Manufacturing structure and process for compliant mechanisms

• US 9,182,587 B2
• Filed: 10/27/2009
• Issued: 11/10/2015
• Est. Priority Date: 10/27/2008
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Brosnihan, Timothy J., Andersson, Mark B.
• Primary Examiner(s): PINKNEY, DAWAYNE
• Application Number:
  US13/123,859
• Publication Number:
  US 20110255146A1
• Time in Patent Office: 2,205 Days
• Field of Search: 359/298, 359290-292, 359260-261, 359262-263, 359301-303, 359317-318, 359/223, 359/224, 359/225, 359/295, 359/198, 359/245, 359/577
• US Class Current: 1/1
• CPC Class Codes: G02B 26/00 Optical devices or arrangements for the control of light using movable or deformable optical elements control of light by modification of the optical properties of the media of the elements involved therein G02F1/00
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3433 using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices using liquid crystal devices G09G3/36; using electrochromic devices G09G3/38

Abstract

The invention relates, in various aspects, to systems and methods for MEMS actuated displays that can be driven at high speeds and at low voltages for improved image quality and reduced power consumption.

Claims

1. A MEMS device comprising:

a substrate; and

a first beam having a height to width aspect ratio of at least 4;

1, wherein the first beam completely encloses the boundary of a space in a plane parallel to the plane of the substrate, and wherein at least a portion of the first beam forms at least a portion of an actuator,

wherein the height of the beam is in a direction orthogonal to the plane of the substrate and the width of the beam is in a direction parallel to the plane of the substrate.

2. The MEMS device of claim 1, wherein the first beam forms a loop.

3. The MEMS device of claim 1, comprising a mechanical light modulator supported over a substrate by the first beam.

4. The MEMS device of claim 1, comprising a mechanical light modulator, wherein the actuator is configured for moving the mechanical light modulator to modulate light.

5. The MEMS device of claim 4, wherein the first beam is a compliant beam.

6. The MEMS device of claim 1, comprising an anchor connecting the first beam to the substrate.

7. The MEMS device of claim 1, comprising a second beam, wherein the first and second beam enclose respective, non-intersecting spaces.

8. The MEMS device of claim 1, comprising a second beam, wherein the second beam encloses a space that is completely enclosed by the first beam.

9. The MEMS device of claim 1, wherein the width of the first beam is no greater than 2 microns.

10. The MEMS device of claim 1 further comprising a plurality of beams with height to width aspect ratios of at least 4:

1, wherein each of the beams completely encloses the boundary of respective spaces.

11. A method of manufacturing a MEMS device, comprising:

forming a first beam to have a height to width aspect ratio of at least 4;

1, coupled to the substrate such that the first beam completely encloses the boundary of a space within a plane parallel to the plane of the substrate, and such that at least a portion of the first beam forms at least a portion of an actuator,

wherein the height of the beam is in a direction orthogonal to the plane of the substrate and the width of the beam is in a direction parallel to the plane of the substrate.

12. The method of claim 11, wherein forming the first beam comprises:

depositing a mold material onto a sacrificial layer;

etching a shape into the mold material to form a mold having at least one sidewall and at least one lower horizontal surface;

depositing material onto the etched mold such that the deposited material adheres to at least the side walls and the lower horizontal surface of the etched mold;

etching away a portion of the deposited material to remove the deposited material from the lower horizontal surface while leaving substantially all of the material deposited on the sidewalls intact; and

removing the mold such that material remaining on the sidewalls forms the first beam.

13. The method of claim 12, wherein the sidewalls comprise walls of a mesa formed in the mold, and the first beam encloses the mesa.

14. The method of claim 12, wherein the sidewalls comprise walls of a recess formed in the mold, and the first beam encloses the recess.

15. The method of claim 12, wherein the mold material is deposited on top of a layer of sacrificial material, the method further comprising removing the sacrificial material to release the first beam.

16. The method of claim 12, wherein the mold further comprises an upper horizontal surface, and the material deposited on the mold adheres to the upper horizontal surface, the method further comprising:

applying a mask to the upper horizontal surface prior to etching away the deposited material such that a portion of the material deposited on the upper horizontal surface remains on the upper horizontal surface after the etch to form a mechanical light modulator.

17. The method of claim 16, further comprising, prior to etching the shape into the mold, etching anchor holes into the mold material, and wherein the material deposited onto the mold fills the anchor holes to form anchors.

18. The method of claim 17, wherein formation of the anchors, first beam, and the mechanical light modulator requires the utilization of no more than three photolithographic masks.

19. The method of claim 12, wherein the MEMS device comprises a mechanical light modulator and an anchor, and the first beam supports the mechanical light modulator over a substrate and connects the mechanical light to the substrate via the anchor, the method comprising utilizing no more than three photolithographic masks.