Deformable mirror device with oscillating states for providing smaller controllable adjustment of light intensity

• US 7,956,319 B2
• Filed: 12/24/2007
• Issued: 06/07/2011
• Est. Priority Date: 11/01/2003
• Status: Expired due to Fees

• Current Assignee: Olympus Corporation, Silicon Quest Kabushiki-Kaisha
• Original Assignee: Olympus Corporation, Silicon Quest Kabushiki-Kaisha
• Inventors: Maeda, Yoshihiro, Ichikawa, Hirotoshi, Arai, Kazuma, Ishii, Fusao
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US12/004,641
• Publication Number:
  US 20080192212A1
• Time in Patent Office: 1,261 Days
• Field of Search: 250/216, 250234-236, 250/214.R, 250/231.1, 353/77, 353/79, 353/98, 353/37, 353/50, 353/64, 353/73, 359290-298, 359223-225
• US Class Current: 250/235
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2320/0266 Reduction of sub-frame artefacts
• CPC Class Codes: G09G 3/001 using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/2081 with combination of amplitude modulation and time modulation space and time error diffusion G09G3/2066
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833

Abstract

A mirror device including: a mirror arranged on a substrate, supported by a hinge, and arranged substantially parallel to the substrate; a plurality of address electrodes for deflecting the mirror to an ON state, an OFF state, or an oscillating state; and a drive circuit for applying a voltage to the plurality of address electrodes. The mirror device is controlled such that a voltage can be applied to a corresponding address electrode to deflect the mirror, and oscillation in the oscillating state can be started from a state of the deflected mirror.

Claims

1. A method for controlling a mirror device comprises a mirror supported by a deflectable hinge disposed on a substrate for reflecting an incident light to different deflection angles comprising:

applying a voltage to one electrode of a plurality of address electrodes to control the mirror supported by said deflectable hinge to deflect to an ON deflection angle, an OFF deflection angle opposite said ON deflection angle, an intermediate ON deflection angle next to and smaller than said ON deflection angle and an intermediate OFF deflection angle next to and smaller than said OFF deflection angle; and

controlling the mirror to start oscillating said mirror between said intermediate ON deflection angle and said intermediate OFF deflection angle when the mirror is operated at the ON deflection angle or the OFF deflection angle.

2. The method according to claim 1, wherein:

said step of controlling the mirror to oscillate between the intermediate ON deflection angle and the intermediate OFF deflection angle further comprising a step of controlling the mirror to repeatedly oscillate between said intermediate ON and said intermediate OFF deflection angles on two opposite sides of a zero deflection angle when the mirror is substantially parallel to the substrate.

3. The method according to claim 1, wherein:

said step of controlling the mirror further comprising a step of applying a voltage to a first electrode of said address electrodes to deflect the mirror to either the ON deflection angle or the OFF deflection angle and applying the voltage to a second electrode of said address electrodes to deflect the mirror to said intermediate ON or said intermediate OFF deflection angle.

4. The method according to claim 3, wherein:

said step of applying the voltage to said second electrode of the address electrodes further comprising a step of controlling the mirror to deflect to either the ON deflection angle or the OFF deflection angle.

5. The method according to claim 3, wherein:

said step of applying a voltage to the first and second electrodes of the address electrodes further comprising a step of applying a voltage to the second electrode for applying a smaller electrostatic force for deflecting the mirror than the electrostatic force for deflecting the mirror applied from the first electrode of the address electrodes.

6. The method according to claim 3, wherein:

said step of applying a voltage to the first and second electrodes of the address electrodes further comprising a step of applying a voltage to the second electrode for applying a greater electrostatic force for deflecting the mirror than the electrostatic force for deflecting the mirror applied from the first electrode of the address electrodes.

7. The method according to claim 3, wherein:

said step of applying a voltage to the first and second electrodes of the address electrodes further comprising a step of applying the voltage to the second electrode for applying a second electrostatic force to increase a deflecting speed of the mirror.

8. The method according to claim 3, wherein:

said step of applying a voltage to the first and second electrodes of the address electrodes further comprising a step of applying the voltage to the second electrode for applying a second electrostatic force to decrease a deflecting speed of the mirror.

9. The method according to claim 3, wherein:

said step of applying a voltage to the first and second electrodes of the address electrodes further comprising a step of applying the voltage to the second electrode for applying a second electrostatic force to stop the mirror at a predefined deflection angle.

10. A projection system, comprising:

a light source for projection an illumination light;

a mirror device having a plurality of mirror elements each having a mirror for modulating the illumination light by controlling the mirror to operate in one of an ON state with the mirror deflects to an ON deflection angle, an OFF state with the mirror deflects to an ON deflection angle opposite said ON deflection angle, and an oscillating state with the mirror oscillates between an intermediate ON deflection angle and an intermediate OFF deflection angle wherein said intermediate ON deflection angle is next to and smaller than said ON deflection angle and said intermediate OFF deflection angle is next to and smaller than said OFF deflection angle; and

a control circuit for driving and controlling the mirror device to change from either the ON or OFF state to start operating the mirror in said oscillating state for reflecting a partial light intensity to a projection light path for displaying an image wherein the partial light intensity is less than a light intensity reflected in the ON state and larger greater than the light intensity reflected in the OFF state.

11. The system according to claim 10, wherein:

the control circuit controls the mirror device with said oscillating state to modulate and reflect the light to the projection light path to have more different light intensity levels for displaying the image with more grayscales than another system with the mirror controlled and operated with only the ON and OFF states.

12. The system according to claim 10, wherein:

each of said mirror elements further comprises an address electrode electrically connected to the control circuit wherein said control circuit applies a voltage to said address electrode to control the deflection angle of the mirror in each of the mirror elements.

13. The system according to claim 10, wherein:

the control circuit further controls the mirror in each of the mirror elements to operate the mirror in an oscillating state for continuously oscillating the mirror between the intermediate ON deflection angle and an intermediate OFF deflection angle.

14. A mirror device supported on a substrate comprises wherein each of said mirror elements further comprising:

a plurality of mirror-elements each having a mirror and a hinge disposed on the substrate to support the mirror;

each of said mirror elements includes a plurality of address electrodes; and

a control circuit for applying a voltage to the plurality of address electrodes to control the mirror to deflect the mirror for operating the mirror in an oscillating state with the mirror continuously oscillates between an intermediate ON deflection angle and an intermediate OFF deflection angle wherein said intermediate ON deflection angle is next to and smaller than an ON deflection angle and said intermediate OFF deflection angle is next to and smaller than an OFF deflection angle.

15. The device according to claim 14, wherein:

the control circuit applies a voltage to the address electrodes in each of the mirror elements to generate a first and a second electrostatic forces to deflect the mirror in a same direction.

16. The device according to claim 14, wherein:

the control circuit applies a voltage to the address electrodes in each of the mirror elements to generate a first and a second electrostatic forces force to deflect the mirror in two different directions.

17. The device according to claim 14, wherein:

the control circuit applies a voltage to the address electrodes in each of the mirror elements to control the mirror to stay at said ON deflection angle as an ON state, and the control circuit further controls the mirror to stay at said intermediate ON deflection angle as an intermediate state.

18. The device according to claim 14, wherein:

the control circuit applies a voltage to the address electrodes in each of the mirror elements to control the mirror to stay at said OFF deflection angle as an OFF state, and the control circuit further controls the mirror to stay at said intermediate ON deflection angle as an intermediate state.

19. The device according to claim 14, wherein:

the control circuit controls the mirror to continuously oscillate between the intermediate ON deflection angle and the intermediate OFF deflection angle wherein said intermediate ON deflection angle is unsymmetrical to said intermediate OFF deflection angle relative to a zero deflection angle when the mirror is substantially parallel to the substrate.

20. The device according to claim 14, wherein:

the control circuit further controls the mirror to stay at said intermediate ON deflection angle as an intermediate ON state.

21. The device according to claim 14, wherein:

the control circuit controls the mirror to continuously oscillate between the intermediate ON deflection angle and the intermediate OFF deflection angle wherein said intermediate ON deflection angle is symmetrical to said intermediate OFF deflection angle relative to a zero deflection angle when the mirror is substantially parallel to the substrate.

22. The device according to claim 14, wherein:

the control circuit controls the voltage of zero volt applied to the plurality of address electrodes for controlling the mirror to have a to free oscillation.

23. The device according to claim 14, wherein:

the mirror is electrically connected to a ground voltage.