Invention Grant
- Patent Title: Coupling lens and optical pickup device
- Patent Title (中): 耦合透镜和光学拾取装置
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Application No.: US11984803Application Date: 2007-11-21
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Publication No.: US07801010B2Publication Date: 2010-09-21
- Inventor: Koji Maezawa , Aya Morishima , Mitsuhiro Miyauchi
- Applicant: Koji Maezawa , Aya Morishima , Mitsuhiro Miyauchi
- Applicant Address: JP Ibaraki-shi
- Assignee: Hitachi Maxell, Ltd.
- Current Assignee: Hitachi Maxell, Ltd.
- Current Assignee Address: JP Ibaraki-shi
- Agency: Oliff & Berridge, PLC
- Priority: JP2006-316170 20061122; JP2006-329874 20061206
- Main IPC: G11B7/135
- IPC: G11B7/135

Abstract:
A coupling lens for chromatic aberration correction is placed between a light source and an objective lens for focusing light beams with a plurality of wavelengths on an information recording surface of an optical recording medium, and at least one surface of the coupling lens includes a plurality of annular zones having a step concentric with an optical axis. The coupling lens is designed so that when a wavelength λ1=380 to 430 nm and a height of the step is d=m1λ1/(n1−1) where m1 is an actual number and n1 is a refractive index of the coupling lens at the wavelength λ1, 9.9≦m1≦10.1 is satisfied.
Public/Granted literature
- US20080137517A1 Coupling lens and optical pickup device Public/Granted day:2008-06-12
Information query
IPC分类: