Rolling shutter optical switch device with latch electrode and slits in shutter

• US 6,907,153 B2
• Filed: 03/05/2001
• Issued: 06/14/2005
• Est. Priority Date: 03/03/2000
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Rabe, Steven, Bozler, Carl O.
• Primary Examiner(s): Patidar, Jay
• Application Number:
  US09/799,923
• Publication Number:
  US 20020018613A1
• Time in Patent Office: 1,562 Days
• Field of Search: 359/223, 359/224, 359/227, 359/230, 359/838, 359846-848, 359/290, 359/291, 385/16, 385/17, 385/18, 385/19
• US Class Current: 385/16
• CPC Class Codes: B81B 2201/045 Optical switches
• CPC Class Codes: B81B 3/0008 Structures for avoiding electrostatic attraction, e.g. avoiding charge accumulation
• CPC Class Codes: B81B 3/0072 For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G02B 6/3518 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 Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3564 Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/358 Latching of the moving element, i.e. maintaining or holding the moving element in place once operation has been performed; includes a mechanically bistable system
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C

Abstract

An optical switch device includes a rolling shutter or membrane attached at one of its edges to a substrate near an optical port in the substrate. The rolling shutter can assume one of two states. In a first closed state, the membrane is uncoiled onto the substrate over the port such that light directed at the port impinges on the shutter. In a second open state, the membrane is rolled up away from the port such that light directed at the port impinges on the port. In one embodiment, a mirror is formed on the membrane such that when the membrane is in the closed state over the substrate, light directed at the port is reflected by the mirror. In one configuration, the optical port includes a hole or aperture such light passed through the port without interference. The device can include a latch electrode the far end of the membrane such that when it is rolled out, it can be held in position by a latching voltage applied across the latch electrode and the substrate. Slits can be formed in the membrane to keep the mirror flat by relieving strain in the membrane and to allow gases in proximity to the device to pass through the membrane as it is activated. The shutter can include dimples to minimize the area of contact between the membrane and the substrate to reduce the probability of the two sticking together. The attachment edge of the membrane can be made shorter than its width to reduce distortions in the membrane to keep the mirror flat. A raised annular rim can be provided around the port such that when the shutter is held down over the port it is pulled taut and flat over the rim. This feature is also used to maintain flatness in the mirror. The switch device can be used as part of an array of optical switches.

Claims

1. An optical switch device comprising:

a substrate;

a flexible membrane attached at least one end to a surface of the substrate in proximity to an optical port portion of the substrate, the flexible membrane being configured such that, in a first state, the flexible membrane is disposed over the optical port portion of the substrate such that light directed toward the optical port portion of the substrate impinges on the flexible membrane, and, in a second state, the flexible membrane is disposed to expose the optical port portion of the substrate such that light directed toward the optical port portion of the substrate impinges on the optical port portion of the substrate; and

a latch electrode on the substrate at a second end of the flexible membrane used to reduce sticking between said flexible membrane and said substrate, such that, when the flexible membrane is in the first state, upon application of a latching voltage between the latch electrode and the substrate, the flexible membrane is held in the first state.

2. The optical switch device of claim 1, wherein the flexible membrane is formed such that in the second state, the flexible membrane is coiled away from the optical port portion of the substrate, and, in the first state, the flexible membrane is uncoiled over the optical, port portion of the substrate.

3. The optical switch device of claim 2, wherein the flexible membrane is normally in a coiled condition, and, upon application of an operating voltage across the substrate and the flexible membrane, the flexible membrane uncoils over the optical port portion of the substrate.

4. The optical switch device of claim 1, further comprising a plurality of slits formed in the flexible membrane such that distortions in the flexible membrane are reduced.

5. The optical switch device of claim 1, further comprising a plurality of slits formed in the flexible membrane such that a gas in proximity to the optical switch device passes through the slits as the flexible membrane transitions between the first state and the second state.

6. An optical switch device comprising:

a substrate;

a flexible membrane attached at at least one end to a surface of the substrate in proximity to an optical port portion of the substrate, the flexible membrane being configured such that, in a first state, the flexible membrane is disposed over the optical port portion of the substrate such that light directed toward the optical port portion of the substrate impinges on the flexible membrane, and, in a second state, the flexible membrane is disposed to expose the optical port portion of the substrate such that light directed toward the optical port portion of the substrate impinges on the optical port portion of the substrate; and

a plurality of slits formed in the flexible membrane such that distortions in the flexible membrane are reduced.

7. The optical switch device of claim 6, wherein the flexible membrane is formed such that in the second state, the flexible membrane is coiled away from the optical port portion of the substrate, and, in the first state, the flexible membrane is uncoiled over the optical port portion of the substrate.

8. The optical switch device of claim 7, wherein the flexible membrane is normally in a coiled condition, and, upon application of an operating voltage across the substrate and the flexible membrane, the flexible membrane uncoils over the optical port portion of the substrate.

9. The optical switch device of claim 6, further comprising a second plurality of slits formed in the flexible membrane such that a gas in proximity to the optical switch device passes through the second plurality of slits as the flexible membrane transitions between the first state and the second state.

10. An optical switch device comprising:

a substrate;

a flexible membrane attached at at least one end to a surface of the substrate in proximity to an optical port portion of the substrate, the flexible membrane being configured such that, in a first state, the flexible membrane is disposed over the optical port portion of the substrate such that light directed toward the optical port portion of the substrate impinges on the flexible membrane, and, in a second state, the flexible membrane is disposed to expose the optical port portion of the substrate such that light directed toward the optical port portion of the substrate impinges on the optical port portion of the substrate; and

a plurality of slits formed in the flexible membrane such that a gas in proximity to the optical switch device passes through the slits as the flexible membrane transitions between the first state and the second state.

11. The optical switch device of claim 10, wherein the flexible membrane is formed such that in the second state, the flexible membrane is coiled away from the optical port portion of the substrate, and, in the first state, the flexible membrane is uncoiled over the optical port portion of the substrate.

12. The optical switch device of claim 11, wherein the flexible membrane is normally in a coiled condition, and, upon application of an operating voltage across the substrate and the flexible membrane, the flexible membrane uncoils over the optical port portion of the substrate.

13. An optical switching method comprising:

providing a substrate;

attaching a flexible membrane at least one end to a surface of the substrate in proximity to an optical port portion of the substrate, the flexible membrane being configured such that, in a first state, the flexible membrane is disposed over the optical port portion of the substrate such that light directed toward the optical port portion of the substrate impinges on the flexible membrane, and, in a second state, the flexible membrane is disposed to expose the optical port portion of the substrate such that light directed toward the optical port portion of the substrate impinges on the optical port portion of the substrate; and

providing a latch electrode on the substrate at a second end of the flexible membrane used to reduce sticking between said flexible membrane and said substrate, such that, when the flexible membrane is in the first state, upon application of a latching voltage between the latch electrode and the substrate, the flexible membrane is held in the first state.

14. The optical switching method of claim 13, further comprising forming the flexible membrane such that in the second state, the flexible membrane is coiled away from the optical port portion of the substrate, and, in the first state, the flexible membrane is uncoiled over the optical port portion of the substrate.

15. The optical switching method of claim 14, further comprising forming the flexible membrane such that the flexible membrane is normally in a coiled condition, and, upon application of an operating voltage across the substrate and the flexible membrane, the flexible membrane uncoils over the optical port portion of the substrate.

16. The optical switching method of claim 13, further comprising forming a plurality of slits in the flexible membrane such that distortions in the flexible membrane are reduced.

17. The optical switching method of claim 13, further comprising forming a plurality of slits in the flexible membrane such that a gas in proximity to the optical switch device passes through the slits as the flexible membrane transitions between the first state and the second state.

18. An optical switching method comprising:

forming a substrate;

attaching a flexible membrane at at least one end to a surface of the substrate in proximity to an optical port portion of the substrate, the flexible membrane being configured such that, in a first state, the flexible membrane is disposed over the optical port portion of the substrate such that light directed toward the optical port portion of the substrate impinges on the flexible membrane, and, in a second state, the flexible membrane is disposed to expose the optical port portion of the substrate such that light directed toward the optical port portion of the substrate impinges on the optical port portion of the substrate; and

forming a plurality of slits in the flexible membrane such that distortions in the flexible membrane are reduced.

19. The optical switching method of claim 18, further comprising forming the flexible membrane such that in the second state, the flexible membrane is coiled away from the optical port portion of the substrate, and, in the first state, the flexible membrane is uncoiled over the optical port portion of the substrate.

20. The optical switching method of claim 18 further comprising forming the flexible membrane such that the flexible membrane is normally in a coiled condition, and, upon application of an operating voltage across the substrate and the flexible membrane, the flexible membrane uncoils over the optical port portion of the substrate.

21. The optical switching method of claim 18, further comprising forming a second plurality of slits in the flexible membrane such that a gas in proximity to the optical switch device passes through the second plurality of slits as the flexible membrane transitions between the first state and the second state.

22. An optical switching method comprising:

forming a substrate;

attaching a flexible membrane at at least one end to a surface of the substrate in proximity to an optical port portion of the substrate, the flexible membrane being configured such that, in a first state, the flexible membrane is disposed over the optical port portion of the substrate such that light directed toward the optical port portion of the substrate impinges on the flexible membrane, and, in a second state, the flexible membrane is disposed to expose the optical port portion of the substrate such that light directed toward the optical port portion of the substrate impinges on the optical port portion of the substrate; and

forming a plurality of slits in the flexible membrane such that a gas in proximity to the optical switch device passes through the slits as the flexible membrane transitions between the first state and the second state.

23. The optical switching method of claim 22, further comprising forming the flexible membrane such that in the second state, the flexible membrane is coiled away from the optical port portion of the substrate, and, in the first state, the flexible membrane is uncoiled over the optical port portion of the substrate.

24. The optical switching method of claim 23, further comprising forming the flexible membrane such that the flexible membrane is normally in a coiled condition, and, upon application of an operating voltage across the substrate and the flexible membrane, the flexible membrane uncoils over the optical port portion of the substrate.