MEMS electrostatic actuator with linearized displacements

Patent metadata

Field	Value
Publication number	US-11256083-B2
Application number	US-201816233812-A
Country	US
Kind code	B2
Filing date	Dec 27, 2018
Priority date	Dec 27, 2018
Publication date	Feb 22, 2022
Grant date	Feb 22, 2022

Abstract

A microelectromechanical actuator for a light beam steering device is provided that includes memory cells coupled to at least one electronic circuitry component and electrode segments coupled to a respective one of the memory cells via the at least one electronic circuitry component. A flexible metal layer having support pillars is on the electrode segments. Flexible beams are attached to the support pillars and a movable electrode attaches to the flexible beams. A mirror is attached to the movable electrode. When one or more of the electrode segments is activated, the mirror is displaced a distance to steer a light beam output from a light source in a direction.

First claim

What is claimed is:

1. A device comprising:
a substrate comprising:
a first memory cell;
a second memory cell; and
an electronic circuit coupled to the first memory cell and to the second memory cell;

a fixed electrode layer on the substrate, the fixed electrode layer comprising:
a first electrode segment coupled to the first memory cell via the electronic circuit; and
a second electrode segment coupled to the second memory cell via the electronic circuit, the second electrode segment surrounding the first electrode segment;

a movable electrode layer on the fixed electrode layer; and
a mirror layer on the movable electrode layer, the mirror layer comprising a mirror.

2. The device of claim 1 , wherein the fixed electrode layer further comprises a bias electrode segment surrounding the second electrode segment.

3. The device of claim 2 , wherein the fixed electrode layer further comprises a third electrode segment surrounding the second electrode segment, the bias electrode segment surrounding the third electrode segment.

4. The device of claim 3 , wherein the first electrode segment has a first area, the second electrode segment has a second area, and the third electrode segment has a third area, wherein a sum of the first area, the second area, and the third area is an electrode area, wherein the first area is 19% the electrode area, the second area is 24% the electrode area, and the third area is 57% the electrode area.

5. The device of claim 1 , wherein the first electrode segment is symmetrical along a first axis and a second axis, the second axis orthogonal to the first axis, and the second electrode segment is symmetrical along the first axis and the second axis.

6. The device of claim 1 , wherein the first electrode segment is square.

7. The device of claim 1 , wherein the first electrode segment is X-shaped.

8. The device of claim 1 , wherein responsive to a first value of the first memory cell and a second value of the second memory cell, the mirror is a first distance from the fixed electrode layer, a second distance from the fixed electrode layer, or a third distance from the fixed electrode layer, wherein a first difference between the first distance and the second distance is approximately the same as a second difference between the second distance and the third distance.

9. The device of claim 8 , wherein the first electrode segment has a first applied voltage and the second electrode segment has a second applied voltage, the second applied voltage different from the first applied voltage.

10. A device comprising:
a substrate comprising:
a first memory cell; and
a second memory cell;

a fixed electrode layer on the substrate, the fixed electrode layer comprising:
a first electrode segment coupled to the first memory cell, the first memory cell configured to apply a first voltage to the first electrode segment; and
a second electrode segment coupled to the second memory cell, the second memory cell configured to apply a second voltage to the second electrode segment;

a movable electrode layer on the fixed electrode layer; and
a mirror layer on the movable electrode layer, the mirror layer comprising a mirror, wherein responsive to the first memory cell and the second memory cell, the mirror is a first distance from the fixed electrode layer, a second distance from the fixed electrode layer, or a third distance from the fixed electrode layer, wherein a first difference between the first distance and the second distance is approximately the same as a second difference between the second distance and the third distance.

11. The device of claim 10 , wherein responsive to the first memory cell and the second memory cell, the mirror is a fourth distance from the fixed electrode layer, wherein a third difference between the fourth distance and the third distance is approximately the same as the first distance.

12. The device of claim 10 , wherein the second electrode segment surrounds the first electrode segment.

13. The device of claim 12 , the fixed electrode layer further comprising a bias electrode segment surrounding the second electrode segment.

14. The device of claim 13 , the fixed electrode layer further comprising a third electrode segment, the third electrode segment surrounding the second electrode segment and the bias electrode segment surround the third electrode segment.

15. The device of claim 10 , wherein the first electrode segment is symmetrical along a first axis and a second axis, the second axis orthogonal to the first axis, and the second electrode segment is symmetrical along the first axis and the second axis.

16. A system comprising:
a controller; and
a microelectromechanical system (MEMS) device coupled to the controller, the MEMS device comprising:
a substrate comprising:
a first memory cell coupled to the controller, the controller configured to load a first value or a second value in the first memory cell; and
a second memory cell coupled to the controller, the controller configured to load the first value or the second value in the second memory cell;

a fixed electrode layer on the substrate, the fixed electrode layer comprising:
a first electrode segment coupled to the first memory cell, the first memory cell configured to apply a first voltage to the first electrode segment; and
a second electrode segment coupled to the second memory cell, the second memory cell configured to apply a second voltage to the second electrode segment;

a movable electrode layer on the fixed electrode layer; and
a mirror layer on the movable electrode layer, the mirror layer comprising a mirror, wherein responsive to the first memory cell and the second memory cell, the mirror is a first distance from the fixed electrode layer, a second distance from the fixed electrode layer, or a third distance from the fixed electrode layer, wherein a first difference between the first distance and the second distance is approximately the same as a second difference between the second distance and the third distance.

17. The system of claim 16 , further comprising a light source coupled to the controller, the light source optically coupled to the mirror.

18. The system of claim 16 , wherein the second electrode segment surrounds the first electrode segment.

19. The system of claim 18 , wherein the fixed electrode layer further comprises:
a third electrode segment surrounding the second electrode segment; and
a bias electrode surrounding the third electrode segment.

20. The system of claim 16 , wherein the first electrode segment has a first applied voltage and the second electrode segment has a second applied voltage, the second applied voltage different from the first applied voltage.

Assignees

• Texas Instruments Inc

Inventors

• Mcdonald William Craig
• Hall James Norman

Classifications

• H02N1/006

  of the gap-closing type (H02N1/004 takes precedence) · CPC title

• G02B26/0841 Primary

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