# US 10,310,348 B2 · Liquid crystal display device and electronic apparatus having the same

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- Number: US 10,310,348 B2
- Document ID: US10310348B2
- Status: Granted
- Kind: B2
- Application number: 16/109,886
- Filed: 2018-08-23
- Published: 2018-12-20
- Granted: 2019-06-04
- Earliest claimed: 2009-10-16
- Assignees: Semiconductor Energy Laboratory Co., Ltd.
- Applicants: Semiconductor Energy Laboratory Co., Ltd.
- Inventors: Shunpei Yamazaki; Jun Koyama; Hiroyuki Miyake; Masashi Tsubuku; Kosei Noda
- Web page: https://patentgrep.com/patent/US10310348B2

## CPC

- G02F 1/1368: in which the switching element is a three-electrode device {(G02F1/136277 takes precedence)}
- G09G 3/3611: {Control of matrices with row and column drivers}
- G09G 3/3674: {Details of drivers for scan electrodes}
- G09G 3/3677: {suitable for active matrices only}
- 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 86/60: wherein the TFTs are in active matrices
- G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)}
- G09G 5/18: Timing circuits for raster scan displays (specially adapted for television H04N {; synchronisation between the display unit and other display units, videodisc player G09G5/12})
- G09G 2310/0286: Details of a shift registers arranged for use in a driving circuit
- G09G 2320/103: Detection of image changes, e.g. determination of an index representative of the image change
- G09G 2330/021: Power management, e.g. power saving
- G09G 2330/022: in absence of operation, e.g. no data being entered during a predetermined time
- G09G 2330/027: Arrangements or methods related to powering off a display
- 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

A liquid crystal display device includes: a driver circuit portion; a pixel portion; a signal generation circuit for generating a control signal for driving the driver circuit portion and an image signal which is supplied to the pixel portion; a memory circuit; a comparison circuit for detecting a difference of image signals for a series of frame periods among image signals stored for respective frame periods in the memory circuit; a selection circuit which selects and outputs the image signals for the series of frame periods when the difference is detected in the comparison circuit; and a display control circuit which supplies the control signal and the image signals output from the selection circuit, to the driver circuit portion when the difference is detected in the comparison circuit, and stops supplying the control signal to the driver circuit portion when the difference is not detected in the comparison circuit.

## Claims

### Claim 1

A liquid crystal display device comprising:
a pixel portion comprising a transistor and a liquid crystal element; and
a driver circuit portion electrically connected to the pixel portion,
wherein a channel formation region of the transistor comprises an oxide semiconductor layer,
wherein an off-state current per micrometer of a channel width of the transistor is 1×10−16 A/μm or lower at a drain voltage of 6V and a gate voltage of −5V or −10V, and
wherein supply of a control signal to the driver circuit portion is stopped when a still image is displayed on the pixel portion.

### Claim 2 (depends on 1)

The liquid crystal display device according to claim 1, wherein the oxide semiconductor layer comprises indium, gallium, and zinc.

### Claim 3 (depends on 1)

The liquid crystal display device according to claim 1, wherein the oxide semiconductor layer comprises a crystal.

### Claim 4 (depends on 1)

The liquid crystal display device according to claim 1, wherein the oxide semiconductor layer has a hydrogen concentration of 1×1016/cm3 or less which is detected by secondary ion mass spectrometry.

### Claim 5 (depends on 1)

The liquid crystal display device according to claim 1, wherein the oxide semiconductor layer has a carrier density which is less than 1×1014/cm3.

### Claim 6 (depends on 1)

The liquid crystal display device according to claim 1, wherein an off-state resistivity of the transistor is 1×109 Ωm or more.

### Claim 7 (depends on 1)

The liquid crystal display device according to claim 1, wherein the control signal is a high power supply potential, a low power supply potential, a clock signal, a start pulse signal, or a reset signal.

### Claim 8 (depends on 1)

An electronic apparatus comprising the liquid crystal display device according to claim 1.