Optical proximity sensors with reconfigurable photo diode array

Abstract

Optical proximity sensors, methods for use therewith, and systems including optical proximity sensor are described herein. Such an optical proximity sensor includes a light source and a light detector, wherein the light detector includes a plurality of individually selectable photodiodes (PDs). During a calibration mode, individual PDs of the plurality of PDs of the light detector are tested to identify which PDs are crosstalk dominated. During an operation mode, the PDs of the light detector that were not identified as being crosstalk dominated are used to produce a light detection value or signal that is useful for detecting the presence, proximity and/or motion of an object within the sense region of the optical proximity sensor. By not using the PDs that were identified as being crosstalk dominated, the signal-to-noise ratio of the light detection value or signal is improved compared to if the crosstalk dominated PDs were also used.

What is claimed is: 
     
         1 . A method for use with an optical proximity sensor, including a light source and a light detector, wherein the light detector includes a plurality of photodiodes (PDs), the method comprising:
 during a calibration mode of the optical proximity sensor, identifying certain PDs of the plurality of PDs of the light detector are optical crosstalk dominated; and   during an operation mode of the optical proximity sensor that is separate from the calibration mode, using other of the PDs of the light detector that were not identified as being optical crosstalk dominated, and not using the certain PDs of the light detector that were identified as being optical crosstalk dominated, to produce a light detection signal.   
     
     
         2 . The method of  claim 1 , wherein the light detection signal is useful for detecting the presence, proximity and/or motion of an object within the sense region of the optical proximity sensor. 
     
     
         3 . The method of  claim 1 , wherein the calibration mode includes:
 driving the light source to emit light while there is no object within a sense region of the optical proximity sensor and/or the light detector is covered by an opaque material;   selecting each of the PDs one at a time, while the light source is emitting light, to thereby determine and store a value for each of the PDs that is indicative of the amount of light detected by the PD; and   identifying, based on the stored values, which individual PDs of the plurality of PDs of the light detector are optical crosstalk dominated.   
     
     
         4 . The method of  claim 3 , wherein identifying certain PDs of the plurality of PDs of the light detector are optical crosstalk dominated comprises:
 comparing the stored values to a threshold value; and   identifying, as being optical crosstalk dominated, each of the PDs whose stored value exceeds the threshold.   
     
     
         5 . The method of  claim 4 , wherein the threshold is a predetermined fixed value or a programmable value. 
     
     
         6 . The method of  claim 4 , further comprising:
 determining a value that corresponds to a dark current produced by a PD of the light detector; and   determining the threshold value based on the value that corresponds to the dark current.   
     
     
         7 . The method of  claim 1 , wherein the operational mode includes deactivating or ignoring the certain PDs that were identified, during the calibration mode, as being optical crosstalk dominated. 
     
     
         8 . The method of  claim 1 , wherein the operational mode includes:
 driving the light source to emit light;   selecting each of the other PDs of the light detector one at a time, while the light source is emitting light, to thereby determine and store a value for each of the other PDs of the light detector that is indicative of the amount of light detected by the PD; and   adding the values stored for each of the other PDs that were not identified as being optical crosstalk dominated to thereby produce a light detection value that is useful for detecting the presence, proximity and/or motion of an object within the sense region of optical proximity sensor.   
     
     
         9 . The method of  claim 1 , wherein the operational mode includes:
 driving the light source to emit light;   selecting each of the other PDs that were not identified as being optical crosstalk dominated one at a time, while the light source is emitting light, to thereby determine and store a value for each of the other PDs that were not identified as being optical crosstalk dominated, wherein the value is indicative of the amount of light detected by the PD; and   adding the values stored for each of the other PDs that were not identified as being optical crosstalk dominated to thereby produce a light detection value that is useful for detecting the presence, proximity and/or motion of an object within the sense region of optical proximity sensor.   
     
     
         10 . The method of  claim 1 , wherein the operational mode includes:
 connecting together each of the other PDs that were not identified as being optical crosstalk dominated;   driving the light source to emit light; and   while the light source is emitting light, using the connected other PDs that were not identified as being optical crosstalk dominated to produce a light detection signal that is useful for detecting the presence, proximity and/or motion of an object within the sense region of optical proximity sensor, wherein the light detection signal is indicative of the amount of light detected by connected together other PDs.   
     
     
         11 . The method of  claim 1 , further comprising:
 during the operational mode, using the light detection signal to detect the presence, proximity and/or motion of an object within the sense region of the optical proximity sensor; and   during the operational mode, selecting a response or action in dependence on the presence, proximity and/or motion of the object within the sense region of the optical proximity sensor.   
     
     
         12 . An optical proximity sensor, comprising:
 a light source that is selectively driven to emit light;   a light detector including a plurality of photodiodes (PDs); and   a controller configured to identify, during a calibration mode, certain PDs of the plurality of PDs of the light detector are optical crosstalk dominated, and cause, during an operational mode, a light detection signal to be produced using the other of the PDs of the light detector that were not identified as being optical crosstalk dominated, and not using the certain PDs of the light detector that were identified as being optical crosstalk dominated   
     
     
         13 . The optical proximity sensor of  claim 12 , further comprising an opaque barrier between the light source and the light detector. 
     
     
         14 . The optical proximity sensor of  claim 12 , further comprising:
 a driver that selectively drives the light source to emit light; and   memory or registers;   wherein the controller is configured to, during the calibration mode cause the light source to be driven by the driver to emit light, cause each of the PDs to be selected one at a time while the light source is emitting light, to thereby determine and store in the memory or registers a value for each of the PDs that is indicative of the amount of light detected by the PD; and   identify, based on the stored values, the certain PDs of the plurality of PDs of the light detector are optical crosstalk dominated.   
     
     
         15 . The optical proximity sensor of  claim 14 , wherein the controller is configured to, during the calibration mode, compare the stored values to a threshold value, and identify as being optical crosstalk dominated each of the PDs whose stored value exceeds the threshold. 
     
     
         16 . The optical proximity sensor of  claim 12 , wherein the controller is configured to, during the operational mode, cause the light source to be driven to emit light;
 cause each of the other PDs of the light detector to be individually selected one at a time, while the light source is emitting light, to thereby determine and store a value for each of the other PDs of the light detector that is indicative of the amount of light detected by the PD; and   add the values stored for each of the other PDs that were not identified as being optical crosstalk dominated to thereby produce a light detection value that is useful for detecting the presence, proximity and/or motion of an object within the sense region of optical proximity sensor.   
     
     
         17 . The optical proximity sensor of  claim 12 , wherein the controller is configured to, during the operational mode, cause the light source to be driven to emit light;
 cause each of the other PDs of the light detector that were not identified as being optical crosstalk dominated to be individually selected one at a time, while the light source is emitting light, to thereby determine and store a value for each of the other PDs of the light detector that were not identified as being optical crosstalk dominated, wherein the value is indicative of the amount of light detected by the PD; and   add the values stored for each of the other PDs that were not identified as being optical crosstalk dominated to thereby produce a light detection value that is useful for detecting the presence, proximity and/or motion of an object within the sense region of optical proximity sensor.   
     
     
         18 . The optical proximity sensor of  claim 12 , wherein the controller is configured to, during the operational mode, cause the light source to be driven to emit light;
 cause each of the other PDs that were not identified as being optical crosstalk dominated to be connected together so that the connected together other PDs that were not identified as being optical crosstalk dominated can be used to produce a light detection signal that is useful for detecting the presence, proximity and/or motion of an object within the sense region of optical proximity sensor, wherein the light detection signal is indicative of the amount of light detected by connected together other PDs.   
     
     
         19 . A system, comprising:
 a light source that is selectively driven to emit light;   a driver to selectively drive the light source;   a light detector including a plurality of photodiodes (PDs); and   a controller configured to identify, during a calibration mode, certain PDs of the plurality of PDs of the light detector are optical crosstalk dominated, and cause, during an operational mode, a light detection value or signal to be produced using other of the PDs of the light detector that were not identified as being optical crosstalk dominated, and not using the certain PDs of the light detector that were identified as being optical crosstalk dominated.   
     
     
         20 . The system of  claim 19 , further comprising:
 a subsystem capable of being enabled and disabled; and   a comparator or processor that receives the light detection value or signal and selectively enables or disables the subsystem in dependence thereon,   wherein the subsystem is at least one of:   a touch-screen,
 a display, 
 a backlight, 
 a virtual scroll wheel, 
 a virtual keypad, 
 a navigation pad, 
 a camera, 
 a sensor, 
 a central processing unit (CPU), or 
 a mechanical actuator.