# US 12,190,812 B2 · Display device comprising a first transistor, a second transistor, a third transistor, and a light-emitting element

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- Number: US 12,190,812 B2
- Document ID: US12190812B2
- Status: Granted
- Kind: B2
- Application number: 18/283,844
- Filed: 2022-04-11
- Published: 2024-05-23
- Granted: 2025-01-07
- Earliest claimed: 2021-04-22
- Assignees: Semiconductor Energy Laboratory Co., Ltd.
- Applicants: Semiconductor Energy Laboratory Co., Ltd.
- Inventors: Shunpei Yamazaki; Kenichi Okazaki; Koji Kusunoki
- Web page: https://patentgrep.com/patent/US12190812B2

## CPC

- H10K 50/00: Organic light-emitting devices (integrated devices or assemblies of multiple devices H10K59/00, H10K65/00; organic semiconductor lasers H01S5/36)
- G09F 9/30: in which the desired character or characters are formed by combining individual elements (panels comprising a number of electrodes in a single cell controlling light arriving from an independent light source, e.g. electro-optical or magneto-optical cell, G02F1/00)
- G09G 3/20: for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix {no fixed position being assigned to or needed to be assigned to the individual characters or partial characters}
- G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element
- H10D 30/67: Thin-film transistors [TFT] {(Stacked nanowire, nanosheet or nanoribbon FETs H10D30/501)}
- H10K 59/00: Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K 59/1213: {the pixel elements being TFTs}
- G09G 2300/0426: Layout of electrodes and connections
- G09G 2300/0452: Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
- 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 2320/0233: Improving the luminance or brightness uniformity across the screen
- G09G 2330/021: Power management, e.g. power saving
- H10K 59/871: {Self-supporting sealing arrangements}
- H10K 59/873: {Encapsulations}
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- G09F: DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
- 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

## Abstract

A display device that has high display quality is provided. A highly reliable display device is provided. A display device with low power consumption is provided. A light-emitting element is electrically connected to one of a source and a drain of a first transistor. The other of the source and the drain of the first transistor is electrically connected to one of a source and a drain of a second transistor. A gate electrode of the second transistor is electrically connected to one of a source and a drain of a third transistor. A semiconductor layer of the second transistor and a semiconductor layer of the third transistor each include indium, zinc and a third metal. The ratio of the number of indium atoms to the total number of the indium atoms, zinc atoms, and atoms of the third metal in the semiconductor layer of the second transistor is higher than or equal to 30 atomic % and lower than or equal to 100 atomic %. The second transistor has a function of controlling the amount of light emission of the light-emitting element.

## Claims

### Claim 1

A display device comprising a first transistor, a second transistor, a third transistor, and a light-emitting element,
wherein the light-emitting element is electrically connected to one of a source and a drain of the first transistor,
wherein the other of the source and the drain of the first transistor is electrically connected to one of a source and a drain of the second transistor,
wherein a gate electrode of the second transistor is electrically connected to one of a source and a drain of the third transistor,
wherein a semiconductor layer of the second transistor comprises indium, zinc, and an element M,
wherein the element M is one or more kinds selected from gallium, aluminum, yttrium, tin, silicon, boron, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and cobalt,
wherein a semiconductor layer of the third transistor comprises indium, zinc and the element M,
wherein a ratio of the number of indium atoms to a total number of the indium atoms, zinc atoms, and atoms of the element M in the semiconductor layer of the second transistor is higher than or equal to 30 atomic % and lower than or equal to 100 atomic %,
wherein a ratio of the number of atoms of the element M to a total number of indium atoms, zinc atoms, and the atoms of the element M in the semiconductor layer of the third transistor is higher than that in the semiconductor layer of the second transistor, and
wherein the second transistor is configured to control the amount of light emission of the light-emitting element.

### Claim 2 (depends on 1)

The display device according to claim 1,
wherein the other of the source and the drain of the third transistor is electrically connected to the other of the source and the drain of the second transistor, and
wherein the ratio of the number of the indium atoms to the total number of the indium atoms, the zinc atoms, and the atoms of the element M in the semiconductor layer of the second transistor is higher than that in the semiconductor layer of the third transistor.

### Claim 3 (depends on 1)

The display device according to claim 1,
wherein the ratio of the number of the atoms of the element M to the total number of atoms of contained metal elements in the semiconductor layer of the third transistor is higher than or equal to 20 atomic % and lower than or equal to 60 atomic %.

### Claim 4 (depends on 1)

The display device according to claim 1, further comprising a fourth transistor, a fifth transistor, a first wiring, a capacitor, and a driver circuit,
wherein one of a source and a drain of the fourth transistor is electrically connected to the one of the source and the drain of the second transistor,
wherein one of a source and a drain of the fifth transistor is electrically connected to the other of the source and the drain of the second transistor,
wherein the other of the source and the drain of the fourth transistor is electrically connected to the first wiring,
wherein a first electrode of the capacitor is electrically connected to the one of the source and the drain of the first transistor,
wherein a second electrode of the capacitor is electrically connected to a gate of the second transistor, and
wherein the first wiring is configured to supply a video signal output from the driver circuit to the other of the source and the drain of the fourth transistor.

### Claim 5 (depends on 4)

The display device according to claim 4,
wherein the display device is configured to write a potential to the gate of the second transistor by turning on the second transistor, the third transistor, and the fourth transistor and turning off the first transistor and the fifth transistor, and
wherein the display device is configured to retain the written potential by turning off the third transistor and the fourth transistor after the potential is written.

### Claim 6 (depends on 4)

The display device according to claim 4,
wherein the display device is configured to write a potential to the gate of the second transistor by turning on the second transistor, the third transistor, and the fourth transistor and turning off the first transistor and the fifth transistor,
wherein the display device is configured to retain the written potential by turning off the third transistor and the fourth transistor after the potential is written, and
wherein the display device is configured to control the amount of light emission of the light-emitting element by turning on the first transistor, the second transistor, and the fifth transistor and flowing current through the light-emitting element, after the potential is retained.