| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a defect inspection method that facilitates detection of a defect by improving a contrast of an image of a phase object such as a fine irregularity defect and the like on a surface of an optical member even when intensity unevenness of illumination light or noise such as an image of a foreign object adhered to an inspected object and the like is included.SOLUTION: A defect inspection method for irradiating an inspected object 4 with light to be emitted from a light source 1, and performing a defect inspection of the inspected object 4 on the basis of light transmitting the inspected object 4 has the steps of: acquiring at least one or more images when an image formation position 9 of the inspected object 4 is located on an inspected object 4 side with respect to a light-reception surface 8 receiving light via an image formation optical system 5; acquiring at least one or more images when the image formation position 9 of the inspected object 4 is located on an opposite side of the inspected object 4 with respect to the light-reception surface 8 receiving the light via the image formation optical system 5; and performing a computation process of a difference between the images acquired in the two steps described in the above.</p> |
