Input sensing method and input sensing device including the same
An input sensing device includes: sensor pixels, a horizontal driver, a selection circuit, and a vertical driver. Each of the sensor pixels is connected to a plurality of driving lines and a one of a plurality of signal input lines. The horizontal driver sequentially applies a horizontal driving signal to the sensor pixels through the driving lines. The selection circuit is connected to n of the signal input lines (n is a natural number of 2 or more) and to one output line. The selection circuit sequentially outputs n sensing signals received through the n signal input lines to the one output line. The vertical driver receives the n sensing signals through the one output line. The horizontal driver applies the horizontal driving signal n times to a given one of the driving lines to correspond to the n sensing signals.
1 . A display device comprising:
a first sensor pixel connected to a first signal input line extending in a first direction and a horizontal driving line extending in a second direction crossing the first direction;
a second sensor pixel connected to a second signal input line different from the first signal input line and connected to the horizontal driving line; and
a multiplexer,
wherein during a sensing period within a single frame period, a gate-on voltage is applied to the horizontal driving line a plurality of times,
wherein during a first period within the sensing period, in which a first application of the gate-on voltage is applied a first one of the plurality of times, the multiplexer electrically connects the first signal input line to an output line and disconnects the second signal input line from the output line,
wherein during a second period, subsequent to the first period within the sensing period, in which a second application of the gate-on voltage is applied a second one of the plurality of times, the multiplexer disconnects the first signal input line from the output line and electrically connects the second signal input line to the output line, and
wherein a gate-off voltage is applied to the horizontal driving line throughout a period between the first and second applications of the gate-on voltage.
2 . The display device of claim 1 , wherein each of the first sensor pixel and the second sensor pixel includes a first node, a second node, and a third node, wherein the first sensor pixel comprises:
a first transistor including a gate electrode connected to a reset line and configured to switch an electrical connection between a first power line and the first node;
a second transistor including a gate electrode connected to the first node and configured to switch an electrical connection between a third power line and the second node;
a third transistor including a gate electrode connected to the horizontal driving line and configured to switch an electrical connection between the second node and the first signal input line; and
a photodiode connected between the first node and a second power line, and wherein the second sensor pixel comprises:
a first transistor including a gate electrode connected to the reset line and configured to switch the electrical connection between the first power line and the first node;
a second transistor including a gate electrode connected to the first node and configured to switch the electrical connection between the third power line and the second node;
a third transistor including a gate electrode connected to the horizontal driving line and configured to switch an electrical connection between the second node and the second signal input line; and
a photodiode connected between the first node and the second power line.
3 . The display device of claim 2 , wherein each of the first sensor pixel and the second sensor pixel further comprises: a capacitor including a first electrode connected to the second power line and a second electrode connected to the first node.
4 . The display device of claim 3 , wherein when the gate-on voltage is applied to the horizontal driving line the plurality of times, a voltage is applied the plurality of times to the first signal input line from the capacitor of the first sensor pixel, and a voltage is applied the plurality of times to the second signal input line from the capacitor of the second sensor pixel.
5 . The display device of claim 2 , wherein each of the first to third power lines extends in the first direction.
6 . The display device of claim 2 , wherein the first transistor of the first sensor pixel and the second transistor of the second sensor pixel are turned on in response to a same signal.
7 . The display device of claim 1 , wherein the first sensor pixel and the second sensor pixel are adjacent to each other in the second direction.
8 . The display device of claim 1 , wherein the multiplexer comprises:
a first selection transistor configured to electrically connect or disconnect the first signal input line to or from the output line; and
a second selection transistor configured to electrically connect or disconnect the second signal input line to or from the output line.
9 . The display device of claim 8 , wherein during the period in which the gate-on voltage is applied to the horizontal driving line the plurality of times, each of the first selection transistor and the second selection transistor is turned on once.
10 . The display device of claim 9 , wherein the first selection transistor and the second selection transistor are continuously turned on.
11 . The display device of claim 8 , further comprising an integration circuit, wherein the integration circuit comprises:
an amplifier including a first input terminal connected to the output line, a second input terminal connected to a reference voltage line, and an output terminal;
a capacitor including a first electrode connected to the first input terminal and a second electrode connected to the output terminal; and
an initialization switch disposed between the first input terminal and the output terminal.
12 . The display device of claim 11 further comprising a correlated double sampling circuit, wherein the correlated double sampling circuit comprises:
a first sampling switch connected to the output terminal;
a second sampling switch different from the first sampling switch and connected to the output terminal;
a first sampling capacitor including one terminal connected to the first sampling switch;
a second sampling capacitor including one terminal connected to the second sampling switch; and
a differential amplifier including a first input terminal connected to the one terminal of the first sampling capacitor, and a second input terminal connected to the one terminal of the second sampling capacitor.
13 . The display device of claim 12 , wherein each of the first selection transistor and the second selection transistor is turned on before the first sampling switch is turned on, and is turned off after the second sampling switch is turned off.
14 . The display device of claim 11 , wherein each of the first selection transistor and the second selection transistor is turned on before the initialization switch is turned on.
15 . A driving method of a display device, the method comprising:
during a sensing period within a single frame period, applying a gate-on voltage to a horizontal driving line connected to a first sensor pixel and a second sensor pixel a plurality of times, wherein the horizontal driving line extends in a second direction;
during a first period within the sensing period in which a first application of the gate-on voltage is applied a first one of the plurality of times, electrically connecting a first signal input line connected to the first sensor pixel to an output line, and disconnecting a second signal input line connected to the second sensor pixel from the output line, wherein each of the first signal input line and the second signal input line extends in a first direction crossing the second direction;
during a second other period within the sensing period in which a second application of the gate-on voltage is applied a second one of the plurality of times, disconnecting the first signal input line from the output line, and electrically connecting the second signal input line to the output line, and
wherein a gate-off voltage is applied to the horizontal driving line throughout a period between the first and second applications of the gate-on voltage.
16 . The driving method of claim 15 , wherein, in the period of electrically connecting the first signal input line to the output line and disconnecting the second signal input line from the output line, a voltage is applied from the first sensor pixel to the first signal input line, and a voltage is applied from the second sensor pixel to the second signal input line.
17 . The driving method of claim 16 , wherein the voltage applied from the first sensor pixel to the first signal input line is a voltage generated by a photodiode of the first sensor pixel, and wherein the voltage applied from the second sensor pixel to the second signal input line is a voltage generated by a photodiode of the second sensor pixel.
18 . A display device comprising:
a first sensor pixel connected to a first signal input line extending in a first direction and a horizontal driving line extending in a second direction crossing the first direction;
a second sensor pixel connected to a second signal input line different from the first signal input line and connected to the horizontal driving line;
a multiplexer including a first selection transistor and a second selection transistors, wherein the selection transistor is configured to switch an electrical connection between the first signal input line and an output line, and wherein the second selection transistor is configured to switch an electrical connection between the second signal input line and the output line;
a first sampling switch connected to an output terminal; and
a second sampling switch different from the first sampling switch and connected to the output terminal,
wherein during a sensing period, a gate-on voltage is applied to the horizontal driving line a plurality of times,
wherein during a period in which the gate-on voltage is applied to the horizontal driving line the plurality of times, each of the first signal input line and the second signal input line is electrically connected to the output line once, and
wherein each of the first selection transistor and the second selection transistor is turned on before the first sampling switch is turned on, and is turned off after the second sampling switch is turned off.
19 . The display device of claim 18 , further comprising:
a first sampling capacitor including one terminal connected to the first sampling switch;
a second sampling capacitor including one terminal connected to the second sampling switch; and
a differential amplifier including a first input terminal connected to the one terminal of the first sampling capacitor, and a second input terminal connected to the one terminal of the second sampling capacitor.