Patent ID: 7417676

Claim:
A method of driving a device comprising a pixel portion having a plurality of pixels each comprising a photoelectric conversion element and a display element, comprising the steps of: reading a first calibration sheet to obtain a first image signal of each of the plurality of pixels by using the photoelectric conversion element; reading a second calibration sheet to obtain a second image signal of each of the plurality of pixels by using the photoelectric conversion element; calculating a first difference between the first and second image signals of each of the plurality of pixels; obtaining at least a value selected from a modal value, an average value and a maximum value of the first difference of each of the plurality of pixels; determining whether each of the plurality of pixels is a defective pixel by obtaining a second difference between the first difference of each of the plurality of pixels and the value of selected from a modal value, an average value and a maximum value of the first difference of the plurality of pixels; and displaying a third image by using the display element, wherein the step of reading the first calibration sheet, the step of reading the second calibration sheet, and the step of displaying the third image are performed using the pixel portion.