| 摘要 |
PURPOSE:To judge the position and size of a foreign matter defect adhering to an object to be inspected and to which the foreign matter adheres, the top or bottom surface of the object to be inspected with ease by irradiating parts to be irradiated almost the same of the object to the inspected with two luminous fluxes different in wavelength. CONSTITUTION:Parts to be irradiated of an object to be inspected are irradiated with two luminous fluxes 21 and 22 which are distributed in wavelength areas different from each other while having light transmittances different with respect to the object to be inspected from light sources 6 and 7. Photo detectors 16 and 17 receive scattered light 12 generated from the parts to be irradiated with the irradiation of the two luminous fluxes 21 and 22 respectively as scattered light 23 and 24 being separated in wavelength through an optical system and then, output photoelectric signals corresponding to the scattered light 23 and 24 individually. Moreover, based on sizes of two photoelectric signals, a judging section judges to which a foreign matter defect adheres, a luminous flux incident surface side or another surface side. |
