| 摘要 |
<p>PURPOSE:To certainly discriminate a pattern by setting the optimum polarization angle even when the polarization angle of scattering light is changed by the effect of a pattern shape. CONSTITUTION:When holizontal polarized laser L0 is emitted in the direction shown by an arrow, scattering beam L2 wherein both horizontal and vertical polarized beams are mixed is generated from foreign matter 2 and scattering light L1 mainly composed of vertical polarized beam is generated from a pattern 1. Both scattering beams are passed through polarizing filters 3a, 3b to be detected by detectors 4a, 4b and the foreign matter 2 or the pattern 1 is discriminated on the basis of the detection signals l1, l2 from the detectors by a pattern discrimination circuit 5 and only the signal from the foreign matter 2 is outputted and the size of the foreign matter is operated by an operational processing part 6. By this method, a pattern can be certainly discriminated.</p> |
