# US 7,710,045 B2 · Illumination assembly with enhanced thermal conductivity > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,710,045 B2 - Document ID: US7710045B2 - Status: Granted - Kind: B2 - Application number: 11/276,901 - Filed: 2006-03-17 - Published: 2007-09-20 - Granted: 2010-05-04 - Earliest claimed: 2006-03-17 - Assignees: 3M Innovative Properties Company - Inventors: John C. Schultz; Nelson B. O'Bryan - Web page: https://patentgrep.com/patent/US7710045B2 ## CPC - H05K 1/0204: {using means for thermal conduction connection in the thickness direction of the substrate (H05K1/0207 takes precedence)} - H05K 1/0209: {External configuration of printed circuit board adapted for heat dissipation, e.g. lay-out of conductors, coatings} - H05K 1/0373: {containing additives, e.g. fillers (H05K1/036 takes precedence)} - F21K 9/00: Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers - G02F 1/133628: {with cooling means} - H05K 1/189: characterised by the use of flexible or folded printed circuits - H05K 3/0061: {onto a metallic substrate, e.g. a heat sink (heat sinks for electric apparatus H05K7/20)} - H05K 2201/0209: Inorganic, non-metallic particles - H05K 2201/09318: Core having one signal plane and one power plane - H05K 2201/09363: wherein only contours around conductors are removed for insulation - H05K 2201/10106: Light emitting diode [LED] - H05K 2203/1189: Pressing leads, bumps or a die through an insulating layer - H10W 72/536: {the connected ends being ball-shaped} - H10W 72/5363: {the connected ends being wedge-shaped} - H10W 72/884: {Die-attach connectors and bond wires} - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - F21K: NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract Illumination assemblies include a substrate having a first and second electrically conductive layer separated by an electrically insulating layer. The insulating layer includes a polymer material loaded with thermally conductive particles. At least a portion of the thermally conductive particles simultaneously contact both the first and second electrically conductive layers. A plurality of light sources such as LEDs or other miniature light sources are preferably disposed on the first conductive layer. ## Claims ### Claim 1 An illumination assembly, comprising: a substrate comprising a first and second electrically conductive layer separated by an electrically insulating layer, the insulating layer comprising a polymer material loaded with thermally conductive particles, wherein at least a portion of the thermally conductive particles simultaneously contact both the first and second electrically conductive layers and extend partially into at least one of the first and second electrically conductive layers, wherein the thermally conductive particles are not deformed and at least one of the first and second electrically conductive layers are deformed by the thermally conductive particles sufficiently to eliminate an interface of the polymer material between the thermally conductive particles and the at least one of the first and second electrically conductive layers into which the portion of the thermally conductive particles extend, and wherein the thermally conductive particles penetrate the at least one of the first and second electrically conductive layers beyond the eliminated interface; and a plurality of light sources disposed on the first conductive layer. ### Claim 2 (depends on 1) The assembly of claim 1, wherein the light sources are selected from the group of LEDs, laser diodes, and OLEDs. ### Claim 3 (depends on 1) The assembly of claim 1, wherein the thermally conductive particles comprise particles selected from the group of barium titanate, barium strontium titanate, titanium oxide, lead zirconium titanate, boron, boron nitride, diamond, alumina, beryllium, silicon, and any carbides, oxides, and nitrides thereof. ### Claim 4 (depends on 1) The assembly of claim 1, further comprising dielectric particles having a dielectric constant of at least 100 loaded in the polymer material of the insulating layer, wherein the dielectric particles do not simultaneously contact both the first and second electrically conductive layers. ### Claim 5 (depends on 1) The assembly of claim 1, wherein the thermally conductive particles are non-uniformly distributed in the insulating layer. ### Claim 6 (depends on 4) The assembly of claim 4, wherein the thermally conductive particles are concentrated near the light sources. ### Claim 7 (depends on 1) The assembly of claim 1, wherein at least one of the first and second electrically conductive layers comprises a foil. ### Claim 8 (depends on 1) The assembly of claim 1, wherein the first electrically conductive layer is patterned to form one or more traces. ### Claim 9 (depends on 1) The illumination assembly of claim 1, wherein the second electrically conductive layer comprises a heat sink. ### Claim 10 (depends on 1) The assembly of claim 1 in combination with: a heat sink; and a layer of thermal interface material disposed between the heat sink and the second conductive layer. ### Claim 11 (depends on 1) A backlight for a display, comprising the assembly of claim 1. ### Claim 12 A method of making an illumination assembly, the method comprising: supplying a substrate comprising a first and second electrically conductive layer separated by an electrically insulating layer, the insulating layer comprising thermally conductive particles, wherein at least a portion of the thermally conductive particles simultaneously contact both the first and second electrically conductive layers and extend partially into at least one of the first and second electrically conductive layers, wherein the thermally conductive particles are not deformed and at least one of the first and second electrically conductive layers are deformed by the thermally conductive particles sufficiently to eliminate an interface of the polymer material between the thermally conductive particles and the at least one of the first and second electrically conductive layers into which the portion of the thermally conductive particles extend, and wherein the thermally conductive particles penetrate the at least one of the first and second electrically conductive layers beyond the eliminated interface; patterning the first electrically conductive layer; and providing a plurality of light sources on the patterned first electrically conductive layer. ### Claim 13 (depends on 12) The method of claim 12, wherein the supplying step comprises: applying a layer of electrically insulative polymer material on the second electrically conductive layer; applying the thermally conductive particles on the layer of polymer material; and laminating the first electrically conductive layer over the thermally conductive particles to force the thermally conductive particles into simultaneous contact with both the first and second electrically conductive layers. ### Claim 14 (depends on 13) The method of claim 13, wherein applying a layer of electrically insulative polymer material comprises loading the polymer material additionally with particles that are smaller than a thickness of the layer of electrically insulative polymer material, the particles having a dielectric constant of at least 100. ### Claim 15 (depends on 13) The method of claim 13, wherein applying the thermally conductive particles comprises applying the thermally conductive particles in a pattern. ### Claim 16 (depends on 12) The method of claim 12, wherein the supplying step comprises: applying a layer of electrically insulative polymer material having the thermally conductive particles dispersed therein on at least one of the first or second electrically conductive layer; and laminating the first electrically conductive layer over the thermally conductive particles to force the thermally conductive particles into simultaneous contact with both the first and second electrically conductive layers. ### Claim 17 (depends on 12) The method of claim 12, wherein the supplying step comprises unwinding a roll of the substrate. ### Claim 18 (depends on 17) The method of claim 17, further comprising cutting the substrate at intervals to provide a plurality of illumination assembly strips, panels, or other shapes suitable for mounting in an illumination unit.