| 摘要 |
PROBLEM TO BE SOLVED: To accurately perform focusing control and tracking control by integrally molding a diffraction grating to be disposed in an optical path and an optical element having a lens function out of the same material into optical elements. SOLUTION: An integrally molded body 50 of transparent plastic is formed with a fitting surface to be fitted with a laser diode 20, and a surface opposite to an emitting surface of this laser diode 20 is recessed, and its bottom surface is provided with a groove part 50b in a fashion of a large number of fine lines to form a collimator lens. Then, a surface on which a light beam reflected by a recording medium and then reflected by a hald mirror surface 23a of a beam splitter 23 is incident is provided with a concave spherical surface to form a concave lens surface as a 2nd optical surface, and its emitting surface is formed with a cylindrical surface 50d to form a cylindrical lens. An opaque coated layer 51 is provided over the whole surface of the integrally molded body 50 except every optical surface of the integrally molded body and the fitting surface of the beam splitter 23. |
