| 摘要 |
PURPOSE:To improve durability and reproducibility of an interference color by forming plural layers of films having refractive indexes equivalent to predetermined film thickness successively on the surface of transparent synthetic resin made optical parts. CONSTITUTION:An SiO2 layer 31 of refractive index n1=1.46, thickness 900nm, a mixed material layer 32 of Al2O3 and r2O3 of refractive index n2=1.68 and optical film thickness lambda1/4 (lambda1=396nm), a ZrO2 layer 33 of refractive index n3=1.95 and optical film thickness lambda2/2 (lambda2=430nm) and an SiO2 layer of refractive index n4=1.46 and optical film thickness lambda3/4 (lambda3=492nm) are vacuum deposited on a spectacle lens 30 made of diethylene glycol bis (alkali carbonate) of, for example refractive index n0=1.5. These layers are so constituted as to satisfy lambda1<lambda2, n1not equal to n0, n4<n2<n3. This antireflection film has good durability and good reproducibility of an interference color. |
