Patent ID: 11940293
Assignee: APPLE INC.
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 10:
11. The finger device defined in claim 1, wherein the self-mixing interferometric proximity sensor comprises a vertical cavity surface emitting laser and a photodiode, wherein the control circuitry includes sensing circuitry that is configured to determine the changes in the distance between the self-mixing interferometric proximity sensor and the side of the finger, and wherein the sensing circuitry comprises:
a transimpedance amplifier coupled to the photodiode;
an analog-to-digital converter coupled to an output of the transimpedance amplifier;
demodulation and offset circuitry coupled to an output of the analog-to-digital converter, wherein the demodulation and offset circuitry outputs an I signal and a Q signal; and
processing circuitry configured to determine displacement based on the I signal and the Q signal.