1. A method of compensating for unevenness and voltage drop in an EL display, comprising: (a) providing the EL display having a substrate; (b) forming on the substrate a plurality of pixels arranged in a matrix of horizontal lines and vertical lines, each pixel having an organic EL element for display use and a TFT for controlling current supply to the organic EL element; (c) forming on the substrate a plurality of power supply lines corresponding to the horizontal lines of the matrix, each supplying power to pixels of the corresponding horizontal line; (d) forming on the substrate a plurality of independent wiring terminals, each connected to one or more of the plurality of power supply lines; (e) prior to displaying an image, selecting a pixel; (f) providing a first image signal to the EL display to turn on the selected pixel; (g) measuring a first pixel current; (h) providing a second image signal to the EL display to turn off the selected pixel; (i) measuring a second pixel current; (j) calculating a difference between the first pixel current and the second pixel current, calculating correction data based on the difference, and storing the correction data; (k) repeating steps (e) through (j) for an unselected pixel until all of the pixels have been selected; (l) receiving for each of the plurality of pixels a respective third image signal corresponding to an image to be displayed; (m) for each horizontal line, calculating a respective voltage drop of each pixel in the horizontal line, based on the respective third image signals for the pixels in the horizontal line, and adding the respective voltage drops to the respective third image signals to produce a plurality of respective first compensation signals; (n) correcting the first compensation signals for unevenness using the stored correction data to produce second compensation signals; and (o) providing the second compensation signals to the EL display to display the image to be displayed while compensating for unevenness and voltage drop in the EL display.