MEMS devices for smart lighting applications

Patent metadata

Field	Value
Publication number	US-10451808-B2
Application number	US-201615747247-A
Country	US
Kind code	B2
Filing date	Jul 22, 2016
Priority date	Jul 24, 2015
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

The invention provides a device comprising a movable micromirror adapted to receive light from one or more light source(s) and manipulate the reflected light. The micromirror can be actuated electrothermally. In particular, the micromirror is adapted to do at least one of: (a) tipping along a first axis; (b) tilting along a second axis; (c) changing focal length (i.e., varifocal mode); and (d) elevating (i.e., piston mode). The invention also provides a system comprising at least one device comprising a movable micromirror and at least one light source. The invention can be used in smart lighting applications.

First claim

What is claimed is:

1. A device comprising:
a base substrate;
a platform suspended over the base substrate;
a plurality of support elements supporting the platform over the base substrate, wherein each support element has a first end and a second end, wherein the first end of each support element is mounted on the base substrate and connected to an electrical source, and wherein the second end of each support element is suspended over the base substrate, the plurality of support elements being configured to cause the platform to move relative to the base substrate; and
a micromirror including a first portion directly attached to the platform such that the first portion cannot move relative to the platform and a second portion that is not attached to the platform such that the second portion can move relative to the platform, the micromirror including a material that is configured to enable the second portion of the micromirror to move relative to the platform responsive to an input.

2. The device of claim 1 , further comprising a plurality of spring elements, wherein each spring element has a first end and a second end, and wherein the first end of each spring element is connected to the second end of each support element, and wherein the second end of each spring element is connected to the platform.

3. The device of claim 1 , wherein each support element includes a multimorph material movable in response to an electrical signal.

4. The device of claim 1 , wherein the plurality of support elements are configured to enable the platform to (i) tip along a first axis; (ii) tilt along a second axis; (iii) elevate relative to the base substrate, or (iv) any combination of (i)-(iii).

5. The device of claim 4 , wherein the tipping of the platform along the first axis, the tilting of the platform along the second axis, or both has a range of −20 degrees to +20 degrees.

6. The device of claim 1 , wherein the movement of the second portion of the micromirror relative to the platform responsive to the input causes a change in (i) a curvature of the micromirror, (ii) a focal length of the micromirror, or (iii) both (i) and (ii).

7. The device of claim 4 , wherein the plurality of support elements is configured to elevate the platform relative to the base substrate by about 300 μm.

8. The device of claim 3 , wherein each support element comprises a first layer comprising polysilicon, and a second layer comprising gold, wherein the second layer is disposed on top of the first layer.

9. The device of claim 8 , further comprising an adhesion layer comprising chromium or titanium disposed between the first layer and the second layer.

10. The device of claim 2 , wherein each of the plurality of spring elements is stretchable.

11. The device of claim 2 , wherein each of the plurality of spring elements has a serpentine shape.

12. The device of claim 2 , wherein each of the plurality of spring elements comprises a semiconductor or metal.

13. The device of claim 12 , wherein each of the plurality of spring elements comprises polysilicon.

14. The device of claim 12 , wherein each of the plurality of spring elements comprises an alloy.

15. The device of claim 1 , wherein the platform has a shape selected from the group consisting of circular, oval, square, rectangular, pentagonal, and hexagonal.

16. The device of claim 1 , wherein the platform comprises a semiconductor or metal.

17. The device of claim 16 , wherein the platform comprises polysilicon or single crystalline silicon.

18. The device of claim 1 , wherein the first portion of the micromirror includes a center of the micromirror and the second portion surrounds the first portion.

19. The device of claim 1 , wherein the micromirror comprises a plurality of segments.

20. The device of claim 1 , wherein the micromirror comprises a first layer comprising polysilicon, and a second layer comprising gold, wherein the second layer is disposed on top of the first layer.

21. The device of claim 20 , further comprising an adhesion layer comprising chromium or titanium disposed between the first layer and the second layer.

22. The device of claim 1 , further comprising a heating element positioned underneath the platform and adapted to heat up the micromirror.

23. An optical network switch system comprising:
a switch backplane;
a base substrate supported by the switch backplane;
a platform suspended over the base substrate;
a plurality of support elements supporting the platform over the base substrate, wherein each support element has a first end and a second end, wherein the first end of each support element is mounted on the base substrate and connected to an electrical source, and wherein the second end of each support element is suspended over the base substrate, the plurality of support elements being configured to cause the platform to move relative to the base substrate;
a micromirror including a first portion directly attached to the platform such that the first portion cannot move relative to the platform and a second portion that is not attached to the platform such that the second portion can move relative to the platform, the micromirror including a material that is configured to enable the second portion of the micromirror to move relative to the platform responsive to an input, the micromirror being positioned to receive an optical signal from an input optical fiber and direct the optical signal along a signal path towards an output optical fiber.

24. The optical network switch of claim 23 , wherein the plurality of micromirror devices are arranged on the switch backplane in a geometric, ordered, or random pattern.

25. The optical network switch of claim 23 , further comprising a switch controller configured to send signals to at least one of the plurality of support elements of the first one of the plurality of micromirror devices and actuate the micromirror of the first one of the plurality of micromirror devices to direct the optical signal along a predefined signal path.

26. A system comprising:
a base substrate;
a platform suspended over the base substrate;
a plurality of support elements supporting the platform over the base substrate, wherein each support element has a first end and a second end, wherein the first end of each support element is mounted on the base substrate and connected to an electrical source, and wherein the second end of each support element is suspended over the base substrate, the plurality of support elements being configured to cause the platform to move relative to the base substrate;
a micromirror including a first portion directly attached to the platform such that the first portion cannot move relative to the platform and a second portion that is not attached to the platform such that the second portion can move relative to the platform, the micromirror including a material that is configured to enable the second portion of the micromirror to move relative to the platform responsive to an input; and
at least one light source positioned to direct light toward the micromirror, whereby application of an electrical signal to at least one of the plurality of support elements moves the platform to aid in controlling a reflection of light received from the at least one light source.

27. The system of claim 26 , further comprising a control unit configured to control the application of the electrical si

Assignees

• Univ Boston
• Bishop David J
• Little Thomas
• Morrison Jessica
• Imboden Matthias

Inventors

• Bishop David J
• Little Thomas
• Morrison Jessica
• Imboden Matthias

Classifications

• G02B26/085

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

• G02B26/02

  for controlling the intensity of light {(G02B26/004 takes precedence)} · CPC title

• G02B26/06

  for controlling the phase of light (G02B26/08 takes precedence {, measuring optical phase difference G01J9/00}) · CPC title

• G02B6/3518 Primary

  the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device (MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833) · CPC title

• G02B6/3584

  constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching (MEMS per se B81B, B81C) · CPC title