| 摘要 |
PURPOSE:To simplify and miniaturize the mechanism of a device by providing a mechanism which automatically detects the existence of a slide and an automatic focusing mechanism to a slide moving mechanism. CONSTITUTION:The slide projection device is mounted to a copying machine and it is the device for taking a copy from the slide. A light emitting element 16 is lighted by making a holder frame 11 descend and light reflected on the slide 10 is condensed to two-split photodetectors 18a and 18b. Then, since the reflected light does not occur when the slide is not inserted, it is automatically detected that the slide is not inserted. Next, the guide pins 9a and 9b of a slide holder 9 are moved along the long holes 11a and 11b of the frame 11, and the center of the reflected light coincides with the centers of the elements 18a and 18b when the slide 10 arrives at a focusing position. Then, outputs from the elements 18a and 18b are equalized. At this time, since the distance between the slide 10 and the principal point H of an image forming lens 7 is adjusted so that it becomes a target focal distance LO, focusing is automatically executed. |
