Integrated light emitting and light detecting device

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.

1 . A lighting device, comprising:
 a light guide having a first edge, a second edge, and a first surface extending between the first edge and the second edge, the first surface configured to receive incident light;   a first light detector disposed along the first edge of the light guide and coupled to the 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 light guide through the first edge; and   a second light detector disposed along the second edge of the light guide and coupled to the 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 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 light guide based at least in part on the first signal and the second signal.   
     
     
         2 . 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. 
     
     
         3 . The device of  claim 1 , wherein the control signal indicates a direction of movement of the object relative to the first edge and the second edge. 
     
     
         4 . The device of  claim 1 , wherein the control signal indicates a direction of movement of the object relative to the first surface. 
     
     
         5 . The device of  claim 4 , wherein the control signal indicates a change of distance between the first surface and the object. 
     
     
         6 . The device of  claim 1 , further comprising at least one light gathering feature disposed on the first surface and configured to couple light incident on the first surface into the light guide. 
     
     
         7 . The device of  claim 1 , further comprising:
 at least one light source optically coupled to at least one edge of the light guide; and   at least one light turning feature configured to direct light propagating in the light guide out of the light guide.   
     
     
         8 . The device of  claim 7 , wherein the control signal is configured to control at least a portion of the output of the at least one light source. 
     
     
         9 . The device of  claim 8 , 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. 
     
     
         10 . The device of  claim 8 , 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. 
     
     
         11 . The device of  claim 8 , 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. 
     
     
         12 . The device of  claim 8 , 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. 
     
     
         13 . The device of  claim 1 , wherein the first and second light detectors comprise a photodiode. 
     
     
         14 . A method of manufacturing a lighting device, comprising:
 providing a light guide having a first edge, a second edge, and a first surface extending between the first edge and the second edge;   disposing a first light detector along the first edge of the light guide, the first light detector coupled to the 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 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; and   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 light guide based at least in part on the first signal and the second signal.   
     
     
         15 . The method of  claim 14 , wherein electrically connecting the first light detector and the second light detector includes forming 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. 
     
     
         16 . The method of  claim 14 , wherein the control signal indicates a direction of movement of the object relative to the first edge and the second edge. 
     
     
         17 . The method of  claim 14 , wherein the control signal indicates a direction of movement of the object relative to the first surface. 
     
     
         18 . The method of  claim 17 , wherein the control signal indicates a change of distance between the first surface and the object. 
     
     
         19 . The method of  claim 14 , further comprising forming at least one light gathering feature on the first surface, the at least one light gathering feature configured to direct light incident on the light guide into the light guide. 
     
     
         20 . The method of  claim 14 , further comprising disposing at least one light source along one or more edges of the light guide. 
     
     
         21 . The method of  claim 20 , further comprising forming at least one light turning feature on the light guide, the at least one light turning feature configured to direct light propagating within the light guide away from the light guide. 
     
     
         22 . A lighting device, comprising:
 a light guide having a first edge, a second edge, and a first surface extending between the first edge and the second edge, the first surface configured to receive incident light;   first means for detecting light disposed along the first edge of the light guide and coupled to the light guide to receive light propagating therein, the first light detecting means configured to produce a first signal based on an amount of light received from the light guide through the first edge;   second means for detecting light disposed along the second edge of the light guide and coupled to the light guide to receive light propagating therein, the second light detecting means configured to produce a second signal based on an amount of light received from the light guide through the second edge; and   means for detecting a direction of movement of an object relative to the light guide, the movement detecting means including the first light detecting means and the second light detecting means and being configured to produce a control signal indicating the detected direction of movement of the object based at least in part on the first signal and the second signal.   
     
     
         23 . The lighting device of  claim 22 , wherein the first light detecting means includes at least one light detector, wherein the second light detecting means includes at least one light detector, and wherein the movement detecting means includes the first light detecting means and the second light detecting means.