| 摘要 |
PURPOSE:To separately inspect the internal flaw and surface flaw of a substrate having transparency, by irradiating the substrate with light having a strip-like expansion from the side surface thereof. CONSTITUTION:The laser beam 4 from a laser oscillator 3 is converted to laser beam having a strip like expanse in the direction vertical to the plane of a transparent substrate 1 through a cylindrical lens 2 to be projected on the substrate 1. Further, an X-Y stage 8 is moved in the direction crossing the irradiation direction of the laser beam 4 at a right angle to project the beam 4 on the whole of the substrate 1. When a flaw is present in the propagation path of the beam 4, only the flaw beam scattering by the flaw is emitted from the plane of the substrate 1. The image of this flaw beam is picked up by a TV camera 9 and converted to an image signal TS to be inputted to an image processor 10. The image signal PS obtained by the image processing of the processor 10 is inputted to a monitor apparatus 11 and the flaw image corresponding to the flaw present in the substrate or on the surface thereof is projected on the apparatus 11 to perform the inspection of the flaw. |
