# US 2023/0057700 A1 · Display device and display driving method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0057700 A1 - Document ID: US20230057700A1 - Status: Published application - Kind: A1 - Application number: 17/842,023 - Filed: 2022-06-16 - Published: 2023-02-23 - Earliest claimed: 2021-08-18 - Assignees: LG Display Co., Ltd. - Applicants: LG Display Co., Ltd. - Inventors: Jinwon KIM; MooKyoung HONG - Web page: https://patentgrep.com/patent/US20230057700A1 ## CPC - G09G 3/006: {Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays (testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309)} - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 3/2074: {using sub-pixels} - 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 2300/0866: by means of changes in the pixel supply voltage - G09G 2320/0295: by monitoring each display pixel - G09G 2330/028: Generation of voltages supplied to electrode drivers in a matrix display other than LCD - G09G 2330/04: Display protection - G09G 2330/08: Fault-tolerant or redundant circuits, or circuits in which repair of defects is prepared - G09G 2330/10: Dealing with defective pixels - G09G 2330/12: Test circuits or failure detection circuits included in a display system, as permanent part thereof - 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 includes a display panel in which a plurality of subpixels including a light emitting element that emits light by a high potential voltage supplied to a driving voltage line, and a plurality of reference voltage lines connected to the plurality of subpixels to detect a characteristic value are disposed; a data driving circuit configured to supply a low potential voltage to the driving voltage line through the plurality of reference voltage lines; a base voltage switching circuit configured to control a ground voltage node connected to a cathode electrode of the light emitting element; a current detecting circuit configured to detect a current flowing between the base voltage node and a ground; and a timing controller configured to control the base voltage switching circuit and generate a defect detection signal for the driving voltage line according to a current detected by the current detecting circuit. ## Claims ### Claim 1 A display device comprising: a display panel in which a plurality of subpixels including a light emitting element that emits light by a high potential voltage supplied to a driving voltage line, and a plurality of reference voltage lines connected to the plurality of subpixels to detect a characteristic value are disposed; a data driving circuit configured to supply a low potential voltage, lower than the high potential voltage, to the driving voltage line through the plurality of reference voltage lines; a base voltage switching circuit configured to control a base voltage node connected to a cathode electrode of the light emitting element; a current detecting circuit configured to detect a current flowing between the base voltage node and a ground; and a timing controller configured to control the base voltage switching circuit and generate a defect detection signal for the driving voltage line according to a current detected by the current detecting circuit. ### Claim 2 (depends on 1) The display device according to claim 1, wherein the data driving circuit is configured to supply the low potential voltage in a period in which the high potential voltage is not supplied to the driving voltage line. ### Claim 3 (depends on 1) The display device according to claim 1, wherein the data driving circuit is configured to supply the low potential voltage to the driving voltage line in a period in which the base voltage node is floated. ### Claim 4 (depends on 1) The display device according to claim 1, wherein the low potential voltage is a display driving reference voltage supplied in a display driving period. ### Claim 5 (depends on 1) The display device according to claim 1, wherein a subpixel of the plurality of subpixels includes: a driving transistor of which third node receives the high potential voltage and which provides a current to the light emitting element through the driving voltage line; a switching transistor electrically connected between a first node of the driving transistor and a data line; a sensing transistor electrically connected between a second node of the driving transistor and a corresponding reference voltage line of the plurality of reference voltage lines; and a storage capacitor electrically connected between the first node and the second node of the driving transistor; wherein the light emitting element is electrically connected between the second node of the driving transistor and the base voltage node. ### Claim 6 (depends on 5) The display device according to claim 5, wherein the subpixel is configured such that a first current path flowing to the third node of the driving transistor through the sensing transistor and the driving transistor is formed by the low potential voltage. ### Claim 7 (depends on 1) The display device according to claim 1, wherein the subpixel is configured such that a second current path flowing from the base voltage node to the ground is formed when the driving voltage line is defective. ### Claim 8 (depends on 1) The display device according to claim 1, wherein the current detecting circuit includes: a resistor electrically connected between the base voltage node and the ground; an operational amplifier having an inverting input terminal and a non-inverting input terminal connected to both ends of the resistor to generate a voltage proportional to a current flowing through the resistor; and a level detecting circuit configured to generate a result of comparing an output value from the operational amplifier and a reference value. ### Claim 9 (depends on 8) The display device according to claim 8, wherein the timing controller is configured to generate a defect detection signal for the driving voltage line according to an output value of the level detecting circuit. ### Claim 10 A display driving method for driving a display device including a display panel in which a plurality of subpixels with a light emitting element that emits light by a high potential voltage supplied to a driving voltage line and a plurality of reference voltage lines connected to the plurality of subpixels to detect a characteristic value are disposed, comprising: maintaining a high potential voltage node at a level lower than a display driving reference voltage; floating a base voltage node; supplying a low potential voltage, lower than the high potential voltage, to a driving voltage line; detecting a current between the base voltage node and a ground; comparing a detected current with a reference value; and generating a defect detection signal according to a result of comparing the detected current with the reference value. ### Claim 11 (depends on 10) The display driving method according to claim 10, wherein the low potential voltage is supplied through the plurality of reference voltage lines. ### Claim 12 (depends on 10) The display driving method according to claim 10, wherein the low potential voltage is supplied in a period to which the high potential voltage is not supplied. ### Claim 13 (depends on 10) The display driving method according to claim 10, wherein the low potential voltage is a display driving reference voltage supplied in a display driving period. ### Claim 14 (depends on 10) The display driving method according to claim 10, wherein a subpixel of the plurality of subpixels includes: a driving transistor of which third node receives the high potential voltage and which provides a current to the light emitting element through the driving voltage line; a switching transistor electrically connected between a first node of the driving transistor and a data line; a sensing transistor electrically connected between a second node of the driving transistor and a corresponding reference voltage line of the plurality of reference voltage lines; and a storage capacitor electrically connected between the first node and the second node of the driving transistor; and wherein the light emitting element is electrically connected between the second node of the driving transistor and the base voltage node. ### Claim 15 (depends on 10) The display driving method according to claim 10, wherein a first current path flowing to the third node of the driving transistor through the sensing transistor and the driving transistor is formed by the low potential voltage. ### Claim 16 (depends on 10) The display driving method according to claim 10, wherein a second current path flowing from the base voltage node to the ground is formed when the driving voltage line is defective. ### Claim 17 (depends on 10) The display driving method according to claim 10, wherein the generating a defect detection signal includes: generating a defect detection signal with a high level when the detected current is equal to or greater than the reference value; and generating a defect detection signal with a low level lower than the high level when the detected current is less than the reference value.