| 摘要 |
PURPOSE:To obtain the plastic light transmission body which can maintain good characteristics over a long period of time by specifying the content of the low mol. wt. material of <=2,000mol.wt. existing in the light transmission body. CONSTITUTION:The low mol. wt. material of <=2,000mol.wt. diffuses and transfers in the light transmission body with lapse of time and induces a change in the characteristics of the light transmission body with age if the low mol. wt. material exists in the distributed index type plastic light transmission body. The content of the low mol. wt. material of <=2,000mol.wt. is, thereupon, confined to <=3wt.%. The light transmission body which can hold sufficient resolving power even after long-term use is obtd. in this way. |
