Large screen video display systems and methods therefor
First Claim
1. A large area, flat screen, display system for video signal information comprising:
- large area, flat, rear projection screen means;
means disposed adjacent said screen means for generating a small diameter, collimated beam of light;
beam modulating means disposed in the path of the beam for modulating the beam in response to video signals while maintaining the beam diameter and collimation;
beam scanning means positioned adjacent said screen means and in the path of said beam subsequent to the beam modulating means for scanning said beam through a display raster within an expanding beam envelope; and
optical path folding means comprising spaced apart reflecting elements mounted rearwardly of and adjacent to said screen means and positioned to establish a path for the expanding beam envelope that traverses behind said screen means in at least two path segments, the final path segment directing the beam against said projection screen means with substantially varying angles and throw distances within the envelope.
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Accused Products
Abstract
A large screen display system for video modulated collimated light provides superior contrast and brightness, in a shallow depth configuration if desired. A single modulated laser beam which may have different color components is raster scanned, defining a beam envelope which is then expanded along an adequately long optical path length within a confined volume and directed toward a display screen on which the beam impinges. The optical system may selectively redirect the available light energy into a viewing volume with optical gain and with high contrast. In a particularly compact example of a rear projection system, the optical path is defined by successive reflecting elements adjacent and substantially coextensive with the screen, which cause the beam path to traverse behind the screen in successive path segments. The beam envelope is then directed obliquely against the display plane, but differentially redirected so as to be transmitted orthogonally outwardly. Optical gain may be further improved by an array of lens elements at the display plane defining diffuse point light sources to an observer, and the lens elements further may anistropically shape the far field distribution of the light. Light absorbing means disposed at the display plane can be used to enhance color contrast substantially.
79 Citations
31 Claims
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1. A large area, flat screen, display system for video signal information comprising:
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large area, flat, rear projection screen means; means disposed adjacent said screen means for generating a small diameter, collimated beam of light; beam modulating means disposed in the path of the beam for modulating the beam in response to video signals while maintaining the beam diameter and collimation; beam scanning means positioned adjacent said screen means and in the path of said beam subsequent to the beam modulating means for scanning said beam through a display raster within an expanding beam envelope; and optical path folding means comprising spaced apart reflecting elements mounted rearwardly of and adjacent to said screen means and positioned to establish a path for the expanding beam envelope that traverses behind said screen means in at least two path segments, the final path segment directing the beam against said projection screen means with substantially varying angles and throw distances within the envelope. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A compact system for producing a high contrast large area visual display from a modulated laser beam comprising:
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scanning means for scanning the modulated laser beam through a display raster; optical path folding means disposed in the path of the scanning beam for providing a relatively long optical path for the beam within a confined volume; and areal display means adjacent the confined volume and substantially coextensive therewith for projecting the image defined by the display raster, the display means being disposed in the path of the focused beam adjacent the optical path folding means, said display including optical gain means. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A system for providing an areal color display, with respect to a viewing volume, of video signal information comprising:
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laser means providing a single small diameter beam containing at least two superposed collinear wavelength components of visible light; beam modulator means disposed in the path of the laser beam; excitation means coupled to the modulator means and responsive to the video signal for modulating the intensity of each of the wavelength components with in excess of 50% transmission efficiency while providing a single transmitted beam of small diameter having collinear modulated wavelength components; scanning means disposed in the path of the single transmitted beam for repetitively scanning the small diameter beam to provide a two-dimensional raster within a diverging beam envelope; areal optical display means in facing relation to the viewing volume and disposed to intersect the diverging beam envelope; and means optically coupled to said display means for redirecting impinging light energy from the scanning beam toward the viewing volume. - View Dependent Claims (26)
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27. The method of generating a large area color television display on a flat display surface comprising the steps of:
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generating a single laser beam containing wavelength components at three different frequencies; concurrently modulating the different wavelengths of the beam while maintaining different wavelength components in a single beam; scanning the modulated beam through a television raster within a beam envelope; expanding the beam envelope by multiple reflection of the beam within an enclosed volume adjacent the flat display surface; directing the beam against the flat display surface at an angle such that the beam impinges with substantial nonorthogonality relative to the display surface; and redirecting the incident beam energy at the display surface into a predetermined far field radiation pattern. - View Dependent Claims (28, 29, 30, 31)
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Specification