# US 12,603,053 B2 · Pixel circuits and display device using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,603,053 B2 - Document ID: US12603053B2 - Status: Granted - Kind: B2 - Application number: 18/990,316 - Filed: 2024-12-20 - Published: 2025-07-03 - Granted: 2026-04-14 - Earliest claimed: 2023-12-29 - Assignees: LG Display Co., Ltd. - Applicants: LG Display Co., Ltd. - Inventors: Ki Tae Kwon; Yong Won Jo; Jong Wook Jang - Web page: https://patentgrep.com/patent/US12603053B2 ## CPC - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 3/2007: {Display of intermediate tones} - G09G 2300/0819: used for counteracting undesired variations, e.g. feedback or autozeroing - G09G 2300/0842: forming a memory circuit, e.g. a dynamic memory with one capacitor - G09G 2310/027: Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters - G09G 2310/0297: Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns - G09G 2310/08: Details of timing specific for flat panels, other than clock recovery - G09G 2320/045: Compensation of drifts in the characteristics of light emitting or modulating elements - G09G 2330/021: Power management, e.g. power saving - 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 pixel circuit can include an internal compensation unit having a driving transistor and a capacitor having a first terminal connected to a gate electrode of the driving transistor. Data lines are connected to a first electrode of the driving transistor and a second terminal of the capacitor, respectively, so that a light-emitting element emits light with a grayscale corresponding to a difference between data voltages charged in the capacitor. Accordingly, the number of bits of data output from channels of a data driving circuit can be reduced. ## Claims ### Claim 1 A pixel circuit comprising: a light-emitting element; a driving transistor electrically connected to the light-emitting element through a second electrode thereof to supply a current to the light-emitting element, and controlled by a voltage applied to a gate electrode thereof; a capacitor having a first terminal connected to the gate electrode of the driving transistor; and an internal compensation unit including a plurality of switch elements to sense a threshold voltage of the driving transistor during a sampling period, and supply a current, in which the threshold voltage is compensated for, to the light-emitting element, wherein data lines, through which an analog data voltage converted from a digital data signal is supplied, are connected to the internal compensation unit, the digital data signal being configured to adjust a light emission grayscale of the light-emitting element based on a number of bits thereof, wherein the data lines include a first data line and a second data line, the first data line being electrically connected to a first electrode of the driving transistor, and the second data line being electrically connected to a second terminal of the capacitor, and wherein the light-emitting element emits light with a grayscale corresponding to a first voltage by charging a difference between a voltage of the second data line and a voltage of the first data line as the first voltage in the capacitor during the sampling period, wherein the voltage of the first data line is a data voltage for lower bits of the digital data signal, wherein the voltage of the second data line is a data voltage for upper bits of the digital data signal, wherein the number of bits of the digital data signal is an even natural number, and wherein each of a number of the upper bits and a number of the lower bits is half of the number of bits of the digital data signal. ### Claim 2 (depends on 1) The pixel circuit of claim 1, wherein the first voltage charged in the capacitor is applied to the voltage of the gate electrode of the driving transistor during a programming period. ### Claim 3 (depends on 2) The pixel circuit of claim 2, wherein the voltage of the gate electrode, to which the first voltage is applied, of the driving transistor is constantly maintained through the capacitor during a light emission period to generate a constant current for driving the light-emitting element. ### Claim 4 A pixel circuit comprising: a light-emitting element; a driving transistor electrically connected to the light-emitting element through a second electrode thereof to supply a current to the light-emitting element, and controlled by a voltage applied to a gate electrode thereof; a capacitor having a first terminal connected to the gate electrode of the driving transistor; and an internal compensation unit including a plurality of switch elements to sense a threshold voltage of the driving transistor during a sampling period, and supply a current, in which the threshold voltage is compensated for, to the light-emitting element, wherein data lines, through which an analog data voltage converted from a digital data signal is supplied, are connected to the internal compensation unit, the digital data signal being configured to adjust a light emission grayscale of the light-emitting element based on a number of bits thereof, wherein the data lines include a first data line and a second data line, the first data line being electrically connected to a first electrode of the driving transistor, and the second data line being electrically connected to a second terminal of the capacitor, wherein the light-emitting element emits light with a grayscale corresponding to a first voltage by charging a difference between a voltage of the second data line and a voltage of the first data line as the first voltage in the capacitor during the sampling period, wherein the first data line is electrically connected to the first electrode of the driving transistor through a first switch element, wherein the second data line is electrically connected to the second terminal of the capacitor through a second switch element, wherein the first switch element and the second switch element are controlled by a same scan signal and are turned on during the sampling period, and wherein the second terminal of the capacitor is electrically connected to a pixel driving voltage line through one or more switch elements that are turned off during the sampling period. ### Claim 5 (depends on 4) The pixel circuit of claim 4, wherein the plurality of switch elements are thin-film transistors, wherein each of the one or more switch elements that are turned off during the sampling period is an n-channel transistor that is controlled by the same scan signal that controls the first and second switch elements, and wherein the first and second switch elements are p-channel transistors. ### Claim 6 (depends on 4) The pixel circuit of claim 4, wherein the plurality of switch elements are p-channel thin-film transistors, and wherein the one or more switch elements that are turned off during the sampling period include a switch element controlled by a scan signal and a switch element controlled by an emission signal, which are connected in parallel. ### Claim 7 A display device comprising: a display panel in which data lines and gate lines crossing each other are disposed, the display panel including pixels; a data driver configured to convert a digital data signal into an analog data voltage and supply the analog data voltage to the data lines; a gate driver configured to supply a gate signal to the gate lines; a timing controller configured to transmit the digital data signal to the data driver and generate a signal for controlling operation timings of the data driver and the gate driver; and a power supply unit configured to generate voltages for driving the pixels, the data driver, the gate driver, and the timing controller, wherein each of the pixels includes sub-pixels each having a pixel circuit, wherein the pixel circuit includes: a light-emitting element; a driving transistor electrically connected to the light-emitting element through a second electrode thereof to supply a current to the light-emitting element, and controlled by a voltage applied to a gate electrode thereof; a capacitor having a first terminal connected to the gate electrode of the driving transistor; and an internal compensation unit including a plurality of switch elements to sense a threshold voltage of the driving transistor during a sampling period and supply a current, in which the threshold voltage is compensated for, to the light-emitting element, wherein the data lines are connected to the internal compensation unit and adjust a light emission grayscale of the light-emitting element based on a number of bits of the digital data signal, wherein the data lines connected to the internal compensation unit include a first data line and a second data line, the first data line being electrically connected to a first electrode of the driving transistor, and the second data line being electrically connected to a second terminal of the capacitor, wherein the light-emitting element emits light with a grayscale corresponding to a first voltage by charging a difference between a voltage of the second data line and a voltage of the first data line as the first voltage in the capacitor during the sampling period, wherein the voltage of the first data line supplied to the pixel circuit is a data voltage for lower bits of the digital data signal, wherein the voltage of the second data line supplied to the pixel circuit is a data voltage for upper bits of the digital data signal, wherein the number of bits of the digital data signal is an even natural number, and wherein each of a number of the upper bits and a number of the lower bits is half of the number of bits of the digital data signal. ### Claim 8 (depends on 7) The display device of claim 7, wherein the first voltage charged in the capacitor is applied to the voltage of the gate electrode of the driving transistor during a programming period. ### Claim 9 (depends on 8) The display device of claim 8, wherein the voltage of the gate electrode, to which the first voltage is applied, of the driving transistor is constantly maintained through the capacitor during a light emission period to generate a constant current for driving the light-emitting element. ### Claim 10 (depends on 7) The display device of claim 7, further comprising a demultiplexing unit configured to distribute the data voltage converted from the digital data signal by the data driver to the data lines, wherein one of the gate lines and two of the data lines are connected to each of the sub-pixels of the display panel, wherein the two data lines connected to each of the sub-pixels include; a data line to which one of voltages, obtained by dividing the digital data signal into two parts and converting each, is supplied through one channel of the data driver, and a data line, to which the other one of the voltages is supplied by being provided through another channel of the data driver and being distributed by the demultiplexing unit, and wherein the first and second data lines are the two data lines connected to each of the sub-pixels. ### Claim 11 A display device comprising: a display panel in which data lines and gate lines crossing each other are disposed, the display panel including pixels; a data driver configured to convert a digital data signal into an analog data voltage and supply the analog data voltage to the data lines; a gate driver configured to supply a gate signal to the gate lines; a timing controller configured to transmit the digital data signal to the data driver and generate a signal for controlling operation timings of the data driver and the gate driver; and a power supply unit configured to generate voltages for driving the pixels, the data driver, the gate driver, and the timing controller, wherein each of the pixels includes sub-pixels each having a pixel circuit, wherein the pixel circuit includes; a light-emitting element; a driving transistor electrically connected to the light-emitting element through a second electrode thereof to supply a current to the light-emitting element, and controlled by a voltage applied to a gate electrode thereof; a capacitor having a first terminal connected to the gate electrode of the driving transistor; and an internal compensation unit including a plurality of switch elements to sense a threshold voltage of the driving transistor during a sampling period and supply a current, in which the threshold voltage is compensated for, to the light-emitting element, wherein the data lines are connected to the internal compensation unit and adjust a light emission grayscale of the light-emitting element based on a number of bits of the digital data signal, wherein the data lines connected to the internal compensation unit include a first data line and a second data line, the first data line being electrically connected to a first electrode of the driving transistor, and the second data line being electrically connected to a second terminal of the capacitor, wherein the light-emitting element emits light with a grayscale corresponding to a first voltage by charging a difference between a voltage of the second data line and a voltage of the first data line as the first voltage in the capacitor during the sampling period, wherein the first data line is electrically connected to the first electrode of the driving transistor through a first switch element, wherein the second data line is electrically connected to the second terminal of the capacitor through a second switch element, wherein the first switch element and the second switch element are controlled by a same scan signal and are turned on during the sampling period, wherein the power supply unit supplies voltages for driving the pixels to a pixel driving voltage line, and wherein the second terminal of the capacitor is electrically connected to the pixel driving voltage line through one or more switch elements that are turned off during the sampling period. ### Claim 12 (depends on 11) The display device of claim 11, wherein the plurality of switch elements are thin-film transistors, wherein each of the one or more switch elements that are turned off during the sampling period is an n-channel transistor that is controlled by the same scan signal that controls the first and second switch elements, and wherein the first and second switch elements are p-channel transistors. ### Claim 13 (depends on 11) The display device of claim 11, wherein the plurality of switch elements are p-channel thin-film transistors, and wherein the one or more switch elements that are turned off during the sampling period include a switch element controlled by a scan signal and a switch element controlled by an emission signal, which are connected in parallel. ### Claim 14 A display device comprising: a display panel in which a plurality of data lines and a plurality of gate lines crossing each other are disposed, the display panel including pixels; a data driver configured to convert a digital data signal into an analog data voltage and supply the analog data voltage to the data lines; and a demultiplexing unit configured to distribute the data voltage converted from the digital data signal by the data driver to the data lines, wherein each of the pixels includes sub-pixels each having a pixel circuit, wherein one of the gate lines and two of the data lines are connected to each of the sub-pixels, wherein the two data lines connected to each of the sub-pixels include: a first data line to which one of voltages, obtained by dividing the digital data signal into two parts and converting each, is supplied through one channel of the data driver, and a second data line, to which the other one of the voltages is supplied by being provided through another channel of the data driver and being distributed by the demultiplexing unit, wherein the pixel circuit includes: a light-emitting element; a driving transistor electrically connected to the light-emitting element through a second electrode thereof to supply a current to the light-emitting element, and controlled by a voltage applied to a gate electrode thereof; a capacitor having a first terminal connected to the gate electrode of the driving transistor; and an internal compensation unit including a plurality of switch elements to sense a threshold voltage of the driving transistor during a sampling period and supply a current, in which the threshold voltage is compensated for, to the light-emitting element, wherein the first data line and the second data line, which are data lines connected to each of the sub-pixels, are connected to the internal compensation unit and adjust a light emission grayscale of the light-emitting element based on a number of bits of the digital data signal, the first data line being electrically connected to a first electrode of the driving transistor, and the second data line being electrically connected to a second terminal of the capacitor, wherein the light-emitting element emits light with a grayscale corresponding to a first voltage by charging a difference between a voltage of the second data line and a voltage of the first data line as the first voltage in the capacitor during the sampling period, wherein the first data line is electrically connected to the first electrode of the driving transistor through a first switch element, wherein the second data line is electrically connected to the second terminal of the capacitor through a second switch element, wherein the first switch element and the second switch element are controlled by a same scan signal and are turned on during the sampling period, wherein a power supply unit supplies voltages for driving the pixels to a pixel driving voltage line, and wherein the second terminal of the capacitor is electrically connected to the pixel driving voltage line through one or more switch elements that are turned off during the sampling period.