| 摘要 |
<p>[Object] In the manufacture of a GRIN lens using a sol-gel process, foaming during wire-drawing isi prevented and wire-drawing operation is facilitated so that the yield is improved. [Solving Means] A step of forming a wet gel from an alcohol solution containing, as main components, a silicon alkoxide, a dopant alkoxide, and an aluminum alkoxide; a step of dissolving by leaching the dopant and aluminum away from an outer peripheral surface of the wet gel to provide a refractive index distribution; a step of forming a dry gel by drying the wet gel; a step of forming a glass preform by firing the dry gel; and a step of wire-drawing the perform are provided. In the step of leaching, most aluminum dissolves from the wet gel, thereby increasing the porosity of the dry gel and preventing cracking during sintering and foaming during wire-drawing.</p> |
