发明名称 |
Dispositivo e processo de exploração óptica |
摘要 |
An optical scanning device can scan two types of record carriers each having a transparent layer with a different thickness, in which a focused radiation beam scans an information layer of the record carrier through the transparent layer. When scanning a first type of record carrier the best focus of the radiation beam is positioned on the information layer and when scanning a second type of record carrier the paraxial focus of the radiation beam is positioned on the information layer. The lens system focusing the radiation beam comprises an opaque ring between a transparent central area and a transparent annular area. |
申请公布号 |
BR9702117(A) |
申请公布日期 |
1999.01.26 |
申请号 |
BR19979702117 |
申请日期 |
1997.02.25 |
申请人 |
PHILIPS ELECTRONICS N.V. |
发明人 |
JOSEPHUS JOHANNES MARIA BRAAT |
分类号 |
G02B3/00;G11B7/00;G11B7/09;G11B7/1353;G11B7/1374;G11B7/1381;G11B7/1392 |
主分类号 |
G02B3/00 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|