There are provided a multilayer disc manufacturing apparatus and method, capable of computing a rotational eccentricity of a disc with no contact with the disc and a high accuracy, and producing the disc with lower costs without having to rotate the disc or perform any complicated operations. Each of the sensors are operable to detect at least the presence of a leading edge of a document conveying in close proximity to each sensor. Electrical interconnects coupled to the sensors, circuits, transducers, andor MEMS devices extend other ones of the plurality of substrates. The valve also includes a second moveable poppet piece compressionally biased in a position to seal the fluid discharge port or ports in the first moveable poppet piece. The connecting part extends from the comb-shaped part beyond the other side of the gate electrode.