According to one embodiment, a display device includes a display panel having a counter substrate, an array substrate and a liquid crystal layer held therebetween, a counter electrode provided on the counter substrate, a pixel electrode arranged on the array substrate in a matrix, a sensor circuit arranged between rows of the plurality of pixel electrodes and configured to read out intensity of capacitive coupling between the sensor circuit and a dielectric, and a counter electrode drive circuit configured to pulsatively drive a common voltage added to the counter electrode during a period of driving the sensor circuit, wherein the sensor circuit comprises a detection electrode configured to form capacitance between the sensor circuit and the dielectric and to form capacitance between the sensor circuit and the counter electrode, and wherein the counter electrode comprises an aperture including at least a portion opposed to the detection electrode.
1. A display device comprising:
a display panel having a counter substrate, an array substrate and a liquid crystal layer held therebetween;
a counter electrode provided on the counter substrate;
a pixel electrode arranged on the array substrate in a matrix;
a sensor circuit arranged between rows of the plurality of pixel electrodes and configured to read out intensity of capacitive coupling between the sensor circuit and a dielectric; and
a counter electrode drive circuit configured to pulsatively drive a common voltage added to the counter electrode during a period of driving the sensor circuit,
wherein
the sensor circuit comprises a detection electrode configured to form first floating capacitance between the sensor circuit and the dielectric and to form second floating capacitance between the sensor circuit and the counter electrode;
the counter electrode comprises an aperture including at least a portion opposed to the detection electrode;
the first floating capacitance is formed between the dielectric and the detection electrode via the aperture;
a potential of the detection electrode varies via the second floating capacitance by pulsatively driving the common voltage; and
the sensor circuit detects presence or absence of the dielectric based on the potential of the detection electrode when a predetermined time has passed since the counter electrode drive circuit started pulsatively driving the common voltage added to the counter electrode.
2. The display device of claim 1 , comprising:
a precharge line configured to supply a voltage to the detection electrode;
a readout line configured to read out a detection signal from the detection electrode; and
a precharge gate line, an amplification source line and a readout gate line configured to drive the sensor circuit,
wherein the sensor circuit comprises:
a precharge transistor including a gate electrode, a source electrode, and a drain electrode, in which one of the source electrode or the drain electrode of the precharge transistor is connected to the precharge line, the other one of the source electrode or the drain electrode of the precharge transistor is connected to the detection electrode, and the gate electrode of the precharge transistor is connected to the precharge gate line;
an amplification transistor including a gate electrode, a source electrode, and a drain electrode, in which one of the source electrode or the drain electrode of the amplification transistor is connected to the amplification source line, and the gate electrode of the amplification transistor is connected to the detection electrode; and
a readout transistor including a gate electrode, a source electrode, and a drain electrode, in which one of the source electrode or the drain electrode of the readout transistor is connected to the other one of the source electrode or the drain electrode of the amplification transistor, the other one of the source electrode or the drain electrode of the readout transistor is connected to the readout line, and the gate electrode of the readout transistor is connected to the readout gate line.
3. The display device of claim 1 , wherein at least one sensor circuit is arranged in a unit region in which a plurality of pixel circuits are arranged in a plurality of rows and a plurality of columns.
4. The display device of claim 1 , wherein a period of driving the sensor circuit is included in a horizontal blanking period.
5. The display device of claim 1 , wherein a period of driving the sensor circuit is included in a vertical blanking period.
6. The display device of claim 1 , further comprising a time detection module configured to detect a time where an output signal of the sensor circuit reaches a reference voltage.
7. The display device of claim 6 , further comprising an adjustment module configured to adjust a time where an output signal of the sensor circuit reaches the reference voltage by controlling the precharge voltage.