Pixel circuit, display panel, display device and driving method

1. An organic light-emitting diode pixel circuit comprising:

an organic light-emitting diode (OLED);

a drive transistor, a first switch transistor, a second switch transistor, a third switch transistor, an eighth switch transistor; and

a first capacitor, a second capacitor, a fourth capacitor;

wherein the drive transistor has a source for receiving a first drive signal, a drain connected with an anode of the OLED, and a gate connected respectively with a first terminal of the third switch transistor, one end of the first capacitor and one end of the second capacitor;

wherein the OLED has a cathode for receiving a second drive signal;

wherein the first capacitor has another end connected with the source of the drive transistor;

wherein the first switch transistor has a first terminal connected with the source of the drive transistor, a gate for receiving a first clock signal, a second terminal connected respectively with another end of the second capacitor and a first terminal of the second switch transistor;

wherein the second switch transistor has a gate for receiving a second clock signal, and a second terminal connected respectively with a second terminal of the eighth switch transistor and one end of the fourth capacitor;

wherein the third switch transistor has a gate for receiving the first clock signal, and a second terminal connected with the anode of the OLED;

wherein the eighth switch transistor has a first terminal for receiving a data signal, in a current frame of image signal, to be displayed by a pixel, and a gate for receiving a gate line scan signal configured to enable a gate line connected with the pixel;

wherein the fourth capacitor has another end connected with the source of the drive transistor.

2. The circuit according to claim 1 , wherein:

in a period of time when a voltage of the first drive signal is not higher than a voltage of the second drive signal, the period of time comprises a first period and a second period, wherein the first period precedes the second period; and both the first drive signal and the second drive signal are at high levels in both the first period and the second period;

wherein both the first switch transistor and the third switch transistor are configured to be turned on in the first period and to be turned off in the second period by the first clock signal,

wherein the second switch transistor is configured to be turned off in the first period and to be turned on in the second period by the second clock signal, and

wherein both the first capacitor and the second capacitor are configured, in the first period, to store the first drive signal and a threshold signal dependent upon a threshold voltage, wherein the voltage of the threshold signal dependent upon the threshold voltage is the sum of the voltage of the first drive signal and the threshold voltage of the drive transistor; and

wherein in the second period, both the first capacitor and the second capacitor are configured to be charge redistributed by the signal of the second terminal of the second switch transistor, the stored first drive signal and the stored threshold signal, so that the

voltage of the first terminal of the second switch transistor is equal to the voltage of the second terminal of the second switch transistor.

3. The circuit according to claim 2 ,

wherein in the period of time when the voltage of the first drive signal is not higher than the voltage of the second drive signal, the period of time further comprises a third period preceding the first period; wherein both the first drive signal and the second drive signal are at a low level in the third period; and

wherein the first switch transistor and the third switch transistor are configured to be turned on in the third period by the first clock signal; and

wherein the second switch transistor is configured to be turned off in the third period by the second clock signal.

4. The circuit according to claim 1 ,

wherein the eighth switch transistor is configured to be turned on when the voltage of the first drive signal is higher than the voltage of the second drive signal, and wherein the gate line connected with the pixel is enabled to be turned off when the gate line connected with the pixel is disabled; and

wherein the fourth capacitor is configured to store a signal received when the eighth switch transistor is turned on, and is charged and discharged by the signal stored in the fourth capacitor when the voltage of the first drive signal is not higher than the voltage of the second drive signal.

5. A display device, comprising the organic light-emitting diode pixel circuit according to claim 1 .

6. An organic light-emitting diode pixel circuit comprising:

an organic light-emitting diode (OLED);

a drive transistor, a fourth switch transistor, a fifth switch transistor, a sixth switch transistor, a seventh switch transistor, and an eighth switch transistor; and

a third capacitor, and a fourth capacitor;

wherein the drive transistor has a source for receiving a first drive signal, a drain connected with an anode of the OLED, and a gate connected respectively with a first terminal of the fourth switch transistor and one end of the third capacitor;

wherein the OLED has a cathode for receiving a second drive signal;

wherein the fourth switch transistor has a gate for receiving a third clock signal, and a second terminal connected with the anode of the OLED;

wherein the third capacitor has another end connected respectively with a first terminal of the fifth switch transistor, a first terminal of the sixth switch transistor, and a first terminal of the seventh switch transistor;

wherein the fifth switch transistor has a gate for receiving a fourth clock signal, and a second terminal connected with the source of the drive transistor;

wherein the sixth switch transistor has a gate for receiving a fifth clock signal, and a second terminal for receiving a reference signal;

wherein the seventh switch transistor has a gate for receiving a sixth clock signal, and a second terminal connected respectively with a second terminal of the eighth switch transistor and one end of the fourth capacitor;

wherein the eighth switch transistor has a first terminal for receiving a data signal, in a current frame of image signal, to be displayed by a pixel, and a gate for receiving a gate line scan signal configured to enable a gate line connected with the pixel; and

wherein the fourth capacitor having another end connected with the source of the drive transistor.

7. The circuit according to claim 6 ,

wherein a period of time when a voltage of the first drive signal is not higher than a voltage of the second drive signal, the period of time comprises a first period, a second period, and a fourth period, the first period preceding the second period, the fourth period following the second period; and

wherein both the first drive signal and the second drive signal are at a high level in the first period, the second period and the fourth period;

wherein the fourth switch transistor are configured to be turned on in both the first period and the second period and to be turned off in the fourth period;

wherein the fifth switch transistor are configured to be turned off in both the first period and the second period and to be turned on in the fourth period;

wherein the sixth switch transistor are configured to be turned on in the first period and to be turned off in both the second period and the fourth period;

wherein the seventh switch transistor are configured to be turned off in both the first period and the fourth period and to be turned on in the second period; and

wherein the third capacitor are configured, in the first period, to store the reference signal and a signal dependent upon the threshold voltage, wherein the voltage of the threshold signal dependent upon the threshold voltage is the sum of the voltage of the first drive signal and the threshold voltage of the drive transistor;

wherein in the second period, the third capacitor is configured to be charge redistributed by the signal of the second terminal of the seventh switch transistor, the stored reference signal and the stored threshold signal dependent upon the threshold voltage, so that the voltage of the first terminal of the seventh switch transistor is equal to the voltage of the second terminal of the seventh switch transistor; and in the fourth period, to couple a change in voltage of the first terminal of the fifth switch transistor to the gate of the drive transistor.

8. The circuit according to claim 7 ,

wherein the period of time when the voltage of the first drive signal is not higher than the voltage of the second drive signal further comprises a third period preceding the first period; and wherein both the first drive signal and the second drive signal are at a low level in the third period; and

wherein the fourth switch transistor is configured to be turned on in the third period to set the gate of the drive transistor to a low level;

wherein the fifth switch transistor is configured to be turned off in the third period;

wherein the sixth switch transistor is configured to be turned on in the third period to set the one end of the third capacitor disconnected from the gate of the drive transistor to the voltage of the reference signal; and

wherein the seventh switch transistor is configured to be turned off in the third period.

9. The circuit according to claim 6 , wherein the eighth switch transistor is configured to be turned on when the voltage of the first drive signal is higher than the voltage of the second drive signal, and the gate line connected with the pixel is enabled and turned off when the gate line connected with the pixel is disabled; and

wherein the fourth capacitor is configured to store a signal received when the eighth switch transistor is turned on, and is charged and discharged by the signal stored in the fourth capacitor when the voltage of the first drive signal is not higher than the voltage of the second drive signal.