Micro-mirror device with light angle amplification

• US 6,972,882 B2
• Filed: 03/12/2003
• Issued: 12/06/2005
• Est. Priority Date: 04/30/2002
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Ring, James W., Dahlgren, Brett E., McMahon, Terry E.
• Primary Examiner(s): Pritchett, Joshua L.
• Application Number:
  US10/387,310
• Publication Number:
  US 20030202266A1
• Time in Patent Office: 1,000 Days
• Field of Search: 359223-226, 359/390, 359/391, 359/871
• US Class Current: 359/223.1
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 2203/0109 Bridges
• CPC Class Codes: B81B 7/04 Networks or arrays of similar microstructural devices
• CPC Class Codes: G02B 26/004 based on a displacement or a deformation of a fluid
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

A micro-mirror device includes a substrate and a plate spaced from and oriented substantially parallel to the substrate such that the plate and the substrate define a cavity therebetween. A reflective element is interposed between the substrate and the plate, and a liquid having an index of refraction greater than one is disposed in the cavity between at least the reflective element and the plate. As such, the reflective element is adapted to move between a first position and at least one second position.

Claims

1. A micro-mirror device, comprising:

a substrate having a surface;

a plate spaced from the substrate and oriented substantially parallel to the substrate, the plate having a surface oriented substantially parallel to the surface of the substrate, and the plate and the substrate defining a cavity therebetween;

a reflective element interposed between the substrate and the plate; and

a liquid having an index of refraction greater tan one disposed in the cavity between at least the reflective element and the plate,

wherein the reflective element is adapted to move between a first position and at least one second position, and reflect light through the surface of the plate.

2. The device of claim 1, wherein the at least one second position is oriented at an angle to the first position.

3. The device of claim 1, wherein the reflective element is adapted to reflect light through the liquid, and the liquid is adapted to increase an exit angle of the light from the cavity for a given tilt angle of the reflective element.

4. The device of claim 1, wherein the reflective element is adapted to reflect light through the liquid, and the liquid is adapted to produce an exit angle of the light from the cavity corresponding to a tilt angle of the reflective element greater than an actual tilt angle of the reflective element.

5. The device of claim 1, wherein the index of refraction of the liquid is in a range of approximately 1.3 to approximately 1.7.

6. The device of claim 1, wherein the liquid includes a dielectric liquid.

7. The device of claim 1, wherein the plate and the liquid are substantially transparent.

8. The device of claim 1, wherein the plate has an index of refraction substantially equal to the index of refraction of the liquid.

9. The device of claim 1, wherein the reflective element is adapted to reflect light through the liquid and the plate, and wherein a thickness of the plate is substantially thin such that refraction at the plate is substantially negligible.

10. The device of claim 1, wherein the reflective element is submerged in the liquid.

11. The device of claim 1, further comprising:

at least one electrode formed on the substrate,

wherein the reflective element is adapted to move in response to application of an electrical signal to the at least one electrode.

12. The device of claim 1, further comprising:

at least one post extending from the substrate and supporting the reflective element.

13. The device of claim 12, further comprising:

a conductive via extending through the at least one post and electrically coupled to the reflective element,

wherein the reflective element is adapted to move in response to application of an electrical signal to the reflective element through the conductive via.

14. A display device including the micro-mirror device of claim 1.

15. An optical switch including the micro-mirror device of claim 1.

16. A method of forming a micro-mirror device, the method comprising:

providing a substrate having a surface;

orienting a surface of a plate substantially parallel to the surface of the substrate and spacing the plate from the substrate, including defining a cavity between the plate and the substrate;

interposing a reflective element between the substrate and the plate; and

disposing a liquid having an index of refraction greater than one in the cavity between at least the reflective element and the plate,

wherein the reflective element is adapted to move between a first position and at least one second position, and reflect light through the surface of the plate.

17. The method of claim 16, wherein the at least one second position is oriented at an angle to the first position.

18. The method of claim 16, wherein the reflective element is adapted to reflect light through the liquid and the liquid is adapted to increase an exit angle of the light from the cavity for a given tilt angle of the reflective element.

19. The method of claim 16, wherein the reflective element is adapted to reflect light through the liquid and the liquid is adapted to produce an exit angle of the light from the cavity corresponding to a tilt angle of the reflective element greater than an actual tilt angle of the reflective element.

20. The method of claim 16, wherein the index of refraction of the liquid is in a range of approximately 1.3 to approximately 1.7.

21. The method of claim 16, wherein the liquid includes a dielectric liquid.

22. The method of claim 16, wherein the plate and the liquid are substantial transparent.

23. The method of claim 16, wherein the plate has an index of refraction substantially equal to the index of refraction of the liquid.

24. The method of claim 16, wherein the reflective element is adapted to reflect light through the liquid and the plate, and wherein a thickness of the plate is substantially thin such that refraction at the plate is substantially negligible.

25. The method of claim 16, wherein interposing the reflective element between the substrate and the plate includes submerging the reflective element in the liquid.

26. The method of claim 16, further comprising:

forming at least one electrode on the substrate,

wherein the reflective element is adapted to move in response to application of an electrical signal to the at least one electrode.

27. The method of claim 16, further comprising:

extending at least one post from the substrate,

wherein interposing the reflective element between the substrate and the plate includes supporting the reflective element from the at least one post.

28. The method of claim 27, further comprising:

extending a conductive via through the at least one post and electrically coupling the conductive via with the reflective element,

wherein the reflective element is adapted to move in response to application of an electrical signal to the reflective element through the conductive via.

29. A micro-mirror device, comprising:

a substrate having a surface;

a plate spaced from the substrate and oriented substantially parallel to the substrate, wherein the plate has a surface oriented substantially parallel to the surface of the substrate, and the plate and the substrate define a cavity therebetween;

a reflective element interposed between the substrate and the plate in the cavity, wherein the reflective element is adapted to reflect light from the cavity and through the surface of the plate; and

means for amplifying an exit angle of light from the cavity for a given tilt angle of the reflective element.

30. The device of claim 29, further comprising:

means for moving the reflective element between a first position and at least one second position.

31. The device of claim 30, wherein means for moving the reflective element includes means for moving the reflective element through an angle between the first position and the at least one second position.

32. The device of claim 29, wherein means for amplifying the exit angle of light from the cavity includes means for exiting the light from the cavity with the exit angle corresponding to an apparent tilt angle of the reflective element greater than an actual tilt angle of the reflective element.

33. The device of claim 29, wherein means for amplifying the exit angle of light from the cavity includes a liquid having an index of refraction greater than one disposed in the cavity between the reflective element and the plate.

34. The device of claim 33, wherein the index of refraction of the liquid is in a range of approximately 1.3 to approximately 1.7.

35. The device of claim 33, wherein the liquid includes a dielectric liquid.

36. The device of claim 33, wherein the plate has an index of refraction substantially equal to the index of refraction of the liquid.

37. The device of claim 33, wherein the reflective element is adapted to direct the light through the liquid and through an interface with the liquid, wherein the light is adapted to refract at the interface with the liquid.

38. The device of claim 33, wherein the reflective element is adapted to direct the light through the liquid and the plate, wherein the plate is of a thickness such that refraction at the plate is substantially negligible.

39. A method of controlling light with a micro-mirror device including a reflective element interposed between a substrate and a transparent plate, the method comprising:

receiving light at the reflective element through a surface of the transparent plate oriented substantially parallel to a surface of the substrate; and

reflecting the light with the reflective element, including directing the light through a liquid having an index of refraction greater than one, through an interface with the liquid, and back through the transparent plate,

wherein directing the light through the interface with the liquid includes refracting the light at the interface with the liquid.

40. The method of claim 39, wherein refracting the light at the interface with the liquid includes amplifying an exit angle of the light from the liquid for a given tilt angle of the reflective element.

41. The method of claim 39, wherein refracting the light at the interface with the liquid includes exiting the light from the liquid with an exit angle corresponding to an apparent tilt angle of the reflective element greater than an actual tilt angle of the reflective element.

42. The method of claim 39, wherein the index of refraction of the liquid is in a range of approximately 1.3 to approximately 1.7.

43. The method of claim 39, wherein the liquid includes a dielectric liquid.

44. The method of claim 39, further comprising:

moving the reflective element between a first position and at least one second position oriented at an angle to the first position.

45. The method of claim 44, when moving the reflective element between the first position and the at least one second position includes directing the light in a first direction when the reflective element is in the first position and directing the light in a second direction when the reflective element is in the at least one second position.

46. A method of using a liquid having an index of refraction greater than one in a micro-mirror device including a reflective element interposed between a substrate and a transparent plate, the method comprising:

receiving light at the reflective element through a surface of the transparent plate oriented substantially parallel to a surface of the substrate;

reflecting the light with the reflective element, including directing the light through the liquid, through an interface with the liquid, and back through the transparent plate; and

refracting the light at the interface with the liquid, including increasing an exit angle of the light from the micro-mirror device for a given tilt angle of the reflective element.

47. A method of using a liquid having an index of refraction greater than one in a micro-mirror device including a reflective element interposed between a substrate and a transparent plate, the method comprising:

receiving light at the reflective element through a surface of the transparent plate oriented substantially parallel to a surface of the substrate;

reflecting the light with the reflective element, including directing the light through the liquid, through an interface with the liquid, and back through the transparent plate; and

refracting the light at the interface with the liquid, including exiting the light from the micro-mirror device with an exit angle corresponding to an apparent tilt angle of the reflective element greater than an actual tilt angle of the reflective element.

48. A method of using a liquid having an index of refraction greater than one in a micro-mirror device including a reflective element interposed between a substrate and a transparent plate, the method comprising:

receiving light at the reflective element through a surface of the transparent plate oriented substantially parallel to a surface of the substrate;

reflecting the light with the reflective element, including directing the light through the liquid, through an interface with the liquid, and back through the transparent plate; and

refracting the light at the interface with the liquid, including reducing a tilt angle of the reflective element for a desired exit angle of the light from the micro-mirror device.

49. A method of using a liquid having an index of refraction greater than one in a micro-mirror device including a reflective element, the method comprising:

reflecting light with the reflective element, including directing the light through the liquid and through an interface with the liquid;

moving the reflective element through a tilt angle between a first position and at least one second position; and

refracting the light at the interface with the liquid, including reducing the tilt angle of the reflective element for a desired exit angle of the light from the micro-mirror device,

wherein reducing the tilt angle of the reflective element for the desired exit angle of the light includes increasing a response time of moving the reflective element between the first position and the at least one second position.

50. A method of using a liquid having an index of refraction greater than one in a micro-mirror device including a reflective element, the method comprising:

reflecting light with the reflective element, including directing the light through the liquid and through an interface with the liquid;

moving the reflective element through a tilt angle between a first position and at least one second position; and

reflecting the light at the interface with the liquid, including reducing the tilt angle of the reflective element for a desired exit angle of the light from the micro-mirror device,

wherein reducing the tilt angle of the reflective element for the desired exit angle of the light includes reducing fatigue of the micro-mirror device while moving the reflective element between the first position and the at least one second position.