Light distribution apparatus and methods for illuminating optical systems
First Claim
1. A heads-up display for displaying images, said heads-up display comprising:
- a spatial light modulator comprising a plurality of pixels selectively adjustable for creating a spatial pattern;
a light source for illuminating an area on said spatial light modulator;
a diffuser disposed in an optical path between said light source and said spatial light modulator such that a portion of said diffuser receives light from said light source, said light source disposed in an arrangement that provides increasing illuminance along a transverse direction of said diffuser, said diffuser comprising a plurality of light spreading features configured to disperse light from said light source into increasingly larger projected solid angles for locations along said transverse direction of said diffuser; and
imaging optics disposed to receive said light incident on said spatial light modulator for forming an image of said spatial pattern created by said spatial light modulator.
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Accused Products
Abstract
Various embodiments involving structures and methods for illumination can be employed, for example, in projectors, head-mounted displays, helmet-mounted displays, back projection TVs, flat panel displays as well as other optical systems. Certain embodiments may include prism elements for illuminating, for example, a spatial light modulator. Light may be coupled to the prism in some cases using fiber optics or lightpipes. The optical system may also include a diffuser having scatter features arranged to scatter light appropriately to produce a desired luminance profile. Other embodiments are possible as well.
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Citations
68 Claims
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1. A heads-up display for displaying images, said heads-up display comprising:
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a spatial light modulator comprising a plurality of pixels selectively adjustable for creating a spatial pattern;
a light source for illuminating an area on said spatial light modulator;
a diffuser disposed in an optical path between said light source and said spatial light modulator such that a portion of said diffuser receives light from said light source, said light source disposed in an arrangement that provides increasing illuminance along a transverse direction of said diffuser, said diffuser comprising a plurality of light spreading features configured to disperse light from said light source into increasingly larger projected solid angles for locations along said transverse direction of said diffuser; and
imaging optics disposed to receive said light incident on said spatial light modulator for forming an image of said spatial pattern created by said spatial light modulator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An illumination engine for projecting images onto a screen comprising:
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a spatial light modulator for forming spatial patterns;
projection optics for projecting spatial patterns formed by said spatial light modulator onto a screen;
a diffuser having a lateral spatial extent in a transverse direction and an optical axis therethrough, said diffuser comprising a plurality of scatter features; and
an off-axis light source for illuminating a spatial region on said diffuser and a corresponding section of said spatial light modulator, wherein said off-axis light source is disposed with respect to said diffuser to produce varying illuminance along said transverse direction, said optical scattering features in said diffuser dispersing light into an increasingly large range of angles for locations along said transverse direction such that said luminance across said spatial light modulator is substantially constant. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. An optical image forming system comprising:
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a modulator array comprising a plurality of modulators that can be modulated to produce spatial patterns;
projection optics disposed in an optical path from said modulator array;
a light source outputting light for illuminating said spatial light modulator;
a light distribution system for distributing said light across said spatial light modulator, said light distribution system having an output having a lateral spatial extent and a numerical aperture that varies across said lateral spatial extent, wherein said light source together with said light distribution system provides increasing illuminance across said lateral spatial extent of said output. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39)
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- 40. An apparatus for providing a non-uniform illuminance, said apparatus comprising a plurality of non-imaging optical elements arranged over an area having a lateral spatial extent, said non-imaging optical elements having input and output apertures and input and output numerical apertures, said input apertures and said output numerical apertures increasing across said lateral spatial extent so as to provide substantially constant luminance across said lateral spatial extent.
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44. An optical diffuser for receiving a light beam that produces an illuminance distribution that increases in a transverse direction across said diffuser, said optical diffuser comprising:
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a body extending laterally in said transverse direction, said body having an outer surface and a volume; and
light dispersing features arranged across said lateral spatial extent of said diffuser to diffuse light incident thereon, said light incident on a given location on said diffuser being distributed by said light dispersing features into a range of angles that is determined by said light dispersing features, said range of angles corresponding to a projected solid angle, wherein said light dispersing features are arranged across said diffuser such that said projected solid angle increases for respective locations along a transverse direction across a substantial portion of said diffuser. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56)
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57. A method of displaying an image with a heads-up display, said method comprising:
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producing increasing illuminance across a diffuser;
scattering light incident on different locations across said diffuser into increasing large projected solid angles so as to produce a substantially constant luminance;
directing said scattered light having substantially constant luminance to said spatial light modulator;
forming a pattern with said spatial light modulator;
propagating light from said spatial light modulator to imaging optics; and
forming an image of said pattern formed by said spatial light modulator with said imaging optics. - View Dependent Claims (58, 59)
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60. A method of projecting an image on a rear projection TV, said method comprising:
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producing increasing illuminance at an input of an light distribution optics having a lateral spatial extent and an output with increasing numerical aperture across said lateral spatial extent;
outputting light from said light distribution optics having increasing numerical aperture across said lateral spatial extent into increasingly large projected solid angles across said lateral spatial extent so as to reduce variation in luminance;
directing said light with reduced variation in luminance to said spatial light modulator;
forming a pattern with said spatial light modulator based on video or computer signals;
propagating light from said spatial light modulator to imaging optics; and
forming an image of said pattern formed by said spatial light modulator with said imaging optics onto said screen of said rear projection TV. - View Dependent Claims (61, 65, 66, 67)
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62. A method of forming an image for a display, said method comprising:
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modulating an array of optical modulators to produce a spatial pattern;
illuminating an area on said array of optical modulators with a beam of light having increasing illuminance and substantially constant luminance across a cross- section of the beam to provide increasing illuminance and substantially constant luminance across said area on said array of modulator illuminated by said beam; and
propagating said light from said array of optical modulators into optics for forming said image. - View Dependent Claims (63)
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64. A color projection system for projecting color images, said color projection system comprising:
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a spatial light modulator comprising a plurality of pixels for forming patterns;
projection optics disposed with respect to said spatial light modulator for forming an image of said pattern formed by said spatial light modulator, said projection optics having an F-number that varies across a lateral dimension;
illumination optics having a numerical aperture that varies across said lateral direction, said variation in said numerical aperture of said illumination optics substantially matching said F-number of said projection optics for illuminating said spatial light modulator; and
a source of light coupling light to said illumination optics, wherein said source of light and said illumination optics together provide a variation in illuminance at said spatial light modulator such that said luminance is substantially constant at said spatial light modulator.
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68. A method of projecting an image onto a screen, said method comprising:
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forming a pattern with an array of modulators;
illuminating an area of said array of modulators with illumination having substantially constant luminance across said area;
imaging said area with imaging optics having a pupil and an F-number that varies across a dimension of said array of modulators, wherein said illumination at said array of modulators has (i) increasing divergence across said area so as to substantially fill said pupil with said variation in F-number without substantially overfilling and (ii) increasing illuminance across said area to provide substantially constant luminance.
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Specification