| 摘要 |
PURPOSE:To accurately detect even a pattern which has a high light reflection factor by arranging a linear light shield body newly at a position corresponding to a black line on the pattern to be detected. CONSTITUTION:Illumination light L which is emitted by a linear light source 2, passed through a 1st linear light shield body 3, and transmitted through a lens 4 for image formation contains light leaking from a light area. Then, the 2nd linear light shield body 9 is provided between the lens 4 for line image formation and a printed board 1 at the position corresponding to the black line B on the board 1 to remove the leaking light, thereby forming a dark black line B which contains almost no leaking light on the pattern to be detected. Therefore, even if the pattern to be detected has a part whose light reflection factor is extremely high, leaking light which is reflected from in the black line B is a little and the detected pattern is every accurate. |
