US007883243B2
`
`United States Patent
`(12)
`(10) Patent No.:
`US 7,883,243 B2
`Snyder
`(45) Date of Patent:
`Feb. 8, 2011
`
`
`(54) LED FLASHLIGHT AND HEAT SINK
`ARRANGEMENT
`Inventor: Mark W. Snyder, Hockessin, DE (US)
`
`(75)
`
`(73) Assignee: Streamlight, Inc., Eagleville, PA (US)
`
`(*) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`US.C. 154(b) by 565 days.
`
`(21) Appl. No.: 11/779,038
`
`(22) Filed:
`
`Jul. 17, 2007
`
`co
`
`5,463,541 A
`5,486,432 A
`5,567,036 A
`5,678,921 A
`5,785,418 A
`5,806,965 A *
`5.821.695 A
`ont
`5,871,272 A
`6,585,391 B1L*
`6,633,152 B2
`
`10/1995 Greene
`‘1/1996 Sharrah et al.
`10/1996 Theobald etal. 362/485
`10/1997 Kish et al.
`7/1998 Hochstein
`9/1998 Deese ...... eee 362/249.04
`10/1998 Vilanilam et al
`‘
`2/1999 Sharrah et al.
`7/2003 Kochetal. we 362/205
`10/2003 Sharrah et al.
`
`(65)
`
`Prior Publication Data
`US 2008/0018256 Al
`Jan. 24, 2008
`
`(Continued)
`OTHER PUBLICATIONS
`
`(51)
`
`Streamlight, Inc., “Introducing the New Survivor from Streamlight”,
`http:/Avwwstreamlight.com/survivor_info.htm, printed Jun. 22,
`2006, I page
`
`(Continued)
`Primary Examiner—Thomas M Sember
`(74) Attorney, Agent, or Firm—Clement A. Berard, Esq.;
`Dann, Dorfman, Herrell & Skillman, P.C.
`
`(57)
`
`ABSTRACT
`
`Related U.S. Application Data
`(60) Provisional application No. 60/832,106,filed on Jul.
`20, 2006.
`Int. Cl.
`(2006.01)
`F21L 4/00
`(2006.01)
`F21V 29/00
`(52) U.S. Ch wee 362/294; 362/196; 362/200;
`362/373
`(58) Field of Classification Search................. 362/294,
`362/373, 545, 547, 202-208, 646, 631, 249.02,
`362/218, 345, 196, 200
`
`See applicationfile for complete searchhistory. AnLEDlight may comprisealight emitting diode selectively
`References Cited
`(56)
`energizable for producing light; an electronic circuit for
`selectively energizing the light emitting diode; and a heat sink
`U.S. PATENT DOCUMENTS
`ofa thermally conductive material, whereinthe light emitting
`4313272 A
`2/1982 Matthews
`diode is thermally bondedto the heat sink; and wherein the
`4,531,178 A
`71985 Uke
`electronic circuit is attached to the heat sink. The light may
`4,683,523 A
`7/1987 Olssonetal.
`havea pair ofcontact springs extending fromthe heat sink and
`4,729,076 A
`3/1988 Masamiet al.
`the electronic circuit may include thermal conductivity
`4,885,668 A
`12/1989 Maglica etal.
`enhancing features.
`5,309,337 A
`5/1994 Groben
`5,404,281 A
`4/1995 Parker
`5,432,689 A
`7/1995 Sharrah et al.
`
`68 Claims, 5 Drawing Sheets
`
`
`
`Parhelion, Inc.
`EXHIBIT
`
`1008
`
`0000336
`
`

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`US 7,883,243 B2
` Page 2
`
`U.S. PATENT DOCUMENTS
`
`8/2005 Chen ......eee 362/241
`2005/0168985 Al*
`9/2005 Cassarly et al.
`2005/0201100 Al
`11/2005 Van Duyn
`2005/0243558 Al
`11/2004 Cassarly et al.
`6,819,505 B1
`1/2006 Coushaineetal.
`2006/0013000 Al
`12/2004 Galli
`6,827,468 B2
`2/2006 Maglicaet al.
`2006/0039139 Al
`9/2005. Galli
`6,942,365 B2
`3/2006 Kumthampinij et al.
`2006/0067077 Al
`11/2005 Galli
`6,966,677 B2
`5/2006 Martin
`2006/0109655 Al
`12/2005 Galli
`6,974,234 B2
`
`7,008,084 B2=3/2006 Galli 2006/0109661 Al* 5/2006 Coushaineet al. ........4. 362/373
`
`7,014,335 B2
`3/2006 Probstet al.
`2006/0145180 Al
`7/2006 Galli
`7,055,989 B2
`6/2006 Galli
`2007/0253194 Al
`11/2007 Sharrah et al.
`7,083,305 B2
`8/2006 Galli
`7,220,013 B2
`5/2007 Sharrah etal.
`2004/0054386 Al
`3/2004 Martin etal.
`2005/0017366 Al
`1/2005 Galli
`2005/0024864 Al
`2/2005 Galli
`2005/0057187 Al
`3/2005 Catalano
`2005/0083686 Al
`4/2005 Yatsudaetal.
`2005/0122713 Al
`6/2005 Hutchins
`2005/0128741 Al
`6/2005 Matthews et al.
`2005/0161684 Al
`7/2005 Galli
`2005/0161692 Al
`7/2005 Galli
`
`Streamlight, Inc., “Survivor Specifications”, http://www.streamlight.
`com/survivor_specifications.htm printed Jun. 22, 2006, 2 pages.
`Streamlight,
`Inc., “Survivor Parts & Accessories”, http://www.
`streamlight.com/survivorlight.com/survivor_accessories_2001.
`htm printed Jun. 22, 2006, 1 page.
`Streamlight, Inc., “Syclone Assembly C130000A”, 1999, 1 page.
`
`
`
`OTHER PUBLICATIONS
`
`* cited by examiner
`
`0000337
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`

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`U.S. Patent
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`Feb. 8, 2011
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`US 7,883,243 B2
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`U.S. Patent
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`U.S. Patent
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`U.S. Patent
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`[--------------------—-—--------------------
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`crve0000
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`

`

`1
`LED FLASHLIGHT AND HEAT SINK
`ARRANGEMENT
`
`2
`be attached to the second generally rectangular planar mem-
`ber betweenthe two opposing elongated members.
`
`US 7,883,243 B2
`
`BRIEF DESCRIPTION OF THE DRAWING
`
`This Application claims the benefit of U.S. Provisional
`PatentApplication No. 60/832, 106 filed Jul. 20, 2006, each of
`The detailed description of the preferred embodiment(s)
`which is hereby incorporated herein by reference in its
`will be more easily and better understood when read in con-
`entirety.
`junction with the FIGURESof the Drawing which include:
`Thepresent inventionrelatesto a light and, in particular, to
`FIG. 1 is a view of an example embodimentof a light
`a light having a light emitting diode anda heatsink.
`including the present arrangement;
`Increasingly,
`flashlights and other portable lights are
`FIG. 2 is an isometric view ofa first side of an example
`employingasolid state light source, such as a light-emitting
`embodimentofa light accordingto the present arrangement;
`diode (LED), particularly as the brightness of the available
`FIG.3 is an isometric view ofa second sideofthe example
`LEDshasimproved and as LEDs have becomeavailable that
`embodimentofa light according to FIGS.1 and 2;
`producebright “white” light.
`FIG.4 is an exploded isometric view of the heat sink and
`LEDassembly ofthe example embodimentofa light accord-
`Unlike incandescent lamps which depend uponthe heating
`ing to FIGS. 1-3;
`ofalight producingfilament to a high temperature to produce
`FIGS. 4A and4Bare plan viewsof alternative example
`light, LEDsare desirably operated at lower temperaturesat
`embodiments ofa circuit board of an example LED assembly
`whichtheir efficiency andreliability is better. Thus, whereas
`as shown in FIGS.2 and 4; and
`it wasrelatively unimportant in manyinstances to remove the
`FIG. 5 is a schematic diagram of an example electronic
`heat generated by an incandescent lamp,
`it may be quite
`circuit useful with the light of FIGS. 1-4.
`important that heat generated by a high-power LED be
`removed.
`In the Drawing, where an element or feature is shown in
`morethan one drawingfigure, the same alphanumeric desig-
`While incandescent lamps maybesatisfactorily operated
`nation may beused to designate such element or feature in
`by applying a voltage, e.g., a battery voltage, directly to the
`each figure, and whereaclosely related or modified element
`lamp, such is not a desirable way in whichto operate a solid
`is shown in a figure, the same alphanumerical designation
`state light sourcesuch as an LED. Thus, along with the use of
`primedor designated “a”or “b”or the like may be used to
`LEDsaslight sourcesin portable lights has cometheutiliza-
`designate the modified element or feature. It is noted that,
`tion of electronic circuits for conditioning the electrical
`according to commonpractice, the various features of the
`powerprovided by an electrical power source into a form
`drawingare notto scale, and the dimensionsof the various
`moresuitable for the LED, for example, for controlling the
`features are arbitrarily expanded or reducedfor clarity, and
`level of current flowing through the LED.
`any value stated in any Figure is given by way of example
`5 only.
`As such powerregulating circuit technology has been
`developed, power regulating circuits have also come to be
`employed with incandescent light sources as well as with
`solid state light sources. As a result, portablelights have come
`to include electronic circuitry as well as the usual battery (or
`batteries) and light sources.
`Because heat can be detrimental to electronic circuitry,
`there is a need to removeheat from such circuitry. In addition,
`certain failure and/or fault conditions may cause additional
`heat to be produced that could raise the temperature of elec-
`tronic circuitry to a temperaturethat is not only detrimental to
`the circuitry, but that could also be a hazard or a danger to the
`circuitry or otherwise.
`Accordingly, there is a need for light including a heat sink
`arrangement for removing heat from a light source and/or
`electronic circuitry ofthe light.
`To this end, a light may comprise a light emitting diode
`selectively energizable for producinglight; an electronic cir-
`cuit for selectively energizing the light emitting diode; and a
`heat sink ofa thermally conductive material, wherein the light
`emitting diode is thermally bonded to the heat sink; and
`wherein the electronic circuit is attached to the heat sink.
`
`10
`
`20
`
`40
`
`aswa
`
`wnOn
`
`Accordingto anotheraspect, a light may comprise a heat
`sink includinga first generally rectangular planar member,
`two opposing elongated members each integrally joined to
`the first rectangular planar member, and a second generally
`rectangular memberintegrally joined to the two elongated
`members andto the first generally rectangular member. A
`light emitting diode may be attachedto the first generally
`rectangular planar memberbetween the two elongated mem-
`bers and circuitry for energizingthe light emitting diode may
`
`60
`
`0000343
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT(S)
`
`FIG. 1 is a view of an example embodimentofa light 10
`including the present arrangement. Light 10 includes a hous-
`ing 20 includinga portion 30 in which a battery or batteries
`maybe providedanda portion 40 in whichare a reflector 42
`andlight 10' and a sourceofelectrical power such as a battery
`40. Housingportion 40 maybe angled with respect to housing
`portion 30,e.g., approximately perpendicularly asillustrated,
`or at anotherangle, or housingportions 30, 40 maybeaxially
`aligned, as may bedesired. In the illustrated arrangement,
`light 10 may desirably be placed with base 32 on a generally
`horizontal surface or into a charger unit and remain standing
`thereon with light produced by light 10' emanating outwardly
`in a generally horizontal direction.
`A light 10' (notvisible, described below) may be disposed
`at the base ofreflector 42 internal to housing 20 substantially
`at the intersection ofthe rear oflight housing 40 and the upper
`end ofbattery housing 30, thereby to project a beam oflight
`from reflector 40 through lens 44. Within housing 20oflight
`10 is a heat sink 100 (not visible, described below) which
`generally conformsto the geometry and shapeof housing 20
`and which dissipates heat generated by light 10' therein and
`which supports the light source and electronic control cir-
`cuitry therefor.
`Battery housing portion 30 may includeat its base 32 an
`access cover 36 that has hinges and/orclasps34 forattaching
`cover36 to battery housing portion 30 and through which the
`battery or battery may be inserted and removed, and may
`optionally include contacts for making electrical connection
`
`

`

`US 7,883,243 B2
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`_ wn
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`30
`
`4
`A
`reach or exceed a temperature whichis considered by Under-
`with a charger unit into which light 10 may be placed for
`writers’ Laboratory (UL)to be dangerously hot, thereby to be
`chargingthe battery in housing portion 30.
`eligible for UL approvalof light 10, 10' as a ClassI, Division
`Light source housing portion 40 may include a ring mem-
`I, device. For UL approvalfor use in an environmentsubject
`ber that removably attaches to housing portion 40, e.g., in a
`to T4 gases, the maximum allowable component temperature
`threaded engagement therewith,for retaining reflector 42 and
`for UL approval is 200° C. when the light is in a 40° C.
`lens 44 in housing portion 40. Ring member 46 could be
`ambient temperature environment. In addition,heat sink 100
`rotatable for manipulating a mechanism for adjusting the
`also serves the functions of supporting LED 210, ofposition-
`shape and/orfocus of the beam oflight produced by light 10
`ing LED 210 to be aligned with reflector 30 oflight 10, and of
`and projected outwardly through lens 34.
`supporting electronic circuit board 300 that controls the
`Housing 20 mayalso includea clip 50, e.g., secured at the
`operation of LED 210.
`rear ofhousing 20 by screws 54 engaginghousing 20 and heat
`Heatsink 100 includesa first generally rectangular mem-
`sink 100 therein, as described below. Optionally, clip 50 may
`ber 110 that is generally planar and that has front and back
`bepivoted, e.g., on pivot pin §8, and end 56 of clip 50 may be
`broad surfaces. Heat sink 100 may include two elongated
`biased against housing 20 by a spring 52 andso the end 56 of
`members 130 that are integrallyjoined to opposing edges,
`clip 50 may be moved toward and away from housing 20,
`e.g., side edges, offirst generally rectangular member 110,
`therebyto facilitate clipping light 10 to a pocket, belt or other
`and each opposing elongated member 130 typically has
`item, as may be convenient and/or desirable. Clip 50 may
`opposing ends 132, 134 that extend beyond the top and bot-
`have an optional projection extending from end 56 towards
`tom edgesoffirst generally rectangular member 110.
`housing 20(asillustrated) or not.
`A second generally rectangular member 120is integrally
`Typically, battery housing portion 30 may havea race-track
`joined to one edge, e.g., the top edge, of first generally rect-
`or oval shaped cross-section, e.g. for receiving four sizeAA
`angular member 110, and between the two elongated mem-
`battery cells in a side-by-side arrangement, and light source
`bers 130 to which its opposing ends are integrallyjoined.
`housing portion 40 maybecircular in cross-section. The four
`Typically, because ends 132, 134 of elongated members 130
`AAsize battery cells may be alkaline cells, rechargeable
`in the example embodimentextend beyond the top and bot-
`NiCd cells, or another suitable battery cell(s), and may be
`tom edges of first generally rectangular member 110 and
`utilized as cells or may be disposed in a commonpackageto
`beyond second generally rectangular member 120, and so
`be a battery pack.
`heat sink 100 may be described as having an “H”-like shape.
`Although termssuch as front, back, top, bottom, and side
`LEDassembly 200 is attached to oneofthe broad surfaces,
`may be employed in describing the example embodimentas
`e.g., the front surface, of first generally rectangular member
`illustrated by the FIGURES,the present arrangement may be
`110, and is typically bondedto a central region of the front
`utilized in any orientation, and so what is termed top or
`surface thereof by a suitable thermally conductive adhesive.
`bottom herein may or may notbe the top or bottom in utili-
`Asaresult LED 210 ofLED assembly is thermally coupled to
`zation, what is termed front or back may or maynotbe the
`front or back in utilization, and so forth.
`heat sink 100 for facilitating the removal of heat produced by
`LED 210 whenit is energized to producelight. LED assembly
`FIG.2 is an isometric view ofa first side (or front side) of
`200 includes light emitting diode (LED) 210 that may
`an example embodimentofa light 10' and FIG.3 is an iso-
`attached for convenience in assembly to an electronic circuit
`metric view of a secondside (or rear side) of the example
`board (described below) for making electrical connections
`embodimentof light 10' according to the present arrange-
`between LED 210 and electronic circuit board300, suchas by
`ment. Light 10' may comprise a heat sink 100, a light emitting
`conductors 340, e.g., insulated wires 340. Conductors 340
`diode (LED) assembly 200 attached thereto, and electronic
`circuitboards 300, 400 attached thereto.A source ofelectrical
`maybeelectrically connectedto circuit board 300 by solder-
`ing, by electrically conductive adhesive, by mechanical
`power,such as a battery, may be connected to circuit board
`crimping or swaging,or by another suitable connection.
`400 andlight 10' may be, and typically is, disposed in a case
`Electronic circuit board 300 typically carries electronic
`or housing.
`circuitry for controlling the energization of LED 210, and
`When light 10, 10' is operated under normal operating
`may comprise an electronic circuit board substrate 310 on
`conditions, certain electronic components thereof, e.g., the
`which are provided various conductors and electronic com-
`light source(e.g., LEDassembly 200) anda control device for
`ponents in conventional fashion,e.g., on either or both of the
`the light source (e.g., component 330 on circuit board 300),
`broad surfaces thereof. Examples of such electronic compo-
`typically generate heat that must be dissipated to preventthe
`nents carried on substrate 310 may include,e.g., an electrical
`temperature of such components fromincreasing excessively,
`switch 320 directly or indirectly energizing and de-energiz-
`e.g., to where such component could be damagedorfail, or to
`ing LED 210, an electronic control device 330 for applying,
`where a dangerously high temperature occurs. In normal
`removing and/or regulating or otherwise controlling electri-
`operation, the light source is typically the predominant gen-
`eratorof heat.
`cal powerapplied to LED 210, and optionally variousinte-
`In addition, underfault conditions such as the failure of an
`grated circuits, transistors, diodes, resistors, capacitors, and
`the like.
`electronic componentorashort circuit, the light source (e.g.,
`LED assembly 200) and components controlling the light
`Electronic circuit board 300 may be attached to heat sink
`source (e.g., component 330 on circuit board 300) may gen-
`100 in various ways, however, a preferred attachment
`erate more heat than under normal conditions. Under fault
`includescircuit board 300 being adjacent to second generally
`conditions, the control device often typically generates sub-
`rectangular member120,e.g., for facilitating removalofheat
`stantially greater heat than other componentsandthan it does
`from the electronic components thereon. While such heat
`under normaloperation.
`may be producedin normaloperationoflight 10', additional
`Thusheat sink 100 servesthe dual functionsof dissipating
`heat may be produced undera fault condition, e.g., damage to
`heat from thelight source 200 under normaloperation and of
`or failure of an electronic componenton circuit board 300 or
`of LED 210 orofan electrical short circuit.
`dissipating heat from other components under fault condi-
`tions. Desirably, heat sink 100 dissipates sufficient heat under
`In one such mounting arrangementfor circuit board 300, a
`both normaland fault conditions such that no componentwill
`groove 136 is provided in one elongated member 130 adja-
`
`40
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`US 7,883,243 B2
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`5
`cent second generally rectangular member 120 for supporting
`a first end of circuit board 300 and a fastener 305, such as a
`screw orbolt, supports another end ofcircuit board 300. In
`particular, it is preferred that electronic components, such as
`acontrol device 330, that may generate substantial heat under
`normal operation and/or undera fault condition be disposed
`on circuit board substrate 310 in a location that is proximate
`to fastener 305, thereby to be thermally coupled to second
`generally rectangular member120 bya relatively short ther-
`mal conduction path.
`Control device 330 maybe, e.g., a transistor that controls
`application of electrical power to LED 210, such as a MOS-
`FETtransistor, that operates as a power switching device, as
`a powercontrolling device, as a power regulating device, or
`for otherwise controlling electrical voltage or current. Circuit
`substrate 310 may include substantial electrical conductor
`area, a thicker electrical conductor, conductive vias, or
`another arrangement, proximate to the location thereon
`wherefastener 305 attachescircuit board 300 to heat sink 100
`for reducing the thermalresistance between one or more heat
`generating components, e.g., control device 330, and heat
`sink 100. While a thermally conductive grease or adhesive
`may be employedbetweencircuit board 300to heat sink 100,
`it has been foundthatfastener 305 alonetypically is sufficient
`and that such thermal greaseor adhesiveis not needed in the
`example arrangement.
`Heat sink 100 in the example embodiment preferably is
`sufficientto dissipate and/ordistribute heat generated by light
`10' under normaloperation andfault conditions without hav-
`ing an exposedsurfaceor beingattachedto a highly thermally
`conductive case or housing. Examples of fault conditions
`might include a short circuit of LED 210 or a short circuit
`directly applying full battery voltage to LED 210. Under
`normal operation and fault conditions, heat sink 100 main-
`tains LED 200, 210 andall electronic components including
`certain power handling componentson circuit board 300 to a
`safe temperature, e.g., to a temperature less than 200° C.,
`wherebylight 10, 10' is eligible for Underwriters’ Laboratory
`(UL)certification as a Division I, Class I, device and/or in a
`T4 gas environment.
`Electronic circuit board 400 includes circuit board sub-
`strate 410 that carries electrical conductors andvariouselec-
`tronic and other components in conventional fashion. Elec-
`trical contacts 420, which may be coiled spring-like
`structuresofelectrically conductive wire, extend from circuit
`board substrate 310 in a direction away from heat sink 100 for
`making electrical contact with the terminals of a battery or
`othersourceofelectrical powerfor light 10' and that may be
`carried either externally to light 10' or in a case or housing
`thereof. Electrical power from such power source may be
`carried by conductors 430,e.g., insulated wires430, connect-
`ing between electronic circuit board 400 andelectronic cir-
`cuit board 300.Conductors 430 may be electrically connected
`to circuit boards 300 and 400 by soldering, by electrically
`conductive adhesive, by mechanical crimping or swaging, or
`by another suitable connection.
`Electronic circuit board 400 is preferably attached to heat
`sink 100. For example, heat sink 100 may have a pair of
`opposing groovesor slots 130 in opposing elongated mem-
`bers 130 into which circuit board 400 is inserted. Because
`circuit board 400 in the example embodimentdoes not carry
`electronic components that would producesignificant heat
`under either normal operation or fault conditions, it is not
`necessary to provide goodthermal coupling betweencircuit
`board 400 and heat sink 100. Should such components be
`
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`carried by circuit board 400, then circuit board 400 could be
`attached to heat sink 100 is similar mannerto that employed
`for circuit board 300.
`Heatsink 100 may have oneor morefeatures for increasing
`its thermal conduction capability. For example, a raised cir-
`cular area 112 on the front surface of first generally rectan-
`gular member 110 maybeprovidedto increase the thickness
`of member 110 proximate to where LED assembly 200 is
`attachedthereto, thereby to reducethe thermalresistance and
`increasethe thermal mass ofmember 110. In addition, raised
`ridges may be provided extending from the raised circular
`area to further reduce thermalresistance and increase thermal
`mass. Tworaised substantially semi-circular features 114 on
`the rear surface of heat sink 100 have a similar benefit.
`Substantially semi-circular features 114 also provide sur-
`faces that can contactthe interior surface ofhousing 20 when
`screws 54 are tightened, and define a grooveor slot 115 which
`allows any gas that might be generated by the battery or
`batteries in housing portion 30 to flow upward to a venting
`valve(notvisible) typically located near orat the top of light
`10 proximatelight portion 40.
`Heatsink 100is typically and preferably disposed ina case
`or housing in use, and may be provided with a means for
`attaching heat sink 100 to such case or housing. For example,
`one or more holes 102 maybe provided onthe rear surface of
`heat sink 100 to receive fasteners inserted through corre-
`sponding holes in the case or housing. Holes 102 may be
`tappedor have threaded inserts to receive screwsor bolts, or
`mayreceive self-tapping orother fasteners. The fastenersthat
`engageholes 102 mayalso be utilizedto attach a part or parts
`to the outside of the case or housing, e.g., to attach a pocket
`clip, a belt clip, a spring-loaded clip, a lanyard ring, and/or
`other part.
`Heatdissipation by heat sink 100 includes conducting heat
`from the relatively small areas whereatheat is generated,e.g.,
`at LED 210 and/orat control device 330 on circuit board 300,
`to the various members ofheat sink 100, thereby to reduce
`temperature by spreadingthe heat over a substantially larger
`area and/or by allowing heat to be dissipated over that sub-
`stantially larger area.
`For example, heat generated by LED 210 onfirst generally
`rectangular member 110 is conducted dueto therelatively
`high thermal conductivity of heat sink 100 from first gener-
`ally rectangular member 110 to second generally rectangular
`member 120 and to both elongated members 130 which
`would tend to be cooler because there is no heat generating
`element thereon. Similarly, heat generated by control device
`330 on electronic circuit board 300 is conducted through
`circuit board substrate 310 and fastener 305 to second gener-
`ally rectangular member 120 is conducted dueto the rela-
`tively high thermal conductivity ofheat sink 100 from second
`generally rectangular member 120to first generally rectan-
`gular member110 andto both elongated members 130 which
`would tend to be cooler because there is no heat generating
`elementthereon.
`If and when both LED 210 and control device 330 were to
`be generating substantial heat at the same time, the heat
`therefrom is conductedto first and second generally rectan-
`gular members 110, 120 and from first and second generally
`rectangular members 110, 120 to both elongated members
`130 which would tend to be cooler because there is no heat
`generating elementthereon.
`In addition to heat conduction through heat sink 100 due to
`the relatively high thermal conductivity thereof, heat is also
`removed to a lesser extent by convection andbyradiation,
`e.g., from the elementsthat are generating substantial heatas
`well as from the surface ofheat sink 100. Further, removal of
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`0000345
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`US 7,883,243 B2
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`wn
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`First generally rectangular member 110 is seen to have a
`raised circular feature 112 on the front face thereof which
`provides a convenient flat surface on which to attach LED
`assembly 200. Becauseraised circular feature 112 increases
`the thickness of generally rectangular member 110, it also
`reducesthe thermalresistance andincreases the thermal mass
`of heat sink 100. A bevel may be provided along the edge
`wherefirst and second generally rectangular members 110,
`120 join, which increases the thermal mass and reducesther-
`malresistance therebetween.
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`7
`heat fromheat sink 100 is thought to be aided by the exterior
`of heat sink 100, e.g., by the curved outer surfaces of elon-
`gated members 130, being shaped to generally conform geo-
`metrically to the interior surface of housing 20 in which heat
`sink 100 is disposed.
`Becauseheatsink 100,e.g., as in the example embodiment,
`preferablyis sufficient to dissipate and/or distribute heat gen-
`erated by light 10' under normal operation and fault condi-
`tions without having an exposedsurface or being attached to
`a highly thermally conductive case or housing. Thus, the case
`or housing of light 10, 10' need not be madeof a thermally
`conductive material
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`8
`plastic to provide a lens, and from whichtwoelectrical con-
`tacts 212, 214 extend for makingelectrical connectionto the
`diode element.
`Electronic circuit board 220 typically has two conductive
`areas 202, 204 to whichelectrical contacts 212,214 of LED
`210 are electrically and mechanically connected, e.g., by
`solderingor by electrically conductive adhesive, so that LED
`210 and circuit board 220 are attached to each other and may
`be handled as an assembly 200. Conductors 340 may be
`electrically connected to conductive areas 202, 204ofcircuit
`board 220, e.g., by soldering or by electrically conductive
`adhesive. Circuit board 220 is conveniently circular in shape
`and has a central opening 206 into which LED 210 is disposed
`Typically, certain external surfaces ofheat sink 100 may be
`when contacts 212, 214 are connected to conductive areas
`shaped to conform to the inside configuration of a case or
`202, 204. Specifically, the integral heat sink of LED 210 is
`housing,e.g., in the example embodiment, elongated mem-
`bers 130 are extended and have curved outer surfaces to
`disposed in opening 206 so that it is exposed at the rear of
`LED assembly 200 and may be bondedto circular area 112 of
`conform to the height and shape of a housingthat hasaflat
`heat sink 100.
`rear surface and curvedside surfaces. Such housing may have
`LED assembly 200is preferably attached to circular area
`a flat top surface through which actuator 322 of switch 320
`112 offirst generally rectangular member 110 of heat sink
`maybe actuated,either directly or through a flexible boot or
`button.
`100 by bonding with a thermally conductive adhesive so as to
`provide for the conduction ofheat from LED 210 to heat sink
`FIG.4 is an exploded isometric view of heat sink 100 and
`100, thereby to reduce the temperature to which LED 210
`LED assembly 200 ofthe example embodimentofalight 10'
`rises when energized to less than, e.g., 200° C. Desirably,
`according to FIGS. 1-3. Heat sink 100 and LED assembly 200
`an
`because LED 210is exposedat the rear of LED assembly 200
`are described above and so that description will not be 2
`through opening 206, the heat sink integral to LED 210 is
`repeated here exceptin relation to certain features more evi-
`thermally bonded directly to heat sink 100,
`thereby to
`dent in FIG.4.
`increase heat transfer from LED 210 to heat sink 100.It is
`noted that circuit board 220 maybeprovided for convenience
`in assembly andattachment of LED 210 to heat sink 100 and
`in making electrical connections to LED 210, but circuit
`board 220 is not necessary to the satisfactory operation of
`light 10, 10' as described.
`LED 210 is desirably placed in a predetermined location on
`heat sink 100 so that when heat sink 100is in light 10, LED
`210 and reflector 30 of light 10 will be in desired relative
`positions for producing a beam oflight of a desired shape.
`Properrelative positioning may be provided by positioning
`Second generally rectangular member 120 is seen to have
`and bonding LED 210 onheat sink 100 within suitable toler-
`a generally planarraised area 122 against which one end of
`ance, and by positioning heat sink 100 in light 10 within
`circuit board 300 maybear,preferablythe end ofcircuit board
`suitable tolerance. To this end, heat sink 100 may include
`300 that carries electronic components that generate heat
`alignment features, e.g., alignment holes 116,to aid in prop-
`under normaloperation and/or underfault conditions. Slot or
`erly positioning LED 210 in relation to heat sink 100.
`hole 124therein is for receiving fastener 305 which attaches
`For example, heat sink 100 may include two or more align-
`circuit board 300 to second generally rectangular member
`mentholes 116 the locations of which are accurately known
`120. Raised ridge 126 maybeflat at its top and may provide
`withrespectto the centerofcircular area 112 ofheat sink 100.
`support for circuit board 300 in a region thereof underelec-
`An alignment tool may be provided that has two alignment
`trical switch 320 so that circuit board 300 can withstand any
`features that are in knownpositions for engaging alignment
`stress caused by auserpressing on actuator 322 ofswitch 320.
`features 116 of heat sink 100, e.g., two posts or projections
`Area 122 and ridge 126 definearecess 125 therebetween and
`that maybe insertedinto alignment holes 116. The alignment
`ridge 126 and elongated member130 definea recess therebe-
`tool mayalso have a recess into which LED 210,specifically
`tween that may provide clearance between second generally
`the plastic lens ofLED 210,fits so as to be ina knownposition
`rectangular member 120 andcircuit board 300 for leads of
`relative to the alignment projections thereof that engage
`electronic components andsolderareasofcircuit board 300.
`alignment holes 116. Thus, when LED 210 or LED assembly
`Because raised area 122 and raised ridge 126 increase the
`200 is placed in the alignmenttool and the alignment tool is
`thickness of second generally rectangular member 120, they
`placed adjacent heat sink 100 with its alignment projections
`also reduce the thermal resistance and increase the thermal
`in alignmentholes 116 ofheat sink 100, LED 210 will be in
`massofheat sink 100.
`the desired location on heat sink 100 to within the desired
`tolerance, thereby to properly align with reflector 30 of light
`10.
`Alternatively and optionally, circuit board 220 may have an
`alignment hole 222 therein for positioning LED 210 in a
`know