Patent ID: 7933665

Claim:
A method for automatically teaching a reference position which is a reference of a position of a disc-like object in a reference co-ordinate system including a position of a handling device to a handling device of the disc-like object, the disc-like object having no substantial concave or convex portions along a peripheral rim, the method comprising: a step of determining a center position of a disc-like object with a known radius which was situated at a fixed place being the reference position in the reference co-ordinate system; and a step of memorizing the position of the fixed place in the reference co-ordinate system which was determined by calculation based on the center position in the handling device as the reference position, wherein the step of determining the center position of the disc-like object comprises: a step of relatively moving a detection means against the disc-like object and making one locus of the detection means cross against a circumference of the disc-like object, a step of determining positions of two intersections by the crossing in the reference co-ordinate system, and a step of calculating the center position using a specific point on a perpendicular bisector of a section of a line combining the two intersections, the two intersections and the radius of the disc-like object.