# US 11,308,892 B2 · Organic light emitting display device and driving method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,308,892 B2 - Document ID: US11308892B2 - Status: Granted - Kind: B2 - Application number: 17/102,124 - Filed: 2020-11-23 - Published: 2021-06-03 - Granted: 2022-04-19 - Earliest claimed: 2019-12-03 - Assignees: LG Display Co., Ltd. - Applicants: LG Display Co., Ltd. - Inventors: Kyung-Hyun Cho; Jae-Deok Ko; Seong-Eok Han - Web page: https://patentgrep.com/patent/US11308892B2 ## 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 3/3291: in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements - G09G 3/3258: with pixel circuitry controlling the voltage across the light-emitting element - G09G 3/3266: Details of drivers for scan electrodes - G09G 3/3208: organic, e.g. using organic light-emitting diodes [OLED] - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 2310/0291: Details of output amplifiers or buffers arranged for use in a driving circuit - G09G 2310/08: Details of timing specific for flat panels, other than clock recovery - G09G 2320/0285: using tables for spatial correction of display data - G09G 2320/0295: by monitoring each display pixel - G09G 2320/0693: Calibration of display systems - 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 The disclosure relates to an organic light emitting display device that can detect a defect in a scan transistor in the device in which the scan transistor and a sensing transistor simultaneously operate, and the device includes: an OLED in a subpixel; a driving transistor connected between the OLED and a driving voltage line; a scan transistor connected between a first node through which a data voltage is applied to the driving transistor and a data line; a sensing transistor connected between a second node between the driving transistor, the OLED, and a reference voltage line; and a defect detector for applying the data voltage in a state in which both the scan transistor and the sensing transistor are turned off and then detecting an amount of charges charged in a parasitic capacitor of the OLED to determine whether the scan transistor is defective due to foreign substances. ## Claims ### Claim 1 An organic light emitting display device, comprising: an organic light emitting diode (OLED) disposed in a subpixel; a driving transistor electrically connected between the OLED and a driving voltage line; a scan transistor electrically connected between a first node and a data line, wherein the first node applies a data voltage to the driving transistor; a sensing transistor electrically connected between a second node and a reference voltage line, wherein the second node is disposed between the driving transistor and the OLED; and a defect detector for: initiating by providing black data for turning off the driving transistor through a data line in a state in which both the scan transistor and the sensing transistor are turned on and then, applying the data voltage that is greater than the black data through a data line in a state in which both the scan transistor and the sensing transistor are turned off and then, applying the black data through a data line and detecting an amount of current at the second node in a time period in which the sensing transistor is turned on when the black data is applied to the data line to determine whether the scan transistor is defective. ### Claim 2 (depends on 1) The organic light emitting display device of claim 1, wherein the scan transistor and the sensing transistor are simultaneously turned on or simultaneously turned off. ### Claim 3 (depends on 1) The organic light emitting display device of claim 1, wherein the amount of current at the second node is proportional to an amount of current supplied from the driving transistor being turned on by a leakage current applied to a gate electrode of the driving transistor even when the scan transistor is turned off when the data voltage is applied. ### Claim 4 (depends on 1) The organic light emitting display device of claim 1, further comprising a memory for storing coordinates of a subpixel in which the scan transistor is defective. ### Claim 5 (depends on 4) The organic light emitting display device of claim 4, further comprising timing controller for processing a defective subpixel into a dark point using information stored in the memory. ### Claim 6 (depends on 1) The organic light emitting display device of claim 1, wherein the defect detector comprises: a current comparator for comparing the amount of current at the second node to a reference value; and an analog-to-digital converter for converting output result of the current comparator into a digital signal. ### Claim 7 (depends on 6) The organic light emitting display device of claim 6, wherein the current comparator comprises: an operational amplifier receiving a voltage value corresponding to the amount of current at the second node through an inverting input terminal and receiving a reference voltage through a non-inverting input terminal; and a feedback capacitor connected between the inverting input terminal and an output terminal of the operational amplifier. ### Claim 8 (depends on 7) The organic light emitting display device of claim 7, wherein the current comparator further comprises a current conveyor connected to the inverting input terminal of the operational amplifier and wherein the current conveyor converts current corresponding to the amount of current at the second node. ### Claim 9 A driving method of an organic light emitting display device, comprising: initiating by providing black data for turning off a driving transistor through a data line in a state in which both a scan transistor and a sensing transistor are turned on; supplying a data voltage that is greater than the black data through a data line in a state in which both the scan transistor and the sensing transistor are turned off; and applying the black data through a data line and detecting an amount of current at a node in a time period in which the sensing transistor is turned on when the black data is applied to the data line; and determining whether the scan transistor is defective corresponding to the amount of current at the node. ### Claim 10 (depends on 9) The driving method of claim 9, wherein the amount of current at the node is proportional to an amount of current supplied from the driving transistor being turned on even when the scan transistor is turned off when the data voltage is applied. ### Claim 11 (depends on 9) The driving method of claim 9, wherein the detecting of the amount of current at the node comprises comparing an amount of current at the node with a reference value using a current comparator. ### Claim 12 (depends on 9) The driving method of claim 9, further comprising: storing coordinates of a subpixel in which the scan transistor is defective in a memory; and processing a defective subpixel corresponding to coordinates stored in the memory into a dark point.