# US 12,007,656 B2 · Display device

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- Number: US 12,007,656 B2
- Document ID: US12007656B2
- Status: Granted
- Kind: B2
- Application number: 17/980,674
- Filed: 2022-11-04
- Published: 2023-02-23
- Granted: 2024-06-11
- Earliest claimed: 2010-02-11
- Assignees: Semiconductor Energy Laboratory Co., Ltd.
- Applicants: Semiconductor Energy Laboratory Co., Ltd.
- Inventors: Hajime Kimura; Atsushi Umezaki
- Web page: https://patentgrep.com/patent/US12007656B2

## CPC

- G02F 1/13624: {having more than one switching element per pixel}
- G02F 1/136259: {Repairing; Defects}
- G02F 1/136286: {Wiring, e.g. gate line, drain line}
- G02F 1/1368: in which the switching element is a three-electrode device {(G02F1/136277 takes precedence)}
- G09G 3/006: {Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays (testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309)}
- G09G 3/344: {based on particles moving in a fluid or in a gas, e.g. electrophoretic devices (electrophoretic devices per se G02F1/167)}
- G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)}
- G09G 3/3651: {using multistable liquid crystals, e.g. ferroelectric liquid crystals}
- H10D 30/6755: {Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate}
- H10D 86/423: {comprising semiconductor materials not belonging to the Group IV, e.g. InGaZnO}
- H10D 86/441: {Interconnections, e.g. scanning lines}
- H10D 86/481: {integrated with passive devices, e.g. auxiliary capacitors}
- H10D 86/60: wherein the TFTs are in active matrices
- G02F 1/133302: {Rigid substrates, e.g. inorganic substrates}
- G02F 1/133345: {Insulating layers (G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence)}
- G02F 1/1339: Gaskets; Spacers; Sealing of cells
- G02F 1/134309: {characterised by their geometrical arrangement}
- G02F 1/13439: {characterised by their electrical, optical, physical properties; materials therefor; method of making}
- G02F 1/136254: {Checking; Testing}
- G02F 1/167: by electrophoresis
- G09G 3/2003: {Display of colours (specific for liquid crystal displays G09G3/3607)}
- G09G 3/3208: organic, e.g. using organic light-emitting diodes [OLED]
- G09G 2230/00: Details of flat display driving waveforms
- G09G 2310/0251: Precharge or discharge of pixel before applying new pixel voltage
- G09G 2320/0214: with crosstalk due to leakage current of pixel switch in active matrix panels
- H10D 30/673: {characterised by the shapes, relative sizes or dispositions of the gate electrodes}
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- 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

An object is to provide a display device that performs accurate display. A circuit is formed using a transistor that includes an oxide semiconductor and has a low off-state current. A precharge circuit or an inspection circuit is formed in addition to a pixel circuit. The off-state current is low because the oxide semiconductor is used. Thus, it is not likely that a signal or voltage is leaked in the precharge circuit or the inspection circuit to cause defective display. As a result, a display device that performs accurate display can be provided.

## Claims

### Claim 1

A display device comprising:
a pixel portion including a plurality of first transistors; and
a circuit including a plurality of second transistors, the circuit being configured to inspect whether the plurality of the first transistors normally operate or not,
wherein channel formation regions of the plurality of the first transistors and the plurality of the second transistors include oxide semiconductor,
wherein gate electrodes of the plurality of the second transistors are electrically connected to a first wiring,
wherein the first wiring includes at least three lines, and signals are configured to be supplied to the at least three lines at different timings,
wherein source or drain electrodes of the plurality of the second transistors are electrically connected to a second wiring,
wherein a channel width of the plurality of the second transistors is larger than a channel width of the plurality of the first transistors, and
wherein an off-state current per channel width of 1 μm of the plurality of the first transistors and the plurality of the second transistors is 100 aA or less.

### Claim 2 (depends on 1)

The display device according to claim 1, wherein each of the first wiring and the second wiring is in a floating state.

### Claim 3 (depends on 1)

The display device according to claim 1, wherein the first wiring and the second wiring extend in parallel with each other.