| 摘要 |
PURPOSE:To obviate the influence of a temp. change, the generation of the distortion and face change of a lens and the change of the optical performance thereof by decreasing the difference in the coeffts. of linear expansion between the lens and lens barrel material. CONSTITUTION:Various optical performances (refractive index, Abbe number, etc.) of the lens vary with materials and the coefft. of expansion thereof changes from 55X10<-7> to 110X10<-7>. The lens barrel for holding the lens has preferably the coefft. of expansion equal to or approximate to the coefft. of expansion of the lens in order to obviate the deformation and positional change of the lens owing to a temp. change. The lens barrel 2 is thereupon manufactured by using zirconium oxide. The zirconium oxide which consists essentially of, respectively by wt%, 87-99.9% zirconia (ZrO2), 0-0.6% silicon oxide (SiO2) and 0-12% yttrium oxide (Y3O2) and has 45X10<-7>-110X10<-7> coefft. of expansion is used. |
