Patent ID: 8530246

Claim:
A method for controlling a threshold voltage of a semiconductor element comprised of a semiconductor in a semiconductor device comprised of the semiconductor element and an electroluminescent element driven by the semiconductor element, comprising the steps of: measuring a threshold voltage of the semiconductor element or a characteristic value serving as an index for the threshold voltage; determining an irradiation intensity, an irradiation time or a wavelength of light with which the semiconductor is irradiated by the measured threshold voltage or characteristic value; and irradiating the semiconductor with a light, the light having a longer wavelength than a wavelength of an absorption edge of the semiconductor, wherein the semiconductor device includes a plurality of semiconductor elements, the semiconductor device is equipped with one light source for collectively irradiating the light onto the plurality of semiconductor elements when the plurality of semiconductor elements are close to one another, and the threshold voltage of the plurality of semiconductor elements is simultaneously changed by the one light source.