| 摘要 |
<p>Provided is an optical pickup device that utilizes an antireflection film so as to be able to form an optimal focused spot even when a light beam with a relatively large divergence angle is incident on an objective lens at the time of a focus jump. In the objective lens on which the antireflection film is formed, if the transmittance (Tc) of the central region of a circle formed within the 10% range from the center of the effective diameter of a first surface and the transmittance (Tp) of an annular peripheral region formed outside the 90% range of the effective diameter of the first surface are set to meet equation (1), the rim intensity (perimeter intensity) of the spotlight is increased such that a so-called super-resolution phenomenon occurs, allowing the diameter of the focused spot to be reduced. Consequently, an optimal focused spot can be formed even in the event when a light beam with a relatively large divergence angle is incident on the objective lens. Thus, the recording/reproducing characteristics of the optical pickup device can be improved. 1.0<Tp/Tc<1.3 (1)</p> |
