The present application claims priority to Chinese Patent Application No. 201810455140.6, filed on May 14, 2018, the disclosure of which is incorporated herein by reference in its entirety as part of the present application.

TECHNICAL FIELD

Embodiments of the present disclosure relate to a pixel circuit, a display panel, and a driving method.

BACKGROUND

With the development of display technology, a full screen devices has a large screen-to-body ratio and an ultra-narrow bezel, which can greatly improve the visual effect of the viewer, compared with a device having an ordinary display screen, and thus has received extensive attention. Therefore, in order to meet the requirements of a full screen display, in-screen or under-screen fingerprint recognition technology has become a research focus in this field.

SUMMARY

At least one embodiment of the present disclosure provides a pixel circuit comprising a data writing circuit, an ultrasonic acquiring and converting circuit, a storage circuit, a driving circuit, an output control circuit, and a light emitting device; the ultrasonic acquiring and converting circuit is configured to convert a received ultrasonic signal into a converted electrical signal, and to provide the converted electrical signal to the data writing circuit; the data writing circuit is configured to provide a data signal or the converted electrical signal obtained by the ultrasonic acquiring and converting circuit to a first node under a control of a scanning signal; the driving circuit is configured to provide a driving signal, which is used for driving the light emitting device to emit light, to a fourth node under a control of a level of a second node, or to provide a recognition signal obtained according to the converted electrical signal to the fourth node under the control of the level of the second node; the storage circuit is configured to maintain a voltage difference between the first node and the second node stable; the output control circuit is configured to provide a level of the fourth node to a third node under a control of an output control signal; the third node is configured to output the recognition signal; and a first electrode of the light emitting device is configured to be connected to the third node, and a second electrode of the light emitting device is configured to receive a first voltage signal.

For example, in the pixel circuit provided by an embodiment of the present disclosure, the ultrasonic acquiring and converting circuit is connected to the data writing circuit, the data writing circuit is connected to the first node, the storage circuit is connected to the first node and the second node, the driving circuit is connected to the second node and the fourth node, and the output control circuit is connected to the fourth node and the third node.

For example, in the pixel circuit provided by an embodiment of the present disclosure, the first voltage signal is configured to cause the light emitting device not to emit light in a case where the ultrasonic acquiring and converting circuit provides the converted electrical signal to the data writing circuit.

For example, the pixel circuit provided by an embodiment of the present disclosure further comprising a threshold acquisition circuit, the threshold acquisition circuit is connected to the second node and the fourth node, and is configured to provide the level of the fourth node to the second node under a control of the scanning signal.

For example, the pixel circuit provided by an embodiment of the present disclosure further comprising a first node reset circuit, the first node reset circuit is connected to the first node, and is configured to provide a second voltage signal to the first node under a control of the output control signal or a reset signal.

For example, the pixel circuit provided by an embodiment of the present disclosure further comprising a second node reset circuit, the second node reset circuit is connected to the second node, and is configured to provide a third voltage signal to the second node under a control of the reset signal.

For example, the pixel circuit provided by an embodiment of the present disclosure further comprising a third node reset circuit, the third node reset circuit is connected to the third node, and is configured to provide the third voltage signal to the third node under a control of the scanning signal.

For example, in the pixel circuit provided by an embodiment of the present disclosure, the first node reset circuit comprises a first transistor and a second transistor; a gate electrode of the first transistor is configured to receive the output control signal, a first electrode of the first transistor is configured to receive the second voltage signal, and a second electrode of the first transistor is connected to the first node; a gate electrode of the second transistor is configured to receive the reset signal, a first electrode of the second transistor is configured to receive the second voltage signal, and a second electrode of the second transistor is connected the first node.

For example, in the pixel circuit provided by an embodiment of the present disclosure, the second node reset circuit comprises a seventh transistor; a gate electrode of the seventh transistor is configured to receive the reset signal, a first electrode of the seventh transistor is configured to receive the third voltage signal, and a second electrode of the seventh transistor is connected to the second node.

For example, in the pixel circuit provided by an embodiment of the present disclosure, the third node reset circuit comprises an eighth transistor; a gate electrode of the eighth transistor is configured to receive the scanning signal, a first electrode of the eighth transistor is configured to receive the third voltage signal, and a second electrode of the eighth transistor is connected to the third node.

For example, in the pixel circuit provided by an embodiment of the present disclosure, the data writing circuit comprises a fourth transistor; a gate electrode of the fourth transistor is configured to receive the scanning signal, a first electrode of the fourth transistor is connected to the ultrasonic acquiring and converting circuit and configured to receive the data signal, and a second electrode of the fourth transistor is connected to the first node.

For example, in the pixel circuit provided by an embodiment of the present disclosure, the storage circuit comprises a storage capacitor, a first electrode of the storage capacitor is connected to the first node, and a second electrode of the storage capacitor is connected to the second node.

For example, in the pixel circuit provided by an embodiment of the present disclosure, the driving circuit comprises a third transistor; a gate electrode of the third transistor is connected to the second node, a first electrode of the third transistor is configured to receive a fourth voltage signal, and a second electrode of the third transistor is connected to the fourth node.

For example, in the pixel circuit provided by an embodiment of the present disclosure, the threshold acquisition circuit comprises a fifth transistor; a gate electrode of the fifth transistor is configured to receive the scanning signal, a first electrode of the fifth transistor is connected to the fourth node, and a second electrode of the fifth transistor is connected to the second node.

For example, in the pixel circuit provided by an embodiment of the present disclosure, the output control circuit comprises a sixth transistor; a gate electrode of the sixth transistor is configured to receive the output control signal, a first electrode of the sixth transistor is connected to the fourth node, and a second electrode of the sixth transistor is connected to the third node.

For example, the pixel circuit provided by an embodiment of the present disclosure further comprising a light emitting control circuit, the light emitting control circuit is configured to provide a level of the third node to the light emitting device under a control of a light emitting control signal.

For example, in the pixel circuit provided by an embodiment of the present disclosure, the light emitting control circuit comprises a ninth transistor; a gate electrode of the ninth transistor is configured to receive the light emitting control signal, a first electrode of the ninth transistor is connected to the third node, a second electrode of the ninth transistor is connected to the first electrode of the light emitting device.

At least one embodiment of the present disclosure further provides a display panel comprising a display area, the display area comprises a fingerprint recognition area in which the pixel circuit according to an embodiment of the present disclosure is disposed.

For example, the display panel provided by an embodiment of the present disclosure further comprising a scanning signal line, a data signal line, and a reading signal line, the scanning signal line is configured to provide the scanning signal, the data signal line is configured to provide the data signal, and the reading signal line is configured to read the recognition signal.

At least one embodiment of the present disclosure further provides a method for driving the pixel circuit, and the method comprises: during an acquisition and conversion phase, causing the data writing circuit to provide the converted electrical signal obtained by the ultrasonic acquiring and converting circuit to the first node; and during an output phase, causing the driving circuit and the output control circuit to be turned on, providing, by the driving circuit, the recognition signal obtained according to the converted electrical signal to the fourth node, and providing, by the output control circuit, the level of the fourth node to the third node.

At least one embodiment of the present disclosure further provides a method for driving the pixel circuit, and the method comprises: during a reset phase, causing the first node reset circuit to provide the second voltage signal to the first node under the control of the reset signal, and causing the second node reset circuit to provide the third voltage signal to the second node under the control of the reset signal; during an acquisition and conversion phase, causing the data writing circuit to provide the converted electrical signal obtained by the ultrasonic acquiring and converting circuit to the first node, causing the threshold acquisition circuit to write a threshold voltage of the driving circuit to the second node, and causing the third node reset circuit to provide the third voltage signal to the third node under the control of the scanning signal; during an output phase, causing the first node reset circuit to provide the second voltage signal to the first node under the control of the output control signal, causing the driving circuit and the output control circuit to be turned on, providing, by the driving circuit, the recognition signal obtained according to the converted electrical signal to the fourth node, and providing, by the output control circuit, the level of the fourth node to the third node.

At least one embodiment of the present disclosure further provides a method for driving the display panel, and the method comprises: causing the pixel circuit in the fingerprint recognition area to perform a display operation and a fingerprint recognition operation respectively during different time periods.

