| 摘要 |
PURPOSE:To obtain a long-sized product having high resolution and superior resistance to environment when an image guide consisting of a core and a clad is produced, by irradiating the clad by a specified method. CONSTITUTION:An image guide 1 is placed in front of a planar radiation source 3, and plural radiation screens 2 such as lead blocks are arranged at proper intervals between the source 3 and the guide 1. The guide 1 is irradiated through a part where the screens 2 are not present. The optical transmission loss of the clad is increased, and the direct light is reduced, so the contrast of an image is enhanced. When the whole guide 1 is irradiated without arranging the screens 2, the transmission loss is so increased that transmission over a long distance can not be carried out. When only both ends of the guide 1 are irradiated, the generation of direct light at the intermediate part of the guide 1 is not prevented. |
