# US 8,785,906 B2 · Lamp with controllable spectrum > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,785,906 B2 - Document ID: US8785906B2 - Status: Granted - Kind: B2 - Application number: 11/755,055 - Filed: 2007-05-30 - Published: 2008-12-04 - Granted: 2014-07-22 - Earliest claimed: 2007-05-30 - Assignees: Eastman Kodak Company - Applicants: Michael E. Miller; Paul J. Kane; Ronald S. Cok - Inventors: Michael E. Miller; Paul J. Kane; Ronald S. Cok - Web page: https://patentgrep.com/patent/US8785906B2 ## CPC - C09K 11/025: {non-luminescent particle coatings or suspension media} - C09K 11/883: {with zinc or cadmium} - H10H 20/817: characterised by the crystal structures or orientations, e.g. polycrystalline, amorphous or porous - H10H 20/818: within the light-emitting regions - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS ## Abstract An area illumination inorganic electro-luminescent device including a substrate; and an array of one or more commonly addressed, light-emitting elements. Each commonly-addressed, light-emitting element includes a first electrode layer formed over the substrate, one or more light-emitting layers formed over the first electrode layer and a second electrode layer formed over the light-emitting layer. The light-emitting layers include multiple core/shell quantum dot emitters formed in a common polycrystalline semiconductor matrix, and a number of different core/shell quantum dot emitters emit light with a spectral power distribution having a peak and a FWHM bandwidth, such that the peak wavelengths differ by an amount less than or equal to the average FWHM bandwidth of the different core/shell quantum dot emitters within the range of 460 to 670 nm. ## Claims ### Claim 1 An area illumination inorganic electro-luminescent device with a General Color Rendering Index of 80 or greater, comprising: a. a substrate; b. one or more commonly addressed, light-emitting elements, each commonly-addressed, light-emitting element including: b1) a first electrode layer formed over the substrate, b2) one or more light-emitting layers formed over the first electrode layer, and b3) a second electrode layer formed over the light-emitting layer; c. wherein the one or more light-emitting layers include five or more different distributions of different core/shell quantum dot emitters, each distribution of different core/shell quantum dot emitters emitting a different colored light having a spectral power distribution, each spectral power distribution including a peak wavelength and a FWHM bandwidth and wherein the peak wavelengths of the spectral power distributions of light produced by at least two of the five or more different distributions of different core/shell dot emitters are separated by a distance between the peak wavelengths such that the minimum of the separation distances between any two peak wavelengths of the respective spectral power distributions is less than or equal to 1.1 times the average FWHM bandwidth between 460 and 670 nm, and such that the electro-luminescent device produces white light having a General Color Rendering Index of 80 or greater; and d. wherein the five or more different distributions of different core/shell quantum dot emitters are in a common light-emitting layer. ### Claim 2 (depends on 1) The area illumination inorganic electro-luminescent device of claim 1, wherein each light-emitting layer has the same set of different core/shell quantum dot emitters. ### Claim 3 (depends on 1) The area illumination inorganic electro-luminescent device of claim 1, wherein the spectral power distribution of light produced by each of the different core/shell quantum dot emitters has a FWHM bandwidth of 50 nm or less. ### Claim 4 (depends on 1) The area illumination inorganic electro-luminescent device of claim 1, wherein the spectral power distribution of the device matches a CIE daylight power spectral power distribution. ### Claim 5 (depends on 4) The area illumination inorganic electro-luminescent device of claim 4, wherein the spectral power distribution of the device matches a CIE daylight spectral power distribution, and wherein the light-emitting layer additionally is comprised of at least two additional core/shell quantum dot emitters that emit light having a spectral power distribution with a peak wavelength less than 460 nm and at least one peak wavelength greater than 670 nm. ### Claim 6 (depends on 1) The area illumination inorganic electro-luminescent device of claim 1, wherein the FWHM bandwidth is approximately 30 nm and wherein the light-emitting layer includes 13 or more different core/shell quantum dot emitters which produce light having spectral power distributions with different peak wavelengths. ### Claim 7 (depends on 1) The area illumination inorganic electro-luminescent device of claim 1, wherein the spectral power distribution of the device matches the spectral power distribution of an incandescent lamp. ### Claim 8 (depends on 2) The area illumination inorganic electro-luminescent device of claim 2, wherein the spectral power distribution of the device is designed to match the spectral power distribution of a black body radiator. ### Claim 9 (depends on 3) The area illumination inorganic electro-luminescent device of claim 3, wherein the RMSE between the spectral power distribution of the device and a near blackbody radiator is less than 1×10−3 when this RMSE is calculated between the defined spectral power distribution and the spectral power distribution of a daylight or near blackbody emitters having an equivalent correlated color temperature, and wherein the two spectral power distributions have the same integrated power spectral power between 350 and 750 nm.