Projection display system with varying light source

• US 7,826,128 B2
• Filed: 09/04/2008
• Issued: 11/02/2010
• Est. Priority Date: 05/23/2005
• Status: Expired due to Fees

• Current Assignee: Olympus Corporation, Silicon Quest Kabushiki-Kaisha
• Original Assignee: Olympus Corporation, Silicon Quest Kabushiki-Kaisha
• Inventors: Nishino, Hirokazu, Shirai, Akira, Ishii, Fusao, Horikawa, Yoshiaki
• Primary Examiner(s): Thompson; Timothy J
• Application Number:
  US12/231,708
• Publication Number:
  US 20090231669A1
• Time in Patent Office: 789 Days
• Field of Search: 359/290, 359/291, 353/31, 353/33, 353/34, 353/84, 349/5
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833
• CPC Class Codes: H04N 9/312 Driving therefor driving of electronic spatial light modulators in displays other than projection devices G09G3/34, G09G3/36; control of liquid crystal elements G02F1/133; control of micromechanical modulators G02B26/08
• CPC Class Codes: H04N 9/3155 for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406

Abstract

The present invention provides a projection apparatus, comprising: a light source for emitting illumination light; at least one spatial light modulator with a plurality of movable mirrors corresponding to pixels to be displayed, for performing a modulation of the illumination light through operation of the movable mirrors; a light source control unit performing a modulation control of the light source; and a spatial light modulator control unit generating, from an input image signal, a control signal for driving the spatial light modulator, wherein: the light source control unit adjusts a pulse emission frequency of an emission pulse of the illumination light emitted from the light source while corresponding to an oscillation frequency of the movable mirrors.

Claims

1. A projection apparatus, comprising:

a light source for emitting illumination light;

at least one spatial light modulator with a plurality of movable mirrors corresponding to pixels to be displayed, for performing a modulation of the illumination light through operation of the movable mirrors;

a light source control unit performing a modulation control of the light source; and

a spatial light modulator control unit generating, from an input image signal, a control signal for driving the spatial light modulator, wherein the light source control unit controls a pulse emission frequency of an emission pulse of the illumination light emitted from the light source by adjusting the pulse emission frequency of the illumination light emitted from the light source to be ten times the oscillation frequency of the movable mirrors or higher.

3. The projection apparatus according to claim 1, wherein:

the light source control unit drives the light source by changing a pulse width of the emission pulse.

4. The projection apparatus according to claim 1, wherein:

the light source control unit drives the light source by changing a pulse intensity of the emission pulse.

5. The projection apparatus according to claim 1, wherein:

the light source is a laser diode or a light emitting diode (LED).

6. The projection apparatus according to claim 1, wherein:

the movable mirrors have an ON state of reflecting, to a projection optical system, the illumination light emitted from the light source, an OFF state of reflecting the illumination light to a position that is offset from the projection optical system, and an oscillation state in which the movable mirrors oscillate between the ON state and the OFF state.

8. The projection apparatus according to claim 1, comprising:

a plurality of the light sources respectively corresponding to at least red (R), green (G), and blue (B), wherein the light source control unit independently drives the light sources of R/G/B.

9. The projection apparatus according to claim 1, comprising:

the light sources of at least red (R) green (G), and blue (B), wherein;

the light source control unit performs a drive so that the spatial light modulator control unit adjusts an emission intensity of the illumination light for the light source of each of R/G/B synchronously with the control signal generated by the spatial light modulator control unit.

10. The projection apparatus according to claim 1, comprising:

a plurality of the spatial light modulators, wherein the spatial light modulator control unit generates the control signal for driving the plurality of spatial light modulators; and

the light source control unit receives the control signal for driving each of the spatial light modulators, and adjusts an emission intensity of the illumination light emitted from the light sources to the spatial light modulators.

21. The projection apparatus according to claim 1, wherein:

the light source control unit performs a control by stopping an emission of the light source during a period other than a period during a period when a control signal generated by the spatial light modulator control unit drives the spatial light modulator.

2. A projection apparatus comprising:

a light source for emitting illumination light;

at least one spatial light modulator with a plurality of movable mirrors corresponding to pixels to be displayed, for performing a modulation of the illumination light through operation of the movable mirrors; and

a light source control unit performing a modulation control of the light source; and

a spatial light modulator control unit generating, from an input image signal, a control signal for driving the spatial light modulator, wherein the light source control unit controls a pulse emission frequency of an emission pulse of the illumination light emitted from the light source by adjusting the pulse emission frequency of the illumination light emitted from the light source to be one-tenth the oscillation frequency of the movable mirrors or lower.

7. A projection apparatus comprising:

a light source for emitting illumination light;

at least one spatial light modulator with a plurality of movable mirrors corresponding to pixels to be displayed, for performing a modulation of the illumination light through operation of the movable mirrors;

a light source control unit performing a modulation control of the light source; and

a spatial light modulator control unit generating, from an input image signal, a control signal for driving the spatial light modulator, wherein the light source control unit controls a pulse emission frequency of an emission pulse of the illumination light emitted from the light source corresponding to an oscillation frequency of the movable mirrors; and

the light source control unit performs a control by stopping an emission of the light source during a period other than a period during a period when the control signal generated by the spatial light modulator control unit drives the spatial light modulator.

11. A projection apparatus, wherein:

a light source for emitting illumination light;

at least one spatial light modulator with a plurality of movable mirrors corresponding to pixels to be displayed, for performing a modulation of the illumination light through operation of the movable mirrors;

a light source control unit performing a modulation control of the light source; and

a spatial light modulator control unit generating, from an input image signal, a control signal for driving the spatial light modulator, wherein;

the light source control unit controls a pulse emission frequency of an emission pulse of the illumination light emitted from the light source so that the pulse emission frequency is ten times an oscillation frequency of the movable mirrors or higher.

12. The projection apparatus according to claim 11, wherein:

the light source control unit drives the light source so as to change a pulse width of the emission pulse.

13. The projection apparatus according to claim 11, wherein:

the light source control unit drives the light source so as to change a pulse intensity of the emission pulse.

14. The projection apparatus according to claim 11, wherein:

the light source is a laser diode or a light emitting diode (LED).

15. The projection apparatus according to claim 11, wherein:

the movable mirrors have an ON state of reflecting, to a projection optical system, the illumination light emitted from the light source, an OFF state of reflecting the illumination light to a position that is offset from the projection optical system, and an oscillation state in which the movable mirrors oscillate between the ON state and the OFF state.

16. A projection apparatus, comprising:

a light source for emitting illumination light;

at least one spatial light modulator with a plurality of movable mirrors corresponding to pixels to be displayed, for performing a modulation of the illumination light through operation of the movable mirrors;

a light source control unit performing a modulation control of the light source; and

a spatial light modulator control unit generating, from an input image signal, a control signal for driving the spatial light modulator, wherein;

the light source control unit controls a pulse emission frequency of an emission pulse of the illumination light emitted from the light source so that the pulse emission frequency is one-tenth an oscillation frequency of the movable mirrors or lower.

17. The projection apparatus according to claim 16, wherein:

the light source control unit drives the light source so as to change a pulse width of the emission pulse.

18. The projection apparatus according to claim 16, wherein:

the light source control unit drives the light source so as to change a pulse intensity of the emission pulse.

19. The projection apparatus according to claim 16, wherein:

the light source is a laser diode or a light emitting diode (LED).

20. The projection apparatus according to claim 16, wherein:

the movable mirrors have an ON state of reflecting, to a projection optical system, the illumination light emitted from the light source, an OFF state of reflecting the illumination light to a position that is offset from the projection optical system, and an oscillation state in which the movable mirrors oscillate between the ON state and the OFF state.

22. A projection apparatus, comprising:

a light source for emitting illumination light;

at least one spatial light modulator with a plurality of movable mirrors corresponding to pixels to be displayed, for performing a modulation of the illumination light through operation of the movable mirrors;

a light source control unit performing a modulation control of the light source; and

a spatial light modulator control unit generating, from an input image signal, a control signal for driving the spatial light modulator, wherein the light source control unit controls a pulse emission frequency of an emission pulse of the illumination light emitted from the light source by adjusting the pulse-width of the illumination light emitted from the light source to be ten times or greater than a minimum period of an ON-time of the movable mirrors.

23. The projection apparatus according to claim 22, wherein:

the light source control unit performs a control by stopping an emission of the light source during a period other than a period during a period when the control signal generated by the spatial light modulator control unit drives the spatial light modulator.

24. The projection apparatus according to claim 22, wherein:

the minimum period of the ON-time is a period controlled by a least significant bit (LSB) of a control signal received by the spatial light modulator to control the movable mirrors.

25. The projection apparatus according to claim 22, wherein:

the spatial light modulator applies a pulse-width modulation (PWM) process to control the movable mirrors.

26. The projection apparatus according to claim 22, wherein:

the light source control unit drives the light source by changing a pulse width of the emission pulse.

27. The projection apparatus according to claim 22, wherein:

the light source control unit drives the light source by changing a pulse intensity of the emission pulse.

28. The projection apparatus according to claim 22, wherein:

the light source is a laser diode or a light emitting diode (LED).

29. A projection apparatus, comprising:

a light source for emitting illumination light;

at least one spatial light modulator with a plurality of movable mirrors corresponding to pixels to be displayed, for performing a modulation of the illumination light through operation of the movable mirrors;

a light source control unit performing a modulation control of the light source; and

a spatial light modulator control unit generating, from an input image signal, a control signal for driving the spatial light modulator, wherein the light source control unit controls a pulse emission frequency of an emission pulse of the illumination light emitted from the light source by adjusting the pulse-width of the illumination light emitted from the light source to be one-tenth or less than a minimum period of an ON-time of the movable mirrors.

30. The projection apparatus according to claim 29, wherein:

the light source control unit performs a control by stopping an emission of the light source during a period other than a period during a period when the control signal generated by the spatial light modulator control unit drives the spatial light modulator.

31. The projection apparatus according to claim 29, wherein:

the minimum period of the ON-time is a period controlled by a least significant bit (LSB) of a control signal received by the spatial light modulator to control the movable mirrors.

32. The projection apparatus according to claim 29, wherein:

the spatial light modulator applies a pulse-width modulation (PWM) process to control the movable mirrors.