PROJECTION APPARATUS USING SOLID-STATE LIGHT SOURCE ARRAY

• US 20090122272A1
• Filed: 11/09/2007
• Published: 05/14/2009
• Est. Priority Date: 11/09/2007
• Status: Abandoned Application

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Metzger, Robert, Bietry, Joseph R., Silverstein, Barry D.
• Application Number:
  US11/937,729
• Publication Number:
  US 20090122272A1
• Time in Patent Office: Days
• US Class Current: 353/81
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0057 in the form of a laser diode array, e.g. laser diode bar semiconductor laser arrays with beam combining arrangement H01S5/4012
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 27/0905 Dividing and/or superposing multiple light beams
• CPC Class Codes: G02B 27/0972 Prisms prisms per se G02B5/04
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: H01S 5/005 Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping H01S5/026, H01S5/18388 take precedence
• CPC Class Codes: H01S 5/4012 Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms
• CPC Class Codes: H04N 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129

Abstract

An illumination apparatus for a digital image projector, the illumination apparatus has a plurality of solid-state laser arrays, each laser array with one or more rows of laser. A light combiner has an output optical axis and a plurality of light-redirecting prisms arranged in a stack. Each light-redirecting prism has at least one contact surface that extends parallel to the output optical axis and is in optical contact with an adjacent prism in the stack and a light redirecting facet that is disposed at an oblique angle to the at least one contact surface.

Claims

1. An illumination apparatus for a digital image projector, the illumination apparatus comprising:

a) a plurality of solid-state laser arrays, each laser array comprising one or more rows of lasers; and

b) a light combiner having an output optical axis and comprising a plurality of light-redirecting prisms arranged in a stack, each light-redirecting prism comprising;

(i) at least one contact surface that extends parallel or substantially parallel to the output optical axis and is in optical contact with an adjacent prism in the stack; and

(ii) a light redirecting facet that is disposed at an oblique angle to the at least one contact surface.

2. The illumination apparatus of claim 1 wherein each light-redirecting prism has an output surface that is substantially orthogonal to its at least one contact surface.

3. The illumination apparatus of claim 1 wherein the lasers are vertical-cavity devices.

4. The illumination apparatus of claim 1 wherein the light-redirecting facets provide total internal reflection for incident light.

5. The illumination apparatus of claim 1 wherein at least one light-redirecting facet is a coated thin film structure.

6. The illumination apparatus of claim 1 wherein at least one light-redirecting facet is a coated metal film.

7. The illumination apparatus of claim 2 further comprising a coating on at least one of the at least one light redirecting facet and the output surface.

8. The illumination apparatus of claim 7 wherein the coating is taken from the group consisting of an antireflection coating and an IR rejection coating.

9. The illumination apparatus of claim 1 further comprising a spatial light modulator in the path of light from the output surface.

10. The illumination apparatus of claim 9 wherein the output surface has an aspect ratio that is within ±

0.3 of the aspect ratio of the spatial light modulator.

11. The illumination apparatus of claim 2 further comprising a waveguide for directing light from the output surface.

12. The illumination apparatus of claim 2 further comprising an optical integrator for receiving light from the output surface.

13. The illumination apparatus of claim 11 wherein the waveguide is an optical fiber.

14. The projection apparatus of claim 9 wherein the spatial light modulator is taken from the group consisting of a digital micromirror device and a liquid-crystal-on-silicon device.

15. The projection apparatus of claim 2 further comprising at least one polarization beamsplitter in the path of the redirected light from the output surface.

16. The projection apparatus of claim 15 further comprising a half-wave plate in the path of light that is redirected through the at least one polarization beamsplitter.

17. An illumination apparatus for a digital image projector, the illumination apparatus comprising:

a) a plurality of solid-state laser arrays, each laser array comprising one or more rows of lasers; and

b) a light combiner having an output optical axis and comprising a plurality of light-redirecting prisms arranged in a stack, each light-redirecting prism comprising;

i) at least one contact surface that extends perpendicular or substantially perpendicular to the output optical axis and is in optical contact with an adjacent prism in the stack; and

ii) a light redirecting facet that is disposed at an oblique angle to the at least one contact surface.

18. The illumination apparatus of claim 17 wherein each light-redirecting prism has an output surface that is substantially perpendicular to its at least one contact surface.

19. An illumination apparatus for a digital image projector, the illumination apparatus comprising:

a plurality of solid-state laser arrays, each laser array comprising one or more rows of lasers, the rows extending in a length direction, and each laser in the laser arrays disposed to direct light in an emission direction that is orthogonal to the length direction; and

a light-redirecting prism comprising a plurality of incidence facets disposed on two sides of the light-redirecting prism and wherein the plurality of light-redirecting facets are also disposed on the same two sides of the light-redirecting prism.

20. The illumination apparatus as described in claim 19 wherein the pattern of incident facets and light redirecting facets from opposing sides forms an offset symmetry.