Patent Application
20160097523
The device and methods disclosed herein relate generally to lamps, and particularly to lamps designed to dissipate waste heat efficiently.
The lighting industry as a whole has undergone a huge transition, moving from halogen and incandescent light sources to more efficient light sources such as light emitting diodes (“LEDs”). In particular, there is increase interest in the employment of LEDs as light sources for theater lighting. This growth has been due in large part to the power efficiency and light output of the LEDs. Historically, the low light output from LEDs made them impractical for use in applications requiring significant light output, for example, in outdoor applications. However, as LED light output continues to increase from improvements in semiconductor and LED efficiency, LEDs are finding application in an increase number of areas.
These new light sources present different challenges to manufacturers than traditional lighting. In particular, LED lighting designs require special pains to avoid the buildup of heat in the LEDs. Unlike incandescent and halogen lights, which can operate at high temperatures, LED lighting requires effective thermal management to keep the LED within the optimal thermal envelope. Reduced efficiency, reduced lifespan, or damage to the LED units can result from extended high temperature operation. As a result, effective cooling is crucial. Typically, LED lighting designs use some form of heat exchanger transport heat away from LEDs to heat sinks, which use relatively greater mass to absorb the heat while dissipating it to air or other fluid through structures such as fins. A common drawback is that the heat sink core structures must be extruded or cast then bonded to the fins. Alternately, the entire heat sink core and fin structure can be machined from a single piece of metal. The machinery and expertise required such manufacturing is often expensive and complex, with significant investment required in tooling or CAM programming prior to production.
It common for LED lighting to be incorporated into a device designed specifically for the unique thermal profile of LED lighting. In the theater environment, this presents a number of problems. For example, a lighting unit that utilizes the lamp body as a cooling system may be unable to shed heat effectively without requiring changes to the size, mounting, or supporting components such that it is incompatible with existing lamps. Specially designed lamp bodies that incorporate LED lighting are expensive, and require replacement of the entire unit.
Therefore, there remains a need for heat dissipation designs in lighting that can be cheaply and effectively manufactured and incorporated into existing lighting structures.
Disclosed herein is a lamp with a laminar heat sink assembly. The lamp includes a plurality of thermally conducting plates. Each thermally conducting plate includes a bonding portion and a heat-dissipating structure. The bonding portions of the plurality of thermally conducting plates are fixed together to form a laminar block. The lamp includes a light source thermally connected to the laminar block.
In a related embodiment, each bonding portion of the bonding portions of the plurality of thermally conducting plates includes a first surface and a second surface, and wherein the first surface of at least one first bonding portion is fixed against the second surface of at least one second bonding portion. In another embodiment, the first surface of the at least one first bonding portion is fused to the second surface of the at least one second bonding portion. In an additional embodiment, the plurality of bonding portions are fixed together using a plurality of fasteners. In still another embodiment, the bonding portion of each of the plurality of thermally conducting plates is substantially flat. In yet another embodiment, the at least one heat dissipation structure of each heat conducting plate includes at least one wing. In some embodiments, each wing has at least one perforation. In an additional embodiment, the wing of each thermally conducting plate projects from the laminar block at a different angle from each wing of each adjacent thermally conducting plate. In another embodiment still, the wings are displaced radially around the laminar block.
In another related embodiment, the lamp further includes a fan positioned to blow air over the at least one heat-dissipating structure of at least one of the plurality of thermally conducting plates. In a further embodiment, the light source is thermally connected to the laminar block by a heat pipe that contacts the laminar block and on which the light source is deployed. In a further embodiment still, the light source deployed against the laminar block. In another embodiment, the lamp also includes a lamp reflector shaped to focus the light from the light source. In an additional embodiment, the light source is deployed within the lamp reflector. Another embodiment of the lamp includes a light guide, the light guide including a total internal reflection conduit having a proximal end receiving substantially all light from the light source and a distal end projecting into the lamp reflector and a diffuse reflector, positioned at the distal end of the conduit, and shaped to reflect light back onto the lamp reflector. In a related embodiment, the diffuse reflector is embedded in the distal end of the conduit, and the diffuse reflector is further shaped to reflect light at an angle less than the critical angle of the conduit surface, so that the light passes through the conduit and strikes the lamp reflector. In another related embodiment the light source further includes a reflective backing shaped to direct substantially all light emitted by the light source into the proximal end of the conduit. Still another embodiment also includes a light fixture in which the light source and plurality of thermally conducting plates are incorporated.
Also disclosed is a method for manufacturing a laminar heat sink. The method includes producing a plurality of thermally conducting plates, each thermally conducting plate comprising a bonding portion and a heat-dissipating structure. The method includes fixing together the bonding portions of the plurality of thermally conducting plates to form a laminar block. An additional embodiment of the method also includes thermally connecting a light source to the laminar block.
Other aspects, embodiments and features of the disclosed device and method will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying figures. The accompanying figures are for schematic purposes and are not intended to be drawn to scale. In the figures, each identical or substantially similar component that is illustrated in various figures is represented by a single numeral or notation at its initial drawing depiction. For purposes of clarity, not every component is labeled in every figure. Nor is every component of each embodiment of the device and method is shown where illustration is not necessary to allow those of ordinary skill in the art to understand the device and method.
The preceding summary, as well as the following detailed description of the disclosed device and method, will be better understood when read in conjunction with the attached drawings. It should be understood that the invention is not limited to the precise arrangements and instrumentalities shown.
Embodiments of the disclosed lamp incorporate a laminar heat sink that is easy and inexpensive to manufacture. The heat sink can be readily modified to suit the needs of various different lighting solutions with minor changes to the manufacturing process. This flexibility and ease of manufacture allows the heat sink to be incorporated in special-purpose lighting, such as theater lighting, at a minimal cost.
Each of the thermally conducting plates 101 may be constructed from any combination of thermally conducting materials. Each thermally conducting plate 101 may be constructed of a single thermally conducting material. Each thermally conducting plate 101 may be constructed of a combination of thermally conducting materials. Each thermally conducting plate 101 may be constructed of a combination of thermally conducting materials with materials that are not thermally conducting. Each thermally conducting plate 101 may be constructed of electrically conductive materials. In some embodiments, each thermally conducting plate 101 is composed at least partly of metal. The metal may be aluminum. The metal may be steel. In some embodiments, each thermally conducting plate 101 is composed of a thermally conductive polymer material. In some embodiments, each thermally conducting plate 101 is composed of a thermally conductive ceramic. Each thermally conducting plate 101 may be composed of electrically insulating materials; for instance, Each thermally conducting plate 101 may be composed of a thermally conductive but electrically insulating ceramic. Each thermally conducting plate 101 may be composed of a thermally conductive but electrically insulating plastic or other polymer. Each thermally conducting plate 101 may be composed of a combination of electrically conducting and electrically insulating materials.
Each thermally conducting plate 101 includes a bonding portion 102. The bonding portion 102 of each plate 101 is formed so that it may be combined with the bonding portions of the other thermally conducting plates 101, of the plurality of thermally conducting plates 101, to form a laminar block 104. The laminar block 104 is composed of the bonding portions 102 of the plates 101, tightly joined to form a solid block having similar properties to a single monolithic block of thermally conducting material. As an example, as illustrated in
In some embodiments, the bonding portions 102 are shaped so that they fit together closely to form the laminar block. The bonding portion 102 of each of the plurality of thermally conducting plates 101 may be substantially flat. In some embodiments, the bonding portions 102 are not flat, but are formed so that the first surfaces 106b have profiles that fit the profiles of the corresponding second surfaces 107a; for instance, a first surface 106b may have a protruding portion such as a ridge that fits into a corresponding depression, such as a groove, in the corresponding second surface 107a. In some embodiments, the bonding portions are formed uniformly in a way that creates reciprocal shapes, for instance by stamping identical blanks as described in further detail below. Because each thermally conducting plate 101 interfaces with at least one other thermally conducting plate 101 via the laminar block 104 to form the heat sink, thermal load may be transferred from the light source, or a conductor from the light source as described below, directly to a heat plate or the thermal load may be conducted through adjacent heat plates and dissipation of the thermal load may be effected by the heat sink as a unitary structure.
In some embodiments, at least one of the thermally conducting plates 101 has at least one heat-dissipating structure 103. In other embodiments, each of the thermally conducting plates 101 has at least one heat-dissipating structure 103. The at least one heat dissipating structure 103 may be a structure that enhances the dissipation of heat into the surrounding air by radiation and convection. The at least one heat-dissipating structure 103 may be constructed of any materials suitable for the construction of a thermally conducting plate 101; the at least one heat-dissipating structure 103 and the remainder of the thermally conducting plate 101 may be formed together as a single monolithic unit. The at least one heat-dissipating structure may function by increasing the surface area of the laminar heat sink that is exposed to the air; thus, the at least one heat-dissipating structure may be any structure that increases that surface area. The at least one heat-dissipating structure may be a fin. The at least one heat-dissipating structure may be at least one wing. By way of illustration,
Referring again to
As shown in
The light source 105 is thermally connected to the laminar block 104. In one embodiment, the light source 105 is thermally connected to the laminar block 104 if there is a thermally conductive path from the light source to the laminar block 104. In some embodiments, the light source is thermally connected to the laminar block by a heat pipe 110 that contacts the laminar block and on which the light source is deployed. In one embodiment, a heat pipe 110 is an enclosed conduit that transports heat from a first heat-conducting end against a heat source to a second heat-conducting end against a heat sink, using a phase changing material; the phase-changing material absorbs heat from the first end, vaporizing in the process, travels as vapor to the second end, condenses at the second end while transferring heat to the second end, and then travels back to the first end as liquid. In some embodiments, the liquid travels by gravity. In other embodiments, the liquid travels by capillary action, through porous laser-sintered metal powder, grooves, or screens. In some embodiments, the phase-changing material is a material that is above its melting point, and below its critical temperature at either end of the heat pipe; the phase-changing material may be selected to have boiling point that allows the heat pipe to transfer the heat with maximal efficiency at the operating temperature of the light source 105. The heat pipe 110 may contact the block 104 in a manner that permits efficient heat conduction from the condensing end of the heat pipe 110 to the block 104. The contact surfaces of the block 104 and/or heat pipe 110 may be machined for optimal contact between the heat pipe 110 and the contact surface of the block 104. The contact surfaces may also be treated with coatings or compounds to improve thermal transfer, including but not limited to thermal pads, thermal paste, or thermal grease.
The light source 105 may be thermally connected to the laminar block 104 by being deployed against the laminar block 104. In some embodiments, the light source 105 is configured for contact with the block 104 such that the surface of the light source 105 is in direct or proximate contact with the laminar block 104, which allows for optimal transfer of heat from the light source 104 to the laminar block 104. As in other embodiments, the contact surfaces of the laminar block 104 may be machined for optimal contact with the thermal load, in this case being the light source 105. The contact surfaces may also be treated with coatings or compounds to improve thermal transfer, including but not limited to thermal pads, thermal paste, or thermal grease. The light source 105 may also be deployed on a projecting portion of the laminar block 104; the light source 105 may be deployed on a conducting projection deployed on the laminar block 104.
In some embodiments, as depicted in
In other embodiments, as shown in
The diffuse reflector 114 may be embedded in the distal end 113b of the conduit, and wherein the diffuse reflector is further shaped to reflect light at an angle less than the critical angle of the conduit surface, so that the light passes through the conduit and strikes the lamp reflector. The diffuse reflector 114 may be conical, with its apex pointing toward the proximal end 113a of the conduit 113; light reflecting down the conduit 113 will thus reflect off the reflector 114 at an angle steeper than the critical angle, passing through the walls of the conduit 113 and shining onto the lamp reflector 111. As a result, the light guide 112 may act as a diffuse reflector to match original dispersal characteristics of a tungsten filament. In a typical tungsten filament lamp, the original light has two focal points at the reflector and at the gate. Whereas common lamps can only collect about 65% of light emitted from a tungsten filament, the lamp 100 with the light guide 112 may retain more collection onto the reflector because there is no light loss in directions not striking the reflector. In some embodiments, this provides a more consistent radiation pattern because multi-filament obstruction doesn't occur as it would in a traditional four element tungsten lamp. The diffuse reflector 114 that is embedded in the distal end 113b of the conduit 113 may contribute to improvement of the diffusion pattern by avoiding an air gap. The light guide may employ a silicon diffuse reflector.
In some embodiments, as shown in
In some embodiments, the laminar heat sink has the benefits of simplified manufacture when compared with extruded heat sinks, cast heat sinks, and billet heat sinks The laminar heat sink may be constructed more cheaply, in less time, and with less waste than competing designs. Cast heat sinks require creation of a mold and related tooling, which must be produced before production can begin and are often replaced periodically during manufacture. Extruded heat sinks similarly require customized tooling and equipment capable of operating the extrusion process at elevated temperature and/or pressures. Billet heat sinks are costly, often require costly 3-dimensional machining, and are considerably slower to produce than the disclosed laminar heat sink.
In further detail, and as further illustrated by 1A-2F, the method 300 involves producing a plurality of thermally conducting plates 101, each thermally conducting plate 101including a bonding portion and a heat-dissipating structure (301). In some embodiments, each plate 101 is produced by molding. In some embodiments, each plate 101 is cut from a sheet of material; the plate 101 may be cut from a sheet of material using lasers, high-powered water jets, saws, or machine tools, such as cutting tools. In some embodiments, each plate 101 is cut from a blank of material; the blanks may be identical. The plates 101 may be molded to form blanks, and then cut to add details, such as perforations 108, into the plates 101. In other embodiments, perforations 108 are produced in the molding process. The heat dissipation structures 103 may be formed separately and attached to the bonding portions 103; in other embodiments, the heat dissipation structures 103 and bonding portions 102 are formed together as a monolithic whole. For instance, the heat dissipation structures 103 and bonding portions 102 may be formed in a single mold. The heat dissipation structures 103 may be cut out of the same sheet or blank as the bonding portions 102 at the same time. In some embodiments, the molding process produces heat dissipation structures 103 that are angled; the heat producing structures 103 may be variously angled, as disclosed above in reference to
The method 300 includes fixing together the bonding portions of the plurality of thermally conducting plates to form a laminar block 104 (302). For instance, first surface 106b of at least one first bonding portion 102b may be fixed against the second surface 107a of at least one second bonding portion 102a. The first surface 106b of the at least one first bonding portion 102b may be fused to the second surface 107a of the at least one second bonding portion 102a. The fusion may be accomplished by any suitable procedure; for instance first surface 106b may be adhered to the second surface 107a. The first surface 106b may be welded to the second surface 107a. The first surface 106b may be brazed to the second surface 107a. In other embodiments, the plurality of bonding portions 102 are fixed together using fasteners. The fasteners may be one or more rivets. The fasteners may be one or more screws. The fasteners may be one or more bolts. The fasteners may be one or more captive fasteners. The fasteners may be one or more clamps. The fasteners may be one or more ties.
Some embodiments of the method 300 further involve thermally connecting a light source 105 to the laminar block 104. The light source 105 may be thermally connected to the laminar block 104 by any means described above in reference to
It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.
