Patent ID: 8581257

Claim:
A circuit board comprising: an insulating substrate; and a plurality of transistor elements provided on the insulating substrate, the plurality of transistor elements being provided for (i) respective pixels arranged in a matrix manner or (ii) respective pixels in a group of a predetermined number of the pixels, at least one of the plurality of transistor elements being a first thin film transistor element having a first channel layer formed by an oxide semiconductor, at least another one of the plurality of transistor elements being a second thin film transistor element having a second channel layer formed by (i) an amorphous silicon semiconductor, (ii) a microcrystalline silicon semiconductor, or (iii) a semiconductor in which the amorphous silicon semiconductor and the microcrystalline silicon semiconductor are stacked, each of the first thin film transistor element and the second thin film transistor element being a bottom-gate transistor, a first gate insulating film composed mainly of SiO 2 being provided between the first channel layer and a first gate electrode of the first thin film transistor element, (i) a second gate insulating film which is composed mainly of SiN x and (ii) a third gate insulating film which is composed mainly of SiO 2 being provided, between the second channel layer and a second gate electrode of the second thin film transistor element, so as to be stacked in this order from a second channel layer side, the first gate insulating film and the third gate insulating film being formed as a single film, the first thin film transistor element and the second thin film transistor element constituting an optical sensor circuit, the first thin film transistor element serving as a sensor output section of the optical sensor circuit, and the second thin film transistor element serving as an optical sensor element of the optical sensor circuit.