Semiconductor device, display device, and electronic device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorHajime Kimura
Life of this patent
Estimating the term…
Abstract
A display device includes a load, a transistor for controlling a current value supplied to the load, a capacitor, a first wiring, a second wiring, and first to fourth switches. Variations in the current value caused by variations in the threshold voltage of the transistor can be suppressed through the steps of: (1) holding the threshold voltage of the transistor in the storage capacitor, (2) inputting a potential in accordance with a video signal, and (3) holding a voltage that is the sum of the threshold voltage and the potential in accordance with the video signal, in the storage capacitor. Accordingly, a desired current can be supplied to the load such as a light emitting element.
Claims20
A semiconductor device comprising:
- a transistor comprising a semiconductor layer, a gate electrode, a source electrode, and a drain electrode, wherein each of the source electrode and the drain electrode overlaps with the semiconductor layer;
- a first switch wherein the gate electrode of the transistor is electrically connected to a terminal of the first switch;
- a second switch wherein the gate electrode of the transistor is electrically connected to a terminal of the second switch;
- a first electrode electrically connected to one of the source electrode and the drain electrode of the transistor;
- and
- a capacitor,
- wherein a first terminal of the capacitor is electrically connected to the first electrode and the one of the source electrode and the drain electrode of the transistor,
- wherein a second terminal of the capacitor is electrically connected to the gate electrode of the transistor, and
- wherein an area of the one of the source electrode and the drain electrode of the transistor is larger than an area of the other of the source electrode and the drain electrode of the transistor.
A semiconductor device comprising:
- a first n-channel transistor comprising a semiconductor layer, a gate electrode, a source electrode, and a drain electrode, wherein each of the source electrode and the drain electrode overlaps with the semiconductor layer;
- a second n-channel transistor wherein the gate electrode of the first n-channel transistor is electrically connected to a terminal of the second n-channel transistor;
- a third n-channel transistor wherein the gate electrode of the first n-channel transistor is electrically connected to a terminal of the third n-channel transistor;
- an anode electrically connected to one of the source electrode and the drain electrode of the first n-channel transistor;
- a cathode opposed to the anode with a light emitting layer therebetween;
- and
- a capacitor,
- wherein a first terminal of the capacitor is electrically connected to the anode and the one of the source electrode and the drain electrode of the first n-channel transistor,
- wherein a second terminal of the capacitor is electrically connected to the gate electrode of the first n-channel transistor, and
- wherein an area of the one of the source electrode and the drain electrode of the first re-channel transistor is larger than an area of the other of the source electrode and the drain electrode of the first n-channel transistor.
Dependencies are inferred from the claim text.