Portable electronic device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei YAMAZAKI, Jun KOYAMA
Life of this patent
Estimating the term…
Abstract
A portable electronic device that can operate even when electric power supplied through contactless charge by electromagnetic induction is low is provided. The portable electronic device includes a reflective liquid crystal display which includes a transistor including an oxide semiconductor, a power source portion which includes a rechargeable battery capable of charge by contactless charge, and a signal processing portion which includes a nonvolatile semiconductor memory device. In the portable electronic device, electric power stored in the rechargeable battery is used in the reflective liquid crystal display and the signal processing portion.
Claims24
A portable electronic device comprising:
- a display portion including a first transistor;
- a power source portion comprising a rechargeable battery capable of charge by contactless charge;
- and
- a signal processing portion comprising a semiconductor memory device,
- wherein the first transistor comprises:
- an oxide semiconductor layer over a substrate;
- source and drain electrodes on the oxide semiconductor layer;
- a gate insulating film on the source and drain electrodes and the oxide semiconductor layer;
- source and drain wirings electrically connected to the source and drain electrodes via openings of the gate insulating film, respectively;
- and
- a gate electrode on the gate insulating film,
- wherein the oxide semiconductor layer has an off-state current of lower than or equal to 1 aA/μm when a voltage between the source and drain electrodes is 1V.
A portable electronic device comprising:
- a display portion including a first transistor;
- a power source portion comprising a rechargeable battery capable of charge by contactless charge;
- and
- a signal processing portion comprising a semiconductor memory, the semiconductor memory comprising a second transistor,
- wherein each of the first and second transistors comprises:
- an oxide semiconductor layer over a substrate;
- source and drain electrodes on the oxide semiconductor layer;
- a gate insulating film on the source and drain electrodes and the oxide semiconductor layer;
- source and drain wirings electrically connected to the source and drain electrodes via openings of the gate insulating film, respectively;
- and
- a gate electrode on the gate insulating film,
- wherein the oxide semiconductor layer has an off-state current of lower than or equal to 1 aA/μm when a voltage between the source and drain electrodes is 1V.
A portable electronic device comprising:
- a display portion including a first transistor;
- a power source portion comprising a rechargeable battery capable of charge by contactless charge;
- and
- a signal processing portion comprising a semiconductor memory, the semiconductor memory comprising a second transistor and a third transistor,
- wherein each of the first and second transistors comprises:
- an oxide semiconductor layer over a substrate;
- source and drain electrodes on the oxide semiconductor layer;
- a gate insulating film on the source and drain electrodes and the oxide semiconductor layer;
- source and drain wirings electrically connected to the source and drain electrodes via openings of the gate insulating film, respectively;
- and
- a gate electrode on the gate insulating film,
- wherein the oxide semiconductor layer has an off-state current of lower than or equal to 1 aA/μm when a voltage between the source and drain electrodes is 1V, and
- wherein the third transistor comprises crystalline silicon.
Dependencies are inferred from the claim text.