SEMICONDUCTOR DEVICE, AND DISPLAY DEVICE AND ELECTRONIC EQUIPMENT EACH HAVING THE SAME

• US 20070152921A1
• Filed: 10/10/2006
• Published: 07/05/2007
• Est. Priority Date: 10/18/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Osame, Mitsuaki
• Granted Patent: US 8,633,872 B2
• Time in Patent Office: Days
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• 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 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element

Abstract

Amplitude of a data line is made small, thereby reducing power consumption. Included are a first transistor to which a first scan signal is supplied through a first scan line; a second transistor to which a second scan signal is supplied through a second scan line; a third transistor which is turned on or off depending on a first signal supplied from a current supply line through the first transistor and a second signal supplied from a data line through the second transistor; a pixel electrode; and a light-emitting element which emits light by driving current flowing between the pixel electrode and a counter electrode. The first signal cuts electrical connection between the current supply line and the pixel electrode through the third transistor, and the second signal makes the current supply line and the pixel electrode electrically connected through the third transistor.

Claims

1. A semiconductor device comprising:

a first transistor to which a first scan signal is applied to a gate through a first scan line;

a second transistor to which a second scan signal is applied to a gate through a second scan line;

a third transistor which is turned on or off depending on a first signal and a second signal applied to a gate;

a pixel electrode; and

a light-emitting element which emits light by a driving current which flows between the pixel electrode and a counter electrode,

wherein the first signal supplied through the first transistor from a current supply line is a signal which cuts an electrical connection between the current supply line and the pixel electrode through the third transistor; and

wherein the second signal supplied through the second transistor from a data line is a signal which makes the current supply line and the pixel electrode electrically connected to each other through the third transistor.

4. The semiconductor device according to any one of claims 1 and 2, wherein a holding capacitor is provided between the gate of the third transistor and the current supply line.

5. The semiconductor device according to any one of claims 1 and 2, wherein the first transistor and the second transistor are N-channel transistors and the third transistor is a P-channel transistor.

12. The semiconductor device according to any one of claims 1, 2, 6 and 9, wherein amplitude of the first scan signal is larger than amplitude of the second scan signal.

13. A display device wherein the semiconductor device according to any one of claims 1, 2, 6 and 9 is provided for each pixel.

14. Electronic equipment wherein the display device according to any one of claims 1, 2, 6 and 9 is provided.

2. A semiconductor device comprising:

a first transistor to which a first scan signal is applied to a gate through a first scan line;

a second transistor to which a second scan signal is applied to a gate through a second scan line;

a third transistor which is turned on or off depending on a first signal and a second signal applied to a gate;

a pixel electrode; and

a light-emitting element which emits light by a driving current which flows between the pixel electrode and a counter electrode,

wherein the first signal supplied through the first transistor from a power supply line is a signal which cuts an electrical connection between a current supply line and the pixel electrode through the third transistor; and

wherein the second signal supplied through the second transistor from a data line is a signal which makes the current supply line and the pixel electrode electrically connected to each other through the third transistor.

3. The semiconductor device according to claim 2, wherein a potential of the power supply line and a potential of the current supply line are different.

6. A semiconductor device comprising:

a first transistor to which a first scan signal is applied to a gate through a first scan line;

a second transistor to which a second scan signal is applied to a gate through a second scan line;

a third transistor which is turned on or off depending on a potential of a current supply line;

a fourth transistor which is turned on or off depending on a first signal and a second signal applied to a gate;

a pixel electrode; and

a light-emitting element which emits light by a driving current which flows between the pixel electrode and a counter electrode,

wherein the first signal supplied through the first transistor and the third transistor from the first scan line is a signal which cuts an electrical connection between the current supply line and the pixel electrode through the fourth transistor; and

wherein the second signal supplied through the second transistor from a data line is a signal which makes the current supply line and the pixel electrode electrically connected to each other through the fourth transistor.

7. The semiconductor device according to claim 6, wherein a holding capacitor is provided between the gate of the fourth transistor and the current supply line.

8. The semiconductor device according to claim 6, wherein the first transistor, the second transistor, and the third transistor are N-channel transistors and the fourth transistor is a P-channel transistor.

9. A semiconductor device comprising:

a first transistor to which a first scan signal is applied to a gate through a first scan line;

a second transistor to which a second scan signal is applied to a gate through a second scan line;

a third transistor which is turned on or off depending on a potential of a current supply line;

a fourth transistor which is turned on or off depending on the first scan signal;

a fifth transistor which is turned on or off depending on a first signal and a second signal applied to a gate;

a pixel electrode; and

a light-emitting element which emits light by a driving current which flows between the pixel electrode and a counter electrode,

wherein the first signal supplied through the first transistor and the fourth transistor from the first scan line is a signal which cuts an electrical connection between the current supply line and the pixel electrode through the fifth transistor; and

wherein the second signal supplied through the second transistor from a data line is a signal which makes the current supply line and the pixel electrode electrically connected to each other through the fifth transistor.

10. The semiconductor device according to claim 9, wherein a holding capacitor is provided between the gate of the fifth transistor and the current supply line.

11. The semiconductor device according to claim 9, wherein the first transistor, the second transistor, the third transistor, and the fourth transistor are N-channel transistors and the fifth transistor is a P-channel transistor.

15. A driving method of a semiconductor device comprising:

a first transistor to which a first scan signal is applied to a gate through a first scan line;

a second transistor to which a second scan signal is applied to a gate through a second scan line;

a third transistor which is turned on or off depending on a potential applied to a gate;

a pixel electrode; and

a light-emitting element which emits light by a driving current which flows between the pixel electrode and a counter electrode,

the driving method comprising;

a first period during which the first transistor is turned on by the first scan signal, and a first signal for cutting an electrical connection between a current supply line and the pixel electrode through the third transistor is inputted to the gate of the third transistor through the first transistor from the current supply line;

a second period during which the first transistor is turned off by the first scan signal, and the second transistor is turned off by the second scan signal; and

a third period during which the second scan signal is inputted to the second transistor,

wherein in the third period, in the case where a potential of the data line is smaller than a potential of the second scan signal, a second signal for electrically connecting between the current supply line and the pixel electrode through the third transistor is inputted to the gate of the third transistor through the second transistor from the data line.

16. The driving method of the semiconductor device according to claim 15, wherein the first signal is inputted through the first transistor from a wire having a potential different from that of the current supply line.

17. The driving method of the semiconductor device according to claim 15, wherein the first transistor and the second transistor are N-channel transistors and the third transistor is a P-channel transistor.

22. The semiconductor device according to any one of claims 15, 18 and 20, wherein amplitude of the first scan signal is larger than amplitude of the second scan signal.

18. A driving method of a semiconductor device comprising:

a first transistor to which a first scan signal is applied to a gate through a first scan line;

a second transistor to which a second scan signal is applied to a gate through a second scan line;

a third transistor which is turned on or off depending on a potential of a current supply line;

a fourth transistor which is turned on or off depending on a signal applied to a gate;

a pixel electrode; and

a light-emitting element which emits light by a driving current which flows between the pixel electrode and a counter electrode,

the driving method comprising;

a first period during which the first transistor is turned on by the first scan signal, and a first signal for cutting an electrical connection between the current supply line and the pixel electrode through the fourth transistor is inputted to the gate of the fourth transistor through the first transistor and the third transistor from the first scan line;

a second period during which the first transistor is turned off by the first scan signal, and the second transistor is turned off by the second scan signal; and

a third period during which the second scan signal is inputted to the second transistor,

wherein in the third period, in the case where a potential of the data line is smaller than a potential of the second scan signal, a second signal for electrically connecting between the current supply line and the pixel electrode through the fourth transistor is inputted to the gate of the fourth transistor through the first transistor and the second transistor from the data line.

19. The driving method of the semiconductor device according to claim 18, wherein the first transistor, the second transistor, and the third transistor are N-channel transistors and the fourth transistor is a P-channel transistor.

20. A driving method of a semiconductor device comprising:

a first transistor to which a first scan signal is applied to a gate through a first scan line;

a second transistor to which a second scan signal is applied to a gate through a second scan line;

a third transistor which is turned on or off depending on a potential of a current supply line;

a fourth transistor which is turned on or off depending on the first scan signal;

a fifth transistor which is turned on or off depending on a signal applied to a gate;

a pixel electrode; and

a light-emitting element which emits light by a driving current which flows between the pixel electrode and a counter electrode,

the driving method comprising;

a first period during which the first transistor and the fourth transistor are turned on by the first scan signal, and a first signal for cutting an electrical connection between the current supply line and the pixel electrode through the fifth transistor is inputted to the gate of the fifth transistor through the first transistor and the fourth transistor from the first scan line;

a second period during which the first transistor is turned off by the first scan signal, and the second transistor is turned off by the second scan signal; and

a third period during which the second scan signal is inputted to the second transistor,

wherein in the third period, in the case where a potential of the data line is smaller than a potential of the second scan signal, a second signal for electrically connecting between the current supply line and the pixel electrode through the fourth transistor is inputted to the gate of the fourth transistor through the first transistor from the data line.

21. The driving method of the semiconductor device according to claim 20, wherein the first transistor, the second transistor, the third transistor, and the fourth transistor are N-channel transistors and the fifth transistor is a P-channel transistor.