Patent ID: 11914768
Assignee: ADHAWK MICROSYSTEMS INC.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 24:
25. An eye tracker comprising:
a scanner for steering a light signal in a Lissajous pattern over scan region, wherein the scanner comprises a micromechanical system (MEMS) device that is a two-axis device having a first actuator configured to rotate a scanning element about a first axis characterized by a first resonant frequency and a second actuator configured to rotate the scanning element about a second axis characterized by a second resonant frequency, and wherein the first actuator includes a first actuator element and a second actuator element, and further wherein the second actuator includes a third actuator element and a fourth actuator element; and
a processing system configured to:
(i) estimate the first resonant frequency based on a measurement of a first resistance of at least one of the second, third, and fourth actuator elements in response to an oscillation of the first axis induced by a first test drive applied to the first actuator element;
(ii) estimate the second resonant frequency based on a measurement of a second resistance of at least one of the first, second, and fourth actuator elements in response to an oscillation of the second axis induced by a second test drive applied to the third actuator element;
(iii) drive the first axis with a first periodic signal that is characterized by a first drive frequency;
(iv) drive the second axis with a second periodic signal that is characterized by a second drive frequency;
(v) control the first drive frequency based on the first resistance; and
(vi) control the second drive frequency based on the second resistance.