Thin illumination system

Abstract

The present invention introduces a new class of thin doubly collimating light distributing engines for use in a variety of general lighting applications. Output illumination from these slim-profile illumination systems whether square, rectangular or circular in physical aperture shape is directional, square, rectangular or circular in beam cross-section, and spatially uniform and sharply cutoff outside the system's adjustable far-field angular cone. Some embodiments provided include thin light distributing engines which provide input light collimated in one meridian and a light distributing element that maintains input collimation while collimating output light in the un-collimated orthogonal meridian, in such a manner that the system's far-field output light is collimated in both its orthogonal output meridians. The present invention can also include optical films that process the engine's doubly collimated output illumination so as to increase its angular extent one or both output meridians without changing beam shape or uniformity.

What is claimed is: 
     
         1 . An illuminating system, comprising:
 a light emitter comprising at least one light source emitting light along a source optical axis and a first light distributing optic having a first input aperture disposed just beyond said at least one light source and having a first output aperture disposed beyond said first input aperture, said first light distributing optic collecting substantially all light emitted from said at least one light source and directing said emitted light substantially along a first optical axis orthogonal to said first output aperture such that light output from said first light distributing optic is collimated into a narrow first angular extent in a first meridinal plane parallel to said first optical axis and also into a wider second angular extent in a second meridinal plane orthogonal to said first meridinal plane, said output light in both said first and second meridinal planes distributed substantially evenly over the first output aperture,   a second light distributing optic comprising one or more of light guide plates, thin optical films with integral optical light redirecting structure, and specularly-reflecting mirror planes, said second light distributing optic having a second input aperture disposed just beyond said first output aperture of said first light distributing optic so as to receive substantially all of the light output from said first output aperture of said first light distributing optic, said second light distributing optic directing light substantially along a directional axis and converting said first angular extent of the light into a first output angular extent in a first output meridinal plane parallel to the directional axis, said second light distributing optic further collimating the light into a second output angular extent in a second output meridinal plane orthogonal to said first output meridinal plane, said second light distributing optic processing the light such that the light exits substantially evenly from a second output aperture of the second light distributing optic, the second output aperture having a second output aperture area substantially larger than the area of the second input aperture so that the light output in total has a characteristically lower aperture brightness in direct view than does said at least one light source despite the light output by the said at least one light source having a wider angular distribution.   
     
     
         2 . The illumination system of  claim 1  where the first light distributing optic comprises a four-sided etendue preserving angle transforming reflector having said first input aperture and further comprises a light guiding pipe having said first output aperture, said light guiding pipe disposed just beyond and receiving substantially all of the light from an output aperture of said four-sided etendue preserving angle transforming reflector, said light guiding pipe having said first optical axis oriented orthogonal to said source optical axis, said light guiding pipe comprising one or more of a light guide bar having rectangular cross-section, a tapered light guide bar having rectangular cross-section with a knife edge at one end, specularly reflective optical films, light extraction films, and optical films with integral light redirecting structure. 
     
     
         3 . The illumination system of  claim 1  where the first light distributing optic consists of a four-sided etendue preserving angle transformer having said first input aperture and said first output aperture and having two of its four sidewalls collimating the light from the light source into said narrow first angular extent and the other two of its four sidewalls collimating the light from the light source into said wide second angular extent. 
     
     
         4 . An illuminating system, comprising:
 a light emitting optic comprising at least one individual light emitting source, said light emitting optic emitting a substantial portion of its output light from a generalized cylindrical output aperture, said generalized cylindrical output aperture having an effective circumferential thickness of D2 and an effective length of D1, with D1 being at least 2 times D2.   a substrate circuit and heat extraction structure with electrical interconnection for said at least one individual light emitting source to a supply of electrical power for said at least one light emitting source,   a light distributing optic comprising a light guide plate, having a generalized cylindrical input aperture, having circular or polygonal shaped output aperture in a plane orthogonal to said generalized cylindrical input aperture, whose optical axis passes through a center point A of said output aperture and is orthogonal to a plane defined by said output aperture, said light distributing optic so disposed such that its said generalized cylindrical input aperture is located just beyond said generalized cylindrical output aperture area of said light emitting optic receiving substantially all of the light from said light emitting optic, said light distributing optic directing the received light within said light distributing optic substantially along optical paths orthogonal to said optical axis; and   a light redirecting optic comprising one or more of a thin optical film with integral optical light redirecting structures, an optically transparent dielectric film of lower refractive index than said light guide plate, a specularly reflecting mirror plane, and one or more light spreading diffuser films, said one or more thin optical film with integral optical light redirecting structures having a circular or polygonal shaped receiving aperture, a circular or polygonal shaped transmitting aperture, and an output optical axis being orthogonal to said circular or polygonal shaped transmitting aperture, with said circular or polygonal shaped receiving aperture and said circular or polygonal shaped transmitting aperture being substantially parallel to each other, said light redirecting optic disposed adjacent to said light distributing optic, said light redirecting optic receiving and redirecting said light output from said light distributing optic substantially along a directional axis parallel to or at an angle to said output optical axis, said light redirecting optic processing said light output such that it exits said circular or polygonal shaped transmitting aperture substantially evenly having a collimated angular extent in all output meridinal planes parallel to said directional axis, the effective brightness of said circular or polygonal shaped transmitting aperture in direct view being substantially less than an effective brightness of said light emitting source despite said light emitting source having a relatively wider angular distribution.   
     
     
         5 . The illumination system as defined in  claim 4  wherein the light guide of the light distributing optic has a physical thickness D 2  an outer diameter D, and center point P, said light guide plate being made of an optically transparent dielectric material containing one of a circular hole or a conical surface feature disposed at its center, said circular hole or said conical surface feature being of diameter D 0 , D 0  being at least D/10, said circular shaped light guide plate having a fixed length cross-sectional area from center to edge that has been revolved 360-degrees about said center point P and that tapers with an angle α from thickness D 2  to thickness K, thickness K being at least D 2 /10, taper angle α being substantially Tan −1  [D 2 /(D/2)]. 
     
     
         6 . The illumination system as defined in  claim 4  wherein the light distributing optic comprises a square or rectangular shaped light guide plate having physical thickness D 2 , a mirror-like top surface, a mirror-like bottom surface, outer edge dimensions D X  and D Y , corner points A, B, C and D, and center point P, said light guide plate being made of an optically transparent dielectric material containing one of a circular hole or a conical surface feature disposed at its center, said circular hole or said conical surface feature being of diameter D 0 , D 0  at least D/10, said circular shaped light guide plate having a four sided tapered cross-sectional area of variable length D′, a first side being the line of height D2+K with top and bottom end points T1 and T2, a second side being the knife edge line of height K with top and bottom end points T3 and T4, said first side and said second side being substantially parallel, a third side of variable line length D′ having left and right end points T5 and T6, said left end point T5 of said third side connected to said bottom end point T1 of said first side, said right end point T6 connected to said bottom end point T3 of said second side, and a fourth side being a string of one or more connected line segments with left and right end points T7 and T8 such that said left end point T7 of said string of one or more line segments connects to said top end point T2 of said first side and such that said right end point T8 of said string of one or more line segments connects to top end point T4 of said second side, the four sided tapered cross-sectional area revolved 360-degrees about said center point P with the constraint that said variable line length D′ is increased or decreased such that end points T3 and T6 remain coincident with bounding edges A-B, B-C, C-D and A-D, with the average taper angle of any line segment in said string of one or more line segments a being substantially Tan −1 [D 2 /(D′/2)] where said variable length D′ ranges between D x /2, D y /2 and [(D x /2) 2 +(D y /2) 2 ] 1/2 . 
     
     
         7 . The illumination system as defined in  claim 4  wherein the light redirecting optic includes a circular cut, square cut or rectangular cut light redirecting film of thickness T and from a circle of outside diameter D made of optically transparent dielectric material containing a center point B, a plane top surface and a plane bottom surface, said plane top surface being a featureless mirror plane and said plane bottom surface being parallel to said plane top surface while containing a sequential series of circular grooves having inner and outer groove wall surfaces formed radially outwards from said center point B by sweeping a continuous series of identically tilted line segment pairs about an optical axis orthogonal to said top and bottom plane surfaces at said center point B, each said identically tilted line segment pair comprising an inner and an outer tilted line segment joined together at an apex point of height H above the plane of said bottom surface, said inner tilted line segment making an angle (90−β L ) with the plane of said plane bottom surface, said outer tilted line segment making an angle (90−β R ) with the plane of said plane bottom surface, such that the total included angle between said inner and said outer tilted line segments in each said identically tilted line segment pair is (β L +β R ) and such that the projected lengths of each said inner and outer tilted line segments on said plane bottom plane is (H)Tan(β L ) and (H)Tan(β R ) respectively, with the number of identically tilted line segment pairs disposed radially between said center point N and outside diameter D being (D/2)/[(H)Tan(β L )+(H)Tan(β R )], said outer circular groove wall surfaces receiving substantially all the light incident on said light redirecting optic. 
     
     
         8 . The illumination system as defined in  claim 7  wherein said light redirecting film is made 100 to 300 microns thick from an optically transparent polymeric material, with said inner tilted line segment having tilt angles β L  between 1 and 10 degrees and said inner tilted line segment having tilt angles β R  between 31 and 39 degrees, said plane top surface and said bottom surface each being treated with single or multilayer antireflection coatings, said bottom plane of said light redirecting film disposed just beyond said mirror-like top surface of said tapered light guide plate, and said plane or tapered specularly reflecting mirror plane disposed just below said mirror-like bottom surface of said tapered light guide plate. 
     
     
         9 . The illumination system as defined in  claim 7  wherein said light redirecting film is made 100 to 300 microns thick from an optically transparent polymeric material, with said inner tilted line segment having tilt angles β L  between 32 and 40 degrees and said inner tilted line segment having tilt angles β R  between 49 and 59 degrees, said plane top surface being coated with or laminated to a dielectric thin film layer having a refractive index between 1.38 and 1.43, and said bottom surface coated with a highly reflective metallic film taken from the group of protected and enhanced aluminum, protected aluminum, protected and enhanced silver, and protected silver, said top plane of said light redirecting film disposed just beyond and optically coupled to said mirror-like bottom surface of said tapered light guide plate. 
     
     
         10 . The illuminating system as defined in  claim 4  wherein the one or more light spreading diffuser films comprise one or more lenticular lens sheets disposed beyond said light distributing optic and said light redirecting optic, the lenticular lens sheets having spherical or parabolic shaped lenticules facing towards said light redirecting optic. 
     
     
         11 . The illuminating system as defined in  claim 4  wherein said light emitting optic comprises an array of individual light emitting sources, a cylindrically shaped reflector, a said substrate circuit and heat extraction mechanism comprising a cylindrically shaped substrate for said array of individual light emitting sources containing one or more from a group of cylindrically disposed printed electronic circuit, substantially cylindrically shaped metallic heat extraction mechanism, dielectric insulation coating mechanism disposed between said cylindrically shaped printed electronic circuit and said substantially cylindrically shaped metallic heat extraction mechanism, and an electrical connection to said supply of electrical power for said individual light emitting sources, said array of individual light emitting sources disposed in a 360 degree ring upon and electrically attached to said cylindrically shaped printed electronic circuit, said the input aperture of said cylindrically shaped reflector disposed just beyond the emitting apertures of said array of individual light emitting sources, receiving substantially all the emitted light from said array of individual light emitting sources, the cylindrical output aperture of said cylindrically shaped reflector emitting light of narrower angular extent in the set of meridinal planes orthogonal to the plane of said circular or polygonal shaped output aperture of said light distributing optic, the cylindrical output aperture of said cylindrically shaped reflector emitting light of substantially no change to the angular extent of light in the set of meridinal planes parallel to the plane of said circular or polygonal shaped output aperture of said light distributing optic. 
     
     
         12 . The illuminating system as defined in  claim 4  wherein said light emitting optic comprises an array of one or more individual light emitting sources, a conically shaped reflector surface, a said substrate circuit and heat extraction mechanism comprising a substrate for said array of one or more individual light emitting sources containing one or more from a group of planar printed electronic circuit, metallic heat extraction mechanism, dielectric insulation coating mechanism disposed between said planar printed electronic circuit and said metallic heat extraction mechanism, and an electrical connection to said supply of electrical power for said array of one or more light emitting sources, said array of one or more light emitting sources disposed about said center point A of said output aperture of said light distribution optic and closely arranged with respect to one another about said center point A and electrically attached to said printed electronic circuit, said conically shaped reflector surface disposed directly above said array of one or more light emitting sources, with apex point C of said conically shaped reflector surface disposed beyond the emitting apertures of said array of one or more light emitting sources such that said conically shaped reflector surface receives a significant fraction of the substantially hemispherical light distribution emitted from said array of one or more light emitting sources, said conically shaped reflector surface redirecting said significant fraction of the substantially hemispherical light distribution into said generalized cylindrical input aperture of said light distributing optic.