# US 10,373,568 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 10,373,568 B2 - Document ID: US10373568B2 - Status: Granted - Kind: B2 - Application number: 15/088,119 - Filed: 2016-04-01 - Published: 2016-10-06 - Granted: 2019-08-06 - Earliest claimed: 2015-04-02 - Assignees: Funai Electric Co., Ltd. - Applicants: Funai Electric Co., Ltd. - Inventors: Hiroshi Yamashita; Tatsuya Kita - Web page: https://patentgrep.com/patent/US10373568B2 ## CPC - H05B 45/3725: Switched mode power supply [SMPS] - G09G 3/3406: {Control of illumination source (illumination devices structurally associated with liquid crystal cells G02F1/1336)} - G09G 3/342: {using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines} - H05B 45/12: using optical feedback - G09G 3/3611: {Control of matrices with row and column drivers} - G09G 2310/0237: Switching ON and OFF the backlight within one frame - G09G 2310/024: Scrolling of light from the illumination source over the display in combination with the scanning of the display screen - G09G 2320/0252: Improving the response speed - G09G 2320/0257: Reduction of after-image effects - G09G 2320/0261: in the context of movement of objects on the screen or movement of the observer relative to the screen - G09G 2320/0633: by amplitude modulation of the brightness of the illumination source - G09G 2320/064: by time modulation of the brightness of the illumination source - G09G 2330/021: Power management, e.g. power saving - G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - 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) ## Abstract A liquid crystal display device includes a liquid crystal panel, a backlight panel and a backlight drive circuit which outputs drive current of the backlights, the duty ratio and the amplitude of which are changeable. The backlight drive circuit outputs the drive current based on duty ratio characteristics that the duty ratio is greater as the luminance of the backlights is higher and amplitude characteristics that is divided with a predetermined luminance as a boundary into the first and second regions, and that the change rate of the amplitude of the drive current with respect to the luminance is less than or equal to the predetermined change rate in the first region, and the change rate of the amplitude of the drive current with respect to the luminance is greater than the predetermined change rate. ## Claims ### Claim 1 A display device comprising: a display; a light source; and a controller that controls output of a drive current to the light source based on duty ratio characteristics and amplitude characteristics corresponding to a luminance of the light source, wherein the amplitude characteristics are divided with a predetermined luminance of the light source as a boundary, into a first region that is less than or equal to the predetermined luminance, and a second region that is higher than the predetermined luminance, and a change rate of, an amplitude of the drive current with respect to the luminance of the light source is less than or equal to a predetermined change rate in the first region, and a change rate of the amplitude of the drive current in the second region differs from a change rate of the amplitude of the drive current in the first region, wherein the change rate of the amplitude of the drive current in the second region gradually increases as the luminance of the light source increases. ### Claim 2 (depends on 1) The display device according to claim 1, wherein the first region of the amplitude characteristics is indicated as a straight line or a curved line. ### Claim 3 (depends on 1) The display device according to claim 1, wherein the change rate of the amplitude of the drive current with respect to the luminance of the light source is greater than the predetermined change rate in the second region of the amplitude characteristics. ### Claim 4 (depends on 1) The display device according to claim 1, wherein the second region of the amplitude characteristics is indicated as a straight line or a curved line. ### Claim 5 (depends on 1) The display device according to claim 1, wherein a range of a luminance of the first region is greater than or equal to a range of a luminance of the second region. ### Claim 6 (depends on 1) The display device according to claim 1, wherein in the first region, the amplitude of the drive current with respect to a first luminance of the light source is greater than the amplitude of the drive current with respect to a second luminance that is higher than the first luminance. ### Claim 7 (depends on 1) The display device according to claim 1, wherein in the first region, the amplitude of the drive current with respect to a first luminance of the light source is substantially equal to the amplitude of the drive current with respect to a second luminance that is higher than the first luminance. ### Claim 8 (depends on 1) The display device according to claim 1, wherein in the second region, the amplitude of the drive current with respect to a third luminance of the light source is greater than the amplitude of the drive current with respect to a fourth luminance that is higher than the third luminance. ### Claim 9 (depends on 1) The display device according to claim 1, wherein the duty ratio characteristics indicate a greater duty ratio as the luminance of the light source is higher. ### Claim 10 (depends on 1) The display device according to of claim 1, wherein the duty ratio characteristics are divided with the predetermined luminance as a boundary, into a third region that is less than or equal to the predetermined luminance, and a fourth region that is higher than the predetermined luminance, and a change rate of the duty ratio of the drive current with respect to the luminance of the light source in the third region is smaller than a change rate of the duty ratio of the drive current with respect to the luminance of the light source in the fourth region. ### Claim 11 (depends on 10) The display device according to claim 10, wherein in the third region, the duty ratio of the drive current with respect to a fifth luminance of the light source is smaller than the duty ratio of the drive current with respect to a sixth luminance that is higher than the fifth luminance. ### Claim 12 (depends on 10) The display device according to claim 10, wherein in the fourth region, the duty ratio of the drive current with respect to a seventh luminance of the light source is smaller than the duty ratio of the drive current with respect to an eighth luminance that is higher than the seventh luminance. ### Claim 13 (depends on 1) The display device according to claim 1, wherein the duty ratio of the drive current at the predetermined luminance is configured based on a response speed of the display. ### Claim 14 (depends on 13) The display device according to claim 13, wherein the duty ratio of the drive current at the predetermined luminance is substantially equal to a ratio of a period in which a transmittance of the display is at a predetermined transmittance over a vertical scan period. ### Claim 15 A display device that drives a light source based on amplitude characteristics that are divided with a predetermined luminance as a boundary, into a first region that is less than or equal to the predetermined luminance, and a second region that is higher than the predetermined luminance, wherein the amplitude characteristic in the first region is indicated as a straight line or a curved line, and the amplitude characteristic in the second region is indicated as a curved line that has a different change rate from the first region, wherein the amplitude characteristic corresponds to a drive current of the light source, wherein the change rate of the amplitude of the drive current in the second region gradually increases as the luminance of the light source increases. ### Claim 16 (depends on 15) The display device according to claim 15, wherein a range of a luminance in the first region is greater than or equal to a range of a luminance in the second region. ### Claim 17 (depends on 15) The display device according to claim 15, wherein in the first region, the amplitude of the drive current with respect to a first luminance of the light source is greater than the amplitude of the drive current with respect to a second luminance that is higher than the first luminance. ### Claim 18 (depends on 15) The display device according to claim 15, wherein in the first region, the amplitude of the drive current with respect to a first luminance of the light source is substantially equal to the amplitude of the drive current with respect to a second luminance that is higher than the first luminance. ### Claim 19 (depends on 15) The display device according to claim 15, wherein in the second region, the amplitude of the drive current with respect to a third luminance of the light source is greater than the amplitude of the drive current with respect to a fourth luminance that is higher than the third luminance. ### Claim 20 (depends on 15) The display device according to claim 15, wherein the light source is, further, driven based on a duty ratio characteristics, and the duty ratio characteristics is divided with the predetermined luminance as a boundary, into a third region that is less than or equal to the predetermined luminance, and a fourth region that is higher than the predetermined luminance wherein the duty ratio characteristic in the third region is indicated as a straight line or a curved line, and the duty ratio characteristic in the fourth region is indicated as a straight line or a curved line that has a greater change rate than the third region. ### Claim 21 (depends on 20) The display device according to claim 20, wherein in the third region, the duty ratio of the drive current with respect to a fifth luminance is smaller than the duty ratio of the drive current with respect to a sixth luminance that is higher than the fifth luminance. ### Claim 22 (depends on 20) The display device according to claim 20, wherein in the fourth region, the duty ratio of the drive current with respect to a seventh luminance is smaller than the duty ratio of the drive current with respect to an eighth luminance that is higher than the seventh luminance. ### Claim 23 (depends on 20) The display device according to claim 20, wherein the duty ratio of the drive current at the predetermined luminance is configured based on a response speed of the display.