| 摘要 |
PURPOSE:To form easily a refractive index distribution by swelling a transparent polymer to a specified volume, immersing it in a diluting liq. contg. a low molecular compound which produces a polymer having a lower refractive index than said polymer, and by causing diffusion and reaction under conditions which keep a specified degree of swelling. CONSTITUTION:A columnar polymer having epoxy groups is swollen to a volume satisfying equation I by immersion in a swelling liq. such as methanol. The polymer is immersed in a diluting liq. contg. a low molecular compound such as heptafluorobutyric acid which has reactivity with epoxy groups and produces a polymer having a lower refractive index than said polymer when it reacts with epoxy groups, and the low molecular compound is diffused in the polymer and reacted with epoxy groups under conditions which keep a degree of swelling represented by equation II. The reaction product is dried. The surface of the resulting polymer has a low refractive index, and the index increases continuously toward the center, so a refractive index distribution is formed. Since the polymer has superior image transmitting characteristics, it can be used as a material for a lens for a copying machine, an optical fiber coupling element, a rod lens, etc. |
