The present invention provides a single transformer full-duplex digital isolator whereby two digital data streams may simultaneously be transmitted and received in opposite directions of propagation through a single transformer. The methods include forming a multilayer dielectric layer including metal atoms and silicon atoms on a semiconductor substrate. When the user specifies a point on the panel screen, a real size of the object at the specified point is obtained in accordance with the 3D positional information. Each coding unit includes a light converging portion and a light diverging portion.