Mems mirror driven by dual pulse drive signal
AssigneeSTMicroelectronics S.r.l.
InventorsSivan Kinstlich, Offir Duvdevany
Life of this patent
Estimating the term…
Abstract
Described herein is a device including mirror control circuitry for controlling a movable mirror. The mirror control circuitry includes drive circuitry for providing a drive signal to the movable mirror, and a processor. The processor cause the drive circuitry to generate the drive signal so as to have pulses with leading edges occurring an offset period of time after a maximum opening angle of the movable mirror and trailing edges occurring an offset period of time before a zero crossing of the movable mirror. The processor may sample a mirror sense signal from the movable mirror at times at which a derivative of capacitance of the movable mirror with respect to time is zero, and then perform an action based upon the samples.
Claims21
A device, comprising:
- mirror control circuitry for controlling a movable mirror, the mirror control circuitry comprising:
- drive circuitry for providing a drive signal to the movable mirror;
- a processor configured to:
- cause the drive circuitry to generate the drive signal so as to have pulses associated with times at which a derivative of capacitance of the movable mirror with respect to time is zero.
A method of driving a movable mirror, comprising:
- generate a drive signal for the movable mirror so as to have a respective different pulse generated an offset period of time after each time at which an opening angle of the movable mirror is at a maximum or minimum;
- sample a mirror sense signal from the movable mirror at least twice during each period of the drive signal;
- and
- perform at least one action as a function of the sampled mirror sense signal.
A device, comprising:
- mirror control circuitry for controlling a movable mirror, the mirror control circuitry comprising:
- drive circuitry for providing a drive signal to the movable mirror;
- and
- a processor configured to cause the drive circuitry to generate the drive signal so as to have a frequency that is twice a frequency of oscillation of the movable mirror but does not have pulses occurring at times at which a derivative of capacitance of the movable mirror with respect to time is zero.
A device, comprising:
- mirror control circuitry for controlling an oscillating mirror, the mirror control circuitry comprising:
- drive circuitry for providing a drive signal to the oscillating mirror;
- and
- a processor configured to cause the drive circuitry to generate the drive signal so as to have a duty cycle that is less than one quarter of a period of oscillation of the oscillating mirror and has pulses with leading edges offset from a maximum opening angle of the oscillating mirror and trailing edges offset from a zero crossing of the opening angle of the oscillating mirror.
A method, comprising:
- generating a drive signal for an oscillating mirror;
- and
- wherein the drive signal is generated to have a duty cycle that is less than one quarter of a period of oscillation of the oscillating mirror and has pulses with leading edges offset from a maximum opening angle of the oscillating mirror and trailing edges offset from a zero crossing of the opening angle of the oscillating mirror.
The method of claim 21, further comprising determining at least one property of the oscillating mirror as a function of the first and second samples.
Dependencies are inferred from the claim text.