Electromechanical systems device with hinges for reducing tilt instability

• US 9,715,102 B2
• Filed: 06/11/2015
• Issued: 07/25/2017
• Est. Priority Date: 06/11/2015
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Inventors: Lin, Hung-Yi, Lee, Bor-Shiun, Lee, Chih-Chun, Hsiao, Sheng-Yi
• Primary Examiner(s): THOMAS, BRANDI N
• Application Number:
  US14/737,101
• Publication Number:
  US 20160363761A1
• Time in Patent Office: 775 Days
• Field of Search: 359290, 359291, 359295, 359298, 359237, 359245, 359251, 359252, 359254, 359266, 359269, 359270, 359271, 345108, 345103, 345 98, 345 85, 345 30
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G06F 3/01 Input arrangements or combined input and output arrangements for interaction between user and computer G06F3/16 takes precedence
• CPC Class Codes: G06T 1/20 Processor architectures; Processor configuration, e.g. pipelining
• CPC Class Codes: G09G 5/00 Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators image data processing or generation, in general G06T

Abstract

This disclosure provides systems, methods, and apparatus for reducing tilt instability in an electromechanical systems (EMS) device, where the EMS device includes a plurality of hinges supporting a movable mirror over a stationary electrode and having identical hinge lengths. The EMS device can include a plurality of first anchor points providing connection at the substrate and a plurality of second anchor points providing connection at the movable mirror. Each of the hinges can be positioned between paired first and second anchor points and symmetrically arranged about the center of the movable mirror. In some implementations, the plurality of first anchor points and the plurality of second anchor points can be defined by a single mask.

Claims

1. An electromechanical systems (EMS) device comprising:

a substrate;

a stationary electrode on the substrate;

a movable mirror over the stationary electrode and configured to move across a first gap by electrostatic actuation between the movable mirror and the stationary electrode;

a plurality of first anchor points equally spaced apart and arranged about the center of the movable mirror, the first anchor points providing connection of the EMS device at the substrate;

a plurality of second anchor points equally spaced apart and arranged about the center of the movable mirror, the second anchor points providing connection of the EMS device at the movable mirror, each of the first anchor points corresponding to at least one of the second anchor points to define a plurality of paired first and second anchor points; and

a plurality of hinges, each positioned between a distinct one of the plurality of paired first and second anchor points, the plurality of hinges connected to the movable mirror and symmetrically arranged about the center of the EMS device, wherein the movable mirror has a front surface facing the substrate and a back surface opposite the front surface, the plurality of hinges suspended over and connected to the back surface of the movable mirror at the plurality of second anchor points.

2. The device of claim 1, wherein each of the hinges has identical or at least substantially identical hinge lengths.

3. The device of claim 1, wherein each of the plurality of hinges comprises:

a first metal layer;

a second metal layer over the first metal layer; and

a dielectric layer between the first metal layer and the second metal layer.

4. The device of claim 1, further comprising:

one or more movable posts, each of the movable posts including a protrusion configured to contact the stationary electrode during electrostatic actuation before the movable mirror contacts the stationary electrode, the one or more movable posts having a tapered profile.

5. The device of claim 4, wherein the one or more movable posts are connected to the movable mirror at a periphery of the movable mirror.

6. The device of claim 1, wherein at least part of each of the plurality of hinges and the movable mirror are coplanar.

7. The device of claim 1, further comprising:

one or more reinforcing layers connecting the hinges to the substrate at the plurality of first anchor points, and connecting the hinges to the movable mirror at the plurality of second anchor points.

8. The device of claim 1, wherein the plurality of hinges are connected to the substrate at the plurality of first anchor points.

9. The device of claim 1, further comprising:

a top plate over the movable mirror, wherein the top plate and the movable mirror define a second gap therebetween.

10. The device of claim 9, wherein the top plate has substantially the same composition and thickness as the plurality of hinges.

11. The device of claim 9, wherein the movable mirror is configured to move across the second gap by electrostatic actuation between the movable mirror and the top plate.

12. The device of claim 9, further comprising:

a stiffening layer disposed on the top plate, wherein a thickness of the stiffening layer is greater than a thickness of the top plate.

13. The device of claim 9, further comprising:

a plurality of smaller hinges connecting the top plate to the substrate at the first anchor points.

14. The device of claim 9, wherein the plurality of hinges are positioned around a periphery of the top plate.

15. The device of claim 1, wherein the plurality of hinges are connected at the second anchor points at the outermost areas of the movable mirror from the center of the movable mirror.

16. The device of claim 1, further comprising:

a support frame connected to the substrate at the plurality of first anchor points, the support frame around a periphery of the movable mirror.

17. The device of claim 16, wherein the plurality of hinges are connected to the support frame and connected to the back surface of the movable mirror at the plurality of second anchor points.

18. The device of claim 1, wherein the EMS device forms a display in a system, the system further comprising:

a processor that is configured to communicate with the display, the processor being configured to process image data;

a memory device that is configured to communicate with the processor;

a driver circuit configured to send at least one signal to the display; and

a controller configured to send at least a portion of the image data to the driver circuit;

an image source module configured to send the image data to the processor, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter; and

an input device configured to receive input data and to communicate the input data to the processor.