Input/output device and driving method thereof
View Patent ↗An input/output device includes a pixel area; a light emission circuit provided in the pixel area and configured to emit light; and a photodetection circuit provided in the pixel area and configured to generate a voltage having a value corresponding to an intensity of incident light. The light emission circuit includes a drive transistor and a light emitting element. The light emitting element includes a first current terminal electrically connected to the source or the drain of the drive transistor and a second current terminal to which a first voltage is input, and emits light in accordance with a current flowing between the first and second current terminals. The light emission circuit includes a switching element including a first terminal to which a second voltage is input, and a second terminal electrically connected to the first current terminal of the light emitting element.
1. An input/output device comprising:
a pixel area including a first light emission circuit, a second light emission circuit, and a photodetection circuit, wherein the photodetection circuit is configured to generate a voltage having a value corresponding to an intensity of incident light,
each of the first light emission circuit and the second light emission circuit comprising:
a drive transistor comprising a source, a drain, and a gate; and
a light emitting element comprising a first current terminal and a second current terminal, wherein the first current terminal is electrically connected to the source or the drain of the drive transistor, wherein a first voltage is input to the second current terminal, and wherein the light emitting element emits light in accordance with a current flowing between the first current terminal and the second current terminal;
the second light emission circuit comprising:
a switching element comprising a first terminal and a second terminal, wherein a second voltage is input to the first terminal, wherein the second terminal is electrically connected to the first current terminal of the light emitting element, and wherein, when an object to be detected is over the pixel area, light emitted from the second light emission circuit is reflected by the object to be detected, and light reflected by the object to be detected enters the photodetection circuit.
2. The input/output device according to claim 1 , wherein each of the first light emission circuit and the second light emission circuit comprises a coloring layer transmitting light of a particular color emitted from the light emitting element.
3. The input/output device according to claim 1 , wherein the input/output device is incorporated in one of a mobile information terminal and a stationary information terminal.
4. A method for driving an input/output device comprising:
a pixel area including a first light emission circuit, a second light emission circuit, and a photodetection circuit, wherein the photodetection circuit is configured to generate a voltage having a value corresponding to an intensity of incident light,
each of the first light emission circuit and the second light emission circuit comprising:
a drive transistor comprising a source, a drain, and a gate;
a light emitting element comprising a first current terminal and a second current terminal, wherein the first current terminal is electrically connected to the source or the drain of the drive transistor, wherein a first voltage is input to the second current terminal, and wherein the light emitting element emits light in accordance with a current flowing between the first current terminal and the second current terminal; and
the second light emission circuit comprising:
a switching element comprising a first terminal and a second terminal, wherein a second voltage is input to the first terminal, wherein the second terminal is electrically connected to the first current terminal of the light emitting element;
the method for driving the input/output device comprising the steps of:
inputting a display data signal to each of the first light emission circuit and the second light emission circuit to set a voltage of the gate of the drive transistor to a value corresponding to a voltage of the display data signal;
switching the switching element in the second light emission circuit to an on state; and
generating an optical data which is a voltage having a value corresponding to an intensity of light entering the photodetection circuit when the switching element is in the on state.
5. A method for driving an input/output device comprising:
a pixel area including a first light emission circuit, a second light emission circuit, and a photodetection circuit, wherein the photodetection circuit is configured to generate a voltage having a value corresponding to an intensity of incident light,
each of the first light emission circuit and the second light emission circuit comprising:
a drive transistor comprising a source, a drain, and a gate;
a light emitting element comprising a first current terminal and a second current terminal, wherein the first current terminal is electrically connected to the source or the drain of the drive transistor, wherein a first voltage is input to the second current terminal, and wherein the light emitting element emits light in accordance with a current flowing between the first current terminal and the second current terminal; and
the second light emission circuit comprising:
a switching element comprising a first terminal and a second terminal, wherein a second voltage is input to the first terminal, wherein the second terminal is electrically connected to the first current terminal of the light emitting element;
the method for driving the input/output device comprising the steps of:
inputting a display data signal to each of the first light emission circuit and the second light emission circuit to set a voltage of the gate of the drive transistor to a value corresponding to a voltage of the display data signal;
switching the switching element in the second light emission circuit to an on state; and
generating a first optical data which is a voltage having a value corresponding to an intensity of light entering the photodetection circuit when the switching element is in the on state;
generating a second optical data which is a voltage having a value corresponding to an intensity of light entering the photodetection circuit when the switching element is in an off state; and
generating data of a difference between the first optical data and the second optical data.