Display device including light sensing pixel

1 . A display device comprising:

a display panel comprising a light-emitting pixel comprising a light-emitting element, and a light-sensing pixel comprising an organic photodiode, and configured to reset the organic photodiode to a reset voltage in response to a global reset signal;

a data driver configured to provide a data signal to the light-emitting pixel;

a scan driver configured to provide a scan signal to the light-emitting pixel and to the light-sensing pixel; and

a readout circuit connected to the light-sensing pixel through a readout line, and configured to change at least one of the global reset signal or the reset voltage between a first sensing mode and a second sensing mode,

wherein the first sensing mode is a fingerprint-sensing mode, and the second sensing mode is a photoplethysmography-sensing mode,

wherein, in the fingerprint-sensing mode, the light-emitting pixel in a first sensing region is configured to emit light, and the light-sensing pixel in the first sensing region is configured to sense reflected light, and

wherein, in the photoplethysmography-sensing mode, the light-emitting pixel in an adjacent region adjacent to a second sensing region is configured to emit light, and the light-sensing pixel in the second sensing region is configured to sense reflected light.

2 . The display device of claim 1 , wherein the readout circuit is configured to change a voltage level of the reset voltage between the fingerprint-sensing mode and the photoplethysmography-sensing mode.

3 . The display device of claim 2 , wherein, in a normal mode, the readout circuit is configured to set the reset voltage to a first voltage level,

wherein, in the fingerprint-sensing mode, the readout circuit is configured to set the reset voltage to a second voltage level that is different from the first voltage level, and

wherein, in the photoplethysmography-sensing mode, the readout circuit is configured to set the reset voltage to a third voltage level that is different from the first and second voltage levels.

4 . The display device of claim 3 , wherein the second voltage level is lower than the first voltage level, and

wherein the third voltage level is higher than the first voltage level.

5 . The display device of claim 1 , wherein the readout circuit is configured to change a voltage level of a low gate voltage of the global reset signal between the fingerprint-sensing mode and the photoplethysmography-sensing mode.

6 . The display device of claim 5 , wherein, in a normal mode, the readout circuit is configured to set the low gate voltage of the global reset signal to a first voltage level,

wherein, in the fingerprint-sensing mode, the readout circuit is configured to set the low gate voltage of the global reset signal to a second voltage level that is different from the first voltage level, and

wherein, in the photoplethysmography-sensing mode, the readout circuit is configured to set the low gate voltage of the global reset signal to the first voltage level.

7 . The display device of claim 1 , wherein the readout circuit is configured to change a timing of a low gate voltage of the global reset signal between the fingerprint-sensing mode and the photoplethysmography-sensing mode.

8 . The display device of claim 7 , wherein, in the fingerprint-sensing mode, the readout circuit is configured to provide the global reset signal having a high gate voltage to the light-sensing pixel during a first frame period, and

wherein, in the photoplethysmography-sensing mode, the readout circuit is configured to provide the global reset signal having the high gate voltage to the light-sensing pixel during a portion of a second frame period.

9 . The display device of claim 1 , wherein the readout circuit is configured to change at least one of a waveform or a slew rate of the global reset signal between the fingerprint-sensing mode and the photoplethysmography-sensing mode.

10 . The display device of claim 1 , wherein the light-emitting pixel comprises:

a first transistor configured to generate a driving current;

the light-emitting element configured to emit light based on the driving current;

a second transistor configured to transfer the data signal in response to a write signal;

a third transistor configured to diode-connect the first transistor in response to a compensation signal;

a fourth transistor configured to transfer an initialization voltage to a gate of the first transistor in response to an initialization signal;

a fifth transistor configured to connect a line that is configured to transfer a first power supply voltage and the first transistor in response to an emission signal;

a sixth transistor configured to connect the first transistor and the light-emitting element in response to the emission signal;

a seventh transistor configured to transfer an anode initialization voltage to the light-emitting element in response to a bypass signal;

an eighth transistor configured to transfer a bias voltage to one terminal of the first transistor in response to the bypass signal; and

a storage capacitor connected between the line that is configured to transfer the first power supply voltage and the gate of the first transistor.

11 . The display device of claim 10 , wherein the light-sensing pixel comprises:

a ninth transistor configured to generate a sensing current based on a voltage of an anode of the organic photodiode;

a tenth transistor configured to transfer the reset voltage to the anode of the organic photodiode in response to the global reset signal;

an eleventh transistor configured to connect the ninth transistor and the readout line in response to the write signal; and

the organic photodiode.

12 . The display device of claim 11 , wherein the ninth transistor comprises a gate connected to the organic photodiode, a first terminal that is configured to receive a sensing reference voltage, and a second terminal,

wherein the tenth transistor comprises a gate that is configured to receive the global reset signal, a first terminal that is configured to receive the reset voltage, and a second terminal connected to the anode of the organic photodiode,

wherein the eleventh transistor comprises a gate that is configured to receive the write signal, a first terminal connected to the second terminal of the ninth transistor, and a second terminal connected to the readout line, and

wherein the anode of the organic photodiode is connected to the gate of the ninth transistor, and a cathode of the organic photodiode is connected to a line that is configured to transfer a second power supply voltage.

13 . The display device of claim 1 , wherein the readout circuit comprises:

a global reset circuit configured to generate the global reset signal;

a sensing circuit configured to receive a sensing current of the light-sensing pixel through the readout line, and to generate a digital sensing signal corresponding to the sensing current; and

a register configured to store setting values for the global reset signal and the reset voltage in a normal mode, the first sensing mode, and the second sensing mode.

14 . The display device of claim 13 , wherein the sensing circuit comprises:

an amplifier comprising an inverting input terminal connected to the readout line, a non-inverting input terminal that is configured to receive a reference voltage, and an output terminal;

an integrating capacitor connected between the inverting input terminal and the output terminal of the amplifier;

a reset switch configured to reset the integrating capacitor;

a noise capacitor configured to store a noise voltage output from the amplifier;

a noise switch configured to selectively connect the output terminal of the amplifier and the noise capacitor;

a signal capacitor configured to store a signal voltage output from the amplifier;

a signal switch configured to selectively connect the output terminal of the amplifier and the signal capacitor; and

an analog-to-digital converter configured to generate the digital sensing signal based on a difference between the noise voltage and the signal voltage.

15 . An electronic device comprising:

a processor configured to provide input image data; and

a display device configured to receive the input image data from the processor, and to display an image based on the input image data, the display device comprising:

a display panel comprising a light-emitting pixel comprising a light-emitting element, and a light-sensing pixel comprising an organic photodiode, and configured to reset the organic photodiode to a reset voltage in response to a global reset signal;

a data driver configured to provide a data signal to the light-emitting pixel;

a scan driver configured to provide a scan signal to the light-emitting pixel and to the light-sensing pixel; and

a readout circuit connected to the light-sensing pixel through a readout line, and configured to change a voltage level of the reset voltage among a normal mode, a fingerprint-sensing mode, and a photoplethysmography-sensing mode,

wherein, in the fingerprint-sensing mode, the light-emitting pixel in a first sensing region is configured to emit light, and the light-sensing pixel in the first sensing region is configured to sense reflected light, and

wherein, in the photoplethysmography-sensing mode, the light-emitting pixel in an adjacent region adjacent to a second sensing region is configured to emit light, and the light-sensing pixel in the second sensing region is configured to sense reflected light.

16 . The electronic device of claim 15 , wherein, in the normal mode, the readout circuit is configured to set the reset voltage to a first voltage level,

wherein, in the fingerprint-sensing mode, the readout circuit is configured to set the reset voltage to a second voltage level that is different from the first voltage level, and

wherein, in the photoplethysmography-sensing mode, the readout circuit is configured to set the reset voltage to a third voltage level that is different from the first and second voltage levels.

17 . An electronic device comprising:

a processor configured to provide input image data; and

a display device configured to receive the input image data from the processor, and to display an image based on the input image data, the display device comprising:

a display panel comprising a light-emitting pixel comprising a light-emitting element, and a light-sensing pixel comprising an organic photodiode and configured to reset the organic photodiode to a reset voltage in response to a global reset signal;

a data driver configured to provide a data signal to the light-emitting pixel;

a scan driver configured to provide a scan signal to the light-emitting pixel and to the light-sensing pixel; and

a readout circuit connected to the light-sensing pixel through a readout line, and configured to change at least one of a voltage level, a timing, a waveform, or a slew rate of the global reset signal among a normal mode, a fingerprint-sensing mode, and a photoplethysmography-sensing mode,

wherein, in the fingerprint-sensing mode, the light-emitting pixel in a first sensing region is configured to emit light, and the light-sensing pixel in the first sensing region is configured to sense reflected light, and

wherein, in the photoplethysmography-sensing mode, the light-emitting pixel in an adjacent region adjacent to a second sensing region is configured to emit light, and the light-sensing pixel in the second sensing region is configured to sense reflected light.

18 . The electronic device of claim 17 , wherein, in the normal mode, the readout circuit is configured to set a low gate voltage of the global reset signal to a first voltage level,

wherein, in the fingerprint-sensing mode, the readout circuit is configured to set the low gate voltage of the global reset signal to a second voltage level that is different from the first voltage level, and

wherein, in the photoplethysmography-sensing mode, the readout circuit is configured to set the low gate voltage of the global reset signal to the first voltage level.

19 . The electronic device of claim 17 , wherein, in the fingerprint-sensing mode, the readout circuit is configured to provide the global reset signal having a high gate voltage to the light-sensing pixel during a first frame period, and

wherein, in the photoplethysmography-sensing mode, the readout circuit is configured to provide the global reset signal having the high gate voltage to the light-sensing pixel during a portion of a second frame period.