Pixel driving circuit including drive transistor capable of generating drive current independent of threshold voltage thereof driving method thereby, and display panel

A driving method of a pixel driving circuit,

• the pixel driving circuit comprising:
• a first transistor having a first electrode electrically connected to a first voltage terminal and a second electrode electrically connected to an anode of a light-emitting device and electrically connected to a second voltage terminal via the light-emitting device;
• a second transistor having a source and a drain electrically connected respectively to a data line and the second electrode of the first transistor, and a gate connected to a scan signal, the data line being used for transmitting a composite signal, the composite signal having a first voltage as a reset signal in a first level state during a reset phase in which a potential of the anode of the light-emitting device is reset and a potential of the gate of the first transistor is reset, and the composite signal further having a second voltage in a second level state during a compensation phase, the first voltage being less than the second voltage;
• a third transistor having a source and a drain electrically connected respectively to a gate and the first electrode of the first transistor;
• a first capacitor having two terminals connected respectively to the gate of the first transistor and the anode of the light-emitting device;
• a second capacitor having two terminals connected respectively to the first voltage terminal and the light-emitting device, or respectively to the second voltage terminal and the light-emitting device;
• wherein the second voltage terminal is configured to provide a second voltage signal having a voltage greater than the first voltage;
• a parasitic capacitance is generated between the anode of the light-emitting device and a signal line for transmitting the second voltage signal;
• and
• a sum of a capacitance value of the parasitic capacitance and a capacitance value of the second capacitor is greater than a capacitance value of the first capacitor;
• the driving method comprising:
• in the reset phase, transmitting, by the second transistor, the reset signal to the anode of the light-emitting device based on the scan signal, to reset the potential of the anode potential of the light-emitting device so that the light-emitting device is non-conductive;
• and transmitting, by the third transistor, a first voltage signal transmitted by the first voltage terminal to the gate of the first transistor based on the scan signal, to reset the potential of the gate of the first transistor;
• in the compensation phase, transmitting, by the second transistor, the data signal to the second electrode of the first transistor based on the scan signal, and transmitting, by the third transistor, the data signal to the gate of the first transistor based on the scan signal;
• and
• in a light-emitting phase, based on the data signal, generating, by the first transistor, a driving current for driving the light-emitting device to emit light;
• wherein the pixel driving circuit further comprises:
• a fourth transistor, having a source and a drain which are electrically connected respectively to the light-emitting device and the second electrode of the first transistor;
• wherein a moment at which the composite signal jumps from the first level state to the second level state is same as a moment at which the fourth transistor transitions from an on state to an off state.

A display panel, comprising a plurality of pixel driving circuits and a plurality of light-emitting devices, wherein each of at least one of the plurality of pixel driving circuits comprises:

• a first transistor having a first electrode electrically connected to a first voltage terminal and a second electrode electrically connected to an anode of a light-emitting device and electrically connected to a second voltage terminal via the light-emitting device;
• a second transistor having a source and a drain electrically connected respectively to a data line and the second electrode of the first transistor, and a gate connected to a scan signal, the data line being used for transmitting a composite signal, the composite signal having a first voltage as a reset signal in a first level state during a reset phase in which a potential of the anode of the light-emitting device is reset and a potential of the gate of the first transistor is reset, and the composite signal further having a second voltage in a second level state during a compensation phase, the first voltage being less than the second voltage;
• a third transistor having a source and a drain electrically connected respectively to a gate and the first electrode of the first transistor;
• a first capacitor having two terminals connected respectively to the gate of the first transistor and the anode of the light-emitting device;
• and
• a second capacitor having two terminals connected respectively to the first voltage terminal and the light-emitting device, or respectively to the second voltage terminal and the light-emitting device;
• wherein the second voltage terminal is configured to provide a second voltage signal having a voltage greater than the first voltage;
• a parasitic capacitance is generated between the anode of the light-emitting device and a signal line for transmitting the second voltage signal;
• a sum of a capacitance value of the parasitic capacitance and a capacitance value of the second capacitor is greater than a capacitance value of the first capacitor;
• wherein the second transistor is configured to:
• in the reset phase, transmit the reset signal to the anode of the light-emitting device based on the scan signal, to reset the potential of the anode of the light-emitting device so that the light-emitting device is non-conductive;
• and in the compensation phase, transmit the data signal to the second electrode of the first transistor based on the scan signal;
• the third transistor is configured to:
• in the reset phase, transmit a first voltage signal transmitted by the first voltage terminal to the gate of the first transistor based on the scan signal, to reset the potential of the gate of the first transistor;
• and in a compensation phase, transmit the data signal to the gate of the first transistor based on the scan signal;
• and
• the first transistor is configured to:
• in a light-emitting phase, based on the data signal, generate a drive current for driving the light-emitting device to emit light;
• wherein the pixel driving circuit further comprises:
• a fourth transistor, having a source and a drain which are electrically connected respectively to the light-emitting device and the second electrode of the first transistor;
• wherein a moment at which the composite signal jumps from the first level state to the second level state is same as a moment at which the fourth transistor transitions from an on state to an off state.