Integrated light emitting and light detecting device

• US 8,138,479 B2
• Filed: 09/14/2009
• Issued: 03/20/2012
• Est. Priority Date: 01/23/2009
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Kothari, Manish, Webster, James Randolph, Sethi, Gaurav, Govil, Alok, Griffiths, Jonathan Charles
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): TANINGCO, MARCUS H
• Application Number:
  US12/559,085
• Publication Number:
  US 20100187422A1
• Time in Patent Office: 918 Days
• Field of Search: 250/353
• 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 first edge, a second edge opposite to the first edge, a planar first surface extending between the first edge and the second edge, and a planar second surface opposite to the first 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;

a first light detector disposed along the first edge of the first light guide and coupled to the first light guide to receive light propagating therein, the first light detector configured to produce a first signal based on an amount of light received from the first light guide through the first edge; and

a second light detector disposed along the second edge of the first light guide and coupled to the first light guide to receive light propagating therein, the second light detector configured to produce a second signal based on an amount of light received from the first light guide through the second edge,

wherein the first light detector and the second light detector are electrically connected and configured to produce a control signal indicating a direction of movement of an object relative to the first edge and the second edge based at least in part on the first signal and the second 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, further comprising a differential amplifier including the first light detector and the second light detector, the differential amplifier having an output terminal, and being 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 first and second light detectors are 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 first and second light detectors are 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 first and second light detectors are 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 first and second light detectors are 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 first and second light detectors are 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 first and second light detectors comprise a photodiode.

16. 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.

17. The device of claim 16, wherein the isolation layer comprises a material having a refractive index lower than the refractive index of the first and second light guide.

18. The device of claim 16, 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.

19. The device of claim 16, wherein the isolation layer comprises a material with an index of refraction between about 1.4 and about 1.6.

20. 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.

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

providing a light guide having a first edge, a second edge opposite to the first edge, a planar first surface extending between the first edge and the second edge, and a planar second surface opposite to the first surface;

disposing a first light detector along the first edge of the light guide, the first light detector coupled to the first light guide to receive light propagating therein through the first edge, the first light detector configured to produce a first signal based on an amount of light received from the light guide through the first edge;

disposing a second light detector along the second edge of the light guide, the first light detector coupled to the first light guide to receive light propagating therein through the second edge, the second light detector configured to produce a second signal based on an amount of light received from the light guide through the second edge;

electrically connecting the first light detector and the second light detector, the first and second light detectors being configured to produce a control signal indicating a direction of movement of an object relative to the first edge and the second edge based at least in part on the first signal and the second signal;

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.

22. A lighting device, comprising:

means for guiding light having a first edge and a second edge opposite to the first edge;

first means for detecting light disposed along the first edge of the means for guiding light and coupled to the first means for guiding light to receive light propagating therein, the first means for detecting light configured to produce a first signal based on an amount of light received from the first means for guiding light through the first edge;

second means for detecting light disposed along the second edge of the means for guiding light and coupled to the first means for guiding light to receive light propagating therein, the second means for detecting light configured to produce a second signal based on an amount of light received from the first means for guiding light through the second edge;

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; and

means for detecting a direction of movement of an object relative to the first edge and the second edge based at least in part on a variation of incident light across the first means for guiding light between the first edge and the second edge, the detecting means including the first means for detecting light and the second means for detecting light and being configured to produce a control signal indicating the detected direction of movement of the object.

23. The lighting device of claim 22, wherein the means for guiding light comprises a light guide having a planar first surface and a planar second surface.

24. The lighting device of claim 22, wherein the first means for detecting light comprises at least one light detector.

25. The lighting device of claim 22, wherein the means for gathering light comprises one or more light gathering features.

26. The lighting device of claim 22, 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.

27. The lighting device of claim 26, wherein the means for turning light comprises at least one light turning feature.

28. The lighting device of claim 26, wherein the means for producing light comprises at least one light source.

29. A method of sensing a direction of 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 a first light detector coupled to a first edge of the lighting panel and a second light detector coupled to a second edge of the lighting panel, the second, edge being opposite to the first edge, 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 relative to the first and second edges based on the first, second, third, and fourth signals.

30. The method of claim 29, 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.