Thin bias magnet unit for magneto-optical recording device

A magneto-optical disk device having a housing including a base and a side cover fixed to said base, a cartridge holder for holding and transferring an optical disk cartridge, a spindle motor that rotates an optical disk in said optical disk cartridge, and an optical head that projects an optical spot onto a recording or playing back portion of an optical disk, comprising:

• a loading mechanism that transfers said optical disk cartridge, when held by said cartridge holder, between an entry/exit position and a playing position by transferring said cartridge vertically;
• a bias magnet unit that includes a permanent magnet that applies a bias magnetic field to said projected optical spot, a driving coil that rotates said permanent magnet in order to switch a polarity of said bias magnetic field as applied to said projected optical spot, and a sensor to detect said polarity of said bias magnetic field;
• a stopper for limiting a rotational angle through which said magnet rotates so that a boundary place between an S pole and an N pole of said magnet is not in parallel with a plane of said optical disk in a stopped position of said magnet;
• a linkage structure for moving said magnet up and down including a pair of support arms, each having a central linear portion pivoted by bearings on an upper surface of said cartridge holder;
• and
• each said support arm further having first and second L-shaped portions at opposite end portions thereof, and a first tip at one end of said support arm adjacent said first L shaped portion that is engaged with a first hole provided on a side of said bias magnet unit and a second tip at the other end of said support arm adjacent said second L shaped member that is engaged with a first slot that is arranged on said side cover;
• wherein, for each said support arm, movement of said second tip in said slot causes rotational movement in said central linear portion to move up and down said first tip by movement of said first L shaped portion that causes up and down movement of said bias magnet unit.

A magneto-optical disk device having a housing including a base and a side cover fixed to said base, a cartridge holder for holding and transferring an optical disk cartridge, a spindle motor that rotates an optical disk in said optical disk cartridge, and an optical head that projects an optical spot onto a recording or playing back portion of an optical disk, comprising:

• a bias magnet for applying a magnetic field to said optical disk at said optical spot;
• a stopper for limiting a rotational angle through which said magnet rotates so that a boundary place between an S Pole and an N Pole of said magnet is not in parallel with a plane of said optical disk in a stopped position of said magnet;
• a linkage structure mounted on said cartridge holder in a space at a center of the cartridge holder that moves the bias magnet up and down;
• said linkage structure including arms that rotate around an axis that are secured on said cartridge holder.

A disk device having a housing including a base and a side cover fixed to said base, a cartridge holder for holding and transferring an optical disk cartridge, a spindle motor that rotates an optical disk in said optical disk cartridge, and an optical head that projects an optical spot onto a recording or playing back portion of an optical disk, comprising:

• a permanent magnet that applies a magnetic field to a disk medium in said disk cartridge;
• a stopper for limiting a rotational angle through which said magnet rotates so that a boundary place between an S Dole and an N pole of said magnet is not in parallel with a plane of said optical disk in a stopped position of said magnet;
• a linkage structure mounted on said cartridge holder in a space at a center of the cartridge holder that moves the bias magnet up and down;
• a driving coil in said linkage structure that rotates said permanent magnet in order to switch a polarity of said magnetic field;
• and
• said linkage structure including arms that rotate around an axis that are secured on said cartridge holder.

A disk device having a housing including a base and a side cover fixed to said base, a cartridge holder for holding and transferring an optical disk cartridge, a spindle motor that rotates an optical disk in said optical disk cartridge, and an optical head that projects an optical spot onto a recording or playing back portion of an optical disk, comprising:

• a permanent magnet that applies a magnetic field to a disk medium in said disk cartridge;
• a stopper for limiting a rotational angle through which said magnet rotates so that a boundary place between an S pole and an N pole of said magnet is not in parallel with a plane of said optical disk in a stopped position of said magnet;
• a linkage structure mounted on said cartridge holder in a space at a center of the cartridge holder that moves the bias magnet up and down;
• a loading mechanism that transfers said disk cartridge horizontally and vertically from a loading position to a playing position together with said cartridge holder;
• said linkage structure including arms that rotate according to said vertical transfer of said disk cartridge around axes that are secured on said cartridge holder.