Patent ID: 8502153

Claim:
A method of measuring and cancelling crosstalk in an optical proximity sensor that comprises an integrated circuit (IC) with a processor, the method comprising: emitting, from an infrared light emitter included in the sensor and operating under control of and operably connected to the IC, a first burst of infrared light pulses when an object to be detected is not within sensing proximity to the sensor; detecting, with a light detector included in the sensor and operating under control of and operably connected to the IC, during the first burst of light pulses a first signal corresponding to crosstalk occurring between the light emitter and the light detector; integrating and sampling the first signal; storing, in a first memory location or first register of the IC, a first value corresponding to the integrated and sampled first signal; emitting, from the infrared light emitter, a second burst of infrared light pulses when the object to be detected is within sensing proximity to the sensor; detecting, with the light detector, during the second burst of light pulses a second signal comprising a sum of the crosstalk and a proximity signal corresponding to light reflected from the object to be detected; integrating and sampling the second signal; storing, in a second memory location or second register of the IC, a second value corresponding to the integrated and sampled second signal, and subtracting the first value from the second value thereby to yield a third value corresponding to the proximity signal.