Patent Application
20140104836
This invention relates to light fixtures and, more particularly, to street and roadway light fixtures and the like, including light fixtures for illumination of large areas. More particularly, this invention relates to such light fixtures which utilize LEDs as light source.
Light fixtures such as floodlights are often used for illumination of a selected area or object and typically need to be adjusted into a desired orientation for maximal effect. Adjustable light fixtures are popular with architects, lighting designers and building owners as a way to visually “highlight” certain building and landscape features and improve the nighttime appearance of buildings and grounds. Large properties such as auto dealerships may require, e.g., a dozen or even several dozen well-placed floodlights for the intended illumination purpose. Architects and lighting designers are justifiably concerned that each floodlight be capable of being precisely directed toward the particular feature to be illuminated. This means that the floodlight should have a mounting arrangement that permits a wide range of aiming angles.
High-luminance light fixtures using LED modules as light source present particularly challenging problems. One particularly challenging problem for high-luminance LED light fixtures relates to heat dissipation. Among the advances in the field are the inventions disclosed in co-owned patent application Ser. No. 11/860,887, filed Sep. 25, 2007, now U.S. Pat. No. 7,686,469, issued Mar. 30, 2010, the entirety of the contents of this application is incorporated herein by reference.
Improvement in dissipating heat to the atmosphere is one significant objective in the field of LED light fixtures. It is of importance for various reasons, one of which relates to extending the useful life of the lighting products. Achieving improvements without expensive additional structure and apparatus is much desired. This is because a major consideration in the development of high-luminance LED light fixtures for various high-volume applications, such as roadway lighting, is controlling product cost even while delivering improved light-fixture performance.
In summary, finding ways to significantly improve the dissipation of heat to the atmosphere from LED light fixtures would be much desired, particularly in a fixture that is easy and inexpensive to manufacture.
The present invention relates to improved LED light fixtures. The LED light fixture may include a plurality of heat-sink-mounted LED-array modules, each module engaging an LED-adjacent surface of a heat-sink base for transfer of heat from the module. Heat-sink heat-dissipating surfaces may extend away from the modules. In certain embodiments, the inventive LED light fixture includes at least one venting aperture through the heat-sink base to provide air ingress to the heat-dissipating surfaces adjacent to the aperture.
In some of such embodiments, the LED light fixture includes a plurality of heat sinks, each heat sink with its own heat-dissipating surfaces and heat-sink base. Each heat-sink base may have one of the LED-array modules engaged thereon and being wider than the module thereon such that the heat-sink base includes a beyond-module portion.
The at least one venting aperture may include at least one venting aperture through the beyond-module portion of the heat-sink base. In some embodiments, the at least one venting aperture along the beyond-module portion of the heat-sink base includes at least two venting apertures along the beyond-module portion. The heat sinks may be made by extrusion.
In certain embodiments, the heat-sink heat-dissipating surfaces include the surfaces of at least one edge-adjacent fin extending transversely from the beyond-module portion of the heat-sink base at a position beyond the venting apertures therealong. The venting apertures along the beyond-module portion may be spaced along the heat sink, which may be made by extrusion. In such embodiments, the beyond-module portion of the heat-sink base has at least one non-apertured portion extending thereacross to allow heat flow across the beyond-module portion toward the at least one edge-adjacent fin extending therefrom.
In some embodiments, the venting apertures along the beyond-module portion include two elongate apertures extending along the extrusion in spaced substantially end-to-end relationship. The at least one non-apertured portion may include a non-apertured portion which is between the two elongate apertures and is located substantially centrally along the length of the heat sink, which may be made by extrusion. In some of such embodiments, the combined length of the apertures along the beyond-module portion constitutes a majority of the length of the extrusion.
In certain embodiments, the heat-sink base includes a second beyond-module portion, the two beyond-module portions of the heat-sink base being along opposite sides of the module. In some of such embodiments, the at least one venting aperture also includes at least one venting aperture through the second beyond-module portion, and in some the at least one venting aperture includes at least two venting apertures along each of the beyond-module portions.
In some of such embodiments the surfaces of the at least one edge-adjacent fin extending transversely from each of the beyond-module portions are at positions beyond the venting apertures therealong. The venting apertures along each of the beyond-module portions of the heat-sink base may be spaced along the extrusion. Each of the beyond-module portions of the heat-sink base has at least one non-apertured portion extending thereacross to allow heat flow across such beyond-module portion toward the at least one edge-adjacent fin extending therefrom.
In some embodiments, the venting apertures along each one of the beyond-module portions include two elongate apertures extending along the extrusion in spaced substantially end-to-end relationship. The at least one non-apertured portion of each one of the beyond-module portions of the heat-sink base includes a non-apertured portion which is between the two elongate apertures and is located substantially centrally along the length of the extrusion. In some of such embodiments, the combined length of the apertures along each of the beyond-module portions constitutes a majority of the length of the extrusion.
In the embodiments where the heat-sink base includes a second beyond-module portion, the heat-sink base includes a module-engaging portion between the beyond-module portions. In some of such embodiments, the heat-sink heat-dissipating surfaces include the surfaces of a plurality of middle fins extending transversely from the module-engaging portion of the heat-sink base.
The edge-adjacent fins extending from each one of the beyond-module portions of the heat-sink base may be a single edge-adjacent fin, such two edge-adjacent fins forming the opposite lateral sides of the heat sink, which may be an extrusion. In some of such embodiments, the heat-sink base has a thickness at positions adjacent to the edge-adjacent fins that is greater than the thickness of the base at positions adjacent to some of the middle fins, thereby to facilitate conduction of heat laterally away from the module.
In certain embodiments, each of the edge-adjacent fins has a base-adjacent proximal portion integrally joined to the heat-sink base and a distal edge remote therefrom, the proximal portions of the edge-adjacent fins being thicker than the proximal portions of at least some of the middle fins, thereby to facilitate conduction of heat away from the module. The heat-sink base may have a thickness at positions adjacent to the edge-adjacent fins that is greater than the thickness of the base at positions adjacent to some of the middle fins, thereby to facilitate conduction of heat laterally away from the module.
In some embodiments, all of the fins extend away from the heat-sink base in a first direction. In some of such embodiments, the edge-adjacent fins also extend from the heat-sink base in a second direction opposite to the first direction to provide additional heat-dissipating surface. In such embodiments, the edge-adjacent fins and the heat-sink base may form an H-shaped structure.
In certain embodiments, the plurality of heat sinks are beside one another in positions such that the beyond-module portion of each of the heat sinks is adjacent to but spaced from the beyond-module portion of another of the heat sinks. Such arrangement further facilitates flow of cool air to the heat-dissipating surfaces of the heat sinks and thermal isolation of the heat sinks from one another.
In some of such embodiments, the spacing between the heat sinks is at least as great as the widths of the venting apertures in the beyond-module portions of the heat-sink bases.
Some embodiments of the inventive light fixture includes a housing and an LED assembly which includes the heat-sink-mounted LED-array modules. In some of such embodiments, the LED assembly and the housing form a venting gap therebetween to provide air ingress along the heat-sink base to the heat-dissipating surfaces.
The LED-array modules may be substantially rectangular elongate modules. Examples of LED-array modules are disclosed in co-owned U.S. Pat. No. 7,938,558, the contents of which are incorporated herein by reference.
The LED assembly may include a plurality of heat sinks each with its own heat-dissipating surfaces and heat-sink base. In some of such embodiments, each heat-sink base has one of the LED-array modules engaged thereon, the base being wider than the module thereon such that the heat-sink base includes a beyond-module portion. In such embodiments, the at least one venting aperture includes at least one venting aperture through the beyond-module portion of the heat-sink base.
Another aspect of this invention is a mounting assembly which includes a bar having a gripping region and a gripper grips the gripping region such that the light fixture is held with respect to the static structure. The bar has a first end secured with respect to one of the static structure and a main body portion of the light fixture. The gripper is attachable to the other of the static structure and the main body portion of the light fixture.
In certain embodiments the mounting assembly it is not adjustable. The bar may have a cross-sectional shape which is gripped by the gripper such that the fixture is held in only one orientation. Such cross-sectional shape of the bar may include rectangular shapes such as square.
In some embodiments, the inventive mounting assembly facilitates adjustment of the light fixture to a selected one plurality of possible orientations during installation. In some of such embodiments, the gripper grips the gripping region such that the light fixture is held in a selected one of the plurality of possible orientations.
In some embodiments, the first end of the bar is secured with respect to the main body portion of the light fixture. In such embodiments, the gripper is attachable to the static structure.
In certain embodiments of the adjustable mounting assembly, the gripper and the bar may be configured for a finite number of the orientations. The mounting assembly of some of such embodiments further includes a guide indicating the angle for each of the orientations of the light fixture with respect to the static structure.
The guide may be a bracket removably secured with respect to the bar at a plurality of positions therealong. In some embodiments, the bracket is shaped to follow the outer shape of the bar and includes angle markings, and the gripper has a reference line which points to a particular one of the angle markings indicating the angle of the light fixture with respect to the static structure.
The bar also has a second end opposite the first end. In some embodiments, the second end may also be secured with respect to the main body portion; in such embodiments, the gripping region is between the first and second ends and is spaced from the main body portion. In some of such embodiments, the gripper-bar orientations include a number of positions of the gripper along the bar.
In some embodiments, the bar defines a plurality of positions for securing the bracket therealong.
The mounting assembly of the present invention may further include at least one bar support that projects from the main body portion. In such embodiments, the first end of the bar is supported by the bar support such that the gripping region is along and spaced from the main body portion. The bar support may include a bar-support portion engaged with the first end of the bar. In some embodiments, the bar is hollow. In such embodiments, the bar-support portion is inserted into the first end of the bar. The bar interior and the bar-support portion preferably shaped to prevent relative rotation.
In certain embodiments, the gripper includes first and second bar-engaging portions facing one another with the bar therebetween. The bar is preferably substantially cylindrical. In such embodiments, each of the bar-engaging portions has a semi-cylindrical bar-engaging surface. The semi-cylindrical bar-engaging portions together encircle and engaging the bar.
The gripper and the bar are configured for a finite number of orientations. The gripping region and the gripper preferably have anti-rotational interlocking features complementary to one another such that, when the anti-rotational interlocking features of the bar-engaging portions are interlocked with the interlocking features of the bar, the light fixture is held in a selected one of a finite plurality of orientations. The anti-rotational interlocking features may include parallel inter-engaged flutes and grooves along the gripping region of the bar and the gripper. The bar may be made by extrusion, e.g., of a suitable metal such as aluminum or tough, rigid, structural polymeric material.
The first bar-engaging portion may be configured for securement with respect to the static structure and the second bar-engagement portion be configured for attachment to the first bar-engagement portion with the bar sandwiched therebetween. In some versions, the first bar-engaging portion is configured for attachment atop a light pole.
Yet another aspect of the present invention is a light fixture including the main body portion and the mounting assembly for adjustable securement to a static structure such that, when the anti-rotational interlocking features of the bar-engaging portions are interlocked with the interlocking features of the bar, the light fixture is held in a selected one of a finite plurality of orientations.
As used herein in referring to portions of the devices of this invention, the terms “upward,” “upwardly,” “upper,” “downward,” “downwardly,” “lower,” “upper,” “top,” “bottom” and other like terms assume that the light fixture is in its usual position of use.
In descriptions of this invention, including in the claims below, the terms “comprising,” “including” and “having” (each in their various forms) and the term “with” are each to be understood as being open-ended, rather than limiting, terms.
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It is further seen in
Heat-sink heat-dissipating surfaces include the surfaces of edge-adjacent fins 621 extending transversely from beyond-module portion 681 of heat-sink base 68 at a position beyond venting apertures 69 therealong. As best seen in
Heat-sink base 68 includes a module-engaging portion 685 between beyond-module portions 681. Heat-sink heat-dissipating surfaces include the surfaces of a plurality of middle fins 622 extending transversely from module-engaging portion 685 of heat-sink base 68, as seen in
As also seen in
It is seen in
Fins 621 and 622 extend away from heat-sink base 68 in a first direction B. Edge-adjacent fins 621 also extend from heat-sink base 68 in a second direction A opposite to first direction B to provide additional heat-dissipating surface 624. Edge-adjacent fins 621 and heat-sink base 68 are shown to form an H-shaped structure seen in
It is seen in
As seen in
Light fixture 10 includes a housing 23 with LED assembly 60 secured with respect thereto such that LED assembly 60 and housing 23 form a venting gap 18A therebetween to provide air ingress along heat-sink base 68 to the heat-dissipating surfaces. As seen in
Examples of LED-array modules are disclosed in co-pending U.S. patent application Ser. No. 11/774,422, the contents of which are incorporated herein by reference. In fixtures utilizing a plurality of emitters, a plurality of LEDs or LED arrays may be disposed directly on a common submount in spaced relationship between the LEDs or LED arrays. These types of LED emitters are sometimes referred to as chip-on-board LEDs.
The above-described thermal management of the LED light fixture including venting gaps 18A, 18B and through heat sink venting apertures 69 allows to maximize power density of LEDs on the printed circuit board to 4.9 W per square inch. This is in contrast to prior fixtures limited to 3.2 W per square inch. In the inventive light fixture, the LED junction temperature and resulting lifetime of the LEDs is improved even at the higher power density which results in a 50,000 hour lumen maintenance factor of a minimum of 86% at 15° C.
Furthermore, the inventive thermal management of the LED light fixture allows each heat sink to function in thermal isolation from neighboring heat sinks which minimizes thermal compromise with increasing the number of heat sinks in the modular LED light fixture as fixture 10 shown in the drawings. In the fixture according to the present invention, a number lumens delivered per unit area of the modular LED assembly (sometimes referred to as “light engine”) is increased from previously possible 95 lumens per square inch to over 162 lumens per square inch. This is allowed by the inventive thermal management of the LED light fixture.
This is in contrast with prior modular fixtures in which due to the thermal interference between adjacent heat sinks, an increase the number of light engine heat sinks resulted in a decrease in lumen flux to as low as 56 lumens per square inch.
It is further seen in
Light fixture 10 includes a main body portion 20 and a mounting assembly 30 for adjustable securement to a static structure. An exemplary static structure is shown in
Mounting assembly 30 illustrated in
In
In
Bar-engaging surfaces 431 and 441 of gripper 40 and gripping region 32 of bar 31 are configured for a finite number of the orientations. As seen in
While the principles of the invention have been shown and described in connection with specific embodiments, it is to be understood that such embodiments are by way of example and are not limiting.
This application is based in part on U.S. Provisional Application Ser. No. 61/624,211, filed Apr. 13, 2012. This application is also a continuation-in-part of patent application Ser. No. 13/333,198, filed Dec. 21, 2011, now U.S. Pat. No. 8,313,222, issued Nov. 20, 2012, which in turn is a continuation of patent application Ser. No. 12/418,364, filed Apr. 3, 2009, now U.S. Pat. No. 8,092,049, issued Jan. 10, 2012, which in turn is based in part on U.S. Provisional Application Ser. No. 61/042,690, filed Apr. 4, 2008. The entirety of the contents of all such applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61624211 | Apr 2012 | US | |
| 61042690 | Apr 2008 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13333198 | Dec 2011 | US |
| Child | 13680481 | US | |
| Parent | 12418364 | Apr 2009 | US |
| Child | 13333198 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13680481 | Nov 2012 | US |
| Child | 13839922 | US |
