| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain an object optics for an optical recording medium which can be used commonly to three optical recording mediums having different specifications of a numerical aperture of a usage optical system, a wavelength of a usage beam, a thickness of a substrate and the like, can successful maintain optical performance and can be made compact and inexpensive and to provide an optical pickup apparatus using the same. <P>SOLUTION: An objective lens is formed by integrally forming a first lens body 18 having a diffraction optical surface 18a formed on a light source side and a second lens body 19 having positive refractive force sequentially from the light source side. The second lens body 19 is a biconvex lens and both a light source side surface and an optical recording medium side surface are rotationally symmetric non-spherical surfaces. Each beam whose luminous flux is limited to the usage beam is successfully converged in recording areas 10a, 10b and 10c respectively of a BD9a, a DVD9b and a CD9c. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
