发明名称 |
Magneto-optical disc system having an objective lens with a numerical aperture related to the thickness of the protective layer |
摘要 |
An magneto-optical disc system includes an magneto-optical disc with a light-transmitting cover and an objective lens for bundling or focusing a laser beam on a recording layer of the magneto-optical disc in order to perform recording and/or reproduction. The thickness t2 of the light-transmitting cover is set to fall within the range of 0.6 to 0.1 mm, the numerical aperture (NA) of the objective lens is set to fall within the range of 0.55 to 0.70 and the wavelength of the light beam is selected to be between 635 and 680 nanometers.
|
申请公布号 |
US5617378(A) |
申请公布日期 |
1997.04.01 |
申请号 |
US19950499347 |
申请日期 |
1995.07.07 |
申请人 |
SONY CORPORATION |
发明人 |
WATANABE, TETSU;AOKI, YOSHIO |
分类号 |
G11B7/007;G11B7/135;G11B7/24;G11B11/105;(IPC1-7):G11B11/00 |
主分类号 |
G11B7/007 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|