Methods and apparatus for image projection

• US 5,715,021 A
• Filed: 12/15/1995
• Issued: 02/03/1998
• Est. Priority Date: 02/03/1993
• Status: Expired due to Term

• Current Assignee: Prysm Systems, Inc.
• Original Assignee: Nitori Company Limited (Nitori Holdings Company Limited)
• Inventors: Bessler, Roger Frank, Arbeiter, James Henry, Gibeau, Frank C.
• Primary Examiner(s): LEE, MICHAEL
• Application Number:
  US08/573,511
• Time in Patent Office: 781 Days
• Field of Search: 348/754-757, 348/769-772, 348/750, 348/190-205
• US Class Current: 348/750
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 26/123 Multibeam scanners, e.g. using multiple light sources or beam splitters
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• 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
• CPC Class Codes: H04N 9/3132 using one-dimensional electronic spatial light modulators

Abstract

Method and apparatus for a multi-application, laser-array-based image system utilizes three linear laser arrays. Each linear array generates multiple (N>1) parallel output beamlets at one of the three primary colors (red, green, blue). The corresponding 1 to N output beamlets of the three linear arrays, each individually modulated in luminance according to a specific encoding scheme representing the video image to be produced on the viewing screen, are combined spatially to form a single white light linear array source. Through a projection/scanner optical system, the N output beamlets of the white light source are simultaneously directed to, and swept horizontally across a distant viewing screen, resulting in a swath of N lines of a graphic video image. By producing M contiguous swaths vertically down the viewing screen, a full image of M×N lines is produced. The red, green, and blue linear laser arrays may consist of arrays of semiconductor laser diodes made of suitable semiconductor materials so as to directly emit radiation at wavelengths corresponding to red, green, and blue colors, respectively. Alternatively, the red, green and blue color arrays may be formed by arrays of semiconductor laser diodes emitting radiation at twice the desired red, green and blue wavelengths, whose radiation is coupled to arrays of second harmonic generation crystal elements.

Claims

1. An image projection apparatus, comprising:

a plurality of primary wavelength light sources for generating a plurality of parallel traveling light beamlets, the plurality of primary wavelength light sources including at least one non-linear harmonic converter for multiplying the frequency of light beamlets generated by a linear array of semiconductor laser diodes;

means for modulating the parallel traveling light beamlets; and

a plurality of rotating reflective surfaces for scanning and projecting the modulated parallel traveling light beamlets onto an image receptor, each successive rotating reflective surface adjacent to and skewed from a preceding rotating reflective surface, all of the plurality of rotating reflective surfaces rotationally driven at the same angular velocity.

2. The image projection apparatus of claim 1, further comprising:

a galvanometer operative to deflect each of the parallel traveling light beamlets to provide at least one interlaced field within a frame.

3. An image projection apparatus, comprising:

a plurality of primary wavelength light sources for generating a plurality of parallel traveling light beamlets, each primary wavelength light source including a linear array of semiconductor laser diodes for generating parallel traveling light beamlets, the plurality of primary wavelength light sources including at least one non-linear harmonic converter for multiplying the frequency of light beamlets generated by the linear array of semiconductor laser diodes;

means for modulating the parallel traveling light beamlets; and

means for scanning and projecting the modulated parallel traveling light beamlets to generate pixels onto an image receptor.

4. The image projection apparatus of claim 3, wherein the plurality of primary wavelength light sources further comprises:

a red light linear array for generating a plurality of red light beamlets;

a blue light linear array for generating a plurality of blue light beamlets;

a green light linear array for generating a plurality of green light beamlets; and

means for combining the red, green and blue beamlets into parallel traveling light beams.

5. The image projection apparatus of claim 4, wherein said means for combining further comprises:

a mirror for reflecting each beamlet of one of the red, green and blue plurality of light beamlets;

a first dichroic filter for transmitting each beamlet of the plurality of light beamlets reflected by the mirror and spatially combining each such beamlet with each corresponding beamlet of one of the two remaining pluralities of light beamlets; and

a second dichroic filter for spatially combining each combined beamlet from the first dichroic filter with each corresponding beamlet of the one remaining plurality of light beamlets.

6. The image projection apparatus of claim 3, wherein:

a complete image projected onto an image receptor is formed by a single scan of parallel traveling light beamlets.

7. The image projection apparatus of claim 3, wherein the means for scanning and projecting the modulated parallel traveling light beamlets scans and projects a fixed preselected number of pixels on the image receptor independent of an input image format, and further comprises:

means for receiving a signal in the input image format, the signal containing image data the image data corresponding to a first number of pixels; and

remapping means for selecting from the first number of pixels a second number of pixels as at least a portion of the fixed preselected number of pixels for scanning and projection, the remapping means including interpolation means for generating additional pixels from the image data when the fixed preselected number of pixels exceeds the first number of pixels.

8. The image projection apparatus of claim 7, wherein said means for remapping comprises:

a serial to parallel converter.

9. The image projection apparatus of claim 3, wherein said means for scanning and projecting further comprises:

at least one lens; and

at least one mirror.

10. The image projection apparatus of claim 3, further comprising:

a galvanometer operative to deflect the modulated parallel traveling light beamlets.

11. An image projection apparatus, comprising:

a plurality of primary wavelength light sources for generating a plurality of parallel traveling light beamlets, the plurality of primary wavelength light sources including at least one non-linear harmonic converter for multiplying the frequency of light beamlets generated by a linear array of semiconductor laser diodes;

a pulse width modulator for varying the amount of energy emitted from each primary wavelength light source; and

means for scanning and projecting the modulated parallel traveling light beamlets to generate pixels on an image receptor.

12. A method of projecting an image, comprising the steps of:

providing a plurality of parallel traveling light beamlets of a first primary color;

providing a plurality of parallel traveling light beamlets of a second primary color;

providing a plurality of parallel traveling light beamlets of a third primary color by multiplying with at least one non-linear harmonic converter the frequency of light beamlets generated by a linear array of semiconductor laser diodes;

modulating the plurality of parallel traveling light beamlets;

combining the modulated parallel traveling light beamlets to form a plurality of modulated parallel white light beamlets;

reflecting the modulated parallel white beamlets from a plurality of rotating reflective surfaces onto an image receptor, each successive rotating reflective surface adjacent to and skewed from a preceding rotating reflective surface; and

rotationally driving all of the plurality of rotating reflective surfaces at the same angular velocity.

13. The method of claim 12 wherein the image receptor is an eye, further comprising the step of:

reflecting the modulated parallel white beamlets from the plurality of rotating reflective surfaces directly into the eye.

14. An image projection apparatus, comprising:

video processing means for receiving image data and generating digital red signals, digital green signals, digital blue signals and timing signals representative of image data;

a first laser array for generating a plurality of parallel traveling beamlets of a first primary color;

a second laser array for generating a plurality of parallel traveling beamlets of a second primary color;

a third laser array for generating a plurality of parallel traveling beamlets of a third primary color, the third laser array including at least one non-linear harmonic converter for multiplying the frequency of light beamlets generated by a linear array of semiconductor laser diodes;

means for combining the plurality of parallel traveling beamlets of the first, second and third primary colors to generate a plurality of parallel traveling white light beamlets;

means for digitally modulating the intensity of the beamlets of the first, second and third primary colors in response to the digital signals; and

means for scanning and projecting the plurality of parallel white light beams across a screen.

15. An image projection apparatus, comprising:

means for receiving image data and generating digital luminance signals and timing signals representative of image data;

a laser array for generating a plurality of parallel traveling light beamlets, the laser array including at least one non-linear harmonic converter for multiplying the frequency of light beamlets generated by a linear array of semiconductor laser diodes;

means for pulse width modulating the intensity of the beamlets in response to the luminance signals; and

means for scanning and projecting the plurality of parallel traveling light beamlets onto an image receptor.

16. A method of forming an image on a screen, comprising the steps of:

receiving image data representative of an image;

generating a plurality of parallel traveling light beamlets by multiplying with at least one non-linear harmonic converter the frequency of light beamlets generated by a linear array of semiconductor laser diodes;

projecting the plurality of parallel traveling light beamlets across a first area of a screen;

projecting the plurality of parallel traveling light beamlets across a second area of the screen; and

pulse width modulating the plurality of parallel traveling light beamlets with the image data.

17. A method of generating and scanning a plurality of parallel traveling light beamlets across a screen, comprising the steps of:

generating a plurality of parallel traveling light beamlets by multiplying with at least one non-linear harmonic converter the frequency of light beamlets generated by a linear array of semiconductor laser diodes;

reflecting the plurality of parallel traveling light beamlets from a plurality of rotating reflective surfaces onto an image receptor, each successive rotating reflective surface adjacent to and skewed from a preceding rotating reflective surface; and

rotationally driving all of the plurality of rotating reflective surfaces at the same angular velocity.

18. An image projection apparatus, comprising:

converter means for outputting a red digital signal, a green digital signal and a blue digital signal in response to a video signal representative of a color image;

time base correction means for correcting timing errors of the red, green and blue digital signals;

serial to parallel conversion means for generating sets of parallel data representative of the color image;

a plurality of primary wavelength light beamlet sources for generating a plurality of parallel traveling beamlets, the plurality of primary wavelength light beamlet sources including at least one nonlinear harmonic converter for multiplying the frequency of light beamlets generated by a linear array of semiconductor laser diodes;

modulation means for modulating the plurality of the parallel traveling beamlets in response to the parallel data; and

means for scanning and projecting the modulated parallel traveling beamlets.

19. The image projection apparatus of claim 18, further comprising:

image resizing means for spatially remapping the red, green and blue digital signals from a first format to a second format.

20. The image projection apparatus of claim 18, further comprising:

a reflective screen.

21. The image projection apparatus of claim 18, wherein the modulation means further comprises:

a pulse width modulator for generating groups of pulses, each group of pulses having an energy content corresponding to the luminance of at least one of the first, second and third primary colors within one pixel of the color image.

22. The image projection apparatus of claim 18, wherein the modulation means comprises:

at least one Mach-Zehnder interferometer per beamlet.

23. An image projection apparatus, comprising:

a plurality of light sources for generating a plurality of parallel traveling light beamlets, the plurality of light sources including at least one non-linear harmonic converter for multiplying the frequency of light beamlets generated by a linear array of semiconductor laser diodes;

means for pulse width modulating the parallel traveling light beamlets; and

means for scanning and rastering the modulated parallel light beamlets to generate pixels onto an image receptor.

24. An image projection apparatus, comprising:

a plurality of primary wavelength light sources for generating a plurality of parallel traveling light beamlets, the plurality of primary wavelength light sources including at least one non-linear harmonic converter for multiplying the frequency of light beamlets generated by a linear array of semiconductor laser diodes;

means for modulating the primary wavelength light sources; and

a plurality of rotating reflective surfaces for scanning and projecting the modulated parallel traveling light beamlets onto an image receptor, each successive rotating reflective surface adjacent to and skewed from a preceding rotating reflective surface, all of the plurality of rotating reflective surfaces rotationally driven at the same angular velocity.

33. The image projection apparatus of claim 24, further comprising:

a galvanometer operative to deflect each of the parallel traveling light beamlets to provide at least one interlaced field within a frame.

25. An image projection apparatus, comprising:

a plurality of primary wavelength light sources for generating a plurality of parallel traveling light beamlets, each primary wavelength light source including a linear array of semiconductor laser diodes for generating parallel traveling light beamlets, the plurality of primary wavelength light sources including at least one non-linear harmonic converter for multiplying the frequency of light beamlets generated by the linear array of semiconductor laser diodes;

means for modulating the primary wavelength light sources; and

means for scanning and projecting the modulated parallel traveling light beamlets to generate pixels onto an image receptor.

26. The image projection apparatus of claim 25, wherein the plurality of primary wavelength light sources further comprises:

a red light linear array for generating a plurality of red light beamlets;

a blue light linear array for generating a plurality of blue light beamlets;

a green light linear array for generating a plurality of green light beamlets; and

means for combining the red, green and blue beamlets into parallel traveling light beams.

27. The image projection apparatus of claim 26, wherein said means for combining further comprises:

a mirror for reflecting each beamlet of one of the red, green and blue plurality of light beamlets;

a first dichroic filter for transmitting each beamlet of the plurality of light beamlets reflected by the mirror and spatially combining each such beamlet with each corresponding beamlet of one of the two remaining pluralities of light beamlets; and

a second dichroic filter for spatially combining each combined beamlet from the first dichroic filter with each corresponding beamlet of the one remaining plurality of light beamlets.

28. The image projection apparatus of claim 25, wherein:

a complete image projected onto an image receptor is formed by a single scan of parallel traveling light beamlets.

29. The image projection apparatus of claim 25, wherein the means for scanning and projecting the modulated parallel traveling light beamlets scans and projects a fixed preselected number of pixels on the image receptor independent of an input image format, and further comprises:

means for receiving a signal in the first image format, the signal containing image data the image data corresponding to a first number of pixels; and

remapping means for selecting from the first number of pixels a second number of pixels as at least a portion of the fixed preselected number of pixels for scanning and projection, the remapping means including interpolation means for generating additional pixels from the image data when the fixed preselected number of pixels exceeds the first number of pixels.

30. The image projection apparatus of claim 29, wherein said means for remapping comprises:

a serial to parallel converter.

31. The image projection apparatus of claim 25, wherein said means for scanning and projecting further comprises:

at least one lens; and

at least one mirror.

32. The image projection apparatus of claim 25, further comprising:

a galvanometer operative to deflect the modulated parallel traveling light beamlets.

34. An image projection apparatus, comprising:

converter means for outputting a red digital signal, a green digital signal and a blue digital signal in response to a video signal representative of a color image;

time base correction means for correcting timing errors of the red, green and blue digital signals;

serial to parallel conversion means for generating sets of parallel data representative of the color image;

a plurality of primary wavelength light beamlet sources for generating a plurality of parallel traveling beamlets, the plurality of primary wavelength light beamlet sources including at least one non-linear harmonic converter for multiplying the frequency of light beamlets generated by a linear array of semiconductor laser diodes;

modulation means for modulating the primary wavelength light beamlet sources in response to the parallel data; and

means for scanning and projecting the modulated parallel traveling beamlets.

35. The image projection apparatus of claim 34, further comprising:

image resizing means for spatially remapping the red, green and blue digital signals from a first format to a second format.

36. The image projection apparatus of claim 34, further comprising:

a reflective screen.

37. The image projection apparatus of claim 34, wherein the modulation means further comprises:

a pulse width modulator for generating groups of pulses, each group of pulses having an energy content corresponding to the luminance of at least one of the first, second and third primary colors within one pixel of the color image.

38. An image projection apparatus, comprising:

a plurality of light sources for generating a plurality of parallel traveling light beamlets, the plurality of light sources including at least one non-linear harmonic converter for multiplying the frequency of light beamlets generated by a linear array of semiconductor laser diodes;

means for pulse width modulating the plurality of light sources; and

means for scanning and rastering the modulated parallel light beamlets to generate pixels onto an image receptor.

39. An image projection apparatus, comprising:

a plurality of primary wavelength light sources for generating a plurality of parallel traveling light beamlets, the plurality of primary wavelength light sources;

means for modulating each parallel traveling light beamlet;

at least one non-linear harmonic converter for multiplying the frequency of at least one modulated parallel traveling light beamlet; and

a plurality of rotating reflective surfaces for scanning and projecting the modulated parallel traveling light beamlets onto an image receptor, each successive rotating reflective surface adjacent to and skewed from a preceding rotating reflective surface, all of the plurality of rotating reflective surfaces rotationally driven at the same angular velocity.

48. The image projection apparatus of claim 39, further comprising:

a galvanometer operative to deflect each of the parallel traveling light beamlets to provide at least one interlaced field within a frame.

40. An image projection apparatus, comprising:

a plurality of primary wavelength light sources for generating a plurality of parallel traveling light beamlets, each primary wavelength light source including a linear array of semiconductor laser diodes for generating parallel traveling light beamlets;

means for modulating each parallel traveling light beamlet;

at least one non-linear harmonic converter for multiplying the frequency of at least one modulated parallel traveling light beamlet; and

means for scanning and projecting the modulated parallel traveling light beamlets to generate pixels onto an image receptor.

41. The image projection apparatus of claim 40, wherein the plurality of primary wavelength light sources further comprises:

a red light linear array for generating a plurality of red light beamlets;

a blue light linear array for generating a plurality of blue light beamlets;

a green light linear array for generating a plurality of green light beamlets; and

means for combining the red, green and blue beamlets into parallel traveling light beams.

42. The image projection apparatus of claim 41, wherein said means for combining further comprises:

a mirror for reflecting each beamlet of one of the red, green and blue plurality of light beamlets;

a first dichroic filter for transmitting each beamlet of the plurality of light beamlets reflected by the mirror and spatially combining each such beamlet with each corresponding beamlet of one of the two remaining pluralities of light beamlets; and

a second dichroic filter for spatially combining each combined beamlet from the first dichroic filter with each corresponding beamlet of the one remaining plurality of light beamlets.

43. The image projection apparatus of claim 40, wherein:

a complete image projected onto an image receptor is formed by a single scan of parallel traveling light beamlets.

44. The image projection apparatus of claim 40, wherein the means for scanning and projecting the modulated parallel traveling light beamlets scans and projects a fixed preselected number of pixels on the image receptor independent of an input image format, and further comprises:

means for receiving a signal in the input image format, the signal containing image data the image data corresponding to a first number of pixels; and

remapping means for selecting from the first number of pixels a second number of pixels as at least a portion of the fixed preselected number of pixels for scanning and projection, the remapping means including interpolation means for generating additional pixels from the image data when the fixed preselected number of pixels exceeds the first number of pixels.

45. The image projection apparatus of claim 44, wherein said means for remapping comprises:

a serial to parallel converter.

46. The image projection apparatus of claim 40, wherein said means for scanning and projecting further comprises:

at least one lens; and

at least one mirror.

47. The image projection apparatus of claim 40, further comprising:

a galvanometer operative to deflect the modulated parallel traveling light beamlets.

49. A method of projecting an image, comprising the steps of:

providing a first plurality of parallel traveling light beamlets;

providing a second plurality of parallel traveling light beamlets;

providing a third plurality of parallel traveling light beamlets;

modulating each of the plurality of parallel traveling light beamlets;

multiplying with at least one non-linear harmonic converter the frequency of at least one of the pluralities of parallel traveling light beamlets;

combining the modulated parallel traveling light beamlets to form a plurality of modulated parallel white light beamlets;

reflecting the modulated parallel white beamlets from a plurality of rotating reflective surfaces onto an image receptor, each successive rotating reflective surface adjacent to and skewed from a preceding rotating reflective surface; and

rotationally driving all of the plurality of rotating reflective surfaces at the same angular velocity.

50. An image projection apparatus, comprising:

converter means for outputting a red digital signal, a green digital signal and a blue digital signal in response to a video signal representative of a color image;

time base correction means for correcting timing errors of the red, green and blue digital signals;

serial to parallel conversion means for generating sets of parallel data representative of the color image;

a plurality of primary wavelength light beamlet sources for generating a plurality of parallel traveling beamlets;

modulation means for modulating the plurality of the parallel traveling beamlets in response to the parallel data;

at least one non-linear harmonic converter for multiplying the frequency of at least one modulated parallel traveling light beamlet; and

means for scanning and projecting the modulated parallel traveling beamlets.

51. The image projection apparatus of claim 50, further comprising:

image resizing means for spatially remapping the red, green and blue digital signals from a first format to a second format.

52. The image projection apparatus of claim 50, further comprising:

a reflective screen.

53. The image projection apparatus of claim 50, wherein the modulation means further comprises:

a pulse width modulator for generating groups of pulses, each group of pulses having an energy content corresponding to the luminance of at least one of the first, second and third primary colors within one pixel of the color image.

54. The image projection apparatus of claim 50, wherein the modulation means comprises:

at least one Mach-Zehnder interferometer per beamlet.

55. An image projection apparatus, comprising:

a plurality of primary wavelength light sources for generating a plurality of parallel traveling light beamlets, each primary wavelength light source including a linear array of semiconductor laser diodes for generating parallel traveling light beamlets, the plurality of primary wavelength light sources including at least one non-linear harmonic converter for multiplying the frequency of light beamlets generated by the linear array of semiconductor laser diodes;

means for projecting the plurality of parallel traveling light beamlets across a first area of a screen and across a second area of the semen; and

a pulse width modulator for modulating plurality of parallel traveling light beamlets with image data.