Patent Application
20100110699
The present invention relates in general to light fixtures and, more specifically, to a recessed light fixture having a removable trim with thermally effective properties.
Light emitting diodes (LEDs) have been used for decades in applications requiring relatively low-energy indicator lamps, numerical readouts, and the like. In recent years, however, the brightness and power of individual LEDs has increased substantially, resulting in the availability of 1 watt and 5 watt devices.
While small, LEDs exhibit a high efficacy and life expectancy as compared to traditional lighting products. A typical incandescent bulb has an efficacy of 10 to 12 lumens per watt, and lasts for about 1,000 to 2,000 hours; a general fluorescent bulb has an efficacy of 40 to 80 lumens per watt, and lasts for 10,000 to 20,000 hours; a typical halogen bulb has an efficacy of 20 lumens and lasts for 2,000 to 3,000 hours. In contrast, red-orange LEDs can emit 55 lumens per watt with a life-expectancy of about 100,000 hours.
Because LED devices generate heat, the use of LEDs or LED lamps in a recessed can fixture or housing can present problems due to the thermal constraints of LEDs—heat negatively affects the optical and electrical performance of LEDs. Because conventional recessed can applications tend to be thermally inefficient and do not provide adequate heat ventilation, an LED device installed into a recessed can housing will quickly generate substantial amounts of heat within the housing that can damage the device.
Presently, most of the recessed can housings for residential and commercial applications are fully sealed at the can top, which means there is no air passage from the can to the space above the housing. Also, in most cases, the thermal insulation in the attic is placed around the can further restricting the flow of heat out of the housing. As a result, there is no effective heat dissipation path from the can housing to the attic.
An LED-based lamp installed into a recessed can housing requires an effective heat dissipation path to operate and to maintain its optical and electrical performance, longevity and reliability.
The recessed can is one of the most widely used light fixtures in modern homes in the United States. There are millions of incandescent light bulbs installed into recessed can fixtures. Successful retrofit of an LED lamp to the existing and new recessed can housings may result in an 80% decrease in lighting energy consumption and an increase of the lamp's operating life from a typical 2,000 hours incandescence to the 50,000 hours of an LED device.
In one embodiment, the present invention is a lighting assembly comprising a light fixture having a light source and heatsink thermally coupled to the light source. A removable trim is mountable to the light fixture. The removable trim has a flange with thermally conductive properties around a perimeter of the trim. The light fixture and removable trim are mounted to a housing.
In another embodiment, the present invention is a lighting assembly comprising a light fixture having a light source and heatsink thermally coupled to the light source. A removable trim is mountable to the light fixture. The removable trim has a flange, recessed portion, and rim. The flange has thermally conductive properties.
In another embodiment, the present invention is a removable trim mountable to a light fixture comprising a flange having thermally conductive properties, rim, and recessed portion disposed between the flange and rim.
In another embodiment, the present invention is a method of making a lighting assembly comprising the steps of providing a light fixture having a light source, mounting a heatsink to the light fixture in thermal communication with the light source, and forming a removable trim mountable to the light fixture. The removable trim has a flange, recessed portion, and rim. The flange has thermally conductive properties.
a illustrates a perspective view of a recessed can light fixture including a thermally conductive trim and heatsink for redistributing heat;
b illustrates a cross-sectional view of a recessed can light fixture including a thermally conductive trim and heatsink for redistributing heat;
a-4b illustrate perspective views of the thermally conductive trim section of the light fixture of
a-6b illustrate perspective views of the thermally conductive trim of
a-7b illustrate perspective views of the thermally conductive trim of
a-9b are perspective views of a thermally conductive trim having an integrated heatsink and being configured to couple to a light source;
a-10d illustrate perspective views of mechanisms for coupling a light fixture to an interior portion of a recessed can housing;
a-11c show the LED-based light source with removable thermally conductive trim;
a-12b show another LED-based light source with removable trim having thermally conductive properties;
a-14b show another LED-based light source with removable trim for mounting to a ceiling;
a-15c show the LED-based light source with removable trim mounted in the ceiling.
a-16b show another LED-based light source with a junction box; and
a-17b show the LED-based light source with junction box mounted in the ceiling.
The present invention is described in one or more embodiments in the following description with reference to the Figures, in which like numerals represent the same or similar elements. While the invention is described in terms of the best mode for achieving the invention's objectives, it will be appreciated by those skilled in the art that it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims and their equivalents as supported by the following disclosure and drawings.
a and 2b illustrate recessed can fixture 10 housing a light source.
Excessive heat minimizes the lifespan of both conventional light bulbs and LED light sources. In some cases, excessive heat also modifies the operating properties of a light source. For example, because the light generation properties of many LED light sources are at least partially governed by temperature, a significant change in the ambient temperature surrounding an LED light source may cause a change in the output color of light emitted from the device. Accordingly, a thermally efficient fixture minimizes both the risk of fire and the effect of temperature on the output color and lifespan of the light source contained within the fixture.
Fixture 10 is configured to install into both conventional 12.7 cm (5 inch) and 15.24 cm (6 inch) recessed can housings. However, fixture 10 may be configured to be installed into a recessed can housing having other geometries. Depending upon the installation, different attachment mechanisms may be used to secure fixture 10 within the housing. As new recessed housings are developed with different geometries, new attachment mechanisms with different lengths or other attributes can be manufactured for coupling to and installing fixture 10 into those housings.
Fixture 10 includes several components that are coupled together to provide efficient dissipation of heat energy from within the device. Fixture 10 includes trim 12. Trim 12 includes a flange that, after installation of fixture 10, protrudes from the recessed can housing. Heatsink 14 is coupled to trim 12 to facilitate the removal of heat energy from trim 12 and fixture 10. Light source 15 (shown on
Turning to
During operation, the light source generates heat. In a conventional recessed can fixture, the heat would ordinarily be generated by the light bulb and travel upwards within the housing. After leaving the light bulb, the heat is trapped in the recessed housing. As the device generates additional heat, the temperature within the housing increases and negatively affects the performance of the light fixture. In some cases, the excess heat shortens the operative lifetime of the device or degrades the optical qualities of the light source. In other cases, the excess heat may result in a fire risk. Typical incandescent recessed can fixtures require thermal cutoff devices to be connected in series with the incandescent lamp to prevent a fire risk when overheating.
In the present embodiment, however, as the light source operates, heat is transferred directly into trim 12 from the light source. As the temperature of trim 12 increases, heat is vented from the flange portion of trim 12 that resides outside the recessed can housing. Also, because trim 12 is connected to heatsink 14, a portion of the heat residing in trim 12 is transmitted into heatsink 14 where it is then vented within the recessed housing. Although some heat is vented into the recessed housing via heatsink 14, a majority of heat is dissipated from trim 12 outside the housing. Accordingly, fixture 10 minimizes heat build-up within the recessed housing.
In this configuration, heat energy flows from the light source, into trim 12, where a portion of the heat energy is dissipated from trim 12. Heat energy remaining in trim 12 is transferred into heatsink 14. As such, heatsink 14 may be regarded as acting as a heatsink for trim 12 rather than the light source directly.
Trim 12 and the flange of trim 12 generally dissipates more heat energy from the light source than heatsink 14. By doing so, trim 12 minimizes heat build-up within the recessed can housing. The following analysis describes an example installation of fixture 10 and illustrates a process for determining the ratio of energy dispersed from trim 12 versus heatsink 14. In the example, trim 12 includes a thermally conductive material such as aluminum, and has an outer diameter of 200 mm, an inner diameter of 130 mm and a depth of 42 mm (see
Convection heat transfer (Qconv) for trim 12 is shown by equation (1):
Qconv=ηh Atrim dT (1)
where η: trim efficiency,
In equation (1), η=tanh mL/mL where mL=(h/(k*t*L))1/2*L3/2. Accordingly, mL=(10/(180×0.002×0.064))1/2×0.0643/2 or 0.33. As such, η=tanh 0.33/0.33=0.965.
Radiation heat transfer for trim 12 is shown by equation (2):
Q
rad
=εσA
trim
F(Ttrim4−Tamb4) (2)
where ε: emissive ˜0.90,
The same equations can be established for heatsink 14. In the example, heatsink 14 includes a thermally conductive material and has a plurality of fins having an effective surface area of approximately Aheatsink=0.065 m2.
Convection heat transfer (Qconv) for heatsink 14 is shown by equation (3):
Qconv=ηh Aheatsink dT (3)
where η: heatsink efficiency=η(heatsink base)×η(heatsink fins),
In equation (3), η=tanh mL/mL where mL=(2*h/(k*t*L))1/2*L3/2. Accordingly, mL=(2×5(20*23*2+52*π)/52*π)/(180×0.005×0.060))1/20.0603/2 or 0.52. Accordingly, η=tanh 0.52/0.52=0.91.
Radiation heat transfer for heatsink 14 is shown by equation (4):
Q
rad
=εσA
heatsink
F(Theatsink4Tamb4) (4)
where ε: emissive ˜0.30,
Having determined the convection and radiation heat transfer equations for trim 12 and heatsink 14, it is possible to determine the energy balance of the system. The system includes trim 12, heatsink 14, and the LED light source that generates heat energy. The energy balance is given by equation (5):
Q
led
=Q
trim
+Q
heatsink (5)
Assuming worst case conditions, the energy generated by an LED light source (Qled) is approximately 15 watts. The ambient temperature of heatsink 14 (Theatsink) deposited within a fully-insulated recessed can housing is approximately 50° C. The ambient temperature of trim 12 (Ttrim) residing outside the recessed can housing is approximately 35° C. The ambient temperature of the room (Tamb) is approximately 25° C. Given these conditions, it is possible to determine the energy stored in trim 12 and heatsink 14. The energy within trim 12 (Qtrim) is determined by equation (6):
Q
trim
=Q
conv
Q
radi (6)
With reference to equation (6), Qtrim=ηhAtrimdT+εσAtrimF (Ttrim4−Tamb4). Qtrim=0.965×5×0.0296×(Ttrim−35)+0.95×5.669×10−8×0.0296×0.9×(Ttrim4−3084). Accordingly, Qtrim=(0.143 Ttrim−4.99)+(1.43×10−9×Ttrim4−12.86).
The energy within heatsink 14 (Qheatsink) is determined by equation (7):
Q
heatsink
=Q
conv
Q
radi (7)
With reference to equation (7), Qheatsink=ηhAheatsink dT+εσAheatsinkF (Theatsink4−Tamb4). Qheatsink=0.91×0.065×5×(Theatsink−50)+0.3×5.669×10−8×0.065×0.5×(Theatsink4−3234). Accordingly, Qheatsink=0.295Theatsink−14.78+5.527×10−10Theatsink4−6.01.
Assuming the temperature of heatsink 14 is equal to the temperature of trim 12 (T=Ttrim=Theatsink), equations (6) and (7) can be combined to generate equation (8):
15=0.438T+1.983×10−9T4−38.64 (8)
Numerical analysis of equation (8) results in a value of T=˜61° C.
With the energy balance for the system, it is possible to determine the amount of heat transfer from trim 12 and heatsink 14 into the ambient air surrounding fixture 10. The energy dissipated by trim 12 at approximately 64.1° C. is given by equation (9):
Q
trim
=Q
conv
+Q
radi (9)
With reference to equation (9), Qtrim=ηh Atrim dT+εσAtrimF (Ttrim4−Tamb4). Qtrim=(0.143 Ttrim−4.99)+(1.43×10−9×Ttrim4−12.86). Accordingly, Qtrim=9.78 Watts. As such, trim 12 dissipates approximately 65% of the heat energy generated by the LED light source.
The energy dissipated by heatsink 14 at approximately 64.1° C. is given by equation (10):
Q
trim
=Q
conv
+Q
radi (10)
With reference to equation (10), Qheatsink=ηh Aheatsink dT+εσAheatsinkF (Theatsink4−Tamb4). Qheatsink=(0.295Theatsink−14.78)+(5.527×10−10Theatsink4−6.01). Accordingly, in this example, Qheatsink=5.22 Watts. As such, heatsink 14 dissipates approximately 35% of the heat energy generated by the LED light source. Accordingly, trim 12 dissipates more of the heat energy generated by the LED light source than is dissipated by heatsink 14.
As shown in the example, fixture 10 efficiently dissipates a majority of heat generated by the light source through trim 12 and outside of the recessed can housing. By doing so, fixture 10 minimizes heat build-up within the recessed can housing and mitigates the deleterious effects of heat on the light source of fixture 10.
Trim 12 includes a thermally conductive material such as aluminum, aluminum alloys, copper, thermally conductive plastics, or thermally conductive carbon fiber composite material. Trim 12 is formed using a one-piece stamping manufacturing process, however other processes such as die casting, deep draw stamping, and those that combine multiple pieces to form trim 12 may be used. Trim 12 includes an outer flange portion and a light source attachment point. The outer flange protrudes from fixture 10 and, after installation of fixture 10, may contact a ceiling or wall surface. Depending upon the application, the flange portion of trim 12 may include features such as grooves and beveled edges that increase the surface area of trim 12 and allow it to dissipate heat energy more efficiently. Trim 12 may also be painted with a thermally conductive material, or include other surface decorations.
Trim 12 includes a light source attachment point located inwardly from the flange. The attachment point provides a mount point for physically mounting the light source to trim 12. The attachment point may include features such as openings or recesses to facilitate the formation of an electrical connection between socket 16 and the light source. For example, the attachment point includes one or more holes through which electrical wiring passes, see
a and 4b illustrate an embodiment of trim 12. In
Turning to
Referring back to
Heatsink 14 includes a thermally conductive material such as those used to fabricate trim 12 and is formed using an extrusion, die casting or stamping process. Heatsink 14 includes a plurality of fin structures to facilitate dissipation of heat energy collected within heatsink 14 into the surrounding air. Heatsink 14 is mechanically connected to trim 12 to provide for transfer of heat energy from trim 12 to heatsink 14. In one embodiment, heatsink 14 is connected to trim 12 with a plurality of fasteners such as screws or bolts. A thermally conductive material such as thermal grease, a thermally conductive pad, or a thermal epoxy is deposited between heatsink 14 and trim 12 to enhance the thermal connection between the two structures. The thermal grease may include a ceramic, carbon or metal-based thermal grease.
Light source 15 is connected to trim 12 and acts as a light source for fixture 10. To facilitate transmission of thermal energy from light source 15 to the attachment area of trim 12, a layer of thermally conductive material is deposited between light source 15 and trim 12. The thermally conductive material may include thermal grease, epoxy, a thermal interface pad, or a phase change thermally conductive material. In various embodiments, the light source may include conventional incandescent light bulbs, LEDs, light engines or other light sources. In one embodiment, the light source is a light engine that includes a plurality of LEDs. The plurality of LEDs is electrically interconnected and a single electrical input into the light engine is used to power each of the LEDs. Any class of LED device may be used in the light engine, including individual die, chip-scale packages, conventional packages, and surface mounted devices (SMD). The LED devices are manufactured using semiconductor materials, including, for example, GaAsP, GaP, AlGaAs, AlGaInP, GaInN, or the like. In one installation, the light engine includes a single printed circuit board (PCB) having a plurality of connected LEDs. The LEDs are electrically interconnected using PCB traces or wirebonds so that when a supply voltage is applied to the light engine, each of the LEDs is activated and outputs light.
In the light engine, each of the individual LEDs have a particular color output corresponding to particular wavelengths. The various output colors of each of the LEDs combine together to form an output color for the entire light engine device. Accordingly, by selecting multiple LEDs of various colors to be combined into the light engine, the overall output color of the engine can be controlled. In one embodiment, the selected combination of LED devices includes x red LEDs, y green LEDs, and z blue LEDs, wherein the ratio x:y:z is selected to achieve a particular white light correlated color temperature (CCT) having a temperature of approximately 2700K, 3000K, or 3500K. In a further alternative embodiment, the light engine includes a plurality of red, green, blue and amber LEDs.
In general, any number of LED colors may be used in any desirable ratio. A typical incandescent light bulb produces light with a CCT of 2700K (warm white light), and a fluorescent bulb produces light with a CCT of about 5000K. Thus, more red and yellow LEDs will typically be necessary to achieve 2700K light, while more blue LEDs will be necessary for 5000K light. To achieve a high color rendering index (CRI), a light source must emit white light with a spectrum covering nearly the entire range of visible light (380 nm to 770 nm wavelengths), such that dark red, light red, amber, light green, dark green, light blue and deep blue should be placed in the mix. In one embodiment, for example, the mixing ratio (with respect to number of LEDs) of R (620 nm):Y (590 nm):G (525 nm):B (465 nm) is 6:2:5:1 to achieve 3200K light. A R:Y:G:B mixing ratio of 7:3:7:2 may be used to achieve 3900K light. In yet another embodiment, a ratio of 10:3:10:4 is used to achieve 5000K light. In addition to white light, fixture 10 may incorporate light engines that generate non-white colors of light using similar color blending techniques. In some embodiments, the light engine includes two or more colors of LEDs that are combined to form a composite output color.
In addition to the use of RAGE or RGB LEDs to emit white light, other combinations of LEDs may be used. For example, the light engine may include blue LEDs coated with phosphor or uV LEDs coated with phosphor.
a and 9b illustrate a thermally effective trim structure that includes a heatsink device. Trim 40 includes flange 42. Heatsink 44 is mounted to flange 42. Flange 42 and heatsink 44 may be formed as a single piece of material via an extrusion molding process, or may include separate pieces that are connected by a bonding process or by mechanical coupling. In one embodiment, flange 42 is connected to heatsink 44 using a plurality of fasteners. A thermally conductive material is deposited between flange 42 and heatsink 44. Trim 40 includes opening 46 that is configured to receive light source 48. Light source 48 includes an LED lamp, however other light sources such as conventional light bulbs may be used. Light source 48 is inserted into opening 46 (see
a-10d illustrate a plurality of attachment mechanisms for connecting fixture 10 to a recessed can housing.
In one embodiment, the present invention is a method of manufacturing a lighting assembly comprising providing a light fixture by (a) forming a trim by a stamping or die casting process. The trim has thermally conductive properties and includes a flange around a perimeter of the trim. Providing the light fixture includes (b) mounting a light source to a central portion of a front surface of the trim, and (c) forming a heatsink by an extrusion, die casting, or stamping process. The heatsink has thermally conductive properties. Providing the light fixture includes (d) mounting the heatsink to a back surface of the trim opposite the light source, and (e) connecting an attachment mechanism, such as a torsion spring, to the light fixture. The method includes providing a recessed can housing mounted to a ceiling tile surface and mounting the light fixture to the recessed can housing by (f) inserting the heatsink into the recessed can housing, and (g) engaging the attachment mechanism to an interior portion of the recessed can housing to brace the flange against the ceiling tile surface.
In another embodiment, the present invention is a method of manufacturing a light fixture comprising forming a trim by a stamping process. The trim has thermally conductive properties and includes a flange around a perimeter of the trim. The method includes mounting a light source to a central portion of a front surface of the trim, and forming a heatsink by an extrusion process. The heatsink has thermally conductive properties. The method includes mounting the heatsink to a back surface of the trim opposite the light source, and connecting an attachment mechanism to the light fixture.
In another embodiment, the present invention is a method of manufacturing a light fixture comprising forming a trim including a flange around a perimeter of the trim, mounting a light source to a front surface of the trim, mounting a heatsink to a back surface of the trim, and connecting an attachment mechanism to the light fixture.
In another embodiment, the present invention is a light fixture comprising a trim formed by a stamping process. The trim has thermally conductive properties and includes a flange around a perimeter of the trim. The light fixture includes a light source mounted to a central portion of a front surface of the trim, and a heatsink mounted to a back surface of the trim opposite the light source. The heatsink is formed by an extrusion process and has thermally conductive properties. The light fixture includes an attachment mechanism connected to the light fixture.
a illustrates another embodiment with light fixture 80 and separate, removable thermally conductive trim 82. Light fixture 80 is a thermally efficient structure that enables a heat-generating light source such as an LED lamp to safely operate in a typical top sealed recessed can housing. Excessive heat minimizes the lifespan of both conventional light bulbs and LED light sources. In some cases, excessive heat also modifies the operating properties of a light source. For example, because the light generation properties of many LED light sources are at least partially governed by temperature, a significant change in the ambient temperature surrounding an LED light source may cause a change in the output color of light emitted from the device. Accordingly, a thermally efficient fixture minimizes the effect of temperature on the output color and lifespan of the light source and AC/DC power converter contained within the fixture.
Fixture 80 includes components that are coupled together to provide efficient generation of light and dissipation of heat energy from within the device. Heatsink 84, similar to heat sink 14, is thermally coupled to the light source to remove heat energy from fixture 80. Fixture 80 includes a light source, similar to light source 15 in
The removable, thermally conductive trim 82 includes a flange 92, recessed portion 94, and rim portion 96 for mating to mounting rim 90 of light fixture 80. The recessed portion 94 reduces light glare. In one embodiment, recessed portion 94 is about 2 centimeters deep. Removable trim 82 is made with metal, thermally conductive plastic, or thermally conductive carbon fiber composite material using a stamping, molding, injection molding, or die casting process. Screws 98 are inserted into slots 100 and then twisted and tightened to secure trim 82 to fixture 80, as shown in
a illustrates another embodiment with light fixture 110 and separate, removable thermally conductive trim 112. Light fixture 110 is a thermally efficient structure that enables a heat-generating light source such as an LED lamp to safely operate in a typical top sealed recessed can housing. Excessive heat minimizes the lifespan of both conventional light bulbs and LED light sources. In some cases, excessive heat also modifies the operating properties of a light source. For example, because the light generation properties of many LED light sources are at least partially governed by temperature, a significant change in the ambient temperature surrounding an LED light source may cause a change in the output color of light emitted from the device. Accordingly, a thermally efficient fixture minimizes the effect of temperature on the output color and lifespan of the light source and AC/DC power converter contained within the fixture.
Fixture 110 includes components that are coupled together to provide efficient generation of light and dissipation of heat energy from within the device. Heatsink 114, similar to heat sink 14, is thermally coupled to the light source to remove heat energy from fixture 110. Fixture 110 includes a light source, similar to light source 15 in
The removable, thermally conductive trim 112 includes a flange 124, recessed portion 126, and rim portion 128 for mating to mounting rim 122 of light fixture 110. The recessed portion 126 reduces light glare. In one embodiment, recessed portion 126 is about 5 centimeters deep. Removable trim 112 is made with metal, thermally conductive plastic, or thermally conductive carbon fiber composite material using a stamping, molding, injection molding, or die casting process. Screws 130 are inserted into slots 132 and then twisted and tightened to secure trim 112 to fixture 110, as shown in
Fixtures 80 and 110 are each configured to install into conventional 4 inch (10.2 cm), 5 inch (12.7 cm), 6 inch (15.2 cm), and 8 inch (20.4 cm) recessed can housings. Fixtures 80 and 110 can also be configured to be installed into a recessed can housing having other geometries. Depending upon the installation, different attachment mechanisms may be used to secure the fixture within the housing. As new recessed housings are developed with different geometries, new attachment mechanisms with different lengths or other attributes can be manufactured for coupling to and installing fixtures 80 and 110 into those housings.
Turning to
In the present embodiment, as the light source operates, heat is transferred directly into removable trim 80 or 112 from the light source. As the temperature of trim 112 increases, heat is vented from the flange portion 124 of trim 112 that resides outside the recessed can housing. Also, because trim 112 is connected to heatsink 114, a portion of the heat residing in trim 112 is transmitted into heatsink 114 where it is then vented within the recessed housing. Although some heat is vented into the recessed housing via heatsink 114, a majority of heat is dissipated from trim 112 outside the housing. Removable trim 112 with flange 124 generally dissipates more heat energy from the light source than heatsink 114, as described in equations (1)-(10). Accordingly, fixture 110 minimizes heat build-up within the recessed housing.
Removable trim 112 includes a thermally conductive material such as aluminum, aluminum alloys, copper, thermally conductive plastics, or thermally conductive carbon fiber composite material. Trim 112 is formed using a one-piece stamping manufacturing process, however other processes such as die casting, deep draw stamping, and those that combine multiple pieces to form trim 112 may be used, see
a illustrates another embodiment with light fixture 150 and separate, removable thermally conductive trim 152. Light fixture 150 is a thermally efficient structure that enables a heat-generating light source such as an LED lamp to safely operate in without a recessed can housing but may have a thermal insulation layer above the ceiling panel. In some cases, excessive heat also modifies the operating properties of a light source. For example, because the light generation properties of many LED light sources are at least partially governed by temperature, a significant change in the ambient temperature surrounding an LED light source may cause a change in the output color of light emitted from the device. Accordingly, a thermally efficient fixture minimizes the effect of temperature on the output color and lifespan of the light source and AC/DC power converter contained within the fixture.
Fixture 150 includes components that are coupled together to provide efficient generation of light and dissipation of heat energy from within the device. Heatsink 154, similar to heat sink 14, is thermally coupled to the light source to remove heat energy from fixture 150. Fixture 150 includes a light source, similar to light source 15 in
The removable, thermally conductive trim 152 includes a flange 164, recessed portion 166, and rim portion 168 for mating to mounting rim 162 of light fixture 150. The recessed portion 166 reduces light glare. Removable trim 152 is made with metal, thermally conductive plastic, or thermally conductive carbon fiber composite material using a stamping, molding, injecting molding, or die casting process. Screws 170 are inserted into slots 172 and then twisted and tightened to secure trim 152 to fixture 150, as shown in
In
In the present embodiment, as the light source operates, heat is transferred directly into removable trim 152 from the light source. As the temperature of trim 152 increases, heat is vented from flange portion 164 of trim 152. Also, because trim 152 is connected to heatsink 154, a portion of the heat residing in trim 152 is transmitted into heatsink 154 where it is then vented. Although some heat is vented via heatsink 154, a majority of heat is dissipated from trim 152. Removable trim 152 with flange 164 generally dissipates more heat energy from the light source than heatsink 154, as described in equations (1)-(10). Accordingly, fixture 150 minimizes heat build-up within the recessed housing.
Removable trim 152 includes a thermally conductive material such as aluminum, aluminum alloys, copper, thermally conductive plastics, or thermally conductive carbon fiber composite material. Trim 152 is formed using a one-piece stamping manufacturing process, however other processes such as die casting, deep draw stamping, and those that combine multiple pieces to form trim 152 may be used, see
a illustrates another embodiment with light fixture 150 and separate, removable thermally conductive trim 152. In this case, electrical junction box 180 is mounted to fixture 150 and attached to flexible conduit 156. Junction box 180 has removable cover plate 182 with internal wiring 184, as shown in
In
While one or more embodiments of the present invention have been illustrated in detail, the skilled artisan will appreciate that modifications and adaptations to those embodiments may be made without departing from the scope of the present invention as set forth in the following claims.
The present application is a continuation-in-part of U.S. application Ser. No. 12/123,960, filed May 20, 2008, and claims priority to the foregoing application pursuant to 35 U.S.C. §120.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12123960 | May 2008 | US |
| Child | 12684580 | US |
