Projection method for reducing interpixel gaps on a viewing surface

• US 8,702,248 B1
• Filed: 06/11/2009
• Issued: 04/22/2014
• Est. Priority Date: 06/11/2008
• Status: Expired due to Fees

• Current Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Original Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Inventors: Christensen, Robert R., Elkins, Dennis F.
• Primary Examiner(s): CHOWDHURY, SULTAN U.
• Application Number:
  US12/483,225
• Time in Patent Office: 1,776 Days
• Field of Search: 353/30, 353/31, 353/37, 353/38, 353/85, 353/94, 353/97, 353/99, 348/750, 348/679, 348/743, 348/744, 348/E9.027, 349/196.1, 349/199.2, 349/201.2, 349/202.1, 349/204.2, 349/237, 349/242, 349/249, 349/5, 349 7- 9, 372/22, 372/26, 372/28, 359/196.1, 359/199.2, 359/201.2, 359/202.1, 359/204.2, 359/237, 359/242, 359/249
• US Class Current: 353/99
• 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 display system able to reduce interpixel intensity gaps caused by the use of pulsed laser sources having relatively short optimum pulse duration. The interpixel intensity gaps are reduced by temporally offsetting multiple laser pulses for a display pixel during a corresponding pixel-scan period. The temporally offset pulses for the display pixel are then scanned to different locations on a viewing surface such that the display pixel has an improved intensity distribution. Additional reduction in the interpixel gaps may be accomplished by de-focusing the temporally offset pulses in a scan direction, increasing the duty cycle of the source lasers, and shifting the location of alternating frames on the viewing surface.

Claims

1. A method for generating an image on a viewing surface, said method comprising:

(a) pulsing temporally offset beams of light onto a pixel element of a light modulator during a pixel-scan period for a display pixel;

(b) causing each of the temporally offset beams of light to be out of focus on said pixel element;

(c) modulating said temporally offset and out of focus beams of light with the pixel element; and

(d) scanning a desired portion of said temporally offset beams of light, as modulated by the pixel element, onto the viewing surface to thereby form the display pixel.

2. The method of claim 1, wherein step (d) comprises scanning the temporally offset beams of light, as modulated by the pixel element, to spatially offset locations on the viewing surface.

3. The method of claim 1, wherein step (d) comprises scanning the temporally offset beams of light, as modulated by the pixel element, with a moving reflective member.

4. The method of claim 1, wherein step (a) comprises pulsing each of the temporally offset beams of light from a unique light source.

5. The method of claim 1, wherein step (a) comprises pulsing each of the temporally offset beams of light for a duration less than about 50% of the pixel-scan period.

6. The method of claim 1, wherein step (a) comprises pulsing each of the temporally offset beams of light for a duration less than about 40% of the pixel-scan period.

7. The method of claim 1, wherein step (a) comprises pulsing each of the temporally offset beams of light during non-overlapping time intervals of the pixel-scan period.

8. The method of claim 1, wherein step (a) comprises pulsing at least three temporally offset beams of light during the pixel-scan period.

9. The method of claim 1, wherein step (a) comprises pulsing temporally offset beams of light of a same color onto the pixel element of the light modulator during the pixel-scan period for the display pixel.

10. The method of claim 1, wherein step (c) comprises modulating said temporally offset beams of light using diffraction.

11. The method of claim 1, wherein die pixel element comprises at least two deflectable and elongated elements.

12. The method of claim 1, wherein said pixel element forms part of a one-dimensional array of pixel elements on the light modulator.

13. The method a claim 1, further comprising collimating each of the temporally offset beams of light in a second direction prior to said pixel element.

14. A method for generating an image on a viewing surface, said method comprising:

(a) scanning modulated light from a one-dimensional array of pixel elements on a light modulator to thereby form a first frame of an image on the viewing surface;

(b) scanning modulated light from the one-dimensional array of pixel elements on the light modulator to thereby form a second frame of an image on the viewing surface; and

(c) offsetting spatially the first frame and the second frame on the viewing surface, wherein the step of offsetting spatially the first frame comprises initiating a scan of the first frame when a scanning device is at a first position of a sweep of the viewing surface and initiating a scan of the second frame when said scanning device is at a second position of a sweep of the viewing outface.

15. The method of claim 14, wherein step (c) comprises offsetting the first frame and the second frame by less than one pixel width.

16. The method of claim 14, wherein step (c) comprises offsetting the first frame and the second frame by approximately one-half of a pixel width.

17. The method of claim 14, wherein said second position is past said first position in the sweep of the viewing surface.