Multi-emitter image formation with reduced speckle

• US 20080095203A1
• Filed: 10/19/2006
• Published: 04/24/2008
• Est. Priority Date: 10/19/2006
• Status: Abandoned Application

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Islam, M. Saiful, Wang, Shih-Yuan, Bratkovski, Alexandre M.
• Application Number:
  US11/584,475
• Publication Number:
  US 20080095203A1
• Time in Patent Office: Days
• US Class Current: 372/26
• CPC Class Codes: H01S 5/423 having a vertical cavity
• CPC Class Codes: H04N 9/3129 scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161

Abstract

A technique for reducing speckle in a projected image includes forming an image using a plurality of laser light emitters. An input to the plurality of laser light emitters is non-mechanically perturbed to a degree sufficient to disrupt wavefront uniformity across the array of laser light emitters.

Claims

1. A projection system comprising:

an array of laser light emitters, each laser light emitter being capable of emitting a beam to form a portion of an image; and

a plurality of perturbation modulators non-mechanically coupled to corresponding laser light emitters to vary an input to the light emitter sufficiently to disrupt wavefront uniformity across the array of laser light emitters.

2. The system of claim 1, wherein each laser light emitter forms a single pixel of the image.

3. The system of claim 1, further comprising an optical scanning subsystem, wherein each laser light emitter is scanned to form multiple pixels of the image.

4. The system of claim 1, wherein the laser light emitter is a vertical-cavity surface-emitting laser.

5. The system of claim 1, wherein the array of laser light emitters is a plurality of vertical-cavity surface-emitting lasers fabricated on a common substrate.

6. The system of claim 1, wherein the laser light emitter comprises a red light emitter, a green light emitter, and a blue light emitter.

7. The system of claim 1, wherein the laser light emitter is an ultraviolet light emitter.

8. The system of claim 1, wherein the input is a drive current for the laser light emitter.

9. The system of claim 8, wherein the perturbation modulator comprises a chaotic signal generator to produce a chaotically varying signal as the drive current.

10. The system of claim 1, wherein the perturbation modulator comprises a mirror positioned to reflect a portion of the beam back into the laser light emitter.

11. A projection system comprising:

a plurality of means for emitting laser light to cooperatively form an image;

a means for non-mechanically perturbing the plurality of means for emitting laser light so as to disrupt wavefront uniformity across the image sufficiently to reduce speckle in the image.

12. The system of claim 11, wherein the means for non-mechanically perturbing comprises means for chaotically varying an electrical input to the means for emitting laser light.

13. The system of claim 11, wherein the means for non-mechanically perturbing comprises means for optically reflecting a portion of emitted laser light back into the means for emitting laser light.

14. A method for reducing speckle in an image projected by an array of light emitters, the method comprising:

forming an image defined at least in part by a wavefront projected by a plurality of laser light emitters driven by at least one input, each laser light emitter forming a portion of the image; and

non-mechanically perturbing the input to a degree sufficient to disrupt wavefront uniformity whereby speckle in the image is reduced.

15. The method of claim 14 wherein forming an image comprises producing a plurality of pixels of the image using one laser light emitter to produce each pixel.

16. The method of claim 14 wherein forming an image comprises producing a plurality of pixels of the image using one laser light emitter to produce a subset of N×

M of the pixels, wherein N and M are each positive integers.

17. The method of claim 14, wherein non-mechanically perturbing an input comprises electrically perturbing the input to the laser light emitters.

18. The method of claim 14 wherein non-mechanically perturbing an input comprises modulating a drive current of the plurality of laser light emitters with a chaotic signal.

19. The method of claim 14 wherein non-mechanically perturbing an input comprises optically feeding back a portion of the wavefront into the laser light emitters.