LED lighting modules and luminaires incorporating same

LED lighting modules have a highly thermally conductive polyhedral body having a plurality of exterior facets disposed around a mounting axis in a polygonal array facing outwardly away from the mounting axis and at a downward angle thereto. At least a majority of the facets carries at least one LED whose optical axis is angled acutely. The body carries a plurality of heat dissipating fins and serves as a heat sink to prevent overheating the LEDs in a transient and steady state operation. For retrofit applications, the module is mounted to a fixture via either a support or a bracket in a mounting position in which the elevation of the LEDs is determined according to the mounting and geometry of the replaced lamp.

STATEMENT REGARDING FEDERALLY SPONSORED-RESEARCH OR DEVELOPMENT

Not Applicable.

INCORPORATION BY REFERENCE

The disclosures of U.S. Design patent application Ser. No. 29/343,692 filed Sep. 17, 2009 and U.S. Design patent application Ser. No. 29/343,695, filed Sep. 17, 2009 and U.S. patent application Ser. No. 12/559,075, filed Sep. 14, 2009 are each expressly incorporated herein by reference in their entirety to form part of the present application as if fully set forth herein Not Applicable.

FIELD OF THE INVENTION

The invention relates to the field of lighting modules and luminaires for general illumination or architectural illumination of indoor or outdoor areas using light emitting diodes (LEDs). More particularly, the invention relates to retrofitable LED lighting modules for installation in a light fixture as an energy efficient replacement for a conventional lamp and to luminaires incorporating such modules.

BACKGROUND OF THE INVENTION

Conventional incandescent light bulbs have a glass envelope which is evacuated or is filled with an inert gas such as argon and/or nitrogen. A thin filament of tungsten is suspended inside the envelope between a pair of electrical leads. Light is produced by passing an electric current through the filament which is heated by the current passing through it until it glows brightly, a process called “incandescence”. Filament temperatures on the order of about 4,500 degrees Fahrenheit (2,500 degrees Celsius) are typical. Incandescent light bulbs are a relatively inefficient way of converting electrical power which is typically measured in Watts, into light which is typically measured in Lumens. The “efficiency” of a lamp is generally expressed according to the amount of visible light the lamp produces as measured in units called “lumens”, divided by the electrical power, measured in “watts”, required to operate the lamp. A lamp with a high ratio of lumens per watt is more energy efficient than one with a lower output of lumens of light per watt of electrical energy consumed. Of the total amount of electrical energy they consume, incandescent lamps convert a much higher percentage of that energy into heat than visible light. Incandescent lamps also have relatively short normal operating lives. After only about 750 to 1,000 hours enough tungsten evaporates from the filament of an incandescent lamp that the filament can no longer support its own weight, causing the lamp to “burn out” as a result of breakage of the filament.

A halogen lamp is an improved type of incandescent lamp. Its tungsten filament is enclosed in a low-volume, gas-filled envelope of quartz. The envelope and the filament are so close to one another that the envelope would melt if it were of ordinary glass. The gas within the envelope is a halogen. At the high normal operating temperatures of a halogen lamp, the gas combines with tungsten that has vaporized off the filament and re-deposits the tungsten back onto the filament, thus both lengthening its life allowing the filament to operate at a significantly higher temperature and thus glow more brightly than an ordinary incandescent bulb. As a result, halogen lamps produce more useful light per unit of electrical power applied to the lamp, i.e. more lumens per watt than a normal incandescent lamp. However, due to their high operating temperature, halogen lamps also waste a large amount of energy that is given off as heat.

Gas discharge lamps of various kinds are also well-known in the prior art. These too include a gas-filled envelope but not have a filament. A fluorescent lamp one type of gas discharge lamp that is widely used. The glass envelope in fluorescent lamp is a typically a glass tube. A small amount of mercury and an inert gas, such as argon, are sealed inside the tube under very low pressure. The inside wall of the tube is coated with a phosphor powder. Each one of a pair of electrodes located at opposite ends inside the tubular glass envelope is wired to a fixture which contains an electrical circuit called a “ballast” that generates a high voltage between the electrodes. That voltage causes electrons to flow through the gas between the electrodes and vaporizes the mercury in the tube. Electrons and mercury atoms collide, raising electrons to higher energy levels. Photons are released as the electrons return to a lower original energy level following those collisions thereby creating light, much of it being invisible ultraviolet (“UV”) light, rather than useful visible light. However, when these photons strike the phosphor coating inside the tube, the phosphor coating releases light within the visible range of the spectrum through a process called “phosphorescence.” Because they convert what would otherwise be invisible UV light into useful visible light, fluorescent lamps are typically much more energy efficient than incandescent lamps.

LEDs produce light by a completely different mechanism than incandescent or gas discharge lamps. An LED is a semiconductor device, namely a diode junction between a p-type semiconductor material and n-type semiconductor material. As an electric current is passed in the forward direction across the p-n junction of an LED, photons are given off as electrons making up the flow of current change their energy levels, thus producing light. This process, called electroluminescence, is an efficient way of generating light from electricity, particularly in comparison to incandescent bulbs and many other types of lamps. However, it is not a process which results in 100% conversion of electrical energy into light. A significant fraction of the energy represented by the electric current flowing through an LED generates heat rather than light. If sufficient amounts of heat are not carried away from the area of the p-n junction at a sufficient rate, the operating temperature of the LED can quickly rise to an unacceptably high temperature which could cause the LED to fail prematurely. Thus, unlike incandescent bulbs and certain other technologies such as high intensity discharge (HID) lamps, which not only tolerate, but actually require, extreme temperatures in order to generate light, LEDs are relatively intolerant of high temperatures, particularly if one desires to maximize the operating life if the LED.

Early LED devices were not capable of producing light in amounts sufficient for general illumination or architectural illumination. They were used mainly as glowing indicators in electronic and consumer devices. However, as a result of advancements in LED technology, LEDs of sufficient light output for flashlights, lanterns and even general and architectural lighting devices have now been available for several years and the technology continues to advance providing new generations of LEDs having greater lumen output, higher efficiency and lower cost than earlier generations. There has been considerable interest in developing LED lighting modules and luminaires which exploit these improvements in LED technology to provide energy cost savings in general and architectural lighting applications. The enormous investment represented by luminaires and light fixtures which are already existing and installed in the field were designed for operation with an incandescent, fluorescent, gas discharge or other conventional type of lamp, has generated considerable interest in developing LED lighting devices which incorporate high intensity LEDs and can be retrofitted into an existing style of light fixture or luminaire as a substitute for a replaced lamp of some other type. However, due in significant part to the inherent intolerance of high temperatures which is characteristic of LEDs, such efforts have met with only limited success.

One approach has been to provide LED luminaires with substantial vent openings which allow air exchange between the interior of the luminaire and the external environment. While vent opening are frequently present in many existing fixtures or luminaires, their sizes and locations are typically not adequate to provide sufficient air exchange to avoid overheating LEDs to a point which at least shortens their operating life. Enlarging and/or relocating vent openings to provide more air flow is not always possible or desirable. By their nature, vent openings can allow for intrusion of dirt, water and/or insects which can damage a fixture or reduce its light output.

As exemplified for example by U.S. Pat. Nos. 7,438,440 and 7,494,248 another approach to dealing with the heat sensitivity of LEDs in luminaires and light fixtures for general and architectural lighting applications has been to connect one or more heat pipes in a thermal path between one or more of the LEDs and a heat sink located exterior to the housing of the fixture or luminaire so as to conduct heat rapidly away from the LED to the external environment. While effective from a thermal management standpoint, fixtures and luminaires constructed in this manner tend to be bulky, complex and relatively expensive to manufacture. Space constraints and the need to modify an existing fixture or luminaire to accommodate the routing of heat pipes make such an approach less than ideal for retrofit applications.

SUMMARY OF THE INVENTION

According to a preferred embodiment, an LED lighting module has a polyhedral body having a plurality of downwardly angled facets disposed in a polygonal array around a mounting axis. At least one LED is supportedly mounted to each respective one of a majority of the facets, each LED having an optical axis oriented at an acute angle with respect to the mounting axis. A plurality of heat dissipating fins are supportably mounted to the body and thermally conductively coupled thereto. According to certain embodiments, an active cooling device is mounted in a recess formed among the fins. The active cooling device may preferably comprise a device of the type which includes a plurality of nozzles each of which discharge successive jets of turbulent pulses to enhance heat transfer from the fins. According to certain embodiments, the body of the module is suspended in its operating position by a mounting bracket while in other embodiments, the body of the module is mounted on a support which preferably also includes a plurality of heat dissipating fins. According to a further aspect of the invention, a light shield having a reflective surface may extend outwardly from one or more of the facets to block at least some light emitted by the LEDs in a skyward direction and redirect same in a downward direction. According to another aspect of the invention, the polyhedral body has sufficient thermal mass, and the LEDs are coupled to the polyhedral body by way of thermally conductive paths of sufficiently low thermal resistance that during the thermal lag period which occurs between the time the LEDs are initially energize and such later time as heat drains from the polyhedral body at a rate at least as raid as that at which heat enters the body from the LEDs, the polyhedral body is capable of taking on heat from the LEDs at a sufficiently high rate of heat flow to prevent overheating of the LEDs.

Further aspects of the invention relate to the elevational positioning of the module with reference to the actual or intended positioning of a lamp which the module replaces or is to be used in lieu of. According to one such aspect, an LED module to be used in a fixture or luminaire instead of a replaced lamp in a base-up orientation, the operating position of the module is such that the center of at least some of the LEDs are positioned at an elevation which substantially corresponds to a midpoint of the major dimension of the envelope of the replaced lamp or at least within a range which is centered about such midpoint and extends over not more than about twenty five percent (25%) of the major dimension of the envelope of the replace lamp.

According to embodiments in which module10is to be used in lieu of a horizontally mounted replaced lamp, the centers of at least some of the LEDs are positioned at an elevation which substantially corresponds to the central axis of the envelope of the replaced lamp.

According to embodiments in which module10is to be used in lieu of a lamp oriented base-down, the mounting bracket or support, as the case may be, positions the polyhedral body such that the centers of at least some of the LEDs on the facets are positioned at an elevation which substantially corresponds to the elevation of the top of the envelope of the replaced lamp or at some lower elevation lying no further below the elevation of the top of the envelope of the replaced lamp than a distance of twenty five percent (25%) of the major dimension of the envelope of the replaced lamp.

These and other objects of the invention will be clear to a person of ordinary skill in the art in light of the following written description of preferred embodiments and the drawings in which corresponding items are designated by corresponding reference numerals.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring collectively toFIGS. 1 through 5, a first preferred embodiment of an LED lighting module10constructed according to the present invention includes an elongated, hollow, support12having an externally threaded upper end14and an externally threaded lower end16which are separated from one another by an unthreaded middle portion18which terminates in an upper collar20and a lower collar22. Extending radially outwardly from middle portion18are a plurality of heat dissipating fins28, which are separated from one another by spaces30located therebetween to facilitate the transfer of heat from support12to the air which contacts fins28. The hollow interior of support12forms a first passage32of adequate cross sectional area to allow at least one or more electrical conductors33,34to be safely routed internally through the entire length of support12by way of first passage32for grounding, powering and/or controlling module10. First passage32protects the conductors33,34from mechanical damage and excessive temperatures and conceals the conductors33,34from view from the exterior of a light fixture36to which module10has been installed, either originally, or as a replacement for a lamp and lampholder which have been removed or in lieu of which module10is being used. In either case, such lamp is referred to hereinafter for the sake of convenience as a “replaced lamp.”

Module10is mounted in an installed position to a housing35of a light fixture36by way of support12. As illustrated inFIG. 2, in the preferred embodiment this is achieved by passing the threaded lower end15of support12through an opening37in light fixture36and mechanically coupling the support12to the housing36by clamping a portion of the housing35between lower collar22and a washer38under pressure exerted by a threaded fastener39, such as a conventional nut, a “Tinnerman” fastener or the like. Alternatively, module10can be secured to fixture36with a snap ring could be applied to engage a groove (not shown) formed in the lower end of15of support12. Yet another alternative is to secure collar22to housing35using one or more rivets, screws, bolts or other suitable mechanical fasteners (not shown) or by welding, brazing, soldering or adhesive bonding.

Support12is formed of a highly thermally conductive material such as aluminum, copper or an alloy such as brass. Support12could be suitably be assembled by joining two or more separate component parts but for best heat transfer, mechanical strength and visual appearance, support12is preferably fabricated as unitary structure formed from a single piece of highly thermally conductive material. In the preferred embodiment support12is machined from a single block of T-6061 aluminum alloy which, after machining, is polished and anodized to resist oxidation and provide an attractive appearance. Support12could alternatively be formed as an aluminum or zinc die casting, sand casting or investment casting of brass or other copper alloy, drilled or otherwise hollowed to form first passage32. Support12could be formed by pressing a quantity of powdered metal or a composite material into shape and sintering it to fuse the powder into an integrated structure or in any of a variety of other ways which will become apparent to a person of ordinary skill in the art in light of the disclosure set forth herein and in the drawings.

Module10further includes a polyhedral body40which has a mounting axis47and is supportably mounted to the upper end15of support12. In the preferred embodiment, mounting axis40happens to be oriented vertically and coincides with the central longitudinal axis of support12. It is to be understood however, that the orientation of the mounting axis47and the orientation of the support12and the geometry and manner according to which it is joined to body40can be varied to best suit the needs of a given application. It is also to be understood that support12is not limited to a columnar, or post-like configuration or any particular shape. Support12could, by way of nonlimiting example, alternatively be formed as a tripod or as a bifurcated member of a generally upright, or inverted letter “Y”-shaped member or assembly of members. Also, body40need not be supported solely by support12. Support of body40can be carried out with the aid of one or more additional supports12and/or other members without departing from the scope of the invention.

Body40has an underside42, the center of which is penetrated by a female threaded opening which mates with the threaded upper end15of support12to securely mechanically couple body40and support12to one another and thermally and conductively couple body40and support to one another so there is, at most, little thermal resistance between them. In addition to a substantial mating surface area present between body50and support12at the interface of the male threads carried by the upper end14of support12and the female threads of opening52, the upper collar20of support12has a flat, smooth, upper surface43which abuts a mating portion of the underside42of body50over a relatively large area and thus serves to even further reduce the thermal resistance between support12and body50. If desired, a heat transfer enhancing agent, such as thin layer (not shown) of thermally conductive paste of the type commonly used for mounting semiconductor packages on circuit boards, may be interposed between the underside42of body40and the upper surface43of upper collar20to reduce the thermal resistance between body40and support12by filling any small gaps, which may exist therebetween.

Polyhedral body40is formed of a highly thermally conductive material which, in order to avoid galvanic corrosion and/or loosening due to differences in thermal coefficients of expansion, is preferably of the same material as support12. Accordingly, in the preferred embodiment, body40is fabricated by machining from a single block of T-6061 aluminum alloy and is polished and anodized after machining. Body40could also be formed from brass or other alloys of copper or other alloys and could suitably be fabricated using any of the alternative fabrication techniques mentioned above in connection with the fabrication of support12.

Body40has sufficient thermal mass, and the thermal paths90-99by way of which LEDs60-69are thermally conductively coupled to body40are of sufficiently low thermal resistance, to keep the temperature of LEDs60-69acceptably low during the transient thermal lag period which occurs between the time any or all of LEDs60-69are first energized and such later time that the temperature of body40stops rising as a result of heat being shed from body40by any combination of thermal conduction convection and/or, radiation, either directly from body40itself or by way of one or more other components of module10such as heat dissipating fins28and/or49and light shields116.

A plurality of heat dissipating fins49are supportably mounted to body40and are thermally conductively coupled to polyhedral body40. In the preferred embodiment, fins49take the form of a plurality of mutually spaced, parallel plates having air gaps between them to facilitate the transfer of heat from body40to the ambient environment which adjoins fins49. Fins49are preferably of a highly thermally conductive material and are preferably integrally formed with body40by being machined from the same piece of stock material from which body40itself is fabricated. Alternatively, fins49could be formed as separate plates which could be welded, soldered or brazed to body40or shrink fitted into parallel slots formed in the top of body40.

Polyhedral body40also includes a plurality of exterior planar facets55,56,57,58and59which are arranged in a substantially polygonal array52. Facets55-59each face outwardly away from mounting axis47and are oriented at a downward angle with respect to mounting axis47as shown inFIG. 2. In the preferred embodiment, polygonal array52is a pentagonal array whose cross sectional profile is a pentagon53which happens to be centered on mounting axis47as can be seen for example fromFIG. 3. It is to be understood however that embodiments in which body40has more than five (5 ea.) facets, or fewer than five (5 ea.) facets, are also within the scope of the present invention, the number of facets being selected primarily based on the overall lighting distribution pattern desired to be projected from module10.

At least a majority of the total number of downwardly angled facets55-59on polyhedral body40have at least one light emitting diode (LED) supportably mounted thereon. As used herein and in the claims, the term “LED” is to be broadly construed and includes light emitting diodes made using either organic materials, such as OLEDs and/or PLEDs or inorganic semiconductor, all without limitation as to the particular wavelength or combination of wavelengths of light emitted. The term “LED” also encompasses devices having either an individual light-emitting p-n junction or an array of p-n junctions. The preferred embodiment includes a total of ten (10 ea.) LEDs60,61,62,63,64,65,66,67,68and69, pairs of which are mounted on respective circuit boards71,73,75,77and79. Each LED60-69in the preferred embodiment is a device which actually includes four (4 ea.) individual LED dies mounted under a common dome-shaped optic60a,61a,62a,63a,64a,65a,66a,67a,68aand69awhich projects light in a pattern surrounding a respective optical axis60b,61b,62b,63b,64b,65b,66b,67b,68band69b. Each of LEDs60-69are mounted supportably to, and are thermally conductively coupled to, respective ones of the facets55-59of body40by way of a thermal path90-99of low thermal resistance and high heat carrying capacity. The thermal paths92and93which thermally conductively link body40with LEDs62and63, respectively are schematically represented by broken arrows in the partially exploded view ofFIG. 5. While it is to be understood that corresponding thermal paths90,91and99exist between body40and LEDs60,61and64-99, respectively, for clarity of illustration only thermal paths92and93are called out in the drawings, and, since thermal paths90-99are alike in all relevant respects in the preferred embodiment, the description will proceed with reference only to thermal path92which is typical of its counterparts.

Thermal path92begins with LED62itself. Although at least a portion of LED62could if desired be supportably mounted to body40by mating in face-to-face contact with the facet52of body40, such facial contact is neither required by the invention nor is it preferred. In the preferred embodiment, LED62is supportably mounted to facet52and thermally conductively coupled thereto by way of one or more interposed substrates, in this case, circuit board73, which has an electrically conductive path103to which LED62is electrically and mechanically connected by wave soldering or alternative surface mount technology (SMT) as commonly employed for mounting electronic components on circuit boards in the electronics industry. As can be clearly seen fromFIG. 5, circuit board73includes at least one, and preferably a plurality of electrically conductive paths103which are used to conduct electrical energy to LEDs62and63to enable them to emit a desired amount of light for a particular application. Analogous electrically conductive paths101,105,107and109are carried by circuit boards71,75,77and79, respectively for conducting electrical energy to LEDs60and61,64and65,66and67and68and69, respectively. In the preferred embodiment, electrically conductive paths101,103,105,107and109each include four (4 ea.) separate circuit traces, one of which is connected to each respective one of the four (4 ea.) individual p-n junction dies associated with each of LEDs60-69so that all or any desired subcombination of those p-n junctions can be selectively energized or de-energized thus providing a high degree of control over both the intensity and pattern of illumination provided by module10. Circuit boards71,73,75,77and79may be mechanically and thermally conductively coupled to their respective facets55-59either in direct face-to-face contact or indirectly by way of one or more thin layers (not shown) of electrically insulating but thermally conductive material such as mica and/or one or more layers (not shown) of thermally conductive paste of the type described above. Circuit boards71,73,75,77and/or79may also have mounted thereon, all or part of an LED driver circuit85for supplying sufficient electrical energy to one or more of the LEDs60-69to enable them to emit a desired amount of light for a particular application. Circuit boards71,73,75,77and79are mechanically coupled to body40by cap screws114as shown inFIG. 5.

The module10of the preferred embodiment illustrated inFIGS. 1-5is ideal for providing a Type V distribution pattern when LEDs60-69are all fully illuminated since, as illustrated inFIG. 3, module10can be bisected by an imaginary vertical plane82one side of which,82A, will be illuminated mainly by a total of six LED's, namely LEDs66,67,68,69,60and61mounted on three facets, namely facets57,56and55. The opposite side,82B, of plane82will be illuminated mainly by a total of only four LED's, namely LEDs62,63,64, and66mounted on two facets, namely facets57,56and55and therefore will receive less illumination, even when all of LED's60-69operate at full light output. Such an overall lighting distribution pattern is ideal for example for post-lights mounted between a street and sidewalk where it is frequently desirable to cast more light into the street than in the opposed direction toward the sidewalk which may adjoin a residential property. This can easily be achieved by elevated mounting of module10on a lamppost located beside the street in an orientation such that plane82is oriented generally parallel to the street with side82A facing the street and side82B facing the sidewalk beside the street. Those skilled in the art will immediately appreciate that by allowing for variation of the number of facets included in polygonal array52, the value of the downward angles124of the facets, the number and spacing of LEDs on particular ones of the facets, the angular values of the acute angles125at which the respective optical axes of respective ones of those LEDs are oriented relative to mounting axis47, the elevations of respective ones of those LEDs relative to a reference elevation200, the invention affords great flexibility and many different lighting patterns can be provided.

In the preferred embodiment, LEDs60-69emit white light and each rated at about six point six Watts (6.6 W) at full output. The overall maximum rated electrical power consumption of module10is about sixty six watts (66 W) at one hundred twenty volts A.C. (120 VAC) and a power supply line frequency of sixty Hertz (60 Hz.). With LED's60-69electrically driven by an LED driver85such as a type LP109-36-GC-170 available from High Perfection Technology Co., Ltd of Florida module10is capable of delivering a total of 4273.9 lumens at an efficiency of 64.7 lumens per watt. Driver85may suitably comprise any one of a variety of widely commercially available LED drivers selected according to the needs of a particular application. Other suitable alternatives include without limitation a type LP1090-36-GG-170 or a type LP1090-24-GG-170, both available from Magtech Industries of Las Vegas, Nev. If desired, driver85may be mounted within an enclosed portion of a housing35of a light fixture36as illustrated inFIG. 2. Alternatively, all or a portion of driver85may be mounted on one or more of the substrates, namely circuit boards,71,73,75,77, and/or79as schematically illustrated inFIG. 3.

As illustrated inFIG. 2, module10may optionally include one or more light shields116which extend radially outwardly from one or more of the facets55-59and are positioned to prevent at least some of the light118emitted by at least one of LEDs69-69from being projected in a skyward direction so as to facilitate compliance with so-called “dark sky” regulations or standards which seek to limit skyward light emissions. For enhanced energy efficiency, light shields116are preferably provided with a specular reflective surface121which re-directs light117in a downward direction schematically illustrated by arrow122where it contributes to the level of useful illumination delivered by module10. Light shields116could be of any suitable material such as a plastic provided with a metallized reflective surface121but are preferably fabricated as extrusions or formed from sheets of highly thermally conductive material so they may serve as heat, dissipating members which are thermally conductively coupled to polyhedral body40and thus help conduct heat away from body40and liberate it to the adjoining environment. In the preferred embodiment, light shields116are formed from sheets of aluminum and have highly polished anodized surfaces and are secured to body using pressure-sensitive adhesive strips123.

As shown inFIG. 2with reference to facet56and LED63as a typical example, each facet55-59is oriented at a downward angle124with respect to mounting axis47and faces outwardly away from mounting axis47. The optical axis60b-69bof each respective LED60-69is oriented at an acute angle125with respect to mounting axis47. In the preferred embodiment, the downward angle124is preferably an angle within a range of about twenty five degrees (25°) to about thirty degrees and is most preferably about twenty nine point seven degrees (29.7°). While the downward angle124happens to be of the same for each of facets55-59, such an arrangement is not essential to the invention. Any or all of facets55-59may be oriented with respect to mounting axis47at a downward angle124of an angular value which differs from the angular value of the downward angle124of the one or more of the other facets55-59without departing from the scope of the invention. Likewise, the acute angles125of optical axes60b-69bwith respect to mounting axis47can be, but need not necessarily be, of the same angular value for each one of LEDs60-69instance. In the preferred embodiment each acute angle125is preferably within a range of about sixty five degrees (65°) to about sixty degrees (60°) and is most preferably about sixty point three degrees (60.3°). In the preferred embodiment, downward angle124and acute angle125are complimentary angles meaning that when added together, their respective angular values total ninety degrees (90°).

Each circuit board71,73,75,77and79in the preferred embodiment has mounted thereon at least one (1 ea.) first mating part127aof at least one electrical connector127of the type which includes a first mating part127aand a second mating part127bwhich are selectively disconnectably coupleable to one another, both electrically and mechanically. Each second mating part127bis electrically coupled to one or more electrically conductive traces (not shown) on the respective one of circuit boards71,73,75,77,79to which that mating part127bis mounted for carrying control signals and/or electrical power to one or more of LEDs60-69. Electrically connections between adjacent ones of circuit boards71,73,75,77and79are made by way of ribbon cables129having multiple electrical conductors which terminate at respective individual poles of pairs of second mating parts127b. For clarity of illustration, only one pair of second mating parts127band only one ribbon cable129are shown in the drawings.

As illustrated inFIG. 3, body40includes a second passage131which, in cooperation with first passage32serves as a conduit for routing electrical conductors33,34internally through body40for mechanical protection and concealment. Second passage131has a generally radially oriented longitudinal axis which runs generally transverse to mounting axis47and first passage32. Second passage131communicates with first passage32by way of a first end132which opens into first passage32and has a second end133which opens at the exterior surface of body40at a location where facets56and57intersect. Electrically conductors33,34terminate with a second mating part127bof the detachable connector127whose first mating part127ais mounted to circuit board77.

According to a second preferred embodiment as illustrated inFIGS. 6 through 9, module10also include an active cooling device136for enhancing the removal of heat from fins49by inducing active airflow in the vicinity of fins49. While active cooling device136may suitably take the form of a motor-driven impeller, an active cooling module of the type readily commercially available from Nuventix, Inc. of Austin, Tex. under the brand name SynJet® is preferred. Active cooling device136is mounted in a cavity138formed among fins49at the top portion of module10and includes an electrically driven actuator (not shown) which creates turbulent, high-momentum air-jets which are expelled from nozzles139. Each pulse of air creates a turbulent wake that pulls in ambient air behind it and enhances small-scale mixing and thermal transfer at the boundary layer near the heated surfaces of fins49thus providing high heat transfer at low-volume flow rates.

A third preferred embodiment of an LED lighting module10according to the invention is illustrated inFIGS. 10 and 11. As an option, the embodiment ofFIGS. 10 and 11includes an active cooling device136with nozzles139as described above which is mounted in a cavity138formed among the heat-dissipating fins49which are mechanically and thermally conductively coupled to polyhedral body40. Unlike the embodiments ofFIGS. 1-9, the embodiment ofFIGS. 10 and 11does not include a support post12. Instead, module10is adapted to be suspended in an installed position from a light fixture36. In the embodiment ofFIGS. 10 and 11, this is achieved through use of an inverted “U”-shaped mounting bracket which is secured to fixture36by screws, rivets or any other suitable fastener146and is secured to polyhedral body40by cap screws148which penetrate mounting bracket144and are received in threaded holes150formed in body40.

In addition to the LEDs60-69mounted on facets55-59, the polyhedral body40of the embodiment ofFIGS. 10 and 11includes at least one additional LED, and more preferably, two additional LEDs153,154which are mounted to a lower surface155of body40by way of a sixth circuit board156.

FIG. 12shows preferred embodiment of a luminaire158which incorporates an LED lighting module10of the type shown inFIGS. 1-5and described in detail above with reference thereto. Module10is mechanically coupleable to the housing35of luminaire158by a nut39and washer38in the manner described above with reference toFIG. 2. Housing35is supported a height above ground level by a lamppost160. In the preferred embodiment, the height of lamppost160is such that LEDs60-69are positioned at a height of about three meters (3 m) above ground level but it is to be understood that the height of the module10above ground level will vary to accommodate the needs of a particular application. Module10is mounted to housing35so that the mounting axis47of module10is oriented substantially vertically. If desired, a luminaire158constructed as otherwise shown inFIG. 12may optionally be provided with an active cooling device136mounted at least partially within a recess138formed among fins138. As a further option, one or more of the light shields116may be omitted if desired.

Shown partially cut away inFIG. 12, luminaire158includes a lens162which is transparent or at least partially translucent and is mechanically coupleable to housing35in any conventional manner. Lens162encloses an interior cavity165inside of which is located all of module10except the threaded lower end15of support12. The heat exchanging fins49of body40and the heat exchanging fins28carried by support12are all directly exposed to the ambient environment inside interior cavity165which may or may not be at least partially vented by one or more openings in lens162itself and/or housing35so as to be capable of at least some air circulation between interior cavity165and one or more other areas such as the external ambient environment167outside luminaire158and/or spaces inside housing35.

Lens162may be of any transparent or translucent material suitable for allowing at least a portion of the light energy118emitted from one or more LEDs60-69to pass through the lens162for illuminating an area located exteriorly of lens162. Lens162can be of any of a diverse variety of materials including but not limited to a tempered or non-tempered glass, laminated or non-laminated resins or thermoplastics such as polycarbonate, polystyrene or acrylic. Lens162may also be of a composite of any two or more such materials, such as one having one or more layers of plastic captured between one or more layers of glass to impart resistance to shattering. For high temperature applications, or applications where lens162may be subjected to sudden extreme temperature changes, such as those that might occur if a lens162already hot from operation and/or sun exposure is suddenly sprayed with rain or a cleaning solution, a material having a low coefficient of thermal expansion can be used to avoid shattering of lens162due to thermal stress. Such materials include borosilicate materials such as those readily commercially available from a number of sources including for example Corning 7740 glass and others available from Corning Inc under the brand name Pyrex® and Schott Glass 8830 glass and others available from Schott Glass under the brand name Duran®.

Lens162may be formed using any of a variety of processes, the selection of which will depend primarily on the selection of its material and particular final shape and mechanical and optical properties desired. Glass materials are typically formed into shape by molding or casting. Thermoplastics can be processed into a desired shape in any of a variety of ways including processes such as injection molding, extrusion vacuum forming and machining. Lens162can also be formed by flowing a hardenable liquid material such as a mixture including a resin and a catalyst into a mold.

If desired, all or any part(s) of lens162can be colored or otherwise treated to alter the wavelength or other optical characteristics of the light emitted from module10. This can be achieved for example by fabricating lens162from a colored material, or by adding a coloring agent to the base material from which lens162is to be cast or molded. It is also an option to provide the interior and/or exterior surface of lens162with a coating or an applied film layer which could either be clear, colored and/or if desired, have special optical characteristics. For example, such a layer or coating could optionally comprise a polarizing filter or a non-polarizing filter. In the preferred embodiment however, lens162is substantially clear and uncolored. It is also to be appreciated that lens162may optionally be etched, “frosted” or provided with any other desired surface finish or texture. Such surface finish or texture can be formed during a molding or casting process by fabricating a surface to include a surface finish or texture that is imparted directly to the lens. Alternatively, such a texture or finish can be provided by carrying out a secondary operation on all or part of an interior or exterior surface of lens162, such as blasting a surface of lens162with an abrasive media, or applying a chemical etching agent to that surface, or applying a coating to the surface. Glass surfaces for example can be surface etched by applying certain acids.

Lens162may, if desired, be shaped or otherwise adapted to refract focus, or defocus or change the direction of the light44emitted from one or more of LEDs60-69in a particular manner and/or to alter its wavelength or other optical characteristics. However, it is to be understood that the term “lens” as used herein and in the claims can be, but is not limited to a structure capable of focusing, defocusing and/or changing the direction, wavelength, polarization or other characteristics of light, or a structure that has an axis of symmetry or has optical characteristics beyond an ability to allow at least some of the light from at least one of LEDs60-69to pass through at least a portion of lens162itself so it can illuminate an area external to lens162.

FIGS. 13 and 14illustrate a preferred embodiment of a luminaire170which incorporates an LED lighting module10of the type shown inFIGS. 9 and 10and described in detail above with reference thereto. Luminaire170includes an LED lighting module10having a polyhedral body40having a plurality of facets55-59arranged in a polyhedral array52. Supportably mounted on facets55-59are respective pairs of LEDs60-69which are thermally conductively coupled to body40by way of respective circuit boards71,73,75,77and79. LEDs60-69each have respective optical axes60b-69bwhich are oriented at an acute angle125with respect to mounting axis47. An additional pair of LEDs153and154with respective optical axes153band154bare mechanically and thermally conductively coupled to a lower surface155of body40by way of a circuit board156. Optical axes153band154bare preferably oriented parallel to mounting axis47or at an acute angle172whose angular value is less than the angular value of acute angle125. In the preferred embodiment one or both optical axes153b,154bare parallel to or co-linear with mounting axis47, so that the angular value of angle172is substantially zero degrees. A plurality of mutually spaced heat dissipating fins49are supportably mounted to and are thermally conductively coupled to body40. Preferably, body40and fins49are formed integrally with one another and are fabricated by machining from a monolithic piece of highly thermally conductive stock or are formed together as a one-piece casting.

The embodiment ofFIG. 13optionally includes an active cooling device136mounted in a recess formed among fins49. although a fan, a thermo-electric module or the like could optionally be used, active cooling device136is preferably of the type described above which emits a succession of turbulent air jets from nozzles which are directed at or between fins49to enhance the transfer of heat away from fins49and thus, body40.

As illustrated inFIG. 13, body40is supported in an installed position relative to the housing35of luminaire170with the aid of a mounting bracket144which suspends module10inside housing35′. Bracket144is mechanically coupled to body40by cap screws148and is connected by fasteners146, such as rivets, to a support member175which is in turn secured by rivets or other fasteners176to a baffle179. In the preferred embodiment, baffle179is formed of sheet metal and is shaped generally in the form of a truncated cone which widens progressively from its top to a peripheral rim181by way of which baffle179is mechanically coupled to the housing35′ of luminaire170. As an option, lens162′ may be secured to housing35′ to enclose module10within housing35′. As illustrated inFIG. 14, luminaire170may also optionally include a reflector184such as one of a parabolic shape, interposed between module10and baffle179as shown. In lieu of a reflector184, luminaire170may be provided with one or more light shields116, each having a reflective surface121as described in connection withFIGS. 1-5above.

FIG. 15is a diagram which illustrates the proper elevational positioning of LEDs60-69with respect to an elevation reference level200of a light fixture or luminaire in which an LED illumination module10is to be mounted. Elevation reference level200may be the elevation of any point or locus of points whose elevation with respect to the housing35or35′ of the light fixture36, luminaire158or luminaire170remains substantially fixed after the light fixture36or luminaire158or170has been installed. By way of non-limiting example, an arbitrary elevation reference level200corresponding to the top surface of the housing35of the fixture36inFIG. 2and the luminaire158inFIG. 12and the uppermost inside surface204of the baffle179of luminaire170inFIG. 13.

According to the invention, the proper elevational distance, E, between at least some, and preferably all, of the LEDs60-69mounted to the downwardly angled and outwardly facing facets55-59is determined in relation to the installed elevation and orientation of the lamp or lamps which were originally present in the fixture or luminaire or for which the fixture or luminaire was originally designed to operate. Such lamp or lamps is referred to hereinafter and in the claims as the “replaced lamp” and is designated inFIG. 15by reference numeral203. Typically a replaced lamp203has a base205and an envelope210having a major dimension215. Typically, the envelope of a replaced lamp will be of glass, quartz or other transparent or at least partially translucent crystalline material. The term “replaced lamp” is to be broadly construed to encompass any and all types of electrically powered lamps regardless of the physical process or processes by which they generate light and includes without limitation incandescent lamps, fluorescent lamps, gas discharge lamps and other types whether presently known or invented in the future. The term “replaced lamp” is also not to be limited by the shape or configuration of the replaced lamp203shown inFIG. 15. It is to be understood that such illustration is of a schematic nature and is only intended as an example and not a limitation.

The elevational positioning of at least some of LEDs60-69in applications in which module10is to be used to replace, or used in lieu of, a replace lamp203awhose installed position is in a base-up orientation as illustrated in the left most example inFIG. 15. The body40of module10is to be supported in an installed position by support12, or by mounting bracket144, such that the elevational centers of at least some of LEDs60-69are positioned at an elevation, E, lying within a range220that is centered at the midpoint of the major dimension215of the envelope210of the replaced lamp203ain its installed position as shown. Range220extends over not more than twenty five percent (25%) of the major dimension215of the replaced lamp203a. In the case of a replaced lamp such as a straight fluorescent tube having a straight tubular envelope with a “base” at opposite ends thereof, module10should be elevationally positioned by treating it as a “base-up” oriented replaced lamp203aif the central axis of the fluorescent tube in its installed position is vertical or within about sixty degrees (60°) of vertical. In such applications, module10should be elevationally positioned as just described. However, if in its installed position the angle of the tube exceeds sixty degrees (60°) from vertical, that is, if the tube is mounted with its major axis oriented horizontally or within about thirty degrees (30°) of horizontal, the module10should be elevationally positioned as for replacing a horizontally mounted replaced lamp203c.

In applications where module10is to be used to replace, or used in lieu of, a base-down oriented replaced lamp203b, the body40of module10is to be supported in an installed position by support12or bracket144such that the centers of at least some, and preferably all, of LEDs60-69are oriented at an elevation, E, which substantially corresponds to the elevation of the top of the replaced lamp203bin its installed position in the light fixture35, luminaire158or luminaire170. Alternatively, the body40of module10may be supported by support12or mounting bracket144in an installed position such that at least some, and preferably all, of LEDs60-69are elevationally centered at an elevation, E, which lies within a range225which extends from about the elevation227of the top of the replaced lamp203bin its installed position to a lower elevation229. Lower elevation229is an elevation whose distance from the elevation227of the top of replaced lamp203bin its installed position is not more than twenty five percent (25%) of the major dimension215of the envelope210of replaced lamp203b.

In the case of a replaced lamp203cmounted such that the central axis of envelope210is mounted substantially horizontally, within plus or minus fifteen degrees (15°) of horizontal support12or bracket114positions, body40relative to fixture36, luminaire158, or luminaire170such that the installed position of module10is a position at which the centers of at least some, and preferably all, of LEDs60-69are at an elevation, E, which substantially corresponds to the central axis230of replaced lamp203c.

From the foregoing, it will be appreciated that because substrate39is thermally conductively coupled to, and located substantially immediately adjacent proximity to, LED37on its one side, and first heat sink47on it its opposite side, LED37and first heat sink47are themselves thermally conductively coupled to one another and are located substantially immediately adjacent to one another.

If module10is to be used in a retrofit application in place of a replaced lamp203, the operating position and orientation of the base205of the replaced lamp203are noted prior to removal of the replaced lamp203from the light fixture36or luminaire, such as a luminaire158or170, in which module10is to be installed. The elevational distance from the top of the envelope210of the replaced lamp203to a reference level200of the housing35of the fixture36or luminaire158or170is measured and recorded. Also measured and recorded are the major dimension215of the envelope210of the replaced lamp203and the elevation of its midpoint218in relation to the aforementioned midpoint200. After removal of the replaced lamp203module10is installed to the housing35of the fixture36or luminaire158or the housing35′ of luminaire170. In the case of a module10according to any of the embodiments ofFIGS. 1 through 12, module10is installed in an operating position by passing the threaded lower end39of support12through a suitable opening37in the housing35and securing it in place using a nut39and washer38as illustrated inFIG. 2. After driver circuit85is connected to a suitable source of AC electrical power (not shown) two or more electrical conductors33,34for supplying electrical energy to LEDs60-69are routed internally through support12by way of first passage32and internally through polyhedral body40by way of second passage131. Electrical conductors33,34emerge from the second end133of passage131where they terminate in a second mating part127bwhich is disconnectably mechanically and electrically coupled to the first mating part127aof at least one of the electrical connectors127which are in turn electrically coupled to one or more of the electrically conductive paths101,103,105,107, and109of circuit boards71,73,75,77and79, respectively.

After one or more of LEDs60-69, and in the case on the embodiments ofFIGS. 10 through 14also LED's153and154, are initially energized by driver circuit85by way of electrical conductors33and34, the energized ones of those LEDs begin to LED emit light118as well as generate a substantial amount of heat. The temperatures of the energized ones of LEDs60-69,153and154begin to rise rapidly but a large fraction of that heat is rapidly transported by thermal conduction from the LED's into highly thermally conductive polyhedral body40by way of one or more of thermal paths90-99which, as noted above in the preferred embodiments include respective ones of circuit boards71,73,75,77and79. Some of the heat entering polyhedral body40begins to be drained away from polyhedral body40by thermal conduction to the heat dissipating fins49which extend from body40itself, as well by way of the heat dissipating fins28extending from support12. In turn, heat dissipating fins28and49liberate heat away from themselves by way of radiation and convection to adjacent air. Some heat is also liberated from body40by radiation emanating directly from body for zero itself.

During the thermal lag period which occurs before heat can begin to be drained away from body40at a rate at least as rapid as that at which heat is entering body40, the body40has sufficient thermal mass and is coupled to LEDs60-69,153and154by way of sufficiently low thermal resistance that body is able to take on heat from the energized ones of LEDs60-69,153and154at a sufficiently rapid rate of heat flow to prevent any of LEDs60-69,153and154from exceeding a temperature limit such as a maximum operating temperature at a particular location such as one which may be specified by the manufacturer of the LEDs. At the end of the thermal lag period, the duration of which will depend on local ambient conditions as well as the particular structure and materials of a particular embodiment, the rate at which heat is liberated from polyhedral body40will at least equal the rate at which polyhedral body for40takes on heat from the energized LEDs. While one or more LED's need not be supportably mounted to every one of downwardly angled facets55-59of polyhedral body40, at least one LED is supportively mounted to each of at least a majority of the total number of such facets present in a particular embodiment thereby providing significant arcuate spreading of the illumination over the area to be illuminated while allowing flexibility to provide lower or substantially no illumination to selected arcuate regions surrounding the mounting axis of module10.