Panel for fingerprint identification, and control method thereof, and apparatus for fingerprint identification

1. A panel for fingerprint identification, comprising: a display unit, a control unit, and a unit for adjusting light transmittance and a unit for fingerprint identification which are disposed on a backlight side of the display unit, the unit for adjusting light transmittance being disposed on a side of the unit for fingerprint identification close to the display unit, and an operating state of the panel for fingerprint identification comprising a display stage and a fingerprint identification stage; wherein,

at the display stage,

the display unit is configured to emit first light to display an image to be displayed,

the unit for adjusting light transmittance is configured to transmit light transmitted through the display unit, and

the control unit being connected with the unit for adjusting light transmittance is configured to control light transmittance of the unit for adjusting light transmittance so that the light transmittance of the unit for adjusting light transmittance is less than or equal to a threshold of light transmittance;

wherein at the fingerprint identification stage,

the display unit is configured to emit second light to a fingerprint to be detected,

the unit for adjusting light transmittance is configured to transmit the second light reflected by the fingerprint to be detected,

the control unit is configured to control the light transmittance of the unit for adjusting light transmittance so that the light transmittance of the unit for adjusting light transmittance is greater than the threshold of light transmittance, and

the unit for fingerprint identification is configured to receive light transmitted through the unit for adjusting light transmittance and obtain a fingerprint image according to the light transmitted through the unit for adjusting light transmittance to identify a fingerprint.

2. The panel for fingerprint identification according to claim 1 , wherein the control unit is configured to generate a first control signal at the display stage, and control the light transmittance of the unit for adjusting light transmittance according to the first control signal, so that the light transmittance of the unit for adjusting light transmittance is less than or equal to the threshold of light transmittance.

3. The panel for fingerprint identification according to claim 2 , wherein the control unit is configured to generate a second control signal at the fingerprint identification stage, and control the light transmittance of the unit for adjusting light transmittance according to the second control signal, so that the light transmittance of the unit for adjusting light transmittance is greater than the threshold of light transmittance.

4. The panel for fingerprint identification according to claim 3 , wherein the unit for fingerprint identification comprises: a substrate and multiple photoelectric sensors disposed on the substrate; and

the multiple photoelectric sensors are disposed on a side of the substrate close to the display unit.

5. The panel for fingerprint identification according to claim 3 , wherein the display unit comprises: multiple point light sources, and the multiple point light sources sequentially emit light at the fingerprint identification stage.

6. The panel for fingerprint identification according to claim 5 , wherein the unit for adjusting light transmittance comprises: multiple structures for adjusting light transmittance, wherein the multiple structures for adjusting light transmittance correspond to the multiple point light sources one by one;

an orthographic projection of the structures for adjusting light transmittance on the display unit covers an orthographic projection of the point light sources corresponding to the structures for adjusting light transmittance on the display unit; and

the control unit is connected with each structure for adjusting light transmittance, and is configured to control light transmittance of each structure for adjusting light transmittance.

7. The panel for fingerprint identification according to claim 6 , wherein each structure for adjusting light transmittance comprises: a first electrode and a second electrode, and a layer for adjusting light transmittance disposed between the first electrode and the second electrode;

the control unit is connected with the first electrode and the second electrode; and

the control unit is configured to:

at the display stage, provide electric signals to the first electrode and the second electrode according to a first control signal and form a first electric field between the first electrode and the second electrode so that light transmittance of the layer for adjusting light transmittance is less than or equal to the threshold of light transmittance under a role of the first electric field; and

at the fingerprint identification stage, provide electrical signals to the first electrode and the second electrode according to a second control signal, and form a second electric field between the first electrode and the second electrode so that the light transmittance of the layer for adjusting light transmittance is greater than the threshold of light transmittance under a role of the second electric field.

8. The panel for fingerprint identification according to claim 7 , wherein the first electrode and the second electrode are transmissive electrodes.

9. The panel for fingerprint identification according to claim 8 , wherein first electrodes of adjacent structures for adjusting light transmittance are spaced apart, and second electrodes of adjacent structures for adjusting light transmittance are spaced apart.

10. The panel for fingerprint identification according to claim 9 , wherein an i-th point light source corresponds to an i-th structure for adjusting light transmittance; and

under a state that the i-th point light source emits light, the control unit is configured to, at the fingerprint identification stage, control light transmittance of the i-th structure for adjusting light transmittance to be first light transmittance according to the second control signal, and control light transmittance of all other structures for adjusting light transmittance except the i-th structure for adjusting light transmittance to be second light transmittance, wherein the first light transmittance is less than or greater than the second light transmittance, 1≤i≤N, and the N is a quantity of point light sources.

11. The panel for fingerprint identification according to claim 8 , wherein first electrodes of adjacent structures for adjusting light transmittance are connected to each other, and second electrodes of adjacent structures for adjusting light transmittance are connected to each other.

12. The panel for fingerprint identification according to claim 7 , wherein the layer for adjusting light transmittance is a liquid crystal layer; and

the liquid crystal layer comprises: a holographic polymer dispersed liquid crystal Bragg grating or a cholesteric liquid crystal.

13. The panel for fingerprint identification according to claim 7 , wherein the layer for adjusting light transmittance is a color change layer; and

a preparation material of the color change layer comprises: polyaniline, viologen, tungsten trioxide, polythiophenes and derivatives thereof, viologen compounds, tetrathiafulvalene or metal phthalocyanine compounds.

14. The panel for fingerprint identification according to claim 1 , wherein the panel for fingerprint identification further comprises: a collimating layer;

the collimating layer is disposed on a side of the unit for adjusting light transmittance close to the display unit, and is configured to filter incident light, so that light with a scattering angle within a threshold range is emitted toward the unit for adjusting light transmittance; and

the incident light is the light transmitted through the display unit at the display stage, and the second light reflected by the fingerprint to be detected at the fingerprint identification stage.

15. The panel for fingerprint identification according to claim 1 , wherein the unit for fingerprint identification is disposed on a side of the unit for adjusting light transmittance remote from the display unit by an optical adhesive.

16. The panel for fingerprint identification according to claim 15 , wherein the display unit comprises: an organic light emitting diode display substrate.

17. An apparatus for fingerprint identification, comprising: the panel for fingerprint identification according to claim 1 .