Patent ID: 8084743

Claim:
An image pickup device comprising: a flexible substrate; an X-ray sensor arranged on the flexible substrate; and a field effect transistor for reading a signal from the X-ray sensor, wherein: an active layer of the field effect transistor comprises an amorphous oxide of a compound having (a) a composition when in a crystalline state represented by In 2−x M3 x O 3 (Zn 1−y M2 y O) m , wherein M2 is Mg or Ca; M3 is B, Al, Ga or Y; 0≦x≦2; 0≦y≦1; and m is zero or a natural number less than 6, or a mixture of said compounds and (b) an electron carrier concentration of 10 12 /cm 3 or more and less than 10 18 /cm 3 , wherein an electron mobility of the active layer tends to increase with increasing electron carrier concentration and wherein a current between drain and source terminals of the field effect transistor when no gate voltage is applied is less than 10 microamperes.