| 摘要 |
PROBLEM TO BE SOLVED: To provide a measurement device which is beneficial for measuring the position of a surface to be inspected with high accuracy.SOLUTION: A measurement device 20 for measuring the position of a surface to be inspected includes: a light source 3 having an emission port 3a for emitting light 4; a detection part 9 for detecting the angle of ejection of light to be emitted from the ejection port 3a; and a processing part for calculating optical path length between the ejection port 3a and the surface to be detected by using light emitted from the emission port 3a, and reflected on the surface to be detected and light emitted from the ejection port 3a, and reflected on a reference surface, and for determining the position of the surface to be detected on the basis of the optical path length. The processing part calculates the path length of the light from the ejection port 3a to the surface to be detected on the basis of interference between the light reflected on the surface to be detected and the light reflected on the reference surface, and determines a correction value for correcting the error of the path length which may be generated due to the angle of ejection by using the inclination of the surface to be detected to the reference surface and the path length and the angle of ejection, and calculates the optical path length by correcting the path length with the correction value. |
