# US 10,311,786 B2 · Light emitting display device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,311,786 B2 - Document ID: US10311786B2 - Status: Granted - Kind: B2 - Application number: 15/707,083 - Filed: 2017-09-18 - Published: 2018-03-29 - Granted: 2019-06-04 - Earliest claimed: 2016-09-26 - Assignees: Samsung Display Co., Ltd. - Applicants: Samsung Display Co., Ltd. - Inventors: Wonsik Oh; Myungho Lee; Geunjeong Park; Myoungseop Song - Web page: https://patentgrep.com/patent/US10311786B2 ## CPC - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 3/3225: using an active matrix - G09G 3/3258: with pixel circuitry controlling the voltage across the light-emitting element - G09G 3/3266: Details of drivers for scan electrodes - G09G 2300/0866: by means of changes in the pixel supply voltage - 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 2330/021: Power management, e.g. power saving - G09G 2330/028: Generation of voltages supplied to electrode drivers in a matrix display other than LCD - 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 light emitting display device including: a display panel; a plurality of pixels included in the display panel, each of the plurality of pixels including a driving switching element connected to a first power line and a light emitting element connected to a second power line; a maximum voltage detection unit for detecting a voltage from each of the light emitting elements of each of the pixels and outputting a maximum voltage that has a highest voltage level among the detected voltages; and a power supply unit for correcting a first driving voltage based on the maximum voltage and applying the corrected first driving voltage to the first power line. ## Claims ### Claim 1 A light emitting display device, comprising: a display panel including a plurality of pixels, each of the plurality of pixels comprising a driving switching element connected to a first power line and a light emitting element connected to a second power line; a maximum voltage detection unit for detecting a voltage from each of the light emitting elements of each of the pixels and outputting a maximum voltage that has a highest voltage level among the detected voltages; and a power supply unit for correcting a first driving voltage based on the maximum voltage and applying the corrected first driving voltage to the first power line, wherein the maximum voltage detection unit comprises a plurality of diode-type elements, a first terminal and a second terminal of each of the plurality of diode-type elements are connected to each other and a corresponding one of the light emitting elements, and a third terminal of each of the plurality of diode-type elements is connected in common to a feedback input terminal of the power supply unit, the maximum voltage being applied to the feedback input terminal, and the feedback input terminal is connected to the second power-line. ### Claim 2 (depends on 1) The light emitting display device as claimed in claim 1, wherein the maximum voltage detection unit further comprises a resistor connected between the feedback input terminal and the second power line. ### Claim 3 (depends on 1) The light emitting display device as claimed in claim 1, wherein at least one of the diode-type elements is a diode-type transistor. ### Claim 4 (depends on 1) The light emitting display device as claimed in claim 1, wherein the power supply unit decreases the first driving voltage as the maximum voltage decreases. ### Claim 5 (depends on 1) The light emitting display device as claimed in claim 1, wherein the power supply unit corrects the first driving voltage so that a difference voltage between the first driving voltage and a second driving voltage of the second power line is substantially equal to a sum of the maximum voltage and a minimum drain-source voltage of a driving switching element. ### Claim 6 A light emitting display device, comprising: a plurality of first pixels in a first display area of a display panel, each of the plurality of first pixels comprising a first driving switching element connected to a first power line and a first light emitting element connected to a second power line; a first maximum voltage detection unit for detecting a voltage from each of the first light emitting elements of each of the first pixels and outputting a first maximum voltage that has a highest voltage level among the detected voltages; a first power supply unit for correcting a first driving voltage based on the first maximum voltage and applying the corrected first driving voltage to the first power line; a plurality of second pixels in a second display area of the display panel, each of the plurality of second pixels comprising a second driving switching element connected to a third power line and a second light emitting element connected to the second power line; a second maximum voltage detection unit for detecting a voltage from each of the second light emitting elements of each of the second pixels and outputting a second maximum voltage that has a highest voltage level among the detected voltages; and a second power supply unit for correcting a third driving voltage based on the second maximum voltage and applying the corrected third driving voltage to the third power line, wherein the first maximum voltage detection unit comprises: a first resistor connected between a first feedback input terminal of the first power supply unit and the second power line, the first maximum voltage being input to the first feedback input terminal; and a first diode-type element connected between each one of the first light emitting elements of the first pixels and the first resistor, and a first terminal of each of the first diode-type elements is individually connected to a corresponding one of the first light emitting elements of the first pixels, and a second terminal of each of the first diode-type elements is connected in common to the first feedback input terminal. ### Claim 7 (depends on 6) The light emitting display device as claimed in claim 6, wherein the second maximum voltage detection unit comprises: a second resistor connected between a second feedback input terminal of the second power supply unit and the second power line, the second maximum voltage being input to the second feedback input terminal; and a second diode-type element connected between each one of the second light emitting elements of the second pixels and the second resistor, and a first terminal of each of the second diode-type elements is individually connected to a corresponding one of the second light emitting elements of the second pixels, and a second terminal of each of the second diode-type elements is connected in common to the second feedback input terminal. ### Claim 8 (depends on 6) The light emitting display device as claimed in claim 6, wherein the first power supply unit corrects the first driving voltage so that a difference voltage between the first driving voltage and a second driving voltage of the second power line is substantially equal to a sum of the first maximum voltage and a minimum drain-source voltage of a first driving switching element, and the second power supply unit corrects the third driving voltage so that a difference voltage between the second driving voltage and the third driving voltage is substantially equal to a sum of the second maximum voltage and a minimum drain-source voltage of a second driving switching element. ### Claim 9 (depends on 6) The light emitting display device as claimed in claim 6, wherein the first light emitting elements comprise at least two of a red light emitting element, a green light emitting element, a blue light emitting element, and a white light emitting element. ### Claim 10 (depends on 6) The light emitting display device as claimed in claim 6, wherein the second light emitting elements comprise at least two of a red light emitting element, a green light emitting element, a blue light emitting element, and a white light emitting element. ### Claim 11 A light emitting display device, comprising: a display panel; a plurality of first pixels disposed in the display panel, each of the plurality of first pixels comprising a first driving switching element connected to a first power line and a first light emitting element connected to a second power line; a first maximum voltage detection unit for detecting a voltage from each of the first light emitting elements of each of the first pixels and outputting a first maximum voltage that has a highest voltage level among the detected voltages; a first power supply unit for correcting a first driving voltage based on the first maximum voltage and applying the corrected first driving voltage to the first power line; a plurality of second pixels disposed in the display panel, each of the plurality of second pixels comprising a second driving switching element connected to a third power line and a second light emitting element connected to the second power line; a second maximum voltage detection unit for detecting a voltage from each of the second light emitting elements of each of the second pixels and outputting a second maximum voltage that has a highest voltage level among the detected voltages; and a second power supply unit for correcting a third driving voltage based on the second maximum voltage and applying the corrected third driving voltage to the third power line, wherein the first light emitting element emits a light having a color different from a color of a light emitted from the second light emitting element, wherein the first maximum voltage detection unit comprises: a first resistor connected between a first feedback input terminal of the first power supply unit and the second power line, the first maximum voltage being input to the first feedback input terminal; and a first diode-type element connected between each one of the first light emitting elements of the first pixels and the first resistor, and a first terminal of each of the first diode-type elements is individually connected to a corresponding one of the first light emitting elements of the first pixels, and a second terminal of each of the first diode-type elements is connected in common to the first feedback input terminal. ### Claim 12 (depends on 11) The light emitting display device as claimed in claim 11, wherein the second maximum voltage detection unit comprises: a second resistor connected between a second feedback input terminal of the second power supply unit and the second power line, the second maximum voltage being input to the second feedback input terminal; and a second diode-type element connected between each one of the second light emitting elements of the second pixels and the second resistor, and a first terminal of each of the second diode-type elements is individually connected to a corresponding one of the second light emitting elements of the second pixels, and a second terminal of each of the second diode-type elements is connected in common to the second feedback input terminal. ### Claim 13 (depends on 11) The light emitting display device as claimed in claim 11, wherein the first power supply unit corrects the first driving voltage so that a difference voltage between the first driving voltage and a second driving voltage of the second power line is substantially equal to a sun of the first maximum voltage and a minimum drain-source voltage of a first driving switching element, and the second power supply unit corrects the third driving voltage so that a difference voltage between the second driving voltage and the third driving voltage is substantially equal to a sum of the second maximum voltage and a minimum drain-source voltage of a second driving switching element. ### Claim 14 (depends on 11) The light emitting display device as claimed in claim 11, wherein the first light emitting elements comprise at least one of a red light emitting element, a green light emitting element, a blue light emitting element, and a white light emitting element. ### Claim 15 (depends on 11) The light emitting display device as claimed in claim 11, wherein the second light emitting elements comprise at least one of a red light emitting element, a green light emitting element, a blue light emitting element, and a white light emitting element. ### Claim 16 A light emitting display device, comprising: a display panel including a plurality of pixels, each of the plurality of pixels comprising a driving switching element connected to a first power line and a light emitting element connected to a second power line; a maximum voltage detection unit for detecting a voltage from each of the light emitting elements of each of the pixels and outputting a maximum voltage that has a highest voltage level among the detected voltages; a timing controller for outputting a highest gray level image data signal having a highest gray level among image data signals applied to the plurality of pixels; a compensation voltage selection unit for storing compensation voltages corresponding to respective gray levels of a plurality of image data signals and selecting a compensation voltage corresponding to the highest gray level image data signal; a compensation voltage update unit for correcting the compensation voltage of the compensation voltage selection unit corresponding to the highest gray level image data signal based on the maximum voltage; and a power supply unit for correcting a first driving voltage based on the compensation voltage selected by the compensation voltage selection unit and applying the corrected first driving voltage to the first power line, wherein, when the number of image data signals having a lower gray level than a reference gray level among the image data signals applied to the plurality of pixels exceeds a threshold value, the timing controller further generates a holding signal and applies the holding signal to the compensation voltage update unit. ### Claim 17 (depends on 16) The light emitting display device as claimed in claim 16, wherein the compensation voltage update unit further corrects at least one other compensation voltage stored in the compensation voltage selection unit based on a variation amount of the compensation voltage corrected according to the maximum voltage. ### Claim 18 (depends on 16) The light emitting display device as claimed in claim 16, wherein, in response to the holding signal, the compensation voltage update unit maintains the compensation voltages of the compensation voltage selection unit to keep values they had before the generation of the highest gray level image data signal, regardless of an input of the highest gray level image data signal. ### Claim 19 (depends on 16) The light emitting display device as claimed in claim 16, wherein the compensation voltage update unit corrects the compensation voltage once every y-th horizontal period, wherein y is a natural number greater than 2. ### Claim 20 (depends on 16) The light emitting display device as claimed in claim 16, wherein the maximum voltage detection unit comprises: a resistor connected between a feedback input terminal of the compensation voltage update unit and the second power line, the maximum voltage being input to the feedback input terminal; and a diode-type element connected between each one of the light emitting elements and the resistor, and a first terminal of each of the diode-type elements is individually connected to a corresponding one of the light emitting elements, and a second terminal of each of the diode-type elements is connected in common to the feedback input terminal. ### Claim 21 (depends on 16) The light emitting display device as claimed in claim 16, wherein the power supply unit corrects the first driving voltage so that a difference voltage between the first driving voltage and a second driving voltage of the second power line is substantially equal to a sum of the selected compensation voltage and a minimum drain-source voltage of a driving switching element. ### Claim 22 (depends on 16) The light emitting display device as claimed in claim 16, wherein the compensation voltage selection unit is a look-up table. ### Claim 23 A light emitting display device, comprising: a display panel comprising a plurality of pixels, each of the plurality of pixels comprising a driving switching element connected to a first power line and a light emitting element connected to a second power line; a power supply unit for applying a power to the first power line; and a diode directly connected to an anode electrode of the light emitting element disposed in at least one pixel, a driving transistor of the at least one pixel, and a feedback input terminal of the power supply unit, wherein a resistor is connected between the diode and the second power line.