| 摘要 |
PURPOSE:To prepare an optical glass part capable of changing the refractive index in the radial direction, by adding a dopant capable of changing the refractive index to an aqueous solution containing silicic acid, gelatinizing the resultant mixture, and eluting the dopant from the resultant porous gelatinized material by the leaching method. CONSTITUTION:A given amount of a nitrate, sulfite, carbonate, etc. of Tl, Cs, Rb, etc. convertible into an oxide dopant capable of changing the refractive index is added to an acidic or alkaline aqueous solution containing silicic acid in a cylindrical container. The resultant mixture is then neutralized with an alkali or acid to adjust the pH to 4-6, gelatinize the contained silicic acid and form a gelatinized material containing a cylindrical porous silica as a skeleton. The formed cylindrical material is then leached with a solvent, e.g. water, alcohol or ketone, to elute ions of the Tl, Cs, Rb, etc. in the dopant composition suitably and give a porous gelatinized siliceous material in which the refractive index is changed in the radial direction. The solvent, etc. is then removed from the material, and the micropores are eliminated to form a transparent rod-like lens. |
