OPTICAL LIGHTING SYSTEM AND METHOD
20170219202 · 2017-08-03
Assignee
Inventors
Cpc classification
F21V29/763
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V29/87
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S8/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V29/71
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V29/89
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S8/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V7/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V7/041
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21W2131/40
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V7/10
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21Y2115/10
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21Y2107/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F21V29/89
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V7/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S8/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V7/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
An LED lighting array for illuminating an area with the lighting array comprising a plurality of LED devices set in conical or elliptically conical reflectors, each of which is mounted upon a plate, each of which may be set at various angles to one other, and each of which is backed by a series of elements, first a copper support element, then an optional layer of graphite foam, followed by an aluminum plate, and then an arrangement of copper fins operably lined to a thermal mass mate. The copper support element includes support planes that are off-set relative to each adjacent plate and are in at least three different planes relative to each other. The backing plates may efficiently dissipate heat produced by the LEDs. The apparatus can be mounted upon a stand to illuminate an area such as a portion of a car park, building entrance or the like.
Claims
1. A lighting system for illuminating an area, comprising: a plurality of light emitting diode arrays, wherein each of said light emitting diode arrays is disposed within an elliptically conical reflector having an axis and an optically reflective interior surface; and a thermally conductive support structure having an axis; wherein each of said light emitting diode arrays and each of said elliptically conical reflectors are attached to and in thermal communication with said support structure, and wherein said attachment to said support structure is thermally conductive so that heat is transferred from each of said light emitting diode arrays through said support structure to a heat dissipating heat sink, and and wherein at least one of light emitting diode arrays is attached to said support structure such that said the axis of said conical reflector is disposed at a pre-determined angle to said support structure axis.
2. The lighting system of claim 1, wherein said thermally conductive support structure comprises: a base plate comprised of a thermally conductive material and having a first side and a second side; a carbon foam layer; a back plate comprised of a thermally conductive material and having a first side and a second side; and a plurality of heat fins comprised of a thermally conductive material; wherein said light emitting diode arrays are attached to and in thermal communication with said first side of said base plate, said carbon foam is sandwiched between and in thermal communication with said second side of said base plate and said first side of said back plate, and said heat fins are attached to and in thermal communication with said second side of said back plate.
3. The lighting system of claim 1, wherein said base plate is comprised of oxygen-free thermally conductive copper.
4. The lighting system of claim 3, wherein said back plate is comprised of aluminum.
5. The lighting system of claim 4, wherein said heat fins are comprised of copper.
6. The lighting system according to claim 1, wherein a shape, configuration and profile of said reflectors provides a pre-determined non-circular intensity distribution pattern of optical energy on a planar surface when said light emitting diode arrays transmit light.
7. The lighting system according to claim 4, wherein the intensity distribution pattern is a superposition of light reflected from each said reflector and light directed into the lighting intensity distribution pattern directly from the LED array.
8. The lighting system according to claim 1, wherein a shape, configuration and profile of said reflectors provides a pre-determined non-circular asymmetrical lighting intensity distribution pattern.
9. The lighting system according to claim 1, wherein each said reflector axis is disposed at a predetermined angle with respect to each other said reflector axis.
10. The lighting system according to claim 1, wherein said base support member is further divided into a plurality of support plates, each support plate attached to one of said reflectors and one of said light emitting diodes, and wherein each support plate is not coplanar to each adjacent said plate.
11. The lighting system according to claim 10, wherein said plurality of support plates are disposed in at least three different planes relative to each other.
12. The lighting system of claim 1, wherein said thermally conductive support structure comprises at least one light group subassembly having an axis, comprising: an inner support plate having a first side and a second side, comprised of thermally conductive material; an intermediate heat sink plate having a first side and a second side, comprised of thermally conductive material; a heat sink back plate having a first side and a second side, comprised of thermally conductive material; a plurality of graphite foam blocks; wherein said plurality of light emitting diode arrays are attached to and in thermal communication with said first side of said inner support plate, at least some of said plurality of carbon foam blocks are sandwiched between and in thermal communication with said second side of said inner support plate and said first side of said intermediate heat sink plate; and wherein at least some of said plurality of carbon foam blocks are sandwiched between and in thermal communication with said second side of intermediate heat sink plate and said first side of said intermediate heat sink back plate.
13. The lighting system of claim 12, wherein said lighting system is further defined as comprising a plurality of light group subassemblies.
14. The lighting system of claim 13, wherein each of said light group subassemblies is disposed in a circular pattern, each of said light group subassemblies in the circular pattern being evenly distributed in said pattern, and said circular pattern having a center, through which a lighting system axis passes orthogonal to the plane of the circular pattern.
15. The lighting system of claim 14, wherein said axis of each of said light group subassemblies is canted at an offset angle to said lighting system axis to achieve a predetermined lighting intensity distribution pattern.
16. The lighting system of claim 15, wherein said offset angle is twenty degrees.
17. The lighting system of claim 12, wherein said plurality of light emitting diode arrays is further defined as five light emitting diode arrays.
18. The lighting system of claim 13, wherein said plurality of light group subassemblies is further defined as six light group subassemblies.
19. The lighting system of claim 18, wherein said plurality of light emitting diode arrays in each of said plurality of light group subassemblies is further defined as comprising six light emitting diode arrays.
20. A method of illuminating a predetermined area by forming a light intensity distribution pattern on said area, said method comprising the steps of: assembling a plurality of light emitting diode arrays; disposing said plurality of light emitting diode arrays in elliptically conical reflectors, and disposing said plurality of light emitting diode arrays in at least three planes relative to one another; providing electrical power to each of said plurality of light emitting diode arrays to stimulate said light emitting diode array to emit light; wherein the shape, location and orientation of said plurality of reflectors provides a pre-determined combined asymmetrical light distribution pattern on said area; and wherein said light distribution pattern is a superposition of light emitted from said light emitting diode arrays, directly and reflected from said reflectors, onto said area.
21. The method according to claim 20, wherein said step of assembling a plurality of light emitting diode arrays further comprises the step of attaching said plurality of LED arrays and said plurality of reflectors to a thermally conductive support structure comprising: a base plate comprised of a thermally conductive material and having a first side and a second side; a carbon foam layer; a back plate comprised of a thermally conductive material and having a first side and a second side; and a plurality of heat fins comprised of a thermally conductive material; wherein said light emitting diode arrays are attached to and in thermal communication with said first side of said base plate, said carbon foam is sandwiched between and in thermal communication with said second side of said base plate and said first side of said back plate, and said heat fins are attached to and in thermal communication with said second side of said back plate.
22. The method according to claim 21, wherein said base plate is comprised of oxygen-free thermally conductive copper.
23. The method according to claim 20, wherein said step of assembling a plurality of light emitting diode arrays further comprises the step of attaching said plurality of LED arrays and said plurality of reflectors to a thermally conductive support structure wherein said thermally conductive support structure comprises at least one light group subassembly having an axis, said at least one light group subassembly comprising: an inner support plate having a first side and a second side, comprised of thermally conductive material; an intermediate heat sink plate having a first side and a second side, comprised of thermally conductive material; a heat sink back plate having a first side and a second side, comprised of thermally conductive material; a plurality of graphite foam blocks; wherein said plurality of light emitting diode arrays are attached to and in thermal communication with said first side of said inner support plate, at least some of said plurality of carbon foam blocks are sandwiched between and in thermal communication with said second side of said inner support plate and said first side of said intermediate heat sink plate; and wherein at least some of said plurality of carbon foam blocks are sandwiched between and in thermal communication with said second side of intermediate heat sink plate and said first side of said intermediate heat sink back plate.
24. The method according to claim 23, wherein said at least one light group subassembly is further defined as comprising a plurality of light group subassemblies.
25. The method according to claim 24, wherein each of said light group subassemblies is disposed in a circular pattern, each of said light group subassemblies in the circular pattern being evenly distributed in said pattern, and said circular pattern having a center, through which a lighting system axis passes orthogonal to the plane of the circular pattern.
26. The method according to claim 25, wherein said axis of each of said light group subassemblies is canted at an offset angle to said lighting system axis to achieve a predetermined lighting intensity distribution pattern.
27. The method according to claim 26, wherein said offset angle is twenty degrees.
28. The method according to claim 20, further comprising the step of determining a spatial light output distribution of said plurality of LED arrays.
29. The method according to claim 20, further comprising the step of determining a combined light intensity distribution pattern of light energy emitted from said light emitting diode arrays onto an area, said combined light intensity distribution pattern comprising light energy directly radiated onto said area from said plurality of said light emitting diodes, and light energy reflected onto said area by said elliptically conical reflectors, utilizing the shape, location and orientation of said elliptically conical reflectors to determine said combined light intensity distribution pattern.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one or more embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating the preferred embodiments of the invention and are not to be construed as limiting the scope of the invention. In the drawings:
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DETAILED DESCRIPTION OF THE INVENTION
[0066] The following documentation provides a detailed description of the invention.
[0067] Several detailed illustrative embodiments of the present invention are disclosed herein. However, techniques, systems, compositions and operating structures in accordance with the present invention may be embodied in a wide variety of sizes, shapes, forms and modes, some of which may be quite different from those in the disclosed embodiment. Consequently, the specific structural and functional details disclosed herein are merely representative, yet in that regard, they are deemed to afford the best embodiment for purposes of disclosure and to provide a basis for the claims herein which define the scope of the present invention.
[0068] Various aspects of the present invention will be described herein with reference to drawings that are schematic illustrations of idealized configurations of the present invention. As such, variations from the shapes of the illustrations as a result, for example, manufacturing techniques and/or tolerances, are to be expected. Thus, the various aspects of the present invention presented throughout this disclosure should not be construed as limited to the particular shapes of elements (e.g., regions, layers, sections, substrates, etc.) illustrated and described herein but are to include deviations in shapes that result, for example, from manufacturing. By way of example, an element illustrated or described as a rectangle may have rounded or curved features and/or a gradient concentration at its edges rather than a discrete change from one element to another. Thus, the elements illustrated in the drawings are schematic in nature and their shapes are not intended to illustrate the precise shape of an element and are not intended to limit the scope of the present invention.
[0069] It will be understood that when an element such as a region, layer, section, substrate, or the like, is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. It will be further understood that when an element is referred to as being “fainted” on another element, it can be grown, deposited, etched, attached, connected, coupled, or otherwise prepared or fabricated on the other element or an intervening element.
[0070] Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element's relationship to another element as illustrated in the drawings. It will be understood that relative terms are intended to encompass different orientations of an apparatus in addition to the orientation depicted in the drawings. By way of example, if an apparatus in the drawings is turned over, elements described as being on the “lower” side of other elements would then be oriented on the “upper” side of the other elements. The term “lower”, can therefore, encompass both an orientation of “lower” and “upper,” depending of the particular orientation of the apparatus. Similarly, if an apparatus in the drawing is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.
[0071] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and this disclosure.
[0072] As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The term “and/or” includes any and all combinations of one or more of the associated listed items.
[0073] As used herein, the term “elliptically conical” shall mean a cone having a length, a longitudinal axis, a small end having opening, and a large end having an opening, where the cone small end opening comprises a circle having a center and the cone large end opening comprises an ellipse having a center, and wherein the cone small end circle center and the cone large end ellipse center lie substantially on the longitudinal axis of the cone.
[0074] Whereas the embodiments presented below are described in terms of an LED or an array of LEDs, for a light source, any other light sources that may be approximately represented as point light sources may be contemplated as well within the scope and intent of the disclosure, including lasers, light emitting bulbs, and the like. As used herein, an array of LEDs may comprise one or more LEDs.
[0075] Reference will now be made in detail to several embodiments of the invention that are illustrated in the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. For purposes of convenience and clarity only, directional terms, such as top, bottom, up, down, over, above, below, etc., or motional terms, such as forward, back, sideways, transverse, etc. may be used with respect to the drawings. These and similar directional terms should not be construed to limit the scope of the invention in any manner
The Embodiments of the Invention
[0076] A first embodiment of the invention, primarily intended primarily, but not exclusively, for outdoor use such as in illumination of parking lots, athletic fields, and the like is first described. Next, a second embodiment of the invention intended primarily, but not exclusively, for indoor use such as in illumination of indoor high bay assembly facilities, museums, large public buildings, hangars, churches and the like is next described.
Description of the First Embodiment of the Invention
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Description of the Second Embodiment of the Invention
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[0097] The system of the invention may further comprise a plurality of light fixture assemblies 001 of the second embodiment of the invention in a typical application in which they are equally spaced apart and suspended from the ceiling of a building such as a museum, high bay assembly facility, or the like is depicted. The plurality of light fixture assemblies 001 of the second embodiment of the invention provide a desired light intensity distribution pattern over any desired area. The ability to achieve a desired light intensity distribution pattern over any desired area is important for any number of operations such as manufacturing and assembly operations, museums and displays, and the like.
[0098] The method of the invention comprises a method of illuminating a predetermined area by forming a desired light intensity distribution pattern on the area, comprising the steps of assembling a plurality of light emitting diode arrays; disposing the plurality of light emitting diode arrays in elliptically conical reflectors, and disposing the plurality of light emitting diode arrays in at least three planes relative to one another; providing electrical power to each of said plurality of light emitting diode arrays to stimulate the light emitting diode array to emit light at a desired intensity; wherein the shape, location and orientation of the plurality of reflectors provides a pre-determined combined asymmetrical light distribution pattern on the area; and wherein the light distribution pattern is a superposition of light emitted from the light emitting diode arrays, directly and reflected from the reflectors, onto the area.
[0099] The method may further be defined by the step of assembling a plurality of light emitting diode arrays further comprising the step of attaching the plurality of LED arrays and said plurality of reflectors to a thermally conductive support structure comprising a base plate comprised of a thermally conductive material and having a first side and a second side; a carbon foam layer; a back plate comprised of a thermally conductive material and having a first side and a second side; and a plurality of heat fins comprised of a thermally conductive material; wherein the light emitting diode arrays are attached to and in thermal communication with the first side of the base plate, the carbon foam is sandwiched between and in thermal communication with the second side of the base plate and the first side of said back plate, and the heat fins are attached to and in thermal communication with the second side of the back plate.
[0100] The method of the invention may be further defined as the base plate being comprised of oxygen-free thermally conductive copper.
[0101] The method may further be defined by the step of assembling a plurality of light emitting diode arrays further comprising the step of attaching the plurality of LED arrays and the plurality of reflectors to a thermally conductive support structure wherein the thermally conductive support structure comprises at least one light group subassembly having an axis, the at least one light group subassembly comprising: an inner support plate having a first side and a second side, comprised of thermally conductive material; an intermediate heat sink plate having a first side and a second side, comprised of thermally conductive material; a heat sink back plate having a first side and a second side, comprised of thermally conductive material; and a plurality of graphite foam blocks; wherein said plurality of light emitting diode arrays are attached to and in thermal communication with the first side of said inner support plate, at least some of the plurality of carbon foam blocks are sandwiched between and in thermal communication with the second side of said inner support plate and the first side of the intermediate heat sink plate; and wherein at least some of the plurality of carbon foam blocks are sandwiched between and in thermal communication with the second side of intermediate heat sink plate and the first side of the intermediate heat sink back plate.
[0102] The method may further be defined by the at least one light group subassembly being further defined as comprising a plurality of light group subassemblies.
[0103] The method may further be defined by each of the light group subassemblies being disposed in a circular pattern, each of the light group subassemblies in the circular pattern being evenly distributed in the pattern, and the circular pattern having a center, through which a lighting system axis 900, shown in
[0104] The method may further be defined by the axis of each of the light group subassemblies being canted at an offset angle to the lighting system axis to achieve a predetermined lighting intensity distribution pattern, and further, the offset angle being twenty degrees.
[0105] The method may further be defined as further comprising the step of determining a spatial light intensity distribution of the plurality of LED arrays.
[0106] The method may further be defined as further comprising the step of determining a combined light intensity distribution pattern of light energy emitted from the light emitting diode arrays onto an area, the combined light intensity distribution pattern comprising light energy directly radiated onto said area from the plurality of the light emitting diodes, and light energy reflected onto said area by the elliptically conical reflectors, utilizing the shape, location and orientation of said elliptically conical reflectors to determine the combined light intensity distribution pattern.
[0107] As described above and depicted in the figures, the various embodiments of the present invention are designed to be operative as a controllable intelligent lighting fixture. That is, the current technology uses timers which are inefficient, and prone to error. On the other hand, the present invention provides an intelligent lighting fixture, utilizing a microcontroller application such that the system turns light on in graduating sequence with decreasing ambient light, turns light off in graduating sequence with increasing ambient light, is optionally programmable via and external device (e.g., an IPAD or other mobile electronic communication device), provides an additional 15-20% in economic savings and 15-20% in additional energy savings.
[0108] In a first study of parking lot luminaires, the initial conditions were 12 metal halide luminaires at 520 W, for a cost of $0.15 per Kw, which is an annual cost of approximately $2,000-4,000 depending upon the general installed and integrated version. After switching to a lighting system according to the present invention, i.e., 12 LED luminaires at 43 W, for a cost of $0.15 per Kw, and a projected annual cost of $330, the result was a greater than 90% savings where the luminaire sell price is $825.
[0109] In a second study of flood lights, the initial conditions were 12 metal halide bulbs at 100 W, for a cost of $0.15 per Kw, which is an annual cost of $520 (i.e., cost of replacement). After switching to a lighting system according to the present invention, i.e., 12 LED luminaires at 15 W, for a cost $0.15 per Kw, and a projected annual cost of $77, the result was a greater than 85% savings.
[0110] Also, when comparing the lighting efficiency and coverage of the lighting system according to the invention versus a competing lighting system using a parking lot light as an example, the first known system was a Lithonia LED light system at 109 W providing a coverage area of 8,800 sq. ft. Where a lighting system in accordance with the invention is used, with only 43 W, a coverage area of 15,000 sq. ft. is provided, which is approximately a 60% savings. Similarly, in a second comparison using a 400 W metal halide parking lot light at 520 W to provide a coverage of 15,000 sq. ft. (Metal halides are the current standard lighting used in 90+% of existing parking lot lights), an LED parking lot light system or assembly according of the invention uses only 43 W to provide the same coverage of 15,000 sq. ft., which yields a 92% savings.
[0111] Also described is a comparison between a next generation LED luminaire with a 400 W metal halide HID lamp. Initially, 12 metal halide luminaires were used around a building, with each 400 W bulb and ballast system consuming between 500-520 W (measured and verified by two means, using a current meter and calculated via a direct amperage measurement with a multi-meter in series and then taking a voltage measurement for that luminaire) The installed features were harsh to the viewer and a more efficient, greener, and more visibly pleasing design could be produced. First, the ground area to be illuminated was evaluated. Second, one lamp was segregated and the amount of light reaching the ground over 5 foot increments left and right and forward and rear of the pole were measured. Resulting were a best case and worst case for light output since the measured system was running for some amount of time.
[0112] The initial Lumen value of the 400 W (500-520 W measured) metal Halide bulb technology is well over 35,000 lumens. The “lifetime” of a metal halide bulb can range anywhere from 8,000 hours onward. Depending on how the bulb is installed (horizontal or vertical) the lumen depreciation can be decreased by 20% in the first 2,000 hours. The amount of trapped light (light not reaching an intended targeted surface) can range from 24% to upwards of 58% depending on the style and shielding pattern of the optics.
[0113] A well designed and well balanced LED system will have a loss of light over the first 10,000 hours of less than 2%. Provided is test data according Nichia (LED manufacturer used in the lighting technology of the present invention) for samples of the LED used in the design, e.g., 88° C. ambient, 88° C. LED junction temperature test point, and drive current of 693 mA. The samples under the test lost approximately 4% over the 10,000 hours. The test performed by Nichia used a set of parameters that are several times above the running current of the design according to the present invention and calculations show that the junction temperature of the present invention are approximately 20° C. above ambient under most conditions. The combination of the LEDs are run (i.e., current level) and multi stage heat sink design contribute to the consistent performance achieved by the design according to the present invention.
[0114] The custom designed optics according to the invention contribute to the overall efficiency of the lighting design. The amount of trapped light within the design is near 0%, as there are some normal losses due to reflections as the light leaves the housing but such losses are small. Preferably, each LED is oriented to illuminate a specific area on the ground with enough overlap so the resultant coverage area is even. In an isofootcandle chart for a brand new 400 W (i.e., 500-520 W measured) metal halide lamp, after approximately 2,000 hours the area directly beneath the bulb reads approximately 3-4 fc and the overall illuminated area is diminished by upwards of 25%. In an isofootcandle chart showing the light according to the present invention mounted at the same height as the original metal halide, the same coverage area is achieved with only 4,000 lumens of light.
[0115] The easiest way to confirm the function, efficiency and effectiveness of an LED design is by thermal performance The LED requires a thermal state to be maintained at reasonable levels, which include the amount of heat generated by the LED that must be removed from the system as efficiently as possible. The heat sink design in accordance with the preferred embodiment of the invention allows the heat generated by the LED to be removed from the package area very quickly. That is, each stage of the heat sink transfers the thermal energy to the light fixture chassis. To verify the LED design the junction temperature (T.sub.j) of the LED was measured while running at the desired current. The LED had a test point which was directly connected to the die of the package. The following calculation was then applied to obtain the T.sub.j of the LED package:
[0116] T.sub.j=T.sub.c+RΘ.sub.jc *W (where T.sub.j is LED junction temperature in ° C., where T.sub.c is test point temperature in ° C., where RΘ.sub.jc is the thermal resistance from the junction to a T.sub.c measuring point in ° C./W, and where W is the input power in watts);. We then apply our test conditions to the equation and come up with the following data points: T.sub.j =42.5 ° C.+1.7° C./W *4.78 W; and T.sub.j =50.626° C. (where ambient temperature was 21° C., where a thermal resistance of 1.7° C./W was used as a worst case scenario, and where the actual T.sub.j could be as low as 49.19° C. using a typical value of 1.4° C./W). Accordingly, the system and method of the present invention substantially reduces the energy consumption of a wide range of lighting fixtures including those using LEDs, and reduces maintenance and replacement cost due to the extended lifetime.
[0117] On average the T.sub.j of each LED is 20° C. above ambient verifying that the design is sound and allows a lifetime and performance in any climate. The industry standard for life testing LEDs is called TM-21, and such TM-21 testing has been performed by Nichia on the LED being used in design of the present invention. The calculations and data set are below.
TABLE-US-00001 Time Ln (avg.) 0 h 0 496 h −0.0281 1014 h −0.0269 1701 h −0.0336 2441 h −0.0332 3132 h −0.0319 3819 h −0.0372 4485 h −0.0368 5200 h −0.0400 6008 h −0.0411 6817 h −0.0397 7603 h −0.0391 8436 h −0.0422 9198 h −0.0438 10009 h −0.0446 Curve-fit equation: Ø(t) = B.sup.(−αt); Lumen maintenance life equation: L70 = ln(B/0.7)/α.
[0118] Typically LED manufactures conduct TM-21 testing for either 6,000 hours of 10,000 hours. Once the test is performed the life time is then extrapolated by 6 times and that becomes the reported L70 value. Such a test has been performed on the completed fixture according to the present invention. The initial testing performed by NICHIA, a typical LED manufacturer, allows for verification of the present design and provides a starting point. Applicant's related testing is similar to such thermal and time based testing.
[0119] Thermal testing results for a multi-stage heat sink, such as the one used in accordance with the present invention, demonstrate the effectiveness of the heat sink technology of the present invention. The test was performed within a closed system with no external thermal path. The test LED was attached to a 76.2 millimeter (mm)×50.8 mm copper base which was 0.81 mm thick. Probes were directly attached to the test pad that reports a value to calculate the T.sub.j of the die which was discussed above. Stage 1 demonstrates how the LED behaves within the system with no additional thermal mass other than the copper base. When the system reached a steady thermal state the second level of heat sink was added (i.e., stage 2). An immediate drop in temperature was observed, but once the system was saturated and reached an equilibrium point the final stage was added. The final temperature delta between LED and copper only to LED, copper, and full heat sink was 16° C. When the LED thermal path is actually attached to the thermal mass of the light fixture the T.sub.j value will be drastically reduced again.
[0120] A sample cost analysis of the above testing example (e.g., Metal Halide 400 W (500 W -520 W with ballast) is as follows:
TABLE-US-00002 Single System Multiple Systems Number of Units 1 12 Power (W) 500 6,000 Hours on per day 12 144 Kwh 6 72 Energy cost ($) $0.15 $1.8 Daily cost ($) $0.9 $10.8 Monthly cost ($) $27 $324 Yearly cost ($) $324 $3,888
[0121] Thus, the Return On Investment after installing the lighting system of the invention is approximately 2-3 years. A possible second testing may involve 200 W metal halide bulbs which may further decrease system power to 20 W while still keeping a ROI of less than 3 years.
[0122] Color temperature and the shift in color over time are two very important factors when considering luminaires of any type. Metal halide bulbs usually advertise a color temperature of around 4,000-5,000 K, yet their apparent color temperature looks much higher due to the spikes that occur within their spectral distribution in the blue regions. Also, the color temperature of a metal halide lamp will change drastically over its lifetime. Preferably used are white LEDs with a color temperature of approximately 3,900-4,000 K and a CRI of at least 85. Such a color temperature works very well for both comfort level and glare control. Many LED manufacturers use LEDs with very high color temperatures to give the perceived feeling of increased brightness due to the eyes sensitivity to the blue region of the visible spectrum.
[0123] Thus, the present invention provides an innovative LED luminaire that surpasses technologies like metal halide, high pressure sodium, induction, and any other “bulb” like technology on the market today. Deviation from the normal LED luminaire design achieved an optical system which surpasses the traditional normal LED grid array. The lifetime of the lighting fixtures or assembly according to the present invention surpasses 185,000 hours and provides a lighting method and system that will provide quality light for years to come.
[0124] Such LED arrays are preferably recyclable and free of toxic metals such as lead and mercury which are found in conventional HID lighting. The prior lighting fixtures to be replaced suffer from substantial loss of brightness quickly over relatively short life and produce trapped light which does not escape the housing due to inefficiencies with the technology. Because of the >10 year life expectancy of the LED array of the present invention there may be a significant land fill reduction as compared to with HID lighting fixtures in which one could expect to re-lamp 5 times over that same time period.
[0125] In the claims, means or step-plus-function clauses are intended to cover not only the structures described or suggested herein as performing the recited function, but all equivalent structures. Thus, for example, although a nail, a screw, and a bolt may not be structural equivalents in that a nail relies on friction between a wooden part and a cylindrical surface, a screw's helical surface positively engages the wooden part, and a bolt's head and nut compress opposite sides of a wooden part, in the environment of fastening wooden parts, a nail, a screw, and a bolt may be readily understood by those skilled in the art as equivalent structures.
[0126] Having described at least one of the preferred embodiments of the present invention with reference to the accompanying drawings, it is to be understood that such embodiments are merely exemplary and that the invention is not limited to those precise embodiments, and that various changes, modifications, and adaptations may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims. The scope of the invention, therefore, shall be defined solely by the following claims. Further, it will be apparent to those of skill in the art that numerous changes may be made in such details without departing from the spirit and the principles of the invention. It should be appreciated that the present invention is capable of being embodied in other forms without departing from its essential characteristics.
INDUSTRIAL APPLICABILITY
[0127] The several objects of the Optical LED Lighting System and Method of the invention are: to provide a new and improved LED light assembly which efficiently uses a high-output LED to produce highly favorable illumination characteristics for areas desired to be lighted, such as assembly buildings, car parks, and the like; to provide an improved lighting fixture, system and method utilizing the next generation LEDs to provide improved LED heat management, reduced energy consumption, and which maximizes the advantages of LED lighting; to provide a lighting fixture, system and method having a performance advantage over traditional lighting solutions and other known LED lighting solutions; to provide a multi-reflector LED lighting fixture having a longer life than traditional lighting solutions depending upon the LED quality and junction temperature management (i.e., providing junction temperatures substantially lower than other LED lighting solutions); to provide a system and method for an LED lighting system and method providing lower maintenance costs due to longer life spans thereof; to provide a system and method for an LED lighting system that typically last two times longer than traditional LED lighting solutions, and have significantly lower operating costs by requiring less maintenance and less frequent replacement; to provide a novel multi-reflector LED lighting fixture or solution using the highest quality LED arrays, leveraging color and light distribution characteristics of various LED arrays, managing the junction temperature of the LED arrays utilizing proprietary technology, and employing unique methodologies to further reduce energy consumption; and to provide an enhanced method and system for lighting solutions for parking facilities, vehicle dealerships, university facilities, government or municipal facilities, warehouse facilities, athletic fields or facilities, etc.