FOCUSING METHOD, MEASUREMENT METHOD, PRINCIPAL POINT DETECTION METHOD, FOCUSING DEVICE, MEASUREMENT DEVICE AND PRINCIPAL POINT DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a focusing method that can focus on a sample even when the sample is clear and transparent and a surface shape of the sample is smooth.SOLUTION: A focusing method has: a step of preparing a microscope; a step of mounting a sample having a surface shape curved to the microscope; and a prescribed processing step. The prescribed step has the steps of: receiving light emitted from an observation optical system; obtaining an amount of light on the basis of light from a prescribed area of the received light; calculating a difference between the amount of light in the prescribed area and a reference amount of light or a rate therebetween; comparing the a calculation result with a threshold; and changing an interval between the sample and the observation optical system. In the preparation step, one part area of illumination light is shaded or dimmed, and the prescribed area is one area of the sample, and when the calculation result is less than the threshold, the prescribed processing step is ended.