| 摘要 |
PURPOSE:To obtain optical parts having a durable coating film which suppresses light reflection on a plastic surface and is stable in optical characteristics and free from peeling, etc., by forming an MgF2 layer and Al2O3 to specific optical thicknesses in sequence from the top layer and by using an SiO layer having a specific film thickness as the lowermost layer. CONSTITUTION:On plastics-made substrate B, SiO is formed to <=20mum film thickness by a resistance heating method, etc., to form the 3rd layer III having adhesive strength to plastics. On layer III, the 2nd layer II of Al2O3 is vapor-deposited by an ion plating method to <0.50lambda0 as design wavelength lambda0. Finally MgF2 is formed as the 1st layer I by the ion plating method to 0.25-0.30lambda0 thickness. Thus, a durable lens, etc., with a small secular change in optical characteristics can be obtained which has suppressed reflection upon air layer A with the 3rd layer having 1.620 refractive index, the 2nd layer having 1.620 and the 1st layer having 1.385 respectively to the substrate having 1.49. |
