# US 2019/0172393 A1 · Image display device and electronic appliance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0172393 A1 - Document ID: US20190172393A1 - Status: Published application - Kind: A1 - Application number: 16/268,986 - Filed: 2019-02-06 - Published: 2019-06-06 - Earliest claimed: 2006-08-18 - Assignees: Sony Corporation - Applicants: Sony Corporation - Inventors: Junichi Yamashita; Yutaka Mitomi; Tetsuo Minami; Takao Tanikame - Web page: https://patentgrep.com/patent/US20190172393A1 ## CPC - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - H10D 30/6732: {Bottom-gate only TFTs} - H10D 30/674: {characterised by the active materials} - H10D 30/6745: {Polycrystalline or microcrystalline silicon} - H10D 30/6757: {characterised by the structure of the channel, e.g. transverse or longitudinal shape or doping profile (TFTs having channel structures for preventing kink or snapback effects H10D30/6708; TFTs having lightly-doped source or drain extensions H10D30/6715)} - H10K 59/1213: {the pixel elements being TFTs} - H10K 59/1216: {the pixel elements being capacitors} - H10K 59/131: Interconnections, e.g. wiring lines or terminals - 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 2320/0233: Improving the luminance or brightness uniformity across the screen - G09G 2320/043: Preventing or counteracting the effects of ageing - G09G 2320/0626: for control of overall brightness - 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) - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES ## Abstract An image display device includes: a pixel array part formed of first to fourth scanning lines arranged in rows, signal lines arranged in columns, pixel circuits in a matrix connected to the scanning lines and signal lines, and a plurality of power source lines which supplies first to third potentials necessary for the operations of pixel circuit; a signal part which supplies a video signal to the signal lines; and a scanner part which supplies a control signal to the first to fourth scanning lines, and in turn scans the pixel circuit for every row, wherein the pixel circuits include a sampling transistor, a drive transistor, first to third switching transistors, a pixel capacitance, and a light emitting device, and a channel length of the drive transistor is made longer than a channel length of the switching transistors to suppress fluctuations in threshold voltage. ## Claims ### Claim 1 An image display device comprising: a pixel array part comprising: a first scanning line extending along a row direction; a second scanning line extending along the row direction; a third scanning line extending along the row direction; a fourth scanning line extending along the row direction; a signal line extending along a column direction and configured to supply a video signal; a first voltage line; a second voltage line; a third voltage line; a sampling transistor; a first switching transistor; a second switching transistor; a third switching transistor; a light emitting device; and a pixel capacitor, wherein the first switching transistor is connected between the first voltage line and the driving transistor, the second switching transistor is connected between the second voltage line and the light emitting device, the third switching transistor is connected between the third voltage line and the pixel capacitor, and is connected between the third voltage line and a control terminal of the drive transistor, the first scanning line is connected to a control terminal of the first switching transistor, the second scanning line is connected to a control terminal of the second switching transistor, the third scanning line is connected to a control terminal of the sampling transistor, the fourth scanning line is connected to a control terminal of the third switching transistor, the signal line is connected to the sampling transistor, and a channel length of the drive transistor is longer than a channel length of the first switching transistor, is longer than a channel length of the second switching transistor, and is longer than a channel length of the third switching transistor. ### Claim 2 (depends on 1) The image display device according to claim 1, wherein the drive transistor includes a polycrystalline silicon film. ### Claim 3 (depends on 1) The image display device according to claim 1, wherein the channel length of the drive transistor is 10 μm or greater. ### Claim 4 (depends on 1) The image display device according to claim 1, wherein the channel length of the drive transistor is from 15 μm to 20 μm. ### Claim 5 (depends on 1) The image display device according to claim 1, wherein the sampling transistor is configured to supply a signal potential from the signal line to the pixel capacitor. ### Claim 6 (depends on 1) The image display device according to claim 1, wherein the third switching transistor is directly connected between the third voltage line and the pixel capacitor. ### Claim 7 (depends on 1) The image display device according to claim 1 wherein the channel length of the drive transistor is set such that during a light emission period, a gate potential of the drive transistor and a source potential of the drive transistor rise together so that a voltage difference between the gate potential and the source potential remains constant throughout the light emission period. ### Claim 8 An image display device comprising: a first scanning line extending along a row direction; a second scanning line extending along the row direction; a third scanning line extending along the row direction; a fourth scanning line extending along the row direction; a signal line extending along a column direction and configured to supply a video signal; a first voltage line; a second voltage line; a third voltage line; and a pixel circuit connected to the first scanning line, the second scanning line, the third scanning line, the fourth scanning line, the signal line, the first voltage line, and the second voltage line, and the third voltage line, wherein the pixel circuit includes a sampling transistor, a drive transistor, a pixel capacitor, a light emitting device, a first switching transistor, a second switching transistor, and a third switching transistor, the first switching transistor is connected between the first voltage line and the driving transistor, the second switching transistor is connected between the second voltage line and the light emitting device, the third switching transistor is connected between the third voltage line and the pixel capacitor, and is connected between the third voltage line and a control terminal of the drive transistor, the first scanning line is connected to a control terminal of the first switching transistor, the second scanning line is connected to a control terminal of the second switching transistor, the third scanning line is connected to a control terminal of the sampling transistor, the fourth scanning line is connected to a control terminal of the third switching transistor and a channel length of the drive transistor is longer than a channel length of the first switching transistor, is longer than a channel length of the second switching transistor, and is longer than a channel length of the third switching transistor. ### Claim 9 (depends on 8) The image display device according to claim 8, wherein the drive transistor includes a polycrystalline silicon film. ### Claim 10 (depends on 8) The image display device according to claim 8, wherein the channel length of the drive transistor is 10 μm or greater. ### Claim 11 (depends on 8) The image display device according to claim 8, wherein the channel length of the drive transistor is from 15 μm to 20 μm. ### Claim 12 (depends on 8) The image display device according to claim 8, wherein the sampling transistor is configured to supply a signal potential from the signal line to the pixel capacitor. ### Claim 13 (depends on 8) The image display device according to claim 8, wherein the third switching transistor directly connected between a third the third voltage line and the pixel capacitor. ### Claim 14 (depends on 8) The image display device according to claim 8, wherein the first switching transistor is turned on at a timing prior to the light emission period so as to apply a bias to the light emitting device. ### Claim 15 (depends on 8) The image display device according to claim 8, wherein an increase of the source potential of the driving transistor is caused by a current through the driving transistor from the first voltage line to a source terminal of the driving transistor. ### Claim 16 (depends on 8) The image display device according to claim 8, wherein a gate potential of the drive transistor increases in response to the increase of the source potential of the driving transistor so that a voltage difference between the gate potential and the source potential remains constant throughout the light emission period. ### Claim 17 (depends on 1) The image display device according to claim 1, further comprising a scanner part configured to supply a first control signal to the first scanning line, a second control signal to the second scanning line, and a third control signal to the third scanning line. ### Claim 18 (depends on 17) The image display device according to claim 17, wherein the pixel circuit and the scanner part are disposed on a substrate. ### Claim 19 (depends on 17) The image display device according to claim 17, wherein the channel length of the drive transistor is longer than a channel length of a particular one of a plurality of transistors in the scanner part. ### Claim 20 (depends on 17) The image display device according to claim 17, wherein the channel length of the drive transistor is longer than respective channel lengths of a plurality of transistors in the scanner part. ### Claim 21 (depends on 1) The image display device according to claim 1, wherein the sampling transistor is directly connected between the signal line and the pixel capacitor. ### Claim 22 (depends on 1) The image display device according to claim 1, wherein the driving transistor is directly connected between the first switching transistor and the light emitting device. ### Claim 23 (depends on 8) The image display device according to claim 8, further comprising a scanner part configured to supply a first control signal to the first scanning line, a second control signal to the second scanning line, a third control signal to the third scanning line, and a fourth control signal to the fourth scanning line. ### Claim 24 (depends on 23) The image display device according to claim 23, wherein the pixel circuit and the scanner part are disposed on a substrate. ### Claim 25 (depends on 23) The image display device according to claim 23, wherein the channel length of the drive transistor is longer than a channel length of a particular one of a plurality of transistors in the scanner part. ### Claim 26 (depends on 23) The image display device according to claim 23, wherein the channel length of the drive transistor is longer than respective channel lengths of a plurality of transistors in the scanner part.