US Patent 7969853 Optical pickup device

A servo objective lens and a recording/reproducing objective lens are commonly held on a holder. The servo objective lens and the recording/reproducing objective lens are integrally displaced, thereby pulling servo light onto a servo layer. Upon the pulling, focus positions of recording light and reproducing light follow a focus position of the servo light. As a result, the focus positions of recording light and reproducing light are set close to the servo layer. Thereafter, an optical element for displacing the focus positions of recording light and reproducing light in the optical axis direction is driven to pull the recording light and the reproducing light onto a targeted recording layer.