# US 2015/0145902 A1 · Display device and method for driving display device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2015/0145902 A1 - Document ID: US20150145902A1 - Status: Published application - Kind: A1 - Application number: 14/554,614 - Filed: 2014-11-26 - Published: 2015-05-28 - Earliest claimed: 2013-11-27 - Assignees: Japan Display Inc. - Applicants: Japan Display Inc. - Inventors: Hiroshi NAKAYAMA; Tetsuo MORITA; Hiroyuki KIMURA; Makoto SHIBUSAWA - Web page: https://patentgrep.com/patent/US20150145902A1 ## CPC - G09G 3/3266: Details of drivers for scan electrodes - 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 2300/0842: forming a memory circuit, e.g. a dynamic memory with one capacitor - G09G 2300/0861: with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes - G09G 2310/066: Waveforms comprising a gently increasing or decreasing portion, e.g. ramp - G09G 2320/0233: Improving the luminance or brightness uniformity across the screen - 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 According to one embodiment, a display device includes a plurality of pixel units which each includes a light-emitting element and a pixel circuit, a plurality of first scan lines and second scan lines, a plurality of video signal lines, a controller which controls a scan line drive circuit and a signal line drive circuit, wherein the pixel circuit comprises an output switch, a drive transistor, a capacitance, and a pixel switch, wherein the controller controls a reset operation, a cancellation operation, a correction operation, and a light-emitting operation, and the controller deforms a waveform of a control signal which is supplied from the second scan line in a manner that a time of transitioning the pixel switch from an on-state to an off-state is longer than the time of transitioning by a non-deformed control signal, when writing the video voltage signal in the correction operation. ## Claims ### Claim 1 A display device comprising: a plurality of pixel units which each includes a light-emitting element and a pixel circuit which supplies the light-emitting element with a drive current, the plurality of pixel units being arranged on a substrate in a matrix; a plurality of first scan lines and a plurality of second scan lines each of which is arranged along a row aligned with the pixel unit; a plurality of video signal lines each of which is arranged along a column aligned with the pixel unit; a plurality of reset power source lines each of which is arranged along the row or the column aligned with the pixel unit; a first power source line and a second power source line; a scan line drive circuit which sequentially supplies a control signal to the plurality of first scan lines and the plurality of second scan lines and line-sequentially scans the pixel unit in a row unit; a signal line drive circuit which supplies the video signal line with a video voltage signal in accordance with the line-sequential scanning; and a controller which controls a drive operation of the scan line drive circuit and the signal line drive circuit, wherein the pixel circuit comprises: an output switch whose first terminal is electrically connected to the reset power source line, whose second terminal is electrically connected to the first power source line, and whose control terminal is electrically connected to the first scan line; a drive transistor whose first terminal is electrically connected to an anode of the light-emitting element and whose second terminal is electrically connected to the reset power source line; a capacitance electrically connected between a control terminal and the first terminal of the drive transistor; and a pixel switch whose first terminal is electrically connected to the control terminal of the drive transistor, whose second terminal is electrically connected to the video signal line, whose control terminal is electrically connected to the second scan line, and the video voltage signal is introduced from the video signal line and is maintained to the capacitance, wherein the controller controls: a reset operation which initializes the drive transistor by applying an initialization potential from the video signal line to the control terminal of the drive transistor and by applying a reset potential from the reset power source line to the first terminal of the drive transistor; a cancellation operation which cancels a threshold voltage of the drive transistor by passing a current from the first power source line to the drive transistor, in a state where the initialization potential is applied from the video signal line to the control terminal of the drive transistor; a correction operation which corrects a mobility of the drive transistor and retains a potential according to the video voltage signal in the capacitance by writing the video voltage signal from the video signal line to the control terminal of the drive transistor through the pixel switch and by passing a current from the first power source line to the drive transistor; and a light-emitting operation which supplies the light-emitting element with a drive current according to the video voltage signal from the first power source line through the drive transistor, and the controller deforms a waveform of a control signal which is supplied from the second scan line in a manner that a time of transitioning the pixel switch from an on-state to an off-state is longer than a time of transitioning the pixel switch from the on-state to the off-state by a non-deformed control signal, when writing the video voltage signal in the correction operation. ### Claim 2 (depends on 1) The display device of claim 1, wherein the time of transitioning the pixel switch of the control signal supplied from the second scan line from the on-state to the off-state when writing the video voltage signal in the correction operation is longer than a time of transitioning the pixel from the off-state to the on-state. ### Claim 3 (depends on 1) The display device of claim 1, wherein the time of transitioning the pixel switch of the control signal supplied from the second scan line from the on-state to the off-state in the reset operation or in the cancellation operation is substantially identical with the time of transitioning the pixel from the off-state to the on-state. ### Claim 4 (depends on 1) The display device of claim 1, wherein the controller transitions the control signal supplied from the second scan line from an on-state level once to an intermediate potential level between the on-state level and an off-state level, retains it, and then transitions to the off-state level, when transitioning the pixel switch from the on-state to the off-state in the correction operation. ### Claim 5 (depends on 4) The display device of claim 4, wherein the controller transitions the pixel switch from the on-state to the off-state without retaining to the intermediate potential level in the reset operation and the cancellation operation. ### Claim 6 (depends on 4) The display device of claim 4, further comprising a third power source line which supplies a voltage of an intermediate potential level. ### Claim 7 (depends on 1) The display device of claim 1, wherein the time of transitioning the pixel switch from the on-state to the off-state by the control signal supplied from the second scan line when writing the video voltage signal in the correction operation is longer than a time of transitioning the pixel switch from the on-state to the off-state by the control signal supplied from the second scan line when applying the initialization potential in the reset operation or the cancellation operation. ### Claim 8 A method for driving a display device, wherein the display device comprises: a plurality of pixel units which each includes a light-emitting element and a pixel circuit which supplies the light-emitting element with a drive current, the plurality of pixel units being arranged on a substrate in a matrix; a plurality of first scan lines and a plurality of second scan lines each of which is arranged along a row aligned with the pixel unit; a plurality of video signal lines each of which is arranged along a column aligned with the pixel unit; a plurality of reset power source lines each of which is arranged along the row or the column aligned with the pixel unit; a first power source line and a second power source line; a scan line drive circuit which sequentially supplies a control signal to the plurality of first scan lines and the plurality of second scan lines and line-sequentially scans the pixel unit in a row unit; a signal line drive circuit which supplies the video signal line with a video voltage signal in accordance with the line-sequential scanning; and a controller which controls a drive operation of the scan line drive circuit and the signal line drive circuit, and the pixel circuit comprises: an output switch whose first terminal is electrically connected to the reset power source line, whose second terminal is electrically connected to the first power source line, and whose control terminal is electrically connected to the first scan line; a drive transistor whose first terminal is electrically connected to an anode of the light-emitting element and whose second terminal is electrically connected to the reset power source line; a capacitance electrically connected between a control terminal and the first terminal of the drive transistor; and a pixel switch whose first terminal is electrically connected to the control terminal of the drive transistor, whose second terminal is electrically connected to the video signal line, whose control terminal is electrically connected to the second scan line, and the video voltage signal is introduced from the video signal line and is maintained to the capacitance, and the method for driving comprises: initializing, as a reset operation, the drive transistor by applying an initialization potential from the video signal line to the control terminal of the drive transistor and by applying a reset potential from the reset power source line to the first terminal of the drive transistor; cancelling, as a cancellation operation, a threshold voltage of the drive transistor by passing a current from the first power source line to the drive transistor, in a state where the initialization potential is applied from the video signal line to the control terminal of the drive transistor; correcting, as a correction operation, a mobility of the drive transistor and retains a potential according to the video voltage signal in the capacitance by writing the video voltage signal from the video signal line to the control terminal of the drive transistor through the pixel switch and by passing a current from the first power source line to the drive transistor; and supplying, as a light-emitting operation, the light-emitting element with a drive current according to the video voltage signal from the first power source line through the drive transistor, and the controller deforms a waveform of a control signal which is supplied from the second scan line in a manner that a time of transitioning the pixel switch from an on-state to an off-state is longer than a time of transitioning the pixel switch from the on-state to the off-state by a non-deformed control signal, when writing the video voltage signal in the correction operation. ### Claim 9 (depends on 8) The method for driving the display device of claim 8, wherein the time of transitioning the pixel switch of the control signal supplied from the second scan line from the on-state to the off-state when writing the video voltage signal in the correction operation is longer than a time of transitioning the pixel from the off-state to the on-state. ### Claim 10 (depends on 8) The method for driving the display device of claim 8, wherein the time of transitioning the pixel switch of the control signal supplied from the second scan line from the on-state to the off-state in the reset operation or in the cancellation operation is substantially identical with the time of transitioning the pixel from the off-state to the on-state. ### Claim 11 (depends on 8) The method for driving the display device of claim 8, wherein the control signal supplied from the second scan line from an on-state level is once transitioned to an intermediate potential level between the on-state level and an off-state level, retained, and then transitioned to the off-state level, when transitioning the pixel switch from the on-state to the off-state in the correction operation. ### Claim 12 (depends on 8) The method for driving the display device of claim 8, wherein the pixel switch is transitioned from the on-state to the off-state without retaining to the intermediate potential level in the reset operation and the cancellation operation. ### Claim 13 (depends on 8) The method for driving the display device of claim 8, wherein the time of transitioning the pixel switch from the on-state to the off-state by the control signal supplied from the second scan line when writing the video voltage signal in the correction operation is longer than a time of transitioning the pixel switch from the on-state to the off-state by the control signal supplied from the second scan line when applying the initialization potential in the reset operation or the cancellation operation.