| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device and an optical disk reproducing device, suitable for the case where a multilayer optical disk having a small distance between recording layers is used, capable of preventing offset without the mutual interferences of focus error signals from the recording layers. SOLUTION: A light from a semiconductor laser 1 is converged on an optical disk 6 by an objective lens 5, and its return light is guided to a light receiving element 7 by tripartite hologram element 2. The light receiving element 7 is provided with bisected main light receiving areas 7a and 7b for detective a focus error signal FES, and auxiliary light receiving areas 7e and 7f in both side of the outer side thereof for correcting the focus error signal. By setting the output signals of the light receiving areas 7a, 7b, 7e and 7f respectively as Sa, Sb, Se and Sf, a focus error signal is calculated by (Sa+Sf)-(Sb+Se), and an FES curve is improved outside a dynamic arrange, that is, in a large defocus state, and a beam is bulged out of the main light receiving areas 7a and 7b.
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