Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS20070091618 A1
Publication typeApplication
Application numberUS 11/640,645
Publication dateApr 26, 2007
Filing dateDec 14, 2006
Priority dateJun 15, 2004
Also published asCA2589570A1, CA2589570C, CN100594327C, CN101031751A, EP1766287A1, EP1766287A4, EP1766287B1, US7540634, US20080273329, WO2006001928A1
Publication number11640645, 640645, US 2007/0091618 A1, US 2007/091618 A1, US 20070091618 A1, US 20070091618A1, US 2007091618 A1, US 2007091618A1, US-A1-20070091618, US-A1-2007091618, US2007/0091618A1, US2007/091618A1, US20070091618 A1, US20070091618A1, US2007091618 A1, US2007091618A1
InventorsRonald Belek
Original AssigneeBelek Ronald E
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
High power led electro-optic assembly
US 20070091618 A1
Abstract
The present invention provides a high power LED electro-optic assembly (40) including conductive heat sink (18) and an LED (14) mounted at one end of the heat sink. The LED (14) is in electrical engagement with the heat sink (18). The assembly (40) also includes a reflector (2) mounted at the other end of the heat sink. An insulating bond material (19) is provided between the reflector and the sink. The assembly (40) further includes a conductive bonding pin (15) extending through the reflector (12) and is in conductive engagement therewith and an electrical engagement (16) which electrically engages the pin (15) to the LED (14). Finally, an electric sleeve assembly (30) where the sleeve (32) is coated with an electrical insulating coating (34) is applied to the LED electro-optic assembly.
Images(5)
Previous page
Next page
Claims(14)
1-19. (canceled)
20. A method of forming a LED electro-optic assembly comprising the steps of;
conductively attaching at least one LED to a conductive heat sink.
surrounding said LED with a conductive reflector, said reflector including a bonding pin extending through; and
electrically engaging said bonding pin to said LED.
21. The method of claim 20 further including the step of:
interposing an insulator between said reflector and said heat sink.
22. The method of claim 20 wherein said surrounding step includes:
disposing an insulative bonding agent between said reflector and said heat sink.
23. The method of claim 20 wherein said wire bonding step includes:
interposing a conductive bonding wire between said pin and said LED.
24. The method of claim 20 wherein said heat sink is a heat pipe.
25. A LED electro-optic retaining assembly comprising:
a generally cylindrical sleeve having an upper portion and a lower portion, said sleeve coated with an electrical insulator;
at least one passage located at an upper portion for insertion of a bonding agent, wherein said upper portion is modified to retain said electro-optic.
26. The assembly of claim 25 wherein said sleeve is constructed from aluminum or an alloy thereof.
27. The assembly of claim 25 wherein said bonding agent provides a conductive engagement between the sleeve and a metal contact inside the upper portion.
28. The assembly of claim 27 wherein said bonding agent is a conductive adhesive.
29. The assembly of claim 27 wherein said bonding agent is a wire.
30. The assembly of claim 27 wherein said upper portion includes a first electrode member and press fit reflectivity surface mounted therein.
31. The assembly of claim 27 wherein said lower portion includes a second electrode member with electrically conducting heat sink mounted therein.
32-40. (canceled)
Description
    FIELD OF INVENTION
  • [0001]
    The present invention relates to light emitting diode (“LED”) technology, particularly to improvements in LED assemblies to provide a desired optical output for various lighting applications.
  • BACKGROUND OF THE INVENTION
  • [0002]
    LED assemblies are well-known and commercially available. Such assemblies are employed in a wide variety of applications, typically for the production of ultraviolet radiation, used, for example, in effecting the curing of photo initiated adhesives and coative compositions.
  • [0003]
    Several factors play into the fabrication of LED assemblies. One is the control of high current supplied to the LEDs to provide a stable and reliable UV source. Another is the position of the lens to hold the output optic in place. Also, a means to provide a path for electrical conduction is required to supply control for the LED. As the current increases to the LED, the need for a high current, high reliability electrical contact becomes necessary. Additionally, a reflector forming the rays coming from the LED is often required. Furthermore, a cooling system is required to carry the heat away from the assembly. Presently, available, LED assemblies may not adequately offer all of these requirements.
  • [0004]
    Currently, manufacturers are providing a wide range of LED packages in a variety of forms. These packages range from conventional LED lamps to LEDs that use emitter chips of various sizes. While, many of the known LED assemblies produce a high light output, they produce a very disperse wide angle beam that is difficult to capture for efficient collimation and beam imaging in practical application, such as in a flashlight. As a result, a great deal of the output energy is lost as leakage out from the side of the LED package.
  • [0005]
    Additionally, light emitted from the LED assembly is ordinarily not evenly distributed. The shape of the light-emitting chip is projected on the target as a high intensity area. Reflections from the electrodes and walls from unpredictable patterns of light are superimposed on the main beam of light. As a result, undesirable hot spots and shadows appear on the object being illuminated. Accordingly, for any lighting application requiring a substantially even or uniform distribution of light over a predetermined area, a transmitting or partial diffuser must be used to scatter the light emitted from each individual LED assembly so that the hot spots and shadows do not appear on the object being illuminated. But, while a diffuser will eliminate hot spots and shadows, it is important that the “directivity” or geometry of the light beam emitted from an individual LED assembly not be degraded or diminished.
  • [0006]
    In order to overcome these above-noted disadvantages of known light sources, there is a need to provide an LED curing lamp assembly that has a flexible design, is easy to manufacture and reduces assembly cost.
  • SUMMARY OF THE INVENTION
  • [0007]
    In one embodiment of the present invention there is disclosed a LED electro-optic electrical sleeve assembly having a generally cylindrical sleeve coated with an electrical insulator. The assembly is divided into an upper portion and a lower portion, the upper and lower portion separated by an insulating material. At least one LED and a conductive reflector is mounted at the upper portion, where the reflector surrounds the LED. A conductive heat sink is mounted at the lower portion, and is in electrical engagement with the LED. Additionally a conductive bonding pin extends through the conductive reflector and is in conductive engagement therewith. An electrical engagement electrically engages the bonding pin to the LED, where the heat sink and the reflector form an electrically conductive location for supplying power to said LED.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0008]
    FIG. 1 is a schematic view of a LED ray forming contact assembly of the present invention.
  • [0009]
    FIG. 2 is a schematic view of a LED optical transform assembly using the ray forming contact assembly of FIG. 1.
  • [0010]
    FIG. 3 is a schematic view of an electrical sleeve assembly of the present invention.
  • [0011]
    FIG. 4 is a schematic view of a LED, Electro-optic Assembly of the present invention.
  • DETAILED DESCRIPTION OF THE INVENTION
  • [0012]
    Referring to FIG. 1 of the present invention, there is shown a schematic view of a LED ray forming contact assembly 10. The assembly 10 is a compact means of providing a way to simultaneously contact the LED with electrical contacts and form the rays coming from the LED as will be described hereinbelow. The contact assembly 10 is divided into two contacts, i.e., electrodes, an upper electrode 10 a and lower electrode 10 b, both made of metal. The upper electrode 10 a includes a metal reflector 12 preferably made of aluminum. The metal reflector 12 is press fit into the electrode 10 a to form a conductor reflector assembly. The metal reflector 12 may be shaped as a curve and functions to generally collimate and direct the LED light towards the lens and will be described in greater detail below. In a preferred embodiment, the reflector 12 is shaped as an elliptic. A LED chip 14 is mounted in the electrode 10 a, desirably positioned at the center and partially or wholly surrounded by the reflector 12. The LED chip 14 is further electrically isolated from the reflector 12. Because metal is a good electrical conductor, both the metal reflector 12 and the metal electrode 10 a provide an electrical transfer path away from the LED chip 14. A conductive metal pin 15 desirably coated with gold is pressed into the assembly 10 in the upper electrode 10 a as shown in FIG. 1. An electrical engagement such as a gold wire or wires 16 passes from the upper electrode 10 a to the lead chip 14. One end of the gold wire 16 is soldered to the metal pin 15 and the other end is welded to the top surface of the LED chip 12 to electrically engage the pin 15 with the LED 14.
  • [0013]
    When current flows through a chip in an individual LED assembly, both light and heat are generated. Increasing the current through the chip raises the light output but increased current flow also raises the temperature of the chip in the individual LED assembly. This temperature increase lowers the efficiency of the chip. Overheating is the main cause of the failure of individual LED assemblies. To assure safe operation, either the current, and as a result the light output, must be kept at a low level or some other means of transferring heat away from the chip in the individual LED assembly must be provided. Therefore, lower electrode 10 b may be defined by with an electrically conducting thermal heat sink 18 which also serves to carry heat away from the LED chip 14. The upper electrode 10 a and the lower electrode 10 b are held together by an electrically insulating material 19 such as a non-conductive adhesive. The LED 14 is disposed in the assembly 10 in such a manner that the bottom surface is bonded or soldered to the thermal heat sink 18 via the bond material 19. In order to allow the electrical connection through the LED 14, voltage is applied to both upper and lower electrodes 10 a and 10 b respectively. This causes the heat sink 18 to carry off heat and the curved surface of the reflector 12 forms the light from the LED 14 into a desired pattern. Even though only single LED 14 is shown in FIG. 1, it is understood that multiple LEDs can be employed in the assembly 10.
  • [0014]
    By providing one of the electrical contacts 10 a in conjunction with the reflector and the other electrical contact 10 b in conjunction with thermal heat sink, the LED ray forming contact assembly 10 is easy to manufacture, reduces the assembly cost and simplifies the final assembly. Furthermore, the LED ray forming contact assembly 10 also allows the scaling up to multiple LEDs in an assembly without adding significant complexity.
  • [0015]
    To further exemplify the operation of the entire optical assembly FIG. 2A-FIG. 2C illustrate an exemplary ray diagrams for a single LED assembly. It will be understood by those skilled in the art that a similar ray diagram results when the LED chip 14 of the single LED assembly is replaced by multiple LED chips 14.
  • [0016]
    FIG. 2A-FIG. 2C show a LED optical transform assembly 20 using the LED forming contact assembly 10 of FIG. 1 in conjunction with miniature optical components to form a complete ray forming system. The optical components include a lens 22 that directs the light generated by the LED chip 14 by focusing the light to a desired spot size by collimating the light to a desired location. The lens 22 may be attached or molded precisely in the assembly so that it is centered at the collimated beam. The shape and/or size of the lens 22 may vary to shape the conical beam of light emitted from the LED assemblies to provide the desired optical illumination pattern.
  • [0017]
    The converging action of the lens 22 depends on both the radius of lens 22 and the positioning of the lens 22 with respect to the individual LED assembly 20. Both the radius and position of the lens 22 may be established during the design process to optimize illumination of the object. The ability to precisely locate and fixture the optic lens 22 is a critical concept in this application. The lens 22 needs to be positioned at right distance from the LED 14 in order to achieve the desired light output.
  • [0018]
    In FIG. 2A, an optical lens 22 a in shape of ball is partially located in the reflector 12 of the upper electrode 10 a. Even though a ball shaped optic lens 22 a is shown in the present invention, it is understood that other different shapes of optics can be selected. The optics can be varied depending on the desired output. In the present invention, ball optic 22 a is selected in order to produce the maximum light power density with the available LED output. The LED output is focused to a desired spot just outside the ball optic lens 22 a. If a collimated beam is desired, a half ball optical lens 22 b as shown in FIG. 2B or a parabolic optical lens 22 c shown in FIG. 2C may desirably be used. The parabolic optical lens 22 b of FIG. 2B is positioned in such a manner that part of the lens lies in the reflector 12 and the other part is outside the assembly 20. This positioning of lens 22 b emits a wide light pattern as shown in FIG. 2B thereby illuminating a much bigger area on a work piece. Whereas, the parabolic optical lens 22 c, as shown in FIG. 2C, is positioned completely outside the reflector 12 and/or the assembly 20. This positioning of lens 22 c in FIG. 2C emits a narrower light pattern than the area in FIG. 2B thereby illuminating a specific area on a work piece. This method provides a rigid assembly that can be manufactured precisely and rapidly. The LED ray forming contact assembly size, other optics lenses 22 can preferably be modified and further distances and positions between the LED 14 and the lens 22 can be varied to accommodate a wide range of optical components while minimizing the cost and complexity of the complete assembly.
  • [0019]
    The number of LED assemblies employed determines the size of a LED array and the desired output intensity. An end user can easily increase or decrease the output intensity by adding/removing LED assemblies to/from the LED array. Also, a user can change the operating wavelength of the assembly by replacing one or more LED assemblies of a first operating wavelength with one or more replacement assemblies having a second wavelength. In addition, a user can replace damaged or expired LED assemblies without replacing the entire LED array.
  • [0020]
    Regarding the optical properties of the optical assembly 10 and 20, each, LED 14, emits diffuse light at a predetermined optical power and a predetermined optical wavelength. Exemplary LEDs 14 according to the present invention emit preferably greater than 500 mw of optical power at desirably 405 nm. The reflective cavity collimates a majority of the diffuse light emitted by the LED 14 when the LED 14 is placed at the desired location within the reflective cavity. The parabolic reflector 12 represents an exemplary reflective cavity that collimates the majority of the light when the LED 14 is placed at or near the focal point of elliptic reflector 12, as shown in FIG. 2. It will be understood by those skilled in the art that the collimating means of the present invention is not limited to an elliptical reflector 14. Other LED collimating means well understood by those skilled in the art may also be implemented in the present invention.
  • [0021]
    In order to make small optical assemblies, preferably such as LED optical assemblies, it is necessary to have a means to hold the output optic in place and also provide a path for electrical conduction. One such means is an electrical sleeve assembly 30 shown in FIG. 3. The assembly 30 is preferably conducted of aluminum alloy including a generally cylindrical sleeve 32 preferably made of aluminum coated with an electrical insulating coating 34 such as a non-conductive adhesive. The outside of the sleeve 32 is masked to allow contact with an external electrical connection as will be described in greater detail below. The assembly 30 shows a cutaway drawing with slots 36 at upper ends as shown in FIG. 3. These slots 36 are preferably machined into the sleeve after the sleeve 32 has been coated. Since the slots 36 now allow bare metal assembly 30 to be exposed over a large area, the total exposed surface provides a very low resistance contact when the conductive coating such as an adhesive is applied between the sleeve slots 36 and the metal contact inside the sleeve 36. The conductive adhesive connects the reflector 12 inside the assembly to the outside sleeve 32. Alternatively, a wire bonding may be applied to bond the reflector 12 to the sleeve 32. The two slots 36 provide four open surfaces to make contact with the sleeve 32. Furthermore, the electrical conductivity is maximized due to the length of the slots 36 and due to the fact that two surfaces for each of the two slots 36 provide a maximum surface area in a compact assembly. The shape of upper ends of the sleeve 32 are preferably modified to retain an optic that is being used with assembly 30. By simply placing an optic in the sleeve 32 and sliding onto preferably a LED assembly, then applying the conductive adhesive to the slots 36 or wire bonding the reflector 12 to the sleeve 32, an electro-optic assembly is electrically connected, as will be described in greater detail below with reference to FIG. 4.
  • [0022]
    The LED 14 is combined with the ray forming contact assembly 10, LED variable optical assembly 20 and the LED lens retaining electrical sleeve assembly 30 to form a complete LED electro-optic assembly 40 as shown in FIG. 4. LED 14 is bonded or soldered to the thermal heat sink 18 made of an electrically conductive material. Once the LED 14 is contacted to the thermal heat sink 18 with the insulating material 19, the ray forming contact assembly 10 is bonded in place. Again, the top surface of the LED 14 is bonded to the conductive metal pin 15 via the gold wire 16. The pin 15 is preferably coated with gold and is pressed into the metal contact assembly. Because the contact assembly metal is selected for reflectivity and electrical conductivity, it will direct the LED output and serve to electrically connect the top surface of the LED 14 to the outside surface of the ray forming contact assembly 10. Next, the LED variable optical assembly 20 is installed preferably with a ball optic lens 22 a.
  • [0023]
    Finally, the LED lens retaining electrical sleeve assembly 30 is installed while applying the structural adhesive 34 on the thermal heat sink 18. The reflector 12 is preferably bonded to the thermal heat sink 18 with the structural adhesive 34. So, the structural adhesive 34 functions to hold the assembly securely together, providing some thermal conduction and additional electrical insulation from the thermal heat sink 18. Additionally, a conductive adhesive 36 is preferably applied to the slots 36 to bond the outside sleeve 32 to the reflector 12. Alternatively, as discussed above, a wire, preferably aluminum (not shown) may be used to wire bond between the reflector 12 inside the assembly and the outside sleeve 32 preferably made of aluminum. Preferably, multiple wire bonds are used to bond the reflector 12 and a recess (not shown) below the surface of the outside sleeve 32. Also, the recess is desirably coated for protection. The conductive material is heat cured and the complete LED electro-optic assembly 40 is formed. Again, the assembly 40 shows only a single LED 14, multiple LED devices may preferably be bonded to the assembly.
  • [0024]
    Individual alignment of the LED 14 or multiple LEDs is required because no two individual LED assemblies are exactly the same. Differences arise from the positioning of the chip 14 inside the reflector 12, the positioning of the reflector cup 12, the positioning of the electrodes 10 a and 10 b, and the positioning of the optic lens 22. All of these factors affect the geometry and direction of the beam of light. Due to the manufacturing process of individual LED assemblies, the components in individual LED assemblies exhibit a very wide range of positional relationships. Therefore, for any application that requires illumination of a specific area, each individual LED assembly must be manually aligned and then permanently held in place by some means of mechanical support.
  • [0025]
    While a single LED is used herein to illustrate the invention, it will be understood by those skilled in the art that the invention described herein applies to a plurality of LEDs or LED array. A plurality of LEDs may be arranged in any manner as desired for illumination.
  • [0026]
    Even though, in the present invention the LED 14 is shown to be a rectangular frame, those of ordinary skill in the art will understand that according to the disclosed invention, LED illuminators may be formed in any shape suitable to provide light for a wide array of applications, including but not limited to photocuring, video, shop windows, photography or specialty product displays. Because of the durability and rugged construction of the disclosed LED illuminator, it may be used in outdoor settings, marine applications, or hostile environments.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3512027 *Dec 12, 1967May 12, 1970Rca CorpEncapsulated optical semiconductor device
US4346329 *Sep 26, 1980Aug 24, 1982Schmidt Robert C HAiming post light
US4742432 *Nov 19, 1985May 3, 1988U.S. Philips CorporationMatrix of light-emitting elements and method of manufacturing same
US4764804 *Feb 17, 1987Aug 16, 1988Hitachi, Ltd.Semiconductor device and process for producing the same
US5160200 *Mar 6, 1991Nov 3, 1992R & D Molded Products, Inc.Wedge-base LED bulb housing
US5387800 *Aug 19, 1992Feb 7, 1995Dymax CorporationPrefocused lamp and reflector assembly
US5660461 *Dec 8, 1994Aug 26, 1997Quantum Devices, Inc.Arrays of optoelectronic devices and method of making same
US5698866 *May 28, 1996Dec 16, 1997Pdt Systems, Inc.Uniform illuminator for phototherapy
US6045240 *Oct 20, 1997Apr 4, 2000Relume CorporationLED lamp assembly with means to conduct heat away from the LEDS
US6113212 *Apr 16, 1998Sep 5, 2000Eastman Kodak CompanyMethod and apparatus for thermal control of LED printheads
US6159005 *May 15, 1998Dec 12, 2000Espe Dental AgPhotopolymerization apparatus
US6492725 *Feb 4, 2000Dec 10, 2002Lumileds Lighting, U.S., LlcConcentrically leaded power semiconductor device package
US6523959 *Dec 14, 2001Feb 25, 2003Industrial Technology Research InstituteCooling device for liquid crystal projectors
US6552368 *Sep 28, 2001Apr 22, 2003Omron CorporationLight emission device
US6614103 *Sep 1, 2000Sep 2, 2003General Electric CompanyPlastic packaging of LED arrays
US6827468 *Dec 10, 2002Dec 7, 2004Robert D. GalliLED lighting assembly
US6831305 *Apr 10, 2002Dec 14, 2004Toyoda Gosei Co., Ltd.Semiconductor light-emitting device
US6921971 *Jan 15, 2004Jul 26, 2005Kyocera CorporationHeat releasing member, package for accommodating semiconductor element and semiconductor device
US6940102 *Feb 8, 2002Sep 6, 2005Agilent Technologies, Inc.Light-emitting diode and a method for its manufacture
US6999318 *Jul 28, 2003Feb 14, 2006Honeywell International Inc.Heatsinking electronic devices
US7497596 *Dec 30, 2002Mar 3, 2009Mane LouLED and LED lamp
US20030000213 *Dec 15, 2000Jan 2, 2003Christensen Richard N.Heat engine
US20030036031 *May 15, 2002Feb 20, 2003Lieb Joseph AlexanderLight-emitting handpiece for curing photopolymerizable resins
US20030219693 *Dec 13, 2001Nov 27, 2003Cao Group, Inc.Dental curing light
US20040032728 *Aug 7, 2003Feb 19, 2004Robert GalliOptical assembly for LED chip package
US20040070990 *Oct 1, 2002Apr 15, 2004Witold SzypszakLED illuminator and method of manufacture
US20040090794 *Nov 8, 2002May 13, 2004Ollett Scott H.High intensity photocuring system
US20050135105 *Dec 19, 2003Jun 23, 2005Lumileds Lighting U.S., LlcLED package assembly
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7505268 *Apr 5, 2006Mar 17, 2009Tir Technology LpElectronic device package with an integrated evaporator
US8066406Oct 17, 2008Nov 29, 2011Lsi Industries, Inc.Optic positioning device
US8165434 *Mar 17, 2009Apr 24, 2012LumenFlow Corp.High efficiency optical coupler
US20060261470 *Apr 5, 2006Nov 23, 2006Tir Systems Ltd.Electronic device package with an integrated evaporator
US20100239207 *Mar 17, 2009Sep 23, 2010LumenFlow Corp.High efficiency optical coupler
US20120217519 *Nov 19, 2010Aug 30, 2012Appotronics Corporation LimitedMethod and structure for encapsulating solid-state light emitting chip and light sources using the encapsulation structure
US20160106872 *Jan 30, 2015Apr 21, 2016Seth MartinezHandheld device for destroying microorganisms
EP2201285A1 *Oct 17, 2008Jun 30, 2010LSI Industries, Inc.Optic positioning device
EP2201285A4 *Oct 17, 2008Mar 21, 2012Lsi Industries IncOptic positioning device
EP2317215A1 *Oct 28, 2010May 4, 2011Volker MannheimLight with at least one LED
WO2009055314A1Oct 17, 2008Apr 30, 2009Lsi Industries, Inc.Optic positioning device
Classifications
U.S. Classification362/345, 362/294, 257/E33.072
International ClassificationH01L33/64, F21V29/00, F21V7/20
Cooperative ClassificationF21V29/006, F21V29/004, F21Y2101/00, H01L33/647, F21V29/70, F21V29/51, F21V29/505, H01L2224/48247, Y10S362/80, G02B19/0061, G02B19/0028, F21V5/041, H01L33/58, H01L33/648, H01L33/62, B29C65/54, H01L33/60, B29C66/61, H01L2224/45124, H01L2224/45144, B29C66/5344, B29C65/4835, B29C65/4855, B29C65/4845
European ClassificationB29C66/61, B29C66/534, B29C65/54, H01L33/64F, F21V5/04B, G02B17/08N1, F21V7/20, F21V29/00C2
Legal Events
DateCodeEventDescription
Jan 31, 2012ASAssignment
Owner name: DATA CLOAK LLC, DELAWARE
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HENKEL CORPORATION;REEL/FRAME:027626/0508
Effective date: 20111208