| 摘要 |
PURPOSE:To easily detect variation in illuminance due to surface unevenness or strain in a sample, and to decide on whether the sample is normal or not by detecting the reflected light of parallel luminous flux illuminating the sample and finding an illuminance distribution on the sample, and comparig it with a reference value. CONSTITUTION:A sample 1 on a sample base 10 is irradiated with parallel luminous flux from a light source 2 through a lens 9, and its reflected light is detected through a lens 11 and a photoelectric conversion part 12. If the sample 1 has uneven parts 13-15, those uneven parts serve as a concave mirror and convex mirror to scatter the illumination light. Then, a signal having an illuminance distribution corresponding to the uneven parts 13-15 is detected. The mean value of the entire luminous flux is calculated and multiplied by a constant to find an upper-side and a lower-side reference illuminance value, thereby decidig on whether the sample is normal or not from the number of light and dark parts and area corresponging to said illuminance. Further, a reference sample having a completely specular surface is arranged near the sample 1 to use the reflected light as the mean value. |
