DE112015003118T5 - Waveguide with unidirectional illumination - Google Patents

Abstract

A luminaire comprises an optical waveguide having a first surface and a second surface opposite to the first surface, and a light source associated with the optical waveguide. At least about 80% of the light generated by the light source is directed by the waveguide into an illumination distribution emitted from the first surface of the optical waveguide.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. Pat. Patent Application No. 14 / 472,078, filed August 28, 2014, entitled "Waveguide Having Unidirectional Illuminance" (Cree Serial No. P2289US1).

The present application claims the priority of U.S. Pat. Provisional Patent Application No. 61 / 922,017, filed December 30, 2013, entitled "Optical Waveguide Bodies and Luminaires Utilizing Same" (Cree Serial No. P2143USO) and U.S. Pat. Provisional Patent Application No. 62 / 020,866, filed July 3, 2014, entitled "Luminaires Utilizing Edge Coupling" (Cree Serial No. P2289USO). The present application further includes a continuation-in-part of U.S. Pat. Patent Application No. 13 / 839,949, filed Mar. 15, 2013, entitled "Optical Waveguide and Lamp Including Same" (Cree Serial No. P1961US1), and further includes a continuation-in-part of U.S. Pat. Patent Application No. 13 / 840,563, filed March 15, 2013, entitled "Optical Waveguide and Luminaire Incorporating Same" (Cree Serial No. P2025US1), and further includes a continuation-in-part of U.S. Pat. Patent Application No. 13 / 938,877, filed July 10, 2013, entitled "Optical Waveguide and Luminaire Incorporating Same" (Cree Serial No. P2025US2), and further includes a continuation-in-part of U.S. Pat. Patent Application No. 14 / 101,086, filed December 9, 2013, entitled "Optical Waveguides and Luminaires Incorporating Same" (Cree Serial No. P2126US1), and further includes a continuation-in-part of U.S. Pat. Patent Application No. 14 / 101,132, filed December 9, 2013, entitled "Waveguide Bodies Including Redirection Features and Methods of Producing Same" (Cree Serial No. P2130US1), and further includes a continuation-in-part of U.S. Pat. Patent Application No. 14 / 101,147, filed December 9, 2013, entitled "Luminaires Using Waveguide Bodies and Optical Elements" (Cree Serial No. P2131US1), and further includes a continuation-in-part of U.S. Pat. Patent Application No. 14 / 101,129, filed December 9, 2013, entitled "Simplified Low Profile Modules With Light Guide For Pendant, Surface Mount, Wall Mount, and Stand Alone Luminaires" (Cree Serial No. P2141US1), and further includes a Continuation-In-Part of the US Patent Application No. 14 / 101,051, filed December 9, 2013, entitled "Optical Waveguide and Lamp Including Same" (Cree Serial No. P2151US1), and further includes a continuation-in-part of International Patent Application No. PCT / US14 / 13937, filed January 30, 2014, entitled "Optical Waveguide Bodies and Luminaires Utilizing Same" (Cree Serial No. P2143WO), and further includes a continuation-in-part of International Patent Application No. PCT / US14 / 13931, filed Jan. 30, 2014, entitled "Optical Waveguides and Luminaires Incorporating Same" (Cree Serial No. P2126WO), all of the assignee of the present application, the disclosures of which are incorporated herein by reference. This patent application incorporates by reference the co-pending U.S. Pat. Patent Application No. 14 / 472,064, entitled "Luminaire with Adjustable ective Luminous Intensity Pattern" (Cree Serial No. P2262US1) filed on August 28, 2014, and U.S. Pat. Patent Application No. 14 / 472,035, entitled "Luminaires Utilizing Edge Coupling" (Cree Serial No. P2346US1) filed on Aug. 28, 2014, both owned by the assignee of the present application.

The present application also claims priority to International Patent Application No. PCT / US14 / 13934, filed January 30, 2014, entitled "Optical Waveguide and Luminaire Incorporating Same" (Cree Serial No. P2025WO); International Patent Application No. PCT / US14 / 13931, filed January 30, 2014, entitled "Optical Waveguides and Luminaires Incorporating Same" (Cree Serial No. P2126WO); International Patent Application No. PCT / US14 / 13840, filed January 30, 2014, entitled "Simplified Low Profile Module with Light Guide for Pendant, Surface Mount, Wall Mount, and Stand Alone Luminaires" (Cree Serial No. P2141WO); International Patent Application No. PCT / US14 / 13891, filed January 30, 2014, entitled "Optical Waveguide and Lamp Including Same" (Cree Serial No. P2151WO); and International Patent Application No. PCT / US14 / 72860, filed December 30, 2014, entitled "Luminaires Utilizing Edge Coupling" (Cree Serial No. P2346WO); International Patent Application No. PCT / US ** / *****, entitled "Luminaire with Selectable Luminous Intensity Pattern" (Cree Serial No. P2262WO).

NOTICE ON RESEARCH AND DEVELOPMENT ACTIVITIES SUPPORTED BY THE GOVERNMENT

• Not applicable

SEQUENTIAL LISTING

• Not applicable

FIELD OF THE INVENTION

The subject of the application relates to lighting devices, and more particularly to a luminaire using optical waveguides for general lighting.

BACKGROUND OF THE INVENTION

An optical waveguide mixes and guides light emitted by one or more light sources, such as one or more light emitting diodes (LEDs). A typical optical waveguide comprises three main components: one or more coupling elements, one or more distribution elements and one or more extraction elements. The coupling component (s) directs light into the distribution element (s) and recycles the light so that it interacts with the subsequent components. The one or more distribution elements control how light passes through the waveguides and are independent of waveguide geometry and waveguide material. The extraction element (s) determine how light is removed by controlling where and in what direction the light exits the waveguide.

When designing a coupling element, the main considerations are as follows: maximizing the efficiency of light transfer from the source to the waveguide; Controlling the location of light injected into the waveguide; and controlling the angular distribution of the light in the waveguide. The coupling element of a waveguide may comprise one or more of a number of optical elements, including a "primary" source optic (such as the lens on an LED component package), one or more intermediate optical elements, one or more intermediate optical elements (such as a lens) or an array of lenses) disposed between the source and the coupling surface or surfaces of the waveguide, one or more reflective or diffusing surfaces surrounding the sources, and specific optical geometries formed in the waveguide coupling surfaces themselves. Proper design of the elements forming the coupling element can provide control over the spatial and angular spread of the light within the waveguide (and hence how the light interacts with the extraction elements), the coupling efficiency of light into the waveguide To maximize waveguides, and to improve the mixing of light from different sources within the waveguide (which is especially important as the color changes from the sources - either through the design or as a result of a normal bin-to-bin variation in the lighting components ). The elements of the waveguide coupling system may use reflection, diffraction, total reflection, and surface or volume scattering to control the distribution of the light injected into the waveguide.

In order to increase the coupling of the light from a light source into a waveguide, it is desirable to maximize the number of light rays emitted by the source (s) and which impinge directly on the waveguide coupling surface. Light rays that do not directly strike the waveguide from the source undergo one or more reflections or scattering events before they reach the waveguide coupling surface. Each such beam is thus exposed to absorption at each reflection or scattering event, resulting in loss of light and inefficiency. Further, each beam incident on the coupling surface has a part that is reflected (a Fresnel reflection) and a part that is transmitted into the waveguide. The percentage that is reflected is smallest when the beam hits the coupling surface at an angle of incidence relative to the surface normal close to zero (ie, approximately normal to the surface). The percentage that is reflected is greatest when the beam is incident at an angle relative to the surface normal to the coupling surface (i.e., approximately parallel to the surface). In order to increase the efficiency, the coupling of the light into the waveguide body minimizes the absorption of light in reflection or scattering events, as well as the Fresnel reflection at the coupling surface.

In a conventional coupling, a light source, which typically emits a Lambertian distribution of light, is positioned adjacent to the edge of a planar waveguide element. The amount of light incident directly on the coupling surface of the waveguide in this case is limited due to the wide angular distribution of the source and the relatively small fixed angle represented by the adjacent planar surface. In order to increase the amount of light directly incident on the coupling surface, a naked component such as the Cree ML series or MK series (manufactured and sold by Cree Inc. of Durham, NC, the assignee of the present application) may be used , A bare component is a light source that does not include a primary optic, lens, or discrete coupling optic formed on an LED chip. The flat emission surface of the LED chip can be close to the coupling surface of the waveguide are arranged. While this arrangement assists in ensuring that much of the emitted light is incident directly on the waveguide, overall system efficiency generally decreases because bare components are typically less efficient than primary lens components that allow light extraction from the component the overall efficiency is improved.

As described above, the use of higher efficiency LED elements having conventional (e.g., predominantly hemispherical or cubic) primary optical arrangements results in a limited amount of light being incident directly on the coupling surface of the waveguide. Such a light source (such light sources) is often placed in a reflective channel or cavity to reflect light onto the coupling surface, thereby increasing the amount of light from the source reaching the waveguide, but also the overall system efficiency is reduced as a result of the losses that occur in each reflection event. In some luminaires, the waveguide (may include the waveguides) may have coupling surfaces that are specifically shaped to maximize the amount of light received at the coupling surfaces. Alternatively, each LED may be positioned in a cylindrical coupling cavity within the waveguide, and a reflective cap having a cone shaped plug diverter may be disposed at the opposite end of the coupling cavity at the opposite end of the coupling cavity.

After light has been coupled into the waveguide, it must be routed to the extraction sites and conditioned. The simplest example is a fiber optic cable designed to carry light from one end of the cable to another with minimal loss in between. To achieve this, fiber optic cables are only gently curved and sharp bends in the waveguide are avoided. In accordance with well-known principles of total reflection, light propagating through a waveguide is reflected back into the waveguide from an outer surface thereof, provided that the incident light does not exceed a critical angle with respect to the surface. In particular, the light rays continue to propagate through the waveguide until such rays impinge on a refractive index transition surface at a certain angle less than an angle measured with respect to a line normal to the surface point at which the light rays are incident equivalently until the light rays exceed an angle measured with respect to a line tangent to the surface point where the light rays are incident) and the light rays escape.

For an extraction element to extract light from the waveguide, the light must first contact the feature comprising the element. By properly shaping the waveguide surfaces, one can control the flux of light across the extraction feature (s), thus affecting both the position from which the light is emitted and the angular distribution of the emitted light. In particular, the design of the coupling and distribution surfaces, in combination with the spacing (distribution), shape and other characteristics of the extraction features, provides control over the appearance of the waveguide (the illumination), the resulting angular distribution of the emitted light (brightness) and the optical efficiency of the system.

In the design of waveguide / extractor lighting systems, one important consideration is the purpose and / or positioning of the luminaire relative to the viewer and the illuminated surfaces. For example, in general lighting systems, such as a Troffer (ceiling) lighting, the light source or light is typically mounted on or near the ceiling and provides illumination to the walls and floor of a room. In this case, it is desirable that the luminaire provide light in usable directions (for example, toward the surfaces to be illuminated), and the "viewer" or person present in the room will typically be able to directly illuminate the light emitting surfaces so that glare can become an issue when too much light is provided at a certain viewing angle from a sufficiently small emitting surface. While low luminaire costs and architectural designs may result in smaller light emitting surfaces, the requirement for limiting glare will typically dictate a lower luminaire size limit and / or architectural features, such as recessing illumination to obtain the desired level of illumination. Alternatively, conventional work lights provide a light source that is necessarily offset from the viewer's line of sight to prevent the light source from obscuring the object being viewed (e.g., a ring of lights around or around a microscope lens) Head light mounted above or on the side of a viewer's head). The light from such workplace lighting is in the direction of the line of sight of the viewer Angled, but not in line with his / her line of sight. This offset lighting creates shadows and prevents a viewer from viewing certain surfaces, such as the interior of narrow openings. Further, conventional working light also typically requires that a large amount of light be emitted from a necessarily small source, making the light source extremely visible and producing bright spots or glare along the output surface of the working light, as well as reflections of the working light from bright or reflective work surfaces.

The hulse U.S. Patent No. 5,812,714 discloses a waveguide flexure configured to change a direction of movement of light from a first direction to a second direction. The waveguide flexure includes a collector element that collects light emitted by a light source and directs the light onto an input surface of the waveguide flexure. Light entering the curved element is internally reflected along an outer surface and exits the element at an output surface. The outer surface includes beveled angled surfaces or a curved surface that are oriented such that most of the light entering the flexure is internally reflected until the light reaches the exit surface.

Parker et al. reveal in U.S. Patent No. 5,613,751 a light emitting panel array comprising a transparent light emitting panel comprising a light input surface, a light transition region, and one or more light sources. The light sources are preferably embedded or glued in the light transition region to eliminate any air gaps, so that loss of light is reduced and the emitted light is maximized. The light transition region may include reflective and / or diffractive surfaces around and behind each light source to more efficiently reflect and / or diffract and focus light through the light transition region into the light input surface of the light emitting field. A pattern of light extraction deformations or any change in the shape or geometry of the field surface and / or the coating that causes a portion of the light to be emitted may be provided on one or both sides of the field elements. A variable pattern of deformations may break up the light rays so that the internal reflection angle of a portion of the light rays will be large enough to cause the light rays to be either emitted from the field or reflected back through the field and emitted from the other side.

Shipman reveals in the U.S. Patent No. 3,532,871 a combination gradient light reflector having two light sources, each of which, when illuminated, develop light directed at a polished projection surface. The light is reflected on a cone-shaped reflector. The light is reflected transversely into a main body and encounters prisms that direct the light from the main body.

Simon reveals in U.S. Patent No. 5,897,201 various embodiments of architectural lighting distributed by included radially collimated light. A quasi-point source develops light which is collimated in a radially outward direction, and dropouts of the distribution optics direct the collimated light out of the optic.

Kelly et al. describe in the U.S. Patent No. 8,430,548 Luminaires that use a variety of light sources, such as a light bulb, a fluorescent tube and multiple LEDs. A volumetric diffuser controls the uniformity of the spatial brightness and an angular spread of the light from the luminous element. The volumetric diffuser comprises one or more regions of volumetric light scattering particles. The volumetric diffuser can be used in conjunction with a waveguide to extract light.

Dau et al. reveal in the U.S. Patent No. 8,506,112 Lighting devices with multiple light emitting elements, such as LEDs, which are arranged in a row. A collimating optical element receives light developed by the LEDs, and a light guide directs the collimated light from the optical element to an optical extractor that extracts the light.

A.L.P. Lighting Components, Inc. of Niles, Illinois manufactures a waveguide having a wedge shape with a thick end, a narrow end, and two major surfaces therebetween. Pyramidal extraction features (objects) are formed on both major surfaces. The spline is used as an exit shield so that the thick end of the shield is positioned adjacent to a ceiling and the narrow end extends downwardly. Light entering the waveguide at the thick end is directed down and away from the waveguide by the pyramidal extraction members.

Low-profile LED-based luminaires have been recently developed (for example, the ET series Panel Troffers by General Electric) and these use a chain of LED Components that are directed into the edge of a waveguide element (a so-called "edge lighting" approach). However, such luminaires typically have the disadvantage of low efficiency, due to the inherent losses in coupling light emitted by a predominantly Lambertian transmission source, such as an LED component, into the narrow edge of a waveguide plane.

Beeson et al. teach in the U.S. Patent No. 5,396,350 a backlight device used for flat-panel electronic displays. The device comprises a beam waveguide (slab waveguide) which receives light from a light source located adjacent to a side surface thereof and a field of microprisms attached to an end face of the waveguide. Each micro prism has a side surface which is inclined at an angle from the direction normal to the surface of the waveguide. Light emitted by the microprisms is substantially perpendicular to the slab waveguide.

Zimmermann et al. reveal in the U.S. Patent Number 5,598,281 a backlight arrangement for electro-optical displays. Light emitted by a light source disposed within a reflector propagates through an array of apertures and is collimated by an array of wedge-shaped optical elements aligned with the array of apertures , Microlenses are disposed adjacent to the optical elements to further collect and collimate the light. The surfaces of the optical elements are planar or parabolic in shape.

Zimmermann et al. teach in the U.S. Patent Number 5,428,468 an optical illumination system for applications that essentially require collimated light. The system includes a waveguide that receives light from an edge thereof. A field of microprisms is mounted on an end face of the waveguide. Each microprism has at least two sidewalls inclined at an angle from the normal of the surface of the waveguide. An array of microlenses can be placed on top of the array of microprisms to further collimate the light.

Steiner et al. reveal in the U.S. Patent No. 5,949,933 an illumination optical system for collimating light. The system includes a waveguide receiving light from an edge thereof and an array of lens-shaped microprisms mounted on an end face of the waveguide. Each micro prism has a light input surface optically coupled to the waveguide and a light output surface opposite the input surface. The light input surface comprises a number of tapered grooves that are perpendicular to the length of the lenticular microprisms. The system also includes a field of microlenses to further collimate the light.

Hou et. al. teach in the U.S. Patent No. 5,839,823 an illumination system having a light source located adjacent to or within a reflector. A light-alignment arrangement having at least one microprism carried on a base wall is positioned adjacent the light source opposite the reflector. The microprism can be multi-faceted, curved, and polyhedral curved. A lens array may be disposed on the other side of the base wall.

Kuper et al. reveal in the U.S. Patent No. 5,761,355 a light-aligning optical structure comprising a waveguide to which a plurality of prisms are attached. Light deflected by the prisms is confined to a range of angles. The side surface (s) of the prisms may be planar or curved. A field of lenses may be used to spread the light output of the prisms to a wider distribution angle.

SUMMARY

In one aspect, a luminaire includes an optical waveguide having a first surface and a second surface opposite the first surface, and a light source associated with the optical waveguide. At least about 80% of the light generated by the light source is directed by the waveguide into an illumination distribution emitted by the first surface of the optical waveguide.

In another aspect, a luminaire includes a waveguide having a first surface and a second surface opposite the first surface. The waveguide includes an extraction feature disposed on the first surface. The luminaire further includes a light source associated with the waveguide. Light emitted by the light source is directed by the waveguide into an illumination distribution emitted from the first surface of the waveguide. Further, the waveguide is optically transparent such that the illumination distribution is visible along a line of sight through the waveguide extending from the second surface to the first surface.

In another aspect, a luminaire includes a housing, an LED element disposed within the housing, and a waveguide having a light emitting surface disposed in the housing adjacent to the LED element. An extraction feature is disposed on the light emission surface of the waveguide. The extraction feature has a curved shape extending between an opening adjacent the light emission surface and a base opposite the opening.

Other aspects and advantages will become more apparent upon a consideration of the following detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings show:

1 an isometric view of an embodiment of a lamp in a room;

2 an isometric front view of the light of the 1 ;

2A an exploded view of a housing of the light of 1 ;

3 a back isometric view of the light of the 1 ;

4 a broken front elevation view of the light of the 1 ;

5 a cross-sectional view of the lamp of 1 , generally along the section lines 5-5 of 2 ;

6 an enlarged side elevational view of a waveguide of the light of 1 ;

7 a broken isometric view of an embodiment of extraction features in the luminaire of 1 be used;

8th a side elevational view of the extraction features of 7 ;

9A and 9B a Seitenevevationsansicht and a plan view of the extraction features of 7 before application to a waveguide;

10A - 10C a side elevation view, a top view, and a side elevation view respectively of the extraction features of the 7 after application to a waveguide;

11A - 11C an isometric view, a side elevation view and a top view of another embodiment of an extraction feature before application to a waveguide;

12 an enlarged side elevational view of a waveguide of the light of 1 ;

13 an enlarged side elevational view of a waveguide of another embodiment of a lamp; and

14 4 is a graph showing a light illumination distribution as a function of the extraction feature height of the luminaire 1 represents.

DETAILED DESCRIPTION

Referring to 1 is a lamp 50 shown a lighting distribution 52 with a hidden lighting 53 provides. The lamp 50 includes an optical waveguide 54 with a first surface 56 and a second surface 58 , which are opposite to the first surface 56 is. At least 80%, preferably at least 90% and more preferably at least 95% of the light emitted by a light source 60 ( 4 ) is generated by the waveguide 54 in the lighting distribution 52 directed by the first surface or the light emission surface 56 of the waveguide 54 is sent out. Furthermore, the illumination distribution 52 through the waveguide 54 along a line of sight 62 extending from the second surface 58 to the first surface 56 extends, visible. The waveguide 54 shows a lighting 53 from the second surface 58 along the line of sight 62 which is less than 20%, preferably less than about 10%, and more preferably less than about 5% of the total brightness of the luminaire. In general, "hidden lighting" refers to the visibility of the lighting distribution 52 along the line of sight 62 through the waveguide 54 while the lighting 53 from the second surface 58 along the line of sight 62 during use (ie when to the light source 60 ( 4 ) Energy is delivered) is minimized. The line of sight 62 can to the first and second surface 56 . 58 of the waveguide 54 be vertical or angled. Still further, simulations have shown that the embodiments described herein provide an optical efficiency of at least 90%, and in particular at least 95%.

As in 2 it can be seen that the waveguide stretches 54 the light 50 from a case or enclosure 64 , the / the first part 66a and a second part 66b having. In the illustrated embodiment, the first and second parts 66a . 66b identical in shape and oriented in opposite directions during use to be coupled together. As in 2A As can be seen, each part comprises 66a . 66b a peripheral edge 70a . 70b extending inward along first, second and third surfaces, respectively 72a . 72b . 74a . 74b ' respectively. 76a . 76b extends. The first and the second part 66a . 66b are oriented relative to each other such that the first and third surfaces 72a . 76b and 72b . 76a fit each other. Two screw holes 78 are along the third surfaces 76a . 76b formed and two depressions 80a . 80b are along the first surface 72a . 72b formed to with the two screw holes 78a . 78b the corresponding part together. Every second surface 74a . 74b includes a raised portion 74a-1 . 74b-1 and a lowered section 74a-2 . 74b-2 with the raised and lowered sections of the corresponding second surface 74a . 74b match. The fourth surfaces 82a ( 4 ) 82b ( 2A ) are spaced apart so as to allow the waveguide thereof 54 extends. A recess 83 is adjacent to the second surfaces 74a . 74b the first and second parts 66a . 66b formed and a light source element 83a is arranged in it. The first and second parts 66a . 66b be through fasteners 85 held together, although any suitable fastening means may be used. A lit surface of an object 87 is through the waveguide 54 seen and from the light 50 illuminated.

Referring to 3 are extraction characteristics 84 on the first page 56 of the waveguide 54 arranged. In some embodiments, the extraction features are 84 not visible to viewers in the room. In other embodiments, the extraction features are arranged in a regular field, such as a narrow packing hexagonal field. In still other embodiments, the extraction features are arranged in a specific pattern (density pattern) to improve optical efficiency, uniformity of illumination, or providing a desired visual effect, image, or illumination pattern (logo, image, graphics, etc.).

4 shows LED elements 86 that in a first end 88 of the housing 64 adjacent to the second surface 74a of the first part 66a are arranged. The waveguide 54 extends from a second end 90 of the housing 64 opposite to the first end 88 that of the fourth surfaces 82a . 82b

( 2A ) of the first and second parts 66a . 66b ( 2A ) is formed. In the illustrated embodiment, the waveguide becomes 54 along a coupling surface 92 through the multitude of LED elements 86 enlightened on the edge. The LED elements 86 are on a printed circuit board 94 attached to the light source element 83a and spaced from the coupling surface 92 of the waveguide 54 is appropriate. Other types of coupling and / or orientation of the LED elements 86 relative to the waveguide 54 can be used. In alternative embodiments, the luminaire 50 comprise more than one waveguide and may use a coupling with an inner illumination, a coupling at several edges, or a combination thereof. The type of coupling can affect the angular and spatial distribution of light within the waveguide, which in turn can affect the efficiency of extraction, illumination, and brightness.

Various types of LED elements can be used, including LED packages with primary optics, as well as bare LED chips. Each LED element or module 86 may be a single white LED or an LED of a different color, or may each comprise a plurality of LED elements, either separately or mounted together on a single substrate or package to form a module including, for example, at least one phosphor precoated LED either alone or in combination with at least one colored LED, such as a green LED, a yellow LED, a red LED, etc. In those cases where soft or warm white illumination is to be generated, any LED element or module may be used 86 or a plurality of such elements or modules comprise one or more blue-shifted yellow LED elements and one or more red LED elements. The LED elements 86 can be arranged in different configurations and / or layouts as desired. Different color temperatures and appearances may be produced using other LED combinations, as is known in the art. The light can be LEDs 65 with the same type of phosphor converted white LED, or any combination of the same or different types of LEDs discussed herein. In some embodiments, a luminaire may include a plurality of groups of LEDs 65 include, each group LEDs 65 with different colors and / or color temperatures. The groups of LEDs 65 may be separated by dividers as described in U.S. Patent Application Serial No. ** / ***, ***, filed August 28, 2014, entitled "Luminaire Utilizing Multiple Edge Coupling" (Cree Serial No. P2346US1) here by reference is part of the present application, the LEDs 65 are arranged within the coupling cavity. Such dividers facilitate the mixing of light between adjacent LEDs 65 , limit the angle of incidence of the light incident on the first and second coupling surfaces XX of the waveguide, and reduce interaction and light absorption between LED components 65 , In embodiments with LEDs of the same or similar color, dividers may not be required or desired. Further, the light source in one embodiment, any LED, for example, an MT-G LED, which includes a True White ^® LED technology, or as disclosed in the US Patent Application No. 13 / 649.067, which on October 10, 2012, entitled "LED LED Package with Multiple Element Light Source and Encapsulant Having Planar Surfaces" was filed by Lowes et al. (Cree reference P1912US 1-7), the disclosure of which is incorporated herein by reference as developed and manufactured by Cree Inc., the assignee of the present application. If desired, a side emitting LED included in the US Patent No. 8,541,795 are disclosed, the disclosure of which is incorporated herein by reference. In some embodiments, each LED element or module 86 include one or more LED elements formed vertically within the coupling cavity. In any of the embodiments disclosed herein, the LED element (s) or module (s) may be used. 86 have a Lambertian or nearly Lambertian light distribution, although each may have a directional emission distribution (eg, a laterally emitting distribution) as needed or desired. More generally, any Lambertian, near Lambertian, symmetrical, wide-angle, preferred-side, or asymmetric-beam patterned LED (s) may be used for the light source.

Referring to the 5 - 8th becomes light predominantly from the first surface 56 of the waveguide 54 by the attached or glued extraction features 84 extracted. Each extraction feature 84 includes a body 96 ( 7 ) with a curved shape 98 that is between an opening 100 adjacent to the first surface of the waveguide 54 and a base 102 the opening 100 extends opposite. The opening 100 and the base 102 may be parallel to each other or may be disposed at an angle relative to each other. As in 6 It can be seen to include the curved shape 98 an outer surface 104 that is relative to the first surface 96 of the waveguide 54 is undercut. The outer surface 104 may include planar surfaces, curved surfaces, planar surfaces that approximate a curve, or a combination thereof. The outer surface profile may be symmetric in nature (for example, as in the case of a hemisphere) or asymmetric (as in the case of an ellipse or other combination of shapes). The extraction features and / or the waveguide may be acrylic, with an acrylic UV-curable resin, silicone, polycarbonate, glass, or any other suitable material (materials) and combinations thereof, possibly in a layered arrangement, to provide a desired effect achieve.

In the in 6 to 8th In the embodiment shown, the extraction features 84 on an element 108 be formed, which thereafter to the first surface 56 of the waveguide 54 glued or optically connected in another way. The element 108 may be a film, a glass, an acrylic, or any suitable optically transmissive material. For example, the element 108 an acrylic, polyethylene terephthalate (PET) or polyester based film (e.g. under the trademark "Mylar") or a film of any other suitable material on which extraction features are formed or replicated. The extraction characteristics 84 may comprise a suitable optical material such as acrylic, acrylic-based resins, polycarbonate, glass, or other materials having suitable optical and structural properties. The film may be made using any one of a variety of techniques typically employed in the formation of micro-optic films, including punching, photolithography, grayscale lithography, micro-replication, injection / compression molding, reactive Ion heating, a chemical punching, a casting process or a drum roll transfer. Other methods of manufacture include pouring an acrylic-based UV-curing resin or silicone material onto a carrier film which is subsequently cured to form extraction features. The resulting extractor film or extractor layer may be attached to the first surface 56 of the waveguide 54 laminated or otherwise applied, either directly or with one or more intermediate layers, using a variety of bonding methods, including ultrasonic bonding, laser bonding, adhesive bonding, pressure sensitive adhesive bonding, chemical bonding and thermal bonding.

In some embodiments, the extraction features 84 on the waveguide 54 without an element 108 to be ordered. For example, the extraction characteristics 84 directly on the first surface 56 of the waveguide 54 help an intermediate layer for patterning, as described in U.S. Patent No. 8,564,004, issued October 22, 2013, entitled "Complex Primary Optics with Intermediate Elements" by Tarsa et al (Cree reference P1445) This patent is hereby incorporated by reference in the present application. Using this preparation method, the extraction characteristics become 84 optically with the waveguide 54 connected, without the need of the substrate 108 , The pattern generation layer may be used by any method such as a molding process, injection molding, compression molding, pouring, stencil printing, three-dimensional printing, photolithography, deposition, and the like. In particular, the pattern generation layer becomes on the first surface 56 of the waveguide 54 formed and includes holes or openings, where the waveguide 54 is exposed. The openings of the pattern generation layer correspond to the locations where the extraction features 84 on the waveguide 54 should be formed. In some embodiments, a mold then becomes over the pattern generation layer and the first surface 56 of the waveguide 54 applied. The mold includes voids aligned with the openings of the pattern generation layer to define voids. The cavities become with the material of the extraction characteristics 84 filled. In other embodiments, the material becomes the extraction feature 84 attached to the openings of the pattern generation layer prior to the placement of the mold on the pattern generation layer. In any case, then the material of the extraction feature 84 at least partially cured and the mold is removed. The material of the pattern generation layer may include polyvinyl alcohol, a poly (methyl methacrylate) (PMMA), one or more photoresist materials, or other suitable materials. The pattern generation layer may be by water rinse, heat, evaporation, processing, developer and solvent, chemical etch / solvent, plasma etch, or any process involving the waveguide material 54 and / or the extraction characteristics 84 does not attack, be removed. Alternatively, the waveguide 54 , the extraction characteristics 84 and / or the element 108 be bonded to each other through one or more additional layers, such as an adhesive layer or a pressure-sensitive adhesive film.

The optical efficiency, directivity, brightness and illumination of the waveguide-based luminaire are sensitively dependent on the particular geometry and arrangement of the extraction features 84 from. One class of extraction feature geometries that is particularly useful for a range of lighting applications includes a roughly "spherical" profile, as in FIG 11A - 11C shown, wherein this profile consists of a cut-off curved surface, such as a truncated hemisphere with an adjacent cylindrical or conical base. This particular geometry provides a maximum degree of directionality as well as a range of possible illumination distributions that can be realized by changing the height to which the curved surface is cut. Referring to 8th corresponds to the section height H1 of the extraction feature 84 a gap 106 between the first surface 56 of the waveguide 54 and the base 102 the extraction feature 84 , In some embodiments, the section height is H1 (resulting in a near hemispherical upper extractor section with a small flat surface at the top) and light becomes predominantly perpendicular from the first surface 56 of the waveguide 54 extracted to form a "Spot Light" distribution. In other embodiments, light may be extracted by varying the height H1 to form a Lambertian distribution or into a "split" distribution where light is predominantly in one direction more parallel to the waveguide 54 is emitted. A change in the dimension of the gap 106 leads to a change in the illumination distribution 52 as described in U.S. Patent Application No. ** / ***, ***, issued August 28, 2014, entitled "Luminaire with Selectable Luminous Intensity Pattern" by Tarsa et. al. (Cree file reference P2262US1). In some embodiments, the gap may range from about 10 μm to about 590 μm, preferably from about 100 μm to about 550 μm. In the case of a purely hemispherical extraction feature 84 with no cylindrical or conical base can the gap 106 in a range from 95% of the radius of the hemisphere to 5% of the radius of the hemisphere, preferably from 80% of the radius of the hemisphere to 20% of the radius of the hemisphere. By adding a conical base to the hemisphere, as in 11 As shown, the directivity of the emitted light can be further increased. As in 14 shown generates the light 50 with extraction features 84 , as in 11A . 11B and 11C 5, a luminous intensity pattern or distribution coinciding therewith with the feature height H1 or the gap 106 changed. In the 14 shown luminous flux distributions assume that the extraction characteristics 84 all have substantially the same shape. As in 14 As can be seen, the luminous intensity pattern changes from an asymmetrical distribution at feature heights H1 of about 170 μm to a work lighting or "spot light" distribution at a feature height of about 560 μm. In In this case, the asymmetry with respect to the vertical axis in the illumination distribution representation refers to the positioning of the source along an edge of the waveguide. A more symmetrical pattern (mirrored, for example, on the vertical axis in the illustration) would result from illuminating the waveguide from two opposite edges. In general, the variants in the illumination result from variants in the optical coupling surface and the extractor opening area between the extraction features 84 and the waveguide 54 , as the cross-sectional dimensions of the transition between features 84 and the waveguide with the height H1 of the extraction feature (the truncation).

Referring to 8th . 9A . 9B . 10A . 10B and 11A - 11C For example, the addition of a cylindrical or conical extension to the base of the hemisphere may increase the directivity of the emitted light, while a simple truncated hemispherical extractor shape may provide a range of desirable illumination distributions. This directional characteristic (ie the part of the light coming from the first side 56 the waveguide relative to the part of the light from the second side 58 is emitted) is important for the realization of lights with a hidden lighting. In the example that is in 9A and 9B includes the extraction feature 84 a first section (a first part) 112 adjacent to the opening 101 and a second section (second part) 114 adjacent to the base 102 , In a more general case, the first part or section needs to 112 not be hemispherical and the second part 114 or the second section 114 may be cylindrical, conical or curved, as desired. The first paragraph 112 may have a height that ranges from about 5 μm to about 2 mm. The second section 114 may have a height that is in a range of about 5 μm and about 2 mm, although some embodiments include a second portion 114 can not include. The forms 112 and 114 may be formed circumferentially, so that the cross-section transverse to a central axis 118 ( 9A ) over the entire height H1 ( 8th ) of the extraction feature 84 is circular. Alternatively, the forms 112 and 114 have non-circular cross-sections (for example, elliptical or faceted). In some embodiments, the base diameter d _{b of} the extraction feature 84 be about twice a height H1.

In other embodiments, the first portion or the first part 112 be designed to redirect incident light down through total internal reflection (TIR). A form of extraction feature 84 can be determined by plotting the points using a differential or quasi-differential equation. An interactive process includes the steps of defining a starting point at coordinates r, h, calculating a slope required to achieve total reflection, and based on the calculated slope, further calculating the required incremental radial step Δr, which is one predetermined incremental height change Δh, advancing to a next point r + Δr and h + Δh, and repeating the calculation and movement steps until the desired total height is reached. In other embodiments, the shape of the extraction feature 84 using geometric and / or differential equations, possibly in combination with other curved, planar or piecewise linear surfaces.

An example of the above-mentioned interactive process comprises the use of equations 1 and 2, which are given below and are input to an optimization routine such as solver Microsoft Excel ^®. In general, a profile of the extraction feature 84 by calculating a series of slopes dh / dR at incremental points 202a . 202b , ... 202N along an outer surface 116 of the first section 112 the extraction feature 84 Are defined. The outer surface 116 then becomes the central axis 118 turned to the extraction feature 84 define. Equation 1:

Equation 2:

• Slope = dh / dR = tan (φ + α)

(Slope). In Equations 1, the sharpest angle φ of a ray of light incident on a given point becomes, for example 202d , on the outer surface 116 certainly. As in 10C The sharpest angle φ can be seen by a light beam 204 defined in the opening 100 on an edge 206 opposite to the point 202d occurs, and becomes relative to a surface normal 208 the opening 100 measured. The angle φ is based on the coordinates of the point 202d relative to the entrance of the light beam 204 into the extraction feature 84 on the edge 206 the opening 100 calculated. Especially points the point 202d a Y coordinate value h relative to the respective waveguide surface 56 and an X coordinate value R ₀ + R, where R _{0 is} a distance from the edge 206 to the central axis 118 (ie, an opening radius) and R is a distance from the central axis 118 to the point 202d is.

Using the equations 2 then becomes the slope dh / dR at the point 202d along the outer surface 116 calculated. Equation 2 ensures that the resulting angle of incidence δ is normal to a surface 210 at the point 202d the critical angle θ relative to the surface normal 210 does not exceed. As in 10C the angle α is shown to be complementary to the critical angle θ. In the illustrated example, the resulting angle of incidence is δ of the light beam 204 about the same or greater than the critical angle θ, so that the light beam 204 through the outer surface 116 the extraction feature 84 totally reflected and through the base 102 is emitted from it.

Once the slope dh / dR for the point 202d is calculated, the angle φ is calculated using Equation 1 for the next point 202e with incremental changes Δh, ΔR along the x and y coordinates h, R. The slope dh / dR for the point 200e is then determined using Equation 2 and the process is repeated until a known parameter is met, for example, as soon as the height distance h exceeds the height F (FIG. 10A ) of the first section 112 , or in some cases the total height F + G ( 10A ) of the extraction feature 84 reached. The incremental change Δh may be in a range of about 1 nm to about 1 μm or may be a fraction such as 1/50 of the total height F + G (FIG. 10A ) of the extraction feature 84 be.

In some embodiments, Equation 2 may be implemented with a conditional test to specify an upper bound of the slope dh / dR. The upper limit may be used instead of the calculated slope, as desired. For example, with reference to 10C , the upper limit can be specified as an angle β passing through an outer surface 122 of the second section 114 relative to the base 102 is defined. Once the calculated slope dh / dR of points 202 along the outer surface 116 of the first section 112 reaches the upper limit of the angle β, each slope dh / dR for the subsequent points 202 along the outer surface 122 of the second section 114 constant and equal to β so as to form the conical shape.

In some embodiments, the optimization routine may calculate the opening area radius R ₀ for a preferred area ratio (ie, opening area to base area ratio) depending on user-defined conditions, such as the total height F + G (FIG. 10A ), the critical angle θ (based on the relative refractive indices), and the desired smallest angle φ _min , defined by the sharpest angle φ of a light beam 212 that's on the point 204 on the outer surface 132 at the base 122 the extraction feature 116 incident. Other user-defined conditions can be specified as desired. In one embodiment, the outer surfaces guide 124 . 132 Constructed in accordance with the above description, an extraction of over 95% of the light from the first surfaces 62a . 64a of the waveguide 42 out.

In the in 7 and 8th The exemplary embodiment shown may include the plurality of extraction features 84 in a hexagonal field pattern on top of the element 108 , be formed. Other patterns may be used to produce a desired illumination distribution. The extraction characteristics 84 may be irregularly spaced, or some may be regularly spaced and others irregularly spaced, etc. The thickness T1 of the element 108 may be in a range of 10 μm to 5 mm, preferably 250 μm to 2 mm. The center-to-center distance D1 between adjacent extraction features 84 may be less than twice the feature radius (for example, overlapping features) to 10 mm, preferably twice the feature radius to 5 mm. The thickness T1 and the distance D1 may be constant or may be over the first surface 56 of the waveguide 54 change. The shape, size and density of extraction features 84 can be over the surface 56 of the waveguide 54 in either a regular or irregular manner to produce a desired illumination distribution. For example, a variety of elements 108 or films that have differently shaped extraction features 84 to the waveguide 54 be bound to produce an asymmetric illumination distribution. The opening diameter there, the base diameter d _b and the heights H of the extraction features 84 they can all be the same or may be different and may be above the surface 56 of the waveguide 54 change to produce different lighting patterns as desired. Further, it may be desirable to fabricate various levels of roughness or specific optical features, such as a second set of or a field of geometric features on an outer surface 110 of the element 108 to further provide control over the brightness and illumination distributions. In other embodiments, the extraction features 84 be positioned to the Brightness or illumination of both first and second surfaces 56 . 58 to extract.

9A and 9B illustrate the body 96 the extraction characteristics 84 before a bonding on the first surface 56 of the waveguide 54 , The first outer surface 116 of the first section 112 is about a central axis 118 turned. The curvature of the first section 112 the extraction feature 84 is designed to minimize the amount of light that enters the waveguide 54 back either directly from the extraction feature 84 or indirectly from an adjacent section 120 ( 7 ) of the element 108 between extraction features 84 is redirected. Such minimization leads to a high extraction efficiency from the first surface 56 of the waveguide 54 out (a high directional characteristic). In the illustrated embodiment, the curved shape is defined by Equations 1 and 2.

A second outer surface 122 of the second section 114 has a conical shape that forms an angle β with the base 102 forms. The angle β may be in a range of 1 ° to 90 °, preferably 60 ° to 90 °. Furthermore, the body can 96 a bond feature 124 Cover, the top of the opening 100 is formed to bond the extraction feature to the waveguide surface 56 to facilitate or facilitate. The actual geometry of the bond feature 124 may change depending on the particular binding approach that is used. For example, the bonding feature 124 be convex in nature (as in 9A ) so as to limit the formation of trapped air bubbles at the interface when a liquid or gel-like adhesive layer is used to bond the film to the waveguide. The construction of the bond feature 124 can also be such that the displacement of the adhesive is minimized during a connection, whereby a "threading" of the offset adhesive along the first and second section 112 . 114 is minimized where it could interfere with the optical function of these surfaces. In general, it is intended that part of the bond feature 124 or the entire bond feature 124 becomes optically inactive after the bonding process, so that it has minimal impact on the resulting light distributions and efficiency. A similar bond feature 124 is with the extractor geometry of 11 shown. In an alternative embodiment, the bonding feature 124 comprise an adhesive material which serves to provide the extraction feature to the first surface 56 of the waveguide 54 to bind.

10A and 10B illustrate the extraction feature 84 of the 9A and 9B as adhered to the first surface of the waveguide. Exemplary dimensions of the extraction feature of the 9A . 9B . 10A and 10B are given below. In one embodiment, a luminaire having a plurality of extraction features extracts the light 10A and 10B about 97% of the brightness 52 from the first surface and about 3% of the brightness 53 from the second surface. Table 1 FIG. 9A A 33 μm B 5 μm C 53.26 μm e 16,716 μm β 70 degrees FIG. 10A F 13.95 μm G 14,050 μm H 53.26 μm J 26,716 microns β 70 degrees

The 11A - 11C illustrate another embodiment of an extraction feature 184 , The first paragraph 112 of the body 96 has a hemispherical shape, although other geometries, such as a parabolic shape, free-form curves, planar and / or piecewise linear shapes can be used to produce a lighting pattern as desired. The second section 114 has a nearly cylindrical chronic shape, although other shapes can be used as desired. Similar to the feature of 9A and 9B becomes the bond feature 124 on the opening 100 formed to form a bond of the first surface 56 to the waveguide 54 to enable. Exemplary dimensions of the extraction feature of the 11A - 11C are given in Table 3. In another embodiment, a luminaire with a variety of extraction features extracts the 11A - 11C about 94% of the brightness 52 from the first surface and about 6% of the brightness 53 from the second surface. Table 2 K 0.05 mm L 0.415 mm M 0.085 mm N 1 mm P 0.05 mm Q 0.510 mm radius of curvature θ 89 degrees

In still further embodiments, the extraction features 84 have an asymmetrical shape. For example, the first section 112 the extraction feature 84 be hemispherical and the base 102 can be elliptical, so the feature 84 as a truncated hemisphere appears when viewed from any cross section but appears as an ellipse or oblong circle when viewed from above. Such asymmetric geometry would result in an asymmetrical illumination pattern, as may be desirable for certain applications, such as street lighting. Furthermore, the extraction characteristics 84 with an asymmetrical cross section along the height H1 (ie coplanar with the central axis 118 ) Direct light in certain directions or quadrants below the light. extraction features 84 with segmented cross-sections and upper profiles consisting of a combination of curved surfaces and linear surfaces (such as an extractor that appears as a truncated hemisphere from the side but appears from above as a star or faceted shape) be used for specific lighting applications requiring a very unique and defined lighting distribution (for example stage lighting, architectural lighting or side lighting). Finally, extraction features that have a generally conical or parabolic shape (symmetric or asymmetric, truncated or not) can produce better collimated light rays in specific directions (e.g., for a direct / indirect pendant, downlight, etc.).

The extraction characteristics 84 , in the 6 - 11C and are referred to herein as "apertured extraction features" provide significant advantages in terms of control of illumination distribution, efficiency and directivity. As in 12 As shown, light extracted from the waveguide first enters the extraction features 84 through the openings 100 of which on the light emission surface 56 of the waveguide 54 one. Light rays hit the opening 100 only on after moving from another surface 58 of the waveguide 54 the light emission surface 56 to be totally reflected opposite. In contrast, the conventional (non-scattering) extraction features, such as steps, hemispherical bumps or depressions formed directly on the waveguide surface, generally result in optical surfaces exposed to light from both surfaces 56 and 58 of the waveguide 54 that has to come into play, interact and control it. In other words, light generally impinges on the surfaces of such conventional extraction features after being totally reflected from the other surface and also totally reflected from the surface immediately surrounding the recess. Since the optical surfaces of the extractor must treat light incident from substantially opposite directions, it is difficult to control illumination distributions over a range of illumination patterns having a high extraction efficiency and high directivity (for example, from a single surface).

While using the extraction feature provided with one or more openings 84 In the present application, a control over the primary direction of the light rays on the extraction features 84 In some applications, it may also be desirable to further control the distribution of angles about the primary directions within the waveguide. Such control can be achieved generally over a number of optical surfaces, such as the primary optic or lens of the LED element, the coupling surface of the waveguide, and so on. Controlling the angular distribution of light within the waveguide and judicious construction of the extraction features along with the waveguide coupling surfaces and the primary component optics may further provide control over the emitted brightness distribution, illumination distribution, optical efficiency, and directionality of the luminaire. Even in cases where light within the waveguide is not well controlled, the apertured extraction features can provide improved control of the distribution and efficiency of the extracted light. In either case, highly controlled beams can either be extracted in a collimated manner or distributed in a wide distribution for different selectable illumination patterns depending on the slit.

Taken together, a number of factors may affect the illumination distribution emitted by the waveguide. The shape of the extraction feature, together with the distance and pattern of the plurality of extraction features, affect the extraction efficiency, the amount of light emitted from the first surface of the waveguide (the directional characteristic), the brightness, and the illumination of the luminaire. For example, an asymmetrically-shaped extraction feature may be asymmetric Produce illumination distribution. In cases where the geometry of the extractor is representative of a truncated feature, such as a truncated hemisphere, the section height - which affects the distance (s) between the first surface of the waveguide and the base (s) of the extraction feature (FIG Extraction characteristics), significantly matches the illumination distribution pattern. For example, the lamp generates the 2 an asymmetric distribution when the distance is about 125 μm, while the lamp produces a more symmetrical distribution when the distance is about 600 μm. In other embodiments, a change in pitch may result in a "Spot Light", a "Lambertian" or a "Wall Wash" illumination distribution. Another consideration in the construction of such extractors is the primary direction in which the light propagates through the waveguide. In an extreme comparison, a square waveguide illuminated by a single edge may produce an asymmetrical illumination pattern, whereas a circular waveguide illuminated around its circumference will produce a highly symmetric illumination pattern. Various types of lamps and lights, including those requiring dispersive or Lambertian illumination distribution (eg, typically ceiling lights for general lighting), collimating distributions (e.g., downlights or spotlights), and specific lighting patterns (e.g., street lighting, architectural lighting) may be used using the optical waveguide and the extraction features provided herein.

Referring again 12 includes the lamp shown 50 the waveguide 54 , the extraction characteristics 84 , and the element 108 which comprise the same material, so that the refractive index is consistent. In this case, light is not broken when passing through the opening 100 emotional. In contrast illustrated 13 a variety of extraction features 84 and an element 108 on a waveguide 54 , where the material of the waveguide 54 different from the material of the extraction characteristics 84 and the element 108 different. In this case, light will be emitted when it comes from the waveguide 54 in the extraction characteristics 84 spread in, broken. In still other embodiments, an area may be 126 ( 13 ) between extraction features 84 after attachment to the waveguide 54 partially or totally comprising a material other than air. For example, the material may have a refractive index significantly different from that of the waveguide 54 and the element 108 different. Still further, the refractive index of the element 108 be different than the waveguide 54 and / or the extraction characteristics 84 to achieve refraction at such transitions (cut surface). In some embodiments, it may be desirable to use refraction to control the extraction and the resulting illumination distribution.

Other parameters, such as the shape, density and material of the extraction features, can also be altered to produce different illumination patterns. Other methods of providing directional light extraction, such as combinations of refractive index differences in the waveguide or elements attached to the waveguide, and modifications to the shape of the waveguide itself, could also be used to alter the illumination pattern. Further, a multi-layered protective material may be optionally attached to the first and second surfaces. This protective material may be removed one layer at a time during use of the luminaire to rapidly provide a clear (i.e., transparent) viewing / emission surface in dirty working environments.

The high degree of light directivity afforded by the proper construction of the apertured extraction features opens up a wide range of potential lighting applications. For example, higher-level emission may allow a viewer to view a reflective surface through the waveguide without significantly obscuring his or her vision by the illumination or emitted light of the luminaire. In particular, a viewer may look through the luminaire at an illuminated area, as in FIG 1 shown. In addition, the viewer can see the illumination that results from the luminaire without seeing significant brightness, even while the second surface from which light is emitted is visible to the viewer. The luminaire may also provide high levels of light from a surface source (rather than a point source), obscuring the light source and / or reducing or eliminating direct glare from the source, as well as reflected glare away from the surfaces.

The concept of hidden illumination with visible illumination enabled by the light directivity has many applications in the field of architectural and display lighting. For example, in one embodiment, a cladding for a work of art may comprise a glass or acrylic waveguide having a lenticular microfilm film bonded thereto which is mounted within a frame, the light sources for the art Waveguides are arranged within the frame. The waveguide serves both as protection for the art and as a luminaire for illuminating the art in a manner in which the light source is not evident. Light extracted through the film toward the art provides uniform illumination of the art without the use of external light sources, while allowing a viewer to peer through the glass or acrylic waveguide. Similarly, such approaches could be used in a variety of display cases, aquariums, etc.

In another embodiment, a luminaire that allows for hidden lighting can illuminate a room. The luminaire may comprise a waveguide of a clear material, such as glass or acrylic, with extraction features, such as the microfilm lensing film bonded thereto. An array of LED elements may be placed on one or more edges of the waveguide. The waveguide may have a thickness of about 1/8 inch and may be about 6 inches by about 24 inches, about 2 feet by about 2 feet, or about 2 feet by about 4 feet, although other dimensions may be used as desired. The luminaire may be positioned to provide illumination to preferred surfaces in the room, such as a wall, floor, ceiling, and arranged such that the lighting is directed away from people in the room. In one embodiment, a luminaire may be mounted to a ceiling with the light emitting surface of the waveguide directed toward the wall. The lamp may be about twelve inches away from the wall so that the wall is illuminated. The reflection of the light from the wall illuminates a portion or the entire space, awakening the appearance that the surfaces are illuminated without any obvious or visible source of illumination. In other embodiments, the luminaire may be constructed to provide specially tailored and / or adjustable illumination patterns. In general, such light sources would be "indirect" in the sense that a surface is illuminated while the illumination is hidden from view. Exemplary applications would include a pendant lamp, side lighting, sconce, ceiling lighting, workstation lighting, track lighting, floor lamps, etc.

The lamp could be used in a variety of other applications. For example, a work light that uses the light allows a viewer to align the line of sight of the viewer with the light distribution produced by the light. The work light illuminates a surface while allowing the viewer to look directly at the illuminated surface through the waveguide and not around it. The viewer might see features such as drilled holes or other deep openings. Such a luminaire is in contrast to a conventional work light, which must necessarily be positioned out of the viewer's direct line of sight so that the work light would not fully illuminate the interior of the hole or other deep openings. Another example is glasses or goggles that emit light away from the viewer while light is projected back into the viewer's eyes.

In yet another example, a luminaire could appear to be a clear panel when viewed from practical locations within a room while illuminated toward a wall, ceiling, desk, workspace, or other surface or another object is provided. For a common observer, the luminaire would give the impression that the light is produced with no visible source, providing flexibility in architectural design, aesthetic enhancement, and reduction in glare. Additional applications include a face shield, a dirt guard on a salad bar, a window that illuminates an outside area without the need for an external lighting system and external wiring, or a security window that appears as a light to the persons of a room, but outside viewers of the room allows to see inside. Still further, the luminaire may be mounted to a ceiling panel or suspended from a ceiling using a pendulum attachment device. Each embodiment may include piezoelectric materials and suspended particulate devices that either include adjustable extraction features and / or allow the extraction features to be adjustable. Such adjustability would allow a variable brightness and / or a variable illumination pattern.

Any of the embodiments disclosed herein may include a power supply circuit including a buck regulator, a boost regulator, a buck-boost regulator, a SEPIC power supply, or the like, and may include a driver circuit as disclosed in U.S. Patent Application Serial No. 14 / 291,829 . filed on May 30, 2014, entitled "High Efficiency Driver Circuit with Fast Response" by Hu et al. (Cree Serial No. P2276US1, Attorney Docket No. 034643-000618) or US Patent Application Serial No. 14 / 292,001, filed May 30, 2014, entitled "SEPIC Driver Circuit with Low Input Current Ripple" by Hu et al. (Cree reference P2271US1, Attorney Docket No. 034643-000616), which are incorporated herein by reference. The circuit may also be used with light control circuitry that controls a color temperature of any of the embodiments disclosed herein in accordance with the input of a viewer, as in US Patent Application Serial No. 14 / 292,286, filed May 30, 2014 entitled "Lighting Fixture Providing Variable CCT" by Pope et al. (Cree reference P2301US1), which is incorporated herein by reference.

Further, any of the embodiments disclosed herein may include one or more communication components that form part of the light control circuitry, such as an RF antenna that detects RF energy. The communication components may be incorporated, for example, to allow the luminaire to communicate with other luminaires and / or with an external wireless controller, as in US Pat US Patent Application Serial No. 13 / 782,040 filed on May 1, 2013, entitled "Lighting Fixture for Distributed Control," or US Patent Application Serial No. 61 / 932,058, filed January 27, 2014, entitled "Enhanced Network Lighting," both of which are incorporated herein by reference Names of the assignee of the present application and the disclosures of which are incorporated herein by reference. More generally, the control circuitry includes at least a network component, an RF component, a control component, and a sensor. The sensor, such as a button-shaped sensor, may provide an indication of ambient light levels thereon and / or occupancy within the space or the illuminated area. Such a sensor can be integrated into the light control circuitry.

INDUSTRIAL APPLICABILITY

The extraction features disclosed herein efficiently extract light from the waveguide. At least some of the luminaires disclosed herein are particularly adapted for use in installations such as outdoor fixtures (e.g., street lamps, hall lights, roof lights) and fixtures in buildings (e.g., down lights, ceiling fixtures, fold-in or fold-out applications, one on one Surface mounted application on a wall or ceiling, etc.), which preferably has an output of the entire luminaire of at least about 100 lumens or greater and in some embodiments a total luminaire output of at least about 3000 lumens and in other embodiments a total lumen output of about 10,000 lumens to about Require 20,000 lumens. For example, in some industrial and business lighting applications, such as storage lighting, a total lumen output of up to 10,000 lumens could be desired. Further, the lights disclosed herein preferably have a color temperature of between about 2500 ° Kelvin and about 6200 ° Kelvin, and in some embodiments between about 2500 ° Kelvin and about 5000 ° Kelvin, and in other embodiments 2700 or 3500 ° Kelvin. At least some of the luminaires disclosed herein also preferably exhibit an efficiency of at least about 80 lumens per watt, more preferably at least about 100, and most preferably 120 lumens per watt. Further, in some embodiments, the waveguide or waveguides exhibit an optical efficiency of at least about 80%, preferably at least 90%, and more preferably at least about 95%. Further, at least some of the luminaires disclosed herein preferably exhibit an overall efficiency (i.e., light extracted from the waveguide divided by light injected into the waveguide) of at least 70%, preferably at least about 80%, and more preferably at least about 90%. A color rendering index (CRI) of at least about 80 is preferably achieved by at least some of the luminaires disclosed herein, with a CRI of at least about 88 being more preferred and at least about 90 being most preferred. Some lights exhibit a CRI of at least about 90, while maintaining a relatively high efficiency. Any desired particular output light distribution, such as a butterfly light distribution could be achieved, including up and down light distributions or just up or down distributions, etc.

Using a relatively small light source that emits in a broad (eg Lambertian) angular distribution (which is normally the case for LED based light sources), preserving the etendue, as is well understood in the art, requires an optical System with a large emission area to achieve a narrow (collimated) angular light distribution. In the case of parabolic reflectors, a large optic thus generally has to achieve high levels of collimation. In order to achieve a large emission area in a more compact design, the prior art relies on the use of Fresnel lenses that use refractive optical surfaces to align and collect the light. However, Fresnel lenses are generally planar in nature and therefore are not well suited to redirecting light at a wide angle emitted by the source, resulting in a loss of optical efficiency. In contrast, in the embodiments described herein, light is coupled into the optic, predominantly using TIR for redirection and collimation. This coupling allows the full range of angular emission from the source, including wide angle light, to be redirected and collimated, resulting in higher optical efficiency with a more compact form factor. An example of a waveguide with high efficiency in a compact form factor is disclosed in U.S. Pat. Patent Application No. 13 / 839,949 filed Mar. 15, 2013, entitled "Optical Waveguide and Lamp Including Same" (Cree Serial Number P1961US1).

In at least some of the present embodiments, the distribution and orientation of the light within the waveguide is better known and thus the light is controlled and extracted in a controlled manner. In standard optical waveguides, the light bounces back and forth through the waveguide. In the present embodiments, the light is extracted as much as possible over one pass through the waveguide to minimize losses.

In some embodiments, there may be a desire to control the light rays to collimate at least some of the light rays, but in the same or other embodiments, it may be desirable to control all or other of the light rays to increase their angular dispersion so that the light is not collimated. In some embodiments, there may be a desire to collimate on narrow areas, while in other cases there may be a desire to do exactly the opposite.

All references, including publications, patent applications and patents, are hereby incorporated by reference to the same extent as if the application were individually and specifically indicated as if they were listed in their entirety herein.

The use of the terms "a" and "one" and "the" and similar references in the context of a description of the embodiments is intended to cover both the singular and the plural, unless otherwise stated herein is given or can be clearly seen from the context. An indication of ranges of values made herein is merely intended to serve as an abbreviated method of individual reference to any discrete value falling within the range, unless otherwise noted, and each separate Value is built into the description as if it were specified here individually. All of the methods described herein may be performed in any suitable order, except as otherwise indicated herein or as otherwise clearly understood from context. The use of any and all examples or exemplary language (for example, "such") set forth herein is merely for the better understanding of the disclosure and does not limit the scope of the disclosure. No words in the description should be construed that way be that he indicates any element as essential to the practice of the disclosure.

Numerous modifications of the present disclosure will be apparent to those of ordinary skill in the art in light of the foregoing description. It should be understood that the illustrated embodiments are exemplary only and are not intended to be limiting on the scope of the disclosure.

Claims (32)

Luminaire comprising: an optical waveguide having a first surface and a second surface opposite to the first surface; a light source associated with the optical waveguide; wherein at least about 80% of light generated by the light source is directed by the waveguide into an illumination distribution emitted from the first surface of the optical waveguide. The luminaire of claim 1, wherein at least about 90% of the light is emitted from the first surface of the optical waveguide. A luminaire according to claim 1, wherein at least about 95% of the light is emitted from the first surface of the optical waveguide. Luminaire according to claim 3, wherein the optical waveguide has an optical efficiency of at least 90%. A luminaire according to claim 3, wherein the optical waveguide has an optical efficiency of at least 95%. The luminaire of claim 1, wherein the waveguide comprises a plurality of extraction features disposed on the first surface. The luminaire of claim 6, wherein each extraction feature comprises an outer surface extending between an opening adjacent the first surface of the waveguide and a base opposite the opening, and wherein the outer surface is undercut adjacent to the first surface of the waveguide. A luminaire according to claim 7, wherein the plurality of extraction features comprises a first extraction feature having a first height and a second extraction feature having a second height different from the first height. The luminaire of claim 7, wherein the plurality of extraction features comprises a first extraction feature having a first orifice diameter and a second extraction feature having a second orifice diameter different than the first orifice diameter. The luminaire of claim 7, wherein the plurality of extraction features comprises a first extraction feature having a first base diameter and a second extraction feature having a second base diameter different than the first base diameter. A luminaire according to claim 6, wherein the plurality of extraction features are arranged in a hexagonal field. Luminaire comprising: a waveguide having a first surface and a second surface opposite the first surface, the waveguide comprising an extraction feature disposed on the first surface; and a light source associated with the waveguide; wherein light emitted from the light source is directed by the waveguide into an illumination distribution emitted from the first surface of the waveguide; and wherein the waveguide is optically transparent such that the illumination distribution is visible along a line of sight through the waveguide extending from the second surface to the first surface. The luminaire of claim 12, wherein at least about 90% of the light generated by the light source is emitted from the first surface of the waveguide, and wherein the waveguide has an optical efficiency of at least 90%. A luminaire according to claim 12, wherein the waveguide exhibits a brightness of less than about 5% of the light generated by the light source, which is visible along the line of sight. The luminaire of claim 12, wherein the extraction feature has a curved shape extending between an opening adjacent the first surface and a base opposite the opening. A luminaire according to claim 15, wherein said curved shape has an outer surface determined by iteratively plotting dots using a differential equation. A luminaire according to claim 16, wherein the differential equation calculates that curvature of the outer surface which achieves a total internal reflection of light at the outer surface of the extraction feature. The luminaire of claim 17, wherein the differential equation calculates a slope, slope, of a point along the outer surface and comprises: Slope = - dh / dR = tan (+ α) where α represents a complementary angle of maximum incidence angle allowing for total internal reflection; wherein φ is defined by a light beam incident on the point with the coordinates (h, R + R ₀ ) relative to an edge of the opening opposite the point, and wherein φ is calculated in accordance with the following relationship:

where h is the distance from the first surface of the waveguide, R _{0 is} a radius of the aperture, and R is a distance from a centerline of the extraction feature to the point. Luminaire according to claim 15, wherein the curved shape has a height of between about 10 microns and about 500 microns. The fixture of claim 15, wherein the curved shape has a first portion adjacent to the opening and a second portion adjacent to the base. Luminaire according to claim 20, wherein the first portion has an outer surface which is undercut relative to the first surface of the waveguide. Luminaire according to claim 20, wherein the second portion has a cylindrical shape. Luminaire according to claim 20, wherein the second portion has a height of between about 10 microns and about 100 microns. Luminaire according to claim 12, wherein the waveguide and the extraction feature comprise the same material. Luminaire according to claim 12, further comprising an element, wherein the base of the extraction feature is arranged on the element. A luminaire according to claim 25, wherein said element is made of a material selected from the group consisting of a film, a glass, a polyester and an acrylic. A luminaire according to claim 12, wherein a bonding feature formed at the top of the aperture is displaced with the light emitting surface of the waveguide during connection of the extraction feature. Luminaire according to claim 12, wherein the luminaire generates an asymmetrical illumination distribution. Luminaire according to claim 12, wherein the luminaire has an overall efficiency of at least 90%. Luminaire comprising: a housing; an LED element disposed in the housing; a waveguide having a light emitting surface disposed in the housing adjacent to the LED element; and an extraction feature disposed on the light emission surface of the waveguide; wherein the extraction feature has a curved shape extending between an opening adjacent to the light emitting surface and a base opposite to the opening. The luminaire of claim 30, wherein the LED element is disposed in a first end of the housing, and wherein the waveguide extends out of a second end of the housing opposite to the first end. Luminaire according to claim 31, wherein the LED element is arranged along a coupling surface of the waveguide.

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