of the light guide according to a configuration designed to achieve a perceived characteristic.

3. The device of claim 2, wherein the configuration is designed to achieve uniformity of a perceived brightness of the scattered light as viewed from the plurality of directions.

4. The device of claim 2, wherein the configuration is designed to achieve uniformity of a perceived brightness of the scattered light along the length of the front surface.

5. The device of claim 2, wherein the configuration is designed according to computer simulation.

6. The device of claim 2, wherein the configuration includes at least one of a shape, size, and relative spacing of the diffusing elements.

7. The device of claim 2, wherein the diffusing elements comprise etchings on the rear surface of the light guide.

8. The device of claim 7, wherein the light guide is made of a transparent plastic material.

9. The device of claim 7, wherein the diffusing elements are laser etched on the rear surface of the light guide.

10. The device of claim 2, wherein the diffusing elements are applied on the rear surface of the light guide by at least one of painting and printing.

11. The device of claim 1, wherein the diode light sources include at least two diode light sources each configured to emit light at a different wavelength.

12. The device of claim 11, wherein the diode light sources include one or more infrared (IR) diodes configured to emit infrared light.

13. The device of claim 12, wherein

the diode light sources further include one or more LEDs configured to emit visible light, and

the LEDs are operable to emit light when the according to a first mode of operation and the IR diodes are operable to emit infrared light according to a second mode of operation.

14. The device of claim 1, wherein the diode light sources include at least two diode light sources each configured to emit light at substantially the same wavelength.

15. The device of claim 1, further comprising:

a diffuse transmissive layer configured in front of the light guide to redirect the scattered light passing out of the front surface of the light guide.

16. The device of claim 15, wherein the diffuse transmissive layer is configured, based on the configuration of the diffusing elements, to redirect the scattered light to improve uniformity of a perceived brightness.

17. The device of claim 15, further comprising:

an outer lens, the diffuse transmissive layer being implemented as part of the outer lens.

18. The device of claim 15, wherein an accumulative thickness of the diffuse transmissive layer, light guide, and reflective layer is substantially equal to, or less than, ½

of an inch (1.27 cm).

19. The device of claim 1, wherein the reflective base includes a reflective layer adjacent to the diffusing elements of the light guide, the reflective layer being configured to reflect light scattered by the diffusing elements out of the front surface of the light guide.

20. The device of claim 1, wherein the device is mounted on the exterior of an aircraft for use as a formation light.

21. A method of outputting a formation light from the exterior of an aircraft, comprising:

emitting light from one or more diode light sources in a direction incident to a peripheral edge of a light guide;

scattering the emitted light with diffusing elements in the light guide, the diffusing elements being configured to scatter the emitted light out of the light guide in a plurality of directions; and

reflecting light that is scattered out of the light guide through a rear surface, so that the reflected light exits a front surface of the light guide.

22. The method of claim 21, wherein the scattering step uses diffusing elements etched on a rear surface of the light guide to scatter the emitted light, the light guide being made of a transparent plastic material.

23. The method of claim 21, wherein the scattering step uses diffusing elements that are painted on a rear surface of the light guide, the diffusing elements being distributed over the rear surface of the light guide.

24. The method of claim 21, further comprising:

redirecting the scattered light with a diffuse transmissive layer in front of the front surface of the light guide, wherein the redirecting step improves a uniformity of a perceived brightness.

25. The method of claim 21, further comprising:

distributing the diffusing elements on the rear surface of the light guide according to a configuration designed to achieve a perceived characteristic.

26. The method of claim 25, wherein the configuration is designed to achieve uniformity of a perceived brightness of the scattered light among the plurality of directions.

27. The method of claim 25, wherein the configuration is designed to achieve uniformity of a perceived brightness of the scattered light along at least one of a length and width of the front surface.

28. The method of claim 21, further comprising determining a configuration of the diffusing elements using a computer simulation.

29. The method of claim 21, the diode light sources including one or more light emitting diodes (LEDs) and one or more infrared (IR) diodes, the method further comprising:

emitting light from the LEDs in response to a first mode being chosen; and

emitting infrared light from the IR diodes in response to a second mode being chosen.