The area occupied by a photo-sensor element may be reduced and multiple elements may be integrated in a limited area so that the sensor element can have higher output and smaller size. Higher output and miniaturization are achieved by uniting a sensor element using an amorphous semiconductor film (typically an amorphous silicon film) and an output amplifier circuit including a TFT with a semiconductor film having a crystal structure (typically a poly-crystalline silicon film) used as an active layer over a plastic film substrate that can resist the temperature in the process for mounting such as a solder reflow process. A sensor element that can resist bending stress can be obtained.