Semiconductor Device and Driving Method Thereof, and Electronic Device

• US 20100220092A1
• Filed: 02/25/2010
• Published: 09/02/2010
• Est. Priority Date: 02/27/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kimura, Hajime
• Granted Patent: US 8,487,923 B2
• Time in Patent Office: Days
• US Class Current: 345/213
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0852 being a dynamic memory with more than one capacitor
• CPC Class Codes: G09G 2300/0876 Supplementary capacities in pixels having special driving circuits and electrodes instead of being connected to common electrode or ground; Use of additional capacitively coupled compensation electrodes
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

A driving method of a semiconductor device for compensating variation in threshold voltage and mobility of a transistor is provided. A driving method of a semiconductor device including a transistor and a capacitor electrically connected to a gate of the transistor includes a first period where voltage corresponding to threshold voltage of the transistor is held in the capacitor, a second period where a total voltage of video signal voltage and threshold voltage is held in the capacitor holding the threshold voltage, and a third period where charge held in the capacitor in accordance with the total voltage of the video signal voltage and the threshold voltage in the second period is discharged through the transistor.

Claims

1. A driving method of a semiconductor device including a transistor and a capacitor, wherein one electrode of the capacitor is electrically connected to a gate of the transistor, comprising the steps of:

charging the capacitor;

discharging the capacitor so that a voltage between the one electrode and the other electrode of the capacitor is a first voltage corresponding to a threshold voltage of the transistor;

supplying a video signal to the other electrode of the capacitor while holding the first voltage in the capacitor; and

discharging the capacitor so that a discharge current passes through the transistor after supplying the video signal to the other electrode of the capacitor.

2. A driving method of a semiconductor device including a transistor, a first capacitor and a second capacitor, wherein one electrode of the first capacitor is electrically connected to a gate of the transistor and wherein one electrode of the second capacitor is electrically connected to the other electrode of the first capacitor, comprising the steps of:

charging the first capacitor;

discharging the first capacitor so that a voltage between the one electrode and the other electrode of the first capacitor is a first voltage corresponding to a threshold voltage of the transistor;

supplying a video signal to the one electrode of the second capacitor so that a voltage between the one electrode and the other electrode of the second capacitor is a second voltage corresponding to the video signal while holding the first voltage in the first capacitor; and

discharging the first capacitor so that a discharge current passes through the transistor after supplying the video signal to the one electrode of the second capacitor.

3. A driving method of a semiconductor device including a transistor, a capacitor and a display element, wherein one electrode of the capacitor is electrically connected to a gate of the transistor, comprising the steps of:

charging the capacitor;

discharging the capacitor so that a voltage between the one electrode and the other electrode of the capacitor is a first voltage corresponding to a threshold voltage of the transistor;

supplying a video signal to the other electrode of the capacitor while holding the first voltage in the capacitor;

discharging the capacitor so that a first current passes through the transistor and so that a voltage between the one electrode and the other electrode of the capacitor is a second voltage after supplying the video signal to the other electrode of the capacitor; and

supplying a second current to the display element through the transistor while holding the second voltage in the capacitor.

4. A driving method of a semiconductor device including a transistor, a first capacitor, a second capacitor and a display element, wherein one electrode of the first capacitor is electrically connected to a gate of the transistor and wherein one electrode of the second capacitor is electrically connected to the other electrode of the first capacitor, comprising the steps of:

charging the first capacitor;

discharging the first capacitor so that a voltage between the one electrode and the other electrode of the first capacitor is a first voltage corresponding to a threshold voltage of the transistor;

supplying a video signal to the one electrode of the second capacitor while holding the first voltage in the first capacitor;

discharging the first capacitor so that a first current passes through the transistor and so that a voltage between the one electrode and the other electrode of the first capacitor is a second voltage after supplying the video signal to the one electrode of the second capacitor; and

supplying a second current to the display element through the transistor while holding the second voltage in the first capacitor.

5. A semiconductor device comprising:

a first transistor;

a second transistor;

a third transistor;

a fourth transistor;

a fifth transistor,

a first capacitor; and

a second capacitor,

wherein a gate of the first transistor is electrically connected to one electrode of the first capacitor,

wherein one of a source and a drain of the second transistor is electrically connected to the gate of the first transistor,

wherein the other of the source and the drain of the second transistor is electrically connected to one of a source and a drain of the first transistor,

wherein one of a source and a drain of the third transistor is electrically connected to the other electrode of the first capacitor,

wherein the other of the source and the drain of the third transistor is electrically connected to the other of the source and the drain of the first transistor;

wherein the other of the source and the drain of the first transistor is electrically connected to a second wiring,

wherein one electrode of the second capacitor is electrically connected to the other electrode of the first capacitor,

wherein one of a source and a drain of the fourth transistor is electrically connected to the one of the second capacitor,

wherein the other of the source and the drain of the fourth transistor is electrically connected to a first wiring,

wherein one of a source and a drain of the fifth transistor is electrically connected to the one of the source and the drain of the first transistor, and

wherein the other of the source and the drain of the fifth transistor is electrically connected to a pixel electrode.

6. The semiconductor device according to claim 5,

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

7. The semiconductor device according to claim 5,

wherein the other electrode of the second capacitor is electrically connected to a third wiring.

8. An electronic device comprising:

a semiconductor device according to claim 5; and

an operation switch.

9. A semiconductor device comprising:

a transistor;

a first capacitor wherein one electrode of the first capacitor is electrically connected to a gate of the transistor;

a second capacitor wherein one electrode of the second capacitor is electrically connected to the other electrode of the first capacitor;

a first switch configured to connect through an electric contact between the gate of the transistor and one of a source and a drain of the transistor;

a second switch configured to connect through an electric contact between the other of the source and the drain of the transistor and the other electrode of the first capacitor;

a third switch configured to connect through an electric contact between a first wiring and the one electrode of the second capacitor; and

a fourth switch configured to connect through an electric contact between a pixel electrode and the one of the source and the drain of the transistor.

10. An electronic device comprising:

a semiconductor device according to claim 9; and

an operation switch.