# US 9,964,280 B2 · Apparatus for controlling the re-distribution of light emitted from a light-emitting diode > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,964,280 B2 - Document ID: US9964280B2 - Status: Granted - Kind: B2 - Application number: 15/074,747 - Filed: 2016-03-18 - Published: 2016-07-28 - Granted: 2018-05-08 - Earliest claimed: 2011-06-29 - Assignees: Korry Electronics Co. - Applicants: Korry Electrictronics Co. - Inventors: John R. Green; Stephen H. Humphrey; Timothy R. Robinson - Web page: https://patentgrep.com/patent/US9964280B2 ## CPC - F21V 5/00: Refractors for light sources (characterised by cooling arrangements F21V29/504) - F21K 9/20: Light sources comprising attachment means - F21V 3/02: characterised by the shape - F21V 3/049: {Patterns or structured surfaces for diffusing light, e.g. frosted surfaces} - F21V 19/0055: {by screwing} - F21V 29/70: characterised by passive heat-dissipating elements, e.g. heat-sinks - G02B 5/0242: {by means of dispersed particles} - G02B 5/0278: {used in transmission} - G02B 5/0294: {adapted to provide an additional optical effect, e.g. anti-reflection or filter} - F21V 29/89: Metals - F21Y 2115/10: Light-emitting diodes [LED] - F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR - 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 - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED ## Abstract A system for re-distributing light emitted from a light source using an optical element is described. The optical element is manufactured using a bulk matrix material, and diffusing particles and/or scattering particles are embedded within the bulk material. The optical element is coupled to the light source to capture emitted light and redistribute the light in a desired angular distribution pattern depending on the ratio of total weight of diffusing particles to total weight of scattering particles. ## Claims ### Claim 1 An illumination system comprising: an illumination source configured to emit light in forward directions away from the illumination source; and an optical element coupled to the illumination source and configured to receive the emitted light, the optical element comprising a material embedded with forward-scattering particles with negligible light absorption that redirects a first portion of the light forwardly away from the illumination source, and backward-scattering particles with negligible light absorption and that redirect a second portion of the light rearwardly toward and past the illumination source, wherein the redirected first and second portions of the light are angularly distributed in a substantially quasi-isotropic light distribution relative to the illumination source, wherein at least a portion of the quasi-isotropic light distribution is rearward of the illumination source. ### Claim 2 (depends on 1) The illumination system of claim 1, wherein the material of the optical element has a first index of refraction, the forward-scattering particles have a second index of refraction, and the backward-scattering particles have a third index of refraction, wherein a difference between the first and second indices of refraction is less than a difference between the first and third indices of refraction. ### Claim 3 (depends on 1) The illumination system of claim 1, wherein the forward-scattering particles are embedded throughout the material at a first substantially uniform density and wherein the backward-scattering particles are embedded throughout the material at a second substantially uniform density, the first uniform density different from the second uniform density. ### Claim 4 (depends on 1) The illumination system of claim 1, wherein the light emitted from the illumination source has a first angular distribution pattern, and wherein the optical element is configured to receive the emitted light and to emit light having a second angular distribution pattern different from the first. ### Claim 5 (depends on 4) The illumination system of claim 4, wherein the second angular distribution pattern is substantially uniform over an outer surface of the optical element. ### Claim 6 (depends on 1) The illumination system of claim 1, wherein the optical element has a semi-spherical outer surface. ### Claim 7 (depends on 1) The illumination system of claim 1, wherein the material of the optical element comprises at least one of: a polymer, glass, crystal, and foam. ### Claim 8 A light-redirecting optical element, comprising: a bulk material configured to receive light emitted from a source in forward directions having a first angular distribution pattern and to redistribute the received light in a second angular distribution pattern; a plurality of forward-scattering particles with negligible light absorption embedded in the bulk material and configured to redirect a first portion of the light forwardly away from the illumination source; and a plurality of backward-scattering particles with negligible light absorption embedded in the bulk material and configured to redirect a second portion of the light rearwardly toward and past the illumination source; wherein the redirected first and second portions of the light are angularly distributed in a substantially quasi-isotropic light distribution relative to the illumination source; wherein at least a portion of the quasi-isotropic light distribution is rearward of the illumination source. ### Claim 9 (depends on 8) The light-redirecting optical element of claim 8, wherein the bulk material has a first index of refraction, the forward-scattering particles have a second index of refraction, and the backward-scattering particles have a third index of refraction, wherein a difference between the first and second indices of refraction is less than a difference between the first and third indices of refraction. ### Claim 10 (depends on 8) The light-redirecting optical element of claim 8, wherein the second angular distribution pattern is wider than the first angular distribution pattern. ### Claim 11 (depends on 8) The light-redirecting optical element of claim 8, wherein the forward-scattering particles are embedded throughout the bulk material at a first substantially uniform density and wherein the backward-scattering particles are embedded throughout the bulk material at a second substantially uniform density, the first uniform density different from the second uniform density. ### Claim 12 (depends on 8) The light-redirecting optical element of claim 8, wherein, the optical element has a semi-spherical outer surface. ### Claim 13 (depends on 8) The light-redirecting optical element of claim 8, wherein the ratio of forward-scattering particles to backward-scattering particles is at least 70:1. ### Claim 14 A method of changing a distribution of emitted light from a source, comprising: emitting light from a light-emitting diode (LED) in forward directions away from the LED; receiving the emitted light with an optical element, wherein the optical element comprises a bulk material embedded with a plurality of forward-scattering particles and a plurality of backward-scattering particles; re-emitting at least some of the received light in a distribution pattern, wherein at least a first portion of light incident on the plurality of forward scattering particles is re-emitted with negligible light absorption in the forward direction away from the LED and wherein at least a second portion of light incident on the plurality of backward-scattering particles is re-emitted with negligible light absorption in a backward direction toward and past the illumination source; wherein the re-emitted first and second portions of the light are angularly distributed in a substantially quasi-isotropic light distribution relative to the illumination source; wherein at least a portion of the quasi-isotropic light distribution is rearward of the illumination source. ### Claim 15 (depends on 14) The method of claim 14, wherein the distribution pattern of the re-emitted light is substantially uniform over a surface of the optical element. ### Claim 16 (depends on 14) The method of claim 14, wherein the bulk material has a first index of refraction, the forward-scattering particles have a second index of refraction, and the backward-scattering particles have a third index of refraction, wherein a difference between the first and second indices of refraction is less than a difference between the first and third indices of refraction. ### Claim 17 (depends on 14) The method of claim 14, wherein the forward-scattering particles are embedded throughout the bulk material at a first substantially uniform density and the backward-scattering particles are embedded throughout the bulk material at a second substantially uniform density different from the first. ### Claim 18 (depends on 14) The method of claim 14, wherein the optical element has a semi-spherical surface. ### Claim 19 (depends on 14) The method of claim 14, wherein the ratio of forward-scattering particles to backward-scattering particles is at least 70:1.