| 摘要 |
PURPOSE:To decide on whether a painted or lacquer-coated surface is acceptable by utilizing the scattering and polarization solution of an incident polarized beam. CONSTITUTION:When a polarized beam 11 is caused to strike a coating 10, part of it is reflected by a top surface and the remaining light 16 is transmitted in the coating 10 to have mutual action with pigment particles 20. Pigment particles 20 exert great influence on the light beam by absorbing light in a specific wavelength band. Further, the important point is that pigment particles scatter the incident light and light energy is absorbed and then radiated from each center of scattering as a spherical wave. As far as the beam makes a scan in an excellent area of a container cover, unpolarized beams having relatively uniform intensity are scattered and detected. When the incident scanning beam strikes an irregular part, a triffle light or light consisting of polarized component nearly on the whole is reflected. Abrupt variation in the level of an output signal from a video camera due to a scratch, stain, etc., of the container cover shows a defective container cover.
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