PORTABLE ELECTRONIC DEVICE

• US 20110176263A1
• Filed: 01/13/2011
• Published: 07/21/2011
• Est. Priority Date: 01/20/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: YAMAZAKI, Shunpei, KOYAMA, Jun
• Granted Patent: US 8,830,661 B2
• Time in Patent Office: Days
• US Class Current: 361/679.01
• CPC Class Codes: G06F 1/1626 with a single-body enclosure integrating a flat display, e.g. Personal Digital Assistants [PDAs]
• CPC Class Codes: G06F 1/1635 Details related to the integration of battery packs and other power supplies such as fuel cells or integrated AC adapter
• CPC Class Codes: G06F 1/1637 Details related to the display arrangement, including those related to the mounting of the display in the housing
• CPC Class Codes: G06F 1/263 Arrangements for using multiple switchable power supplies, e.g. battery and AC G06F1/30 takes precedence
• CPC Class Codes: G11C 5/063 Voltage and signal distribution in integrated semi-conductor memory access lines, e.g. word-line, bit-line, cross-over resistance, propagation delay
• CPC Class Codes: H01L 29/786 Thin film transistors, i.e. transistors with a channel being at least partly a thin film transistors having only the source or the drain region on an insulator layer H01L29/0653; thin film FinFETs H01L29/785

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.

Claims

1. A portable electronic device comprising:

a display portion including a transistor, the transistor comprising first oxide semiconductor;

a power source portion comprising a rechargeable battery capable of charge by contactless charge; and

a signal processing portion comprising a nonvolatile semiconductor memory device.

2. The portable electronic device according to claim 1, wherein the display portion comprises a reflective liquid crystal display device.

3. The portable electronic device according to claim 1, wherein electric power stored in the rechargeable battery is used in the display portion and the signal processing portion.

4. The portable electronic device according to claim 1, wherein the power source portion comprises a solar cell.

5. The portable electronic device according to claim 1, wherein the first oxide semiconductor is intrinsic or substantially intrinsic.

6. The portable electronic device according to claim 1, wherein the first oxide semiconductor has an off-state current of lower than or equal to 1 aA/μ

m.

7. The portable electronic device according to claim 1, wherein the portable electronic device is an e-book reader.

8. A portable electronic device comprising:

a display portion including a first transistor, the first transistor comprising first oxide semiconductor;

a power source portion comprising a rechargeable battery capable of charge by contactless charge; and

a signal processing portion comprising a nonvolatile semiconductor memory device, the nonvolatile semiconductor memory device comprising;

a second transistor;

a third transistor;

a third transistor capacitor; and

first to fifth wirings,

wherein a first terminal of the second transistor is electrically connected to the first wiring, a second terminal of the second transistor is electrically connected to the second wiring, and a gate of the second transistor is electrically connected to a first terminal of the third transistor or one electrode of the capacitor,

wherein a second terminal of the third transistor is electrically connected to the third wiring, and a gate of the third transistor is electrically connected to the fourth wiring, and

wherein the other electrode of the capacitor is electrically connected to the fifth wiring.

9. The portable electronic device according to claim 8, wherein the third transistor comprises second oxide semiconductor.

10. The portable electronic device according to claim 9, wherein the second oxide semiconductor is a same as the first oxide semiconductor.

11. The portable electronic device according to claim 9, wherein the second oxide semiconductor is different from the first oxide semiconductor.

12. The portable electronic device according to claim 9, wherein the second oxide semiconductor is intrinsic or substantially intrinsic.

13. The portable electronic device according to claim 9, wherein the second oxide semiconductor has an off-state current of lower than or equal to 1 aA/μ

m.

14. The portable electronic device according to claim 8, wherein the display portion comprises a reflective liquid crystal display device.

15. The portable electronic device according to claim 8, wherein electric power stored in the rechargeable battery is used in the display portion and the signal processing portion.

16. The portable electronic device according to claim 8, wherein the power source portion comprises a solar cell.

17. The portable electronic device according to claim 8, wherein the first oxide semiconductor is intrinsic or substantially intrinsic.

18. The portable electronic device according to claim 8, wherein the first oxide semiconductor has an off-state current of lower than or equal to 1 aA/μ

m.

19. The portable electronic device according to claim 8, wherein the portable electronic device is an e-book reader.