| 摘要 |
PURPOSE:To detect surely a mark and to prevent mis-retrieval regardless of the recording position of the mark, by lighting the mark recorded at a side ridge of picture part by the light from a light source through a prism. CONSTITUTION:An optical member made of a wedge-shaped prism 25 is arranged between a condenser lens 15 and a glass plate 16. The prism 25 is placed under a mark detector 21 and has a plane 252 in parallel with a film plane. In feeding the film, the mark of the film is moved between the mark detector 21 and the prism 25. A light (a) through the condenser lens 15 is made incident from the lower face of the prism 25, and the direction of light is changed by being refracted in the prism and irradiated almost vertically from the plane 251 at the upper end. The mark is lighted by this irraditated light (b) and the light transmitting the film is made incident vertically to the photo detecting plane of the mark detector 21. |
