INTEGRATED LIGHT EMITTING AND LIGHT DETECTING DEVICE

• US 20100187422A1
• Filed: 09/14/2009
• Published: 07/29/2010
• Est. Priority Date: 01/23/2009
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Sethi, Gaurav, Kothari, Manish, Griffiths, Jonathan Charles, Webster, James Randolph, Govil, Alok
• Granted Patent: US 8,138,479 B2
• Time in Patent Office: Days
• US Class Current: 250/353
• CPC Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• CPC Class Codes: G06F 3/0428 by sensing at the edges of the touch surface the interruption of optical paths, e.g. an illumination plane, parallel to the touch surface which may be virtual sensing beam interruptions in a planar beam grid of an optical touch-screen G06F3/0421
• CPC Class Codes: H05B 47/115 by determining the presence or movement of objects or living beings
• CPC Class Codes: H05B 47/13 by using passive infrared detectors
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

Methods and systems for providing a light device that can emit light and sense light are disclosed. In one embodiment, a lighting device includes a light guide having a planar first surface, the light guide configured such that at least some ambient light enters the light guide through the first surface and propagates therein, and at least one light detector disposed along an edge of the light guide, the at least one detector optically coupled to the light guide to receive light propagating therein. The light detector can be configured to produce a control signal. In some embodiments, the lighting device also includes at least one light turning feature disposed on the first surface, the at least one light turning feature configured to direct light incident into the light guide through the first surface.

Claims

1. A lighting device, comprising:

a first light guide having a planar first surface and a planar second surface;

at least one light gathering feature disposed on the first surface and configured to couple light incident on the first surface of the first light guide into the first light guide; and

at least one light detector disposed along an edge of the first light guide coupled to the first light guide to receive light propagating therein, the at least one light detector configured to produce a control signal.

2. The device of claim 1, wherein the at least one light gathering feature comprises at least one of a diffractive feature, a reflective feature, a refractive feature, and a holographic film.

3. The device of claim 1, wherein the at least one light detector further comprises an output terminal, and wherein the at least one light detector is configured to provide the control signal to the output terminal for providing to a device electrically connected to the output terminal.

4. The device of claim 1, further comprising:

at least one light source optically coupled to at least one edge of the first light guide; and

at least one light turning feature configured to direct light propagating in the first light guide out of the first light guide.

5. The device of claim 4, wherein the control signal is configured to control at least a portion of the output of the at least one light source.

6. The device of claim 4, wherein the at least one light turning feature comprises a plurality of light turning features disposed on the front surface and the back surface of the first light guide.

7. The device of claim 4, wherein the at least one light detector is configured to sense IR radiation and the at least one light source comprises a visible light source.

8. The device of claim 4, wherein the at least one light detector is configured to sense visible light and the at least one light source comprises an IR radiation source.

9. The device of claim 4, wherein the at least one light detector is configured to sense IR radiation and the at least one light source comprises an IR radiation source.

10. The device of claim 4, wherein the at least one light detector is configured to sense visible light and the at least one light source comprises a visible light source.

11. The device of claim 4, wherein the at least one light turning feature comprises a feature selected from the group consisting of dots, grooves, diffractive gratings, holograms, and prismatic features.

12. The device of claim 4, wherein the at least one light source is configured to emit light having a wavelength within a first range and the at least one light detector is configured to detect light having a wavelength within a second range.

13. The device of claim 12, wherein the first range and the second range overlap.

14. The device of claim 12, wherein the first range and the second range do not overlap.

15. The device of claim 1, wherein the at least one light detector comprises a photodiode.

16. The device of claim 1, wherein the at least one light detector comprises:

a first detector disposed on a first edge of the first light guide; and

a second detector disposed on a second edge of the first light guide.

17. The device of claim 16, wherein the first and second detectors are each configured to provide control signals based on the light they receive.

18. The device of claim 17, further comprising a sensing circuit electronically coupled to the first detector and the second detector, the sensing circuit configured to determine a signal indicating a variation of light incident on the light guide based on the control signals provided by the first and second detector.

19. The device of claim 16, wherein the first edge is disposed opposite to the second edge across the first light guide.

20. The device of claim 19, wherein the sensing circuit signal is further configured to provide an indication of a direction of variation of incident light across the light guide.

21. The device of claim 16, wherein the first and second detectors are configured to produce a signal indicative of an object moving across at least a portion of the first surface that affects the light incident on the first surface.

22. The device of claim 1, further comprising:

a second light guide disposed parallel to the first light guide; and

an isolation layer disposed between the first light guide and the second light guide, the isolation layer configured to prevent at least some light propagating in the first light guide from entering the second light guide, and prevent at least some light propagating in the second light guide from entering the first light guide.

23. The device of claim 22, wherein the isolation layer comprises a material having a refractive index lower than the refractive index of the first and second light guide.

24. The device of claim 22, wherein the isolation layer has a refractive index that is between about 1.4 and about 1.6, the first light guide has a refractive index that is between about 1.4 and about 1.6, and the second light guide has a refractive index that is between about 1.4 and about 1.6.

25. The device of claim 22, wherein the isolation layer comprises a material with an index of refraction between about 1.4 and about 1.6.

26. The device of claim 1, wherein the at least one light gathering feature comprises a feature selected from the group consisting of dots, grooves, diffractive gratings, holograms, and prismatic features.

27. A lighting system comprising:

a first lighting device comprising

a first light guide having a planar first surface and a planar second surface,

at least one light gathering feature disposed on the first surface and configured to couple light incident on the first surface of the first light guide into the first light guide,

at least one light detector disposed along an edge of the first light guide coupled to the first light guide to receive light propagating therein,

at least one light source optically coupled to at least one edge of the first light guide, and

at least one light turning feature configured to direct light propagating in the first light guide out of the first light guide; and

a second lighting device configured to provide a control signal to the at least one light detector, wherein the at least one light detector is configured to control the light output from the at least one light source.

28. The device of claim 27, wherein the control signal comprises light output from the second lighting device.

29. The device of claim 28, wherein the light output from the second lighting device is pulse width modulated.

30. A method of manufacturing a lighting device, comprising:

providing a light guide having a planar first surface and a planar second surface;

disposing a first light detector along one or more edges of the light guide, the first light detector coupled to the first light guide to receive light propagating therein;

disposing a second light detector along one or more edges of the light guide, the first light detector coupled to the first light guide to receive light propagating therein;

forming a sensing circuit electronically coupled to the first light detector and the second light detector, the sensing circuit configured to determine a signal indicating variation of light incident on the light guide based on signals provided by the first and second detector;

forming at least one light gathering feature on at least one of the first surface and the second surface, the at least one light gathering feature configured to direct light incident on the light guide into the light guide;

forming at least one light turning feature on at least one of the first and the second surface, the at least one light turning feature configured to direct light propagating within the light guide away from the light guide; and

disposing at least one light source along one or more edges of the light guide.

31. A lighting device, comprising:

means for guiding light;

means for detecting light, the means for detecting light disposed along one or more edges of the means for guiding light, the means for detecting light configured to detect light propagating within the means for guiding light, the means for detecting light further configured to produce a control means; and

means for gathering light disposed on the means for guiding light, the means for gathering light configured to couple light incident on the means for guiding light into the means for guiding light.

32. The lighting device of claim 31, wherein the means for guiding light comprises a light guide having a planar first surface and a planar second surface.

33. The lighting device of claim 31, wherein the means for detecting light comprises at least one light detector disposed along an edge of the means for guiding light and coupled to the means for guiding light to receive light propagating therein.

34. The lighting device of claim 31, wherein the means for gathering light comprises one or more light gathering features.

35. The lighting device of claim 31, further comprising:

means for producing light, the means for producing light coupled to the means for guiding light; and

means for turning light disposed on the means for guiding light, the means for turning light configured to direct light propagating within the means for guiding light away from the means for guiding light.

36. The lighting device of claim 35, wherein the means for turning light comprises at least one light turning feature.

37. The lighting device of claim 35, wherein the means for producing light comprises at least one light source.

38. A method of sensing the movement of an object across a lighting panel based on the variation of light incident on the lighting panel, the lighting panel having at least two detectors coupled to the lighting panel, the method comprising:

at a first time,

receiving light propagating within the lighting panel at the first detector and producing a first signal, the first signal indicating the amount of light detected by the first light detector at the first time, and

receiving light propagating within the lighting panel at the second detector and producing a second signal, the second signal indicating the amount of light detected by the second detector at the first time;

at a second time,

receiving light propagating within the lighting panel at the first detector and producing a third signal, the third signal indicating the amount of light detected by the first light detector at the second time, and

receiving light propagating within the lighting panel at the second detector and producing a fourth signal, the fourth signal indicating the amount of light detected by the second detector at the second time; and

determining the direction of the movement of the object based on first, second, third, and fourth signals.

39. The method of claim 38, further comprising emitting light from the light panel wherein receiving light propagating within the lighting panel at the first time and the second time comprises receiving ambient light that is incident on the lighting panel and light that was emitted from the light panel and reflected back toward the lighting panel.