| 摘要 |
An optical pickup apparatus for reading out information from an optical disk. The optical pickup apparatus comprises a light source (1) and an optical device (2) having a grating pattern for splitting a light beam from said source into a zero-order diffracted beam and plus and minus first-order diffracted beams. The grating pattern has a centre portion (a) and one or more side portions (b). The efficiency of the centre portion (a) for the zero-order diffracted beam is greater than the efficiency of the side portions (b) for the zero-order diffracted beam. |
