Patent ID: 6407806
Filing Date: 2002-06-18
Classification: G01B,G01D

Abstract:
An angle compensation method for compensating for an angle of a light-receiving surface of a photodiode disposed in an inclination detection device, said light-receiving surface being divided into four parts by an a-axis and a b-axis disposed perpendicular to each other and receiving light reflected from an object surface that is an X-Y plane, said inclination detection device seeking an inclination of the object surface from changes in an irradiation position of the light reflected on the photodiode light-receiving surface, said method comprising the steps of fixing the light-receiving surface to a rotary stage that can rotate both about a c-axis that passes through an intersection of the a-axis and b-axis and is perpendicular to the a- and b-axes and about a k-axis that is parallel to a Z axis of the object surface; and rotating the light-receiving surface about the c-axis and k-axis so that, when the light-receiving surface is projected onto the object surface, the a-axis aligns with a Y-axis and the b-axis aligns with an X-axis.