Patent ID: 8907264

Claim:
An optoelectronics apparatus for use with a single light source that is driven to selectively emit light, the optoelectronics apparatus comprising: first, second, third and fourth electrically isolated photodetector (PD) segments, each of which is configured to detect light originating from the single light source that has reflected off an object and is incident on the PD segment, wherein the first PD segment is used to produce a first signal (A) indicative of the reflected light that is incident on the first PD segment, the second PD segment is used to produce a second signal (B) indicative of the reflected light incident on the second PD segment, the third PD segment is used to produce a third signal (C) indicative of the reflected light incident on the third PD segment, and the fourth PD segment is used to produce a fourth signal (D) indicative of the reflected light incident on the fourth PD segment; circuitry configured to produce a first motion signal that is indicative of a sum of the first and second signals minus a sum of the third and fourth signals ((A+B)−(C+D)); circuitry configured to produce a second motion signal that is indicative of a sum of the second and third signals minus a sum of the first and fourth signals ((B+C)−(A+D)); circuitry configured to produce a total irradiance signal that is indicative of a sum of the first, second, third and fourth signals (A+B+C+D); circuitry configured to produce, in dependence on the first and second motion signals, a signal and/or data that is indicative of a direction of motion of an object; circuitry configured to produce, in dependence on the first and second motion signals, a signal and/or data that is indicative of a rate of motion of an object; and circuitry configured to distinguish between an active stroke motion of an object and a retrace motion of an object in dependence on the signal and/or data that is indicative of a rate of motion of an object and on the total irradiance signal.