| 摘要 |
PROBLEM TO BE SOLVED: To continuously manufacture a plastic rod lens stabilized in performance and having very small changes of the MTF for a long time. SOLUTION: This manufacturing method has: a 1st step to concentrically arrange three or more kinds of hardenable materials so that the refraction index gradually changes lower from the center to the periphery when hardened to form a hardened strand fiber of three or more layers; a 2nd step to make the above two layers have a continuously changing distributed refraction index by dispersing the above hardenable materials constituting the adjoining two layers at the boundary of the above hardenable strand fiber; and a 3rd step to harden the strand fiber by irradiating it with an ultraviolet ray in two or more levels. The intensity of the ultraviolet ray to irradiate at the 1st level in the above 3rd step is changed from the initial set-up intensity to within the predetermined limits. COPYRIGHT: (C)2006,JPO&NCIPI
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