Projection display system using laser light source

• US 8,619,352 B2
• Filed: 09/05/2008
• Issued: 12/31/2013
• Est. Priority Date: 07/29/2003
• Status: Expired due to Fees

• Current Assignee: Ignite USA (Ignite)
• Original Assignee: Silicon Quest Kabushiki-Kaisha
• Inventors: Maeda, Yoshihiro, Nishino, Hirokazu, Shirai, Akira, Ichikawa, Hirotoshi, Ishii, Fusao
• Primary Examiner(s): Pham, Thomas K
• Assistant Examiner(s): THOMAS, BRANDI N
• Application Number:
  US12/231,909
• Publication Number:
  US 20090009732A1
• Time in Patent Office: 1,943 Days
• Field of Search: 359290-292, 359/295, 359/298
• US Class Current: 359/290
• 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 laser light source emitting an illumination light and a mirror device comprising a plurality of mirror elements each having a micromirror for modulating the illumination light and reflecting a modulated light to a projection lens having a depth of focus to project and focus the modulated light as an image projection light on an image display surface to display an image;

a device substrate for supporting the mirror device; and

a cover glass disposed between the mirror device and the projection lens and placed onto the device substrate covers over a top surface of the mirror device, wherein

the distance between a top surface of the mirror and the bottom surface of the cover glass facing the mirror is larger than the depth of focus of the projection lens and at least ten to one-hundred times of a size of the micromirror wherein the projection lens is disposed above the cover glass opposite the mirror device.

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

the numerical aperture of the illumination light has a numerical value ranging between 0.07 and 0.14.

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

the plurality of the mirror elements is arranged as a two-dimensional array having a diagonal size ranging between 0.4 inches and 0.87 inches.

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

the micromirror of each of the mirror elements is disposed with a gap between 0.15 and 0.55 micrometers from the micromirror of adjacent mirror elements.

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

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

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

the cover glass is further coated with a non-structured anti-reflection coating with a reflectance lower than or equal to 0.4% for the illumination light emitted from the light source.

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

the numerical aperture of the illumination light emitted from the laser light source is lower than or equal to 0.14; and

a projection magnification ratio of the projection lens has a range between 75 times and 120 times.

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

the mirror elements are arranged as an two-dimensional array.

9. A projection apparatus, comprising:

a laser light source for emitting an illumination light with adjustable light intensities and as pulsed emissions;

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

a package for containing and protecting the mirror device; and

a projection lens having a depth of focus for projecting and focusing the reflected light reflected from the mirror device on an image display surface, wherein

the package comprises a transparent cover glass covering over the mirror device and disposed between the mirror device and the projection lens; and

the distance between the bottom surface of the cover glass facing the mirror device and a top surface of the mirror of the mirror device is larger than the depth of focus of the projection lens and at least ten to one-hundred times of a size of the micromirror wherein the projection lens is disposed above the cover glass opposite the mirror device.

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

the deflection angle of the mirror is smaller than or equal to 8 degrees relative to a horizontal direction of the mirror.

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

the laser light source is a laser light source for emitting the adjustable light intensities of 3 watts or more, and

the plurality of mirror elements are arranged as a two-dimensional array having a diagonal size ranging between 0.4- and 0.87 inches.

12. The projection apparatus according to claim 9, further comprising:

a thermal conduction member is disposed on the bottom surface of the device substrate, and

the package substrate further comprising an opening part for externally exposing the thermal conduction member to radiate heat from the mirror device through the opening part.

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

the thermal conduction member protruding around the opening part and concealing the opening part.

14. The projection apparatus according to claim 9 further comprising:

an anti-reflection coating layer disposed on the cover glass.

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

the cover glass has a thickness smaller than or equal to 1 mm.

16. A projection apparatus, comprising:

a light source for emitting an illumination light;

a device substrate for supporting a mirror device wherein the mirror device comprising mirror elements, each includes a mirror for reflecting and modulating the illumination light fore projecting a modulated light to a projection lens having a depth of focus for projecting and focusing the modulated light on an image display surface to display an image;

a glass cover covers the mirror device and disposed between the mirror and the projection lens wherein

a distance between a top surface of the mirror and the bottom surface of the glass cover facing the mirror device is smaller than the depth of focus of the projection lens and at least ten to one-hundred times of a size of the micromirror wherein the projection lens is disposed above the cover glass opposite the mirror device.