System and method for driving a two-axis scanning mirror using drivers of different types

Patent metadata

Field	Value
Publication number	US-12306399-B2
Application number	US-202117172047-A
Country	US
Kind code	B2
Filing date	Feb 9, 2021
Priority date	Feb 9, 2021
Publication date	May 20, 2025
Grant date	May 20, 2025

Abstract

Embodiments of the disclosure provide a scanner for steering optical beams. In certain configurations, the scanner may include a scanning mirror independently rotatable around a first axis and a second axis. In certain other configurations, the scanner may also include a first driver configured to drive the scanning mirror to rotate around the first axis. In still other configurations, the scanner may further include a second driver configured to drive the scanning mirror to simultaneously rotate around the second axis. In certain aspects, the first driver and the second driver may be different types of drivers.

First claim

What is claimed is:

1. A scanner for steering optical beams, comprising:
a scanning mirror independently rotatable around a first axis and a second axis;
a first driver that is an electrostatic driver configured to drive the scanning mirror to rotate around the first axis at a first frequency that is twice a natural oscillation frequency of the scanning mirror;
a gimbal connected to the electrostatic driver, wherein the scanning mirror and the gimbal are simultaneously formed from a same silicon material; and
a second driver that is a piezoelectric driver configured to drive the scanning mirror to simultaneously rotate around the second axis.

2. The scanner of claim 1 , wherein the scanning mirror, the first driver, and the second driver are formed on single crystal silicon.

3. The scanner of claim 1 , wherein:
the piezoelectric driver is configured to oscillate the scanning mirror around the second axis at a second frequency, and
the first frequency is higher than the second frequency.

4. The scanner of claim 1 , wherein:
the electrostatic driver comprises a pair of parallel plate drive electrodes configured to alternately pull or push sides of the scanning mirror, or
the electrostatic driver comprises a pair of comb drivers attached to opposite edges of the scanning mirror.

5. The scanner of claim 1 , wherein the electrostatic driver is configured to oscillate the scanning mirror around the first axis by an application of a driving voltage with a sinusoidal waveform.

6. The scanner of claim 4 , wherein a first set of comb fingers of each comb driver are attached to the gimbal and a second set of comb fingers of each comb driver are attached to the scanning mirror.

7. The scanner of claim 6 , further comprising:
an isolation trench formed in the gimbal and configured to electrically isolate the scanning mirror from the gimbal.

8. The scanner of claim 6 , wherein the piezoelectric driver includes a plurality of piezoelectric films formed on a portion of a silicon beam adjacent to the gimbal.

9. The scanner of claim 8 , further comprising:
a plurality of anchors;
at least one first torsion spring positioned along the first axis; and
at least one second torsion spring positioned along the second axis,
wherein the at least one first torsion spring is coupled to at least one of the plurality of anchors and the scanning mirror, and
wherein the at least one second torsion spring is coupled to the silicon beam and a gimbal.

10. The scanner of claim 8 , wherein:
the piezoelectric driver includes a plurality of electrodes each formed between a corresponding one of the plurality of piezoelectric films and the silicon beam, and
the plurality of electrodes are configured to apply a potential to the plurality of piezoelectric films.

11. The scanner of claim 8 , wherein the plurality of piezoelectric films are zirconate titanate (PZT) films.

12. A transmitter for an optical sensing system, comprising:
a light source configured to emit a light beam; and
a scanner for steering the light beam towards an object, the scanner comprising:
a scanning mirror independently rotatable around a first axis and a second axis;
a first driver that is an electrostatic driver configured to drive the scanning mirror to rotate around the first axis at a first frequency that is twice a natural oscillation frequency of the scanning mirror;
a gimbal connected to the electrostatic driver, wherein the scanning mirror and the gimbal are simultaneously formed from a same silicon material; and
a second driver that is a piezoelectric driver configured to drive the scanning mirror to simultaneously rotate around the second axis.

13. The transmitter of claim 12 , wherein the scanning mirror, the first driver, and the second driver are formed on a single crystal silicon.

14. The transmitter of claim 12 , wherein:
the piezoelectric driver is configured to oscillate the scanning mirror at a second frequency, and
the first frequency is higher than the second frequency.

15. The transmitter of claim 14 , wherein a first portion of the electrostatic driver is attached to the gimbal and a
second portion of the electrostatic driver is attached to the scanning mirror.

16. The transmitter of claim 15 , wherein the scanner further comprises:
an isolation trench formed in the gimbal and configured to electrically isolate the first portion of the electrostatic driver and the second portion of the electrostatic driver.

17. A scanning method of an optical sensing system, comprising:
driving a scanning mirror to oscillate around a first axis using a first driver that is an electrostatic driver at a first frequency that is twice a natural oscillation frequency of the scanning mirror, wherein the first driver that is an electrostatic driver is connected to a gimbal and the gimbal and the scanning mirror are simultaneously formed from a same silicon material; and
driving the scanning mirror to simultaneously oscillate around a second axis using a second driver that is a piezoelectric driver,
wherein the scanning mirror, the first driver, and the second driver are formed on a single crystal silicon.

Assignees

• Beijing Voyager Tech Co Ltd

Inventors

• Wang Youmin
• Wang Yufeng
• Li Gary

Classifications

• G02B26/0841

  the reflecting element being moved or deformed by electrostatic means · CPC title

• G01S17/894

  Three-dimensional [3D] imaging with simultaneous measurement of time-of-flight at a two-dimensional [2D] array of receiver pixels, e.g. time-of-flight cameras or flash lidar · CPC title

• G01S7/4817 Primary

  relating to scanning · CPC title

• G01S17/931

  of land vehicles · CPC title

• G02B26/0858

  the reflecting means being moved or deformed by piezoelectric means · CPC title