US 5,471,100 AGranted

Linear electromagnetic driving apparatus and use of same for lens adjustment

AssigneeSony Corporation

InventorsSatoshi Sakamoto, Shinichi Orimo

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Abstract

A linear electromagnetic driving apparatus includes a substantially rectangular tube-shaped magnetic yoke comprised of outer and inner frame plates spaced apart to form a gap with at least one magnet secured to an outer or inner frame plate to generate magnetic flux. A bobbin supporting a coil which extends in a direction parallel to the longitudinal axis of the magnetic yoke is positioned in the gap. A driven member is secured to and coaxial with the bobbin and has openings to receive the inner frame plates of the yoke such that when the coil is energized to move the bobbin in the gap, the inner frame plates extend into and through the bobbin and into and through the openings of the driven member. A fixed shaft extends parallel to the longitudinal axis of the yoke; and a bearing secured to the bobbin structure and extending outwardly therefrom receives and is slidable on the fixed shaft. At least one of the corners formed on the rectangular tube-shaped yoke is cut out to define an open portion through which the bearing passes so as to be unobstructed as the bobbin slides within the yoke.

Claims39

Dependent claims

Linear electromagnetic driving apparatus comprising stator means including a substantially rectangular tube-shaped magnetic yoke comprised of outer frame plates, inner frame plates spaced from and facing said outer frame plates to form a gap therebetween, a connecting member for connecting the outer and inner frame plates and providing a magnetic flux path therethrough and at least one magnet secured to one of said outer and inner frame plates to generate said magnetic flux, said rectangular tube-shaped magnetic yoke having a longitudinal axis and also having corners, at least one of said corners being cut out to define an open portion;

movable means slidable within said gap between said outer and inner frame plates and including a drive member comprised of a bobbin positioned within said gap and a coil wound on said bobbin and extending in a direction parallel to said longitudinal axis, a driven member secured to and coaxial with said bobbin and having openings to receive said inner frame plates of said yoke means such that when said coil is energized to move said movable means in said gap, said inner frame plates extend into and through said bobbin and into and through the openings of said driven member;
a fixed shaft extending parallel to said longitudinal axis of the rectangular tube-shaped magnetic yoke;
and bearing means secured to said movable means and extending outwardly therefrom substantially perpendicular to said longitudinal axis and passing through the open portion of said at least one corner of said rectangular tube-shaped magnetic yoke, said bearing means receiving and being slidable on said fixed shaft.

Electromagnetically driven focusing apparatus comprising stator means including a substantially rectangular tube-shaped magnetic yoke comprised of outer frame plates, inner frame plates spaced from and facing said outer frame plates to form a gap therebetween, a connecting member for connecting the outer and inner frame plates and providing a magnetic flux path therethrough and at least one magnet secured to one of said outer and inner frame plates to generate said magnetic flux, said rectangular tube-shaped magnetic yoke having a longitudinal axis and also having corners, at least one of said corners being cut out to define an open portion;

movable means slidable within said gap between said outer and inner frame plates and including a drive member comprised of a bobbin positioned within said gap and a coil wound on said bobbin and extending in a direction parallel to said longitudinal axis, lens holding means secured to and coaxial with said bobbin for holding a lens and having openings to receive said inner frame plates of said yoke means such that when said coil is energized to move said movable means in said gap, said inner frame plates extend into and through said bobbin and into and through the openings of said lens holding means;
a fixed shaft extending parallel to said longitudinal axis of the rectangular tube-shaped magnetic yoke;
and bearing means secured to said movable means and extending outwardly therefrom substantially perpendicular to said longitudinal axis and passing through the open portion of said at least one corner of said rectangular tube-shaped magnetic yoke, said bearing means receiving and being slidable on said fixed shaft.

Lens drive apparatus for moving a lens in a camera comprising stator means including a substantially rectangular tube-shaped magnetic yoke comprised of outer frame plates, inner frame plates spaced from and facing said outer frame plates to form a gap therebetween, a connecting member for connecting the outer and inner frame plates and providing a magnetic flux path therethrough and at least one magnet secured to one of said outer and inner frame plates to generate said magnetic flux, said rectangular tube-shaped magnetic yoke having a longitudinal axis and also having corners, at least one of said corners being cut out to define an open portion;

movable means slidable within said gap between said outer and inner frame plates and including a drive member comprised of a bobbin positioned within said gap and a coil wound on said bobbin and extending in a direction parallel to said longitudinal axis, lens holding means secured to and coaxial with said bobbin for holding a lens and having openings to receive said inner frame plates of said yoke means such that when said coil is energized to move said movable means in said gap, said inner frame plates extend into and through said bobbin and into and through the openings of said lens holding means;
a fixed shaft extending parallel to said longitudinal axis of the rectangular tube-shaped magnetic yoke;
and bearing means secured to said movable means and extending outwardly therefrom substantially perpendicular to said longitudinal axis and passing through the open portion of said at least one corner of said rectangular tube-shaped magnetic yoke, said bearing means receiving and being slidable on said fixed shaft.

Dependencies are inferred from the claim text.