# US 11,114,029 B2 · Image display device having a drive transistor with a channel length longer than a channel length of individual switching transistors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,114,029 B2 - Document ID: US11114029B2 - Status: Granted - Kind: B2 - Application number: 16/893,555 - Filed: 2020-06-05 - Published: 2020-12-24 - Granted: 2021-09-07 - 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/US11114029B2 ## 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 plurality of scanning lines arranged in rows; a plurality of signal lines arranged in columns; a scanner part configured to supply a control signal to the plurality of scanning lines; a plurality of pixel circuits arranged in a matrix, respective ones of the plurality of pixel circuits connected to a corresponding one of the plurality of scanning lines and a corresponding one of the plurality of signal lines, wherein respective ones of the plurality of pixel circuits include a pixel capacitor, a sampling transistor, a drive transistor having a first channel length, a first switching transistor having a second channel length, and a light emitting device, and the first channel length is longer than the second channel length. ### Claim 2 (depends on 1) The image display device according to claim 1, wherein respective ones of the plurality of pixel circuits further include a second switching transistor having a third channel length, and the first channel length is longer than the third channel length. ### Claim 3 (depends on 2) The image display device according to claim 2, wherein respective ones of the plurality of pixel circuits further include a third switching transistor having a fourth channel length, and the first channel length is longer than the fourth channel length. ### Claim 4 (depends on 3) The image display device according to claim 3, wherein a gate of the sampling transistor is connected to a first scanning line of the plurality of scanning lines, a gate of the first switching transistor is connected to a second scanning line of the plurality of scanning lines, a gate of the second switching transistor is connected to a third scanning line of the plurality of scanning lines, and a gate of the third switching transistor is connected to a fourth scanning line of the plurality of scanning lines. ### Claim 5 (depends on 3) The image display device according to claim 3, wherein the first switching transistor is configured to selectively supply a first predetermined potential to the pixel capacitor, the second switching transistor is configured to selectively supply a second predetermined potential to an electrode of the light emitting device, and the third switching transistor is configured to selectively supply a third predetermined potential to the drive transistor. ### Claim 6 (depends on 1) The image display device according to claim 1, wherein the scanner part includes a scanner transistor having a fifth channel length, and the first channel length is longer than the fifth channel length. ### Claim 7 (depends on 1) The image display device according to claim 1, wherein the first channel length is at least 10 μm. ### Claim 8 (depends on 7) The image display device according to claim 7, wherein the first channel length is from 15 μm to 20 μm. ### Claim 9 (depends on 1) The image display device according to claim 1, wherein the drive transistor is formed by a low temperature polysilicon process. ### Claim 10 (depends on 1) The image display device according to claim 1, wherein the drive transistor and the sampling transistor respectively include a low temperature polysilicon having a plurality of grains. ### Claim 11 An electronic appliance, comprising: an image display device including: a plurality of scanning lines arranged in rows, a plurality of signal lines arranged in columns, a scanner part configured to supply a control signal to the plurality of scanning lines, a plurality of pixel circuits arranged in a matrix, respective ones of the plurality of pixel circuits connected to a corresponding one of the plurality of scanning lines and a corresponding one of the plurality of signal lines, wherein respective ones of the plurality of pixel circuits include a pixel capacitor, a sampling transistor, a drive transistor having a first channel length, a first switching transistor having a second channel length, and a light emitting device, and the first channel length is longer than the second channel length. ### Claim 12 (depends on 11) The electronic appliance according to claim 11, wherein respective ones of the plurality of pixel circuits further include a second switching transistor having a third channel length, and the first channel length is longer than the third channel length. ### Claim 13 (depends on 12) The electronic appliance according to claim 12, wherein respective ones of the plurality of pixel circuits further include a third switching transistor having a fourth channel length, and the first channel length is longer than the fourth channel length. ### Claim 14 (depends on 13) The electronic appliance according to claim 13, wherein a gate of the sampling transistor is connected to a first scanning line of the plurality of scanning lines, a gate of the first switching transistor is connected to a second scanning line of the plurality of scanning lines, a gate of the second switching transistor is connected to a third scanning line of the plurality of scanning lines, and a gate of the third switching transistor is connected to a fourth scanning line of the plurality of scanning lines. ### Claim 15 (depends on 13) The electronic appliance according to claim 13, wherein the first switching transistor is configured to selectively supply a first predetermined potential to the pixel capacitor, the second switching transistor is configured to selectively supply a second predetermined potential to an electrode of the light emitting device, and the third switching transistor is configured to selectively supply a third predetermined potential to the drive transistor. ### Claim 16 (depends on 11) The electronic appliance according to claim 11, wherein the scanner part includes a scanner transistor having a fifth channel length, and the first channel length is longer than the fifth channel length. ### Claim 17 (depends on 11) The electronic appliance according to claim 11, wherein the first channel length is at least 10 μm. ### Claim 18 (depends on 17) The electronic appliance according to claim 17, wherein the first channel length is from 15 μm to 20 μm. ### Claim 19 (depends on 11) The electronic appliance according to claim 11, wherein the drive transistor is formed by a low temperature polysilicon process. ### Claim 20 (depends on 11) The electronic appliance according to claim 11, wherein the drive transistor and the sampling transistor respectively include a low temperature polysilicon having a plurality of grains.