| 摘要 |
PROBLEM TO BE SOLVED: To provide an inspection method that enables detection of a minute foreign substance present in a deep part inside a transparent material and further an accurate grasp of a shape thereof.SOLUTION: An inspection method for optically inspecting a foreign substance present inside a light-transmitting material according to the present invention comprises: an irradiation step of irradiating a light-transmitting material with irradiation light; a light reception step of receiving emission light that is obtained after the irradiation light is transmitted by the light-transmitting material; and an analysis step of analyzing the received emission light. A light receiving part for receiving the emission light is disposed on light beam axes of the irradiation light, and the received emission light is composed of a direct light component that has been transmitted without being in contact with the foreign substance and a diffraction light component that has been diffracted on an outer periphery of the foreign substance. Analysis of the foreign substance is executed on the basis of information obtained from the direct light component and the diffraction light component. |
