Methods and apparatus for image projection

• US 5,614,961 A
• Filed: 05/22/1995
• Issued: 03/25/1997
• 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 F., Arbeiter, James H., Gibeau, Frank C.
• Primary Examiner(s): Lee, Michael
• Application Number:
  US08/447,104
• Time in Patent Office: 673 Days
• Field of Search: 348/750, 348/756, 348/758, 348/195-205
• 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;

means for modulating each parallel traveling light beamlet; and

a plurality of rotating reflective surfaces for horizontally scanning the modulated parallel traveling light beamlets for projection 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, each successive rotating reflective surface operative to horizontally scan and to vertically displace the modulated parallel traveling light beamlets with respect to the modulated parallel traveling light beamlets reflected from the preceding rotating reflective surface.

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

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

10. 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.

2. 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 a linear array of semiconductor laser diodes;

means for modulating each parallel traveling light beamlet; and

a plurality of surfaces for scanning the modulated parallel traveling white light beamlets, each successive scan of modulated parallel traveling white light beamlets vertically displaced from a previous scan of modulated parallel traveling white light beamlets, each surface operative to alter a direction of travel of the modulated parallel traveling white light beamlets, the plurality of surfaces rotating about a common axis.

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, wherein the plurality of primary wavelength light sources includes 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 beamlets;

means for modulating each parallel traveling light beamlet; and

a plurality of surfaces for horizontally scanning the modulated parallel traveling white light beamlets, each successive horizontal scan of modulated parallel traveling white light beamlets vertically displaced from a previous scan of modulated parallel traveling white light beamlets, each surface operative to alter a direction of travel of the modulated parallel traveling white light beamlets, the plurality of surfaces rotating about a common axis.

4. The image projection apparatus of claim 3, wherein said means for combining 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.

7. The image projection apparatus of claim 3, wherein the plurality of surfaces scans a fixed preselected number of pixels on an image receptor independent of image format, further comprising:

means for receiving a signal in a first 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.

5. An image projection apparatus, comprising:

a plurality of primary wavelength light sources for generating a plurality of parallel traveling light beamlets, each primary wavelength source including a linear array of semiconductor laser diodes for generating parallel traveling light beamlets wherein the plurality of primary wavelength light sources includes a red light linear array for generating a plurality of red light beamlet, a blue light linear array for generating a plurality of blue light beamlet, a green light linear array for generating a plurality of green light beamlet, and means for combining the red, green and blue beamlets into parallel traveling light beam, said plurality of primary wavelength light beam 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 of at least one primary wavelength light source;

means for modulating each parallel traveling light beamlet; and

a plurality of surfaces for scanning the modulated parallel traveling white light beamlets, each successive scan of parallel traveling white beamlets vertically displaced from a previous scan of parallel traveling white beamlets, each surface operative to alter a direction of travel of the modulated parallel traveling white beamlets, the plurality of surfaces rotating about a common axis.

6. An image projection apparatus, comprising:

a plurality of primary wavelength light sources for generating a plurality of parallel traveling light beamlets, the light sources including a plurality of semiconductor laser diodes operative to emit light beamlets;

a pulse width modulator for varying the amount of energy emitted from each semiconductor laser diode; and

a plurality of surfaces for scanning the modulated parallel traveling white light beamlets, each successive horizontal scan of modulated parallel traveling white light beamlets vertically displaced from a previous scan of modulated parallel traveling white light beamlets, each surface operative to alter a direction of travel of the modulated parallel traveling white light beamlets, the plurality of surfaces rotating about a common axis.

11. 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 at a third primary color;

modulating each of the plurality of parallel traveling light beamlets; and

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

horizontally scanning the modulated parallel traveling white light beamlets with a plurality of surfaces rotated about a common axis, each successive horizontal scan of modulated parallel traveling white light beamlets vertically displaced from a previous scan of modulated parallel traveling white light beamlets.

12. The method of claim 11, wherein the image receptor is an eye, further comprising the step of:

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

13. 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;

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 each of the beamlets of the first, second and third primary colors in response to the digital signals; and

a plurality of surfaces for horizontally scanning the modulated parallel traveling white light beamlets, each successive horizontal scan of modulated parallel traveling white beamlets vertically displaced from a previous scan of modulated parallel traveling white beamlets, each surface operative to alter a direction of travel of the modulated parallel traveling white beamlets, the plurality of surfaces rotating about a common axis.

14. 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;

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

a plurality of surfaces for horizontally scanning the modulated parallel traveling white light beamlets, each successive horizontal scan of parallel traveling white light beamlets vertically displaced from a previous scan of parallel traveling white light beamlets, each surface operative to alter a direction of travel of the modulated parallel traveling white light beamlets, the plurality of surfaces rotating about a common axis.

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

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, the successive rotating reflective surface operative to horizontally scan the modulated parallel traveling light beamlets and to vertically displace the modulated parallel traveling light beamlets with respect to the modulated parallel traveling light beamlets horizontally scanned by the preceding rotating reflective surface; and

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

16. 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; and

a plurality of surfaces for horizontally scanning the modulated parallel traveling white light beamlets, each successive horizontal scan of modulated parallel traveling white light beamlets vertically displaced from a previous scan of modulated parallel traveling white light beamlets, each surface operative to alter a direction of travel of the modulated parallel traveling white light beamlets, the plurality of surfaces rotating about a common axis.

17. The image projection apparatus of claim 16, further comprising:

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

18. The image projection apparatus of claim 16, further comprising:

a reflective screen.

19. The image projection apparatus of claim 16, wherein the modulation means comprises:

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

20. 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, the modulation means including at least one Mach-Zehnder interferometer per beamlet; and

a plurality of surfaces for scanning the modulated parallel traveling white light beamlets, each successive horizontal scan of modulated parallel traveling white light beamlets vertically displaced from a previous scan of modulated parallel traveling white light beamlets, each surface operative to alter a direction of travel of the modulated parallel traveling white light beamlets, the plurality of surfaces rotating about a common axis.

21. An image projection apparatus, comprising:

a plurality of light sources for generating a plurality of parallel traveling light beamlets;

means for pulse width modulating each parallel traveling light beamlet; and

a plurality of surfaces for horizontally scanning the modulated parallel traveling white light beamlets, each successive horizontal scan of parallel traveling white beamlets vertically displaced from a previous scan of parallel traveling white beamlets, each surface operative to alter a direction of travel of the modulated parallel traveling white beamlets, the plurality of surfaces rotating about a common axis.