Patent Description:
The present application comprises a continuation-in-part of International Application No. <CIT>, entitled "Optical Waveguide Body" (Cree docket No. P2225WO), and further comprises a continuation-in-part of <CIT>, entitled "Luminaire Utilizing Waveguide" (Cree docket No. P2237US1), and further comprises a continuation-in-part of <CIT>, entitled "Luminaire Utilizing Waveguide" (Cree docket No. P2237US2), and further comprises a continuation-in-part of <CIT>, entitled "Roadway Luminaire" (Cree docket No. P2265US1), all owned by the assignee of the present application.

The present application also claims the benefit of <CIT>, entitled "Roadway Luminaire" (Cree docket No. P2265US2), and <CIT>, entitled "Luminaire Utilizing Optical Waveguide" (Cree docket No. P2611US1), and International Application No. <CIT>, entitled "Luminaire Utilizing Waveguide" (Cree docket No. P2237WO2), all owned by the assignee of the present application.

The present application comprises a continuation-in-part of <CIT>, entitled "Luminaire Utilizing Waveguide" (Cree docket No. P2237US1), which also claims the benefit of <CIT>, entitled "Luminaire Utilizing Waveguide" (Cree docket No. P2237US0), <CIT>, entitled "Luminaire Utilizing Waveguide" (Cree docket No. P2237US0-<NUM>), and <CIT>, entitled "Luminaire Utilizing Waveguide" (Cree docket No. P2237US0-<NUM>), all owned by the assignee of the present application.

The present subject matter relates to optical devices, and more particularly, to a luminaire utilizing an optical waveguide.

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 includes three main components: one or more coupling elements, one or more distribution elements, and one or more extraction elements. The coupling component(s) direct light into the distribution element(s), and condition the light to interact with the subsequent components. The one or more distribution elements control how light flows through the waveguide and is dependent on the waveguide geometry and 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 optic, the primary considerations are: 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 in the coupling optic. One way of controlling the spatial and angular spread of injected light is by fitting each source with a dedicated lens. These lenses can be disposed with an air gap between the lens and the coupling optic, or may be manufactured from the same piece of material that defines the waveguide's distribution element(s). Discrete coupling optics allow numerous advantages such as higher efficiency coupling, controlled overlap of light flux from the sources, and angular control of how the injected light interacts with the remaining elements of the waveguide. Discrete coupling optics use refraction, total internal reflection, and surface or volume scattering to control the distribution of light injected into the waveguide.

After light has been coupled into the waveguide, it must be guided and conditioned to the locations of extraction. The simplest example is a fiber-optic cable, which is designed to transport light from one end of the cable to another with minimal loss in between. To achieve this, fiber optic cables are only gradually curved and sharp bends in the waveguide are avoided. In accordance with well-known principles of total internal reflectance, light traveling through a waveguide is reflected back into the waveguide from an outer surface thereof, provided that the incident light does not exceed a particular angle with respect to the surface tangent or, equivalently fall below a certain angle with respect to a surface normal.

In order for an extraction element to remove light from the waveguide, the light must first contact the feature comprising the element. By appropriately shaping the waveguide surfaces, one can control the flow of light across the extraction feature(s). Specifically, selecting the spacing, shape, and other characteristic(s) of the extraction features affects the appearance of the waveguide, its resulting distribution, and efficiency.

<CIT> discloses a waveguide bend element configured to change a direction of travel of light from a first direction to a second direction. The waveguide bend element includes a collector element that collects light emitted from a light source and directs the light into an input face of the waveguide bend element. Light entering the bend element is reflected internally along an outer surface and exits the element at an output face. The outer surface comprises beveled angular surfaces or a curved surface oriented such that most of the light entering the bend element is internally reflected until the light reaches the output face.

<CIT> discloses a light emitting panel assembly that comprises a transparent light emitting panel having a light input surface, a light transition area, and one or more light sources. Light sources are preferably embedded or bonded in the light transition area to eliminate any air gaps, thus reducing light loss and maximizing the emitted light. The light transition area may include reflective and/or refractive surfaces around and behind each light source to reflect and/or refract and focus the light more efficiently through the light transition area into the light input surface of the light-emitting panel. A pattern of light extracting deformities, or any change in the shape or geometry of the panel surface, and/or coating that causes a portion of the light to be emitted, may be provided on one or both sides of the panel members. A variable pattern of deformities may break up the light rays such that the internal angle of reflection of a portion of the light rays will be great enough to cause the light rays either to be emitted out of the panel or reflected back through the panel and emitted out of the other side.

Shipman, <CIT> discloses a combination running light reflector having two light sources, each of which, when illuminated, develops light that is directed onto a polished surface of a projection. The light is reflected onto a cone-shaped reflector. The light is transversely reflected into a main body and impinges on prisms that direct the light out of the main body.

<CIT> discloses various embodiments of architectural lighting that is distributed from contained radially collimated light. A quasi-point source develops light that is collimated in a radially outward direction and exit means of distribution optics direct the collimated light out of the optics.

<CIT> discloses light fixtures that use a variety of light sources, such as an incandescent bulb, a fluorescent tube and multiple LEDs. A volumetric diffuser controls the spatial luminance uniformity and angular spread of light from the light fixture. The volumetric diffuser includes one or more regions of volumetric light scattering particles. The volumetric diffuser may be used in conjunction with a waveguide to extract light.

<CIT> discloses illumination devices having multiple light emitting elements, such as LEDs disposed 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, which extracts the light.

Lighting Components, Inc. of Niles, Illinois, manufactures a waveguide having a wedge shape with a thick end, a narrow end, and two main faces therebetween. Pyramid-shaped extraction features are formed on both main faces. The wedge waveguide is used as an exit sign such that the thick end of the sign is positioned adjacent a ceiling and the narrow end extends downwardly. Light enters the waveguide at the thick end and is directed down and away from the waveguide by the pyramid-shaped extraction features.

Low-profile LED-based luminaires have recently been developed (e.g., General Electric's ET series panel troffers) that utilize a string of LED components directed into the edge of a waveguiding element (an "edge-lit" approach). However, such luminaires typically suffer from low efficiency due to losses inherent in coupling light emitted from a predominantly Lambertian emitting source such as a LED component into the narrow edge of a waveguide plane.

Smith <CIT> and <CIT> discloses a light direction device for use with LEDs. In one embodiment, the light direction device includes a plurality of opposing collimators disposed about a plurality of LEDs on one side of the device. Each collimator collimates light developed by the LEDs and directs the collimated light through output surfaces of the collimators toward angled reflectors disposed on a second side opposite the first side of the device. The collimated light reflects off the reflectors out of from the one side perpendicular thereto. In another embodiment, the collimators are integral with a waveguide having reflective surfaces disposed on a second side of the waveguide, and the collimated light is directed toward the reflective surfaces. The light incident on the reflective surfaces is directed from the one side of the device, as in the one embodiment. Patent publication <CIT> discloses a lighting device with coupling cavities having corrugations. Patent publication <CIT> discloses a light leading member with coupling cavities.

In some applications such as roadway, street, or parking lot lighting, it may be desirable to illuminate certain regions surrounding a light fixture while maintaining relatively low illumination of neighboring regions thereof. For example, along a roadway, it may be preferred to direct light in a x-dimension parallel with the roadway while minimizing illumination in a y-dimension toward roadside houses.

In accordance with one aspect, there is an optical waveguide as described in claim <NUM>.

According to one example useful for understanding the invention, an optical waveguide comprises a plurality of coupling cavities for directing light into a waveguide body spaced from a particular point. Further, each of the coupling cavities comprises a dimension that varies with distance from the particular point.

According to another example useful for understanding the invention, an optical waveguide comprising orthogonal x- and y-dimensions comprises a waveguide body of the optical waveguide that couples with a plurality of LED elements along the x-dimension. Further at least one light extraction member extends in the x-dimension for extracting light out of the waveguide body, and at least one plurality of light extraction members extend in the y-dimension for extracting light out of the waveguide body. Further still, the at least one plurality of light extraction members extends the length of the waveguide body and bisects the at least one light extraction member extending in the x-dimension.

According to a further example useful for understanding the invention, an optical waveguide comprising orthogonal x- and y-dimensions comprises at least one first light extraction member extending in the x-dimension for extracting light out of a waveguide body, and at least one plurality of light extraction members extend in the y-dimension for extracting light out of the waveguide body. Further, the at least one plurality of light extraction members forms a portion of the at least one first light extraction member.

Other aspects and advantages of the present invention will become apparent upon consideration of the following detailed description and the attached drawings wherein like numerals designate like structures throughout the specification.

Referring to <FIG>, <FIG>, <FIG>, and <FIG> two embodiments of a luminaire <NUM>, 100a that utilize a waveguide are illustrated. <FIG> illustrate an embodiment of the luminaire <NUM> having a relatively large size, and <FIG> illustrate an alternative embodiment of the luminaire 100a having a relatively smaller size. The embodiments disclosed herein are particularly adapted for use in general lighting applications, for example, as an outdoor roadway (including a driveway) or parking lot luminaire, or as any other indoor or outdoor luminaire. The inner and outer components of the embodiments <NUM>, 100a are substantially identical, except as to the size and configuration of optic assemblies <NUM> and waveguide bodies <NUM> utilized therein. Accordingly, only the components of the embodiment <NUM> are described in detail herein, with the exception that the waveguide bodies <NUM> and the optic assemblies <NUM> are separately described.

Each of the luminaires <NUM>, 100a includes a housing <NUM> adapted to be mounted on a stanchion or pole <NUM>. With reference to <FIG>, the housing <NUM> includes a mounting portion <NUM> that is sized to accept an end of any of a number of conventional stanchions. Fasteners <NUM>, such as threaded bolts, extend through apertures in side portions of fastening brackets <NUM> (only one of which is visible in <FIG>) and are engaged by threaded nuts <NUM> disposed in blind bores in an upper portion of the housing <NUM>. The stanchion <NUM> may be captured between the fastening brackets <NUM> and a lower surface of the upper portion of the housing to secure the luminaire <NUM> in fixed position on the end of the stanchion <NUM>. The housing <NUM> may alternatively be secured to the stanchion <NUM> by any other suitable means.

Referring to <FIG> and <FIG>, electrical connections (i.e., line, ground, and neutral) are effectuated via a terminal block <NUM> disposed within the mounting portion <NUM>. Wires (not shown) connect the terminal block <NUM> to an LED driver circuit <NUM> in the housing <NUM> to provide power thereto as noted in greater detail hereinafter.

Referring still to <FIG> and <FIG>, the luminaire <NUM> or 100a includes a head portion <NUM> comprising an upper cover member <NUM>, a lower door <NUM> secured in any suitable fashion to the upper cover member <NUM>, respectively, and an optic assembly <NUM> retained in the upper cover member <NUM>. A sensor <NUM> may be disposed atop the mounting portion <NUM> for sensing ambient light conditions or other parameters and a signal representative thereof may be provided to the LED driver circuit <NUM> in the housing <NUM>.

Further details of the luminaires <NUM>, 100a are disclosed in co-pending application Serial No., entitled "Luminaire Utilizing Light Emitting Diodes" filed herewith (Attorney docket number C0421/P2599US1), and Provisional Patent Application Serial No. <CIT>, entitled "Luminaire Utilizing Light Emitting Diodes" (Cree docket No. P2599US0).

Referring next to <FIG>, <FIG>, <FIG>, and <FIG>, the optic assembly <NUM> comprises an optical waveguide body <NUM> made of the materials specified hereinbelow or any other suitable materials, a surround member <NUM>, and a reflective enclosure member <NUM>. A circuit housing or compartment <NUM> with a cover is disposed atop the reflective enclosure member <NUM>, and the driver circuit <NUM> is disposed in the circuit compartment <NUM>. LED elements <NUM> are disposed on one or more printed circuit boards (PCBs) 246a, 246b and extend into coupling cavities or features <NUM> (<FIG>, <FIG>, and <FIG> ) of the waveguide body <NUM>, as noted in greater detail hereinafter. A heat exchanger <NUM> is disposed behind the one or more PCBs 246a, 246b to dissipate heat through vents that extend through the luminaire <NUM> and terminate at upper and lower openings <NUM>, <NUM>. In addition, the terminal block <NUM> is mounted adjacent the heat exchanger <NUM> and permits electrical interconnection between the driver circuit <NUM> and electrical supply conductors (not shown).

The LED elements <NUM> receive suitable power from the driver circuit <NUM>, which may comprise a SEPIC-type power converter and/or other power conversion circuits mounted on a printed circuit board <NUM>. The printed circuit board <NUM> may be mounted by suitable fasteners and location pins within the compartment <NUM> above the reflective enclosure member <NUM>. The driver circuit <NUM> receives power over wires that extend from the terminal block <NUM>.

Referring next to <FIG>, <FIG>, and <FIG>, an embodiment of the optical waveguide body <NUM> includes a top surface <NUM>, a bottom surface <NUM> forming a part of a substrate <NUM>, and at least one, and, more preferably, a plurality of light coupling cavities or features <NUM> extending into the waveguide body <NUM> from a coupling end surface <NUM>. Surface elements comprising a number of light redirection elements and light extraction members (described below) are disposed atop the substrate <NUM> and thus define the top surface <NUM>. Further surface elements comprising an optional plurality of light extraction features <NUM> (<FIG>) may be disposed on the bottom surface <NUM>. Alternatively, the bottom surface <NUM> may be textured or smooth and/or polished, or some combination thereof. LED elements (see <FIG>, <FIG>, <FIG>, <FIG>) <NUM> comprising individual LED light sources are disposed in or adjacent each of the plurality of light coupling cavities <NUM> as described in greater detail below.

The substrate <NUM> may be integral with the surface elements disposed on either the top surface <NUM> or bottom surface <NUM>, or one or more of the surface elements may be separately formed and placed on or otherwise disposed and retained relative to the substrate <NUM>, as desired. The substrate <NUM> and some or all of the surface elements may be made of the same or different materials. Further, some or all portions of some or all of the embodiments of the waveguide body <NUM> is/are made of suitable optical materials, such as one or more of acrylic, air, polycarbonate, molded silicone, glass, cyclic olefin copolymers, and a liquid (including water and/or mineral oils), and/or combinations thereof, possibly in a layered arrangement, to achieve a desired effect and/or appearance.

The light developed by the LEDs <NUM> travels through the waveguide body <NUM> and is redirected downwardly, by extraction features disposed on the top surface <NUM> to be described in detail below, and is emitted out the bottom or emission surface <NUM> of the waveguide body <NUM>. The optional light extraction features <NUM> on the bottom surface <NUM>, which may comprise two sets of parallel features extending transverse to the width (x-dimension - as indicated in <FIG> and <FIG>) of the waveguide body <NUM>, further facilitate light extraction. It should be noted that there could be a different number (including zero) of bottom surface light extraction features <NUM>, as desired. In any event, the Lambertian or other distributions of light developed by the LED elements <NUM> are converted into a distribution resulting in an illumination pattern having an extent in the x-dimension and a reach in the y-dimension perpendicular to the x-dimension.

The waveguide body <NUM> directs light developed by the LED element(s) <NUM> toward a desired illumination target surface, such as a roadway. The illumination pattern is preferably, although not necessarily, offset in at least the y-dimension with respect to a center of the waveguide body <NUM>. The extent of the illumination pattern on the target surface in the x-dimension is preferably (although not necessarily) greater than the width of the waveguide body <NUM> and is also preferably (although not necessarily) greater than the extent of the illumination pattern on the target surface in the y-dimension.

The illumination pattern may be modified through appropriate modification of the light extraction features <NUM> on the bottom surface <NUM> and the light extraction members and light redirection elements on the top surface <NUM>. The waveguide bodies shown in the illustrated embodiments cause the illumination pattern to be narrower in the y-dimension than in the x-dimension, although this need not be the case. Thus, for example, the light distribution may be equal in the x- and y-dimensions or the light distribution may be greater in the y-dimension than the distribution in the x-dimension. The brightness can be increased or decreased by adding or omitting, respectively, LED elements <NUM> and/or varying the power developed by the driver circuit <NUM>.

As should be apparent from the foregoing, the reflective enclosure member <NUM> is disposed above the waveguide body <NUM> opposite the substrate <NUM>. The reflective enclosure member <NUM> includes a lower, interior surface that is coated or otherwise formed with a white or specular material. Further, one or more of the surfaces of the waveguide body <NUM> may be coated/covered with a white or specular material. Light that escapes (or which would otherwise escape) the upper surface <NUM> of the waveguide body <NUM> may be thus reflected back into the waveguide body <NUM> so that light is efficiently extracted out of the substrate <NUM>. The lower surface of the reflective enclosure <NUM> may have other than a planar shape, such as a curved surface. In all of the illustrated embodiments, the light emitted out of the waveguide body <NUM> is preferably mixed such that point sources of light in the LED elements <NUM> are not visible to a significant extent and the emitted light is controlled and collimated to a high degree.

As seen in <FIG>, <FIG>, <FIG>, and <FIG>, each of the plurality of light coupling cavities <NUM> has an indentation-type shape, although variations in shape may be used to better manage the convergence or divergence of light inside the waveguide, in to improve light extraction. Each light coupling cavity <NUM> is defined by a surface <NUM> that is substantially or generally parabolic or bell-curve shaped in cross section (as seen in a cross section taken transverse to the coupling end surface <NUM> and parallel to the bottom surface <NUM>), as shown in such FIGS. Each cavity <NUM> may alternatively have the general shape of a triangular prism or tapered triangular prism (see <FIG>).

Each surface <NUM> defining each light coupling cavity <NUM> may be smooth, textured, curved, or otherwise shaped to affect light mixing and/or redirection. In embodiments, each coupling surface <NUM> includes spaced bumps or other features that protrude at points along a top-to-bottom extent (i.e., along a z-dimension normal to an x-y plane) of each cavity <NUM> in such a way as to delineate discrete coupling cavities <NUM> each provided for and associated with an individual LED element <NUM> to promote coupling of light into the waveguide body <NUM> and light mixing, as seen in <FIG> and <FIG> to be described in detail below. Such an arrangement may take any of the forms disclosed in International Application No. <CIT>, entitled "Optical Waveguide Body".

As seen in <FIG>, LED elements <NUM> are disposed within or adjacent the coupling cavities <NUM> of the waveguide body <NUM>. Each LED element <NUM> is a single white or other color LED, or each comprises multiple LEDs, which may be either mounted separately or together on a single substrate or package to form a module including, for example, at least one phosphor-coated or phosphor-converted LED, such as a blue-shifted yellow (BSY) LED, either alone or in combination with at least one color LED, such as a green LED, a yellow LED, a red LED, etc. The LED elements <NUM> may further include phosphor-converted yellow, red, or green LEDs. One possible combination of LED elements <NUM> includes at least one blue-shifted-yellow/green LED with at least one blue-shifted-red LED, wherein the LED chip is blue or green and surrounded by phosphor. Any combination of phosphor-converted white LED elements <NUM>, and/or different color phosphor-converted LED elements <NUM>, and/or different color LED elements <NUM> may be used. Alternatively, all the LED elements <NUM> may be the same. The number and configuration of LEDs <NUM> may vary depending on the shape(s) of the coupling cavities <NUM>. Different color temperatures and appearances could be produced using particular LED combinations, as is known in the art. In one embodiment, each light source comprises any LED, for example, an MT-G LED incorporating TrueWhite® LED technology or as disclosed in <CIT>, (Cree Docket No. P1912US1-<NUM>), as developed and manufactured by Cree, Inc. , the assignee of the present application. In embodiments, each light source comprises any LED such as the LEDs disclosed in <CIT>, and/or <CIT>, (Cree Docket No. P2589US0). In another embodiment, a plurality of LEDs may include at least two LEDs having different spectral emission characteristics. If desirable, one or more side emitting LEDs disclosed in <CIT> may be utilized inside or at the edge of the waveguide body <NUM>. In any of the embodiments disclosed herein the LED elements <NUM> preferably have a Lambertian light distribution, although each may have a directional emission distribution (e.g., a side emitting distribution), as necessary or desirable. More generally, any Lambertian, symmetric, wide angle, preferential-sided, or asymmetric beam pattern LED(s) may be used as the light source(s).

The sizes and/or shapes of the coupling cavities <NUM> may differ or may all be the same. Each coupling cavity <NUM> extends into the waveguide body <NUM> from an end surface <NUM>. However, the end surface <NUM> defining an open end of each coupling cavity <NUM> may not be coincident between cavities 156a, 156b. Thus, in the embodiment illustrated in <FIG>, each of the coupling cavities 156a has a depth that extends farther into the waveguide body <NUM> than coupling cavities 156b. Additionally, each of the coupling cavities 156b has an opening at the end surface <NUM> that is disposed farther from a center of the waveguide body <NUM> than corresponding openings of coupling cavities 156a. The cavities 156a are therefore relatively larger than the cavities 156b.

In the illustrated embodiment relatively larger BSY LED elements 136a (<FIG>) are aligned with coupling cavities 156a, while relatively smaller red LED elements 136b are aligned with coupling cavities 156b. The arrangement of coupling cavity shapes promotes color mixing in the event that, as discussed above, different color LED elements <NUM> are used and/or promotes illuminance uniformity by the waveguide body <NUM> regardless of whether multi-color or monochromatic LEDs are used. In any of the embodiments disclosed herein, other light mixing features may be included in or on the waveguide body <NUM>. Thus, for example, one or more bodies of differing index or indices of refraction than remaining portions of the waveguide body <NUM> may extend into the waveguide body and/or be located fully within the waveguide body <NUM>.

Referring now to <FIG> and <FIG>, the LED elements <NUM> may be disposed in the depicted arrangement relative to one another and relative to the light coupling cavities <NUM>. The LED elements <NUM> may be mounted on separate support structures <NUM> or some or all of the LED elements <NUM> may be mounted on a single support structure. In the illustrated embodiment of <FIG>, first and second subsets 256a and 256b of the LED elements <NUM> are disposed on and carried by first and second metal coated printed circuit boards (PCBs) 246a and 246b, respectively. Each PCB 246a and 246b is held in place relative to an associated opening 258a and 258b (see <FIG> and <FIG>), respectively, of the reflective enclosure member <NUM> by a holder assembly 248a and 248b (see <FIG>), respectively. The holder assemblies 248a and 248b are preferably identical (although this need not be the case), and hence, only the holder assembly 248a will be described in detail. The holder assembly 248a comprises a main holding member <NUM> and a gasket <NUM>. Each PCB 246a, 246b and/or each holder assembly 248a, 248b may be held in place relative to the waveguide body <NUM> by screws, rivets, etc. inserted through the PCB 246a, 246b and/or holder assembly 248a, 248b and passing into threaded protrusions 204a-204d that extend out from the waveguide body <NUM>. Further, screws or fasteners compress the main holding member <NUM> against the reflective enclosure member <NUM> with the gasket <NUM> disposed therebetween and the respective PCB 246a aligned with the associated opening 258a. Thereby the LED elements <NUM> are held in place relative to the waveguide body <NUM> by both the compressive force of the holder assembly 248a and the screws, rivets, etc. inserted through the PCB 246a and passing into threaded protrusions 204a, 204b.

Referring again to <FIG>, <FIG>, <FIG>, and <FIG>, the waveguide body <NUM> is disposed and maintained within the reflective enclosure member <NUM> such that the coupling cavities <NUM> are disposed in a fixed relationship adjacent the openings in the reflective enclosure <NUM> and such that the LED elements <NUM> are aligned with the coupling cavities <NUM> of the waveguide body <NUM>. Each LED receives power from an LED driver circuit or power supply of suitable type, such as a SEPIC-type power converter and/or other power conversion circuits carried by a circuit board that may be mounted by fasteners and/or locating pins atop the reflective enclosure member <NUM>.

<FIG>, <FIG>, and <FIG> illustrate the optic assembly <NUM> in greater detail. A process for fabricating the assembly <NUM> includes the steps of molding the waveguide body <NUM>, placing the reflective enclosure member <NUM> onto the waveguide body <NUM>, and overmolding the surround member <NUM> onto the waveguide body <NUM> and/or the reflective enclosure member <NUM> to maintain the reflective enclosure member <NUM>, the waveguide body <NUM>, and the surround member <NUM> together in a unitary or integral fashion. The optic assembly <NUM> further includes an upper cover <NUM> having curved and/or tapered side surfaces to interfit with the housing <NUM>, as shown in <FIG> and <FIG>. In each luminaire <NUM>, the reflective enclosure member <NUM> has a size and shape (including tapered or curved side surfaces) to receive closely the respective waveguide body <NUM> in a nesting fashion. The unitary aspect of the optic assembly <NUM> and the gaskets <NUM> provide a seal around the waveguide body <NUM>.

Any of the waveguide bodies disclosed herein may be used in the embodiments of <FIG> and <FIG>, including the waveguide bodies of <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>. For example, embodiments of the luminaire <NUM> may incorporate waveguide bodies <NUM> of a particular embodiment to achieve appropriate illumination distributions for desired output light illumination levels. The waveguide bodies of <FIG>, <FIG>, and <FIG> may be fabricated by a molding process, such as multilayer molding, that utilizes a tooling recess common to production of all three waveguide bodies, and using a particular bottom insert in the tooling cavity unique to each of the three waveguide bodies. The insert allows for a central section of each waveguide body <NUM> to have different extraction members and/or redirection elements while a bottom surface <NUM> and an outboard portion <NUM> of an upper surface <NUM> are common to the waveguides <NUM>. A similar molding process may be utilized for the fabrication of the waveguide bodies shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> as the waveguides shown herein also have commonly shaped bottom surface <NUM> and outboard portion <NUM>.

The different central sections of the waveguides allow for the illumination distribution pattern produced by the waveguide bodies <NUM> to be varied. The varied illumination distribution patterns may be compliant with the American Institute of Architects lighting standards that are commonly known in the art. The boundaries of each illumination pattern on the illuminated surface is defined by the threshold of minimum acceptable lighting conditions, which depend on the roadway requirements, such as for a highway luminaire or parking lot luminaire. For example, an embodiment of the waveguide body <NUM> may provide an illumination pattern on a target surface having a relatively shallow reach, for example, about one to about two times the mounting height of the luminaire <NUM>, 100a in the y-dimension extending away from the luminaire and a relatively long range distribution, for example, about three to about seven times the mounting height of the luminaire <NUM>, 100a in the x-dimension extending at either side of the luminaire <NUM>, 100a transverse to the y-dimension (for a total distribution width in the x-dimension of fourteen times the mounting height). The spacing of the luminaires could therefore be about one to about two times the mounting height along the y-dimension and about three to about seven times the mounting height along the x-dimension.

Alternatively, one or more of the embodiments of the waveguide body <NUM> may provide an illumination pattern having a relatively shallow reach, for example, about one to about three times the mounting height of the luminaire <NUM> in the y-dimension and a relatively medium range distribution, for example, about two to about six times the mounting height of the luminaire <NUM> in the x-dimension, such that the spacing of adjacent luminaires may be about one to about three times the mounting height along the y-dimension and about two to about six times the mounting height along the x-dimension.

Further still, the waveguide bodies <NUM> may produce an illumination pattern having a relatively mid-range reach, for example, about two to about four times the mounting height of the luminaire <NUM> in the y-dimension while having a relatively medium range distribution, for example, about <NUM> times the mounting height of the luminaire <NUM> in the x-dimension, for a spacing of adjacent luminaires of about two to about four times the mounting height along the y-dimension and about one to about five times the mounting height along the x-dimension. The illumination patterns may be different from the descriptions above depending on the number, spacing, colors, and orientation of the LEDs relative to the respective waveguide.

In a further alternative, the luminaire <NUM> may have a maximum length ranging from about <NUM> to about <NUM>, most preferably from about <NUM> to about <NUM>, a maximum width ranging from about <NUM> to about <NUM>, most preferably from about <NUM> to about <NUM>, and a maximum height ranging from about <NUM> to about <NUM>, most preferably from about <NUM> to about <NUM>. Likewise, the waveguide bodies <NUM> depicted in <FIG>, <FIG>, <FIG> may be used in a luminaire <NUM> having a lumen output ranging from about <NUM>,<NUM> lumens to about <NUM>,<NUM> lumens and, most preferably, in luminaires having a lumen output between about <NUM>,<NUM> lumens and about <NUM>,<NUM> lumens.

The luminaire 100a may have a maximum length along the y-dimension (as indicated in <FIG> and <FIG>) ranging from about <NUM> to about <NUM>, most preferably from about <NUM> to about <NUM>, a maximum width along the x-dimension ranging from about <NUM> to about <NUM>, most preferably from about <NUM> to about <NUM>, and a maximum height ranging from about <NUM> to about <NUM>, most preferably from about <NUM> to about <NUM>. Further, the waveguide bodies <NUM> depicted in <FIG>, <FIG>, and <FIG> may be used in a luminaire 100a having a lumen output ranging from about <NUM>,<NUM> lumens to about <NUM>,<NUM> lumens, and, most preferably, in a luminaire 100a having a lumen output between about <NUM>,<NUM> lumens to about <NUM>,<NUM> lumens.

The waveguide bodies <NUM> of <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> include the bottom surface <NUM>, and the outboard portion <NUM> of the top surface <NUM> is common to all of such waveguide bodies <NUM>. The bottom surface <NUM> illustrated in <FIG> is tray-shaped, and includes planar side surfaces 178a-178d disposed about an inner planar surface <NUM>. An outer planar surface <NUM> extends outwardly from and transverse to the side surfaces 178a-178d. An inner recessed section <NUM> includes two ridge-shaped light extraction members <NUM> spaced apart from one another and extending parallel to side surfaces 178a, 178c. A rib <NUM> protrudes from the inner recessed section <NUM> preferably along a center line <NUM> and parallel to the side surfaces 178a, 178c, of the waveguide body <NUM>. The center line <NUM> along which the rib <NUM> extends may be offset from center and instead be a particular line dividing the waveguide body <NUM>. Further, the center line <NUM> discussed below in describing the orientation of various waveguide body <NUM> features may instead be a particular line dividing the waveguide body <NUM>, such line being substantially centered or offset by a selected amount.

Referring to <FIG> and <FIG>, the outboard portion <NUM> of the upper surface <NUM> includes first and second opposed side surfaces 190a, 190b along either side of the waveguide body <NUM>. First and second side walls 194a, 194b extend along a portion of the first and second side surfaces 190a, 190b, respectively. Each side wall 194a, 194b includes a planar surface 196a, 196b defined by the respective side surfaces 190a, 190b and the respective inner side surfaces 192a, 192b. The outboard portion <NUM> further includes an end portion <NUM> having a wedge-shaped light extraction member <NUM> and a transition area <NUM>. The end surface <NUM> includes a planar surface <NUM> extending between two subsets of coupling cavities or features 266a, 266b that receive the light developed by the LED elements <NUM>. Further, the planar surface <NUM> on the coupling end <NUM> is subdivided by a central indentation <NUM> aligned with the rib <NUM>. The coupling cavities <NUM> are disposed adjacent to respective side walls 194a, 194b such that light incident on the side walls 194a, 194b is totally internally reflected within the waveguide body <NUM>. During use, first and second groups of light rays from first and second subsets 256a, 256b of LED elements <NUM> are reflected off of respective side walls 194a, 194b back towards the center of the waveguide body <NUM>. These light rays may be extracted through the respective members <NUM> of the bottom surface <NUM> toward the center line <NUM> such that the first and second groups of light rays cross one another at or near the center line <NUM> and in proximity to the rib <NUM>. Use of total internal reflection along the sides of the waveguide bodies <NUM> allows for a reduction in the size of the waveguide body along the x-dimension (i.e., the width of the waveguide body <NUM>).

Additionally, the four protrusions 204a-204d that are contacted by the PCBs 246a, 246b extend outwardly from the coupling end surface <NUM> of the waveguide body <NUM>. The portions of the four protrusions 204a-204d that face toward the coupling cavities <NUM> may be faceted or filleted, or may be smooth and/or polished.

In any of the embodiments, any sharp corner may be rounded and have a radius of curvature of less than <NUM>. Further, the linear extent of at least one extraction feature <NUM> (<FIG>) or <NUM> may extend substantially the entire width (see <FIG>) or <NUM> length of the waveguide (see <FIG>).

A central section <NUM> is disposed between the side walls 194a, 194b and extends between a coupling end surface <NUM> and non-coupling end surface <NUM> of the outboard portion <NUM>. The central section <NUM> is preferably (although not necessarily) symmetric about the center line <NUM> and includes two side sections 208a, 208b that are preferably mirror images of one another, and hence, only the side section 208a will be described in detail. The side section 208a includes a first plurality of wedge-shaped light extraction members <NUM> (shown in <FIG> and <FIG> as four members 210a-<NUM>, 210a-<NUM>, 210a-<NUM>, and 210a-<NUM>) extending between the side wall 194a and a planar rectangular portion 212a. A transition area 202a extends between the inner side surface 192a and the planar rectangular portion 212a. The transition area 202a may comprise a sloped surface <NUM> that may be polished, and/or may include faceting or scalloping on all or a portion of the sloped surface <NUM>, as seen in <FIG> in connection with another embodiment. As shown in <FIG>, <FIG>, <FIG>, each of the plurality of wedge-shaped light extraction members <NUM> includes sloping light extraction surfaces 210a-<NUM>, 210a-<NUM>, 210a-<NUM>, and 210a-<NUM>, respectively, similar or identical to the sloped surface <NUM> of the transition area 202a, that together direct light downwardly and out of the waveguide body <NUM>. <FIG> is a cross sectional view of the waveguide body <NUM> taken at plane <NUM> as indicated in <FIG>.

Referring again to <FIG>, <FIG>, and <FIG>, inner end surfaces 210a-<NUM>, 210a-<NUM>, 210a-<NUM><NUM>, 210a-<NUM> of the plurality of wedge-shaped light extraction members <NUM> and inner side surface 202a-<NUM> are spaced apart from a facing side wall 212a-<NUM> of the planar portion 212a to define a gap <NUM> therebetween. In the illustrated embodiment, the gap <NUM> is tapered such that the end of the gap <NUM> nearest the coupling end surface <NUM> is narrower than the end of the gap nearest the transition area <NUM>. A plurality of light redirection cavities <NUM> extend into the planar portion 212a. In the illustrated embodiment, there are nine cavities 168a-<NUM> through 168a-<NUM>. The cavities 168a-<NUM> through 168a-<NUM> are substantially or fully triangular in cross-sectional shape (as seen on <FIG>) whereas the cavities 168a-<NUM> through 168a-<NUM> are trapezoidal (again, as seen in <FIG>). Each cavity <NUM> has a base surface nearest the planar surface <NUM> (e.g., the base surfaces 168a-3a and 168a-8a) that are disposed at one or more angles relative to the planar surface <NUM>. The angle(s) may be equal or unequal and may range between about <NUM> degrees and about <NUM> degrees, preferably between about <NUM> degrees and about <NUM> degrees, and most preferably between about <NUM> degrees and about <NUM> degrees. Remaining side surfaces defining each cavity <NUM> form a prismatic shape with the base surface associated therewith. The cavities <NUM> redirect light traveling through the waveguide body <NUM> laterally within the waveguide body <NUM> toward the central section <NUM>. In other embodiments, the width, length, and curvature and/or other shape(s) of the light redirection cavities may vary. Further, the planar portion 212a may terminate at a linear surface <NUM> defining a truncated upper corner near the extraction member 210a-<NUM>. The surface is disposed at an angle relative to the planar surface <NUM> that is similar or identical to the angle specified above of one of the base surfaces of the cavities <NUM>. Light travelling through the waveguide is redirected at the linear surface <NUM> in a manner similar to the redirection effected by the cavities <NUM>.

A plurality of wedge-shaped light extraction members 218a-<NUM>, 218a-<NUM>, and a sloped transition area 201a are disposed between the planar portion 212a and the center line <NUM>, and extend between the coupling end surface <NUM> and the transition area <NUM> of the end portion <NUM>. <FIG> shows an example cross-sectional geometry of the extraction members <NUM> and the bottom surface extraction features <NUM> as indicated in <FIG>. The transition area 201a and the extraction features <NUM> direct light redirected by the cavities <NUM> out of the bottom surface <NUM> of the waveguide body <NUM>. Light is also directed outwardly through the surface <NUM> by the transition feature <NUM> and the wedge-shaped extraction member <NUM>. In this embodiment, the transition feature <NUM> comprises a curved shape, such as a "J" shape, as it meets the wedge-shaped extraction member <NUM>. The geometry of the extraction members <NUM> and extraction features <NUM> may be altered to manipulate the illumination pattern produced by the waveguide body <NUM>. Additionally, the extraction members <NUM> may have the same or similar shapes as the other light extraction features <NUM>, <NUM>, but may differ in size.

Referring now to <FIG>, the portion of the waveguide body <NUM> as indicated in <FIG> is shown. This portion of the waveguide body <NUM> includes the waveguide section 208a. In an embodiment, the section 208a may comprise the entirety of the waveguide body <NUM>. Alternatively, further section(s) that are substantially identical to and/or different than section 208a or sections having modified extraction members or redirection cavities as described hereinbelow may be arranged side-by-side for utilization and may together comprise the waveguide body <NUM>. In another embodiment, the sections similar or identical to the section 208a may be arranged in a configuration other than side-by-side, such as a square or rectangular configuration with coupling cavity subsets <NUM> arranged along more than one side surface. In other embodiments, sections may be identical, similar and/or different from other sections.

Referring still to <FIG>, the section 208a comprises different portions that are optically coupled to the LEDs, and depending on the embodiment, the light from the LEDs that is coupled to a portion can be directed (to be redirected again or extracted by another portion), redirected and extracted or extracted by that portion. Each section 208a has multiple portions with different features. Eventually the light is extracted to produce an overall or cumulative desired illumination pattern. In this example, the portion of the waveguide body section 208a comprises the coupling cavity subset <NUM> on the coupling cavity end surface <NUM>. Light from the LED subset 256a (as seen in <FIG>) is directed into the waveguide body <NUM>. The light is thereafter extracted from the waveguide body <NUM> by at least one of the extraction members <NUM>, <NUM> in a first direction or along a first dimension (such as the y-dimension). Alternatively, light from the LED subset 256a is redirected by redirection cavities <NUM> toward light extraction members <NUM>, <NUM>. Light from the LED subset 256a may also be redirected back towards the extraction features <NUM>, <NUM>, <NUM> by the side wall 194a or the side wall 212a-<NUM>. At least one light extraction feature, such as the light extraction feature 218a, directs light in a second direction or along a second dimension different than the first direction or first dimension (such as along the x-dimension). The configuration of the light extraction members <NUM>, <NUM>, <NUM> and the light redirection cavities <NUM> acts to direct substantially all of the light out of the bottom surface <NUM> of the waveguide section 208a. In alternative embodiments, additional subsets of LEDs <NUM> can be coupled into additional portions of the section 208a to be redirected and extracted, redirected (to be extracted in a different portion of the waveguide body <NUM> or directly extracted to produce a composite or cumulative desired illumination pattern. Note, subsets of LEDs <NUM> can be coupled to multiple portions of each section 208a or even across sections depending on the embodiment. In an example embodiment, the optical waveguide comprises the plurality of coupling cavities <NUM> for coupling light into the waveguide body <NUM> from the plurality of LEDs <NUM>. The optical waveguide further comprises a first light extraction feature (such as any of the light extraction members <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> described herein) extracting light directly out of the waveguide body <NUM> in a first direction. Further in this embodiment, the optical waveguide my comprise a light redirection feature (such as redirection cavities <NUM> described herein) for directing light within the waveguide body <NUM>, and a second light extraction feature (again, such as any of the light extraction members <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> described herein) for extracting redirected light out of the waveguide body <NUM> in a second direction different than the first direction.

The bottom surface <NUM> of the waveguide body <NUM> of <FIG> is substantially identical to the bottom surface <NUM> shown in <FIG>. Referring now to <FIG>, the central section <NUM> of the waveguide body <NUM> is similar to the central section of the waveguide body of <FIG> except for the following differences. As with the previous embodiments, the central section <NUM> of the waveguide body <NUM> of <FIG> includes two side sections 208a, 208b that are preferably mirror images of one another. The planar surfaces 212a, 212b and central indentation <NUM> shown in the central section of <FIG> are similar to those in <FIG>. Each side section 208a, 208b includes first and second pluralities of wedge-shaped light extraction members <NUM>-<NUM>, <NUM> that are disposed transverse to one another. However, a planar surface <NUM>-196a shown in <FIG> is relatively smaller than the planar surface 196a of <FIG>. In this embodiment, inner side surface <NUM>-192a is spaced apart from a facing wall <NUM>-202a-<NUM> to define a gap <NUM> therebetween.

The side section 208a of this embodiment includes the first plurality of wedge-shaped light extraction members <NUM>-<NUM> (shown in <FIG> as two members <NUM>-210a-<NUM> and <NUM>-210a-<NUM>) extending between the side wall 194a and the planar rectangular portion 212a. A transition area <NUM>-202a extends between the inner side surface 192a and the planar rectangular portion 212a. The transition area <NUM>-202a may comprise a sloped surface <NUM>-<NUM>. As shown in <FIG>, each of the plurality of wedge-shaped light extraction members <NUM>-<NUM> includes sloping light extraction surfaces <NUM>-210a-<NUM> and <NUM>-210a-<NUM>, respectively, similar or identical to a sloped surface <NUM>-<NUM> of the transition area <NUM>-202a, that together direct light downwardly and out of the waveguide body <NUM>. The plurality of wedge-shaped light extraction members <NUM>-<NUM> and the transition area <NUM>-202a have more gradual sloped surfaces <NUM>-210a-<NUM>, <NUM>-210a-<NUM>, <NUM>-<NUM> as compared to the plurality of wedge-shaped light extraction members <NUM> in the embodiment of <FIG>. In <FIG>, as in <FIG>, the extraction members <NUM> and transition area 201a extend between the planar surface <NUM> and the transition area <NUM> of the end portion <NUM>.

Referring again to <FIG>, inner end surfaces <NUM><NUM>-210a-<NUM>, <NUM><NUM>-210a-<NUM> of the plurality of wedge-shaped light extraction members <NUM>-<NUM> and inner side surface <NUM>-202a-<NUM> are spaced apart from a facing side wall 212a-<NUM> of the planar portion 212a to define a gap <NUM>-<NUM> therebetween. In this embodiment, the gap <NUM>-<NUM> is truncated by a protrusion <NUM> from the side wall 212a-<NUM> such that nearest the coupling end surface <NUM> the gap ends approximately half way along the inner side surface <NUM>-202a-<NUM>. The gap <NUM>-<NUM> is not tapered in the embodiment pictured in <FIG>.

A plurality of light redirection cavities <NUM>-<NUM> extend into the planar portion 212a. In the illustrated embodiment, there are eight cavities <NUM>-168a-<NUM> through <NUM>-168a-<NUM>. In this embodiment, all of the cavities <NUM>-168a-<NUM> through <NUM>-168a-<NUM> are substantially or fully trapezoidal in cross-sectional shape. Each cavity <NUM>-168a-<NUM> through <NUM>-168a-<NUM> has a base surface nearest the planar surface <NUM> that may be disposed at one or more angles relative to the planar surface <NUM> similar to the cavities 168a-<NUM> through 168a-<NUM> of <FIG>. Likewise, each cavity <NUM>-168a-<NUM> through <NUM>-168a-<NUM> comprises a prismatic shape similar to the cavities 168a-<NUM> through 168a-<NUM> of <FIG>.

A plurality of wedge-shaped light extraction members 218a-<NUM>, 218a-<NUM>, and a sloped transition area 201a are disposed between the planar portion 212a and the center line <NUM>, and extend between the coupling end surface <NUM> and the transition area <NUM> of the end portion <NUM>. The transition area 201a and the extraction features <NUM> direct light redirected by the cavities <NUM> out of the bottom surface <NUM> of the waveguide body <NUM>. Light is also directed outwardly through the surface <NUM> by the transition feature <NUM> and the wedge-shaped extraction member <NUM>. As in the previous embodiment, the transition feature <NUM> may comprise a curved shape, such as a "J" shape, as it meets the wedge-shaped extraction member <NUM>. <FIG> shows an example cross-sectional geometry of the extraction members <NUM> and the bottom surface extraction features <NUM> as indicated in <FIG>. As previously discussed, the geometry of the extraction members <NUM> and extraction features <NUM> may be altered to manipulate the illumination pattern produced by the waveguide body <NUM>.

The bottom surface <NUM> of the waveguide body <NUM> of <FIG> is substantially identical to the bottom surface <NUM> shown in <FIG> and <FIG>. Referring now to <FIG>, the central section <NUM> of the waveguide body <NUM> is similar to the central section of the waveguide body of <FIG> except for the following differences. As with the previous embodiments, the central section <NUM> of the waveguide body <NUM> of <FIG> includes two side sections 208a, 208b that are preferably mirror images of one another. Planar surface <NUM>-196a in <FIG> is relatively smaller than the planar surface 196a of <FIG>. Planar surfaces 212a, 212b from <FIG> are omitted in <FIG>, but the central indentation <NUM> on the planar surface <NUM> remains. Each side section 208a, 208b includes a first plurality of light extraction members <NUM>-<NUM> disposed transverse to the plurality of light extraction members <NUM>.

The side section 208a of this embodiment includes the first plurality of wedge-shaped light extraction members <NUM>-<NUM> (shown in <FIG> as two members <NUM>-210a-<NUM> and <NUM>-210a-<NUM>) extending between the side wall 194a and transition area <NUM>-201a. A transition area <NUM>-202a extends between the inner side surface 192a and the transition area <NUM>-201a. The transition area <NUM>-202a may comprise a sloped surface <NUM>-<NUM>. As shown in <FIG>, each of the plurality of wedge-shaped light extraction members <NUM>-<NUM> includes sloping light extraction surfaces <NUM>-210a-<NUM> and <NUM>-210a-<NUM>, respectively, similar or identical to a sloped surface <NUM>-<NUM> of the transition area <NUM>-202a, that together direct light downwardly and out of the waveguide body <NUM>. The plurality of wedge-shaped light extraction members <NUM>-<NUM> and the transition area <NUM>-202a have more steeply sloped surfaces <NUM>-210a-<NUM>, <NUM>-210a-<NUM>, <NUM>-<NUM> as compared to the plurality of light extraction members <NUM> in the embodiment of <FIG>. In <FIG>, as in <FIG> and <FIG>, the extraction members <NUM> and transition area <NUM>-201a extend between the planar surface <NUM> and the transition area <NUM> of the end portion <NUM>.

In this embodiment, a single light redirection cavity <NUM>-<NUM> extends into the transition areas <NUM>-201a and <NUM>-202a. In the illustrated embodiment, there is one cavity <NUM>-168a, <NUM>-168b on each side section 208a, 208b. Further in this embodiment, the cavity <NUM>-168a is substantially or fully trapezoidal in cross-sectional shape. The cavity <NUM>-168a has a base surface nearest the planar surface <NUM> that is disposed at an angle relative to the planar surface <NUM> similar to the cavities 168a-<NUM> through 168a-<NUM> of <FIG>. Likewise, the cavity <NUM>-168a comprises a prismatic shape similar to the cavities 168a-<NUM> through 168a-<NUM> of <FIG>. <FIG> shows an example cross-sectional geometry of the extraction members <NUM> and the bottom surface extraction features <NUM> as indicated in <FIG>. Just as in previous embodiments, the geometry of the extraction members <NUM> and extraction features <NUM> may be altered to manipulate the illumination pattern.

Referring now to <FIG> and <FIG>, the transition surface <NUM>-<NUM> is smooth on a portion nearest the transition area <NUM>-201a and scalloped or faceted on a portion nearest the inner side surface 192a. The relative proportions of scalloped-to-smooth surfaces on the transition surface <NUM>-<NUM> may be altered, but the embodiment depicted in <FIG> shows relatively more smooth surface than scalloped surface.

Referring still to <FIG>, the coupling cavities <NUM> of the side section 208a of the waveguide body <NUM> are shown in detail. As discussed above with reference to <FIG>, the sizes and/or shapes of the coupling cavities <NUM> may differ or may all be the same. Thus, in the embodiment illustrated in <FIG>, each of the coupling cavities 156a has a depth that extends farther into the waveguide body <NUM> than nearby coupling cavities 156b. However, the depth each coupling cavity <NUM> extends into the waveguide body <NUM> is deepest near the first and second protrusions 204a, 204b. The depth each coupling cavity <NUM> extends into the waveguide body <NUM> is shallowest near a center line <NUM> of the coupling cavity subset 266a on the side section 208a. As with center line <NUM>, the center line <NUM> of each side section 208a, 208b may be substantially centered or may instead be a particular line offset to either side by a selected amount, such particular line dividing each section 208a, 208b of the waveguide body.

Each light coupling cavity <NUM> is defined by a surface <NUM> that is substantially or generally parabolic or bell-curve shaped in cross section (as seen in a cross section taken transverse to the coupling end surface <NUM> and parallel to the bottom surface <NUM>), as discussed above. In addition, the coupling cavity surface <NUM> increases in width and decreases in depth the nearer each coupling cavity <NUM> is to the center line <NUM>. Thus, the focal point of each parabolic coupling cavity surface <NUM> is disposed nearer the coupling end surface <NUM> the nearer the particular coupling cavity <NUM> is to the center line <NUM> of side 208a. The focal length of each parabolic coupling cavity <NUM> may become longer or shorter according to the above described relation to the center line <NUM>. Alternatively, according to the invention, the focal length changes with dependence on the center line <NUM>. Other patterns may also determine the relative change in focal length of each parabolic coupling cavity <NUM>. The change in shape may be the same or different for the BSY coupling cavities 156a and the red coupling cavities 156b.

<FIG> depict the medium sized luminaire 100a as discussed above. The waveguide bodies shown in and described with respect to <FIG> and <FIG> may be suitable for use with the medium sized luminaire 100a. Referring now to <FIG>, the top surface <NUM> of the waveguide body <NUM> is shown. The central section <NUM> of the waveguide body <NUM> is similar to the central section of the waveguide body of <FIG> except for the following differences. As with the previous embodiments, the central section <NUM> of the waveguide body <NUM> of <FIG> includes two side sections 208a, 208b that are preferably mirror images of one another.

The planar surfaces 212a, 212b shown in the central section of <FIG> are larger relative to the first plurality of wedge-shaped light extraction members <NUM>-<NUM>. Also, the central indentation <NUM> previously shown in the central section <NUM> of <FIG>, is omitted. Each side section 208a, 208b includes first and second pluralities of wedge-shaped light extraction members <NUM>-<NUM>, <NUM> that are disposed transverse to one another. However, planar surface 196a shown in <FIG> is omitted in the embodiment of <FIG>. In this embodiment, side surface <NUM>-190a forms side surfaces of light extraction members <NUM>-<NUM> and transition area <NUM>-202a.

The wedge-shaped light extraction members of the first plurality <NUM>-<NUM> (shown in <FIG> as three members <NUM>-210a-<NUM>, <NUM>-210a-<NUM>, and <NUM>-210a-<NUM>) and the transition area <NUM>-202a extend between the side surface <NUM>-190a and the planar rectangular portion 212a. The transition area <NUM>-202a extends between the side surface <NUM>-190a and the planar rectangular portion 212a. The transition area <NUM>-202a may comprise a sloped surface <NUM>-<NUM>. As shown in <FIG>, each of the plurality of wedge-shaped light extraction members <NUM>-<NUM> includes sloping light extraction surfaces <NUM>-210a-<NUM>, <NUM>-210a-<NUM>, and <NUM>-210a-<NUM>, respectively, similar or identical to the sloped surface <NUM>-<NUM> of the transition area <NUM>-202a, that together direct light downwardly and out of the waveguide body <NUM>.

The plurality of wedge-shaped light extraction members <NUM>-<NUM> and the transition area <NUM>-202a have sloped surfaces <NUM>-210a-<NUM>, <NUM>-210a-<NUM>, <NUM>-210a-<NUM>, <NUM>-<NUM> that vary in steepness of slope. Sloped surfaces <NUM>-210a-<NUM> and <NUM>-<NUM> have the most gradual slope (and perhaps identical slope), while sloped surface <NUM>-210a-<NUM> is more steeply sloped, and sloped surface <NUM>-210a-<NUM> is the most steeply sloped surface of the embodiment of <FIG>. The transition surface <NUM>-<NUM> of <FIG> is smooth.

A plurality of light redirection cavities <NUM>-<NUM> extend into the planar portion 212a. In the embodiment of <FIG>, there are eight cavities <NUM>-168a-<NUM> through <NUM>-168a-<NUM>. In this embodiment, all of the cavities <NUM>-168a-<NUM> through <NUM>-168a-<NUM> are substantially or fully trapezoidal in cross-sectional shape. The cavities <NUM>-168a-<NUM> through <NUM>-168a-<NUM> each have base surfaces nearest the planar surface <NUM> that are disposed at one or more angles relative to the planar surface <NUM> similar to the cavities 168a-<NUM> through 168a-<NUM> of <FIG>. Likewise, each cavity <NUM>-168a-<NUM> through <NUM>-168a-<NUM> comprises a prismatic shape similar to the cavities 168a-<NUM> through 168a-<NUM> of <FIG>. The light redirection cavities <NUM>-<NUM> are arranged partially spanning the planar surface 212a and the transition area <NUM>-201a. Redirection cavity <NUM>-168a-<NUM> partially spans the planar surface 212a, the transition area <NUM>-201a and the transition area <NUM>-<NUM>.

A plurality of wedge-shaped light extraction members 260a-<NUM>, 260a-<NUM>, and a sloped transition area <NUM>-201a are disposed between the planar portion 212a and the center line <NUM>, and extend between the coupling end surface <NUM> and the non-coupling end surface <NUM>. The transition area <NUM>-201a and the extraction features <NUM> direct light redirected by the cavities <NUM> out of the bottom surface <NUM> of the waveguide body <NUM>. Light is also directed outwardly through the surface <NUM> by the transition feature <NUM>-205a and a wedge-shaped extraction member <NUM>. The geometry of the extraction members <NUM> and extraction features <NUM> may be altered to manipulate the illumination pattern produced by the waveguide body <NUM>. Additionally, the extraction members <NUM> may have the same or similar shapes as the other light extraction features <NUM>, <NUM>-<NUM>, but may differ in size.

<FIG> shows an example cross-sectional geometry of the extraction members <NUM> and the bottom surface extraction features <NUM> as indicated in <FIG>. As previously discussed, the geometry of the extraction members <NUM> and extraction features <NUM> may be altered to manipulate the illumination pattern produced by the waveguide body <NUM>. In the embodiment of <FIG>, the wedge-shaped extraction features <NUM>, <NUM>-<NUM>, and <NUM> and the light redirection cavities <NUM>-<NUM> are arranged to develop an illumination pattern for relatively wider street coverage when the optical assembly <NUM> is used in a streetlight application.

A transition area <NUM>-205a is arranged between the wedge-shape light extraction member <NUM> of the non-coupling end portion <NUM> and both the wedge-shaped light extraction member <NUM>-210a-<NUM> and planar portion 212a. The transition area <NUM>-205a does not extend the full width of the outboard portion <NUM> on the non-coupling end portion <NUM>. In this embodiment, the wedge-shaped light extraction members <NUM> run the full length of the outboard portion <NUM> from the coupling end surface <NUM> to the non-coupling end surface <NUM>. End portions of the wedge-shaped light extraction members <NUM> form a part of the wedge-shaped light extraction member <NUM> on the non-coupling end portion <NUM>.

Referring now to <FIG>, the bottom surface <NUM> is substantially identical to the bottom surface <NUM> shown in <FIG>. As discussed with respect to previous embodiments, the outer planar surface <NUM> extends outwardly from and transverse to the side surfaces 178a-178d. Outer planar surface <NUM> may be formed from transparent or other material capable of internal reflection. Light may escape into the outer planar surface <NUM> from the waveguide body <NUM>. It further may be desirable for all light to be extracted from the luminaire 100a, and thus, outer planar surface <NUM> (shaded in the embodiment depicted in <FIG>) may be textured on the emission surface such that any light internally reflected within the outer planar surface <NUM> is extracted in the same general direction as light extracted from the inner recessed section <NUM> of the waveguide body <NUM>.

Referring now to <FIG>, the coupling cavities <NUM> are shown in greater detail. High angle heavily textured light shield portions <NUM> of coupling cavity surfaces <NUM> of the red coupling cavities 156b are shaded in <FIG>. These diffusing portions <NUM> are arranged between each respective red LED element 136b and the body of the waveguide <NUM>. The shield portions <NUM> prevent red strips. To further enhance color mixing, light mixing bumps <NUM> are disposed on the coupling cavity surfaces <NUM>. <FIG> shows light rays entering the waveguide body <NUM> from BSY and red LED elements 136a, 136b. The dispersion of the light rays once coupled into the waveguide body illustrates the diffusion and color mixing effects of the shield portions <NUM> and light mixing bumps <NUM>. Other portions of the coupling cavity surfaces <NUM> may be textured instead, or in addition to, the light shield portions <NUM> to manipulate the diffusion and color mixing properties of the coupling cavities <NUM>. <FIG> further show an embodiment with asymmetric coupling cavity surface geometry for increasing controlled light coupled into the waveguide body <NUM>. In this embodiment, the light shield portion <NUM> extends further from the waveguide body <NUM> than facing portion <NUM>. The coupling cavity geometry may be symmetric or asymmetric for both the BSY and red LED elements 136a, 136b. The symmetry or asymmetry of the coupling cavities <NUM> may repeat or be random. Further depicted in <FIG>, surfaces <NUM> and <NUM> are also asymmetric such that surface <NUM> of BSY coupling cavity 156a is relatively longer or larger as compared with facing surface <NUM> of the same cavity.

Referring now to <FIG>, the top surface <NUM> of the waveguide body <NUM> is shown. The central section <NUM> of the waveguide body <NUM> is similar to the central section of the waveguide body of <FIG> except for the following differences. As with the previous embodiments, the central section <NUM> of the waveguide body <NUM> of <FIG> includes two side sections 208a, 208b that are preferably mirror images of one another.

Each side section 208a, 208b includes first and second pluralities of wedge-shaped light extraction members <NUM>-<NUM>, <NUM> that are disposed transverse to one another. The planar surfaces 212a, 212b shown in the central section of <FIG> are larger relative to the first plurality of wedge-shaped light extraction members <NUM>-<NUM>. However, planar surface 196a shown in <FIG> is omitted in the embodiment of <FIG>, as is indentation <NUM>. In this embodiment, side surface <NUM>-190a forms side surfaces of light extraction members <NUM>-<NUM> and transition area <NUM>-202a.

The wedge-shaped light extraction members of the first plurality <NUM>-<NUM> (shown in <FIG> as three members <NUM>-210a-<NUM>, <NUM>-210a-<NUM>, and <NUM>-210a-<NUM>) and the transition area <NUM>-202a extend between the side surface <NUM>-190a and the planar rectangular portion 212a. The transition area <NUM>-202a may comprise a sloped surface <NUM>-<NUM>. As shown in <FIG>, each of the plurality of wedge-shaped light extraction members <NUM>-<NUM> includes sloping light extraction surfaces <NUM>-210a-<NUM>, <NUM>-210a-<NUM>, and <NUM>-210a-<NUM>, respectively, similar or identical to the sloped surface <NUM>-<NUM> of the transition area <NUM>-202a, that together direct light downwardly and out of the waveguide body <NUM>.

The sloped surfaces <NUM>-210a-<NUM>, <NUM>-210a-<NUM>, <NUM>-210a-<NUM>, <NUM>-<NUM> vary in degree of slope in this embodiment. Sloped surfaces <NUM>-210a-<NUM>, <NUM>-210a-<NUM>, and <NUM>-<NUM> have moderate slope, while sloped surface <NUM>-210a-<NUM> is relatively more gradually sloped. The transition surface <NUM>-<NUM> of <FIG> is smooth.

A plurality of light redirection cavities <NUM>-<NUM> extend into the planar portion 212a. In the embodiment of <FIG>, there are eight cavities <NUM>-168a-<NUM> through <NUM>-168a-<NUM>. In this embodiment, all of the cavities <NUM>-168a-<NUM> through <NUM>-168a-<NUM> are substantially or fully trapezoidal in cross-sectional shape. The cavities <NUM>-168a-<NUM> through <NUM>-168a-<NUM> each have base surfaces nearest the planar surface <NUM> that are disposed at one or more angles relative to the planar surface <NUM> similar to the cavities 168a-<NUM> through 168a-<NUM> of <FIG>. Likewise, each cavity <NUM>-168a-<NUM> through <NUM>-168a-<NUM> comprises a prismatic shape similar to the cavities 168a-<NUM> through 168a-<NUM> of <FIG>. The light redirection cavities <NUM>-168a-<NUM> through <NUM>-168a-<NUM> are arranged partially spanning the planar surface 212a and the transition area <NUM>-201a. Redirection cavity <NUM>-168a-<NUM> is arranged only in the planar surface 212a, while redirection cavity <NUM>-168a-<NUM> partially spans the planar surface 212a, the transition area <NUM>-201a, and the transition area <NUM>-205a.

A plurality of wedge-shaped light extraction members 260a-<NUM>, 260a-<NUM>, and a sloped transition area <NUM>-201a are disposed between the planar portion 212a and the center line <NUM>, and extend between the coupling end surface <NUM> and the non-coupling end surface <NUM>. The transition area <NUM>-201a and the extraction members <NUM> direct light redirected by the cavities <NUM>-<NUM> out of the bottom surface <NUM> of the waveguide body <NUM>. Light is also directed outwardly through the surface <NUM> by the transition feature <NUM>-205a and a wedge-shaped extraction member <NUM> disposed at the non-coupling end <NUM>.

<FIG> shows an example cross-sectional geometry of the extraction members <NUM> and the bottom surface extraction features <NUM> as indicated in <FIG>. As previously discussed, the geometry of the extraction members <NUM> and extraction features <NUM> may be altered to manipulate the illumination pattern produced by the waveguide body <NUM>. In the embodiment of <FIG>, the wedge-shaped extraction features <NUM>, <NUM>-<NUM>, and <NUM> and the light redirection cavities <NUM>-<NUM> are arranged to develop an illumination pattern for wider street coverage when the optical assembly <NUM> is used in a streetlight application.

Referring now to <FIG>, the bottom surface <NUM> is substantially identical to the bottom surface <NUM> shown in <FIG>. Furthermore, similar to the waveguide body of <FIG>, outer planar surface <NUM> may be textured on the emission surface such that any light internally reflected within the outer planar surface <NUM> is extracted. However, in the embodiment of <FIG>, the inner recessed section <NUM> and the rib <NUM> are also textured. Texture on the emission surfaces of both the outer planar surface <NUM> and the inner recessed section <NUM> and rib <NUM> may aid in extracting any stray diffused light as well as providing additional color mixing.

Referring now to <FIG>, the top surface <NUM> of the waveguide body <NUM> is shown. The central section <NUM> of the waveguide body <NUM> is similar to the central section of the waveguide body of <FIG> except for the following differences. As with the previous embodiments, the central section <NUM> of the waveguide body <NUM> of <FIG> includes two side sections 208a, 208b that are preferably mirror images of one another. The side section 208a includes a first wedge-shaped light extraction member <NUM>-210a extending between the side wall 194a and a planar rectangular portion 212a. A transition area <NUM>-202a also extends between the side wall 194a and the planar rectangular portion 212a. The transition area <NUM>-202a may comprise a sloped surface <NUM>-<NUM> that may be polished, and/or may include faceting or scalloping on all or a portion of the sloped surface <NUM>-<NUM>, as seen in <FIG> in connection with that previously discussed embodiment.

As shown in <FIG>, each of the wedge-shaped light extraction members <NUM>-210a includes sloping light extraction surface <NUM>-210a-<NUM>, which is similar or identical to the sloped surface <NUM>-<NUM> of the transition area <NUM>-202a, that together direct light downwardly and out of the waveguide body <NUM>. In this embodiment, the transition area <NUM>-202a and the single wedge-shaped light extraction member <NUM>-210a are larger as compared to the wedge-shaped light extraction members <NUM>-<NUM> and <NUM>-<NUM> of <FIG> and <FIG>, respectively. Further, the sloped surface <NUM>-<NUM> of the transition area <NUM>-202a and the sloping light extraction surface <NUM>-210a-<NUM> of single wedge-shaped light extraction member <NUM>-210a have more gradual slopes as compared to the wedge-shaped light extraction members of other embodiments or the transition area <NUM>-205a and wedge-shaped light extraction member <NUM> of the end portion <NUM>. The gradual incline of the wedge-shaped light extraction member <NUM>-210a and the transition area <NUM>-202a are arranged to develop an illumination pattern that provides wider street coverage, as compared to the waveguide body of <FIG>.

A plurality of light redirection cavities <NUM>-<NUM> extend into the planar portion 212a. In the illustrated embodiment, there are seven cavities <NUM>-168a-<NUM> through <NUM>-168a-<NUM>. The cavities <NUM>-168a-<NUM> through <NUM>-168a-<NUM> are substantially or fully trapezoidal in cross-sectional shape as seen in <FIG>. The cavities <NUM>-<NUM> have base surfaces (<NUM>-168a-1a, <NUM>-168a-2a, etc.) nearest the planar surface <NUM> that are disposed at one or more angles relative to the planar surface <NUM>, similar to <FIG>. Remaining side surfaces defining each cavity <NUM>-<NUM> form a prismatic shape with the base surface associated therewith.

A plurality of wedge-shaped light extraction members 260a-<NUM>, 260a-<NUM>, and a sloped transition area <NUM>-201a are disposed between the planar portion 212a and the center line <NUM>, and extend between the coupling end surface <NUM> and the non-coupling end surface <NUM>. <FIG> shows an example cross-sectional geometry of the extraction members <NUM>-<NUM> and the bottom surface extraction features <NUM> as indicated in <FIG>. The transition area <NUM>-201a and the extraction features <NUM>-<NUM> direct light redirected by the cavities <NUM>-<NUM> out of the bottom surface <NUM> of the waveguide body <NUM>. Light is also directed outwardly through the surface <NUM> by the transition feature <NUM>-<NUM> and the wedge-shaped extraction member <NUM>.

Referring still to <FIG>, the transition surface <NUM>-<NUM> is smooth in the depicted embodiment. Further, the transition area <NUM>-202a includes a triangular light redirecting cavity <NUM>. The triangular light redirecting cavity 236a is formed by a vertical triangle cut into the transition area <NUM>-202a. The triangular light redirecting cavity 236a is configured as a refracting optic that assists in developing an illumination pattern for covering a relatively wider street. Referring ahead to <FIG>, the arrows therein show the general refractive property of the triangular redirecting cavity 236a. Thus, additional light is directed along the y-dimension of the waveguide body <NUM> and a narrower illumination pattern is effectuated. The triangular light redirection cavity 236a has an equilateral triangular shape and is disposed such that a side surface <NUM> is parallel to the planar end surface <NUM> and a point <NUM> opposite the side surface <NUM> is disposed between the coupling cavities <NUM> and the transition area <NUM>-202a. The coupling geometry of <FIG> is similar to that shown in <FIG> and provides improved color mixing as well as aids in developing an illumination pattern that adequately illuminates a location relatively far from the location of the optical assembly <NUM> when utilized in a streetlight application. In this embodiment, the light redirection cavities <NUM> are arranged, in conjunction with the wedge-shaped light extraction members <NUM>, to develop an illumination pattern that provides wider street coverage when compared to the embodiment of <FIG>.

Referring now to <FIG>, the bottom surface <NUM> is substantially identical to the bottom surface <NUM> shown in <FIG> and has texturing on surfaces similar to the embodiment of <FIG>. It may be desirable for all light to be extracted from the luminaire 100a, and thus, outer planar surface <NUM> (shaded in the embodiment depicted by <FIG>) may be textured on the emission surface <NUM> such that any light internally reflected within the outer planar surface <NUM> is extracted. Further, the texture may assist in diffusion of any stray light internally reflected within the outer planar surface <NUM>.

In some embodiments, the waveguide body includes a plurality of redirection features and a plurality of extraction features, wherein the redirection features are relatively smaller than the extraction features. In other embodiments, at least one redirection feature has a linear extent in a first direction and at least one extraction feature has a linear extent in a second direction different from the first direction. In further embodiments, the linear extent of at least one extraction feature extends the entire length or width of the waveguide, and the linear extent of the at least one redirection feature is smaller than the linear extent of the extraction feature.

In still further embodiments, extraction features are disposed on a bottom surface of the waveguide and redirection features extend into an upper surface of the waveguide opposite the bottom surface. In other embodiments, the redirection features are disposed at an angle relative to an extent (in the x-dimension) of a plurality of coupling cavities and the extraction features are disposed perpendicular and/or parallel to the extent (in the x-dimension) of the plurality of coupling cavities. Further still, the waveguide dimensions are exemplary only, it being understood that one or more dimensions could be varied. For example, the dimensions can all be scaled together or separately to arrive at a larger or smaller waveguide body, if desired. While a uniform distribution of light may be desired in certain embodiments, other distributions of light may be contemplated and obtained using different arrays of extraction features.

Other embodiments of the disclosure including all of the possible different and various combinations of the individual features of each of the foregoing embodiments and examples are specifically included herein. Any one of the light redirection features could be used in an embodiment, possibly in combination with any one of the light extraction features of any embodiment. Similarly, any one of the light extraction features could be used in an embodiment, possibly in combination with any one of the light redirection features of any embodiment. Thus, for example, a luminaire incorporating a waveguide of one of the disclosed shapes may include extraction features of the same or a different shape, and the extraction features may be symmetric or asymmetric, the luminaire may have combinations of features from each of the disclosed embodiments, etc. without departing from the scope of the invention.

The spacing, number, size, and geometry of extraction features <NUM> determine the mixing and distribution of light in the waveguide body <NUM> and light exiting therefrom. In the illustrated embodiment, the extraction features <NUM> comprise a series of ridges separated by intervening troughs at least some of which define one or more inverted V-shapes in cross section, as seen in the FIGS. Also, at least one (and perhaps more or all) of the bottom surface extraction features <NUM>, top surface extraction members or any, or all of the other extraction features disclosed herein may be continuous (i.e., it extends in a continuous manner), while any remaining extraction features may comprise continuous or discontinuous ridges (i.e., partial linear and/or nonlinear features extending continuously or discontinuously) separated by intervening troughs.

If desired, inflections or other surface features may be provided in any of the extraction features disclosed herein. Still further, for example, as seen in the illustrated embodiment, all of the extraction features <NUM> are symmetric with respect to the center line <NUM> of the waveguide body <NUM>, although this need not be the case. Further, one or more of the extraction features <NUM> may have a texturing on the top surface <NUM> of the waveguide body <NUM>, or the extraction features may be smooth and polished. In any of the embodiments described herein, the top surface <NUM> of the waveguide body <NUM> may be textured in whole or in part, or the top surface <NUM> may be smooth or polished in whole or in part.

In addition to the foregoing, the waveguide body <NUM> and any other waveguide body disclosed herein may be tapered in an overall sense from the coupling cavities <NUM> to the end surface in that there is less material at the general location of the non-coupling end surface <NUM> than at portions adjacent the coupling cavities <NUM>. Such tapering may be effectuated by providing extraction features that become deeper and/or more widely separated with distance from the coupling cavities <NUM>. The tapering maximizes the possibility that substantially all the light introduced into the waveguide body <NUM> is extracted over a single pass of the light therethrough. This results in substantially all of the light striking the outward surfaces of the extraction features <NUM>, which surfaces are carefully controlled so that the extraction of light is also carefully controlled. The combination of tapering with the arrangement of extraction features result in improved color mixing with minimum waveguide thickness and excellent control over the emitted light.

The driver circuit <NUM> may be adjustable either during assembly of the luminaire <NUM>, 100a or thereafter to limit/adjust electrical operating parameter(s) thereof, as necessary or desirable. For example, a programmable element of the driver circuit <NUM> may be programmed before or during assembly of the luminaire <NUM>, 100a or thereafter to determine the operational power output of the driver circuit <NUM> to one or more strings of LED elements <NUM>. A different adjustment methodology/apparatus may be used to modify the operation of the luminaire <NUM>, 100a as desired.

In addition, an adjustable dimming control device may be provided inside the housing <NUM> and outside the reflective enclosure member <NUM> that houses the circuit board <NUM>. The adjustable control device may be interconnected with a NEMA ambient light sensor and/or dimming leads of the driver circuit and may control the driver circuit <NUM>. The adjustable dimming control device may include a resistive network and a wiper that is movable to various points in the resistive network. An installer may operate (i.e., turn) an adjustment knob or another adjustment apparatus of the control device operatively connected to the wiper to a position that causes the resistive network to develop a signal that commands the output brightness of the luminaire <NUM> to be limited to no more than a particular level or magnitude, even if the sensor is commanding a luminaire brightness greater than the limited level or magnitude.

If necessary or desirable, the volume of the reflective enclosure member <NUM> may be increased or decreased to properly accommodate the driver circuit <NUM> and to permit the driver circuit to operate with adequate cooling. The details of the parts forming the reflective enclosure member <NUM> may be varied as desired to minimize material while providing adequate strength.

Further, any of the embodiments disclosed herein may include a power circuit having a buck regulator, a boost regulator, a buck-boost regulator, a SEPIC power supply, or the like, and may comprise a driver circuit as disclosed in <CIT> (Cree docket no. P2276US1, attorney docket no. <NUM>-<NUM>) or <CIT> (Cree docket no. P2291US1, attorney docket no. <NUM>-<NUM>). The circuit may further be used with light control circuitry that controls color temperature of any of the embodiments disclosed herein in accordance with user input such as disclosed in <CIT> (Cree docket no.

Any of the embodiments disclosed herein may include one or more communication components forming a part of the light control circuitry, such as an RF antenna that senses RF energy. The communication components may be included, for example, to allow the luminaire to communicate with other luminaires and/or with an external wireless controller, such as disclosed in <CIT>, entitled "Lighting Fixture for Distributed Control" or <CIT>, entitled "Enhanced Network Lighting" both owned by the assignee of the present application. More generally, the control circuitry includes at least one of a network component, an RF component, a control component, and a sensor. The sensor, such as a knob-shaped sensor, may provide an indication of ambient lighting levels thereto and/or occupancy within the room or illuminated area. Such sensor may be integrated into the light control circuitry.

As noted above, any of the embodiments disclosed herein can be used in many different applications, for example, a parking lot light, a roadway light, a light that produces a wall washing effect, a light usable in a large structure, such as a warehouse, an arena, a downlight, etc. A luminaire as disclosed herein is particularly adapted to develop high intensity light greater than <NUM> lumens, and more particularly greater than <NUM>,<NUM> lumens, and can even be configured to develop <NUM>,<NUM> or more lumens by adding LED elements and, possibly, other similar, identical or different waveguide bodies with associated LEDs in a luminaire.

The placement of multiple LED element(s) and the optics of the waveguide bodies overlay the illumination from each LED element onto each other, which further helps color mixing while maintaining a desired photometric distribution. If necessary or desirable, color mixing may be enhanced by using any of the structures or cavities disclosed in co-pending applications <CIT>, entitled "Optical Waveguides and Luminaires Incorporating Same," (Cree docket no. P2126US1), <CIT>, entitled "Waveguide Bodies Including Redirection Features and Methods of Producing Same," (Cree docket no. P2130US1), <CIT>, entitled "Luminaire Using Waveguide Bodies and Optical Elements" (Cree docket no. P2131US1), and <CIT>, entitled "Optical Waveguide and Lamp Including Same" (Cree docket no. P2151US1), owned by the assignee of the present application and filed herewith. If desired, any of the features disclosed in co-pending <CIT> and/or <CIT> (Cree docket nos. P1961US1 and P2025US1, respectively), may be used in the luminaire <NUM> as desired.

Further, any LED chip arrangement and/or orientation as disclosed in <CIT>, entitled "Luminaire Using Waveguide Bodies and Optical Elements" (Cree docket no. P2131US1), owned by the assignee of the present application, may be used in the devices disclosed herein. Where two LED elements are used in each light coupling cavity (as in the illustrated embodiments), it may be desired to position the LEDs elements within or adjacent the coupling cavity along a common vertical axis or the LED elements may have different angular orientations, as desired. The orientation, arrangement, and position of the LEDs may be different or identical in each waveguide body section of a waveguide as desired. Still further, each light coupling cavity may be cylindrical or non-cylindrical and may have a substantially flat shape, a segmented shape, an inclined shape to direct light out a particular side of the waveguide body, etc..

When one uses a relatively small light source which emits into a broad (e.g., Lambertian) angular distribution (common for LED-based light sources), the conservation of etendue, as generally understood in the art, requires an optical system having a large emission area to achieve an asymmetric angular light distribution. In the case of parabolic reflectors, a large optic is thus generally required to achieve high levels of collimation. In order to achieve a large emission area in a more compact design, the prior art has relied on the use of Fresnel lenses, which utilize refractive optical surfaces to direct and collimate the light. Fresnel lenses, however, are generally planar in nature, and are therefore not well suited to re-directing high-angle light emitted by the source, leading to a loss in optical efficiency. In contrast, in the present invention, light is coupled into the optic, where primarily TIR is used for re-direction and light distribution. This coupling allows the full range of angular emission from the source, including high-angle light, to be re-directed, resulting in higher optical efficiency in a more compact form factor.

While specific coupling features and extraction feature parameters including shapes, sizes, locations, orientations relative to a light source, materials, etc. are disclosed as embodiments herein, the present invention is not limited to the disclosed embodiments, inasmuch as various combinations and all permutations of such parameters are also specifically contemplated herein. Any of the features such as various shaped coupling cavities, LED elements, redirection features, extraction features, etc. described and/or claimed in <CIT>, (Cree docket no. P1946US1), <CIT>, (Cree docket no. P1961US1), <CIT>, entitled "Optical Waveguide Body" (Cree docket no. P1968US1), <CIT>, (Cree docket no. P2025US1), <CIT>, entitled "Optical Waveguides and Luminaires Incorporating Same", (Cree docket no. P2126US1), <CIT>, entitled "Waveguide Bodies Including Redirection Features and Methods of Producing Same," (Cree docket no. P2130US1), <CIT>, entitled "Luminaire Using Waveguide Bodies and Optical Elements" (Cree docket no. P2131US1), <CIT>, entitled "Simplified Low Profile Module with Light Guide for Pendant, Surface Mount, Wall Mount and Stand Alone Luminaires" (Cree docket no. P2141US1), and <CIT>, entitled "Optical Waveguide and Lamp Including Same" (Cree docket no. P2151US1), International Application No. <CIT>, entitled "Optical Waveguides and Luminaires Incorporating Same" (Cree docket No. P2126WO), and International Application No. <CIT>, entitled "Optical Waveguide Body" (Cree docket No. P2225WO), owned by the assignee of the present application may be used in a luminaire, either alone or in combination with one or more additional elements, or in varying combination(s) to obtain light mixing and/or a desired light output distribution. Thus, for example, any of the luminaires disclosed herein disclosed herein may include one or more waveguide bodies including coupling features, one or more light redirection features, one or more extraction features or optics, and/or particular waveguide body shapes and/or configurations as disclosed in such applications, as necessary or desirable. Other waveguide body form factors and luminaires incorporating such waveguide bodies are also contemplated.

At least some of the luminaires disclosed herein are particularly adapted for use in installations, such as outdoor products (e.g., streetlights, high-bay lights, canopy lights) preferably requiring a total luminaire output of at least about <NUM>,<NUM> lumens or greater, and, in some embodiments, a total luminaire output of up to about <NUM>,<NUM> lumens, and, in other embodiments, a total lumen output from about <NUM>,<NUM> lumens to about <NUM>,<NUM> lumens. Further, the luminaires disclosed herein preferably develop a color temperature of between about <NUM> degrees Kelvin and about <NUM> degrees Kelvin, and more preferably between about <NUM> degrees Kelvin and about <NUM> degrees Kelvin, and, in some embodiments, between about <NUM>,<NUM> degrees Kelvin and about <NUM>,<NUM> degrees Kelvin. Also, at least some of the luminaires disclosed herein preferably exhibit an efficacy of at least about <NUM> lumens per watt, and more preferably at least about <NUM> lumens per watt, and more preferably, at least about <NUM> lumens per watt, and more preferably, about <NUM> lumens per watt. Also, at least some of the luminaires disclosed herein exhibit an efficacy of about <NUM> lumens per watt or greater. Further, at least some of the waveguide bodies used in the luminaires disclosed herein preferably exhibit an overall efficiency (i.e., light extracted out of the waveguide body divided by light injected into the waveguide body) of at least about <NUM> percent. A color rendition index (CRI) of at least about <NUM> is preferably attained by at least some of the luminaires disclosed herein, with a CRI of at least about <NUM> being more preferable. The luminaires disclosed herein produce a scotopic to photopic (S/P) ratio of at least <NUM>, preferably at least <NUM>. Any desired form factor and particular output light distribution, including up and down light distributions or up only or down only distributions, etc. may be achieved.

Embodiments disclosed herein are capable of complying with improved operational standards as compared to the prior art as follows:.

In certain embodiments, the waveguide bodies used in the luminaires disclosed herein may generally taper from a central portion to an outside edge thereof so that substantially all light is extracted during a single pass of each light ray from the LED element(s) to the outer edge of the waveguide body. This extraction strategy maximizes the incidence of light rays impinging on an outer side of each extraction feature and being reflected out a surface (or surfaces) of the waveguide body in a controlled manner, as opposed to striking other surfaces at an angle greater than the critical angle and escaping as uncontrolled light. The outer sides of the extraction features are accurately formed so that control is maintained over the direction of extracted light, thereby allowing a high degree of collimation. Still further, the waveguide body is very low profile, leaving more room for heat exchanger structures, driver components, and the like in the luminaire. Also, glare is reduced as compared with other lamps using LED light sources because light is directed outwardly in the waveguide body while being extracted from the waveguide body by the extraction features such that the resulting emitted light is substantially mixed and substantially uniformly distributed throughout the beam angle. The result is a light distribution that is pleasing and particularly useful for general illumination and other purposes using a light source, such as one or more LED element(s).

In some embodiments, one may wish to control the light rays such that at least some of the rays are collimated, but in the same or other embodiments, one may also wish to control other or all of the light rays to increase the angular dispersion thereof so that such light is not collimated. In some embodiments, one might wish to collimate to narrow ranges, while in other cases, one might wish to undertake the opposite. Any of these conditions may be satisfied by the luminaires utilizing waveguide bodies disclosed herein through appropriate modification thereof.

The use of the terms "a" and "an" and "the" and similar references in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure.

Claim 1:
An optical waveguide, comprising:
a plurality of coupling cavities (<NUM>) for directing light into a waveguide body (<NUM>) spaced from a particular point,
LED elements (<NUM>) disposed within or adjacent the coupling cavities (<NUM>), wherein each LED element (<NUM>) is a single LED or comprises multiple LEDs,
wherein the optical waveguide extends in an x-dimension and a y-dimension orthogonal to the x-dimension, the x-dimension being the width of the waveguide body (<NUM>),
wherein each coupling cavity (<NUM>) is defined by a coupling surface (<NUM>), each coupling surface (<NUM>) including spaced bumps or other features that protrude at points along a z-dimension normal to an x-y plane in such a way as to delineate discrete coupling cavities (<NUM>), each coupling cavity (<NUM>) provided for and associated with an individual LED among the LED elements (<NUM>);
the waveguide body being bisected in the x-dimension by a line extending in the y-dimension and crossing the particular point to form first and second portions of the waveguide body on opposite sides of the line, the coupling cavities (<NUM>) arranged along the waveguide in the x-dimension,
a first plurality of coupling cavities (<NUM>) disposed on one of the first and second portions and a second plurality of coupling cavities (<NUM>) disposed on another of the first and second portions,
characterized in that:
each of the coupling cavities (<NUM>) comprises a surface with a shape that is at least partially parabolic;
each of the coupling cavities (<NUM>) comprises a dimension that varies with the distance from the particular point,
wherein the dimension that varies with distance from the particular point is a focal length of each coupling cavity (<NUM>), and
wherein coupling cavities having the shortest focal length are proximal the particular point.