# US 2021/0280831 A1 · Light emitting diode and display device including the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0280831 A1 - Document ID: US20210280831A1 - Status: Published application - Kind: A1 - Application number: 17/093,284 - Filed: 2020-11-09 - Published: 2021-09-09 - Earliest claimed: 2020-03-03 - Assignees: Samsung Display Co., Ltd. - Applicants: Samsung Display Co., Ltd. - Inventors: Bora LEE; Hyomin KO - Web page: https://patentgrep.com/patent/US20210280831A1 ## CPC - H10K 50/11: characterised by the electroluminescent [EL] layers - H10K 50/15: Hole transporting layers - H10K 50/156: {comprising a multilayered structure} - H10K 59/879: {comprising refractive means, e.g. lenses} - H10K 59/12: Active-matrix OLED [AMOLED] displays - H10K 59/35: comprising red-green-blue [RGB] subpixels - H10K 59/352: {the areas of the RGB subpixels being different} - H10K 59/353: {characterised by the geometrical arrangement of the RGB subpixels} - H10K 59/80518: {Reflective anodes, e.g. ITO combined with thick metallic layers} - H10K 2101/40: Interrelation of parameters between multiple constituent active layers or sublayers, e.g. HOMO values in adjacent layers - H10K 2102/3026: {Top emission} - H10K 2102/351: {Thickness} - H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES ## Abstract A light emitting diode of an embodiment of the present disclosure includes a first electrode, a hole transport region on an upper portion of the first electrode and having a first refractive index, an emission layer on an upper portion of the hole transport region and having a second refractive index less than the first refractive index, an electron transport region on an upper portion of the emission layer, and a second electrode on an upper portion of the electron transport region. ## Claims ### Claim 1 A light emitting diode comprising: a first electrode; a hole transport region on an upper portion of the first electrode and having a first refractive index; an emission layer on an upper portion of the hole transport region and having a second refractive index less than the first refractive index; an electron transport region on an upper portion of the emission layer; and a second electrode on an upper portion of the electron transport region. ### Claim 2 (depends on 1) The light emitting diode of claim 1, wherein the difference between the first refractive index and the second refractive index is greater than 0.1. ### Claim 3 (depends on 2) The light emitting diode of claim 2, wherein the first refractive index is in a range of 1.7 to 2.2, and the second refractive index is in a range of 1.2 to 1.7. ### Claim 4 (depends on 3) The light emitting diode of claim 3, wherein the emission layer comprises an organic material which has a refractive index of in a range of 1.7 to 2.2 and an organic emitting material. ### Claim 5 (depends on 1) The light emitting diode of claim 1, wherein the emission layer comprises: a first emission layer directly on the hole transport region; and a second emission layer on the first emission layer, wherein the first emission layer has the second refractive index. ### Claim 6 (depends on 5) The light emitting diode of claim 5, wherein the second emission layer has a third refractive index, wherein the third refractive index is equal to or greater than the second refractive index. ### Claim 7 (depends on 6) The light emitting diode of claim 6, wherein the third refractive index is in a range of 1.2 to 2.0. ### Claim 8 (depends on 5) The light emitting diode of claim 5, wherein the thickness ratio of the first emission layer to the second emission layer is in a range of 1:9 to 9:1. ### Claim 9 (depends on 8) The light emitting diode of claim 8, wherein the sum of the thickness of the first emission layer and the thickness of the second emission layer is in a range of 10 nm to 60 nm. ### Claim 10 (depends on 5) The light emitting diode of claim 5, wherein the first emission layer and the second emission layer emit light having the same center wavelength. ### Claim 11 (depends on 1) The light emitting diode of claim 1, wherein the hole transport region comprises: a first hole transport layer directly on a lower portion of the emission layer; and a second hole transport layer on a lower portion of the first hole transport layer, wherein the first hole injection layer has the first refractive index. ### Claim 12 (depends on 1) The light emitting diode of claim 1, wherein the first electrode is a reflective electrode, and the second electrode is a transmissive electrode or a transflective electrode. ### Claim 13 (depends on 1) The light emitting diode of claim 1, further comprising a capping layer on an upper portion of the second electrode. ### Claim 14 A light emitting diode comprising: a first electrode; a hole transport region on an upper portion of the first electrode and having a first refractive index; a first emission layer on an upper portion of the hole transport region and having a second refractive index; a second emission layer on an upper portion of the first emission layer; an electron transport region on an upper portion of the second emission layer; and a second electrode on an upper portion of the electron transport region, wherein the first refractive index is greater than the second refractive index by 0.1 or more. ### Claim 15 (depends on 14) The light emitting diode of claim 14, wherein the first refractive index is in a range of 1.7 to 2.2, and the second refractive index is in a range of 1.2 to 1.7. ### Claim 16 (depends on 14) The light emitting diode of claim 14, wherein the thickness ratio of the first emission layer to the second emission layer is in a range of 1:9 to 9:1. ### Claim 17 (depends on 16) The light emitting diode of claim 16, wherein the sum of the thickness of the first emission layer and the thickness of the second emission layer is in a range of 10 nm to 60 nm. ### Claim 18 A display device comprising a plurality of light emitting diodes, each of the light emitting diodes comprising: a first electrode; a hole transport region on an upper portion of the first electrode and having a first refractive index; an emission layer on an upper portion of the hole transport region and having a second refractive index less than the first refractive index; an electron transport region on an upper portion of the emission layer; and a second electrode on an upper portion of the electron transport region, wherein each of the light emitting diodes emits light having different center wavelengths. ### Claim 19 (depends on 18) The light emitting diode of claim 18, wherein the difference between the first refractive index and the second refractive index is greater than 0.1. ### Claim 20 (depends on 18) The light emitting diode of claim 18, wherein the first electrode is a reflective electrode, and the second electrode is a transmissive electrode or a transflective electrode.