Pixel circuit, display panel, display unit, and electronic system

1. A pixel circuit, comprising:

a writing circuit sampling a voltage of a signal line; and

a driving circuit generating from the signal line a current that depends on an output of the writing circuit, and delivering the current to a light-emitting device of a current-drive type,

wherein a peripheral circuit that drives the pixel circuit:

causes a driving transistor of the driving circuit to sample the voltage of the signal line while applying to the signal line a signal voltage that corresponds to an image signal;

modifies a gate-source voltage of the driving transistor using a voltage obtained through the sampling by the driving transistor; and

applies to the signal line a voltage that is independent of the image signal, to turn on the driving transistor utilizing a capacitive coupling derived from a first capacitor device connected across a gate and one of a source and a drain of the driving transistor and a second capacitor device connected across a source and a drain of a writing transistor of the writing circuit and connected across the gate and the other of the source and drain of the driving transistor, and thereby to put the light-emitting device in a light-emitting state.

2. The pixel circuit according to claim 1 , wherein one of the source and a drain of the driving transistor is connected with the signal line, one of the source and the drain of the driving transistor that is unconnected with the signal line is connected with the light-emitting device, and the gate of the driving transistor is connected with an output terminal of the writing circuit.

3. The pixel circuit according to claim 2 , wherein one of the source and the drain of the writing transistor is connected with the signal line, one of the source and the drain of the writing transistor that is unconnected with the signal line is connected with the gate of the driving transistor, and the gate of the writing transistor is connected with the signal line.

4. The pixel circuit according to claim 1 , wherein the light-emitting device is an organic electroluminescence device.

5. A display panel, comprising:

a light-emitting device of a current-drive type provided for each pixel; and

a pixel circuit provided for each of the pixels and driving the corresponding light-emitting device, each of the pixel circuits including:

a writing circuit sampling a voltage of a signal line, and

a driving circuit generating from the signal line a current that depends on an output of the writing circuit, and delivering the current to the light-emitting device,

wherein a peripheral circuit that drives the pixel circuit:

causes a driving transistor of the driving circuit to sample the voltage of the signal line while applying to the signal line a signal voltage that corresponds to an image signal;

modifies a gate-source voltage of the driving transistor using a voltage obtained through the sampling by the driving transistor; and

applies to the signal line a voltage that is independent of the image signal, to turn on the driving transistor utilizing a capacitive coupling derived from a first capacitor device connected across a gate and one of a source and a drain of the driving transistor and a second capacitor device connected across a source and a drain of a writing transistor of the writing circuit and connected across the gate and the other of the source and drain of the driving transistor, and thereby to put the light-emitting device in a light-emitting state.

6. A display unit, comprising:

a display panel including a light-emitting device of a current-drive type and a pixel circuit, the light-emitting device being provided for each pixel, and the pixel circuit being provided for each of the pixels and driving the corresponding light-emitting device; and a peripheral circuit driving the pixel circuits, each of the pixel circuits including:

a writing circuit sampling a voltage of a signal line, and

a driving circuit generating from the signal line a current that depends on an output of the writing circuit, and delivering the current to the light-emitting device,

wherein the peripheral circuit:

causes a driving transistor of the driving circuit to sample the voltage of the signal line while applying to the signal line a signal voltage that corresponds to an image signal;

modifies a gate-source voltage of the driving transistor using a voltage obtained through the sampling by the driving transistor; and

applies to the signal line a voltage that is independent of the image signal, to turn on the driving transistor utilizing a capacitive coupling derived from a first capacitor device connected across a gate and one of a source and a drain of the driving transistor and a second capacitor device connected across a source and a drain of a writing transistor of the writing circuit and connected across the gate and the other of the source and drain of the driving transistor, and thereby to put the light-emitting device in a light-emitting state.

7. The display unit according to claim 6 , wherein one of the source and a drain of the driving transistor is connected with the signal line, one of the source and the drain of the driving transistor that is unconnected with the signal line is connected with the light-emitting device, and the gate of the driving transistor is connected with an output terminal of the writing circuit.

8. The display unit according to claim 7 , wherein one of the source and the drain of the writing transistor is connected with the signal line, one of the source and the drain of the writing transistor that is unconnected with the signal line is connected with the gate of the driving transistor, and the gate of the writing transistor is connected with the signal line.

9. An electronic system, comprising

a display unit including a display panel and a peripheral circuit, the display panel including a light-emitting device of a current-drive type and a pixel circuit, the light-emitting device being provided for each pixel, the pixel circuit being provided for each of the pixels and driving the corresponding light-emitting device, and the peripheral circuit driving the pixel circuits,

each of the pixel circuits including:

a writing circuit sampling a voltage of a signal line, and

a driving circuit generating from the signal line a current that depends on an output of the writing circuit, and delivering the current to the light-emitting device,

wherein the peripheral circuit:

causes a driving transistor of the driving circuit to sample the voltage of the signal line while applying to the signal line a signal voltage that corresponds to an image signal;

modifies a gate-source voltage of the driving transistor using a voltage obtained through the sampling by the driving transistor; and

applies to the signal line a voltage that is independent of the image signal, to turn on the driving transistor utilizing a capacitive coupling derived from a first capacitor device connected across a gate and one of a source and a drain of the driving transistor and a second capacitor device connected across a source and a drain of a writing transistor of the writing circuit and connected across the gate and the other of the source and drain of the driving transistor, and thereby to put the light-emitting device in a light-emitting state.

10. The display panel according to claim 5 , wherein one of the source and a drain of the driving transistor is connected with the signal line, one of the source and the drain of the driving transistor that is unconnected with the signal line is connected with the light-emitting device, and the gate of the driving transistor is connected with an output terminal of the writing circuit.

11. The display panel according to claim 10 , wherein one of the source and the drain of the writing transistor is connected with the signal line, one of the source and the drain of the writing transistor that is unconnected with the signal line is connected with the gate of the driving transistor, and the gate of the writing transistor is connected with the signal line.

12. The display panel according to claim 5 , wherein the light-emitting device is an organic electroluminescence device.

13. The electronic system according to claim 9 , wherein one of the source and a drain of the driving transistor is connected with the signal line, one of the source and the drain of the driving transistor that is unconnected with the signal line is connected with the light-emitting device, and the gate of the driving transistor is connected with an output terminal of the writing circuit.

14. The electronic system according to claim 13 , wherein one of the source and the drain of the writing transistor is connected with the signal line, one of the source and the drain of the writing transistor that is unconnected with the signal line is connected with the gate of the driving transistor, and the gate of the writing transistor is connected with the signal line.

15. The electronic system according to claim 9 , wherein the light-emitting device is an organic electroluminescence device.

16. The pixel circuit according to claim 1 , wherein the one of the source and a drain of the driving transistor that is connected to the first capacitor device is connected to the light emitting device.

17. The pixel circuit according to claim 16 , wherein the other of the source and drain of the driving transistor that is connected to the second capacitor device is connected to the signal line.