| 摘要 |
PURPOSE:To obtain a large-sized refractive index distribution type lens high in purity at low cost by depositing a dopant on a specified porous material and partially eluting this dopant and thereafter calcining this porous material. CONSTITUTION:A refractive index adjustor (dopant) is deposited to the insides of narrow holes by immersing the following porous material into a soln. contg. the dopant. The dopant is partially eluted by furthermore immersing this porous material into dopant soluble liquid and after causing the dopant concn. distribution (refractive index distribution) in the inside of the porous material, it is sintered to obtain a refractive index distribution type lens. The above-mentioned porous material to be used is the porous material obtained by a sol-gel process wherein metallic alkoxide is used as an essential raw material. As the dopant to be used, CsNO3, Pb(NO3)2, TlNO3 and Tl2SO4, etc., are shown. |
