| 摘要 |
PURPOSE:To control the exposure value in an easy and highly precise way without changing the distribution of luminous intensity, by putting a light shielding matter between a photosensitive material for exposure and a light source to vary the light volume and then moving the light shielding matter on the light source. CONSTITUTION:A light shielding disk 4 is provided between a photosensitive material for exposure and a light source 6 in order to vary the light volume. The disk 4 is turned at such a speed that the blinking of the light due to the slits 8 of the disk 4 has a considerably short cycle compared with the exposure time. Under such conditions, the light is scattered from the light source 6. It is possible to vary the volume of the light reaching the printing surface by changing the area ratio between the disk 4 and the slits 8. As a result, the exposure value can be controlled in an easy and highly precise way without varying the distribution of luminous intensity. |
