Waveguide with unidirectional illumination

Abstract

Luminaire (50), including: a case (64); an LED element (86) that is arranged in the housing (64); a waveguide (54) with a light-emitting surface (56) arranged in the housing (64) adjacent to the LED element (86); and an extraction feature (84) arranged on the light emission surface (56) of the waveguide (54); wherein the extraction feature (84) has a curved shape extending between an opening (100) adjacent to the light emission surface (56) and a base (102) opposite the opening (100), wherein a gap (106) is arranged between the light emission surface (56) of the waveguide (54) and the base (102) of the extraction feature (84), characterized in that the extraction feature (84) has a first section (112) adjacent to the opening (100) with a truncated, curved surface and an adjacent second section (114) with a cylindrical or conical shape adjacent to the base (102).

Description

[0001] The present application is a continuation of US patent application No. 14 / 472,078, filed on August 28, 2014, entitled “Waveguide Having Unidirectional Illuminance” (Cree file number P2289US1).

[0002] The present application claims priority from US Provisional Patent Application No. 61 / 922,017, filed on December 30, 2013, entitled “Optical Waveguide Bodies and Luminaires Utilizing Same” (Cree File No. P2143USO) and US Provisional Patent Application No. 62 / 020,866, filed on July 3, 2014, entitled “Luminaires Utilizing Edge Coupling” (Cree File No. P2289USO). The present application further comprises a continuation-in part of US patent application no. 13 / 839,949, filed on March 15, 2013, entitled “Optical Waveguide and Lamp Including Same” (Cree file no. P1961US1), and further comprises a continuation-in part of US patent application no. 13 / 840,563, filed on March 15, 2013, entitled “Optical Waveguide and Luminaire Incorporating Same” (Cree file no. P2025US1), and further comprises a continuation-in part of US patent application no. 13 / 938,877, filed on March 10, 2013.July 2013, entitled “Optical Waveguide and Luminaire Incorporating Same” (Cree file no. P2025US2), and further comprises a continuation-in part of US patent application no. 14 / 101,086, filed on December 9, 2013, entitled “Optical Waveguides and Luminaires Incorporating Same” (Cree file no. P2126US1), and further comprises a continuation-in part of US patent application no. 14 / 101,132, filed on December 9, 2013, entitled “Waveguide Bodies Including Redirection Features and Methods of Producing Same” (Cree file no. P2130US1), and further comprises a continuation-in part of US patent application no. 14 / 101,147, filed on December 9, 2013, entitled “Luminaires Using Waveguide Bodies and Optical Elements” (Cree file number P2131US1), and further includes a continuation-in part of US patent application no. 14 / 101,129, filed on 9.December 2013, entitled "Simplified Low Profile Module With Light Guide For Pendant, Surface Mount, Wall Mount and Stand Alone Luminaires" (Cree file no. P2141 US1), and further comprises a continuation-in part of US patent application no. 14 / 101,051, filed on December 9, 2013, entitled "Optical Waveguide and Lamp Including Same" (Cree file no. P2151 US1), and further comprises a continuation-in part of international patent application no. PCT / US14 / 13937, filed on January 30, 2014, entitled "Optical Waveguide Bodies and Luminaires Utilizing Same" (Cree file no. P2143WO), and further comprises a continuation-in part of international patent application no. PCT / US14 / 13931, filed on January 30, 2014, entitled “Optical Waveguides and Luminaires Incorporating Same” (Cree file number no.P2126WO), all in the possession of the applicant of the present application, the disclosures therein being incorporated herein by reference. This patent application incorporates by reference the concurrently pending US patent application No. 14 / 472,064, entitled “Luminaire with Selectable Luminous Intensity Pattern” (Cree file no. P2262US1), filed on August 28, 2014, and US patent application No. 14 / 472,035, entitled “Luminaires Utilizing Edge Coupling” (Cree file no. P2346US1), filed on August 28, 2014, both in the possession of the applicant of the present application.

[0003] The present application also claims priority from International Patent Application No. PCT / US14 / 13934, filed on January 30, 2014, entitled “Optical Waveguide and Luminaire Incorporating Same” (Cree File No. P2025WO); International Patent Application No. PCT / US14 / 13931, filed on January 30, 2014, entitled “Optical Waveguides and Luminaires Incorporating Same” (Cree File No. P2126WO); and International Patent Application No. PCT / US14 / 13840, filed on January 30, 2014, entitled “Simplified Low Profile Module with Light Guide for Pendant, Surface Mount, Wall Mount and Stand Alone Luminaires” (Cree File No. P2141WO). International Patent Application No. PCT / US14 / 13891, filed on January 30, 2014, entitled “Optical Waveguide and Lamp Including Same” (Cree File No. P2151WO); and International Patent Application No. PCT / US14 / 72860, filed on January 30, 2014.December 2014, entitled “Luminaires Utilizing Edge Coupling” (Cree file no. P2346W0); the International Patent Application no. PCT / US** / *****, entitled “Luminaire with Selectable Luminous Intensity Pattern” (Cree file no. P2262W0). AREA OF INVENTION

[0004] The subject of the application relates to a luminaire that uses optical waveguides for general lighting. BACKGROUND OF THE INVENTION

[0005] An optical waveguide mixes and directs 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) direct(s) light into the distribution element(s) and prepare the light so that it interacts with the subsequent components. The one or more distribution elements control how light passes through the waveguide and are independent of the waveguide geometry and material. The extraction element(s) determine how light is removed by controlling where and in which direction the light exits the waveguide.

[0006] When designing a coupling element, the main considerations are as follows: maximizing the efficiency of light transfer from the source into the waveguide; controlling the location of light injected into the waveguide; and controlling the angular distribution of the light within the waveguide. A waveguide coupling element may comprise one or more 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 array of lenses) positioned between the source and the waveguide coupling surface(s), one or more reflective or scattering surfaces surrounding the sources, and specific optical geometries formed within the waveguide coupling surfaces themselves.Proper design of the elements that make up the coupling system can provide control over the spatial and angular spreading of light within the waveguide (and thus how the light interacts with the extraction elements), maximize the coupling efficiency of light into the waveguide, and improve the mixing of light from different sources within the waveguide (which is particularly important when the color of the sources changes, either due to the design or as a result of normal bin-to-bin variation in the illumination components). The waveguide coupling system elements can use reflection, diffraction, total internal reflection, and surface or volume scattering to control the distribution of light injected into the waveguide.

[0007] To increase the coupling of light from a light source into a waveguide, it is desirable to maximize the number of light rays emitted by the source(s) that directly strike 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 reaching the waveguide coupling surface. Each such ray is thus subject to absorption at each reflection or scattering event, resulting in light loss and inefficiency. Furthermore, each ray striking the coupling surface has a portion that is reflected (a Fresnel reflection) and a portion that is transmitted into the waveguide.The percentage of light reflected is lowest when the beam strikes the coupling surface at an angle of incidence relative to the surface normal close to zero (i.e., approximately normal to the surface). The percentage reflected is highest when the beam strikes at an angle relative to the surface that is normal to the coupling surface (i.e., approximately parallel to the surface). To increase efficiency, coupling the light into the waveguide body minimizes light absorption during reflection or scattering events, as well as Fresnel reflection at the coupling surface.

[0008] In a conventional coupling, a light source, typically emitting 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 is limited as a result of the wide angular distribution of the source and the relatively small fixed angle represented by the adjacent planar surface. To increase the amount of light incident directly on the coupling surface, a bare component, such as the Cree ML series or MK series (manufactured and sold by Cree Inc. of Durham, NC, the applicant of the present application), can be used. A bare component is a light source that does not include primary optics, a lens, or discrete coupling optics formed on an LED chip.The flat emission surface of the LED chip can be positioned in close proximity to the coupling surface of the waveguide. While this arrangement helps ensure that a large portion of the emitted light directly impacts the waveguide, the overall system efficiency generally decreases, as bare components are typically less efficient than components with primary lenses that allow light extraction from the component, thus improving overall efficiency.

[0009] As described above, the use of higher-efficiency LED elements with conventional (for example, predominantly hemispherical or cubic) primary optical arrangements results in a limited amount of light directly impacting the waveguide coupling surface. Such a light source (or sources) is (are) 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 reducing the overall system efficiency due to losses occurring with each reflection event. In some luminaires, the waveguide (or waveguides) may have coupling surfaces specifically shaped to maximize the amount of light absorbed at the coupling surfaces.Alternatively, each LED can be positioned in a cylindrical coupling cavity inside the waveguide, and a reflective cap with a conical plug diverter can be placed at the opposite end of the coupling cavity.

[0010] Once light has been coupled into the waveguide, it must be guided and conditioned to the extraction points. The simplest example is a fiber optic cable, which is designed to transport light from one end of the cable to the other 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 internal reflection, light propagating through a waveguide is reflected back into the waveguide from an outer surface, 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 strike a refractive index transition surface at a certain angle less than an angle measured with respect to a line normal to the surface point where the light rays are incident (or equivalently, until the light rays exceed an angle measured with respect to a line tangential to the surface point where the light rays are incident) and the light rays escape.

[0011] For an extraction element to extract light from the waveguide, the light must first contact the feature encompassing the element. By appropriately shaping the waveguide surfaces, the light flow across the extraction feature(s) can be controlled, thus influencing 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 (illumination), the resulting angular distribution of the emitted light (brightness), and the optical efficiency of the system.

[0012] When designing waveguide / extractor lighting systems, an 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 troffer (ceiling) lighting, the light source or luminaire is typically mounted on or near the ceiling and provides illumination for the walls and floor of a room. In this case, it is desirable for the luminaire to provide light in usable directions (for example, towards the surfaces to be illuminated), and the viewer or person present in the room will typically be able to look directly at the light-emitting surfaces. Therefore, glare can become a concern if too much light is provided from a sufficiently small emission area at a particular viewing angle.While low luminaire costs and architectural designs may necessitate smaller light-emitting surfaces, the requirement to limit glare will typically impose a lower limit on the luminaire size and / or require architectural features, such as a recessed light source, to achieve the desired level of illumination. Alternatively, conventional task or workplace lighting provides 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 (for example, a ring of lights around a microscope lens or a head light positioned above or to the side of the viewer's head). The light from such workplace lighting is angled toward the viewer's line of sight, but not in line with their gaze.This staggered lighting creates shadows and prevents a viewer from seeing certain surfaces, such as the inside of narrow openings. Furthermore, conventional work lighting typically requires a large amount of light to be emitted from a necessarily small source, making the light source extremely visible and producing bright spots or glare along the surface of the work light, as well as reflections of the work light from bright or reflective work surfaces.

[0013] Hulse US patent US 5,812,714 A discloses a waveguide bending element configured to change the direction of light from a first direction to a second direction. The waveguide bending element includes a collector element that gathers light emitted from a light source and directs the light onto an input surface of the waveguide bending element. Light entering the bent element is internally reflected along an outer surface and exits the element at an output surface. The outer surface comprises chamfered angled surfaces or a curved surface oriented such that most of the light entering the bending element is internally reflected before reaching the output surface. Parker et al.US Patent 5,613,751 A discloses a light-emitting field arrangement comprising a transparent light-emitting field that includes a light-intake surface, a light-transmitting region, and one or more light sources. The light sources are preferably embedded or bonded within the light-transmitting region to eliminate any air gaps, thus reducing light loss and maximizing the emitted light. The light-transmitting region may include reflective and / or diffracting surfaces around and behind each light source to reflect and / or diffract and focus the light more efficiently through the light-transmitting region into the light-intake surface of the light-emitting field. A pattern of light extraction deformations or any modification in the shape or geometry of the field surface and / or 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 can break up the light rays so that the internal reflection angle of some of the light rays will be large enough to cause the light rays to either be emitted out of the field or reflected back through the field and emitted from the other side.

[0014] Shipman discloses in US patent US 3,532,871 A a combination graduated light reflector with two light sources, each of which, when illuminated, develops or generates light that is directed onto a polished projection surface. The light is reflected onto a conical reflector. The light is then reflected transversely into a main body and strikes prisms that direct the light away from the main body.

[0015] Simon discloses in US patent US 5,897,201 A various embodiments of an architectural lighting system that distributes radially collimated light. A quasi-point source emits light that is collimated in a radially outward direction, and deflection devices of the distribution optics direct the collimated light out of the optics.

[0016] Kelly et al., in US patent US 8,430,548 A, describe light sources that utilize a variety of light sources, such as an incandescent bulb, a fluorescent tube, and multiple LEDs. A volumetric diffuser controls the uniformity of spatial brightness and the angular dispersion of the light from the light source. The volumetric diffuser comprises one or more areas of volumetric light-scattering particles. The volumetric diffuser can be used in conjunction with a waveguide to extract light.

[0017] Dau et al. disclose in US patent US 8,506,112 B1 lighting devices with multiple light-emitting elements, such as LEDs, arranged in a line. A collimating optical element receives light emitted by the LEDs, and a light guide directs the collimated light from the optical element to an optical extractor, which extracts the light.

[0018] ALP Lighting Components, Inc. of Niles, Illinois, manufactures a wedge-shaped waveguide with a thick end, a narrow end, and two main faces in between. Pyramidal extraction features (objects) are formed on both main faces. The wedge waveguide is used as an extraction shield, with the thick end of the shield positioned adjacent to a ceiling and the narrow end extending downward. Light entering the waveguide at the thick end is directed downward and away from the waveguide by the pyramidal extraction features.

[0019] Low-profile, LED-based luminaires have recently been developed (for example, General Electric's ET-Series Panel Troffers), and these use a chain of LED components directed towards the edge of a waveguide element (a so-called "edge-illuminated" approach). However, such luminaires typically suffer from the disadvantage of low efficiency, resulting from the inherent losses in coupling light emitted from a predominantly Lambertian source, such as an LED component, to the narrow edge of a waveguide plane.

[0020] Beeson et al., in US Patent US 5,396,350 A, describe a backlighting device used for flat-panel electronic displays. The device comprises a slab waveguide that receives light from a light source located adjacent to one of its side faces, and an array of microprisms attached to one end face of the waveguide. Each microprism has one side face 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.

[0021] Zimmermann et al. disclose in US Patent US 5,598,281 A a backlighting arrangement for electro-optical displays. Light emitted from a light source located within a reflector propagates through an array of apertures and is collected or collimated by an array of wedge-shaped or tapered optical elements aligned with the array of apertures. Microlenses are arranged adjacent to the optical elements to further collect or collimate the light. The surfaces of the optical elements are planar or parabolic in shape.

[0022] Zimmermann et al. describe in US Patent US 5,428,468 A an optical illumination system for applications requiring essentially collimated light. The system comprises a waveguide that receives light from one edge. An array of microprisms is mounted on an end face of the waveguide. Each microprism has at least two side walls inclined at an angle to the normal of the waveguide surface. An array of microlenses can be arranged on top of the array of microprisms to further collimate the light.

[0023] Steiner et al. disclose in US Patent US 5,949,933 A an optical illumination system for collimating light. The system comprises a waveguide that receives light from one edge thereof and an array of lens-shaped microprisms mounted on an end face of the waveguide. Each microprism has a light-intake surface that is optically coupled to the waveguide and a light-output surface opposite the input surface. The light-intake surface includes a number of tapered grooves perpendicular to the length of the lens-shaped microprisms. The system also includes an array of microlenses for further collimating the light.

[0024] Hou et al., in US Patent 5,839,823 A, describe an illumination system with a light source located adjacent to or within a reflector. A light-aligning arrangement with at least one microprism supported on a base wall is positioned adjacent to the light source and opposite the reflector. The microprism can be multifaceted, curved, or multifaceted. A lens array can be arranged on the opposite side of the base wall.

[0025] Kuper et al. disclose in US Patent US 5,761,355 A a light-aligning optical structure comprising a waveguide to which a variety of prisms are attached. Light deflected by the prisms is restricted to a range of angles. The side face(s) of the prisms can be planar or curved. An array of lenses can be used to spread the light output of the prisms to a wider distribution angle.

[0026] US 8,033,706 B1 and US 2007 / 0279,933 A1 concern edge-lit backlights or illuminations. US 2010 / 0302,135 A1 concerns a backlight for an LCD with a refractive waveguide. WO01 / 02,772 A1 concerns a display assembly with a waveguide and extraction features. US 8,031,293 B2 concerns a backlight with multiple light sources and a waveguide. US 2010 / 0288,614 A1 concerns waveguides with extraction features. SUMMARY

[0027] According to one aspect of claim 1, a luminaire comprises a housing, an LED element arranged within the housing, and a waveguide with a light-emitting surface arranged in the housing adjacent to the LED element. An extraction feature is arranged on the light-emitting surface of the waveguide. The extraction feature has a curved shape extending between an opening adjacent to the light-emitting surface and a base opposite the opening.

[0028] Other aspects and advantages will become clearer from a closer look at the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings show: Fig. 1 an isometric view of an embodiment of a luminaire in a room; Fig. 2 an isometric front view of the light fixture Fig. 1; Fig. 2A an exploded view of a housing of the luminaire Fig. 1; Fig. 3 a rear isometric view of the light fixture Fig. 1; Fig. 4 a broken front elevation view of the light of the Fig. 1; Fig. 5 a cross-sectional view of the light fixture Fig. 1, generally along the intersection lines 5-5 of the Fig. 2; Fig. 6 An enlarged side elevation view of a waveguide of the luminaire. Fig. 1; Fig. 7 A broken isometric view of an embodiment of extraction features located in the luminaire of the Fig. 1. can be used; Fig. 8 a side elevation view of the extraction features of the Fig. 7; Fig. 9A and Fig. 96 a side elevation view or a top view of the extraction features of the Fig. 7 before application to a waveguide; Fig. 10A-10C a side elevation view, a top view and a side elevation view of each of the extraction features of the Fig. 7 after application to a waveguide; Fig. 11A-11C an isometric view, a side elevation view or top view of a further embodiment of an extraction feature before application to a waveguide; Fig. 12 an enlarged side elevation view of a waveguide of the luminaire of the Fig. 1; Fig. 13 an enlarged side elevation view of a waveguide of another embodiment of a luminaire; and Fig. 14 a graphical representation showing a light distribution as a function of the extraction feature height of the luminaire of the Fig. 1 represents. DETAILED DESCRIPTION

[0030] Referring to Fig. Figure 1 shows a luminaire 50 which provides an illumination distribution 52 with concealed illumination 53. The luminaire 50 comprises an optical waveguide 54 with a first surface 56 and a second surface 58, which is opposite the first surface 56. At least 80%, preferably at least 90%, and more preferably at least 95% of the light emitted by a light source 60 ( Fig. 4) is generated and is directed by the waveguide 54 into the illumination distribution 52, which is emitted from the first surface or light-emitting surface 56 of the waveguide 54. Furthermore, the illumination distribution 52 is visible through the waveguide 54 along a line of sight 62 extending from the second surface 58 to the first surface 56. The waveguide 54 exhibits illumination 53 from the second surface 58 along the line of sight 62, which is less than 20%, preferably less than approximately 10%, and more preferably less than approximately 5% of the total brightness of the luminaire. In general, “hidden” or “concealed” illumination refers to the visibility of the illumination distribution 52 along the line of sight 62 through the waveguide 54, while the illumination 53 from the second surface 58 along the line of sight 62 during use (i.e., when connected to the light source 60 ( Fig. 4) energy is supplied) is minimized. The line of sight 62 can be perpendicular or angled to the first and second surfaces 56, 58 of the waveguide 54. Furthermore, simulations have shown that the embodiments described here provide an optical efficiency of at least 90° / 0, and in particular at least 95%.

[0031] As in Fig. 2. As can be seen, the waveguide 54 of the luminaire 50 extends from a housing or enclosure 64, which has a first part 66a and a second part 66b. In the illustrated embodiment, the first and second parts 66a, 66b are identical in shape and are oriented in opposite directions during use in order to be coupled to each other. As shown in Fig. As can be seen in Figure 2A, each part 66a, 66b comprises a circumferential edge 70a, 70b that extends inwards along the first, second, and third surfaces 72a, 72b, 74a, 74b', respectively 76a, 76b. The first and second parts 66a, 66b are oriented relative to each other such that the first and third surfaces 72a, 76b and 72b, 76a align with each other. Two screw holes 78 are formed along the third surfaces 76a, 76b, and two recesses 80a, 80b are formed along the first surface 72a, 72b to align with the two screw holes 78a, 78b of the corresponding part. Every second surface 74a, 74b comprises a raised section 74a-1, 74b-1 and a lowered section 74a-2, 74b-2, which correspond to the raised and lowered sections of the corresponding second surface 74a, 74b. The fourth surfaces 82a ( Fig. 4), 82b ( Fig. The two parts 66a and 66b are spaced apart to allow the waveguide 54 to extend from them. A recess 83 is formed adjacent to the second surfaces 74a, 74b of the first and second parts 66a, 66b, and a light source element 83a is arranged therein. The first and second parts 66a, 66b are held together by fasteners 85, although any suitable fastening device may be used. An illuminated surface of an object 87 is seen through the waveguide 54 and illuminated by the light source 50.

[0032] Referring to Fig. Extraction features 84 are arranged on the first side 56 of the waveguide 54. In some embodiments, the extraction features 84 are not visible to observers in the room. In other embodiments, the extraction features are arranged in a regular array, such as a tightly packed hexagonal array. In still other embodiments, the extraction features are arranged in a specific pattern (density pattern) to improve optical efficiency, uniformity of illumination, or the provision of a desired visual effect, image, or illumination pattern (logo, picture, graphic, etc.).

[0033] Fig. Figure 4 shows LED elements 86 arranged in a first end 88 of the housing 64 adjacent to the second surface 74a of the first part 66a. The waveguide 54 extends from a second end 90 of the housing 64 opposite the first end 88, which is bordered by the fourth surfaces 82a, 82b ( Fig. 2A) of the first and second parts 66a, 66b ( Fig. 2A). In the illustrated embodiment, the waveguide 54 is illuminated along a coupling surface 92 by the plurality of LED elements 86 at its edge. The LED elements 86 are mounted on a printed circuit board 94, which is mounted on the light source element 83a and spaced apart from the coupling surface 92 of the waveguide 54. 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 can comprise more than one waveguide and can employ coupling with internal illumination, coupling at multiple edges, or a combination thereof. The type of coupling can influence the angular and spatial distribution of the light within the waveguide, which in turn can affect the extraction efficiency, illumination, and brightness.

[0034] Various types of LED elements can be used, including LED packages with primary optics assemblies, as well as bare LED chips. Each LED element or module 86 can be a single white LED or an LED of another color, or it can each comprise several LED elements mounted either separately or together on a single substrate or package to form a module, including, for example, at least one phosphor-coated 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 produced, each LED element or module 86, or a plurality of such elements or modules, can 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 can be produced using other LED combinations, as is known in the technical field. The luminaire can include LEDs 65 of 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 can include a plurality of groups of LEDs 65, each group potentially comprising LEDs 65 with different colors and / or color temperatures. The groups of LEDs 65 can be separated by dividers, as described in US Patent Application No. ** / ***,***, filed on 28.August 2014, entitled “Luminaire Utilizing Multiple Edge Coupling” (Cree file number P2346US1), which is incorporated herein by reference, wherein 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 necessary or desirable. Furthermore, in one embodiment, the light source comprises any LED, for example, an MT-G LED incorporating TrueWhite® LED technology, or as disclosed in US patent application number 13 / 649,067, filed on August 10, 2014.The LED package with multiple element light source and encapsulant having planar surfaces, as developed and manufactured by Cree Inc., the applicant in the present application, was filed in October 2012 by Lowes et al. (Cree file number P1912US 1-7), the disclosure of which is incorporated herein by reference. If desired, a side-emitting LED disclosed in US patent number 8,541,795, the disclosure of which is incorporated herein by reference, may be used. In some embodiments, each LED element or module 86 may comprise one or more LED elements arranged vertically within the coupling cavity.In any of the embodiments disclosed herein, the LED element(s) or module(s) 86 may have a Lambertian or nearly Lambertian light distribution, although each may have a directional emission distribution (for example, a side-emitting distribution), as required or desired. More generally, any Lambertian, nearly Lambertian, symmetrical, wide-angle, one-sided, or asymmetrical beam pattern LED(s) may be used for the light source.

[0035] Referring to the Fig. 5-8 Light is predominantly extracted from the first surface 56 of the waveguide 54 by the extraction features 84 attached or bonded to it. Each extraction feature 84 comprises a body 96 ( Fig. 7) with a curved shape 98 extending between an opening 100 adjacent to the first surface of the waveguide 54 and a base 102 opposite the opening 100. The opening 100 and the base 102 may be parallel to each other or may be arranged at an angle to each other. As shown in Fig. As can be seen in Figure 6, the curved shape 98 comprises an outer surface 104 that is undercut relative to the first surface 96 of the waveguide 54. The outer surface 104 can be planar, curved, planar (approximately curved), or a combination thereof. The profile of the outer surface can be symmetrical (for example, as in the case of a hemisphere) or asymmetrical (for example, as in the case of an ellipse or another combination of shapes). The extraction features and / or the waveguide can be made of acrylic, an acrylic UV-curable resin, silicone, polycarbonate, glass, or any other suitable material(s) and combinations thereof, possibly in a layered arrangement to achieve a desired effect.

[0036] In the Fig. 6 to Fig. In the embodiment shown in Figure 8, the extraction features 84 can be formed on an element 108, which is then bonded or otherwise optically connected to the first surface 56 of the waveguide 54. The element 108 can be a film, glass, acrylic, or any suitable optically transparent material. For example, the element 108 can comprise an acrylic, polyethylene terephthalate (PET), or polyester-based film (for example, under the trademark "Mylar") or a film of any other suitable material on which extraction features are formed or replicated. The extraction features 84 can comprise a suitable optical material, such as acrylic, acrylic-based resins, polycarbonate, glass, or other materials with suitable optical and structural properties.The film can be produced using any of a variety of techniques typically employed in the formation of micro-optical films, including die-cutting, photolithography, grayscale lithography, micro-replication, injection molding / compression forming, reactive ion heating, chemical die-cutting, casting, or drum roll transfer. Other manufacturing methods include casting an acrylic-based UV-curing resin or silicone material onto a support film, which is then cured to form extraction features.The resulting extractor film or extractor layer can be laminated or otherwise attached to the first surface 56 of the waveguide 54, either directly or with one or more intermediate layers, using a variety of joining methods, including ultrasonic joining, laser joining, adhesive joining, pressure-sensitive adhesive joining, chemical welding and thermal bonding.

[0037] In some embodiments, the extraction features 84 can be arranged on the waveguide 54 without an element 108. For example, the extraction features 84 can be fabricated directly on the first surface 56 of the waveguide 54 using an intermediate layer for pattern generation, as described in U.S. Patent No. 8,564,004, granted on October 22, 2013, entitled “Complex Primary Optics with Intermediate Elements” by Tarsa et al. (Cree file no. P1445), which is incorporated herein by reference. Using this fabrication method, the extraction features 84 are optically connected to the waveguide 54 without the need for the substrate 108.The pattern-generating layer can be produced using any process, such as forming, injection molding, compression molding, casting, stencil printing, 3D printing, photolithography, deposition, and the like. Specifically, the pattern-generating layer is formed on the first surface 56 of the waveguide 54 and includes holes or openings where the waveguide 54 is exposed. The openings of the pattern-generating layer correspond to the locations where the extraction features 84 are to be formed on the waveguide 54. In some embodiments, a mold is then applied over the pattern-generating layer and the first surface 56 of the waveguide 54. The mold includes voids aligned with the openings of the pattern-generating layer to define cavities. The cavities are filled with the extraction feature material 84.In other embodiments, the extraction feature material 84 is applied to the openings of the pattern-generating layer before the mold is placed on the pattern-generating layer. In each case, the extraction feature material 84 is then at least partially cured, and the mold is removed. The pattern-generating layer material can comprise polyvinyl alcohol, poly(methyl methacrylate) (PMMA), one or more photoresist materials, or other suitable materials. The pattern-generating layer can be removed by water rinsing, heat, evaporation, machining, developer and solvents, chemical etching / solvent etching, plasma etching, or any process that does not attack the material of the waveguide 54 and / or the extraction features 84.Alternatively, the waveguide 54, the extraction features 84 and / or the element 108 can be bonded together by one or more additional layers, such as an adhesive layer or a pressure-sensitive adhesive film.

[0038] The optical efficiency, directivity, brightness, and illumination of the waveguide-supported luminaire depend sensitively on the specific geometry and arrangement of the extraction features 84. One class of extraction feature geometries that is particularly useful for a range of lighting applications includes a roughly “spherical” profile, as shown in Fig. Figures 11A-11C illustrate this profile, which consists of a truncated curved surface, such as a truncated hemisphere with an adjacent cylindrical or conical base. This particular geometry provides a high degree of directional characteristic, as well as a range of possible illumination distributions, which can be achieved by changing the height to which the curved surface is truncated. Referring to Fig. In 8, the section height H1 of the extraction feature 84 corresponds to a gap 106 between the first surface 56 of the waveguide 54 and the base 102 of the extraction feature 84. In some embodiments, the section height H1 is (resulting in a nearly hemispherical upper extractor section with a small flat surface at the apex), and light is extracted predominantly perpendicularly from the first surface 56 of the waveguide 54 to form a "spot light" distribution. In other embodiments, light can be extracted by changing the height H1 to form a Lambertian distribution or into a "split" distribution, in which light is emitted predominantly in one direction more parallel to the waveguide 54. A change in the dimension of the gap 106 results in a change in the illumination distribution 52, as described in US Patent Application No. ** / ***,***, filed on 28.August 2014, entitled “Luminaire with Selectable Luminous Intensity Pattern” by Tarsa et al. (Cree patent no. P2262US1). In some embodiments, the gap can be in a range of approximately 10 pm to approximately 590 pm, preferably approximately 100 pm to approximately 550 pm. In the case of a purely hemispherical extraction feature 84 with no cylindrical or conical base, the gap 106 can be in a range of 95% to 5% of the radius of the hemisphere, preferably 80% to 20% of the radius of the hemisphere. By adding a conical base to the hemisphere, as in . Fig. As shown in Figure 11, the directional characteristic of the emitted light can be further increased. As shown in Fig. As shown in Figure 14, the luminaire 50 produces extraction characteristics 84, as shown in Figure 14. Fig. 11 A, Fig. 11B and Fig. Figure 11C, which are described below, shows a luminance pattern or distribution that changes with feature height H1 or slit 106. The in Fig. The luminous flux distributions shown in Figure 14 assume that the extraction features 84 all have essentially the same shape. As in Fig. As can be seen in Figure 14, the luminance pattern changes from an asymmetrical distribution at feature heights H1 of approximately 170 pm to a working light or "spot light" distribution at a feature height of approximately 560 pm. In this case, the asymmetry with respect to the vertical axis in the illumination distribution representation refers to the positioning of the source along one edge of the waveguide. A more symmetrical pattern (for example, mirrored about the vertical axis in the representation) would result from illuminating the waveguide from two opposite edges. In general, the variations in illumination arise from variations in the optical coupling surface and the extractor aperture area between the extraction features 84 and the waveguide 54, just as the cross-sectional dimensions of the transition between features 84 and the waveguide change with the height H1 of the extraction feature (the clipping point).

[0039] Referring to Fig. 8, 9A, 9B, 10A, 10B and 11A-11C, the addition of a cylindrical or conical extension to the base of the hemisphere can increase the directivity or directional characteristic of the emitted light, while a simple truncated hemispherical extractor shape can provide a range of desirable illumination distributions. This directional characteristic (i.e., the portion of the light emitted from the first side 56 of the waveguide relative to the portion of the light emitted from the second side 58) is important for realizing luminaires with concealed lighting. In the example shown in Fig. 9A and Fig. As shown in Figure 9B, the extraction feature 84 comprises 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 first section 112 need not be hemispherical, and the second part 114 or second section 114 may be cylindrical, conical, or curved, as desired. The first section 112 may have a height in the range of approximately 5 pm to approximately 2 mm. The second section 114 may have a height in the range of approximately 5 pm to approximately 2 mm, although some embodiments may omit a second section 114. The shapes 112 and 114 may be circumferentially formed such that the cross-section is transverse to a central axis 118 ( Fig. 9A) over the entire height H1 ( Fig. 8) of the extraction feature 84 is circular. Alternatively, the shapes 112 and 114 can have non-circular cross-sections (for example, elliptical or faceted). In some embodiments, the base diameter db of the extraction feature 84 can be approximately twice the height H1.

[0040] In other embodiments, the first section or part 112 can be designed to redirect incident light downwards via total internal reflection (TIR). A form of the 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 internal reflection, and, based on the calculated slope, further calculating the required incremental radial step Ar corresponding to a predetermined incremental height change Δh, moving to the 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 can be constructed using geometric and / or differential equations, possibly in combination with other curved, planar or piecewise linear surfaces.

[0041] An example of the aforementioned interactive process involves using equations 1 and 2, given below, which are entered into an optimization routine such as Microsoft Excel® Solver. In general, a profile of the extraction feature 84 is defined by calculating a series of slopes dh / dR at incremental points 202a, 202b,...202N along an outer surface 116 of the first section 112 of the extraction feature 84. The outer surface 116 is then rotated about the central axis 118 to define the extraction feature 84. φ=ArcTan(hR+Ro) Slope=dhdR=tan(φ+α)

[0042] (Slope = gradient). In equation 1, the acute angle φ of a ray of light striking a given point, for example 202d, on the outer surface 116 is determined. As in Fig. As can be seen in Figure 10C, the acute angle φ is defined by a light ray 204 entering the aperture 100 at an edge 206 opposite the point 202d and is measured relative to a surface normal 208 of the aperture 100. The angle φ is calculated based on the coordinates of point 202d relative to the point where the light ray 204 enters the extraction feature 84 at the edge 206 of the aperture 100. In particular, point 202d has a Y-coordinate value h relative to the respective waveguide surface 56 and an X-coordinate value R0 + R, where R0 is a distance from the edge 206 to the central axis 118 (i.e., an aperture radius) and R is a distance from the central axis 118 to point 202d.

[0043] Using equations 2, the slope dh / dR at point 202d along the outer surface 116 is then calculated. Equation 2 ensures that the resulting angle of incidence δ to a surface normal 210 at point 202d does not exceed the critical angle Θ relative to the surface normal 210. As in Fig. As shown in Figure 10C, the angle α is complementary to the critical angle Θ. In the example shown, the resulting angle of incidence δ of the light ray 204 is approximately the same as or larger than the critical angle Θ, so that the light ray 204 is totally reflected by the outer surface 116 of the extraction feature 84 and emitted through the base 102 thereof.

[0044] Once the slope dh / dR for point 202d is calculated, the angle φ for the next point 202e is calculated using equation 1 with incremental changes Δh, ΔR along the x- and y-coordinates h, R. The slope dh / dR for point 200e is then determined using equation 2, and the process is repeated until a known parameter is satisfied, for example, once the vertical distance h equals the height F ( Fig. 10A) of the first section 112, or in some cases the total height F + G ( Fig. 10A) of extraction feature 84 is reached. The incremental change Δh can be in a range of approximately 1 nm to approximately 1 pm or can be a fraction, such as 1 / 50th of the total height F + G ( Fig. 10A) of extraction feature 84.

[0045] In some embodiments, equation 2 can be implemented with a conditional test to specify an upper bound for the slope dh / dR. This upper bound can then be used instead of the calculated slope, as desired. For example, with reference to Fig. 10C, the upper limit is specified as angle β, which is defined by an outer surface 122 of the second section 114 relative to the base 102. Once the calculated slope dh / dR of points 202 along the outer surface 116 of the first section 112 reaches the upper limit of angle 13, each slope dh / dR for the subsequent points 202 along the outer surface 122 of the second section 114 is constant and equal to β, in order to form the conical shape.

[0046] In some embodiments, the optimization routine can calculate the opening radius R0 for a preferred area ratio (i.e., ratio of the opening area to the base area) 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 minimum angle (φ min , defined by the acute angle φ of a light beam 212 incident on point 204 on the outer surface 132 at the base 122 of the extraction feature 116'. Other user-defined conditions can be specified as desired. In one embodiment, the outer surfaces 124, 132, constructed in accordance with the above description, result in the extraction of over 95% of the light from the first surfaces 62a, 64a of the waveguide 42.

[0047] In the Fig. 7 and Fig. In the exemplary embodiment shown in Figure 8, the plurality of extraction features 84 can be formed in a hexagonal field pattern on top of the element 108. Other patterns can be used to create a desired illumination distribution. The extraction features 84 can be irregularly spaced, or some can be regularly spaced and others irregularly spaced, etc. The thickness T1 of the element 108 can be in a range from 10 pm to 5 mm, preferably from 250 pm to 2 mm. The center-to-center distance D1 between adjacent extraction features 84 can be less than twice the feature radius (for example, overlapping features) up to 10 mm, preferably from twice the feature radius up to 5 mm. The thickness T1 and the distance D1 can be constant or can vary over the first surface 56 of the waveguide 54.The shape, size, and density of extraction features 84 can vary across 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 exhibiting differently shaped extraction features 84 can be bound to the waveguide 54 to create an asymmetric illumination distribution. The aperture diameters d. a , the base diameters d bThe heights H of the extraction features 84 can all be the same or different and can vary across the surface 56 of the waveguide 54 to produce different illumination patterns as desired. Furthermore, it may be desirable to fabricate different roughness grades or specific optical features, such as a second set or array of geometric features on an outer surface 110 of the element 108, to further control the brightness and illumination distributions. In other embodiments, the extraction features 84 can be positioned to extract brightness or illumination from both the first and second surfaces 56, 58.

[0048] Fig. 9A and Fig. Figure 9B illustrates the body 96 of the extraction feature 84 in front of a bond on the first surface 56 of the waveguide 54. The first outer surface 116 of the first section 112 is rotated about a central axis 118. The curvature of the first section 112 of the extraction feature 84 is designed to minimize the amount of light reflected back into the waveguide 54 either directly from the extraction feature 84 or indirectly from an adjacent section 120 ( Fig. 7) of element 108 is redirected between extraction features 84. Such minimization leads to a high extraction efficiency from the first surface 56 of the waveguide 54 (a high directional characteristic). In the illustrated embodiment, the curved shape is defined by equations 1 and 2.

[0049] A second outer surface 122 of the second section 114 has a conical shape forming an angle β with the base 102. The angle β can be in a range of 1° to 90°, preferably 60° to 90°. Furthermore, the body 96 can include a bonding feature 124 formed at the top of the opening 100 to enable or facilitate bonding of the extraction feature to the waveguide surface 56. The actual geometry of the bonding feature 124 can vary depending on the specific bonding approach used. For example, the bonding feature 124 can be convex (as in Fig. (9A shown), in order 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 design of the bonding feature 124 can also be such that the displacement or misalignment of the adhesive during bonding is minimized, thereby minimizing “stringing” of the displaced adhesive along the first and second sections 112, 114, where it could interfere with the optical function of these surfaces. In general, it is intended that part or all of the bonding feature 124 becomes optically inactive after the bonding process, so that it has a minimal effect on the resulting light distributions and efficiency. A similar bonding feature 124 is associated with the extractor geometry of the Fig. 11 shown. In an alternative embodiment, the bond feature 124 can comprise an adhesive material which serves to bond the extraction feature to the first surface 56 of the waveguide 54.

[0050] Fig. 10A and Fig. Figure 10B illustrates extraction feature 84 of the Fig. 9A and Fig. 9B, as it is attached to the first surface of the waveguide. Exemplary dimensions of the extraction feature of the Fig. 9A, Fig. 9B, Fig. 10A and Fig. 10B are specified below. In one embodiment, a luminaire with a plurality of extraction features extracts the Fig. 10A and Fig. 10B approximately 97% of the brightness 52 from the first surface and approximately 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 Grad Fig. 10A F 13.95 µm G 14.050 µm H 53.26 µm J 26.716 µm β 70 Grad

[0051] The Fig. Figures 11A-11C illustrate another embodiment of an extraction feature 184. The first section 112 of the body 96 has a hemispherical shape, although other geometries, such as a parabolic shape, freeform curves, planar and / or piecewise linear shapes, can be used to produce an illumination 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 Fig. 9A and Fig. 9B, the bond feature 124 is formed on the opening 100 to enable bonding of the first surface 56 to the waveguide 54. Exemplary dimensions of the extraction feature of the Fig. 11A-11C are listed in Table 3. In another embodiment, a luminaire with a variety of extraction features extracts the Fig. 11A-11C approximately 94% of the brightness 52 from the first surface and approximately 6° / 0 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 Krümmungsradius Θ 89 Grad

[0052] In further embodiments, the extraction features 84 can have an asymmetrical shape. For example, the first section 112 of the extraction feature 84 can be hemispherical and the base 102 can be elliptical, so that the feature 84 appears as a truncated hemisphere when viewed from any cross-section, but as an ellipse or an elongated circle when viewed from above. Such an asymmetrical geometry would result in an asymmetrical illumination pattern, which may be desirable for certain applications, such as street lighting. Furthermore, the extraction features 84, with an asymmetrical cross-section along the height H1 (i.e., coplanar to the central axis 118), can direct light in specific directions or quadrants below the luminaire.Extraction features 84 with segmented cross-sections and top profiles consisting of a combination of curved and linear surfaces (such as an extractor that appears as a truncated hemisphere from the side but as a star shape or faceted shape from above) can be used for specific lighting applications requiring a very unique and defined light distribution (for example, stage lighting, architectural lighting, or side lighting). Finally, extraction features that have a generally conical or parabolic shape (symmetrical or asymmetrical, truncated or not) can produce better collimated light beams in specific directions (for example, for a direct / indirect pendant light, downward lighting, etc.).

[0053] The extraction characteristics 84, which are in Fig. The features shown in Figures 6-11C, referred to here as "extraction features with openings," offer significant advantages in terms of controlling the light distribution, efficiency, and directional characteristics. As shown in Figures 6-11C, these features provide significant advantages in terms of controlling the light distribution, efficiency, and directionality. Fig. As shown in Figure 12, light extracted from the waveguide first enters the extraction features 84 through the openings 100 located on the light-emitting surface 56 of the waveguide 54. Light rays only reach the opening 100 after undergoing total internal reflection from another surface 58 of the waveguide 54 opposite the light-emitting surface 56. In contrast, conventional (non-scattering) extraction features, such as steps, hemispherical bumps, or depressions formed directly on the waveguide surface, generally result in optical surfaces that must interact with and control light incident from both surfaces 56 and 58 of the waveguide 54.In other words, light generally strikes the surfaces of such conventional extraction features after having been totally reflected from the wider surface and also totally reflected from the area immediately surrounding the depression. Because the optical surfaces of the extractor must handle light incident from essentially opposite directions, it is difficult to control illumination distributions over a range of illumination patterns with high extraction efficiency and high directivity (for example, from a single surface).

[0054] While the use of the extraction feature 84, which is provided with one or more openings, of the present application controls the primary direction of the light rays incident on the extraction features 84, in some applications it may also be desirable to further control the distribution of angles around the primary directions within the waveguide. Such control can generally be achieved via a number of optical surfaces, such as the primary optics or the lens of the LED element, the coupling surface of the waveguide, etc. Control of the angular distribution of light within the waveguide and a careful design of the extraction features together with the waveguide coupling surfaces and the primary component optics can further control the angular distribution of light.Provides control over the emitted brightness distribution, illumination distribution, optical efficiency, and directional characteristics of the luminaire. Even in cases where light within the waveguide is not well controlled, the extraction features with apertures can provide improved control over the distribution and efficiency of the extracted light. In both cases, highly controlled beams can either be extracted in a collimated manner or distributed in a wide pattern for various selectable illumination patterns, depending on the aperture.

[0055] Taken together, a number of factors can influence the illumination distribution emitted by the waveguide. The shape of the extraction feature, along with the spacing and pattern of the multiple extraction features, affects the extraction efficiency, the amount of light emitted from the first surface of the waveguide (the directivity characteristic), the brightness, and the illumination of the luminaire. For example, an asymmetrically shaped extraction feature can produce an asymmetric 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 corresponds to the distance(s) between the first surface of the waveguide and the base(s) of the extraction feature(s)—significantly affects the illumination distribution pattern. For example, the luminaire of Fig. 2. An asymmetrical distribution is produced when the spacing is approximately 125 pm, whereas the luminaire produces a more symmetrical distribution when the spacing is approximately 600 µm. In other embodiments, a change in the spacing can result in a "spot light," a "Lambertian," or a "wall wash" illumination distribution. Another consideration in the design of such extractors is the primary direction in which the light propagates through the waveguide. In an extreme comparison, a square waveguide illuminated from a single edge can produce an asymmetrical illumination pattern, whereas a circular waveguide illuminated around its circumference will produce a highly symmetrical illumination pattern.Various types of lamps and luminaires, including those requiring a dispersive or Lambertian lighting distribution (for example, typically ceiling lights for general lighting), collimating distributions (for example, downward-facing lights or spotlights), and specific lighting patterns (for example, street lighting, architectural lighting) can be realized using the optical waveguide and extraction features provided here.

[0056] Referring again to Fig. Figure 12 shows that the luminaire 50 comprises the waveguide 54, the extraction features 84, and the element 108, which are made of the same material, so that the refractive index is consistent. In this case, light is not refracted when it passes through the aperture 100. In contrast, the illustration Fig. 13 a plurality of extraction features 84 and an element 108 on a waveguide 54, wherein the material of the waveguide 54 differs from the material of the extraction features 84 and the element 108. In this case, light is refracted when it propagates from the waveguide 54 into the extraction features 84. In still other embodiments, a region 126 ( Fig. 13) Between extraction features 84, after attachment to the waveguide 54, partially or entirely comprise a material other than air. For example, the material may have a refractive index that differs significantly from that of the waveguide 54 and the element 108. Furthermore, the refractive index of the element 108 may differ from that of the waveguide 54 and / or the extraction features 84 in order to achieve refraction at such transitions (interfaces). In some embodiments, it may be desirable to use refraction to control the extraction and the resulting illumination distribution.

[0057] Other parameters, such as the shape, density, and material of the extraction features, can also be modified to produce different illumination patterns. Other methods for achieving directional light extraction, such as combinations of refractive index differences in the waveguide or in elements attached to the waveguide, and modifications to the shape of the waveguide itself, could also be used to alter the illumination pattern. Furthermore, a multi-layered protective material can optionally be applied to the first and second surfaces. This protective material can be removed layer by layer during use of the luminaire to quickly provide a clear (i.e., transparent) viewing / emission surface in dirty working environments.

[0058] The high degree of light directivity, made possible by the proper design of the orifice-equipped extraction features, opens up a wide range of potential lighting applications. For example, highly directional emission allows a viewer to look at a reflective surface through the waveguide without their view being significantly obstructed by the illumination or the light emitted by the luminaire. In particular, a viewer can look through the luminaire at an illuminated area, as in Fig.Figure 1 shows this. Additionally, the viewer can see the illumination provided by the luminaire without perceiving significant brightness, even while the second surface from which the light is emitted is visible. The luminaire can also provide high levels of illumination from a surface source (instead of a point source) while concealing the light source and / or reducing or eliminating direct glare from the source as well as reflected glare away from the surfaces.

[0059] The concept of concealed or hidden lighting with visible illumination, made possible by the light's directional characteristics, finds many applications in the field of architectural and display lighting. For example, in one embodiment, a housing for an artwork can comprise a glass or acrylic waveguide with a lens-shaped microfield film bonded to it, mounted within a frame, with the light sources for the waveguide located within the frame. The waveguide serves both as protection for the artwork and as a light source for illuminating it in a way that makes the light source imperceptible. Light extracted through the film towards the artwork provides uniform illumination without the use of external light sources, while still allowing a viewer to see through the glass or acrylic waveguide.Similarly, such approaches could be used in a variety of display cases, aquariums, etc.

[0060] In another embodiment, a luminaire providing concealed lighting can illuminate a room. The luminaire may comprise a waveguide made of a clear material, such as glass or acrylic, with extraction features, such as the lens-like microfield film bonded to it. An array of LED elements may be arranged on one or more edges of the waveguide. The waveguide may be approximately 1 / 8 inch thick and may be approximately 6 inches by 24 inches, approximately 2 feet by 2 feet, or approximately 2 feet by 4 feet, although other dimensions may be used as desired. The luminaire can be positioned to provide illumination for preferred surfaces in the room, such as a wall, floor, or ceiling, and arranged so that the illumination is directed away from people in the room.In one embodiment, a light fixture can be mounted on a ceiling, with the light-emitting surface of the waveguide directed toward the wall. The fixture can be positioned approximately twelve inches from the wall, so that the wall is illuminated. The reflection of the light from the wall illuminates a section or the entire room, creating the appearance that the surfaces are lit without any obvious or visible light source. In other embodiments, the light fixture can be designed to provide specially tailored and / or adjustable lighting patterns. Generally, such light sources would be "indirect" in the sense that a surface is illuminated while the light source is concealed from view. Exemplary applications would include a pendant light, a side light, a wall sconce, a ceiling light, a task light, a track light, floor lamps, etc.include.

[0061] The luminaire could be used in a variety of other applications. For example, a work light using this luminaire allows the viewer to align their line of sight with the light distribution produced by the luminaire. The work light illuminates a surface, while the viewer is able to look directly through the waveguide onto the illuminated surface, rather than around it. The viewer could see into features such as drilled holes or other deep openings. Such a luminaire contrasts with a conventional work light, which necessarily must be positioned outside the viewer's direct line of sight, meaning the work light would not fully illuminate the interior of the hole or other deep openings.Another example is eyeglasses or protective goggles that emit light away from the viewer while projecting light back into the viewer's eyes.

[0062] In yet another example, a light fixture could appear as a clear panel when viewed from practical positions within a room, while providing illumination towards a wall, ceiling, desk, work area, or other surface or object. To the average observer, the fixture would give the impression that the light is generated by no visible source, thus providing flexibility in architectural design, aesthetic improvement, and glare reduction.Additional applications include a face shield, a splash guard at a salad bar, a window that illuminates an exterior area without the need for an external lighting system and wiring, or a security window that appears as a light to the occupants of a room but allows observers outside to see inside. Furthermore, the light can be mounted on a ceiling panel or suspended from a ceiling using a pendant mounting device. Each embodiment can incorporate piezoelectric materials and suspended particle devices that either include adjustable extraction features and / or allow the extraction features to be adjustable. Such adjustability would enable variable brightness and / or a variable illumination pattern.

[0063] Any of the embodiments disclosed herein may include a power supply circuit with 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 No. 14 / 291,829, filed May 30, 2014, entitled "High Efficiency Driver Circuit with Fast Response" by Hu et al. (Cree File No. P2276US1, Attorney File No. 034643-000618) or U.S. Patent Application No. 14 / 292,001, filed May 30, 2014, entitled "SEPIC Driver circuit with Low Input Current Ripple" by Hu et al. (Cree file number P2271US1, attorney file number 034643-000616), which are incorporated herein by reference as part of the present application.The circuit can also be used with a light control circuit arrangement that controls a color temperature of any of the embodiments disclosed herein in accordance with the input of a viewer, as disclosed in US patent application number 14 / 292,286, filed on May 30, 2014, entitled “Lighting Fixture Providing Variable CCT” by Pope et al. (Cree file number P2301 US1), which is incorporated herein by reference.

[0064] Furthermore, any of the embodiments disclosed herein may include one or more communication components forming part of the lighting control circuit arrangement, such as an RF antenna that detects RF energy. The communication components may, for example, be incorporated to enable the luminaire to communicate with other luminaires and / or with an external wireless controller, as disclosed in U.S. patent application number 13 / 782,040, filed on May 1, 2013, entitled "Lighting Fixture for Distributed Control," or U.S. patent application number 61 / 932,058, filed on January 27, 2014, entitled "Enhanced Network Lighting," both filed on behalf of the applicant of the present application, the disclosures of which are incorporated herein by reference.In general, the control circuit arrangement comprises at least one network component, one RF component, one control component, and one sensor. The sensor, such as a button-shaped sensor, can provide an indication of the ambient light level and / or occupancy within the room or the illuminated area. Such a sensor can be integrated into the lighting control circuit arrangement. COMMERCIAL APPLICABILITY

[0065] The extraction features disclosed herein efficiently extract light from the waveguide. At least some of the luminaires disclosed herein are specifically designed for use in installations such as outdoor devices (for example, streetlights, hall lights, roof lights) and indoor devices (for example, downward-facing lights, ceiling lights, a fold-in or fold-out application, a surface-mounted application on a wall or ceiling, etc.), which preferably require a total luminaire output of at least approximately 100 lumens or greater, and in some embodiments a total luminaire output of at least approximately 3000 lumens, and in other embodiments a total lumen output of approximately 10,000 to approximately 20,000 lumens. For example, in some industrial and commercial lighting applications, such as warehouse lighting, a total lumen output of up to 10,000 lumens might be required.000 lumens are desired. Furthermore, the luminaires disclosed herein preferably have a color temperature between approximately 2500 Kelvin and approximately 6200 Kelvin, and in some embodiments between approximately 2500 Kelvin and approximately 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 approximately 80 lumens per watt, more preferably at least approximately 100, and most preferably 120 lumens per watt. Furthermore, in some embodiments, the waveguide or waveguides exhibit an optical efficiency of at least approximately 80%, preferably at least 90%, and more preferably at least approximately 95%. Furthermore, 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 approximately 80%, and further preferably at least approximately 90%. A color rendering index (CRI) of at least approximately 80 is preferably achieved by at least some of the luminaires disclosed herein, with a CRI of at least approximately 88 being more preferred and at least approximately 90 being most preferred. Some luminaires exhibit a CRI of at least approximately 90 while maintaining a relatively high efficiency. Any desired particular output light distribution, such as a butterfly light distribution, could be achieved, including upward and downward light distributions, or only upward or only downward distributions, etc.

[0066] When using a relatively small light source emitting in a wide (e.g., Lambertian) angular distribution (which is typically the case for LED-based light sources), conservation of étendue, as generally understood in the field, 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 optical system must therefore generally achieve high collimation ratios. To achieve a large emission area in a more compact design, the prior art relies on the use of Fresnel lenses, which utilize refracting optical surfaces to align and collect the light. However, Fresnel lenses are generally planar by nature and are therefore not well suited for redirecting wide-angle light emitted from the source, resulting in a loss of optical efficiency.In contrast, in the embodiments described here, light is coupled into the optics, primarily 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 high-efficiency waveguide in a compact form factor is described in US patent application number 13 / 839,949, filed on March 15, 2013, entitled "Optical Waveguide and Lamp Including Same" (Cree file number P1961US1).

[0067] 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 a single pass through the waveguide in order to minimize losses.

[0068] In some embodiments, the desire may be to control the light rays in such a way that at least some of them are collimated, but in the same or other embodiments, the desire may also be to control all or some of the light rays in order to increase their angular dispersion, so that the light is not collimated. In some embodiments, the desire might be to collimate on narrow areas, while in other cases, the desire might be to do exactly the opposite.

Claims

[1] Luminaire (50), comprising: a case (64); an LED element (86) that is arranged in the housing (64); a waveguide (54) with a light-emitting surface (56) arranged in the housing (64) adjacent to the LED element (86); and an extraction feature (84) arranged on the light emission surface (56) of the waveguide (54); wherein the extraction feature (84) has a curved shape extending between an opening (100) adjacent to the light emission surface (56) and a base (102) opposite the opening (100), wherein a gap (106) is arranged between the light emission surface (56) of the waveguide (54) and the base (102) of the extraction feature (84), characterized by, that the extraction feature (84) has a first section (112) adjacent to the opening (100) with a truncated, curved surface and an adjacent second section (114) with a cylindrical or conical shape adjacent to the base (102). [2] Luminaire (50) according to claim 1, wherein the cut-off, curved surface of the extraction feature (84) has a section height (H1) corresponding to the height of the gap (106). [3] Luminaire (50) according to claim 2, wherein the height (H1) of the cut curved surface is adjusted such that the extraction feature (84) has a nearly hemispherical first section (112) with a flat surface at the tip. [4] Luminaire (50) according to one of the preceding claims, wherein the extraction feature (84) has an asymmetrical shape. [5] Luminaire (50) according to claim 4, wherein the first section (112) of the extraction feature (84) is hemispherical and the base (102) of the second section (114) is elliptical. [6] Luminaire (50) according to one of claims 4 to 5, wherein the extraction feature (84) has an asymmetric cross-section along the height (H1). [7] Luminaire (50) according to one of the preceding claims, wherein the first section (112) and the adjacent second section (114) have such a circumference that the cross-section transverse to a central axis (118) of the extraction feature (84) is circular over the entire height (H1) of the extraction feature (84). [8] Luminaire (50) according to any one of claims 1 to 6, wherein the first section (112) and the adjacent second section (114) have an elliptical or faceted cross-section. [9] Luminaire (50) according to any one of claims 2 to 8, wherein the base diameter d bthe extraction feature (84) is twice the height (H1). [10] Luminaire (50) according to one of the preceding claims, wherein the light incident on the first part (112) of the extraction feature (84) is directed downwards by total internal reflection. [11] Luminaire (50) according to one of the preceding claims, comprising a plurality of extraction features (84), wherein the extraction features (84) all have substantially the same shape. [12] Luminaire (50) according to one of the preceding claims, wherein a plurality of extraction features (84) are arranged on an element (108). [13] Luminaire (50) according to claim 12, wherein the majority of extraction features (84) are formed in a hexagonal field pattern on the element (108). [14] Luminaire (50) according to claim 12, wherein the extraction features (84) are at least partially irregularly spaced. [15] Luminaire (50) according to one of claims 11 to 14, wherein a center-to-center distance (D1) between adjacent extraction features (84) is in the range of less than twice the feature radius up to 10 mm, preferably twice the feature radius up to 5 mm. [16] Luminaire (50) according to one of the preceding claims, wherein a plurality of elements (108) with differently shaped extraction features (84) are connected to the waveguide (54). [17] Luminaire (50) according to claim 16, wherein the opening diameters d a , the base diameters d b and the heights (H) of the extraction features (84) are all the same or vary over the surface (56) of the waveguide. [18] Luminaire (50) according to one of the preceding claims, wherein a second outer surface (122) of the second part (114) has a conical shape forming an angle (β) with the base (102). [19] Luminaire (50) according to one of the preceding claims, wherein a body (96) of the extraction features (84) may include a bond feature (124) formed on the opening (100). [20] Luminaire (50) according to claim 19, wherein the connecting element (124) is convex. [21] Luminaire (50) according to claim 1, wherein the LED element (86) is arranged in a first end of the housing (64), and wherein the waveguide (54) extends from a second end of the housing (64) opposite the first end. [22] Luminaire (50) according to claim 21, wherein the LED element (86) is arranged along a coupling surface of the waveguide (54).

Images