An optical pickup wherein a main beam and at least two sub-beams are collected on a disc and a tracking error signal is detected from each of push pull signals. A phase of the push pull signal generated from the first sub-beam is shifted from a phase of the push pull signal generated from the second sub-beam by substantially 180°. A phase difference is given to a part of the first sub-beam (10) and a part of the second sub-beam (11) by a diffraction optical element (2) which generates the first sub-beam (10) and the second sub-beam (11).
申请公布号
KR20070104208(A)
申请公布日期
2007.10.25
申请号
KR20067026738
申请日期
2006.12.19
申请人
MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
发明人
ONO MASAYUKI;NISHIMOTO MASAHIKO;NAKAMORI TATSUYA;NAKANISHI NAOKI