A multilayer circuit structure has a number of electrically conductive trace layers, separated from each other by a number of electrically insulating layers. The thickness of any given one of the conductive trace layers is greater than the thickness of its adjacent one of the insulating layers. Also, each of the conductive trace layers is bonded to an adjacent one of the insulating layers, and is electrically joined to an adjacent one of the conductive trace layers through a gap in the adjacent one of the insulator layers that is between them. Other aspects are also described and claimed.

The periodic magnetic field generator includes a flat-shaped first yoke, and a plurality of main permanent magnets, an auxiliary permanent magnet, and a side permanent magnet on the first yoke. The plurality of main permanent magnets are magnetized in a first direction of generating magnetic fields, the direction being perpendicular to the first yoke, and disposed such that orientations of the magnetization become opposite alternately in the first direction. The auxiliary permanent magnet is magnetized in a second direction perpendicular to side faces of the plurality of main permanent magnets, and placed between the side faces of the main permanent magnets. The side permanent magnet is magnetized in a third direction perpendicular to the first direction, and disposed so as to cover end faces of the main permanent magnets and the auxiliary permanent magnet, the end faces being perpendicular to the side faces of the main permanent magnets.

Several embodiments of the instant invention incorporate a loudspeaker design utilizing hard magnetic poles and yokes. The magnetic field of the loudspeaker is created and guided with a series of critically formed hard magnetic structures guiding the magnetic field from the primary magnet to the gap in a loop of hard magnetic material, replacing the soft magnetic materials normally used. Magnetization of the components of the hard magnetic loudspeaker driver with radial pole patternsa yoke radial magnet, a washer pole magnet and a yoke upper ring magnetis performed with these components in their final assembly relationships.

The present invention relates to a permanent magnet suitable for a magnetic angle encoder. The permanent magnet has an annular cylindrical structure and comprises a first permanent magnet unit and a second permanent magnet unit. The first permanent magnet unit and the second permanent magnet unit are geometrically symmetrical with respect to a diametral cross section. The magnetization intensity of the first permanent magnet unit and the magnetization intensity of the second permanent magnet unit are parallel to the axial direction of the annular cylinder and are in opposite directions, or the magnetization intensity of the first permanent magnet unit and the magnetization intensity of the second permanent magnet unit are perpendicular to the diametral cross section and are parallel to one another and in the same direction.

Several embodiments of the instant invention incorporate a loudspeaker design utilizing hard magnetic poles and yokes. The magnetic field of the loudspeaker is created and guided with a series of critically formed hard magnetic structures guiding the magnetic field from the primary magnet to the gap in a loop of hard magnetic material, replacing the soft magnetic materials normally used. Magnetization of the components of the hard magnetic loudspeaker driver with radial pole patternsa yoke radial magnet, a washer pole magnet and a yoke upper ring magnetis performed with these components in their final assembly relationships.

An audio speaker having a magnet assembly for directing a magnetic field through a magnetic circuit, and an electrical circuit for carrying an electrical audio signal current through at least part of the magnet assembly, are disclosed. More particularly, a voicecoil in the electrical circuit may be in electrical contact with a magnetic plate of the magnet assembly. The voicecoil may be electrically connected with a speaker driver circuit at least partly through the magnetic plate. Other embodiments are also described and claimed.

A compact electromagnetic actuator for driving a lens includes a lens holder used to hold a lens or a lens assembly which defines an optical axis, an image stabilization (IS) actuator provided at one end of the lens holder for producing a linear motion in a plane perpendicular to the optical axis, and an autofocus (AF) actuator provided at an opposite end of the lens holder for producing a linear motion along the optical axis. An AF connection mechanism can be used to connect the autofocus actuator to the lens holder. An IS connection mechanism can be used to connect the image stabilization actuator to the lens holder.

An optical member driving device includes an optical member that light is incident on; and a plurality of actuators that shift different portions of an outer peripheral edge of the optical member in a traveling direction of the light immediately before the light is incidence. Each of the plurality of actuators includes an arm that rotates about a rotation center line extending in a direction perpendicular to the traveling direction and supports the optical member at a first end of the arm, a conductor that is provided at a second end of the arm and extends in a direction from the second end toward the first end, the conductor being where a current flows, and a magnet pair that is provided to sandwich the second end of the arm at an interval and generates a magnetic field in a direction intersecting with a direction where the conductor extends.

An object of the present invention is to provide a magnetic circuit for an acoustic transducer, the magnetic circuit enabling peeling of the surface of a member formed by compression-molding a soft magnetic composite material to be suppressed. The present invention is a magnetic circuit for an acoustic transducer, the magnetic circuit including: a yoke 151; a magnet 152; and a top plate 153, wherein the yoke 151 includes a bottom surface portion 151a and a pole piece 151b provided perpendicular to the bottom surface portion 151a, the magnet 152 and the top plate 153 are provided in that order on the bottom surface portion 151a, a magnetic gap 141 in which a voice coil 14 is disposed is formed between the pole piece 151b and the top plate 153, at least one of the pole piece 151b and the top plate 153 includes: a composite material part 154 in a position facing the magnetic gap 141; and a protective layer 155 covering at least a surface of the composite material part 154, the composite material part 154 is formed from a soft magnetic composite material, and the material of the protective layer 155 differs from the soft magnetic composite material.

In a linear motor for a hydraulic device, a permanent magnet includes, in a longitudinal direction, first and second magnets on proximal and distal sides of the hydraulic device. A first coil and a second coil are formed by winding coil wires in opposite directions. An LVDT case member in which solenoid coils constituting an LVDT in a region in front of an end of the first magnet closer to the hydraulic device are built is projected at an end of an inner yoke on the hydraulic device side. A core of the LVDT linearly moveable together with the bobbin inside the solenoid coils is coupled to a protrusion extending in a substantially cone shape from an edge of a cylindrical body of the bobbin. A magnetic ring of a soft magnetic material is disposed in contact with the end of the first magnet closer to the hydraulic device.