Optical element driving device having two permanent magnets and one magnetic substance

摘要

Tracking coils are fixed on side surfaces of a lens holder and a magnetic substance of axisymmetric shape is fixed on a lower surface of the lens holder, being sandwiched by a focusing coil. Moreover, end portions of the magnetic substance are opposed to respective N-pole surfaces of permanent magnets serving as a focusing driving device and a tracking driving device together with the above coils. As a result, a neutral position holding system for an objective lens can be formed of these permanent magnets and the magnetic substance.