# US 9,518,718 B2 · Bandpass filter for use in light emitting device and light emitting device using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,518,718 B2 - Document ID: US9518718B2 - Status: Granted - Kind: B2 - Application number: 14/140,379 - Filed: 2013-12-24 - Published: 2014-07-03 - Granted: 2016-12-13 - Earliest claimed: 2012-12-28 - Assignees: Nichia Corporation - Applicants: Nichia Corporation - Inventors: Daisuke Sanga; Tomonori Morizumi; Naoki Azuma; Keisuke Sejiki; Kunihito Sugimoto - Web page: https://patentgrep.com/patent/US9518718B2 ## CPC - F21V 9/08: for producing coloured light, e.g. monochromatic; for reducing intensity of light (with provision for controlling the colour F21V9/40) - G02B 5/285: {comprising deposited thin solid films (G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361)} - H10H 20/855: Optical field-shaping means, e.g. lenses - H10W 90/00: Package configurations - H10H 20/851: Wavelength conversion means - H10W 90/724: {between a chip and a stacked insulating package substrate, interposer or RDL} - F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract Provided is a bandpass filter for a light emitting device that can improve the light emission efficiency in use for a light emitting device, and a light emitting device that can obtain the high light emission efficiency by using the bandpass filter. The light emitting device includes a substrate; a light emitting element disposed over the substrate; a phosphor-containing layer containing at least one kind of phosphor; and a bandpass filter disposed over a surface of the phosphor-containing layer on the light emitting element side, the bandpass filter including a multilayer film having a plurality of first and second dielectric layers, the second dielectric layer being disposed over the first dielectric layer. The bandpass filter has a transmittance of 60% or more for light having a light emission peak wavelength of the light emitting element at an incident angle of 0 to 85°, and another transmittance of 40% or less for light having a light emission peak wavelength of at least one kind of phosphor at an incident angle of a Brewster's angle (θb)+5° (θb+5°) to 85° of the bandpass filter. ## Claims ### Claim 1 A light emitting device, comprising: a substrate; a resin package disposed on the substrate, the resin package comprising a light-reflective resin; a light emitting element that is laterally surrounded by the resin package such that the resin package contacts lateral surfaces of the light emitting element; a phosphor-containing layer containing at least one kind of phosphor; and a bandpass filter disposed between the phosphor-containing layer and the light emitting element, wherein the bandpass filter is laterally surrounded by the resin package such that the resin package contacts lateral surfaces of the bandpass filter, and wherein the bandpass filter comprises a multilayer film including a plurality of first and second dielectric layers, the second dielectric layer being disposed over the first dielectric layer, wherein the bandpass filter has a transmittance of 60% or more for light having a light emission peak wavelength of the light emitting element at an incident angle in a range of 0 to 85° , and wherein the bandpass filter has a transmittance of 40% or less for light having a light emission peak wavelength of the at least one kind of phosphor at an incident angle in a range of a Brewster's angle (θb) of the bandpass filter +5°(θb +5°) to 85°. ### Claim 2 (depends on 1) The light emitting device according to claim 1, wherein the bandpass filter has a transmittance of 60% or less for light having a light emission peak wavelength of the at least one kind of phosphor at an incident angle that is the same angle as the Brewster's angle (θb) of the bandpass filter. ### Claim 3 (depends on 1) The light emitting device according to claim 1, wherein the bandpass filter has a transmittance of 50% or less for light having a light emission peak wavelength of the at least one kind of phosphor at an incident angle in a range of a Brewster's angle (θb) of the bandpass filter −5°(θb −5°) to 45°. ### Claim 4 (depends on 2) The light emitting device according to claim 2, wherein the bandpass filter has a transmittance of 50% or less for light having a light emission peak wavelength of the at least one kind of phosphor at an incident angle in a range of a Brewster's angle (θb) of the bandpass filter −5°(θb−5°) to 45°. ### Claim 5 (depends on 1) The light emitting device according to claim 1, wherein the light emitting element is a blue light emitting diode. ### Claim 6 (depends on 4) The light emitting device according to claim 4, wherein the light emitting element is a blue light emitting diode. ### Claim 7 (depends on 1) The light emitting device according to claim 1, wherein at least one kind of the phosphor is an yttrium aluminum garnet phosphor. ### Claim 8 (depends on 4) The light emitting device according to claim 4, wherein at least one kind of the phosphor is an yttrium aluminum garnet phosphor. ### Claim 9 (depends on 6) The light emitting device according to claim 6, wherein at least one kind of the phosphor is an yttrium aluminum garnet phosphor. ### Claim 10 (depends on 1) The light emitting device according to claim 1, wherein a thickness of a first layer of the bandpass filter, on a phosphor side of the multilayer film, is larger than that of each of other layers of the multilayer film. ### Claim 11 (depends on 2) The light emitting device according to claim 2, wherein a thickness of a first layer of the bandpass filter, on a phosphor side of the multilayer film, is larger than that of each of other layers of the multilayer film. ### Claim 12 (depends on 3) The light emitting device according to claim 3, wherein a thickness of a first layer of the bandpass filter, on a phosphor side of the multilayer film, is larger than that of each of other layers of the multilayer film. ### Claim 13 (depends on 4) The light emitting device according to claim 4, wherein a thickness of a first layer of the bandpass filter, on a phosphor side of the multilayer film, is larger than that of each of other layers of the multilayer film. ### Claim 14 (depends on 6) The light emitting device according to claim 6, wherein wherein a thickness of a first layer of the bandpass filter, on a phosphor side of the multilayer film, is larger than that of each of other layers of the multilayer film. ### Claim 15 (depends on 8) The light emitting device according to claim 8, wherein wherein a thickness of a first layer of the bandpass filter, on a phosphor side of the multilayer film, is larger than that of each of other layers of the multilayer film. ### Claim 16 (depends on 9) The light emitting device according to claim 9, wherein wherein a thickness of a first layer of the bandpass filter, on a phosphor side of the multilayer film, is larger than that of each of other layers of the multilayer film. ### Claim 17 (depends on 10) The light emitting device according to claim 10, wherein the bandpass filter has a transmittance of 60% or less for light having a wavelength in a range of 520 to 580 nm at an incident angle that is the same as the Brewster's angle (θb). ### Claim 18 (depends on 6) The light emitting device according to claim 6, wherein the bandpass filter has a transmittance of 50% or less for light having a wavelength in a range of 520 to 580 nm at an incident angle in a range of the Brewster's angle (θb) −5°(θb −5°) to 45°. ### Claim 19 (depends on 1) The light emitting device according to claim 1, further comprises a contact layer disposed between the bandpass filter and the light emitting element. ### Claim 20 (depends on 19) The light emitting device according to claim 19, wherein the contact layer is thinner than the bandpass filter. ### Claim 21 (depends on 19) The light emitting device according to claim 19, wherein the contact layer is laterally surrounded by the resin package such that the resin package contacts side surfaces of the contact layer.