Patent ID: 8294700

Claim:
An active matrix type display device, comprising: pixels arranged in matrix, each including a current-driven type light emitting element and a transistor for controlling a current of the current-driven type light emitting element to perform display; horizontal power supply lines arranged in a horizontal direction, for supplying a current to pixels in respective corresponding horizontal lines; and switches for connecting each group of the horizontal power supply lines, the each group including at least one horizontal power supply line, to one of a first power supply line and a second power supply line in a switchable manner, the first power supply line and the second power supply line being disposed outside a pixel region, wherein only the at least one horizontal power supply line in a group to which a pixel to be measured belongs is supplied with power from one of the first power supply line and the second power supply line so as to measure a current of each pixel in the group, and a current flowing into a power source connected to a group to which other pixels than the pixel to be measured belong is measured, to thereby calculate a pixel current based on a difference between the two measured currents.