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US 2018/0321483 A1Published application
Opening angle stabilization of micromirrors through current drive control
AssigneeSTMicroelectronics S.r.l.
InventorElik Haran
Life of this patent
Estimating the term…
Abstract
An electronic device disclosed herein includes a mirror controller configured to generate a drive control signal, with a drive circuit configured to generate a drive signal for a movable mirror based upon the drive control signal. A sensing circuit is configured to sense the drive signal. The mirror controller is further configured to adjust the drive control signal as a function of the sensed drive signal.
Claims21
An electronic device, comprising:
- a mirror controller configured to generate a drive control signal;
- a drive circuit configured to generate a drive signal for a movable mirror based upon the drive control signal to cause the movable mirror to oscillate between first and second predefined travel limits which define an opening angle of the movable mirror;
- and
- a sensing circuit configured to sense the drive signal;
- wherein the mirror controller is further configured to adjust the drive control signal as a function of the sensed drive signal so as to adjust the opening angle to match a desired opening angle.
2 more elements
A portable electronic device, comprising:
- an oscillating MEMS mirror that is electromagnetically operated;
- a mirror controller configured to generate a drive control signal;
- a drive circuit configured to generate a drive current for the oscillating MEMS mirror based upon the drive control signal to cause the oscillating MEMS mirror oscillate between first and second predefined travel limits which define an opening angle of the oscillating MEMS mirror;
- a sensing circuit configured to sense the drive current;
- and
- wherein the mirror controller is further configured to:
- in a calibration mode, correlate drive current to the opening angle of the oscillating MEMS mirror;
- and
- in a normal operation mode, adjust the drive control signal based upon the sensed drive current so that the opening angle of the oscillating MEMS mirror matches an expected opening angle of the oscillating MEMS mirror.
6 more elements
A method, comprising:
- driving a movable MEMS mirror with a drive current to cause the movable MEMS mirror to oscillate between first and second predefined travel limits which define an opening angle of the movable MEMS mirror;
- sensing the drive current;
- and
- where the drive current is not equal to a desired drive current, adjusting the driving of the movable MEMS mirror such that the drive current is equal to the desired drive current to thereby adjust the opening angle to match a desired opening angle.
1 more element
An electronic device, comprising:
- a mirror controller;
- a drive circuit receiving input from the mirror controller and providing output to a movable mirror to cause the movable mirror to oscillate between first and second predefined travel limits which define an opening angle of the movable mirror;
- a current to voltage converter having an input coupled to receive the output of the drive circuit;
- and
- an analog to digital converter having an input coupled to receive output from the current to voltage converter and providing output to the mirror controller for use as feedback to cause the mirror controller to adjust the opening angle to match a desired opening angle.
2 more elements
A method, comprising:
- driving a movable MEMS mirror with a drive current to cause the movable MEMS mirror to oscillate between first and second predefined travel limits which define an opening angle of the movable MEMS mirror;
- sensing the drive current;
- where the drive current is not equal to a desired drive current, adjusting the driving of the movable MEMS mirror such that the drive current is equal to the desired drive current to thereby adjust the opening angle such that the opening angle is intended to match a desired opening angle;
- and
- adjusting the desired drive current as a function of at least one mechanical property of the movable MEMS mirror.
2 more elements
Dependencies are inferred from the claim text.