# US 10,373,554 B2 · Pixels and reference circuits and timing techniques > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,373,554 B2 - Document ID: US10373554B2 - Status: Granted - Kind: B2 - Application number: 15/361,660 - Filed: 2016-11-28 - Published: 2017-03-16 - Granted: 2019-08-06 - Earliest claimed: 2015-07-24 - Assignees: Ignis Innovation Inc. - Applicants: Ignis Innovation Inc. - Inventors: Gholamreza Chaji; Yaser Azizi - Web page: https://patentgrep.com/patent/US10373554B2 ## CPC - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 2300/0819: used for counteracting undesired variations, e.g. feedback or autozeroing - G09G 2310/061: for resetting or blanking - G09G 2310/08: Details of timing specific for flat panels, other than clock recovery - G09G 2320/0295: by monitoring each display pixel - G09G 2320/045: Compensation of drifts in the characteristics of light emitting or modulating elements - G09G 2320/0693: Calibration of display systems - 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 What is disclosed are systems and methods of compensation of images produced by active matrix light emitting diode device (AMOLED) and other emissive displays. Anomalies in luminance produced by pixel circuits and bias currents produced by current biasing circuits for driving current biased voltage programmed pixels are corrected through calibration and compensation while re-using existing data or other lines that can be controlled individually to perform said calibration and compensation. ## Claims ### Claim 1 A system for generating currents for pixels of an emissive display system, each pixel having a light-emitting device, the system comprising: a plurality of pixels; a plurality of current generating circuits for providing a current for at least one respective pixel; and a controller coupled to said current generating circuits for controlling said current generating circuits over a plurality of signal lines; wherein each current generating circuit comprises: at least one driving transistor for providing the current for the pixel; and a storage capacitance for being programmed and for setting a magnitude of the current provided by the at least one driving transistor; wherein the controller's controlling each current generating circuit comprises: during a programming cycle charging the storage capacitance to a defined level; and subsequent to the programming cycle, during a calibration cycle, partially discharging the storage capacitance as a function of characteristics of the at least one driving transistor. ### Claim 2 (depends on 1) The system of claim 1, wherein the at least one driving transistor comprises a driving transistor and the controller's controlling each current generating circuit further comprises: during the programming cycle charging the storage capacitance connected to a gate terminal of the driving transistor to include at least a threshold voltage of the driving transistor, such that during an emission cycle, a voltage across the source terminal and the drain terminal during the emission cycle is a function of the threshold voltage of the driving transistor. ### Claim 3 (depends on 1) The system of claim 1, wherein the at least one driving transistor comprises a driving transistor and the controller's controlling each current generating circuit further comprises: during the programming cycle charging the storage capacitance connected to a gate terminal of the driving transistor to include at least a first voltage applied to a source terminal of the driving transistor, such that during an emission cycle, during which a first voltage is maintained at the source terminal of the driving transistor, a voltage across the source terminal and the drain terminal is independent of the first voltage. ### Claim 4 (depends on 3) The system of claim 3, wherein the first voltage is one of VDD and VMON. ### Claim 5 (depends on 1) The system of claim 1, wherein each current generating circuit comprises one of a reference current sink and a reference current source for providing the current for the at least one respective pixels, the current provided to provide reference current biasing for the at least one respective pixels. ### Claim 6 (depends on 1) The system of claim 1, wherein each pixel comprises the current generating circuit for providing the current for said pixel, the current provided to drive the light-emitting device of said pixel. ### Claim 7 (depends on 6) The system of claim 6, wherein the light emitting device is an Organic Light Emitting Diode (OLED). ### Claim 8 (depends on 7) The system of claim 7, wherein the controller's controlling each current generating circuit further comprises: during a reset cycle commencing substantially simultaneously with an emission cycle, resetting to a low reference voltage at least one of an anode of the OLED and a terminal of the at least one driving transistor. ### Claim 9 A method for generating currents for pixels of an emissive display system, each pixel having a light-emitting device, the system comprising a plurality of pixels, a plurality of current generating circuits for providing a current for at least one respective pixel, each current generating circuit comprising at least one driving transistor for providing the current for the pixel, and a storage capacitance for being programmed and for setting a magnitude of the current provided by the at least one driving transistor, the method comprising: controlling each current generating circuit over a plurality of lines comprising: charging the storage capacitance to a defined level during a programming cycle; and subsequent to the programming cycle, during a calibration cycle, partially discharging the storage capacitance as a function of characteristics of the at least one driving transistor. ### Claim 10 (depends on 9) The method of claim 9 wherein the at least one driving transistor comprises a driving transistor and controlling each current generating circuit further comprises: during the programming cycle, charging the storage capacitance connected to a gate terminal of the driving transistor to include at least a threshold voltage of the driving transistor, such that during an emission cycle a voltage across the source terminal and the drain terminal is a function of the threshold voltage of the driving transistor. ### Claim 11 (depends on 9) The method of claim 9 wherein the at least one driving transistor comprises a driving transistor and controlling each current generating circuit further comprises: during the programming cycle charging the storage capacitance connected to a gate terminal of the driving transistor to include at least a first voltage applied to a source terminal of the driving transistor, such that during an emission cycle, during which a first voltage is maintained at the source terminal of the driving transistor, a voltage across the source terminal and the drain terminal is independent of the first voltage. ### Claim 12 (depends on 11) The method of claim 11, wherein the first voltage is one of VDD and VMON. ### Claim 13 (depends on 9) The method of claim 9, wherein each current generating circuit comprises one of a reference current sink and a reference current source for providing the current for the at least one respective pixels, the current provided to provide reference current biasing for the at least one respective pixels. ### Claim 14 (depends on 9) The method of claim 9, wherein each pixel comprises the current generating circuit for providing the current for said pixel, the current provided to drive the light-emitting device of said pixel. ### Claim 15 (depends on 14) The method of claim 14, wherein the light emitting device is an Organic Light Emitting Diode (OLED). ### Claim 16 (depends on 15) The method of claim 15, wherein the controlling each current generating circuit further comprises: during a reset cycle commencing substantially simultaneously with an emission cycle, resetting to a low reference voltage at least one of an anode of the OLED and a terminal of the at least one driving transistor.