Information readout method for non mask layer type optical information medium
- 申请公布号：
- US7859968(B2)
- 申请号：
- US20090352304
- 申请日期：
- 2009.01.12
- 申请公布日期：
- 2010.12.28
- 申请人：
- TDK CORPORATION
- 发明人：
- KIKUKAWA TAKASHI;KATO TATSUYA;UTSUNOMIYA HAJIME;SHINGAI HIROSHI
- 分类号：
- G11B7/0045;G11B7/24;G11B7/00;G11B7/005;G11B7/125;G11B11/105
- 主分类号：
- G11B7/0045
- 摘要：
- An information readout method for an optical information medium comprising an information recording layer having pits or recorded marks representative of information data involves the step of irradiating a laser beam to the information recording layer through an objective lens for providing readings of the pits or recorded marks. When the laser beam has a wavelength λ of 400 to 410 nm, the objective lens has a numerical aperture NA of 0.70 to 0.85, and the pits or recorded marks have a minimum size PL of up to 0.36λ/NA, readout is carried out at a power Pr of at least 0.4 mW for the laser beam. When the laser beam has a wavelength λ of 630 to 670 nm, the objective lens has a numerical aperture NA of 0.60 to 0.65, and the pits or recorded marks have a minimum size PL of up to 0.36λ/NA, readout is carried out at a power Pr of at least 1.0 mW for the laser beam. Pits or recorded marks of a size approximate to the resolution limit determined by diffraction can be read out at a high C/N.
Copyright Notice © 2009-2024 传众 版权所有