The present invention relates generally to lighting fixtures and luminaires, and more particularly, relates to a lighting fixture having enhanced heat sink performance with a heat sink member connecting upper and lower portions of an outdoor lighting globe.
Today many companies are offering decorative outdoor light emitting diode (LED) retrofit kits and new LED fixtures in order to take advantage of the long life, excellent color and beam control and other benefits of LEDs. LEDs are temperature sensitive and generate a significant amount of heat, which must be removed from the fixture in order to assure long life and adequate illumination.
To date, manufacturers have placed LEDs on heat sinks, which are either inside the optical and/or housing area or are mounted to an opaque metal top to provide heat extraction from the fixture. The problem with these designs is that much of the heat remains trapped inside the optical cavity and limits the wattage of the LED light engine and therefore the total lumen package is less than is required for many applications. To date, no solution has been developed to provide for a luminous globe, wherein the top and bottom both emit light and have an external heat sink adequate to dissipate significant wattage.
High power LEDs are also very bright and it is both unappealing in a decorative application and, due to glare, poor for visibility that the individual LEDs should be visible as points of light.
Conventional arrangements of globes with LEDs mounted to heat sinks inside the optical cavity do a poor job of hiding the LED due to the proximity of the LED to the surface of the globe. Such conventional arrangements trap the heat from the light engine inside the globe and do not mimic traditional light sources for which the globes were designed.
Conventional arrangements of globes with heat sinks mounted in the top have opaque tops and do not mimic the desired appearance of luminous globes. Further, the fixture tops are usually inferior heat sinks or compromise beam spread in order to accommodate the aesthetic design.
Other conventional arrangements of globes with heat sinks in the base have limited surface area, inferior heat dissipation and generally require more optical elements, decreasing efficiency.
A need exists for a new lighting fixture that employs a heat sink and light distribution, which preserves and enhances the aesthetic design of the luminous globe while optimizing heat extraction and providing a configuration for maximizing optical performance.
A principal aspect of the present invention is to provide a lighting fixture having an enhanced heat sink performance. Other important aspects of the present invention are to provide such lighting fixture substantially without negative effect and that overcome many of the disadvantages of prior art arrangements.
In brief, a lighting fixture having an enhanced heat sink performance is provided. A heat sink member is a unitary ring member. An outside surface of the heat sink member is disposed exterior of the lighting fixture and includes a plurality of outwardly extending fins. An inside surface of the heat sink member is disposed inside of the lighting fixture and includes a plurality of surfaces configured for mating engagement with a light source boards. The heat sink member joins upper and lower globe portions of the lighting fixture.
In accordance with features of the invention, the lighting fixture includes an outdoor lighting globe. The heat sink member is formed of a thermally conductive material, such as aluminum. The unitary ring member and the outwardly extending vertical fins have a selected size and configuration for providing enhanced heat sink performance.
In accordance with features of the invention, the outwardly extending fins are outwardly extending vertical fins integrally formed with the unitary ring member. Each of the light source boards includes a predefined number of light emitting diodes (LEDs). The light source board includes a metal core circuit board.
In accordance with features of the invention, a light pipe is used to redirect the LED light output. The light pipe includes a selected one of a fibre optic light pipe, and an acrylic light pipe.
In accordance with features of the invention, a reflector is provided inside the lighting fixture below the heat sink member to redirect the LED light output. The reflector includes a predefined contour to provide directional illumination control.
In accordance with features of the invention, another reflector is provided inside the lighting fixture above the heat sink member to redirect the LED light output. The reflector includes a predefined contour and a plurality of slots to provide an upper controlled illumination component and also to provide a lower directional illumination control.
In accordance with features of the invention, mating surface portions are configured for mating engagement with a respective light source boards that are canted at an angle to direct a LED light output proximate to a point on a light center of the fixture.
In accordance with features of the invention, a polygon shaped lighting fixture provides a LED light output to cross in a plane proximate to a light center of the fixture.
In accordance with features of the invention, a plurality of mounting clips are provided with the heat sink member to connect the upper and lower globe portions of the lighting fixture.
The present invention together with the above and other objects and advantages may best be understood from the following detailed description of the preferred embodiments of the invention illustrated in the drawings, wherein:
In accordance with features of the invention, a lighting fixture having an enhanced heat sink performance is provided. A unitary heat sink member includes a plurality of outwardly extending fins having a selected size and configuration for providing enhanced heat sink performance.
Having reference now to the drawings, in
The heat sink member 102 includes a unitary band or ring member, which joins the upper globe portion 104 and lower globe portion 106. An exterior surface 110 of the heat sink ring member 102 is disposed exterior of the lighting fixture 100 and is exposed to the air for optimal cooling. The exterior surface 110 of the heat sink member 102 includes a plurality of integrally formed, outwardly extending vertical exterior fins 112 for enhanced thermal transfer performance. As illustrated in
The heat sink member 102 is formed of a selected thermally conductive material, such as cast aluminum and is either painted or anodized to protect the heat sink member from corrosion. The heat sink member 102 also can be formed of copper or other metal. The outwardly extending vertical exterior fins 112 of the heat sink member 102 have a selected size and arrangement, for example, 2.25″ tall and 0.65″ wide, spaced, 0.49 ″apart, and has a combined total of 330 square inches of surface area.
The upper globe portion 104 and lower globe portion 106 are formed of a substantially transparent light transmitting material, such as an acrylic or similar material. The upper globe portion 104 and lower globe portion 106 are implemented, for example, with an A.L.P. LexaLite Model 424 top and a LexaLite Model 424, manufactured and sold by A.L.P. Lighting & Ceiling Products, Inc. of Niles, Ill.
Referring now to
The ring shaped heat sink interior surface 114 has a plurality of mating surfaces 116, for example, twelve (12) mating interior surfaces 116. Referring also to
The LED boards 900 including the metal core circuit board, such as 4 Cree XPG LEDs, are driven at 750 ma each with a total of 48 LEDs and 96 watts, not including the power supply. The fixture efficacy or lumens per watt for the lighting fixture 100 with these LEDs is greater than 60 lumens per watt. The optical efficiency of the lighting fixture 100 is greater than 70%.
The ring shaped heat sink member 102 is suited for dissipating at least 100 watts of heat, in an ambient temperature of 25 degrees C. and resulting in a maximum junction temperature of 75 degrees C. on the above referenced boards.
In
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The heat sink member 202 includes a unitary band or ring member, which joins the upper reflector portion 204 and lower globe portion 206. An exterior surface 210 of the heat sink ring member 202 is disposed exterior of the lighting fixture 200 and is exposed to the air for optimal cooling. The exterior surface 210 of the heat sink member 202 includes a plurality of integrally formed, outwardly extending vertical exterior fins 212 for enhanced thermal transfer performance.
An inside surface 214 of the heat sink member 202 has predetermined surfaces 216 which allow selective positioning of the LEDs (not shown in
The heat sink member 202 is formed of a selected thermally conductive material, such as cast aluminum and is either painted or anodized to protect the heat sink member from corrosion. The heat sink member 202 also can be formed of copper or other metal. The upper reflector portion 204 is formed, for example, of spun or hydroformed aluminum. The lower globe portion 206 is formed of a substantially transparent light transmitting material, such as an acrylic or similar material, for example, including prismatic elements (not shown in
Referring now to
The heat sink member 302 includes a unitary band or ring member, which joins the upper reflector portion 304 and lower globe portion 306. An exterior surface 310 of the heat sink ring member 302 is disposed exterior of the lighting fixture 300 and is exposed to the air for optimal cooling. The exterior surface 310 of the heat sink member 302 includes a plurality of integrally formed, outwardly extending vertical exterior fins 312 for enhanced thermal transfer performance.
An inside surface 314 of the heat sink member 302 has predetermined surfaces 316 which allow selective positioning of the LEDs (not shown in
The heat sink member 302 is formed of a selected thermally conductive material, such as cast aluminum and is either painted or anodized to protect the heat sink member from corrosion. The heat sink member 302 also can be formed of copper or other metal. The upper reflector portion 304 is formed, for example, of cast aluminum or stamped steel. The lower globe portion 306 is formed of a substantially transparent light transmitting material, such as an acrylic or similar material, for example, including prismatic elements 318 formed on the outside surface. The upper reflector portion 304 and lower globe portion 306 are implemented, for example, with an A.L.P. LexaLite Model 210 top and a LexaLite Model 210, manufactured and sold by A.L.P. Lighting & Ceiling Products, Inc. of Niles, Ill.
Referring now to
An inside surface 414 of the heat sink member 402 has predetermined surfaces 416 which allow selective positioning of the LEDs (not shown in
The heat sink member 402 is formed of a selected thermally conductive material, such as cast aluminum and is either painted or anodized to protect the heat sink member from corrosion. The heat sink member 402 also can be formed of copper or other metal, such as stamped steel. The lower globe portion 406 is formed of a substantially transparent light transmitting material, such as an acrylic or similar material, for example, including prismatic elements 418 formed on the outside surface.
Referring now to
An exterior surface 506 of the heat sink member 502 includes a plurality of integrally formed, outwardly extending vertical exterior fins 508 for enhanced thermal transfer performance. The heat sink member 502 includes an inside surface 510 having predetermined angle which allow selective positioning of the LEDs 512 to provide optimal lumen performance. All the LEDs 512 have beam centers aimed to cross in a plane generally designated by the reference character 514 that is on a designed light center generally designated by the reference character 516.
The heat sink member 502 is formed of a selected thermally conductive material, such as cast aluminum and is either painted or anodized to protect the heat sink member from corrosion. The heat sink member 502 also can be formed of copper or other metal, such as stamped steel. The lower lantern body portion 504 is formed of a substantially transparent light transmitting material, such as a clear glass, white or frosted glass or similar material.
While the present invention has been described with reference to the details of the embodiments of the invention shown in the drawing, these details are not intended to limit the scope of the invention as claimed in the appended claims.