The present application is 371 of PCT Application No. PCT/CN2020/092041, filed on May 25, 2020, which claims priority to Chinese Patent Application No. 201910447406.7, filed on May 27, 2019 and titled “TEXTURE DETECTION CIRCUIT, CHARGING CIRCUIT, DRIVING METHOD, AND TOUCH DISPLAY PANEL”, which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to a texture detection circuit, a charging circuit, driving methods and a touch display panel.

BACKGROUND

A touch display panel includes a plurality of pixel units arranged in an array, the pixel unit is provided with a pixel detection sub-circuit, the pixel detection sub-circuit is configured to convert a detected optical signal into an electrical signal and output the electrical signal to a processing module through a signal readout line, and the processing module is configured to determine whether there is a touch operation in a corresponding pixel region based on the electrical signal output by the signal readout line.

The pixel unit is provided with a light source for fingerprint detection, and the pixel detection sub-circuit in each pixel unit includes a photosensitive diode. When a finger presses on a surface of a display panel corresponding to a certain pixel unit, the light source in the pixel unit begins to emit light. Further, due to difference between valleys and ridges of the finger, the light emitted by the light source irradiates on the valleys and the ridges to produce different reflections, so that there is a difference in light intensity reflected onto the photosensitive diode in the pixel unit. The photosensitive diode may generate electric currents with different magnitudes based on the different light intensities and transmit the electric currents with different magnitudes to the processing module through the signal readout line, and then, the processing module may detect the ridges and the valleys by detecting the electric currents with different magnitudes, thereby realizing detection and recognition of the fingerprint.

SUMMARY

The present disclosure provides a texture detection circuit, a charging circuit, a method for driving the texture detection circuit, a method for driving the charging circuit, and a touch display panel. The technical solutions are as below.

In one aspect, a texture detection circuit is provided. The texture detection circuit includes a first photosensitive element and a switching sub-circuit.

A first electrode of the first photosensitive element is connected with a signal readout line, and a second electrode of the first photosensitive element is connected with the switching sub-circuit.

The switching sub-circuit is also connected with a reverse power end and a charging sub-circuit, and the switching sub-circuit is configured to switch a connection state of the second electrode of the first photosensitive element between a first connection state and a second connection state. The first connection state is a state in which the second electrode of the first photosensitive element is connected with the reverse power end, and the second connection state is a state in which the second electrode of the first photosensitive element is connected with the charging sub-circuit.

Optionally, the switching sub-circuit includes a second transistor and a third transistor.

A gate of the second transistor is connected with a second control signal terminal, a first electrode of the second transistor is connected with the reverse power end, and a second electrode of the second transistor is connected with the second electrode of the first photosensitive element.

A gate of the third transistor is connected with a third control signal terminal, a first electrode of the third transistor is connected with the second electrode of the first photosensitive element, and a second electrode of the third transistor is connected with the charging sub-circuit.

Optionally, the texture detection circuit further includes a first on-off sub-circuit.

The first on-off sub-circuit is connected in series between the first electrode of the first photosensitive element and the signal readout line.

Optionally, the first on-off sub-circuit includes a first transistor.

A gate of the first transistor is connected with a first control signal terminal, a first electrode of the first transistor is connected with the first electrode of the first photosensitive element, and a second electrode of the first transistor is connected with the signal readout line.

In another aspect, a charging circuit is provided. The charging circuit includes a charging sub-circuit and any texture detection circuit described in the first aspect. The second electrode of the first photosensitive element in the texture detection circuit is connected with the charging sub-circuit.

The texture detection circuit is configured to provide an electrical signal to the charging sub-circuit, and the electrical signal is acquired after the first photosensitive element converts a detected optical signal.

The charging sub-circuit is configured to store the electrical signal in a form of electric energy.

Optionally, the charging circuit includes a plurality of texture detection circuits connected in series.

In the plurality of texture detection circuits connected in series, the switching sub-circuit in a first texture detection circuit is connected with the charging sub-circuit, and other switching sub-circuits are connected with the charging sub-circuit through the texture detection circuits connected in series between the other switching sub-circuits and the charging sub-circuit.

The first texture detection circuit is any texture detection circuit located at both ends of the plurality of texture detection circuits connected in series, other switching sub-circuits are switching sub-circuits in other texture detection circuits, and the other texture detection circuits are texture detection circuits in the plurality of texture detection circuits connected in series other than the first texture detection circuit.

Optionally, the charging circuit further includes a second on-off sub-circuit and a first capacitor.

The second on-off sub-circuit is connected in series between the first electrode of the first photosensitive element and the charging sub-circuit.

One terminal of the first capacitor is connected in series between the first electrode of the first photosensitive element and the second on-off sub-circuit, the other terminal of the first capacitor is connected with a first power end. The first capacitor is configured to: get charged by the electrical signal from the first electrode of the first photosensitive element when the second on-off sub-circuit is in an off state, and discharge to the charging sub-circuit when the second on-off sub-circuit is in an on state.

Optionally, the second on-off sub-circuit includes a fourth transistor.

A gate of the fourth transistor is connected with a fourth control signal terminal, a first electrode of the fourth transistor is connected with the first electrode of the first photosensitive element, and a second electrode of the fourth transistor is connected with the charging sub-circuit.

Optionally, the charging circuit further includes a third on-off sub-circuit.

The third on-off sub-circuit is connected in series between the first electrode of the first photosensitive element and one terminal of the first capacitor.

Optionally, the third on-off sub-circuit includes a fifth transistor.

A gate of the fifth transistor is connected with a fifth control signal terminal, a first electrode of the fifth transistor is connected with the first electrode of the first photosensitive element, and a second electrode of the fifth transistor is connected with one terminal of the first capacitor.

Optionally, the charging circuit further includes a sensing sub-circuit50.

The sensing sub-circuit is configured to sense a light intensity of ambient light in an environment where the charging circuit is located and output a light intensity sensing signal to a controller based on the light intensity, so that the controller controls, based on the light intensity sensing signal, time periods when one or more of the third on-off sub-circuit and the second on-off sub-circuit are in the on state.

Optionally, the sensing sub-circuit includes a second photosensitive element.

Optionally, the charging sub-circuit includes a battery.

In still another aspect, a method for driving a texture detection circuit is provided. The texture detection circuit includes a first photosensitive element and a switching sub-circuit, and the method for driving the texture detection circuit includes a charging stage and a texture detection stage.

At the texture detection stage, the switching sub-circuit is controlled to connect a second electrode of the first photosensitive element with a reverse power end.

At the charging stage, the switching sub-circuit is controlled to connect the second electrode of the first photosensitive element with a charging sub-circuit.

Optionally, the texture detection circuit further includes a first on-off sub-circuit, and the method for driving the texture detection circuit further includes:

at the texture detection stage, controlling the first on-off sub-circuit to connect a first electrode of the first photosensitive element with a signal readout line; and

at the charging stage, controlling the first on-off sub-circuit to disconnect the first electrode of the first photosensitive element from the signal readout line.

In still another aspect, a method for driving a charging circuit is provided. The charging circuit includes a charging sub-circuit and a texture detection circuit, the texture detection circuit includes a first photosensitive element and a switching sub-circuit, and the method for driving the charging circuit includes:

at a charging stage, controlling the switching sub-circuit to connect a second electrode of the first photosensitive element with the charging sub-circuit, so that the first photosensitive element provides an electrical signal to the charging sub-circuit and the charging sub-circuit stores the electrical signal in form of electric energy, where the electrical signal is acquired after the first photosensitive element coverts a detected optical signal.

Optionally, the charging circuit further includes a first capacitor, a third on-off sub-circuit and a second on-off sub-circuit. The third on-off sub-circuit and the second on-off sub-circuit are connected in series between the first electrode of the first photosensitive element and the charging sub-circuit sequentially, and one terminal of the first capacitor is connected in series between the third on-off sub-circuit and the second on-off sub-circuit. The charging stage includes a first charging sub-stage and a second charging sub-stage.

At the first charging sub-stage, the third on-off sub-circuit is controlled to connect the first electrode of the first photosensitive element with one terminal of the first capacitor, so that the first photosensitive element charges the first capacitor.

At the second charging sub-stage, the second on-off sub-circuit is controlled to connect one terminal of the first capacitor with the charging sub-circuit, so that the first capacitor discharges to the charging sub-circuit.

A time period when the third on-off sub-circuit is in an on state and a time period when the second on-off sub-circuit is in an on state are non-overlapping.

In still another aspect, a touch display panel is provided. The touch display panel includes a charging circuit and a plurality of pixel units arranged in an array, and the charging circuit is any charging circuit described in the second aspect.

The charging circuit includes a texture detection circuit, and the texture detection circuit is disposed in a part of the pixel units or texture detection circuits are disposed in all of the pixel units.

Optionally, the texture detection circuit is disposed in each pixel unit, and the texture detection circuits in the plurality of pixel units are connected in series.

Optionally, the touch display panel further includes a controller, and the charging circuit further includes a sensing sub-circuit, a second on-off sub-circuit and a third on-off sub-circuit.

The sensing sub-circuit is configured to sense a light intensity of ambient light in an environment where the charging circuit is located and output a light intensity sensing signal to the controller based on the light intensity.

The controller is configured to control, based on the light intensity sensing signal, time periods when one or more of the third on-off sub-circuit and the second on-off sub-circuit are in the on state.

