# US 9,753,213 B2 · Planar light source device and liquid crystal display apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,753,213 B2 - Document ID: US9753213B2 - Status: Granted - Kind: B2 - Application number: 14/418,850 - Filed: 2013-07-24 - Published: 2015-10-22 - Granted: 2017-09-05 - Earliest claimed: 2012-07-31 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Rena Nishitani; Nami Nakano; Tomohiro Sasagawa; Nobutaka Kobayashi - Web page: https://patentgrep.com/patent/US9753213B2 ## CPC - G02B 6/0068: {Arrangements of plural sources, e.g. multi-colour light sources} - G02B 6/0031: {Reflecting element, sheet or layer} - G02B 6/0078: {Side-by-side arrangements, e.g. for large area displays} - G02B 6/0096: {the lights guides being of the hollow type} - G02B 6/0073: {Light emitting diode [LED]} - G02F 1/133601: {for spatial active dimming} - G02F 1/133615: {Edge-illuminating devices, i.e. illuminating from the side} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - 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 ## Abstract A planar light source device 200 includes a light source 10 and a reflection member 30. The light source 10 emits a light beam 10a having directivity. The reflection member 30 has a box shape including a single bottom-plate part 30e, side-plate parts 30a, 30b, 30c and 30d connected to the bottom-plate part 30e, and an opening part 30f facing the bottom-plate part 30e. The box shape has inner surfaces which are reflection surfaces. The bottom-plate part 30e has a quadrilateral shape including two facing short sides and two facing long sides. The light beam 10a enters an inside of the box shape of the reflection member 30 through a side of the side-plate part 30a connected to the short side of the bottom-plate part 30e, travels in a direction of the long side of the bottom-plate part 30e while being reflected at the side-plate parts 30c and 30d connected to the long sides of the bottom-plate part 30e, and is emitted through the opening part 30f. The reflection surfaces of the side-plate parts 30c and 30d connected to the long sides of the bottom-plate part 30e include regions at which the light beam 10a is specularly reflected and regions at which the light beam 10a is diffused and reflected. ## Claims ### Claim 1 A planar light source device comprising: a first light source that emits a first light beam having directivity; a reflection member including a single bottom-plate part, an opening part facing the bottom-plate part, and side-plate parts delimiting a space between the bottom-plate part and the opening part so that the space has a columnar shape, wherein the side-plate parts are disposed on positions of respective sides of the bottom-plate part, the bottom-plate part and the side-plate parts having inner surfaces which are reflection surfaces, and a second light source that emits a second light beam having a divergence angle wider than that of the first light beam, wherein the opening part has a quadrilateral shape including two facing short sides and two facing long sides; the quadrilateral shape being formed by the side-plate parts, wherein the first light beam enters an inside of the reflection member through a side of a first side-plate part which is one of the side-plate parts disposed on positions of the short sides of the opening part, travels in a direction of the long sides while being reflected at second side-plate parts which are the side-plate parts disposed on positions of the long sides of the opening part, and is emitted through the opening part; wherein the reflection surface of the second side-plate part includes a region at which the first light beam is spectrally reflected and a region at which the first light beam is diffused and reflected, such that a density of a diffusion reflection material of the reflection surface of the second side-plate part increases in the traveling direction of the first light beam; and wherein the second light beam enters the inside of the reflection member through a side of the second side-plate part or a side of the bottom-plate part, and is emitted through the opening part. ### Claim 2 (depends on 1) The planar light source device according to claim 1, wherein the reflection surface of the first side-plate part is inclined so as to face the opening part side. ### Claim 3 (depends on 2) The planar light source device according to claim 2, comprising a plurality of the reflection members, wherein the plurality of the reflection members are arranged in a direction of the short sides so that the first side-plate parts of adjacent reflection members of the plurality of the reflection members are adjacent to each other. ### Claim 4 (depends on 1) The planar light source device according to claim 1, comprising a plurality of the reflection members, wherein the plurality of the reflection members are arranged in a direction of the short sides so that the first side-plate parts of adjacent reflection members of the plurality of the reflection members are adjacent to each other. ### Claim 5 (depends on 4) The planar light source device according to claim 4, wherein the second light source includes an LED element. ### Claim 6 (depends on 1) The planar light source device according to claim 1, wherein the second light source includes an LED element. ### Claim 7 (depends on 1) A liquid crystal display apparatus comprising: the planar light source device according to claim 1, and a liquid crystal display element that receives light emitted by the planar light source device, and emits image light, wherein the first light source is disposed on a lower end side of the planar light source device. ### Claim 8 (depends on 1) The planar light source device according to claim 1, comprising a plurality of the reflection members, wherein the plurality of the reflection members are arranged in a direction of the short sides so that the first side-plate parts of adjacent reflection members of the plurality of the reflection members are adjacent to each other. ### Claim 9 (depends on 8) The planar light source device according to claim 8, wherein the second light source includes an LED element. ### Claim 10 (depends on 1) The planar light source device according to claim 1, wherein the second light source includes an LED element. ### Claim 11 A planar light source device comprising: a first light source that emits a first light beam; a reflection member having a single bottom-plate part, an opening part facing the bottom-plate part, and side-plate parts delimiting a space between the bottom-plate part and the opening part so that the space has a columnar shape, wherein the side-plate parts are disposed on positions of respective sides of the bottom-plate part, the bottom-plate part and the side-plate parts having inner surfaces which are reflection surfaces, and wherein the first light source includes a laser element that emits the first light beam; wherein the opening part has a quadrilateral shape including two facing short sides and two facing long sides, the quadrilateral shape being formed by the side-plate parts; wherein the first light beam enters an inside of the reflection member through a side of a first side-plate part which is one of the side-plate parts disposed on positions of the short sides of the opening part, travels in a direction of the long sides while being reflected alternately at two second side-plate parts which are the side-plate parts disposed on positions of the long sides of the opening part, and is emitted through the opening part, and wherein the reflection surface of the second side-plate part includes a region at which the first light beam is spectrally reflected and a region at which the first light beam is diffused and reflected, such that a density of a diffusion reflection material of the reflection surface of the second side-plate part increases in the traveling direction of the first light beam. ### Claim 12 (depends on 11) The planar light source device according to claim 11, wherein the reflection surface of the first side-plate part is inclined so as to face the opening part side. ### Claim 13 (depends on 12) The planar light source device according to claim 12, comprising a plurality of the reflection members, wherein the plurality of the reflection members are arranged in a direction of the short sides so that the first side-plate parts of adjacent reflection members of the plurality of the reflection members are adjacent to each other. ### Claim 14 (depends on 11) The planar light source device according to claim 11, comprising a plurality of the reflection members, wherein the plurality of the reflection members are arranged in a direction of the short sides so that the first side-plate parts of adjacent reflection members of the plurality of the reflection members are adjacent to each other. ### Claim 15 (depends on 11) A liquid crystal display apparatus comprising: the planar light source device according to claim 11, and a liquid crystal display element that receives light emitted by the planar light source device, and emits image light, wherein the first light source is disposed on a lower end side of the planar light source device. ### Claim 16 (depends on 11) The planar light source device according to claim 11, comprising a plurality of the reflection members, wherein the plurality of the reflection members are arranged in a direction of the short sides so that the first side-plate parts of adjacent reflection members of the plurality of the reflection members are adjacent to each other.