| 摘要 |
PURPOSE:To improve reflection efficiency even to an inspection wavelength for optical axis adjustment while maintaining the transmission efficiency of the use wavelength of the optical head and to facilitate production by providing the optical head device with wavelength selection films so as to uniformly cover the lens face and peripheral edge of an objective lens. CONSTITUTION:The objective lens 1 for the optical head device consists of a molded lens which has the lens faces 2 consisting of biconvex faces in its central part and is integrally formed with the frame-shaped peripheral edge 3 at its peripheral edge. CaFK (low dispersion glass) is used as a lens base plate and the wavelength selection films 4 are formed so as to cover the one face of the objective lens. The films 4 are formed of vapor deposited two-layered films consisting of a first film layer 7 and a second film layer 5. The film layer 7 of the films 4 consists of an Al2O3 and the film layer 5 of ZrO2. The film layer 7 consists of SiO2 and the film layer 5 of TiO2. |
