Patent ID: 9080865
Filing Date: 2015-07-14
Classification: G01B

Abstract:
1. An orthogonality compensation method for length measurement device, comprising the following steps: (1) providing a measuring platform and a plurality of alignment marks, wherein the measuring platform comprises a fixed chassis, a rectangular measuring table mounted on the chassis and thus fixed, an inspection microscope arranged above the measuring table, a laser device mounted on the chassis and coupled to the inspection microscope, first and second guide rails that are mounted on the measuring table and are respectively located at two opposite sides of the measuring table so that a top surface of the measuring table is located between the first and second guide rails, and a cross bar movably mounted on and extending between the first and second guide rails to be located above the top surface of the measuring table, the inspection microscope being slidably mounted on the cross bar and thus located above the top surface of the measuring table; (2) mounting the alignment marks on the top surface of the measuring table and recording the coordinates of the alignment marks with respect to the coordinate system of the measuring table to provide reference coordinates; (3) using the inspection microscope through movement of the cross bar along the first and second guide rails and sliding motion of the inspection microscope along the cross bar to read actual coordinates of the alignment marks with respect to the coordinate system of the measuring table and comparing the actual coordinates with the reference coordinates; and (4) carrying out correction of coordinates if differences exist between the actual coordinates and the reference coordinates, so as to directly correct the actual coordinates to be equal to the reference coordinates through compensation with the differences without movement of the measuring table.