Patent ID: 8547307

Claim:
A display device, comprising: a luminescence element including a first electrode and a second electrode; a first power line electrically connected to the first electrode; a second power line electrically connected to the second electrode; a capacitor including a third electrode and a fourth electrode, the capacitor holding a voltage; a driving transistor between the first electrode and the first power line that causes the luminescence element to emit light by passing a current between the first power line and the second power line, the current corresponding to the voltage held by the capacitor; a data line through which a signal voltage is supplied to one of the third electrode and the fourth electrode; a data-line driver that supplies the signal voltage to the data line; a first switch between the data line and the one of the third electrode and the fourth electrode for switchedly supplying the capacitor with the signal voltage; a voltage detector connected to the data line for detecting a luminescence voltage applied to the luminescence element; a second switch between the data line and the first electrode; a controller that: causes the capacitor to hold a first voltage corresponding to a first signal voltage supplied through the data line by switching on the first switch, the driving transistor to pass, between the first power line and the second power line, a first current corresponding to the first voltage held by the capacitor, and the voltage detector to detect a first luminescence voltage applied to the luminescence element via the data line by switching off the first switch, switching on the second switch, and making a connection between the data-line driver and the data line open while the luminescence element emits the light; and causes the capacitor to hold a second voltage corresponding to a second signal voltage which is different in value from the first signal voltage and is supplied through the data line by switching on the first switch, the driving transistor to pass, between the first power line and the second power line, a second current corresponding to the second voltage held by the capacitor, and the voltage detector to detect a second luminescence voltage applied to the luminescence element via the data line by switching off the first switch and switching on the second switch while the luminescence element emits the light; and a determiner that determines a first drain current and a second drain current of the driving transistor based on the first luminescence voltage and the second luminescence voltage detected by the voltage detector, respectively, and calculates a gain coefficient and a threshold voltage of the driving transistor based on the first luminescence voltage, the second luminescence voltage, the first drain current, and the second drain current.