Image sensor and display device having the same
An image sensor includes a sensor pixel. The sensor pixel includes a first transistor coupled between a first power source and a first node, where the first transistor is turned on in response to a first control signal, a light-sensing element coupled between the first node and a second power source, where the light-sensing element generates photocharges in response to incident light, a storage capacitor coupled in parallel to the light-sensing element between the first node and the second power source, and an amplifier including a plurality of transistors coupled in series between the first power source and an output line, where the amplifier outputs a sensing signal corresponding to a voltage of the first node in response to a first driving signal.
1. An image sensor comprising:
a sensor pixel including:
a first transistor coupled between a first power source and a first node, wherein the first transistor is turned on in response to a first control signal;
a light-sensing element coupled between the first node and a second power source, wherein the light-sensing element generates photocharges in response to incident light;
a storage capacitor coupled in parallel to the light-sensing element between the first node and the second power source; and
an amplifier including a plurality of transistors coupled in series between the first power source and an output line, wherein the amplifier outputs a sensing signal corresponding to a voltage of the first node in response to a first driving signal.
2. The image sensor according to claim 1 , wherein the amplifier comprises:
a second transistor coupled between the first power source and the output line, wherein the second transistor includes a gate electrode coupled to the first node and generates the sensing signal; and
a third transistor coupled between the second transistor and the output line, wherein the third transistor amplifies and outputs the sensing signal during an interval in which the first driving signal is supplied.
3. The image sensor according to claim 1 , wherein, during each cycle of a sensing period in which the sensor pixel is activated, the first control signal and the first driving signal are sequentially supplied to the sensor pixel at an interval of a predetermined time.
4. The image sensor according to claim 1 , wherein the light-sensing element is a photodiode.
5. The image sensor according to claim 1 , wherein the sensor pixel further comprises a transfer transistor coupled between the first node and the light-sensing element, wherein the transfer transistor is turned on in response to a second control signal.
6. The image sensor according to claim 5 , wherein
the first and second control signals are sequentially supplied to the sensor pixel during each cycle of a sensing period during which the sensor pixel is activated, and
the first driving signal is individually supplied subsequent to the first and second control signals a plurality of times during each cycle.
7. A display device comprising:
a display panel including a display pixel; and
an image sensor including a sensor pixel,
wherein the sensor pixel comprises:
a first transistor coupled between a first power source and a first node, wherein the first transistor is turned on in response to a first control signal;
a light-sensing element coupled between the first node and a second power source, wherein the light-sensing element generates photocharges in response to incident light;
a storage capacitor coupled in parallel to the light-sensing element between the first node and the second power source; and
an amplifier including a plurality of transistors coupled in series between the first power source and an output line, wherein the amplifier outputs a sensing signal corresponding to a voltage of the first node in response to a first driving signal.
8. The display device according to claim 7 , wherein the amplifier comprises:
a second transistor coupled between the first power source and the output line, wherein the second transistor includes a gate electrode coupled to the first node to generate the sensing signal; and
a third transistor coupled between the second transistor and the output line, wherein the third transistor amplifies and outputs the sensing signal during an interval in which the first driving signal is supplied.
9. The display device according to claim 7 , wherein, during each cycle of a sensing period in which the sensor pixel is activated, the first control signal and the first driving signal are sequentially supplied to the sensor pixel at an interval of a predetermined time.
10. The display device according to claim 7 , wherein the sensor pixel further comprises a transfer transistor coupled between the first node and the light-sensing element, wherein the transfer transistor is turned on in response to a second control signal.
11. The display device according to claim 7 , wherein
the image sensor is arranged on a rear surface of the display panel, and
the sensor pixel is arranged in a sensing area which overlaps a portion of a display area in which the display pixel is arranged.