# US 7,611,271 B2 · Efficient light injector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,611,271 B2 - Document ID: US7611271B2 - Status: Granted - Kind: B2 - Application number: 11/688,102 - Filed: 2007-03-19 - Published: 2008-09-25 - Granted: 2009-11-03 - Earliest claimed: 2007-03-19 - Assignees: 3M Innovative Properties Company - Inventors: Michael A. Meis; David J. Lundin; Scott D. Gullicks; Charles D. Hoyle - Web page: https://patentgrep.com/patent/US7611271B2 ## CPC - G02B 6/4203: {Optical features} - G02B 6/0006: {Coupling light into the fibre (in general G02B6/4298)} - G02B 6/262: {Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements} - G02B 6/4212: {the intermediate optical element being a coupling medium interposed therebetween, e.g. epoxy resin, refractive index matching material, index grease, matching liquid or gel} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A light injector includes a tapered solid light guide having a light input end, an opposing light output end, and a total internal reflection surface defining a longitudinal outer surface there between. The light input end includes an aperture extending into the tapered solid light guide defined by an aperture surface. A specularly reflective layer or film is disposed adjacent to the total internal reflection surface. A distance between the specularly reflective layer or film and the total internal reflection surface defines a first air gap. The aperture is configured to accept a lambertian light source. ## Claims ### Claim 1 A light injector comprising: a tapered solid light guide having a light input end, an opposing light output end, and a total internal reflection surface defining a longitudinal outer surface there between, the light output end having a larger circumference than the light input end, and the light input end includes an aperture extending into the tapered solid light guide defined by an aperture surface; and a specularly reflective layer or film disposed adjacent to the total internal reflection surface, wherein a distance between the specularly reflective layer or film and the total internal reflection surface defines a first air gap, wherein the aperture is configured to accept a lambertian light source and 97% or greater of light emitted by a lambertian light source is emitted from the light output end. ### Claim 2 (depends on 1) A light injector according to claim 1, wherein 98% or greater of light emitted by a lambertian light source is emitted from the light output end. ### Claim 3 (depends on 1) A light injector according to claim 1, further comprising a lambertian light source disposed within the aperture. ### Claim 4 (depends on 3) A light injector according to claim 3, wherein the lambertian light source is optically coupled to the tapered solid light guide with an index matching gel or adhesive. ### Claim 5 (depends on 3) A light injector according to claim 3, wherein a distance between the aperture surface and the lambertian light source defines a second air gap. ### Claim 6 (depends on 1) A light injector according to claim 1, wherein the tapered solid light guide is a conical solid light guide. ### Claim 7 (depends on 1) A light injector according to claim 1, wherein the specularly reflective layer is a multilayer polymeric mirror film reflecting greater than 95% of incident light at any angle on the multilayer polymeric film. ### Claim 8 (depends on 1) A light injector according to claim 1, wherein the first air gap surrounds the total internal reflection surface. ### Claim 9 (depends on 1) A light injector according to claim 1, wherein the aperture surface is defined by a curved aperture surface. ### Claim 10 (depends on 1) A light injector according to claim 1, wherein the tapered solid light guide is configured to substantially fill the light output end numerical aperture with light emitted by the lambertian light source. ### Claim 11 (depends on 1) A light injector according to claim 1, wherein the tapered solid light guide is configured to substantially collimate light being emitted from the light output end. ### Claim 12 (depends on 1) A light injector according to claim 1, wherein the tapered solid light guide is configured to collimate light emitted by a lambertian light source from the light output end along a first axis and collimate light being emitted from the light output end along a second axis orthogonal to the first axis. ### Claim 13 A light injector assembly comprising: an elongate tube comprising a first end, an opposing second end, and a tube length there between, the elongate tube having an inner surface and a specularly reflective layer or film disposed adjacent to the inner surface, the first end configured to accept a lambertian light source; and a tapered solid light guide disposed within the elongate tube, the tapered solid light guide having a light input end, an opposing light output end, and a total internal reflection surface defining a longitudinal outer surface there between, and a first air gap is defined by a distance between the specularly reflective layer or film and the total internal reflection surface, the light output end having a larger circumference than the light input end, and the light input end includes an aperture extending into the tapered solid light guide defined by an aperture surface, wherein the aperture is configured to accept a lambertian light source and 97% or greater of light emitted by a lambertian light source is emitted from the light output end. ### Claim 14 (depends on 13) A light injector assembly according to claim 13, wherein 98% or greater of light emitted by a lambertian light source is emitted from the light output face. ### Claim 15 (depends on 13) A light injector assembly according to claim 13, wherein the aperture surface is defined by a curved aperture surface. ### Claim 16 (depends on 13) A light injector assembly according to claim 13, wherein the tapered solid light guide is a conical solid light guide. ### Claim 17 (depends on 13) A light injector assembly according to claim 13, further comprising a lambertian light source at the first end of the elongate tube and the lambertian light source is optically coupled to the tapered solid light guide with an index matching gel or adhesive. ### Claim 18 (depends on 13) A light injector assembly according to claim 13, further comprising a lambertian light source at the first end of the elongate tube and a distance between the aperture surface and the lambertian light source defines a second air gap. ### Claim 19 (depends on 13) A light injector assembly according to claim 13, wherein the specularly reflective layer is a multilayer polymeric mirror film reflecting greater than 95% of incident light at any angle on the multilayer polymeric film. ### Claim 20 (depends on 13) A light injector assembly according to claim 13, wherein the elongate tube further includes a mounting flange. ### Claim 21 A method of forming a light injector assembly comprising: providing an elongate tube comprising a first end, an opposing second end, and a tube length there between, the elongate tube having an inner surface and a specularly reflective layer or film disposed adjacent to the inner surface, and a lambertian light source disposed adjacent to the first end; providing a tapered solid light guide, the tapered solid light guide having a light input end, an opposing light output end, and a total internal reflection surface defining a longitudinal outer surface there between, the light output surface having a larger circumference than the light input end, and the light input end includes an aperture extending into the tapered solid light guide defined by an aperture surface; and inserting the tapered solid light guide into the elongate tube such that the lambertian light source is disposed within the aperture and spaced apart from the aperture surface by a first air gap and the total internal reflection surface is spaced apart from the elongate tube inner surface by a second air gap, to form a light guide assembly and 97% or greater of light emitted by a lambertian light source is emitted from the light output end. ### Claim 22 (depends on 21) A method according to claim 21, wherein the inserting step comprises coupling the tapered solid light guide to the elongate tube. ### Claim 23 (depends on 21) A method according to claim 21, further comprising mounting the elongate tube to a mounting substrate. ### Claim 24 (depends on 1) An illumination assembly comprising a light injector according to claim 1 and an elongated cylindrical light guide having a light guide light input end positioned to receive light emitted from the light output end of the tapered solid light guide. ### Claim 25 (depends on 24) An illumination assembly according to claim 24, wherein the elongated cylindrical light guide and the tapered solid light guide form a unitary element. ### Claim 26 (depends on 10) An illumination assembly comprising a light injector assembly according to claim 10 and an elongated cylindrical light guide having a light guide light input end positioned to receive light emitted from the light output end of the tapered solid light guide. ### Claim 27 (depends on 26) An illumination assembly according to claim 26, wherein the elongated cylindrical light guide and the tapered solid light guide form a unitary element.