| 摘要 |
<p>A focus control device for an optical disc with land and groove portions is provided to control no focus difference in level between land and groove regions. The optical disc is provided with continuously formed land and groove regions. An optical pickup is used to write data on, or read data from, the optical disc. In this connection the focus control device is comprised of a land learning unit (1) for determining a focusing position of the land region, a groove learning unit (2) for determining a focusing position of the groove region, and a focus position operating unit (3) for determining a focusing position of a region where the land region is changed to the groove region. When a switching signal is changed in reverse in response to a position change from the land region to the groove region, the focus position of the optical pickup is moved so as to be a third focus position.</p> |
