发明授权
- 专利标题: Multi-layer record carrier and method of manufacturing thereof and recording thereon, with reduced transmission differences in the upper layer
- 专利标题(中): 多层记录载体及其制造方法和记录在上层的传输差异减小
-
申请号: US09994272申请日: 2001-11-26
-
公开(公告)号: US07215634B2公开(公告)日: 2007-05-08
- 发明人: Roel Van Woudenberg
- 申请人: Roel Van Woudenberg
- 申请人地址: NL Eindhoven
- 专利权人: Koninklijke Philips Electronics N. V.
- 当前专利权人: Koninklijke Philips Electronics N. V.
- 当前专利权人地址: NL Eindhoven
- 优先权: EP00204730 20001222; EP01200894 20010309
- 主分类号: G11B7/00
- IPC分类号: G11B7/00
摘要:
A multi-layer record carrier and method of manufacturing thereof and recording thereon, includes data written in units of blocks on tracks of at least two information layers. A first guard field is written at the start of a data block and a second guard field is written at the end of the data block. The power in the focused spot in the deepest of the at least two information layers is maintained substantially at an optimal value, by setting the length of the first and second guard fields such that the end position of the second guard field of a preceding data block is located within the area of the first guard field of the succeeding data block. Thereby, gap portions between the first and second guard fields can be prevented. Alternatively, the length of the first and second guard fields is set to be approximately equal to the sum of half the diameter of a recording beam in the upper one of the at least two information layers when focused on the lowest one of the at least two information layers and a maximum allowed misalignment between the two layers. Thereby, the area through which the beam passes in the information layer is of a uniform nature, when user data is being read or written. The at least two information layers are aligned by optically measuring and aligning alignment marks, such as header spokes, at predetermined measuring points.
公开/授权文献
信息查询
IPC分类: