The present disclosure relates generally to the use of light sources, and more particularly to luminaires and methods of retrofitting applications previously using fluorescent lighting, such as refrigerated display cases. The luminaires and methods of the disclosure are particularly well suited for employing light emitting diodes (LEDs) as light sources.
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 are currently being used 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.
What is currently lacking, therefore, are lighting systems and installation techniques that provide lighting with reduced power, installation, and maintenance costs compared with fluorescent lighting, particularly for retail goods displays and cases, including refrigerated cases, such as, for example, a retrofit for previous fluorescent lighting assemblies that minimizes replacement and installment costs and downtime of the display or case.
The present disclosure is directed to lighting structures, including light strips or luminaires, and methods, in which alternative light sources are utilized in place of fluorescent lights and that 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 as light sources.
An aspect of the present disclosure encompasses light source assemblies utilizing a strip with one or more light sources mounted on a support. The support can comprise more than one support member, such as mating pairs of complementary support members. The support can be attached to one or more brackets that are configured and arranged to fit with or connect to previously installed fluorescent light fixtures or mounting assemblies. For example, the brackets can snap into spring lampholder snap brackets of a previously installed fluorescent light assembly. One or more offset brackets can be used to move the support and light source(s) to a desired location, e.g., out of alignment with a centerline of the pre-existing snap brackets to reduce direct visibility of the support members and/or the light sources. Alternatively, the support can be held by a bracket implemented with a tab and/or set screw used to slip into a hole such as one pre-existing from a fluorescent lampholder.
Another aspect of the present disclosure encompasses related methods for manufacturing LED light strip assemblies or portions thereof. For such manufacturing methods, a light strip of LEDs can be affixed to one or more support members. Each support member can be positioned on a supporting surface so that each LED light strip is substantially in a horizontal position. A lens can be formed (e.g., poured) on each LED, or along an entire circuit board, while the circuit board is in the substantially horizontal position, facilitating a customized lens for a particular application and/or eliminating potential lens damage during storage and prior manufacturing steps. Portions of such manufacturing can take place or be implemented on an assembly line or conveyor belt. The support members can be made of mating pairs of support members. In exemplary embodiments, each member of a pair can include an integrally formed male or female connection.
Other aspects, embodiments, and details of the of present disclosure will be apparent from the following description when read together with the accompanying drawings.
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:
While certain embodiments are depicted in the drawings, one skilled in the art will appreciate that the embodiments depicted are illustrative and that variations of those shown, as well as other embodiments described herein, may be envisioned and practiced within the scope of the present disclosure.
Aspects and embodiments of the present disclosure provide luminaires and methods, in which alternative light sources (LEDs in exemplary embodiments) are utilized in place of, or replacing, fluorescent lights. While the preferred embodiment employs LED 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”. Such lighting according to the present disclosure can be used to retro-fit existing lighting assemblies and applications 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.
While generally applicable to the retrofitting of most fluorescent light applications, embodiments of the present disclosure may be particularly well-suited for application of retro-fitting of refrigerated food cases such as those commonly found in supermarkets and convenience stores. Such refrigerated cases, can include cases for chilled foods and/or drinks, as well as those used to display frozen foods.
As can be seen in
Light strip 120(1) includes a support member 122 having opposed ends that are held relative to snap brackets 128 by the bracket assemblies 130(1), 130(2), 132(1) and 132(2). In embodiments utilizing circuitry driven light sources such as LEDs, the support member 122 can have one or more printed circuit boards 124 of any size mounted on its surface. An inline configuration of three printed circuit boards 124 is shown in
The bracket assemblies can include a pair of cylindrical brackets 130(1), 130(2) and a pair of offset members or brackets 132(1), 132(2). Each cylindrical bracket can be configured to fit within a snap bracket 128, which can be of the configuration commonly used for holding a fluorescent light bulb. Suitable fasteners (e.g., screws, bolts, press-fit dowels, etc.) 134 and 138 may be used for the connections between the support member and/or the cylindrical brackets 130(1), 130(2).
In exemplary embodiments, PCB 124 can include FR4 as printed circuit board material. Other epoxy-glass laminates may also be used. Solder pads can be present on each end of each PCB 124 for wire attachment.
In an exemplary embodiment in which LEDs are employed as the light sources, an assembly of LEDs (e.g., preferably a strip of LEDs) can be utilized with one or more light boards having power and control circuitry for the LEDs; such boards can provide one or more substrates on or in which each LED and other components of the assembly can be created or deposited, such as LEDs themselves, and a related optical element (such as a lens or other refractive element, or a reflector) for directing at least a portion of the light emitted from the LED. An LED assembly can hold one or more LEDs, and one or more optics (or optical elements), to a board, and can define the positioning of the one or more optics with respect to the LEDs. The optics can be positioned over each of the LEDs, respectively; a single optical element, e.g., a single cylindrical lens or a poured plastic lens, etc., can be positioned for use with one or more LEDs. Suitable examples of LED and optic trays that hold the optics in position with respect to LEDs on a printed circuit board are described in U.S. Patent Publication No. 2006/146531 and in U.S. Provisional Patent Application No. 60/981,984; the entire contents of both of which applications are incorporated herein by reference.
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 includes 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 124 can include an onboard driver to run the light sources, e.g., LEDs, with a desired current. For example, a current suitable for an LED may be used. For example, a representative current range could include, but is not limited to about 250 mA to about 800 mA; one exemplary current is about 350 mA. A circuit board 124 can have a bus, e.g., a 24V DC bus, going from one end to the other. Other voltages may of course be used for a bus. Any suitable number of suitable LEDs 126 can be disposed on a light strip board. In one illustrative example, five (5) Rebel LEDs (LUXEON® Rebel LEDs as made commercially available by the Philips Lumileds Lighting Company)—operational at 80 Lumens minimum may be employed with the luminaire of the present disclosure. Other suitable LEDs or alternative light sources and output values may be used within the scope of the present disclosure.
Referring now to
As shown in
In exemplary embodiments (e.g., as shown for
In exemplary embodiments, support members 122A, 122B may be made by extrusion of 6063T5 aluminum alloy constructed according to known extrusion techniques. In exemplary embodiments, cylindrical bracket 130(1) can be made of 6063T5 aluminum alloy. Moreover, in an exemplary embodiment, the offset members 132 can be formed of suitable metal such as a sheet of aluminum alloy (e.g., with a thickness of 0.050 inches). Other suitable materials, e.g., plastics, may be used in addition to or substitution for the ones previously described for the support members, brackets and/or members.
Referring now to
Similar to the embodiment shown in
Also shown in
Bracket 530 may include a tab 538 configured to pass through a hole 536 in the mullion 520 as shown. A fastener (e.g., bolt) 532 may be used to connect bracket 530 to light strip support member 522. Set screw 534 may be used to secure the connection between mullion 520 and support member 522. Hole(s) 536 may be pre-existing holes, already having been formed for a pre-existing fluorescent lighting fixture.
In
When circuit board 624 is in a substantially horizontal position, a lens can be formed on each light source 626 (or one or more light sources). For example, a plastic lens may be formed by pouring a plastic-containing liquid with suitably colored or transparent plastic over each light source 626, and then allowing the plastic to cool or cure (or otherwise causing the plastic to harden). In such a way, a lens of desired shape can be formed over each light source. In certain embodiments, lens materials including the following may be used: Lord Corporation Urethane model 7550, or Momentive (formerly GE) silicone models: TSE397, TSE397 or RTV 615.
Where the configuration of the support members does not alone facilitate orienting the circuit board horizontally, the support members may be placed on one or more related bases or supports to facilitate horizontal orientation. In the depicted embodiment of
Referring to
Continuing with the description of
In exemplary embodiments, lens 806 is made of an extrusion of polycarbonate. 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, 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 can 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 retro-fit applications to pre-existing fluorescent lighting structures and fixtures.
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.