Patent Application
20130058099
The present invention relates to lighting. More specifically, the present invention relates to user-configurable high efficiency lighting sources.
The era of the Edison vacuum light bulb will be coming to an end soon. In many countries and in many states, common incandescent bulbs are becoming illegal, and more efficient lighting sources are being mandated. Some of the alternative light sources currently include fluorescent tubes, halogen, and light emitting diodes (LEDs). Despite the availability and improved efficiencies of these other options, many people have still been reluctant to switch to these alternative light sources.
The inventors of the present believe that there are several key reasons why consumers have been slow to adopt the newer technologies. One such reason is the use of toxic substances in the lighting sources. As an example, fluorescent lighting sources typically rely upon mercury in a vapor form to produce light. Because the mercury vapor is considered a hazardous material, spent lamps cannot simply be disposed of at the curbside but must be transported to designated hazardous waste disposal sites. Additionally, some fluorescent tube manufacturers go so far as to instruct the consumer to avoid using the bulb in more sensitive areas of the house such as bedrooms, kitchens, and the like.
The inventors of the present invention also believe that another reason for the slow adoption of alternative lighting sources is the low performance compared to the incandescent light bulb. As an example, fluorescent lighting sources often rely upon a separate starter or ballast mechanism to initiate the illumination. Because of this, fluorescent lights sometimes do not turn on “instantaneously” as consumers expect and demand. Further, fluorescent lights typically do not immediately provide light at full brightness, but typically ramp up to full brightness within an amount of time (e.g. 30 seconds). Further, most fluorescent lights are fragile, are not capable of dimming, have ballast transformers that can emit annoying audible noise, and can fail in a shortened period of time if cycled on and off frequently. Because of this, fluorescent lights do not have the performance consumers require.
Another type of alternative lighting source more recently introduced relies on the use of light emitting diodes (LEDs). LEDs have advantages over fluorescent lights including the robustness and reliability inherent in solid state devices, the lack of toxic chemicals that can be released during accidental breakage or disposal, instant-on capabilities, dimmability, and the lack of audible noise. The inventors of the present invention believe, however, that current LED lighting sources themselves have significant drawbacks that cause consumers to be reluctant to using them.
A key drawback with current LED lighting sources is that the light output (e.g. lumens) is relatively low. Although current LED lighting sources draw a significantly lower amount of power than their incandescent equivalents (e.g. 5-10 watts v. 50 watts), they are believe to be far too dim to be used as primary lighting sources. As an example, a typical 5 watt LED lamp in the MR16 form factor may provide 200-300 lumens, whereas a typical 50 watt incandescent bulb in the same form factor may provide 700-1000 lumens. As a result, current LEDs are often used only for exterior accent lighting, closets, basements, sheds or other small spaces.
Another drawback with current LED lighting sources includes that the upfront cost of the LED is often shockingly high to consumers. For example, for floodlights, a current 30 watt equivalent LED bulb may retail for over $60, whereas a typical incandescent floodlight may retail for $12. Although the consumer may rationally “make up the difference” over the lifetime of the LED by the LED consuming less power, the inventors believe the significantly higher prices greatly suppress consumer demand. Because of this, current LED lighting sources do not have the price or performance that consumers expect and demand.
Additional drawbacks with current LED lighting sources includes they have many parts and are labor intensive to produce. As merely an example, one manufacturer of an MR16 LED lighting source utilizes over 14 components (excluding electronic chips), and another manufacturer of an MR 16 LED lighting source utilizes over 60 components. The inventors of the present invention believe that these manufacturing and testing processes are more complicated and more time consuming, compared to manufacturing and testing of a LED device with fewer parts and a more modular manufacturing process.
Additional drawbacks with current LED lighting sources, are that the output performance is limited by heat sink volume. More specifically, the inventors believe for replacement LED light sources, such as MR16 light sources, current heat sinks are incapable of dissipating very much heat generated by the LEDs under natural convection. In many applications, the LED lamps are placed into an enclosure such as a recessed ceiling that already have an ambient air temperatures to over 50 degrees C. At such temperatures the emissivity of surfaces play only a small roll of dissipating the heat. Further, because conventional electronic assembly techniques and LED reliability factors limit PCB board temperatures to about 85 degrees C., the power output of the LEDs is also greatly constrained. At higher temperatures, the inventors have discovered that radiation plays much more important role thus high emissivity for a heat sink is desirable.
Traditionally, light output from LED lighting sources have been increased by simply increasing the number of LEDs, which has lead to increased device costs, and increased device size. Additionally, such lights have had limited beam angles and limited outputs.
The inventor of the present invention has also recognized that costs for selling lighting sources also include the costs of inventory. More specifically, as different models of lighting sources are designed, e.g. wide spotlight, medium spotlight, tight spotlight) the manufacturer, distributor, and/or reseller have to make, sell and stock these different models. Because of this, a large amount of capital tends to be tied up in inventory and carrying costs, and not spent on innovation.
Accordingly, what is desired is a highly efficient lighting source without the drawbacks described above.
The present invention relates to high efficient lighting sources. More specifically, the present invention relates to a novel LED lighting source and methods of manufacturing thereof. Some general goals include, to increase light output without increasing device cost or device size, to enable coverage of many beam angles, and to provide a high reliability product for long life (ROI).
Embodiments of the present invention utilize primary and secondary optics to determine the properties of the output light. Often, the primary optics includes a reflective optic and the secondary optic includes a transmissive optic (e.g. a lens). In some embodiments, the ultimate output beam angle, beam shape, beam transitions (e.g. falloff), and the like determined by the secondary optic.
In various embodiments of the present invention a user receives one or more partially-completed illumination sources from a manufacturer, distributor, or the like. The user selects one or more optical lenses for the partially-completed illumination sources such that the completed illumination sources achieve user desired light beam characteristics (e.g. angles, drop-off). Subsequently, the user couples the one or more optical lenses into the partially-completed illumination sources. The completed illumination sources, when powered, thus output light having the user-desired light beam characteristics. This enables the possibility of reducing the number of stock keeping units (SKUs) that have to be manufactured or inventoried. Accordingly, a single SKU can ship with a variety of secondary optics allowing the customer to determine which optic is to be installed in the field to match the desired application requirements.
According to one aspect of the invention, an illumination source configured to output light having a user-modifiable beam characteristic is disclosed. One device includes a LED light unit configured to provide a light output in response to an output driving voltage, and a driving module coupled to the LED light unit, wherein the driving module is configured to receive an input driving voltage and configured to provide the output driving voltage. One unit includes a heat sink coupled to the LED light unit, wherein the heat sink is configured to dissipate heat produced by the LED light unit and the driving module, and a reflector coupled to the heat sink, wherein the reflector is configured to receive the light output, and wherein the reflector is configure to output a light beam having a first beam characteristic. A source may include a lens coupled to the heat sink, wherein the lens is configured to receive the light beam having the first beam characteristic and wherein the lens is configured to output a light beam having a second beam characteristic. In some embodiments, the lens is selected by the user to achieve the second beam angle. In some embodiments, the lens is physically coupled to the heat sink by the user.
According to one aspect of the invention, a method for configuring a light source to provide a light beam having a user-selected beam characteristic is disclosed. One technique includes receiving a light source, wherein the light source includes: a LED light unit configured to provide a light output in response to an output driving voltage, a driving module coupled to the LED light unit, wherein the driving module is configured to receive an input driving voltage and is configured to provide the output driving voltage, a heat sink coupled to the LED light unit, wherein the heat sink is configured to dissipate heat produced by the LED light unit and the driving module, and a reflector coupled to the heat sink, wherein the reflector is configured to receive the light output, and wherein the reflector is configured to output a light beam having a first beam characteristic. A process includes receiving a user selection of a lens to achieve a second beam characteristic, wherein the lens is configured to receive the light beam having the first beam characteristic and wherein the lens is configured to output a light beam having the second beam characteristic. A method includes coupling the lens to the heat sink of the light source.
In order to more fully understand the present invention, reference is made to the accompanying drawings. Understanding that these drawings are not to be considered limitations in the scope of the invention, the presently described embodiments and the presently understood best mode of the invention are described with additional detail through use of the accompanying drawings in which:
In various embodiments, an LED assembly described in the pending patent applications described above, and variations thereof, may be used within LED lighting source 100. These LED assemblies are currently under development by the assignee of the present patent application. In various embodiments, LED lighting source 100 may provide a peak output brightness of approximately 7600 to 8600 candelas (with approximately 360 to 400 lumens), a peak output brightness of approximately 1050 to 1400 candelas for a 40 degree flood light (with approximately 510 to 650 lumens), and a peak output of approximately 2300 to 2500 candelas for a 25 degree flood light (with approximately 620 to 670 lumens), and the like. Various embodiments of the present invention therefore are believed to have achieved the same brightness as conventional halogen bulb MR-16 lights.
In various embodiments, reflecting lens 210 and transmissive lens 260 may be formed from a UV and resistant transparent material, such as glass, polycarbonate material, or the like. In various embodiments, reflecting lens 210 or transmissive lens 260 may be clear and transmissive or solid or coated and reflective. In the case of reflecting lens 210, the solid material creates a folded light path such that light that is generated by the integrated LED assembly 220 internally reflects within reflecting lens 210 more than one time prior to being output. Such a folded optic lens enables light 200 to have a tighter columniation of light than is normally available from a conventional reflector of equivalent depth. In the case of transmissive lens 260, the solid material may be clear or tinted, may be machined or molded, or the like to control the output characteristics of the light from reflecting lens 210.
In various embodiments, to increase durability of the lights, the optical materials should be operable at an elevated temperature (e.g. 120 degrees C.) for a prolonged period of time (e.g. hours). One material that may be used for reflecting lens 210 is known as Makrolon™ LED 2045 or LED 2245 polycarbonate available from Bayer Material Science AG. In other embodiments, other similar materials may also be used.
In
In other embodiments, transmissive lens 260 may be secured to heat sink 230 via the clips described above. Alternatively, transmissive lens 260 may first be secured to a retaining ring 270, and retaining ring may be secured to one or more indents of heat sink 230, as will be illustrated below in greater detail. In some embodiments, once transmissive lens 260 and retaining ring 270 is secured to reflecting lens 210 or heat sink 230, they cannot be removed by hand. In such cases, one or more tools must be used to separate these components. In other embodiments, these components may be removed from reflecting lens 210 or heat sink 230 simply by hand.
In various embodiments of the present invention, LED assemblies may be binned based upon lumen per watt efficacy. For example, in some examples, an integrated LED module/assembly having a lumen per watt (L/W) efficacy from 53 to 66 L/W may be binned for use for 40 degree flood lights, a LED assembly having an efficacy of approximately 60 L/W may be binned for use for spot lights, a LED assembly having an efficacy of approximately 63 to 67 L/W may be used for 25 degree flood lights, and the like. In other embodiments, other classification or categorization of LED assemblies on the basis of L/W efficacy may used for other target applications.
In some embodiments, as will be discussed below integrated LED assembly/module 220 typically includes 36 LEDs arranged in series, in parallel series (e.g. three parallel strings of 12 LEDs in series), or the like. In other embodiments, any number of LEDs may be used, e.g., 1, 10, 16, or the like. In other embodiments, the LEDs may be electrically coupled in other manner, e.g. all series, or the like. Further details regarding such LED assemblies are provided in the patent application incorporated by reference above.
In various embodiments, the targeted power consumption for LED assemblies is less than 13 watts. This is much less than the typical power consumption of halogen based MR16 lights (50 watts). Accordingly, embodiments of the present invention are able to match the brightness or intensity of halogen based MR16 lights, but using less than 20% of the energy.
In various embodiments of the present invention, LED assembly 220 is directly secured to heat sink 230 to dissipate heat from the light output portion and/or the electrical driving circuits. In some embodiments, heat sink 230 may include a protrusion portion 250 to be coupled to electrical driving circuits. As will be discussed below, LED assembly 220 typically includes a flat substrate such as silicon or the like. In various embodiments, it is contemplated that an operating temperature of LED assembly 220 may be on the order of 125 to 140 degrees C. The silicon substrate is then secured to the heat sink using a high thermal conductivity epoxy (e.g. thermal conductivity ˜96 W/m.k.). In some embodiments, a thermoplastic/thermo set epoxy may be used such as TS-369, TS-3332-LD, or the like, available from Tanaka Kikinzoku Kogyo K.K. Other epoxies may also be used. In some embodiments, no screws are otherwise used to secure the LED assembly to the heat sink, however, screws or other fastening means may also be used in other embodiments.
In various embodiments, heat sink 230 may be formed from a material having a low thermal resistance/high thermal conductivity. In some embodiments, heat sink 230 may be formed from an anodized 6061-T6 aluminum alloy having a thermal conductivity k=167 W/m.k., and a thermal emissivity e=0.7. In other embodiments, other materials may be used such as 6063-T6 or 1050 aluminum alloy having a thermal conductivity k=225 W/m.k. and a thermal emissivity e=0.9. In other embodiments, still other alloys such AL 1100, or the like may be used. Additional coatings may also be added to increase thermal emissivity, for example, paint provided by ZYP Coatings, Inc. utilizing CR2O3 or CeO2 may provide a thermal emissivity e=0.9; coatings provided by Materials Technologies Corporation under the brand name Duracon™ may provide a thermal emissivity e>0.98; and the like. In other embodiments, heat sink 230 may include other metals such as copper, or the like.
In some example, at an ambient temperature of 50 degrees C., and in free natural convection heat sink 230 has been measured to have a thermal resistance of approximately 8.5 degrees C./Watt, and heat sink 230 has been measured to have a thermal resistance of approximately 7.5 degrees C./Watt. With further development and testing, it is believed that a thermal resistance of as little as 6.6 degrees C./Watt are achievable in other embodiments. In light of the present patent disclosure, it is believed that one of ordinary skill in the art will be able to envision other materials having different properties within embodiments of the present invention.
In various embodiments, base assembly/module 240 in
The shell of base assembly 240 may be formed from an aluminum alloy, and may formed from an alloy similar to that used for heat sink 230 and/or heat sink 230. In one example, an alloy such as AL 1100 may be used. In other embodiments, high temperature plastic material may be used. In some embodiments, instead of being separate units, base assembly 240 may be monolithically formed with heat sink 230.
As illustrated in
In various embodiments, to facilitate a transfer of heat from the LED driving circuitry to the shell of the base assemblies, and of heat from the silicon substrate of the LED device, a potting compound is provided. The potting compound may be applied in a single step to the internal cavity of base assembly 240 and to the recess within heat sink 230. In various embodiments, a compliant potting compound such as Omegabond® 200 available from Omega Engineering, Inc. or 50-1225 from Epoxies, etc., may be used. In other embodiments, other types of heat transfer materials may be used.
In various embodiments, the LEDs 300 are mounted upon a silicon substrate 310, or other thermally conductive substrate. In various embodiments, a thin electrically insulating layer and/or a reflective layer may separate LEDs 300 and the silicon substrate 310. Heat produced from LEDs 300 is typically transferred to silicon substrate 310 and to a heat sink via a thermally conductive epoxy, as discussed above.
In various embodiments, silicon substrate is approximately 5.7 mm×5.7 mm in size, and approximately 0.6 microns in depth. The dimensions may vary according to specific lighting requirement. For example, for lower brightness intensity, fewer LEDs may be mounted upon the substrate, accordingly the substrate may decrease in size. In other embodiments, other substrate materials may be used and other shapes and sizes may also be used
As shown in
As illustrated in
Illustrated in
Various shapes and sizes for FPC 340 are contemplated in various embodiments of the present invention. For example, as illustrated in
In
After the electronic driving devices and the silicon substrate 310 are bonded to FPC 340, the LED package sub assembly or module 220 is thus assembled. In various embodiments, these LED modules may then be individually tested for proper operation.
In various embodiments, the following process may be performed to form an LED assembly/module. Initially, a plurality of LEDs 300 are provided upon an electrically insulated silicon substrate 310 and wired, step 400. As illustrated in
Next, a plurality of electronic driving circuit devices and contacts may be soldered to the flexible printed circuit 340, step 430. The contacts are for receiving a driving voltage of approximately 12 VAC. As discussed above, unlike present state of the art MR-16 light bulbs, the electronic circuit devices, in various embodiments, are capable of sustained high-temperature operation, e.g. 120 degrees C.
In various embodiments, the second portion of the flexible printed circuit including the electronic driving circuit is inserted into the heat sink and into the inner cavity of the base module, step 440. As illustrated, the first portion of the flexible printed circuit is then bent approximately 90 degrees such that the silicon substrate is adjacent to the recess of the heat sink. The back side of the silicon substrate is then bonded to the heat sink within the recess of the heat sink using an epoxy, or the like, step 450.
In various embodiments, one or more of the heat producing the electronic driving components/circuits may be bonded to the protrusion portion of the heat sink, step 460. In some embodiments, electronic driving components/circuits may have heat dissipating contacts (e.g. metal contacts) These metal contacts may be attached to the protrusion portion of the heat sink via screws (e.g. metal, nylon, or the like). In some embodiments, a thermal epoxy may be used to secure one or more electronic driving components to the heat sink. Subsequently a potting material is used to fill the air space within the base module and to serve as an under fill compound for the silicon substrate, step 470.
Subsequently, a reflective lens may be secured to the heat sink, step 480, and the LED light source may then be tested for proper operation, step 490.
In various embodiments, the base sub-assembly/modules that operate properly may be packaged along with one or more transmissive lens offerings and/or a retaining ring (described above), step 500, and shipped to one or more distributors, resellers, retailers, or customers, step 510. In various embodiments, the modules and separate transmissive lenses may be stocked, stored, or the like.
Subsequently, in various embodiments, an end user desires a particular lighting solution, step 520. In various examples, the lighting solution may require different beam angles, different cut-off angles or roll-offs, different coloring, different field angles, and the like. In various embodiments, the beam angles, the field angles, and the full cutoff angles may vary from the above, based upon engineering and/or marketing requirements. Additionally, the maximum intensities may also vary based upon engineering and/or marketing requirements.
Based upon the end-user's application, a secondary transmissive lens may be selected, step 530. In various embodiments, the selected lens may or may not be part of a “kit” for the lighting module. In other words, in some examples, various transmissive lenses are provided with each lighting module; and in other examples, lighting modules are provided separately from the transmissive lenses.
In various embodiments, an assembly process may include attaching the retaining ring to a transmissive lens, and snapping the retaining ring into a groove of the heat sink, step 540. In other embodiments, a retaining ring is already installed for each transmissive lens that is provided.
In some embodiments, once the retaining ring is snapped into the heat sink, clips, or the like, the retaining ring (and secondary optic lens) cannot be removed by hand. In such cases, a tool, such as a thin screwdriver, pick, or the like, must be used to remove the secondary optic lens (transmissive lens) from the assembled unit. In other embodiments, the restraint mechanism may be removed by hand.
In
In
In other embodiments, the transmissive lens may be coupled to a an intermediate grille, or the like that is coupled to the heat sink and/or reflective lens. Accordingly, embodiments of the present invention may be directed towards wide-beam light sources or narrow-beam light sources.
Further embodiments can be envisioned to one of ordinary skill in the art after reading this disclosure. In other embodiments, combinations or sub-combinations of the above disclosed invention can be advantageously made. The block diagrams of the architecture and flow charts are grouped for ease of understanding. However it should be understood that combinations of blocks, additions of new blocks, re-arrangement of blocks, and the like are contemplated in alternative embodiments of the present invention.
The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope.
The present application claims priority to U.S. Provisional Application No. 61/530,832, filed on Sep. 2, 2011, which is incorporated herein by reference for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 61530832 | Sep 2011 | US |
