# US 12,190,834 B2 · Display device and local method of controlling local dimming thereof preliminary class > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,190,834 B2 - Document ID: US12190834B2 - Status: Granted - Kind: B2 - Application number: 18/150,318 - Filed: 2023-01-05 - Published: 2023-05-18 - Granted: 2025-01-07 - Earliest claimed: 2020-10-30 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Hyunku Kang - Web page: https://patentgrep.com/patent/US12190834B2 ## CPC - G09G 3/2003: {Display of colours (specific for liquid crystal displays G09G3/3607)} - G09G 3/3426: {the different display panel areas being distributed in two dimensions, e.g. matrix} - G09G 3/2014: {by modulation of the duration of a single pulse during which the logic level remains constant} - G09G 3/2081: {with combination of amplitude modulation and time modulation (space and time error diffusion G09G3/2066)} - G09G 3/32: semiconductive, e.g. using light-emitting diodes [LED] - G09G 3/3406: {Control of illumination source (illumination devices structurally associated with liquid crystal cells G02F1/1336)} - G09G 2300/023: Display panel composed of stacked panels - G09G 2310/08: Details of timing specific for flat panels, other than clock recovery - G09G 2320/0653: Controlling or limiting the speed of brightness adjustment of the illumination source - G09G 2320/08: Arrangements within a display terminal for setting, manually or automatically, display parameters of the display terminal - 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 - 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 display device may include a display panel, a backlight unit including a plurality of blocks for providing light to the display panel, each of the plurality of blocks comprising a plurality of light emitting diodes (LEDs), and a controller configured to obtain backlight control information and to activate a duty ratio control function for controlling a duty ratio and current flowing in a block during a cycle of one frame, when a low current condition is satisfied based on the obtained backlight control information. ## Claims ### Claim 1 A display device comprising: a display panel; a backlight unit including a plurality of blocks for providing light to the display panel, each of the plurality of blocks comprising a plurality of light emitting diodes (LEDs); and a controller configured to: obtain backlight control information, obtain a Pulse Width Modulation (PWM) dimming duty ratio value from the backlight control information, determine that a backlight control value included in the backlight control information is less than a predetermined value, increase a voltage applied to a block and reduce a duty ratio during a cycle of one frame, based on the backlight control value being less than the predetermined value, wherein the backlight control value comprises the PWM dimming duty ratio value, and wherein the controller is further configured to determine that the backlight control value is less than the predetermined value, based on the PWM dimming duty ratio value being less than a predetermined dimming value, wherein the controller is further configured to control the block such that current flowing in the block during a half cycle of one frame is different from current flowing in the block during the other half cycle. ### Claim 2 (depends on 1) The display device of claim 1, wherein the controller is further configured to reduce the duty ratio and increase the voltage such that a product (a*b) of an increase multiple a of current flowing in the block and the duty ratio b becomes 1. ### Claim 3 (depends on 2) The display device of claim 2, wherein the controller is further configured to reduce the duty ratio and increase the voltage such that the duty ratio b becomes ((1/n)×100) % when the increase multiple a is n times. ### Claim 4 (depends on 1) The display device of claim 1, wherein the backlight control value further comprises a voltage value applied to the block, and wherein the controller is further configured to determine a value of current flowing in the block based on the voltage value, and determine that the backlight control value is less than the predetermined value, based on the determined current value being less than a predetermined current value. ### Claim 5 (depends on 1) The display device of claim 1, wherein the current flowing in the block during the half cycle of the one frame is smaller than the current flowing in the block during the other half cycle. ### Claim 6 (depends on 1) The display device of claim 1, wherein the current flowing in the block is 0 during the half cycle of the one frame. ### Claim 7 A local dimming control method of a display device comprising a display panel and a backlight unit including a plurality of blocks for providing light to the display panel, the local dimming control method comprising: obtaining backlight control information; obtaining a Pulse Width Modulation (PWM) dimming duty ratio value from the backlight control information; determining that a backlight control value included in the backlight control information is less than a predetermined value; and increasing a voltage applied to a block and reducing a duty ratio during a cycle of one frame, based on the backlight control value being less than the predetermined value, wherein the backlight control value comprises the PWM dimming duty ratio value, and wherein determining that the backlight control value is less than the predetermined value comprises determining that the backlight control value is less than the predetermined value, based on the PWM dimming duty ratio value being less than a predetermined dimming value, wherein increasing the voltage and reducing the duty ratio further comprise controlling the block such that current flowing in the block during a half cycle of one frame is different from current flowing in the block during the other half cycle. ### Claim 8 (depends on 7) The local dimming control method of claim 7, wherein increasing the voltage and reducing the duty ratio comprise increasing the voltage and reducing the duty ratio such that a product (a*b) of an increase multiple a of current flowing in the block and the duty ratio b becomes 1. ### Claim 9 (depends on 8) The local dimming control method of claim 8, wherein increasing the voltage and reducing the duty ratio further comprise increasing the voltage and reducing the duty ratio such that the duty ratio b becomes ((1/n)×100) % when the increase multiple a is n times. ### Claim 10 (depends on 7) The local dimming control method of claim 7, wherein the backlight control value further comprises a voltage value applied to the block, and wherein the local dimming control method further comprises determining a value of current flowing in the block based on the voltage value, and determining that the backlight control value is less than the predetermined value, based on the determined current value being less than a predetermined current value. ### Claim 11 (depends on 7) The local dimming control method of claim 7, wherein the current flowing in the block during the half cycle of the one frame is smaller than the current flowing in the block during the other half cycle. ### Claim 12 (depends on 7) The local dimming control method of claim 7, wherein the current flowing in the block is 0 during the half cycle of the one frame. ### Claim 13 (depends on 12) The local dimming control method of claim 12, wherein the current flowing in the block is n times a current value of a previous frame during the other half cycle. ### Claim 14 (depends on 13) The local dimming control method of claim 13, wherein controlling the block comprises: controlling current flowing in the block such that the current decreases to 0 gradually during a first half-cycle start section of one frame, and controlling current flowing in the block such that the current increases to n times gradually during the other half-cycle start section of one frame. ### Claim 15 (depends on 6) The display device of claim 6, wherein the current flowing in the block is n times a current value of a previous frame during the other half cycle. ### Claim 16 (depends on 15) The display device of claim 15, wherein the controller is further configured to control current flowing in the block such that the current decreases to 0 gradually during a first half-cycle start section of one frame, and control current flowing in the block such that the current increases to n times gradually during the other half-cycle start section of one frame.