<p>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).</p>
申请公布号
WO2006087843(A1)
申请公布日期
2006.08.24
申请号
WO2005JP17338
申请日期
2005.09.21
申请人
MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.;ONO, MASAYUKI;NISHIMOTO, MASAHIKO;NAKAMORI, TATSUYA;NAKANISHI, NAOKI