Projection apparatus with coherent light source

• US 20090009851A1
• Filed: 09/05/2008
• Published: 01/08/2009
• Est. Priority Date: 11/01/2003
• Status: Active Grant

• Current Assignee: Ignite USA (Ignite)
• Original Assignee: Olympus Corporation, Silicon Quest Kabushiki-Kaisha
• Inventors: Endo, Taro, Maeda, Yoshihiro, Ichikawa, Hirotoshi, Ishii, Fusao, Horikawa, Yoshiaki
• Granted Patent: US 8,238,019 B2
• Time in Patent Office: Days
• US Class Current: 359/292
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

The present invention discloses a projection apparatus comprising: a light source for emitting illumination light; a mirror device comprising a plurality of mirrors for generating an image by reflecting the illumination light toward a projecting direction by means of a deflecting operation; and a projection optical system which is placed in the optical axis of reflection light in the projecting direction of the illumination light incident to the mirror device and which projects the reflection light, wherein the optical axis of the illumination light incident to the mirror device and the optical axis of the reflection light in the projecting direction forms an angle that is larger than the expansion angle α of the flux of the illumination light that satisfies NA=n*sin α, where NA is the numerical aperture of the flux of the illumination light, and n is the reflectance.

Claims

1. A projection apparatus comprising a light source for emitting an illumination light to a mirror device having a plurality of mirrors for modulating and reflecting the illumination light to an image projection optical system for displaying an image, wherein:

an optical axis of the illumination light incident to the mirror device and an optical axis of the reflection light in the projecting direction forms an angle larger than an expansion angle α

of the illumination light wherein;

NA=n*sin α

,

where NA is a numerical aperture of the illumination light, and n is a reflectance of the mirror device.

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

the light source is a laser light source.

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

the light source includes a plurality of laser light sources.

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

the mirror performs a deflecting operation on the basis of a deflection axis going through an approximate center of the present mirror.

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

the mirror performs a deflecting operation on the basis of a deflection axis going through an edge of the present mirror.

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

the mirror device comprises at least one electrode for each of the mirrors in order to control the deflecting operation.

7. The projection apparatus according to claim 1, wherein the deflecting operation of the mirror of the mirror device includes:

an ON state for guiding the reflection light to the projection optical system;

an OFF state for guiding the reflection light away from the projection optical system; and

an oscillation state for oscillating the mirror between the ON state and OFF state, wherein the reflection light incident to the projection optical system from the mirror device is used for a display in the oscillation state.

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

the deflection angle of the mirror is symmetrical between the clockwise (CW) direction and counterclockwise (CCW) direction relative to the initial state of the mirror.

9. The projection apparatus according to claim 8, wherein:

the deflection angle of the mirror in the CW direction is an angle between 3 degrees and 13 degrees, and

the deflection angle of the mirror in the CCW direction is an angle between −

13 degrees and −

3 degrees,

where the CW direction is defined as positive and the CCW direction as negative (−

), with the initial state of the mirror defined as “

0”

degrees.

10. The projection apparatus according to claim 8, wherein;

the deflection angle of the mirror in the CW direction is larger than 3 degrees, and

the deflection angle of the mirror in the CCW direction is smaller than −

3 degrees,

where the CW direction is defined as positive and the CCW direction as negative (−

), with the initial state of the mirror defined as “

0”

degrees.

11. The projection apparatus according to claim 8, wherein:

the deflection angle of the mirror in the CW direction is approximately 13 degrees, and

the deflection angle of the mirror in the CCW direction is approximately −

13 degrees,

where the CW direction is defined as positive and the CCW direction as negative (−

), with the initial state of the mirror defined as “

0”

degrees.

12. The projection apparatus according to claim 8, wherein:

the deflection angle of the mirror in the CW direction is larger than 13 degrees, and

the deflection angle of the mirror in the CCW direction is smaller than −

13 degrees,

where the CW direction is defined as positive and the CCW direction as negative (−

), with the initial state of the mirror defined as “

0”

degrees.

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

the deflection angle of the mirror is asymmetrical between the clockwise (CW) direction and counterclockwise (CCW) direction relative to the initial state of the mirror.

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

the deflection angle of the mirror in the CW direction is an angle between 3 degrees and 13 degrees, and

the deflection angle of the mirror in the CCW direction is an angle between −

13 degrees and −

3 degrees,

where the CW direction is defined as positive and the CCW direction as negative (−

), with the initial state of the mirror defined as “

0”

degrees.

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

the deflection angle of the mirror in the CW direction is larger than 13 degrees, and

the deflection angle of the mirror in the CCW direction is smaller than −

13 degrees,

where the CW direction is defined as positive and the CCW direction as negative (−

), with the initial state of the mirror defined as “

0”

degrees.

16. A projection apparatus comprising:

a light source for emitting illumination light;

a mirror device comprising a plurality of mirrors for generating an image by reflecting the illumination light toward a projecting direction by means of a deflecting operation; and

a projection optical system which is placed in the optical axis of reflection light in the projecting direction of the illumination light incident to the mirror device and which projects the reflection light, wherein

the deflection angle of the mirror device is set in a manner so that the contrast ratio of a video image projected onto a screen from the projection optical system is larger than the contrast ratio of a video image projected by the projection optical system when an angle formed by

the optical axis of the illumination light incident to the mirror device and the optical axis of the reflection light in the projecting direction is approximately equal to the expansion angle α

of the flux of the illumination light that satisfies

NA=n*sin α

,

where NA is the numerical aperture of the flux of the illumination light, and n is the reflectance.

17. A projection apparatus comprising:

a light source for emitting illumination light;

a mirror device comprising a plurality of mirrors for generating an image by reflecting the illumination light toward a projecting direction by means of a deflecting operation; and

a projection optical system which is placed in the optical axis of reflection light in the projecting direction of the illumination light incident to the mirror device and which projects the reflection light, wherein

the expansion angle α

of the illumination light is set in a manner so that the contrast ratio of a video image projected onto a screen from the projection optical system is larger than the contrast ratio of a video image projected by the projection optical system when an angle formed by

the optical axis of the illumination light incident to the mirror device and the optical axis of the reflection light in the projecting direction is approximately equal to the expansion angle α

of the flux of the illumination light that satisfies

NA=n*sin α

,

where NA is the numerical aperture of the flux of the illumination light, and N is the reflectance.

18. A color projection apparatus comprising:

a light source;

color separation means for separating the light from the light source into a plurality of illumination lights with respective colors;

a plurality of mirror devices each comprising a plurality of mirrors for reflecting the illumination light toward a projecting direction by performing a deflecting operation, thereby generating an image;

color synthesis means for synthesizing the reflection lights, in the projecting direction, of the illumination light incident to a plurality of the mirror devices; and

a projection optical system which is placed approximately in the optical axis of the synthesized light output from the color synthesis means and which projects the synthesized light output therefrom, wherein

the optical axis of the illumination light incident to the mirror device and the optical axis of the reflection light in the projecting direction forms an angle that is larger than the expansion angle α

of the flux of the illumination light that satisfies

NA=n*sin α

,

where NA is the numerical aperture of the flux of the illumination light, and n is the reflectance.

19. The color projection apparatus according to claim 18, wherein

the color separation means and the color synthesis means exist in different region approximately on the same plane.