# US 10,121,420 B2 · Display device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,121,420 B2 - Document ID: US10121420B2 - Status: Granted - Kind: B2 - Application number: 15/421,554 - Filed: 2017-02-01 - Published: 2017-09-07 - Granted: 2018-11-06 - Earliest claimed: 2016-03-01 - Assignees: Japan Display Inc. - Applicants: Japan Display Inc. - Inventors: Hirofumi Kato - Web page: https://patentgrep.com/patent/US10121420B2 ## CPC - G09G 3/3426: {the different display panel areas being distributed in two dimensions, e.g. matrix} - G02B 6/0041: {provided in the bulk of the light guide} - G02F 1/1326: {Liquid crystal optical waveguides or liquid crystal cells specially adapted for gating or modulating between optical waveguides} - G02F 1/1334: based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals - G02F 1/133615: {Edge-illuminating devices, i.e. illuminating from the side} - G02F 1/134309: {characterised by their geometrical arrangement} - G02F 1/137: characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering - G09G 3/342: {using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines} - G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)} - G02F 1/13756: {the liquid crystal selectively assuming a light-scattering state (G02F1/1334, G02F1/13718 take precedence)} - G09G 2310/024: Scrolling of light from the illumination source over the display in combination with the scanning of the display screen - G09G 2320/0646: Modulation of illumination source brightness and image signal correlated to each other - G09G 2360/121: using a cache memory - G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) - 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 In a display device, an image display panel updates an image in a frame cycle including an image scanning period and a vertical blanking period, a light modulation layer is disposed at a back of the panel and switched to a scattering or transmission state depending on an electric field applied, a light source emits light which enters the light modulation layer from its side and travels therethrough, electrodes are formed according to divided areas of the light modulation layer arranged in a direction of the light and apply the electric field to the light modulation layer, and a controller drives the electrodes in synchronization with image scanning to switch the divided areas to the scattering state in order during the image scanning period, and drives the electrodes according to distances from the side to control the scattering state on the individual divided areas during the vertical blanking period. ## Claims ### Claim 1 A display device comprising: an image display panel which updates an image in a frame cycle including an image scanning period and a vertical blanking period; a light modulation layer disposed at a back of the image display panel and switched to a scattering state in which incident light is scattered or a transmission state in which the incident light is transmitted according to an electric field applied; a light source which emits light that enters the light modulation layer from a side thereof and travels in the light modulation layer; electrodes which are formed according to divided areas of the light modulation layer arranged in a direction in which the light from the light source travels and which apply the electric field to the light modulation layer; and a controller which drives the electrodes in synchronization with image scanning and switches in order the divided areas to be put into the scattering state, during a first period corresponding to the image scanning period, and which drives the electrodes according to distances from the side to control the scattering state according to the divided areas, during a second period corresponding to the vertical blanking period. ### Claim 2 (depends on 1) The display device according to claim 1, wherein the controller puts the divided areas into the scattering state in an order in which the image display panel ends the image scanning. ### Claim 3 (depends on 1) The display device according to claim 1, wherein the controller controls scattering time for which the divided areas are put into the scattering state during the second period on the basis of amounts of decreases in luminances of the light from the light source which enters the light modulation layer from the side corresponding to distances to the divided areas. ### Claim 4 (depends on 1) The display device according to claim 1, wherein the controller controls scattering time according to deficiencies when luminances of light emitted from the divided areas in the first period do not reach required luminances on the basis of luminance distribution tables in which luminances of light emitted from the divided areas when the divided areas are put into the scattering state under same drive conditions are registered. ### Claim 5 (depends on 1) The display device according to claim 1 further comprising a second light source which emits light that enters the light modulation layer from a second side opposite a first side from which the light from the light source enters the light modulation layer and traveling in the light modulation layer, wherein the controller controls the scattering state in the divided areas on the basis of distances between the divided areas and the first side and distances between the divided areas and the second side.