MANUFACTURE OF PLASTIC OPTICAL TRANSMISSION BODY

PURPOSE:To form easily an optical waveguide having an arbitrary pattern and to obtain an optical transmission body having superior optical transmission power with high productivity by using a photosensitive laminate so as to provide a difference in refractive index. CONSTITUTION:A photosensitive laminate is composed of a resist layer 2 and a support 1 having a lower refractive index than the layer 2 or a support 1' having a surface layer having a lower refractive index than the layer 2. A photomask for transfer is placed over the surface of the laminate at a distance enough for image transfer, and the layer 2 is exposed to active light through the mask to cause a curing reaction in the layer 2. The uncured part of the layer 2 is removed with an aqueous alkali soln. for development to form a resist image on the support. A soln. of a polymer having a lower refractive index than the cured resist layer is then applied so as to perfectly cover the resist layer, and it is dried to form a layer having a lower refractive index than the inner cured resist on the surface of the resist.