公开(公告)号：US20010009538A1

公开(公告)日：2001-07-26

申请号：US09741920

申请日：2000-12-20

Applicant: U.S. Philips Corporation

Inventor： Sjoerd Stallings ,  Joris Jan Vrehen ,  Jeroen Wals

IPC: G11B007/00

CPC classification number: G11B7/1369 ,  G11B7/0956 ,  G11B7/13927

Abstract: An optical head scans the information layer (3) of an optical record carrier (1) by means of a radiation beam (13). Optical aberrations in the beam such as coma and spherical aberration, caused by tilt and thickness variations in the optical disc respectively, are compensated by an aberration compensator (27) arranged in the radiation beam. The tilt or thickness variation is measured by a detector (30) and used to control the aberration compensator. The radiation beam is focused onto the information layer by an objective system (11). A displacement of the objective system in the transverse direction (26) as used for radial tracking of the optical beam, causes a mismatch between the wavefront to be compensated and the wavefront introduced by the aberration compensator (27). The detrimental effects of the mismatch are reduced by compensating only part of the aberration. The degree of compensation depends on the maximum displacement of the objective system and the tolerable wavefront error.

Abstract translation: 光头通过辐射束（13）扫描光学记录载体（1）的信息层（3）。 由光盘中的倾斜和厚度变化引起的诸如彗差和球面像差的光束中的光学像差由布置在辐射束中的像差补偿器（27）补偿。 倾斜或厚度变化由检测器（30）测量并用于控制像差补偿器。 辐射束通过客观系统（11）聚焦到信息层上。 用于光束的径向跟踪的​​横向（26）上的物镜系统的位移导致要补偿的波前与由像差补偿器（27）引入的波阵面之间的失配。 通过仅补偿部分像差来减少不匹配的有害影响。 补偿程度取决于物镜系统的最大位移和允许的波前误差。