There has been a rapid advancement of research and development of a high density optical disc system capable of recording and/or reproducing (hereinafter, “recording and/or reproducing” will be described as “recording/reproducing”) information by using a violet semiconductor laser with a wavelength of about 400 nm. An example of the high density optical disc system records/reproduces information with specifications of NA 0.65 and light source wavelength of 405 nm to an optical disc, so-called HD DVD (hereinafter referred to as HD). In the system, information of about 15 GB per layer can be recorded for the optical disc having a diameter of 12 cm. Another example of the high density optical disc system records/reproduces information with specifications of NA 0.85 and light source wavelength of 405 nm for an optical disc, so-called Blu-ray Disc (hereinafter referred to as BD). In the system, information of about 25 GB per layer can be recorded for the optical disc having a diameter of 12 cm. Hereinafter, these optical discs will be referred as a “high density optical disc” in the present specification.
In order to achieve further increase of the storage capacity, the optical disc which provides a plurality of storage layers has been developed. In such an optical disc, the plurality of storage layers stores information which indicating the number of each layer, in advance. Therefore, the optical pickup apparatus for this kind of optical disc reads this information in an optical disc to select the recoding layer where information is recorded and/or reproduced, and moves an element such as a collimating lens to converge a light flux from a light source onto this recording layer, as disclosed in Unexamined Japanese Patent Application Publication No. 2005-293777.
When a vibration is given to the optical pickup apparatus and the collimator lens moves doe to the vibration, a light flux from the light source will be converged onto another recording layer, and there is a possibility that record/reproduction error may arise.