| 摘要 |
PURPOSE:To measure the straightness or flatness of a surface to be measured by arranging a reference plane facing the surface being measured and measuring the distance distribution between both surfaces with a laser length measuring device to remove non-parallel portions. CONSTITUTION:A reference plane 11 such as optical flat and the surface 12 to be measured of an object are held almost parallel and a guide rail 21 is moved vertically to the surface of a paper while a table 22 moved along the guide rail 21 to shift an interferometer 27 along the reference plane 11 and the surface 12 being measured. In this manner, the distribution of distance l between the surface 12 being measured and the reference plane 11 is measured. The space (s) between parallel planes putting a curve C at the right angle to the section having the surface 12 being measured from the curve C about the section is determined. This removes non parallel portions between the reference plane 11 and the surface 12 being measured which makes the space (s) to be determined as the straightness or flatness. |
