CPC G01S 17/36 (2013.01) [G01J 1/4204 (2013.01); G01S 7/4816 (2013.01); G02B 1/11 (2013.01); G02B 3/0056 (2013.01); G02B 5/20 (2013.01)] | 18 Claims |
1. An optical proximity sensor comprising:
a solid-state photo-electric converter;
a biasing circuit configured to bias the solid-state photo-electric converter; and
a control circuit, wherein the control circuit is configured to:
control the biasing circuit to apply, to the solid-state photo-electric converter, a bias signal modulated between a first value and a second value, the second value different from the first value, both the first value and the second value being higher than a breakdown voltage of the solid-state photo-electric converter, wherein a modulated optical signal is emitted by the solid-state photo-electric converter towards a target object in response to the bias signal being applied to the solid-state photo-electric converter,
receive an electrical output signal from the solid-state photo-electric converter, the electrical output signal being a function of a received modulated optical signal that is received at the solid-state photo-electric converter as a result of reflection of the modulated optical signal emitted towards the target object,
perform a phase comparison of the bias signal applied to the solid-state photo-electric converter against the electrical output signal received from the solid-state photo-electric converter,
produce a phase shift signal based on the phase comparison, the phase shift signal being a function of a phase shift between the modulated optical signal emitted towards the target object and the received modulated optical signal that is received at the solid-state photo-electric converter, and
compute a distance between the optical proximity sensor and the target object as a function of the phase shift signal.
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