公开(公告)号：US20080062827A1

公开(公告)日：2008-03-13

申请号：US11850536

申请日：2007-09-05

申请人： Mayumi TSUKAMOTO ,  Masaharu FUKAKUSA ,  Hiroshi SATO ,  Eizo ONO

发明人： Mayumi TSUKAMOTO ,  Masaharu FUKAKUSA ,  Hiroshi SATO ,  Eizo ONO

IPC分类号： G11B7/00

CPC分类号： G11B7/1378 ,  G11B7/0909 ,  G11B2007/0006 ,  G11B2007/13722

摘要： An optical pickup device includes:a laser source for emitting, to an optical disk, a laser beam having a wavelength λ1 and a laser beam having a wavelength λ2, which is longer than the wavelength λ1; a light receiver, for receiving laser beams that are reflected by the optical disk;a beam splitter, for directing, to the light receiver, the laser beams reflected by the optical disk; andan astigmatism generation element, located between the beam splitter and the light receiver, for generating the laser beams to be used for focusing control, by designating as the front of the light receiver a focal point on one of the intersecting cross sections that include the light axes of the laser beams, and by designating as the rear of the light receiver, a focal point on the other cross section,wherein the astigmatism generation element is an optical element, which is like a Fresnel lens, whose step depth is substantially a natural number times either the wavelength λ1 or the wavelength λ2.

摘要翻译： 一种光学拾取装置，包括：激光源，用于向光盘发射波长λ1的激光束和比波长λ1长的波长λ2的激光束; 光接收器，用于接收由光盘反射的激光束; 分束器，用于将由光盘反射的激光束引导到光接收器; 以及位于分束器和光接收器之间的用于产生用于聚焦控制的激光束的像散生成元件，通过将光接收器的前部指定为包括 激光束的光轴，并且通过将光接收器的后部指定为另一横截面上的焦点，其中像散生成元件是像菲涅耳透镜的光学元件，其阶梯深度基本上是 自然数为波长λ1或波长λ2。