Micromirror device and projector employing the same

• US 6,781,731 B2
• Filed: 09/26/2001
• Issued: 08/24/2004
• Est. Priority Date: 03/02/2001
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Soon-cheol
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): HANIG, RICHARD E
• Application Number:
  US09/962,311
• Publication Number:
  US 20020122159A1
• Time in Patent Office: 1,063 Days
• Field of Search: 359/290, 359/291, 359/321, 359/223, 359/224, 359/636, 359/639, 359/634, 359/635, 353/31, 353/98, 353/99
• US Class Current: 359/220.1
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 27/18 for optical projection, e.g. combination of mirror and condenser and objective photographic, cine and overhead projectors G03B21/00; photographic projection printing G03B27/32; photolithographic projectors G03F7/20; projection television H04N5/74; colour projection television H04N9/31
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

A projector includes a light source emitting a light beam and a light beam splitting unit splitting the light beam from the light source according to a wavelength region of the light beam and transmitting and/or reflecting the light beam split at different angles. A micromirror device forms an image by independently pivoting a micromirror in a predetermined direction and angle and controlling the micromirror to selectively reflect the light beam, the micromirror tilting with respect to rotation axes. A projection lens unit magnifies and transmits an incident light beam from the micromirror devices to proceed to a screen to form the image.

Claims

1. A micromirror device for driving a micromirror, the micromirror device comprising:

a substrate;

electrodes on the substrate;

first posts; and

a support frame supported by the first posts and tilting with respect to rotation axes using portions supported by each of the first posts as hinge points.

2. The micromirror device as claimed in claim 1, wherein the electrodes are symmetrically arranged in pairs on opposite sides of the substrate, each pair of electrodes facing each other.

3. The micromirror device as claimed in claim 2, wherein each of the electrodes comprises a set of two electrodes.

4. The micromirror device as claimed in claim 2, wherein the micromirror tilts with respect to two rotation axes.

5. The micromirror device as claimed in claim 4, wherein the rotation axes are perpendicular to each other.

6. The micromirror device as claimed in claim 5, wherein the support frame comprises:

a second post protruding from the support frame supporting the micromirror;

a center portion supporting the second post; and

two pairs of springs connecting the first posts with the center portion.

7. The micromirror device as claimed in claim 6, wherein the two pairs of springs are arranged to be symmetrical with respect to each other and have zigzag shapes to be twisted and elastically deformed when the micromirror tilts.

8. The micromirror device as claimed in claim 7, wherein:

when an electrostatic force tilts the micromirror, each pair of springs facing each other along a rotation axis is elastically deformed and twisted, and

when the electrostatic force is removed, the micromirror is returned to an original state by a restoration force from each pair of springs.

9. The micromirror device as claimed in claim 1, wherein the support frame comprises:

a second post protruding from the support frame supporting the micromirror;

a center portion supporting the second post; and

two pairs of springs connecting the first posts with the center portion.

10. The micromirror device as claimed in claim 7, wherein:

the micromirror tilts with respect to an X—

X axis by applying a voltage to one of the pairs of electrodes facing each other and with respect to a Y—

Y axis by applying the voltage to another of the pairs of electrodes facing each other.

11. The micromirror device as claimed in claim 10, wherein:

each pair of springs facing each other along the X—

X or Y—

Y rotation axis is elastically deformed and twisted when an electrostatic force along a corresponding one of the rotation axes tilts the micromirror.

12. The micromirror device as claimed in claim 1, wherein:

an angle and direction of tilt of the micromirror are determined by an amount of voltage applied to an electrode.

13. The micromirror as claimed in claim 12, wherein the substrate comprises a built-in SRAM and a tilting angle and direction of the micromirror is adjusted according to an image stored in the SRAM.

14. The micromirror device as claimed in claim 1, wherein the first posts comprise at least three posts.

15. The micromirror device as claimed in claim 1, wherein the micromirror tilts with respect to two rotation axes.

16. The micromirror as claimed in claim 1, wherein the substrate comprises an SRAM storing information to form an image.

17. A micromirror device for driving a micromirror, the micromirror device comprising:

a substrate;

electrodes on the substrate;

first posts; and

a support frame supported by the first posts and tilting with respect to two rotation axes using portions supported by each of the first posts as hinge points, wherein the micromirror device excludes a color wheel.

18. A projector, comprising:

a light source emitting a light beam;

a light beam splitting unit splitting the light beam from the light source according to a wavelength region of the light beam and transmitting and/or reflecting the light beam split at different angles;

micromirrors;

micromirror devices forming an image by independently pivoting each of the micromirrors in a predetermined direction and angle and controlling the micromirrors to selectively reflect the split light beam, each of the micromirrors tilting with respect to rotation axes;

a screen; and

a projection lens unit magnifying and transmitting an incident light beam from the micromirror devices to proceed to the screen to form the image.

19. The projector as claimed in claim 18, wherein each of the micromirror devices comprises:

a substrate;

electrodes on the substrate;

first posts;

a support frame supported by the first posts and tilting with respect to the rotation axes using portions supported by each of the first posts as hinge points;

a second post protruding from the support frame; and

one of the micromirrors supported by the second post and tilting by interaction with the electrodes.

20. The projector as claimed in claim 19, wherein the electrodes are symmetrically arranged in pairs on opposite sides of the substrate, each pair of electrodes facing each other.

21. The projector as claimed in claim 19, wherein the micromirror tilts with respect to two rotation axes.

22. The projector as claimed in claim 21, wherein the rotation axes are perpendicular to each other.

23. The projector as claimed in claim 22, wherein the support frame comprises:

a center portion supporting the second post; and

two pairs of springs connecting the first posts with the center portion.

24. The projector as claimed in claim 23, wherein the two pairs of springs are arranged to be symmetrical with respect to each other and have zigzag shapes to be twisted and elastically deformed when the micromirror tilts.

25. The projector device as claimed in claim 21, wherein the support frame comprises:

a center portion supporting the second post; and

two pairs of springs connecting the first posts with the center portion.

26. The projector device as claimed in claim 19, wherein the light beam splitting unit splits the light beam from the light source into red, green, and blue light beams.

27. The projector device as claimed in claim 26, wherein:

the micromirror device guides the red, green, and blue light beams incident on a surface of the micromirror on a path and focuses and/or diverges the red, green, and blue light beams towards the projection lens unit, and

the projection lens unit magnifies and projects the red, green, and blue light beams from the micromirror device towards the screen.

28. The projector device as claimed in claim 27, wherein:

the micromirror device changes the proceeding path of the light beam by tilting the micromirror at a predetermined angle and excludes a color wheel.

29. The projector device as claimed in claim 26, wherein:

the red light beam comprises a red wavelength region, the blue light beam comprises a blue wavelength region, and the green light beam comprises a green wavelength region.

30. The projector device as claimed in claim 29, wherein the light beam splitting unit comprises:

a first total reflection mirror;

a second total reflection mirror;

a first dichromatic mirror reflecting the red light beam towards the first total reflection mirror and transmitting the green and blue light beams; and

a second dichromatic mirror receiving the green and blue light beams from the first dichromatic mirror, reflecting the green light beam towards the second total reflection mirror and transmitting the blue light beam.

31. The projector device as claimed in claim 30, wherein the micromirror device receives the red light beam, the green light beam, and the blue light beam at different incident angles from the first total reflection mirror, the second total reflection mirror, and the second dichromatic mirror, respectively, and selectively outputs each of the red, green, and blue light beams to the projection lens unit according to the incident angles of each of the red, green, and blue light beams and a tilt angle of the micromirror corresponding to each incident angle to realize color.

32. The projector device as claimed in claim 19, wherein the micromirror comprises two rotation axes realizing color left and right and up and down.

33. The projector device as claimed in claim 19, wherein the light source comprises:

a lamp generating the light beam; and

a reflection mirror reflecting the light beam, wherein the reflection mirror comprises an oval shape having one focal point at a position of the lamp and another focal point at a point where the light beam is focused in the light beam splitting unit.

34. The projector device as claimed in claim 30, further comprising

a parabolic mirror having a focal point at the position of the lamp, making the light beam emitted from the lamp and reflected by the reflection mirror to be a parallel beam.

35. A micromirror device for driving a micromirror, the micromirror device comprising:

a substrate comprising a built-in SRAM;

electrodes on the substrate to tilt the micromirror;

at least three posts on the substrate; and

a support frame supported by the posts, wherein the micromirror is tilted in four directions by interaction with the electrodes using portions supported by each of the first posts as hinge points.

36. The micromirror device as claimed in claim 35, wherein the direction of a tilt of the micromirror is independently adjusted by the SRAM.

37. The micromirror device as claimed in claim 36, wherein each of the micromirrors tilts with respect to two rotation axes.

38. The micromirror device as claimed in claim 37, wherein the rotation axes are perpendicular to each other.

39. A micromirror device, comprising:

a micromirror receiving a red light beam, a green light beam, and a blue light beam at different angles, and

a projection lens unit selectively receiving and displaying each of the red, green, and blue light beams according to incident angles of each of the red, green, and blue light beams and a tilt angle of the micromirror corresponding to each of the incident angles to realize color.

40. A micromirror device for driving a micromirror, the micromirror device comprising:

a substrate;

electrodes on the substrate; and

a support frame supported by tilting with respect to rotation axes, wherein the micromirror tilts in four directions by applying a voltage to any one of the electrodes; and

a projection lens unit selectively displaying red, green, and blue colors according to a direction of tilt of the micromirror.

41. The micromirror device claimed in claim 40, wherein the micromirror device excludes a color wheel.

42. The micromirror device as claimed in claim 40, wherein the support frame comprises:

a second post protruding from the support frame supporting the micromirror;

a center portion supporting the second post; and

two pairs of springs connecting the first posts with the center portion.

43. The micromirror device as claimed in claim 40, wherein:

when an electrostatic force tilts the micromirror, each pair of springs facing each other along a rotation axis is elastically deformed and twisted; and

when the electrostatic force is removed, the micromirror is returned to an original state by a restoration force from each pair of springs.

44. The micromirror device as claimed in claim 40, wherein:

the micromirror tilts with respect to an X—

X axis by a pair of electrodes facing each other and with respect to a Y—

Y axis by another pair of electrodes facing each other.

45. The micromirror device as claimed in claim 44, wherein:

each pair of springs facing each other along the X—

X or Y—

Y rotation axis is elastically deformed and twisted when an electrostatic force along a corresponding one of the rotation axes tilts the micromirror.