| 摘要 |
PURPOSE:To obtain plastic optical parts applied with multicoating having superior adhesion and transparency characteristics by forming a first layer comprising SiO2, a second layer comprising SiO, and third layer comprising MgF2 having each specified thickness depending on the design wave length in seriation from a plastic substrate side. CONSTITUTION:A reflection preventing film 2 comprising SiO2 as a first layer, a reflection-preventing film 3 comprising SiO as a second layer, and a reflection- preventing film 4 comprising MgF2 as a third layer are coated on a plastic substrate 1 comprising acrylic lens, polycarbonate lens, etc. Each reflection-preventing film 3-5 is formed in seriation by the conventional vapor deposition process using electron beam heating, and the optical film thickness of each reflection- preventing film is regulated to lambda0/2, lambda0/4, and lambda0/4 by setting the design wavelength as lambda0. Since a material having a low melting point is used for the multi- coating, there is almost no temperature rise in the vapor depostion cell during vapor deposition, and the coating is executed at almost room temp. Accordingly, generation of internal stress is quite little. |
