| 摘要 |
PURPOSE:To obtain a refraction distribution type volume lens which never causes even a fine flicker, by forming a solid solution of titanium dioxide on quartz glass. CONSTITUTION:A glass base material for a volume lens is manufactured by using a complex torch. In the figure, a blow-off opening blows off SiCl4 and TiCl4, a blow-off opening 32 SiCl4, a blow-off opening 33 inert gas, and a blow-off opening 34 H2 and O2 respectively, thereby depositing a porous glass base material having density distribution of TiO2 by flame decomposition. The base material is raised according growth and heated up to 1,500-1,600 deg.C to be made transparent by removing bubbles. Thus, the volume lens is obtained which has the distribution that the refractive index is 1.474 at the highest density point of center TiO2 and decreases in the radius direction. A flicker of the refractive index in the center of the lens is <=0.0002 and an image has no distortion. Further, adding fine P2O5 lowers the temperature of the bubble removal. |
