# US 2019/0171066 A1 · Backlight unit 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 2019/0171066 A1 - Document ID: US20190171066A1 - Status: Published application - Kind: A1 - Application number: 16/208,444 - Filed: 2018-12-03 - Published: 2019-06-06 - Earliest claimed: 2017-12-06 - Assignees: LG Display Co., Ltd. - Applicants: LG Display Co., Ltd. - Inventors: KiDuck PARK - Web page: https://patentgrep.com/patent/US20190171066A1 ## CPC - G02F 1/133608: {including particular frames or supporting means} - B29D 11/00326: {having particular surface properties, e.g. a micropattern} - G02F 1/133308: {Support structures for LCD panels, e.g. frames or bezels} - G02F 1/133603: {with LEDs} - G02F 1/133606: {including a specially adapted diffusing, scattering or light controlling members} - G02F 1/133611: {including means for improving the brightness uniformity} - B29D 11/0073: {Optical laminates} - B29D 11/00798: {Producing diffusers} - G02F 1/133322: {Mechanical guidance or alignment of LCD panel support components} - G02F 1/133607: {the light controlling member including light directing or refracting elements, e.g. prisms or lenses} - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00) ## Abstract Disclosed are a backlight unit and a display device including the same. The backlight unit and display device can minimize a change in an optical layer when exposed to hostile environments, such as high and low temperature environments. The backlight unit and the display device have a rigid structure, due to the minimized change in the optical layer even when exposed to hostile environments, such as high and low temperature environments. ## Claims ### Claim 1 A backlight unit comprising: a plurality of light sources emitting light; and an optical sheet layer including a first optical sheet and a second optical sheet bonded with each other and provided on a path of light exiting from the plurality of light sources, wherein the light exited from the light sources enters the first optical sheet; the second optical sheet is disposed on the first optical sheet, and the light exited from the first optical sheet enters the second optical sheet, and a void present in a plurality of first recesses depressed inwardly from one surface of the first optical sheet or the second optical sheet, at a bonding area between the first optical sheet and the second optical sheet. ### Claim 2 (depends on 1) The backlight unit according to claim 1, wherein the optical sheet layer further comprises a third optical sheet bonded to a bottom surface of the first optical sheet or a top surface of the second optical sheet. ### Claim 3 (depends on 1) The backlight unit according to claim 1, wherein the optical sheet layer further comprises a third optical sheet bonded to a top surface of the second optical sheet, and a void is present in a plurality of second recesses depressed inwardly from one surface of the second optical sheet or the third optical sheet, at a bonding area between the second optical sheet and the third sheet. ### Claim 4 (depends on 1) The backlight unit according to claim 1, wherein the plurality of first recesses are arranged at a same distance. ### Claim 5 (depends on 3) The backlight unit according to claim 3, wherein the plurality of first recesses and the plurality of second recesses are arranged at a same distance, and the distance between the plurality of first recesses differs from the distance between the plurality of second recesses. ### Claim 6 (depends on 5) The backlight unit according to claim 5, wherein the distance between the plurality of first recesses are greater than the distance between the plurality of second recesses. ### Claim 7 (depends on 3) The backlight unit according to claim 3, wherein the plurality of first recesses has a depth different from a depth of the plurality of second recesses. ### Claim 8 (depends on 7) The backlight unit according to claim 7, wherein the depth of the plurality of first recesses are greater than the depth of the plurality of second recesses. ### Claim 9 (depends on 3) The backlight unit according to claim 3, wherein the plurality of first recesses and the plurality of second recesses are arranged to partially overlap each other while being parallel to each other. ### Claim 10 (depends on 3) The backlight unit according to claim 3, wherein horizontal surfaces are provided between adjacent recesses among the plurality of first recesses and between adjacent recesses among the plurality of second recesses. ### Claim 11 (depends on 10) The backlight unit according to claim 10, further comprising a bonding material layer on the plurality of first recesses and the plurality of second recesses, wherein a thickness of the bonding material layer on the horizontal surfaces between the plurality of first recesses and the horizontal surfaces between the plurality of second recesses is greater than a thickness of the bonding material layer in the plurality of first recesses and the plurality of second recesses. ### Claim 12 (depends on 1) The backlight unit according to claim 1, further comprising: a diffuser plate disposed above the optical sheet layer and made of a transparent glass material; and a luminance enhancement film disposed above the diffuser plate, wherein a bottom surface of the diffuser plate is bonded to a top surface of the optical sheet layer. ### Claim 13 (depends on 1) The backlight unit according to claim 1, wherein at least one surface of a top surface and a bottom surface of the optical sheet layer includes a plurality of light-diffusing particles. ### Claim 14 A display device comprising: a cover bottom; a plurality of light sources disposed above the cover bottom and emitting light; an optical sheet layer including a first optical sheet and a second optical sheet bonded with each other and disposed above the plurality of light sources; a display panel disposed above the optical sheet layer; and a guide panel disposed outside the cover bottom and supporting a bottom portion of the optical sheet layer and a bottom portion of the display panel, wherein the light exited from the light sources enters the first optical sheet; and the second optical sheet disposed on the first optical sheet, wherein the light exited from the first optical sheet enters the second optical sheet; and a void present in a plurality of first recesses depressed inwardly from one surface of the first optical sheet or the second optical sheet, at a bonding area between the first optical sheet and the second optical sheet. ### Claim 15 (depends on 14) The display device according to claim 14, wherein the optical sheet layer further comprises a third optical sheet bonded to a top surface of the second optical sheet, and a void is present in a plurality of second recesses depressed inwardly from one surface of the second optical sheet or the third optical sheet, at a bonding area between the second optical sheet and the third sheet. ### Claim 16 (depends on 15) The display device according to claim 15, wherein the plurality of first recesses and the plurality of second recesses are arranged at a same distance. ### Claim 17 (depends on 15) The display device according to claim 15, further comprising: a diffuser plate disposed above the optical sheet layer and made of a transparent glass material; and a luminance enhancement film disposed above the diffuser plate, wherein a bottom surface of the diffuser plate is bonded to a top surface of the optical sheet layer. ### Claim 18 (depends on 17) The display device according to claim 17, wherein at least one surface of a top surface and a bottom surface of the optical sheet layer includes a plurality of light-diffusing particles. ### Claim 19 A backlight unit comprising: a plurality of light sources emitting light; an optical sheet layer including first and second optical sheets bonded with each other and disposed on a path of light exiting from the plurality of light sources; and a diffuser plate disposed on the optical sheet layer, wherein the light exited from the light sources enters the first optical sheet, the second optical sheet is disposed on the first optical sheet, and the light exited from the first optical sheet enters the second optical sheet; and the first optical sheet or the second optical sheet has a surface with a plurality of first recesses depressed inwardly at a same distance. ### Claim 20 (depends on 19) The backlight unit according to claim 19, further comprising a luminance enhancement film disposed on the diffuser plate, so that the diffuser plate is disposed between luminance enhancement film and the optical sheet layer.