Liquid crystal display system with internally reflecting waveguide for backlighting and non-Lambertian diffusing

Claim 3

The apparatus of claim 1, further comprising a nonimaging optic between said illumination source and said incident surface, said nonimaging optic being optically connected to said illumination source and said first collimating waveguide.

Claim 4

The apparatus of claim 1, wherein said diffuser includes a light shaping holographic surface diffuser having at least one diffuser characteristic selected from the group consisting of directional and off-axis.

Claim 5

A backlight comprising: a collimating waveguide having a light input end, a top surface, a bottom surface, and opposing sides; said bottom surface converging toward said top surface in a direction along said backlight away from said light input end; said bottom surface comprising a plurality of straight facets having a density ρ distributed along said bottom surface in a direction along said backlight away from said light input end and extending at least part way between said opposing sides; each said straight facet having a straight facet bottom surface which converges toward said top surface in a direction along said backlight away from said light input end at an angle γ less than approximately 5°; each said straight facet bottom surface of each said straight facet being parallel to each said straight facet bottom surface of each other said straight facet; said collimating waveguide reflecting light rays entering said light input end in accordance with total internal reflection and entering with an angle greater than said total internal reflection critical angle; said facets causing light rays entering said light input end and having an angle near said total internal reflection critical angle to exit said top surface at an angle nearly tangential to said top surface.

Claim 6

A backlight comprising: a collimating waveguide having a light input end, a top surface, a bottom surface, and opposing sides; said bottom surface converging toward said top surface in a direction along said backlight away from said light input end; said bottom surface comprising a plurality of straight facets having a density ρ distributed along said bottom surface in a direction along said backlight away from said light input end and extending at least part way between said opposing sides; each said straight facet having a straight facet bottom surface which converges toward said top surface in a direction along said backlight away from said light input end at an angle γ less than approximately 5°; each said straight facet bottom surface of each said straight facet being parallel to each said straight facet bottom surface of each other said straight facet; said collimating waveguide reflecting light rays entering said light input end in accordance with total internal reflection and entering with an angle greater than said total internal reflection critical angle; said facets causing light rays entering said light input end and having an angle near said total internal reflection critical angle to exit said top surface at an angle nearly tangential to said top surface.

Claim 7

The backlight of claim 4, wherein said facets cause light rays entering said light input end and having an angle near said total internal reflection critical angle to exit said top surface at an angle of approximately 2γ.

Claim 8

The backlight of claim 4, wherein each said straight facet bottom surface is reflective to prevent light from leaking from each said straight facet bottom surface.

Claim 9

The backlight of claim 4, wherein each said straight facet bottom surface is metalized to prevent light from leaking from each said straight facet bottom surface.

Claim 10

The backlight of claim 4, wherein light leaks from each said straight facet bottom surface and from said top surface.

Claim 11

The backlight of claim 4, wherein each said straight facet extends between said opposing sides.

Claim 12

The backlight of claim 4, wherein said density ρ of said straight facets varies as a function of a distance from said light input end.

Claim 13

The backlight of claim 10, wherein said density ρ of said straight facets is such that an intensity of emitted light is uniform across a length of said backlight.

Claim 14

The backlight of claim 10, wherein each said straight facet bottom surface is metalized to prevent light from leaking from each said straight facet bottom surface.

Claim 15

The backlight of claim 4, further comprising a diffuser optically coupled to said top surface for homogenizing light exiting said top surface.

Claim 16

The backlight of claim 13, further comprising a non-Lambertian second diffuser optically coupled to said light input end for reducing reflection from said light input end.

Claim 17

The backlight of claim 4, further comprising a non-Lambertian diffuser optically coupled to said light input end for reducing reflection from said light input end.

Claim 18

The backlight of claim 4, further comprising a liquid crystal display optically coupled to said collimating waveguide.

Claim 19

The backlight of claim 16, further comprising a non-Lambertian diffuser optically coupled to said liquid crystal display for directing light from said liquid crystal display.

Claim 20

The backlight of claim 17, further comprising a second diffuser optically coupled to said top surface for homogenizing light exiting from said top surface.

Claim 21

The backlight of claim 18, further comprising a non-Lambertian third diffuser optically coupled to said light input end for reducing reflection from said light input end.

Claim 22

The backlight of claim 4, further comprising a spatial light modulator optically coupled to said collimating waveguide.

Claim 23

The backlight of claim 4, further comprising a light source optically coupled to said light input end.

Claim 24

The backlight of claim 21, further comprising a reflector optically coupled to said light source and optically coupled to said light input end of said collimating waveguide, said reflector at least partially surrounding said light source and reflecting light from said light source to said light input end by direct reflection, wherein light from said reflector is directly incident upon said light input end.

Claim 25

The backlight of claim 4, further comprising a second collimating waveguide optically coupled to said collimating waveguide, said second collimating waveguide including an upper surface and a second plurality of facets for redirecting light exiting said top surface through and out said upper surface at an angle substantially greater than 2γ and approximately normal to said top surface.

Claim 26

A backlight comprising: a collimating waveguide having a light input end, a top surface, a bottom surface, and opposing sides; said bottom surfaces converging toward said top surface in a direction along said backlight away from said light input end; said bottom surface comprising a plurality of straight facets having a density ρ distributed along said bottom surface in a direction along said backlight away from said light input end and extending at least part way between said opposing sides; each said straight facet having a straight facet bottom surface which converges toward said top surface in a direction along said backlight away from said light input end at an angle less than approximately 5°; each said straight facet bottom surface of each said straight facet being parallel to each said straight facet bottom surface of each other said straight facet; said collimating waveguide reflecting light rays entering said light input end in accordance with total internal reflection and at an angle greater than a total internal reflection critical angle; said facets causing light entering said light input end and having an angle near said total internal reflection critical angle to exit said top surface at an angle nearly tangential to said top surface and of approximately 2γ; a second collimating waveguide optically coupled to said collimating waveguide, said second collimating waveguide including an upper surface and a second plurality of facets for redirecting light exiting said top surface through and out said upper surface at an angle substantially greater than 2γ and approximately normal to said top surface; a non-Lambertian diffuser optically coupled to said second collimating waveguide for directing light exiting said second collimating waveguide.

Claim 27

A backlight comprising: a collimating waveguide having a light input end, a top surface, a bottom surface, and opposing sides; said bottom surfaces converging toward said top surface in a direction along said backlight away from said light input end; said bottom surface comprising a plurality of straight facets having a density ρ distributed along said bottom surface in a direction along said backlight away from said light input end and extending at least part way between said opposing sides; each said straight facet having a straight facet bottom surface which converges toward said top surface in a direction along said backlight away from said light input end at an angle less than approximately 5°; each said straight facet bottom surface of each said straight facet being parallel to each said straight facet bottom surface of each other said straight facet; said collimating waveguide reflecting light rays entering said light input end in accordance with total internal reflection and at an angle greater than a total internal reflection critical angle; said facets causing light entering said light input end and having an angle near said total internal reflection critical angle to exit said top surface at an angle nearly tangential to said top surface and of approximately 2γ; a second collimating waveguide optically coupled to said collimating waveguide, said second collimating waveguide including an upper surface and a second plurality of facets for redirecting light exiting said top surface through and out said upper surface at an angle substantially greater than 2γ and approximately normal to said top surface; a non-Lambertian diffuser optically coupled to said second collimating waveguide for directing light exiting said second collimating waveguide.

Claim 28

The backlight of claim 24, wherein said non-Lambertian diffuser provides a controllable output angle determined by surface features replicated in said non-Lambertian diffuser from speckle recorded in a photosensitive medium which determine angular output characteristics of said non-Lambertian diffuser.

Claim 29

The backlight of claim 24, wherein said second collimating waveguide is integral with said non-Lambertian diffuser.

Claim 30

The backlight of claim 25, wherein γ is in the range 0.5°-2.0°.

Claim 31

A backlight comprising: a collimating waveguide having a light input end, a top surface, a bottom surface, and opposing sides; said bottom surfaces converging toward said top surface in a direction along said backlight away from said light input end; said bottom surface comprising a plurality of straight facets distributed along said bottom surface in a direction along said backlight away from said light input end and extending at least part way between said opposing sides; each said straight facet having a straight facet bottom surface arranged substantially parallel to said bottom surface which converges toward said top surface in a direction along said backlight away from said light input end at an angle less than approximately 5°; and wherein said straight facet bottom surfaces cause light rays entering said light input end and having an angle near said total internal reflection critical angle to exit said top surface at an angle nearly tangential to said top surface.

Claim 32

A backlight comprising: a collimating waveguide having a light input end, a top surface, a bottom surface, and opposing sides; said bottom surfaces converging toward said top surface in a direction along said backlight away from said light input end; said bottom surface comprising a plurality of straight facets distributed along said bottom surface in a direction along said backlight away from said light input end and extending at least part way between said opposing sides; each said straight facet having a straight facet bottom surface arranged substantially parallel to said bottom surface which converges toward said top surface in a direction along said backlight away from said light input end at an angle less than approximately 5°; and wherein said straight facet bottom surfaces cause light rays entering said light input end and having an angle near said total internal reflection critical angle to exit said top surface at an angle nearly tangential to said top surface.

Claim 33

The backlight of claim 28, wherein said bottom surface converges toward said top surface at an angle between 0.5° to 2.0°.

Claim 34

The waveguide of claim 28 wherein said collimating waveguide reflects light rays entering said light input end in accordance with total internal reflection and at an angle greater than a total internal reflection critical angle.

Claim 35

The waveguide of claim 28 wherein said straight facet bottom surfaces cause light rays entering said light input end and having an angle near said total internal reflection critical angle to exit said top surface at an angle to said top surface and of approximately 2γ.

Claim 36

The waveguide of claim 28, wherein the facets have an density distribution along said bottom surface that varies as a function of a direction along said backlight away from said light input end.

Claim 37

The waveguide of claim 28, wherein each said straight facet bottom surface of each said straight facet is parallel to each said straight facet bottom surface of each other said straight facet.

Claim 38

The backlight of claim 28, wherein said facets cause light rays entering said light input end and having an angle near said total internal reflection critical angle to exit said top surface at an angle of approximately 2γ.

Claim 39

The backlight of claim 28, wherein each said straight facet bottom surface is reflective to prevent light from leaking from each said straight facet bottom surface.

Claim 40

The backlight of claim 28, wherein each said straight facet bottom surface is metalized to prevent light from leaking from each said straight facet bottom surface.

Claim 41

The backlight of claim 28, wherein light leaks from each said straight facet bottom surface and from said top surface.

Claim 42

The backlight of claim 28, wherein each said straight facet extends between said opposing sides.

Claim 43

The backlight of claim 28, wherein said density ρ of said straight facets varies as a function of a distance from said light input end.

Claim 44

The backlight of claim 39, said density ρ of said straight facets is such that an intensity of emitted light is uniform across a length of said backlight.

Claim 45

The backlight of claim 39, wherein each said straight facet bottom surface is metalized to prevent light from leaking from each said straight facet bottom surface.

Claim 46

The backlight of claim 28, further comprising a diffuser optically coupled to said top surface for homogenizing light exiting said top surface.

Claim 47

The backlight of claim 42, further comprising a non-Lambertian second diffuser optically coupled to said light input end for reducing reflection from said light input end.

Claim 48

The backlight of claim 28, further comprising a non-Lambertian diffuser optically coupled to said light input end for reducing reflection from said light input end.

Claim 49

The backlight of claim 28, further comprising a liquid crystal display optically coupled to said collimating waveguide.

Claim 50

The backlight of claim 28, further comprising a non-Lambertian diffuser optically coupled to said liquid crystal display for directing light from said liquid crystal display.

Claim 51

The backlight of claim 46, further comprising a second diffuser optically coupled to said top surface for homogenizing light exiting from said top surface.

Claim 52

The backlight of claim 47, further comprising a non-Lambertian third diffuser optically coupled to said light input end for reducing reflection from said light input end.

Claim 53

The backlight of claim 28, further comprising a spatial light modulator optically coupled to said collimating waveguide.

Claim 54

The backlight of claim 28, further comprising a light source optically coupled to said light input end.

Claim 55

The backlight of claim 39, further comprising a reflector optically coupled to said light source and optically coupled to said light input end of said collimating waveguide, said reflector at least partially surrounding said light source and reflecting light from said light source to said light input end by direct reflection, wherein light from said reflector is directly incident upon said light input end.

Claim 56

A backlight comprising: a collimating waveguide having a light input end, a top surface, a bottom surface, and opposing sides, said bottom surface converging toward said top surface in a direction along said backlight away from said light input end, said bottom surface comprising a plurality of curved facets distributed along said bottom surface in a direction along said backlight away from said light input end and extending at least part way between said opposing sides, each said curved facet having a curved facet bottom surface, each said curved facet bottom surface being arranged to reflect a ray-bundle incident to said curved facet bottom surface, and wherein said ray-bundle comprises a plurality of light rays and wherein each of said light rays is reflected substantially normally to the top surface in a symmetrical distribution.

Claim 57

A backlight comprising: a collimating waveguide having a light input end, a top surface, a bottom surface, and opposing sides, said bottom surface converging toward said top surface in a direction along said backlight away from said light input end, said bottom surface comprising a plurality of curved facets distributed along said bottom surface in a direction along said backlight away from said light input end and extending at least part way between said opposing sides, each said curved facet having a curved facet bottom surface, each said curved facet bottom surface being arranged to reflect a ray-bundle incident to said curved facet bottom surface, and wherein said ray-bundle comprises a plurality of light rays and wherein each of said light rays is reflected substantially normally to the top surface in a symmetrical distribution.

Claim 58

The backlight of claim 52, wherein said plurality of curved facets are arranged in an array distributed on said bottom surface.

Claim 59

The backlight of claim 52, wherein said plurality of curved facets are arranged in a segmented array.

Claim 60

The backlight of claim 52, wherein said plurality of curved facets are arranged into segments, each said segment being arranged parallel to each other said segment.

Claim 61

The backlight of claim 52, wherein said plurality of curved facets are distributed with an increasing density ρ from said light input end.

Claim 62

The backlight of claim 52, wherein said density ρ of said straight facets is such that an intensity of emitted light is uniform across a length of said backlight.

Claim 63

The backlight of claim 27, wherein each of said plurality of curved facets are concave with respect to said top surface.

Claim 64

The backlight of claim 54, wherein said bottom surface converges towards said top surface at an angle less than about 5°.

Claim 65

The backlight of claim 54, wherein said bottom surface converges toward said top surface at an angle of about 0.50°-2.0°.

Claim 66

The backlight of claim 54, wherein said collimating waveguide further comprises a second light input end opposing said light input end, said bottom surface further comprising a plurality of second curved facets each opposing said plurality of curved facets and each having a second curved facet bottom surface, each said second curved facet being arranged to reflect a second ray-bundle incident to said second curved facet bottom surface, and wherein said second ray-bundle comprises a plurality of light rays and wherein each of said light rays are reflected substantially normally to the top surface and in a symmetrically distribution.

Claim 67

The backlight of claim 61, wherein each said second curved facet is concave with respect to said top surface.

Claim 68

The backlight of claim 61, wherein each said curved facet and each said second curved facet is concave with respect to said top surface.

Claim 69

The backlight of claim 61, wherein each said curved facet and each said second curved facet is arranged with scalloped edges, said scalloped edges collimating skew light rays.

Claim 70

The backlight of claim 62, wherein each said curved facet and each said second curved facet are arranged to preferentially direct a light flux substantially normal to said top surface.

Claim 71

The backlight of claim 65, wherein light flux enters said waveguide collimator from said light input end and said second light input end.

Claim 72

A backlight comprising: a collimating waveguide having a light input end, a top surface, a bottom surface, and opposing sides, said bottom surface converging toward said top surface in a direction along said backlight away from said light input end, said bottom surface comprising a plurality of curved facets having a density distributed along said bottom surface in a direction along said backlight away from said light input end and extending at least part way between said opposing sides, each said curved facet having a curved facet bottom surface, each said curved facet bottom surface being curved substantially in accordance with the equation: ##EQU33## where β is the angle of a highest inclination incident ray and w and G are dimensions of said curved facet; and said plurality of curved facets causing light entering said light input end and reflecting from said plurality of curved facets to reflect from each said curved facet bottom surface symmetrically with respect to an axis normal to said top surface.

Claim 73

A backlight comprising: a collimating waveguide having a light input end, a top surface, a bottom surface, and opposing sides, said bottom surface converging toward said top surface in a direction along said backlight away from said light input end, said bottom surface comprising a plurality of curved facets having a density distributed along said bottom surface in a direction along said backlight away from said light input end and extending at least part way between said opposing sides, each said curved facet having a curved facet bottom surface, each said curved facet bottom surface being curved substantially in accordance with the equation: ##EQU33## where β is the angle of a highest inclination incident ray and w and G are dimensions of said curved facet; and said plurality of curved facets causing light entering said light input end and reflecting from said plurality of curved facets to reflect from each said curved facet bottom surface symmetrically with respect to an axis normal to said top surface.