Pixel circuit and driving method thereof, display substrate and display device
The pixel circuit includes: a light emitting module configured to emit light; a driving module configured to drive the light emitting module to emit light according to a driving voltage during a light emitting stage; a storage module configured to maintain the driving voltage and to provide the driving voltage to the driving module during the light emitting stage; a first transistor, a first electrode of the first transistor being connected to a position where the driving module receives the driving voltage, and a second electrode of the first transistor being not directly connected to a signal source; a second transistor, a first electrode of the second transistor being connected to the first electrode of the first transistor, wherein a structure to which a second electrode of the second transistor is connected is different from a structure to which the second electrode of the first transistor is connected.
1. A pixel circuit, comprising:
a light emitting module configured to emit light;
a driving module configured to drive the light emitting module to emit light according to a driving voltage during a light emitting stage;
a storage module configured to maintain the driving voltage and to provide the driving voltage to the driving module during the light emitting stage;
a first transistor, a first electrode of the first transistor being connected to the driving module, and a second electrode of the first transistor being not directly connected to a signal source;
a second transistor, a first electrode of the second transistor being connected to the first electrode of the first transistor, wherein a structure to which a second electrode of the second transistor is connected is different from a structure to which the second electrode of the first transistor is connected; and
a voltage stabilizing capacitor, a first electrode of the voltage stabilizing capacitor being connected to the second electrode of the first transistor, and a second electrode of the voltage stabilizing capacitor being connected to a constant voltage signal terminal;
the pixel circuit further comprises:
a third transistor, a first electrode of the third transistor being connected to the second electrode of the first transistor, and a gate of the third transistor being connected to a gate of the first transistor;
a fourth transistor, a first electrode of the fourth transistor being connected to the second electrode of the second transistor, and a gate of the fourth transistor being connected to a gate of the second transistor;
wherein the light emitting module comprises a light emitting device;
the driving module comprises a driving transistor configured to drive the light emitting device to emit light according to a voltage at a gate of the driving transistor; and
the storage module comprises a storage capacitor, which has a first electrode connected to the gate of the driving transistor and is configured to maintain the driving voltage at the first electrode thereof and provide the driving voltage to the driving module during the light emitting stage; and
the pixel circuit comprises a first reset module, a write module and a luminous control module;
the first reset module is configured to reset the voltage at the gate of the driving transistor according to signals at an initialization signal terminal and a first reset signal terminal; the first reset module comprises:
the first transistor;
the third transistor, the first electrode of the third transistor being connected to the second electrode of the first transistor, a second electrode of the third transistor being connected to the initialization signal terminal and the gate of the third transistor being connected to the gate of the first transistor and the first reset signal terminal;
the write module is configured to write the driving voltage to the first electrode of the storage capacitor according to signals at a gate signal terminal and a data signal terminal; the write module comprises:
the second transistor;
the fourth transistor, the first electrode of the fourth transistor being connected to the second electrode of the second transistor, a second electrode of the fourth transistor being connected to the second electrode of the driving transistor and the gate of the fourth transistor being connected to the gate of the second transistor and the gate signal terminal;
a fifth transistor, a first electrode of the fifth transistor being connected to the first electrode of the driving transistor, a second electrode of the fifth transistor being connected to the data signal terminal, and a gate of the fifth transistor being connected to the gate signal terminal;
the luminous control module comprises:
a sixth transistor, a first electrode of the sixth transistor being connected to a first power signal terminal, a second electrode of the sixth transistor being connected to the first electrode of the driving transistor, and a gate of the sixth transistor being connected to a control signal terminal:
wherein,
the driving transistor and the light emitting device are connected in series between the first power signal terminal and a second power signal terminal;
a second electrode of the storage capacitor is connected to the first power signal terminal;
a second electrode of the light emitting device is connected to the second power signal terminal; and
the write module further comprises a coupling capacitor, a first electrode of the coupling capacitor is connected to the first electrode of the fourth transistor, and a second electrode of the coupling capacitor is connected to the first power signal terminal.
2. The pixel circuit of claim 1 , wherein
the constant voltage signal terminal is any one of the initialization signal terminal, the first power signal terminal, and the second power signal terminal.
3. The pixel circuit of claim 1 , wherein
a capacitance value of the voltage stabilizing capacitor is greater than that of the coupling capacitor.
4. A display substrate, comprising:
a base plate; and
a plurality of sub-pixels on the base plate, at least a part of which comprise the pixel circuit of claim 1 .
5. The display substrate of claim 4 , wherein
the first electrode of the third transistor is connected to a second node;
the first electrode of the fourth transistor is connected to a third node;
and
a capacitance value of the voltage stabilizing capacitor is greater than that of the coupling capacitor.
6. The display substrate of claim 5 , wherein
the first electrode of the voltage stabilizing capacitor comprises: a connection portion connected between the first electrode of the third transistor and the second electrode of the first transistor; and an additional portion connected to the connection portion.
7. The display substrate of claim 6 , wherein
the first electrode of the voltage stabilizing capacitor and the second electrode of the first transistor are in a same layer and connected as a single piece;
the first electrode of the voltage stabilizing capacitor is in a same layer as an active region of the driving transistor, and is made of a conductorized semiconductor material;
the second electrode of the first transistor is in a same layer as the active region of the driving transistor, and is made of a conductorized semiconductor material; and
the second electrode of the voltage stabilizing capacitor and the constant voltage signal terminal are in a same layer and connected as a single piece.
8. The display substrate of claim 7 , wherein
the second electrode of the voltage stabilizing capacitor and the constant voltage signal terminal are in a same layer;
the constant voltage signal terminal comprises a first constant voltage signal terminal and a second constant voltage signal terminal in a same layer, and the first constant voltage signal terminal and the second constant voltage signal terminal are parallel to each other and separated from each other;
an orthographic projection of the first constant voltage signal terminal on the base plate is away from an orthographic projection of the first electrode of the third transistor and the second electrode of the first transistor on the base plate with respect to an orthographic projection of the second constant voltage signal terminal on the base plate; and
an orthographic projection of the additional portion on the base plate overlaps with the orthographic projection of the first constant voltage signal terminal on the base plate.
9. The display substrate of claim 8 , wherein
an orthographic projection of the connection portion on the base plate overlaps with the orthographic projection of the second constant voltage signal terminal on the base plate.
10. The display substrate of claim 8 , wherein
an orthographic projection of the connection portion on the base plate overlaps with the orthographic projection of the second constant voltage signal terminal on the base plate; and
the orthographic projection of the additional portion on the base plate overlaps with the orthographic projection of the first constant voltage signal terminal on the base plate and the orthographic projection of the second constant voltage signal terminal on the base plate.
11. The display substrate of claim 8 , wherein
an orthographic projection of the connection portion on the base plate overlaps with the orthographic projection of the first constant voltage signal terminal on the base plate; and
the orthographic projection of the additional portion on the base plate overlaps with the orthographic projection of the first constant voltage signal terminal on the base plate.
12. The display substrate of claim 8 , wherein
an area of orthographic projections of the connection portion and the additional portion on the base plate is more than a channel area of the first transistor by a factor of 3.
13. The display substrate of claim 8 , wherein
the light emitting module comprises a light emitting device;
the driving module comprises a driving transistor configured to drive the light emitting device to emit light according to a voltage at a gate of the driving transistor;
the storage module comprises a storage capacitor, which has a first electrode connected to the gate of the driving transistor and is configured to maintain the driving voltage at the first electrode thereof and provide the driving voltage to the driving module during the light emitting stage; and
a capacitance value of the voltage stabilizing capacitor is less than ¼ of that of the storage capacitor.
14. The display substrate of claim 13 , wherein
a capacitance value of the voltage stabilizing capacitor is not lower than 8 fF.
15. The display substrate of claim 8 , wherein
a capacitance value of the voltage stabilizing capacitor is greater than that of a coupling capacitor generated by a node between the second transistor and the fourth transistor.
16. The display substrate of claim 8 , wherein in a direction gradually away from the base plate, the display substrate sequentially comprises:
the active region of the driving transistor and the first electrode of the voltage stabilizing capacitor;
a gate insulating layer;
the gate of the driving transistor;
a first interlayer insulating layer; and
the second electrode of the voltage stabilizing capacitor and the constant voltage signal terminal.
17. The display substrate of claim 8 , wherein the constant voltage signal terminal is the initialization signal terminal, the first constant voltage signal terminal is the first initialization signal terminal, and the second constant voltage signal terminal is the second initialization signal terminal.
18. A display device, comprising:
a display substrate of claim 4 .