Light distribution apparatus and methods for illuminating optical systems
First Claim
Patent Images
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 a first 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 light from said spatial light modulator for forming an image of said spatial pattern created by said spatial light modulator, said spatial light modulator and said imaging optics defining a second optical path therebetween,wherein said diffuser is outside said second optical path between said spatial light modulator and said imaging optics.
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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
51 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 a first 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 light from said spatial light modulator for forming an image of said spatial pattern created by said spatial light modulator, said spatial light modulator and said imaging optics defining a second optical path therebetween, wherein said diffuser is outside said second optical path between said spatial light modulator and said imaging optics. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An illumination engine for projecting images onto a screen, the illumination engine 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, said projection optics and said spatial light modulator defining an optical path therebetween; a diffuser having a lateral spatial extent in a transverse direction and an optical axis therethrough, said diffuser comprising a plurality of scatter features, said diffuser outside said optical path between said projection optics and said spatial light modulator; 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 larger range of angles for locations along said transverse direction such that luminance across said spatial light modulator is substantially constant. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. An illumination engine comprising:
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a spatial light modulator at one end of an optical path; projection optics configured to project spatial patterns formed by said spatial light modulator, said projection optics at another end of said optical path; a light source configured to generate a light beam, an optical diffuser outside said optical path between said spatial light modulator and said projection optics, said diffuser configured to receive said light beam, said light beam producing an illuminance distribution that increases in a transverse direction across said diffuser, said diffuser comprising; a body extending laterally in said transverse direction to define a lateral spatial extent, 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 (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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47. 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 increasingly larger projected solid angles so as to produce a substantially constant luminance; directing said scattered light having substantially constant luminance to a spatial light modulator; forming a pattern with said spatial light modulator; propagating light from said spatial light modulator to imaging optics along an optical path that excludes said diffuser; and forming an image of said pattern formed by said spatial light modulator with said imaging optics. - View Dependent Claims (48, 49, 50, 51)
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Specification