Projection display system using laser light source

• US 20090009732A1
• Filed: 09/05/2008
• Published: 01/08/2009
• Est. Priority Date: 07/29/2003
• Status: Active Grant

• Current Assignee: Ignite USA (Ignite)
• Original Assignee: Olympus Corporation, Silicon Quest Kabushiki-Kaisha
• Inventors: Nishino, Hirokazu, Maeda, Yoshihiro, Ichikawa, Hirotoshi, Shirai, Akira, Ishii, Fusao
• Granted Patent: US 8,619,352 B2
• Time in Patent Office: Days
• US Class Current: 353/99
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: H01L 2924/16195 Flat cap [not enclosing an internal cavity]

Abstract

The present invention provides a projection apparatus that includes a mirror element and a drive circuit for driving a laser light source for projecting an illumination light. The projection apparatus further includes mirror device for modulating the illumination light and a projection lens for projecting the modulated light from the mirror element. The mirror device is disposed on a device substrate and packaged in a package substrate made of a transparent silicon material with a metallic thermal transfer path connected to the device substrate and a cover glass covering the package substrate. The distance between the mirror and the bottom surface of the cover glass is larger than the focal length of the projection lens.

Claims

1. A projection apparatus, comprising:

a mirror element comprising a drive circuit for driving a laser light source emitting an illumination light and comprising a mirror for modulating the illumination light;

a projection lens for projecting the modulated light from the mirror element;

a device substrate for retaining the mirror element; and

a cover glass so placed as to cover the mirror, wherein

the distance between the mirror and the bottom surface of the cover glass is larger than the depth of focus of the projection lens.

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

the numerical aperture of the light flux of the illumination light is any value between 0.07 and 0.14.

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

a plurality of the mirror elements is an array arranged in two dimensions and the diagonal size of the array is any size between 0.4 inches and 0.87 inches.

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

the mirror elements form an array arranged in two dimensions and the gap between the adjacent mirrors is any value between 0.15- and 0.55 micrometers.

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

the device substrate is made of a glass or silicon material.

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

a non-structured anti-reflection coating with which the reflectance of a laser light emitted from the laser light source is no higher than 0.4% is applied to the cover glass.

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

the numerical aperture of the flux of light emitted from the laser light source is no larger than 0.14; and

a projection magnification ratio performed by the projection lens is anywhere between 75× and

120×

.

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

the mirror elements form an array arranged in two dimensions and the difference, on both ends of the array, in the distances between the mirror and the bottom surface of the cover glass is no more than the above-mentioned depth of focus.

9. A projection apparatus, comprising:

a laser light source with variable light intensities and capability of pulse emission;

a mirror device comprising mirror elements, each of which includes both a mirror for reflecting the illumination light emitted from the laser light source and an elastic hinge for supporting the aforementioned mirror, on a device substrate;

a package for protecting the mirror device; and

a projection lens for projecting the reflected light reflected by the mirror device, wherein the package comprises both a package substrate for supporting the device substrate of the mirror device and a transparent cover glass for sealing the device substrate between the package substrate and the cover glass, and

the distance between the bottom surface of the cover glass and the mirror of the mirror device is larger than the depth of focus of the projection lens.

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

the deflection angle of the mirror is no larger than 8 degrees relative to the horizontal state of the mirror.

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

the laser light source is a laser light source for emitting light in the output of 3 watts or more, and

the diagonal size of a mirror array in which a plurality of the mirror element is arranged in a two-dimension array is any size between 0.4- and 0.87 inches.

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

a thermal conduction member is equipped on the bottom surface of the device substrate, an opening part for externally exposing the thermal conduction member is equipped on the package substrate, wherein heat is radiated from the mirror device by way of the opening part.

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

the thermal conduction member protruding from the opening part so that the aforementioned opening part is concealed.

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

an anti-reflection coating layer, which possesses the lowest reflectance for the wavelength of a laser light emitted from the laser light source, is provided on the cover glass.

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

the thickness of the cover glass is no more than 1 mm.

16. A projection apparatus, comprising:

an illumination optical system for irradiating the illumination light emitted from a laser light source;

a mirror device which includes both a drive circuit for driving the laser light source and a mirror for modulating the illumination light and which is covered with a cover glass; and

a projection optical system for projecting the modulated light incoming from the mirror device, wherein

an anti-reflection coating layer, which possesses the optimal light transmission for the wavelength of the illumination light, is formed on the cover glass placed outside of the range of the depth of focus of the projection lens.

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

the anti-reflection coating layer has the highest light transmission for the wavelength of the laser light source.

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

the anti-reflection coating layers are formed respectively on both surfaces of the cover glass.

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

at least one of the anti-reflection coating layers is a single layer.

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

the numerical aperture of the light flux of the illumination light is any value between 0.07 and 0.14.