Patent ID: 6734978
Filing Date: 2004-05-11
Classification: G01B

Abstract:
A profile measuring method of calculating, using a phase shift method, a phase value of an interference image formed by a light beam reflected from an object and a light beam reflected from a reference mirror, thereby obtaining an optical path difference from the calculated phase value and obtaining a profile of the object from the optical path difference, comprising:emitting, to the object, two flash light beams, having wavelengths slightly different from each other, with a predetermined interval t1 therebetween; and picking up, using a camera, interference light formed by light beams reflected from the object and a light beam reflected from the reference mirror, while moving the object in a direction, in which the two flash light beams are directed, in units of intervals t2 at which each of the two flash light beams is cyclically emitted, a phase shift amount corresponding to a movement amount of the object at a time being set to a value falling within a range of 2n&pgr;Â±&pgr;/2Â±&pgr;/4, n being an integer not less than 1.