| 摘要 |
PURPOSE:To improve the adhesive property to the lens, refractive index, durability, etc., by successively providing two layers of a CeF3 layer and MgF2 layer in combination onto a plastic base material. CONSTITUTION:The CeF3 layer and the MgF2 layer are successively provided on the plastic base material. The product of the refractive index (n) and film thickness (d:nm) of the thin film of the CeF3 which is the 1st layer is required to be in an nd=17 to 196 range. The reason for confining nd as a min. limit 17 lies in that the thin film of the CeF3 is required to be 10nm thick in order to maximize the transmittance at 400nm wavelength of light. The reason for confining nd to a max. limit 196 lies in that the thin film of the CeF3 is required to be 119nm thick in order to maximize the transmittance at 2000nm wavelength of light. The product of the refractive index (n) and film thickness (d:nm) of the thin film of the MgF2 which is the 2nd layer is required to be within an nd=75 to 500nm. The plastic lens having the antireflection film which is excellent in the optical characteristics, adhesive property and durability, etc., is obtd. in this way. |
