Patent Application
20110051418
This invention relates generally to wall-mounted light fixtures and more particularly to wall-mounted light fixtures that use light-emitting diodes.
Wall-mounted light fixtures of various kinds are known in the art. Such fixtures typically mount to a vertical wall (such as a building wall or a privacy, security, or cantilevered wall) and extend outwardly of the wall. One simple, ubiquitous example in these regards is the standard front-porch light found on many homes in the United States. Such fixtures often serve a variety of light purposes. This can include, for example, providing lighting for security purposes, aesthetic purposes, convenience and safety purposes, and so forth. Sometimes, a given light fixture serves more than one such purpose.
Traditionally, such wall-mounted light fixtures often employ incandescent light bulbs to serve as a primary source of illumination. Such light sources, however, are quite inefficient. Concerns in these regards have created interest in employing more efficient light sources in various application settings. For example, light-emitting diodes (LED's) are capable of providing light more efficiently than a typical incandescent light bulb.
Though more efficient, however, LED's do generate heat. This heat, in turn, can negatively impact the operation, output, and operating life of the LED when improperly managed. Physically managing excess heat generated by one or more LED's in a wall-mounted light fixture application setting, in turn, faces numerous challenges. Besides serious cost considerations, aesthetics play a significant part in limiting design options for wall-mounted light fixtures. Not only must the end result be visually pleasing in and of itself, the design must also look like a more-or-less typical wall-mounted light fixture. While significant aberrations in these regards may find some few fans, for the most part, the market demands a traditional appearance that admits of only small, rather than significant, changes to the form and function of the wall-mounted light fixture.
This, then, presents a conundrum for the designer; somehow providing a wall-mounted light fixture that can safely and effectively use LED's as a primary source of illumination while also achieving a solution that can readily accommodate use in the traditional form factor of standard wall-mounted light fixtures without unduly negatively impacting corresponding traditional aesthetics and functionality.
The above needs are at least partially met through provision of the method and apparatus pertaining to heat sinking a light-fixture light-emitting diode described in the following detailed description, particularly when studied in conjunction with the drawings, wherein:
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.
Generally speaking, these various embodiments pertain to a wall-mounted light fixture configured to be mounted on a vertical wall. This wall-mounted light fixture comprises an LED-mounting surface having one or more LED's mounted thereon to serve as a primary source of illumination for the wall-mounted light fixture. This wall-mounted light fixture also generally comprises a housing that contains the one or more LED's. This housing also comprises, on a side that is directly thermally coupled to the LED(s) and that is oriented towards and disposed closest to the aforementioned vertical wall (when the wall-mounted light fixture is properly mounted on the vertical wall), a heat sink. This heat sink is thermally coupled to the LED-mounting surface and has an exterior portion shaped to have a large surface area to thereby substantially increase a heat-exchange capacity of the heat sink. So configured, this heat sink dissipates heat exuded by the LED(s) and thereby greatly aids in maintaining the efficient and reliable operation of the LED(s).
By one approach, this heat sink can comprise an integrally-formed component shaped, for example, with an L-shaped side profile. By another approach, this heat sink can comprise a physically separate component from the LED-mounting surface. So configured, the heat sink can be mechanically and thermally joined to the LED-mounting surface to provide the desired thermal pathway between the heat-generating LED(s) and the heat-dissipating heat sink.
As noted, the heat sink itself has a portion that is shaped to offer a large surface area to thereby increase the heat sink's heat-exchange capacity. By one approach this can comprise providing the heat sink with a plurality of fins. By another approach, alone or in combination with the foregoing, this can comprise providing the heat sink with a plurality of pins.
So configured, a rearward-facing panel of a typical four-panel wall-mounted light fixture can serve, in whole or in part, as the aforementioned heat sink. This, in turn, significantly preserves the traditional aesthetics of the resultant fixture. The remaining panels can comprise transparent panels in accord with traditional practice in these regards. That the rear panel is partially or wholly opaque (due to the presence of the heat sink) will largely pass without notice as a viewer will typically not stand between the fixture and the wall and hence will not be availed of a viewing angle that will readily reveal this condition. Further, the opaque nature of the rear panel as discerned from the front or the side is not particularly surprising due to the relative proximity of the wall and hence does not call undue attention to itself.
The presence of the heat sink, in turn, can greatly assist in effectively managing the heat exuded by the LED(s). This can lead to greater consistency of lighting levels during usage (even for extended periods of time). This can also lead to increased operating lifetimes for the LED(s). Those skilled in the art will also appreciate that the considerable heat-handling capabilities of such a heat sink permit a considerable number of powerful LED's to be employed in a given wall-mounted light fixture. This, in turn, permits the fixture to provide a considerable amount of resultant lighting suitable for any number of lighting purposes.
These and other benefits may become clearer upon making a thorough review and study of the following detailed description. Referring now to the drawings, and in particular to
This process 100 provides the step 101 of providing a heat sink having a portion that is shaped to have a large heat-exchanging surface area. By one approach, and referring momentarily to
In this example, the portion shaped to have a large heat-exchanging surface area comprises a plurality of heat-exchanging fins 205. These fins are substantially identical to one another and are disposed perpendicular to the heat-exchange leg 202 and substantially parallel to one another. This configuration provides an unobstructed air channel between adjacent fins 205. By one approach these fins 205 are configured such that, when the heat sink 200 is mounted in a wall-mounted light fixture, these fins 205 will be oriented at least substantially parallel to the vertical axis of the housing. The general design and operation of such a heat sink comprises a well-understood area of endeavor and requires no further elaboration here.
Also in this example the LED-mounting surface 203 has a hole 206 disposed there through to receive electrical wiring (not shown). This electrical wiring serves to deliver electricity to effect energization of the corresponding LED (not shown). By one approach, the LED would be mounted underneath the illustrated LED-mounting surface 203. In such a case the aforementioned electrical wiring would then extend upwardly (in this view) in order to connect to an electrical power source. Of course the power source may be conditioned from a generally available source (such as a mains supply) into a source more suitable to power the LED as is well known in the art.
In the described example the heat sink 200 comprises an integral structure. That is, the heat-exchange leg 202 and the LED-mounting surface 203 are physically one with one another and are not separable from one another absent the use of a destructive process such as cutting or breaking.
These teachings will readily accommodate other approaches in these regards, however. For example, and referring now momentarily to
As noted above, the heat sink 200 has a portion shaped to have a large heat-exchanging surface area. As used herein, this reference to a “large heat-exchanging surface area” will be understood to refer to a form factor that is specifically designed and intended to provide a greatly increased surface area over what would otherwise be afforded by the form factor envelope itself. This can be accomplished, for example, by the use of indentations, undulations, and other surface irregularities.
As noted above, by one approach this large heat-exchanging surface area can comprise a plurality of fins. With momentary reference now to
As noted, the heat sink 200 serves to absorb heat from an LED(s) mounted to the LED-mounting surface 203 and to dissipate that heat via the large heat-exchanging surface area. Those skilled in the art understand that some materials serve better in these regards than others. By one approach, for example, a portion or all of the heat sink 200 can comprise aluminum or a suitable aluminum alloy.
Referring now to
In this particular illustrative example, the LED-mounting surface 203 is disposed upwardly in the light-fixture housing 501. So configured, the heat-exchange leg of the heat sink 200 forms the panel of the wall-mounted light fixture 500 that is oriented towards and disposed closest to the vertical wall 501 when the wall-mounted light fixture 500 is properly mounted on the vertical wall 501. As used herein, the expression “properly mounted” will be understood to refer to an installation of the wall-mounted light fixture 500 that accords with the intended design and configuration of the wall-mounted light fixture 500 (“intended,” that is, by the manufacturer and distributor of the fixture). For example, it would not comprise a proper mounting in this case to mount the light fixture 500 with its longitudinal axis perpendicular to the vertical wall 501; though perhaps physically possible, such a mounting scheme would run contrary to the intended design and configuration of this particular fixture.
So configured, that exterior portion of the heat sink having the large surface area to thereby substantially increase the heat-exchange capacity of the heat sink (i.e., in this illustrative example, the heat-exchange fins 205) is disposed towards the vertical wall 501. As shown in
With continued reference to
It will be understood that this LED 505 as is thermally coupled to this heat sink 200 serves as the primary source of illumination for this wall-mounted light fixture 500. That is, regardless of whether the primary purpose of the light fixture is to provide general ambient lighting, security lighting, safety lighting, or otherwise, this LED 505 provides the major component of the intensity of that lighting (that is, more than 50% of that lighting). When using more than one such LED 505 in this manner, the resultant plurality of LED's 505 collectively serve as the primary source of the fixture's illumination.
That said, those skilled in the art will appreciate that such LED's can be mounted in any number of positions with respect to the aforementioned large heat-exchanging surface area. As one illustration in these regards, and referring now to
As another illustrative example in these regards, and referring now to
As noted above, these teachings will readily accommodate using two or more LED's. As one further illustrative example in such regards, and referring now to
When using a plurality of LED's, these teachings will readily accommodate using different LED's. The LED's may differ from one another, for example, with respect to their output lumens, their output directionality, their power requirements, the color of their light output, their size, their form factor, their mounting requirements, and so forth.
So configured, the rear panel of a wall-mounted light fixture comprises, in whole or in part, at least that portion of a heat sink as comprises a large heat-exchanging surface area. So disposed, this large heat-exchanging surface area is oriented towards the vertical wall upon which the light fixture is mounted and is therefore, for the most part, out of sight to the ordinary observer. Given the proximity of the light fixture to the wall, it is unlikely that an observer in ordinary course will attempt to view the light from the backside of the light fixture. From essentially all other points of view, the light exuded by the LED(s) will be transmitted through the partially or fully transparent panels of the light fixture such that the wall-mounted light fixture looks and functions, for all effective purposes, as an ordinary traditional wall-mounted light fixture in such regards.
Those skilled in the art will therefore appreciate and understand that these teachings permit one or more LED's to serve as the primary source of illumination for a wall-mounted light fixture without unduly compromising the traditional aesthetics associated with wall-mounted light fixtures or the quantity and nature of light that is otherwise functionally expected from such a fixture. These beneficial results are achieved in a cost-effective manner. It will further be appreciated that these results can be applied in conjunction with numerous existing designs for wall-mounted light fixtures and that these teachings hence serve to greatly leverage the existing capabilities and functionality of such platforms. It will also be appreciated that these teachings are highly scalable and can be employed with a variety of differently-sized light fixtures, form factors, and lighting output requirements.
Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the spirit and scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept. For example, these teachings can be readily applied with a wall-mounted light fixture having more, or fewer, panels than four. As another example in these regards, the inside surface of the panel that comprises the heat sink can be partially or fully mirrored. Reflections from that mirrored surface, in turn, can assist in disguising the fact that this panel is, in fact, largely or fully opaque.
