Optical disc apparatus, focus control method and integrated circuit

A focus control method for shifting a focal point position of a light beam irradiated onto an optical disc having a plurality of recording layers from a first recording layer of the recording layers to a second recording layer of the recording layers, which is different from the first recording layer, the focus control method comprising:

• a focus control step of focusing the light beam on a predetermined recording layer of the recording layers of the optical disc;
• and
• a focus jump control step of controlling, when a focal point position of the light beam is shifted from the first recording layer to the second recording layer, a correction of spherical aberration which is generated in a light spot on the second recording layer and the shift of the focal point position of the light beam (i) based on an interlayer distance between the first recording layer and a third recording layer of the recording layers which adjoins the first recording layer in a direction opposite to a direction of the shifting of the focal point position of the light beam, and (ii) not based on another interlay distance between the first recording layer and the second recording layer.

An integrated circuit for shifting a focal point position of a light beam, which is irradiated onto an optical disc having a plurality of recording layers, from a first recording layer of the recording layers to a second recording layer of the recording layers, which is different from the first recording layer, the integrated circuit comprising:

• a focus control circuit which focuses a light beam on a predetermined recording layer of the recording layers of the optical disc;
• and
• a focus jump control circuit which controls, when a focal point position of the light beam is shifted from the first recording layer to the second recording layer, a correction of spherical aberration which is generated in a light spot on the second recording layer and the shift of the focal point position of the light beam (i) based on an interlayer distance between the first recording layer and a third recording layer of the recording layers which adjoins the first recording layer in a direction opposite to a direction of the shifting of the focal point position of the light beam, and (ii) not based on another interlay distance between the first recording layer and the second recording layer.