Abstract: Systems and methods for determining the resonant frequencies of at least one axis of a two-axis resonant light scanner based on a measured resistance of at least a portion of one of the axes are disclosed. Precise knowledge of the resonant frequencies of each axis enables quasi-closed-loop operation of a light scanner, wherein the resonant frequencies of its axes can be periodically updated to ensure the proper drive frequencies are used. Furthermore, by determining the relationship between the measured resistance and scanner angle, calibration of the scanner is facilitated and even enabled at the wafer level during fabrication. In some cases, it also enables real-time monitoring of scanner position. Scanners in accordance with the present disclosure are suitable for use in any application that requires one or more reflective elements that can be scanned or steered in at least one dimension.

Abstract: Systems and methods for monitoring the instantaneous position of a scanning element of a light scanner via an optical-feedback signal are disclosed, where the optical-feedback signal is a portion of a light signal being steered in a two-dimensional pattern by the light scanner. The optical-feedback signal is detected by a position monitor that provides a commensurate feedback signal. In some embodiments, the feedback signal is used to develop a transfer function for the light scanner via a calibration routine. In some embodiments, the feedback signal is used in a closed-loop driving scheme used to drive the light scanner. Embodiments in accordance with the present disclosure are particularly well suited for use in object tracking systems, such as eye trackers.

Abstract: Systems and methods for determining the resonant frequencies of at least one axis of a two-axis resonant light scanner based on a measured resistance of at least a portion of one of the axes are disclosed. Precise knowledge of the resonant frequencies of each axis enables quasi-closed-loop operation of a light scanner, wherein the resonant frequencies of its axes can be periodically updated to ensure the proper drive frequencies are used. Furthermore, by determining the relationship between the measured resistance and scanner angle, calibration of the scanner is facilitated and even enabled at the wafer level during fabrication. In some cases, it also enables real-time monitoring of scanner position. Scanners in accordance with the present disclosure are suitable for use in any application that requires one or more reflective elements that can be scanned or steered in at least one dimension.