Actuator for an objective lens of an optical pickup for preventing skew of the optical axis

An actuator for an objective lens, having a lens holder for holding said objective lens;

• a coil bobbin wound with a focusing coil and at least one tracking coil, said coil bobbin being fixed on said lens holder;
• a magnetic field generator for generating a magnetic field for driving said lens holder with said focusing coil and said at least one tracking coil;
• and a plurality of elastic supporting members for supporting said lens holder such that said lens holder is moveable along an arc a tangent of which is in a direction parallel to an optical axis of said lens, said optical axis shifting with respect to a fixed member as said lens holder moves about said arc, wherein first end portions of said supporting members are fixed to said lens holder and second end portions of said supporting members are fixed to said fixed member;
• the improvement comprising:
• an expanding and contracting portion associated with each of said supporting members which expands or contracts along a longitudinal direction of said supporting members to prevent a shift of said optical axis when said lens holder is driven.

An actuator for an objective lens, comprising:

• a lens holder for holding said objective lens;
• a coil bobbin wound with a focusing coil and at least one tracking coil, said coil bobbin being fixed on said lens holder;
• a magnetic field generator for generating a magnetic field for driving said lens holder with said focusing coil and said at least one tracking coil;
• and
• a plurality of elastic supporting members for supporting said lens holder such that said lens holder is moveable in a direction parallel to an optical axis of said lens and a direction perpendicular to the optical axis of said lens, first end portions of said:supporting members being fixed to said lens holder and second end portions of said supporting members being fixed to a fixed member;
• wherein said supporting members each comprise an expanding and contracting portion which expands or contracts to vary the length of the supporting member when said lens holder is driven to prevent a shift of said optical axis with respect to said fixed member, wherein all of said supporting members are fixed to said fixed member in a common plane.

An actuator for an objective lens, comprising:

• a lens holder for holding said objective lens;
• a coil bobbin wound with a focusing coil and at least one tracking coil, said coil bobbin being fixed on said lens holder;
• a magnetic field generator for generating a magnetic field for driving said lens holder with said focusing coil and said at least one tracking coil;
• and
• a plurality of elastic supporting members for supporting said lens holder such that said lens holder is moveable in a direction parallel to an optical axis of said lens and a direction perpendicular to the optical axis of said lens, first end portions of said supporting members being fixed to said lens holder and second end portions of said supporting members being fixed to a fixed member;
• wherein said supporting members are made of an electrically conductive material and each have an expanding and contracting portion which expands or contracts to vary the length of the supporting member when said lens holder is driven to prevent a shift of said optical axis with respect to said fixed member.