| 摘要 |
PROBLEM TO BE SOLVED: To make a refractive index distribution contant in a longitudinal direction and radial direction as well. SOLUTION: A plastic rod 1 is rotated around the axis of a horizontally arranged rod while a part of the outer peripheral surface of the rod is brought into contact with a liquid monomer 2 for forming the plastic of the refractive index lower than the refractive index of the plastic. The rod is then irradiated with radiation from above the rod to polymerize the monomer, by which a first polymer layer is grown to the prescribed outside diameter. The rod is rotated while the outer peripheral surface is partly brought into contact with the monomer of the refractive index lower than the refractive index of the previous liquid monomer 2 and the polymn. is continued under the irradiation with the radiation, by which the second polymer layer is grown to the prescribed outside diameter and thereafter, the polymer layers are formed up to the n-th polymer layer by the same procedures. |
