Pixel circuit, display device including the same and electronic device including the same
A pixel circuit includes a light emitter including an emission driving transistor to output a driving current based on a data voltage, a write transistor to apply the data voltage to the emission driving transistor in response to a write gate signal, and a light-emitting element to emit light based on the driving current, and a light sensor to sense the light, and including a sensing driving transistor including a first control electrode for receiving a reset voltage and a sensing voltage, and a second control electrode for receiving an adjustable photodiode voltage, for generating a sensing current in response to the sensing voltage, a sensing initialization transistor to apply the reset voltage to the first control electrode in response to a photo initialization gate signal, and a sensing output transistor to apply the sensing current to a sensing line in response to an output gate signal.
1 . A pixel circuit comprising:
a light emitter configured to emit light, and comprising:
an emission driving transistor configured to output a driving current based on a data voltage;
a write transistor configured to apply the data voltage to the emission driving transistor in response to a write gate signal; and
a light-emitting element configured to emit light based on the driving current; and
a light sensor configured to sense the light of the light emitter, and comprising:
a sensing driving transistor comprising a first control electrode for receiving a reset voltage and a sensing voltage, and a second control electrode for receiving an adjustable photodiode voltage, and configured to generate a sensing current in response to the sensing voltage, the photodiode voltage being configured to be changed based on the sensing current;
a sensing initialization transistor configured to apply the reset voltage to the first control electrode of the sensing driving transistor in response to a photo initialization gate signal; and
a sensing output transistor configured to apply the sensing current to a sensing line in response to an output gate signal,
wherein the photodiode voltage is configured to be changed based on a sensing code corresponding to the sensing current.
2 . The pixel circuit of claim 1 , wherein the photodiode voltage is configured to have a voltage level that is lower than a reference photodiode voltage when a number of the sensing code is lower than a number of an initial sensing code.
3 . The pixel circuit of claim 2 , wherein the initial sensing code is configured to be set in a manufacturing process.
4 . The pixel circuit of claim 2 , wherein the reference photodiode voltage is configured to be set based on an initial threshold voltage of the sensing driving transistor and the initial sensing code.
5 . The pixel circuit of claim 1 , wherein the sensing current is based on the sensing voltage and the photodiode voltage.
6 . The pixel circuit of claim 1 , wherein the light emitter further comprises a light-emitting element initialization transistor configured to apply a light-emitting element initialization voltage to a first electrode of the light-emitting element, and
wherein a first electrode of the sensing driving transistor is configured to receive the light-emitting element initialization voltage.
7 . The pixel circuit of claim 1 , wherein the output gate signal comprises the write gate signal.
8 . The pixel circuit of claim 1 , wherein the light sensor comprises a photodiode comprising:
a first sub-photodiode configured to generate a first sensing voltage; and
a second sub-photodiode configured to generate a second sensing voltage, and
wherein the light sensor further comprises:
a first transfer transistor configured to apply the first sensing voltage to the first control electrode of the sensing driving transistor in response to a first transfer signal; and
a second transfer transistor configured to apply the second sensing voltage to the first control electrode of the sensing driving transistor in response to a second transfer signal that is different from the first transfer signal.
9 . A pixel circuit comprising:
a light emitter; and
a light sensor comprising:
a photodiode;
a sensing driving transistor comprising a first control electrode connected to a fifth node, a second control electrode for receiving a photodiode voltage, a first electrode for receiving a reference voltage, and a second electrode connected to a sixth node, the photodiode voltage being configured to be changed based on a sensing current through the sixth node;
a sensing initialization transistor comprising a control electrode for receiving a photo initialization gate signal, a first electrode for receiving a reset voltage, and a second electrode connected to the fifth node; and
a sensing output transistor comprising a control electrode for receiving a write gate signal, a first electrode connected to the sixth node, and a second electrode connected to a sensing line,
wherein the photodiode voltage is configured to be changed based on a sensing code corresponding to the sensing current.
10 . The pixel circuit of claim 9 , wherein the photodiode comprises a first electrode connected to the fifth node, and a second electrode for receiving a second power voltage.
11 . The pixel circuit of claim 9 , wherein the light emitter comprises:
a first transistor comprising a control electrode connected to a first node, a first electrode connected to a second node, and a second electrode connected to a third node;
a second transistor comprising a control electrode for receiving the write gate signal, a first electrode for receiving a data voltage, and a second electrode connected to the second node;
a third transistor comprising a control electrode for receiving a compensation gate signal, a first electrode connected to the third node, and a second electrode connected to the first node;
a fourth transistor comprising a control electrode for receiving an initialization gate signal, a first electrode for receiving an initialization voltage, and a second electrode connected to the first node;
a fifth transistor comprising a control electrode for receiving an emission signal, a first electrode for receiving a first power voltage, and a second electrode connected to the second node;
a sixth transistor comprising a control electrode for receiving the emission signal, a first electrode connected to the third node, and a second electrode connected to a fourth node;
a seventh transistor comprising a control electrode for receiving a light-emitting element initialization gate signal, a first electrode for receiving a light-emitting element initialization voltage, and a second electrode connected to the fourth node; and
a light-emitting element comprising a first electrode connected to the fourth node, and a second electrode for receiving a second power voltage, and
wherein the reference voltage comprises the light-emitting element initialization voltage.
12 . The pixel circuit of claim 11 , wherein the photodiode voltage comprises the first power voltage.
13 . The pixel circuit of claim 11 , wherein the write gate signal is configured to swing between a high voltage, and a low voltage that is lower than the high voltage, and
wherein the photodiode voltage comprises the low voltage.
14 . The pixel circuit of claim 9 , wherein the photodiode comprises a first sub-photodiode and a second sub-photodiode, and
wherein the light sensor further comprises:
a first transfer transistor comprising a control electrode for receiving a first transfer signal, a first electrode connected to the fifth node, and a second electrode connected to the first sub-photodiode; and
a second transfer transistor comprising a control electrode for receiving a second transfer signal different from the first transfer signal, a first electrode connected to the fifth node, and a second electrode connected to the second sub-photodiode.
15 . An electronic device comprising:
a display panel comprising a pixel circuit;
a gate driver configured to apply a gate signal to the display panel;
a data driver configured to apply a data voltage to the display panel;
an emission driver configured to apply an emission signal to the display panel; and
a driving controller configured to control the gate driver, the data driver, and the emission driver,
wherein the pixel circuit comprises:
a light emitter configured to emit light, and comprising:
an emission driving transistor configured to output a driving current based on the data voltage;
a write transistor configured to apply the data voltage to the emission driving transistor in response to a write gate signal; and
a light-emitting element configured to emit light based on the driving current; and
a light sensor configured to sense the light of the light emitter, and comprising:
a sensing driving transistor comprising a first control electrode for receiving a reset voltage and a sensing voltage, and a second control electrode for receiving an adjustable photodiode voltage, and configured to generate a sensing current in response to the sensing voltage, the photodiode voltage being configured to be changed based on the sensing current;
a sensing initialization transistor configured to apply the reset voltage to the first control electrode of the sensing driving transistor in response to a photo initialization gate signal; and
a sensing output transistor configured to apply the sensing current to a sensing line in response to an output gate signal,
wherein the photodiode voltage is configured to be changed based on a sensing code corresponding to the sensing current.
16 . The electronic device of claim 15 , wherein the photodiode voltage is configured to have a voltage level that is lower than a reference photodiode voltage when a number of the sensing code is lower than a number of an initial sensing code.
17 . The electronic device of claim 16 , wherein the reference photodiode voltage is configured to be set based on an initial threshold voltage of the sensing driving transistor and the initial sensing code.
18 . The electronic device of claim 15 , wherein the sensing current is configured to be generated based on the sensing voltage and the photodiode voltage.
19 . The electronic device of claim 15 , wherein the sensing initialization transistor comprises a control electrode for receiving the photo initialization gate signal, a first electrode for receiving the reset voltage, and a second electrode connected to a fifth node,
wherein the sensing driving transistor comprises the first control electrode connected to the fifth node, a first electrode for receiving a reference voltage, and a second electrode connected to a sixth node, and
wherein the sensing output transistor comprises a control electrode for receiving the write gate signal, a first electrode connected to the sixth node, and a second electrode connected to the sensing line.