再颁专利
- 专利标题: Objective lens for optical disks having different thicknesses
- 专利标题(中): 具有不同厚度的光盘的物镜
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申请号: US11076588申请日: 2005-03-10
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公开(公告)号: USRE41455E1公开(公告)日: 2010-07-27
- 发明人: Yoshiaki Komma , Sadao Mizuno , Seiji Nishino
- 申请人: Yoshiaki Komma , Sadao Mizuno , Seiji Nishino
- 申请人地址: JP Osaka
- 专利权人: Panasonic Corporation
- 当前专利权人: Panasonic Corporation
- 当前专利权人地址: JP Osaka
- 代理机构: Clark & Brody
- 优先权: JP5-14432 19930201; JP5-193353 19930804
- 主分类号: G02B5/32
- IPC分类号: G02B5/32 ; G02B7/00 ; G02B3/10 ; G02B3/08
摘要:
A compound objective lens is composed of a hologram lens or transmitting a part of incident light without any diffraction to form a beam of transmitted light and diffracting a remaining part of the incident light to form a beam of first-order diffracted light, and an objective lens for converging the transmitted light to form a first converging spot on a front surface of a thin type of first information medium and converging the diffracted light to form a second converging spot on a front surface of a thick type of second information medium. Because the hologram selectively functions as a concave lens for the diffracted light, a curvature of the transmitted light differs from that of the diffracted light. Therefore, even though the first and second information mediums have different thicknesses, the transmitted light incident on rear surface of the first information medium is converged on the its front surface, and the diffracted light incident on a rear surface of the second information medium is converged on the its front surface. That is, the compound objective lens has two focal points.