Liquid crystal lens for spherical aberration compensation in a Blu-ray disc system

Theoretical and experimental investigations into the use of a liquid crystal lens with a variable focal length for spherical aberration compensation in an optical pickup are presented. Spherical aberration is induced when the cover-layer thickness of the optical disc deviates from its nominal value. A convex liquid crystal lens is integrated into a Blu-ray standard conform optical pickup and tested with a 50 Gbyte dual-layer ROM disk. Excellent jitter values on the upper (6.8%) and on the lower (6.4%) data layer are achieved