| 摘要 |
The present invention relates to an optical pick, an optical drive device, and a light irradiation method capable of suppressing a generated amount of shift &Dgr;x of a spot position. The optical pickup irradiates an optical recording medium through a common objective lens which irradiates a first light for use in information recording in or information reproduction from a recording layer and a second light different from the first light, the optical recording medium includes a reference surface having a reflection film in which a position director is formed in a spiral form or the like form, and the recording layer which is provided in a layer position different from the reference surface and in which a mark corresponding to irradiation of light is formed and hence information is recorded. The optical pickup adjusts a focusing position of the first light having passed through the objective lens by changing collimation of the first light entering the objective lens, thereby suppressing the shift &Dgr;x of a spot position between the first light and the second light which occurs due to the eccentricity of the optical recording medium. A magnification of the second light is within a magnification range of the first light.
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