A pixel circuit including: an organic light emitting diode (31, 59); a capacitor (C11, C51); a switching transistor (T12, T52) for, in response to a scan signal (Gate(n)) applied to a scan line, switching a data signal of a voltage level (V data) to be applied to a corresponding data line; a driving transistor (T13, T53) for supplying a drive current to the organic light emitting diode (31, 59) according to a charge voltage corresponding to the data signal input to the driving transistor (T13, T53) via the switching transistor (T12, T52), and wherein the organic light emitting diode (31, 59) is configured to emit light corresponding to the drive current; a second switching transistor (T11, T51) for supplying a power supply voltage (V dd)to the driving transistor (T13, T53) in response to an emission signal (Em); a third switching transistor (T16, T56) for supplying the drive current input via the driving transistor (T13, T53) to the organic light emitting diode (31, 59) in response to the emission signal (Em); and a compensation transistor (T15, T55) for compensating for a threshold voltage of the driving transistor (T13, T53), the pixel circuit further comprising: a photosensor (PD 58) having a cathode terminal to which a high level voltage is applied, wherein the switching transistor (T12, T52) is a dual gate transistor having a first gate connected to an anode terminal of the photosensor, and a second gate connected to a gate of the compensation transistor, and wherein the switching transistor (T12, T52) operates as a readout transistor which reads out a signal from the photosensor (PD 58); wherein the switching transistor (T12, T52) has a source to which the data signal of the voltage level (V data) applied to the corresponding data line is applied, and a drain connected to a source of the driving transistor (T13, T53); wherein the driving transistor (T13, T53) has a gate connected to one terminal of the capacitor (C11, C51), and a drain connected to an anode terminal of the organic light emitting diode (31, 59) via the third switching transistor (T16, T56); wherein the compensation transistor (T15, T55) has a drain connected to the gate of the driving transistor (T13, T53), a source connected to the drain of the driving transistor (T13, T53), and a gate to which the scan signal (Gate(n)) is applied; wherein the second switching transistor (T11, T51) has a gate to which the emission signal (Em) is applied, a source to which the power supply voltage (V dd) is applied, and a drain connected to the source of the driving transistor (T13, T53); wherein the third switching transistor (T16, T56) has a gate to which the emission signal (Em) is applied, a source connected to the drain of the driving transistor (T13, T53), and a drain connected to the anode terminal of the organic light emitting diode (31, 59); wherein the power supply voltage (V dd)of a high level is supplied to the other terminal of the capacitor (C11, C51); and wherein the organic light emitting diode has a cathode terminal connected to a power supply voltage (V ss); and wherein a scan signal for turning on the dual gate transistor is applied to the second gate to charge the data signal applied to the data line, and an adaptively controlled scan signal is applied to the second gate to read out a signal from the photosensor from the data line. a photosensor (PD 58) having a cathode terminal to which a high level voltage is applied, wherein the switching transistor (T12, T52) is a dual gate transistor having a first gate connected to an anode terminal of the photosensor, and a second gate connected to a gate of the compensation transistor, and wherein the switching transistor (T12, T52) operates as a readout transistor which reads out a signal from the photosensor (PD 58); wherein the switching transistor (T12, T52) has a source to which the data signal of the voltage level (V data) applied to the corresponding data line is applied, and a drain connected to a source of the driving transistor (T13, T53); wherein the driving transistor (T13, T53) has a gate connected to one terminal of the capacitor (C11, C51), and a drain connected to an anode terminal of the organic light emitting diode (31, 59) via the third switching transistor (T16, T56); wherein the compensation transistor (T15, T55) has a drain connected to the gate of the driving transistor (T13, T53), a source connected to the drain of the driving transistor (T13, T53), and a gate to which the scan signal (Gate(n)) is applied; wherein the second switching transistor (T11, T51) has a gate to which the emission signal (Em) is applied, a source to which the power supply voltage (V dd) is applied, and a drain connected to the source of the driving transistor (T13, T53); wherein the third switching transistor (T16, T56) has a gate to which the emission signal (Em) is applied, a source connected to the drain of the driving transistor (T13, T53), and a drain connected to the anode terminal of the organic light emitting diode (31, 59); wherein the power supply voltage (V dd)of a high level is supplied to the other terminal of the capacitor (C11, C51); and wherein the organic light emitting diode has a cathode terminal connected to a power supply voltage (V ss); and wherein a scan signal for turning on the dual gate transistor is applied to the second gate to charge the data signal applied to the data line, and an adaptively controlled scan signal is applied to the second gate to read out a signal from the photosensor from the data line.