Patent ID: 7209242

Claim:
A non-contact surface configuration measuring apparatus for measuring a surface configuration of an object, the apparatus comprising: a position detector configured to detect a position of a surface of the object, the position detector being fixed relative to the apparatus, and configured to direct a laser beam passing through an optical path around an optical axis of an objective lens, via the objective lens to the object, and form an image of a laser beam being reflected from a surface of the object through the objective lens onto an image sensor, to detect a position of the surface in a direction of the optical axis; and a scanner configured to support the object and move the object in at least one of a first direction and a second direction, the first and second directions being oriented in an X-Y plane defined by an X-axis and a Y-axis extending perpendicularly to one another, the X-Y plane perpendicularly intersecting the optical axis, the scanner being fixed relative to the apparatus and being able to rotate the object about a third imaginary axis extending parallel to the Y-axis which perpendicularly intersects the optical axis; wherein, a range of angles in which a normal vector to the surface of the object forms with the optical axis is set for the position detector to detect the position of the surface with a predetermined position accuracy; a first continuous area in which a normal vector to the object surface falls within the range of angles is defined on the surface of the object fixed on the scanner; a second continuous area of the object surface overlapping the first area at an edge thereof is defined; first position information on the first area is obtained; and second position information on the second area is obtained with the object rotated at a predetermined angle about the third imaginary axis by the scanner so that a normal vector to the surface within the second area falls within the range of angles; and the first position information is overlapped with the second position information such that respective position information pieces on the overlap surface of the object substantially agree.