| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a GRIN lens having a large numerical aperture and free from dispersion in the refractive index distribution form at a low cost. SOLUTION: A method for manufacturing the GRIN lens comprises forming a cylindrical wet gel of silicon by laminating layers containing a refractive index imparting metal in different concentrations on the inner peripheral face of a vessel whose inner peripheral face is cylindrical while rotating the vessel so that the concentration of the refractive index imparting metal becomes higher toward inner side, then forming a cylindrical dry gel by drying the cylindrical wet gel, forming a cylindrical glass body by sintering the cylindrical dry gel, forming a columnar GRIN lens preform in which the inner diameter is closed by successively heating the cylindrical glass body from its one end part while rotating the glass body, and heating and drawing the GRIN lens preform into a desired diameter. Thereby, it is possible to impart the desired refractive index distribution without causing dispersion, and to produce the lens with yield of 100% without losing the expensive refractive index imparting metal component by elution. Accordingly, the production cost can be reduced drastically. COPYRIGHT: (C)2005,JPO&NCIPI
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