SEMICONDUCTOR DEVICE, DISPLAY DEVICE AND ELECTRONIC DEVICE EQUIPPED WITH THE SEMICONDUCTOR DEVICE

• US 20070035340A1
• Filed: 08/07/2006
• Published: 02/15/2007
• Est. Priority Date: 08/12/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: KIMURA, Hajime
• Granted Patent: US 7,859,488 B2
• Time in Patent Office: Days
• US Class Current: 327/524
• CPC Class Codes: G09G 2300/0417 Special arrangements specific to the use of low carrier mobility technology
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 2310/0248 Precharge or discharge of column electrodes before or after applying exact column voltages
• CPC Class Codes: G09G 2310/0262 The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2320/0223 Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 3/325 the data current flowing through the driving transistor during a setting phase, e.g. by using a switch for connecting the driving transistor to the data driver
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 50/824 combined with auxiliary electrodes
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals
• CPC Class Codes: H10K 59/80522 combined with auxiliary electrodes

Abstract

The present invention provides a semiconductor device which can prevent a current from flowing into a display element at a signal writing operation, without increasing power consumption and without changing a potential of a power supply for supplying a current to a load in each row. When a predetermined current is supplied to a transistor to set a gate-source voltage of the transistor, a potential of a gate terminal of the transistor is adjusted so as to prevent a current from flowing into a load which is connected to a source terminal of the transistor. Thus, a potential of a wire connected to the gate terminal of the transistor is made different from that of a wire connected to a drain terminal of the transistor. At that time, an operation of a transistor is shifted so as to allow a large amount of current to flow, and influences by intersection capacitance parasitic to a wire or the like or wire resistance are hardly caused, and a set operation is conducted quickly.

Claims

1. A semiconductor device comprising:

a first wire;

a second wire;

a third wire;

a first switch;

a second switch;

a first transistor, wherein a first terminal of the first transistor is electrically connected to the first wire, and a gate terminal of the first transistor is electrically connected to the second wire via the first switch;

a second transistor, wherein a first terminal of the second transistor is electrically connected to a second terminal of the first transistor, a gate terminal of the second transistor is electrically connected to the second wire via the first switch, a second terminal of the second transistor is electrically connected to a load and is electrically connected to the third wire via the second switch;

a capacitor element electrically connected between the gate terminal of the second transistor and the second terminal of the second transistor; and

means for short circuiting between the first terminal of the first transistor and the second terminal of the first transistor.

2. The semiconductor device according to claim 1, wherein each of the first switch and the second switch includes a transistor.

3. The semiconductor device according to claim 1, wherein a potential of the first wire is higher than a potential of the second wire.

4. The semiconductor device according to claim 1, wherein the first transistor and the second transistor have a same conductivity.

5. The semiconductor device according to claim 1, wherein the means for short circuiting contains a switch electrically connected to the first terminal and the second terminal of the first transistor.

6. The semiconductor device according to claim 1, wherein the load includes a display element having a rectifying property.

7. The semiconductor device according to claim 1, wherein the load includes an EL element.

8. The semiconductor device according to claim 1, wherein the semiconductor device is a display device.

9. The semiconductor device according to claim 1, wherein the semiconductor device is one selected from the group consisting of a camera, a computer, an image reproducing device, a goggle-type display, a game machine, and a mobile phone.

10. A semiconductor device comprising:

a first wire;

a second wire;

a third wire;

a first switch;

a second switch;

a first transistor, wherein a first terminal of the first transistor is electrically connected to the first wire and a gate terminal of the first transistor is electrically connected to the second wire via the first switch;

a second transistor, wherein a first terminal of the second transistor is electrically connected to a second terminal of the first transistor, a gate terminal of the second transistor is electrically connected to the second wire via the first switch, a second terminal of the second transistor is electrically connected to a load and is electrically connected to the third wire via the second switch;

a capacitor element electrically connected between the gate terminal of the second transistor and the second terminal of the second transistor;

a current source electrically connected to the third wire; and

means for short circuiting between the first terminal of the first transistor and the second terminal of the first transistor.

11. The semiconductor device according to claim 10, wherein each of the first switch and the second switch includes a transistor.

12. The semiconductor device according to claim 10, wherein a potential of the first wire is higher than a potential of the second wire.

13. The semiconductor device according to claim 10, wherein the first transistor and the second transistor have a same conductivity.

14. The semiconductor device according to claim 10, wherein the means for short circuiting contains a switch electrically connected to the first terminal and the second terminal of the first transistor.

15. The semiconductor device according to claim 10, wherein the load includes a display element having a rectifying property.

16. The semiconductor device according to claim 10, wherein the load includes an EL element.

17. The semiconductor device according to claim 10, wherein the semiconductor device is a display device.

18. The semiconductor device according to claim 10, wherein the semiconductor device is one selected from the group consisting of a camera, a computer, an image reproducing device, a goggle-type display, a game machine, and a mobile phone.

19. A semiconductor device comprising:

a first wire;

a second wire;

a third wire;

a fourth wire;

a first switch;

a second switch;

a first transistor, wherein a first terminal of the first transistor is electrically connected to the first wire and a gate terminal of the first transistor is electrically connected to the second wire via the first switch;

a second transistor, wherein a first terminal of the second transistor is electrically connected to a second terminal of the first transistor, a gate terminal of the second transistor is electrically connected to the second wire via the first switch, a second terminal of the second transistor is electrically connected to a load and is electrically connected to the third wire via the second switch;

a capacitor element electrically connected between the gate terminal of the second transistor and the second terminal of the second transistor;

a first current source electrically connected to the third wire and a second current source electrically connected to the fourth wire; and

means for short circuiting between the first terminal of the first transistor and the second terminal of the first transistor.

20. The semiconductor device according to claim 19, wherein each of the first switch and the second switch includes a transistor.

21. The semiconductor device according to claim 19, wherein a potential of the first wire is higher than a potential of the second wire.

22. The semiconductor device according to claim 19, wherein the first transistor and the second transistor have a same conductivity.

23. The semiconductor device according to claim 19, wherein the means for short circuiting contains a switch electrically connected to the first terminal and the second terminal of the first transistor.

24. The semiconductor device according to claim 19, wherein the load includes a display element having a rectifying property.

25. The semiconductor device according to claim 19, wherein the load includes an EL element.

26. The semiconductor device according to claim 19, wherein the semiconductor device is a display device.

27. The semiconductor device according to claim 19, wherein the semiconductor device is one selected from the group consisting of a camera, a computer, an image reproducing device, a goggle-type display, a game machine, and a mobile phone.