Patent Application
20130044475
The present disclosure is directed generally to the use of light sources. More particularly the present disclosure is directed to lighting structures that include reflective and refractive elements that can be used to distribute light from one or more light sources in desired directions.
Different strategies have been designed to provide uniform and efficient light distribution over a given area. For example, display cases are commonly used in retail applications, such as the refrigerated cases in supermarkets and convenience stores, to display merchandise and are commonly arranged into banks of shelving displays or showcase displays for holding goods. Typically, such display cases are illuminated by fluorescent light fixtures. While providing certain benefits over incandescent lighting, fluorescent lights themselves have inherent power and maintenance requirements and related costs. Fluorescent lights also contain mercury causing substantial environmental concerns and costs.
Certain techniques have been employed to install alternate sources of lighting in place of fluorescent lights. Such techniques typically require contemporaneous altering of the structural support adjacent to the fluorescent light fixtures, such as by drilling holes. For applications including refrigerated food and beverage displays, such techniques can lead to unnecessary wasted cooling energy, excess labor, and possibly spoiling of the refrigerated items themselves as well as costs related to each.
Light emitting diodes (LEDs) have been used in various applications where incandescent or fluorescent lights have been used. Because individual LEDs are essentially point light sources, as opposed to continuous elements, such as incandescent and fluorescent lights, lighting uniformity has proven challenging to achieve for many applications.
The present disclosure is directed to lighting structures including refractive and/or reflective structures that can provide or distribute lighting for a given area with high uniformity and efficiency. The lighting structures can include a reflector, configured to reflect light from an adjacent light source, the reflector defining one or more apertures configured to allow light from the light source to pass therethrough. The structures can be used to distribute light from one or more light sources for lighting target areas with a desired light distribution. Other aspects, embodiments, and details of the present disclosure will be apparent from the following description when read together with the accompanying drawings.
The lighting structures can be included in light strips or luminaires. Such light strips or luminaires can be utilized in place of fluorescent lights and can facilitate quick and easy retrofit for previous fluorescent lighting applications. The disclosed techniques and systems (including components and structures) can be particularly useful when employing one or more LEDs or the like as light sources.
Light distribution structures according to the present disclosure can include a refractive element and a reflective element.
An exemplary embodiment can include a luminaire including any of the previously mentioned reflective elements or reflectors may be configured to reflect a first portion of light received from a light source in one or more desired directions and to allow a second portion of light from the light source to pass therethrough in one or more desired directions; and a refractive element configured to receive one or both of the first and second portions of light and transmit both in desired directions.
Another exemplary embodiment can include a luminaire having a light source for emitting light, a reflector having a first side and a second side, the reflector configured and situated such that a first portion of the light emitted by the light source passes through the reflector from the first side to the second side, and a second portion of the light emitted by the light source is reflected by the first side of the reflector. The luminaire can be configured such the first portion of light emitted by the light source passes through an aperture defined in the reflector. The reflector may optionally be generally V-shaped and the luminaire may be configured such that the light source is situated adjacent to the vertex of the V-shaped reflector. The reflector may optionally be generally V-shaped and the luminaire and the first portion of light emitted by the light source may be configured such that the first portion of light passes through an aperture defined approximately at the vertex of the V-shaped reflector. The luminaire may be configured such that a third portion of light emitted by the light source does not pass through the reflector and is not reflected by the first side of the reflector. The luminaire may optionally comprise a second light source wherein a first portion of light emitted by the second light source passes through the aperture defined in the reflector. The luminaire may also optionally comprise a refractor lens having a central lens portion configured to receive at least a portion of the first portion of light emitted by the light source and the central lens portion may optionally be contoured to refract light.
Aspects and embodiments of the present disclosure may be more fully understood from the following description when read together with the accompanying drawings, which are to be regarded as illustrative in nature, and not as limiting. The drawings are not necessarily to scale, emphasis instead being placed on the principles of the disclosure. In the drawings:
The embodiments depicted in the drawing are merely illustrative. Variations of the embodiments shown in the drawings, including embodiments described herein, but not depicted in the drawings, may be envisioned and practiced within the scope of the present disclosure.
Aspects and embodiments of the present disclosure provide luminaires and lighting structures. Luminaires according to the present disclosure can be used for new installations or to retro-fit existing lighting assemblies and applications, such as those that utilize fluorescent lighting. Use of such lighting techniques can afford reduced energy and maintenance as well as reduced installation time and costs when compared to existing techniques.
In exemplary embodiments, alternative light sources to fluorescent lights may be utilized. While the preferred embodiment employs LEDs as light sources, other light sources may also be employed or alternatively used within the scope of the present disclosure. By way of example only, other light sources such as plasma light sources may be used. Further, the term “LEDs” is intended to refer to all types of light emitting diodes including organic light emitting diodes or “OLEDs”.
While the luminaire depicted in the Figures is generally applicable to any application that would benefit from strip lighting, it is well-suited, in one example, for application to display cases where the luminaire can be mounted to various of the elongated structural elements of the display case to be hidden from the view of customers viewing items in the display case. One exemplary application is refrigerated food cases such as those commonly found in supermarkets and convenience stores. The depicted luminaire lends itself to application in food cases because its elongated structure facilitates mounting to mullions between doors permitting access to the food case. Such refrigerated cases, can include cases for chilled foods and/or drinks, as well as those used to display frozen foods. Other embodiments may be particularly well-suited for use in display cases for displaying non-food items, e.g., those used to display merchandise goods such as jewelry, watches, and the like. Use in such non-food display cases is advantageous because of the luminaires ability to be mounted to various of the elongated structural components of the display case to illuminate the display case while remaining at least mostly hidden from view of those persons viewing items in the display case. As will be discussed below, the reflector of the present disclosure, while elongated, is applicable to other luminaires such as by using multiple of these reflectors to guide the light from various matrices of light sources.
In operation while the one or more light sources 108 of the luminaire 100 depicted in
Light emanating from the one or more light sources travels though the refractive element in accordance with Snell's law. For ease of comprehension, light ray traces in the area indicated at reference numeral 3 indicates light passing through the depicted aperture 208 then the lens 206. Light ray traces in the two areas indicated at reference numeral 2, indicates light emanating from the one or more light sources 204 and passing laterally through the lens either directly from the light source 204 or after reflecting from the reflective element 202.
The lens or refractive element 206 may include a portion 206a that is configured to receive a portion of light from the one or more light sources 204 passing through the one or more apertures 208.
The reflector mounting structure 210, comprises the same configuration as the reflector mounting structure 106 shown in
Frame 214 may have any desired shape. For example, frame 214 preferably includes one or more arms forming channels (214a, 214b) having a partially circular cross-section configured to receive fasteners such as screws, dowels, pins, or the like to assist with assembly or mounting of the luminaire 200. Frame 214 also preferably includes one or more arms (214c-214e), that are configured to receive and/or contact one or more respective portions of the luminaire 200. For example, in the embodiment depicted in
Continuing with the description of
With further reference to
Each aperture 305 may be configured (e.g., sized and/or shaped) as desired. For example, a single aperture 305 may be sized to have a length (measured along the vertex of the reflector 304) that is or is substantially the length of PCB 312 so as to provide an opening at the vertex of the reflector 304 at each light source along the length of the PCB 312. In other embodiments, multiple apertures (a plurality of) 305 may be disposed in a desired configuration, e.g., linearly with a constant or varying linear density (e.g., one every foot, one every light source, one every two light sources, etc.). Each individual aperture 305 may have a shape (e.g., of its perimeter) that is selected as desired. For example, an aperture may be elliptical in shape with any degree of eccentricity, circular, rectangular, irregular (any shape) square, triangular, etc.
In exemplary embodiments, the central lens portion 303 of refractor 302 may be positioned to receive light from a light source 308 by way of aperture 305. The luminaire 300A may be configured such that all light passing through the aperture 305 passes through the central lens portion 303. Alternatively, luminaire 300A may be configured such that only a portion of the light passing through the aperture 305 passes through the central lens portion 303. In yet a further alternative embodiment, the luminaire may comprise a refractor 302 with no central lens portion 303, in which case the refractor 302 is of the substantially the same thickness in all portions through which light from the light source 308 travels. Refractor 302 may have one or more lateral faces 307, as shown, which may have varying thicknesses to direct the light passing therethrough, or be of constant thickness to serve primarily as protection for the elements of the luminaire 300A. Refractor 302 may optionally have inwardly directed members 318, as shown. In one embodiment not depicted, optional inwardly directed member 318 may be configured so as to clamp the PCB 312 to the frame 314 when the refractor 302 is connected to the frame 314 as depicted in
Refractor 302 may include a central face 315 in which the central lens portion 303 resided, if a central lens portion 303 is present. Central face 315 may be relatively or substantially flat in some embodiments, though it may comprise one or more curvatures or other shapes. The central face 315 may have a desired width, shown by “a,” and may be of any length suitable for the luminaire 300A and its application. For example, the length of face 315 may be 3 ft., 6 ft., 9 ft., etc. In some embodiments, central face 315 may have a diffusive surface 316 on the interior or exterior thereof, which may facilitate uniformity of light intensity and distribution. The diffusive surface 316 can span the entirety of central face 315 or portions of central face 315 as needed, e.g., as indicated by width “b” in the
In operation, light source 308 can produce light, which may emanate from the light source 308 in a three-dimensional distribution pattern, e.g., a hemisphere of 271 steradians of solid angle, or a cone of other given included solid angle, etc. Of the light constituting this distribution, some may travel directly out of the refracting element 302, for example, through lateral face 307, as shown by representative rav trace R1. Some of the light from the light source 308 may be reflected by reflective element 304 and then pass through refractive element 302 as shown by representative ray trace R2. Still, another portion of the light from light source 308 may pass through aperture 305 and then through refractive element 302, e.g., through contoured portion 303, as shown by representative ray trace R3. Ray traces R1-R3 are merely representative, and other optical paths may occur, e.g., ones including total internal reflection in accordance with Snell's law.
Refractor 302 may be made from any suitable transparent, substantially transparent, and/or translucent material, e.g., glass, Lexan, or acrylic such as sold under the trade name Optix ® CA-1000E, or suitable functional equivalent. The material used for the refractor 302 may have any suitable clarity. In exemplary embodiments, the material may be about 85% transmissive, though higher values, e.g., 90% or higher, may be preferred. The diffusive surface 316 or the central face 315 and exemplary materials therefore are discussed above. Any suitable reflective material may be used for reflector 304. Examples include, but are not limited to, specular aluminum, chromed steel, aluminized or aluminum-coated plastic, painted plastic, and the like. In exemplary embodiments, a specular aluminum sheet is used that is about 95% reflective; of course, other values of reflectivity (e.g., 70%, 85%, 90% or thereabouts) may be used or implemented for a reflective element. Alanod Miro—4400 GP is considered suitable. If the reflector 304 is comprises of a metal, the reflector can be constructed by one or more stamping operations to form the apertures 305 and one or more bending operations to form the desired V-shape. It is further noted that the reflector 304 shape need not be an absolute V. Rather various variations and deviations from the absolute V, such as curved legs extending from the vertex, are contemplated.
In an exemplary embodiment, light source(s) 308 may include one or more LEDs suitable for the light distribution and intensity necessary for the application. The light sources 308 could be LEDs made commercially available by Osram Opto Semiconductor, Model Oslon LUW CP7P-LXLY-7P7E. Other suitable lights sources 308 may include, but are not limited to, Cree XPEWHT-01-0000-00EC, Philips LumiLEDS Rebel LXML-PWN1-0100, or suitable equivalent. The length (e.g., into or out of the plane of
In exemplary embodiments, luminaire 300A may have a rectangular shape in plan view and may be configured for retrofitting into a lighting application that previously included fluorescent lighting. Of course, luminaire 300A may have other shapes in plan view, e.g., circular, oval, square, etc.
For use in illuminating a desired area, the luminaires of the present disclosure may be mounted to a structure or surface by any suitable mounting devices, structures, fasteners, or the like.
For operation, in some applications, a power cable/chord from the luminaire 300B may be run through a hole (e.g., 332) in the mounting bracket 301 out the back and through a hole formed into an underlying structures such as a cooler mullion to which the luminaire 300B is to be mounted. The other end (not shown) of the luminaire 300B may optionally include a hole, e.g., a breather hole for venting the interior of the fixture. The cooler mullion can act as a passageway for the power cable and possible mounting location of a related power supply. The luminaire 300B may be attached (e.g., screwed) into place, e.g., on the cooler mullion, top and bottom. The end cap (e.g., a molded plastic cap) 303 may be snapped over this mounting bracket 301 to hide the screws, cables, etc. The back of the luminaire 300B and the cap 303 may rest flush against an underlying structure, e.g., cooler mullion. In this way, all potential crevices may be hidden or minimized, e.g., for NSF compliance.
For luminaire 400, a number of design parameters (c-j) are shown, which may be selected as desired for various applications. The design parameters shown include the following: (c)—the distance or height between the top of the refractive element 402 at the central face 415 and the optical center 408; (d)—the distance or height between the lowest portion of the curved surface 403a of the central lens portion 403; (e)—the distance or height between the optical center of the light source 408 and the proximal portion of the apex of the reflector 404 at the aperture 405; (f)—the thickness of the central face 415; (g)—angle between the faces 404a of the reflector 404 and the horizontal reference plane; (h)—the distance or height between the optical center of the light source 408 and the distal or top portion of the optical source housing, e.g., LED package; (i)—angular range of rays emanating from aperture (either solid angle or 2D angle); (j)—distance or diameter across trench or circle formed by the curved surface 403a of the central lens portion 403; and (k)—distance or length of lateral reflective surface(s) 404a.
In an exemplary embodiment, luminaire 400 as shown in
As shown, luminaire 700 may include a refractor 702 and a reflector 704. Refractor 702 may include a central lens portion 703 that has a profiled surface 703a. Reflector 704 may include one or more lateral reflective faces 704a. The included angle between the lateral reflective faces 704a may be selected as desired for the sought light distribution. For example, the angle may be about 100 degrees, about 90 degrees, about 95 degrees, about 110 degrees, 80 degrees, about 105 degrees, etc. Luminaire 700 may also include a frame element 706 with one or more secondary reflective surfaces 706a, as indicated. Frame element 706 may also have a base 706b, as shown. Reflective element 704 may include one or more apertures 707. Aperture(s) 707 may be configured adjacent to, and pass or receive light from, one or more light sources 708. Light source(s) 708 may be positioned on a support surface 712, e.g., a PCB.
With continued reference to
As further shown in
In exemplary embodiments, luminaire 700 has a rectangular shape in plan view and may be configured for retrofitting into a lighting application that previously included fluorescent lighting. Of course, luminaire 700 may have other shapes in plan view, e.g., circular, oval, square, etc.
In an exemplary embodiment, the lateral faces 104a are 0.517 inches long, the viewing angle is 7 degrees, base 706b is 1.136 inches wide, the secondary reflective surfaces 706a have a radius of curvature of 1.250 inches, and overall frame width is 2.821 inches, with a height to the top of the frame of 0.490 inches, while the overall height of the luminaire is 0.635 inches.
In another exemplary embodiment, luminaire 700 as shown in
The LEDs of this exemplary embodiment can be of any kind, color (e.g., emitting any color or white light or mixture of colors and white light as the intended lighting arrangement requires) and luminance capacity or intensity, preferably in the visible spectrum. Color selection can be made as the intended lighting arrangement requires. In accordance with the present disclosure, LEDs can comprise any semiconductor configuration and material or combination (alloy) that produce the intended array of color or colors. The LEDs can have a refractive optic built-in with the LED or placed over the LED, or no refractive optic; and can alternatively, or also, have a surrounding reflector, e.g., that re-directs low-angle and mid-angle LED light outwardly. In one suitable embodiment, the LEDs are white LEDs each comprising a gallium nitride (GaN)-based light emitting semiconductor device coupled to a coating containing one or more phosphors. The GaN-based semiconductor device can emit light in the blue and/or ultraviolet range, and excites the phosphor coating to produce longer wavelength light. The combined light output can approximate a white light output. For example, a GaN-based semiconductor device generating blue light can be combined with a yellow phosphor to produce white light. Alternatively, a GaN-based semiconductor device generating ultraviolet light can be combined with red, green, and blue phosphors in a ratio and arrangement that produces white light (or another desired color). In yet another suitable embodiment, colored LEDs are used, such are phosphide-based semiconductor devices emitting red or green light, in which case the LED assembly produces light of the corresponding color. In still yet another suitable embodiment, the LED light board may include red, green, and blue LEDs distributed on the printed circuit board in a selected pattern to produce light of a selected color using a red-green-blue (RGB) color composition arrangement. In this latter exemplary embodiment, the LED light board can be configured to emit a selectable color by selective operation of the red, green, and blue LEDs at selected optical intensities. Clusters of different kinds and colors of LED is also contemplated to obtain the benefits of blending their output.
Each PCB, e.g., 212 of
In exemplary embodiments, a lens or refractive element may be made of an extrusion of polycarbonate or acrylic. Such polycarbonate or other plastic may be selected as desired and may possess a desired degree of transparency (and, therefore, opaqueness) and may have a desired color.
In further embodiments, the formation of at least one support member can include forming a circuit board supporting face in the support member that is configured and arranged to support the circuit board (and attached light sources) in a desired orientation, e.g., as when the related assembly is placed in a retrofit application. A visual cutoff shield may also be mounted to a support member for some applications.
Accordingly, lighting assemblies and luminaires according to the present disclosure can distribute light from one or more light sources in desired ways. Exemplary embodiments of lighting techniques according to the present disclosure can be used to retro-fit existing lighting assemblies and applications that were initially constructed to utilize fluorescent lighting. Such lighting according to the present disclosure can afford reduced energy, maintenance, and installation costs, as well as reduced installation time when compared to existing techniques. As described previously, exemplary embodiments of the present disclosure may utilize LEDs as light sources.
While certain embodiments have been described herein, it will be understood by one skilled in the art that the methods, systems, and apparatus of the present disclosure may be embodied in other specific forms without departing from the spirit thereof. For example, while aspects and embodiments herein have been described in the context of retrofit applications for refrigerated display cases, the present disclosure is not limited to such; for example, embodiments of the present disclosure may be utilized generally for any light distribution applications.
Accordingly, the embodiments described herein, and as claimed in the attached claims, are to be considered in all respects as illustrative of the present disclosure and not restrictive.
