PURPOSE: To provide a pinhole inspection device ensuring the capability of accurately detecting the small diameter pinhole of a sheet having high light transmittance, while utilizing the features of an image sensor system where a solid image pickup element is used in a light receiving section.
CONSTITUTION: In a pinhole inspection device having an image sensor system where an illuminant 1 is laid at one side of a sheet 4 as a measurement object and a light receiving section 6 comprising a solid image pickup element is laid at the other side, a polarizing plate 3 is provided between the sheet 4 and the illuminant 1. Also, another polarizing plate 5 is provided between the sheet 4 and the light receiving section 6. In this case, dislocation between the polarizing planes of the plates 3 and 5 as a pair is kept at 20 degrees or less.
OKUMURA YOSHIHARU
ANDO KATSUTOSHI
| JPS5039591A | 1975-04-11 | |||
| JPS63163152A | 1988-07-06 | |||
| JPH02107951A | 1990-04-19 | |||
| JPS4642151B1 |