Abstract: A magnetic circuit includes a magnet, a first plate, and a yoke, and has a magnetic gap. The first plate and the yoke are joined to the magnet. The magnet includes first and second magnet parts. The second magnet part has a lower magnetic property than that of the first magnet part. Such a first magnet part is disposed in a vicinity of the magnetic gap. On the other hand, the second magnet part is disposed farther from the magnetic gap than the first magnet part. The first and second magnet parts are connected in parallel to each other. With this configuration, the second magnet part makes a small contribution to the magnetic flux density in the magnetic gap. Therefore, the magnetic property of the second magnet part may be low, and an inexpensive magnet can be used as the second magnet part.

Abstract: A magnetic circuit includes a magnet, a first plate, and a yoke, and has a magnetic gap. The first plate and the yoke are joined to the magnet. The magnet includes first and second magnet parts. The second magnet part has a lower magnetic property than that of the first magnet part. Such a first magnet part is disposed in a vicinity of the magnetic gap. On the other hand, the second magnet part is disposed farther from the magnetic gap than the first magnet part. The first and second magnet parts are connected in parallel to each other. With this configuration, the second magnet part makes a small contribution to the magnetic flux density in the magnetic gap. Therefore, the magnetic property of the second magnet part may be low, and an inexpensive magnet can be used as the second magnet part.

Abstract: A bond magnet according to the present invention is anisotropic, and a magnetic field is oriented from a lowest edge of side surface of the bond magnet toward an upper section of side surface of the bond magnet. Further, the bond magnet is configured such that the upper section of side surface of the bond magnet is disposed closer to a yoke side surface of a yoke than the lower side surface of the bond magnet is, and the upper section of side surface of the bond magnet faces against the yoke side surface. With this, a magnetic gap is provided between the upper section of side surface of the bond magnet and the yoke side surface. Thus, it is possible to improve a magnetism characteristic of the bond magnet, and to achieve both of magnetic efficiency and productivity of a magnetic circuit for a speaker.

Abstract: A bond magnet according to the present invention is anisotropic, and a magnetic field is oriented from a lowest edge of side surface of the bond magnet toward an upper section of side surface of the bond magnet. Further, the bond magnet is configured such that the upper section of side surface of the bond magnet is disposed closer to a yoke side surface of a yoke than the lower side surface of the bond magnet is, and the upper section of side surface of the bond magnet faces against the yoke side surface. With this, a magnetic gap is provided between the upper section of side surface of the bond magnet and the yoke side surface. Thus, it is possible to improve a magnetism characteristic of the bond magnet, and to achieve both of magnetic efficiency and productivity of a magnetic circuit for a speaker.

Abstract: A diaphragm for a loudspeaker contains resin, aramid fibers, and an organic silicon compound binding the resin with the aramid fibers. By this structure, high elasticity and high internal loss as characteristics of the aramid fibers are maintained; flexibility in the setting of properties of the diaphragm is thus increased. Accordingly, a diaphragm securing humidity resistance reliability and strength, and having a superior appearance can be provided.

Abstract: A speaker diaphragm or a dust cap formed by injection molding a mixture at least containing a resin material and a fiber material. The speaker diaphragm or the dust cap combines the advantages of both a paper diaphragm and a resin diaphragm. The advantage of a paper diaphragm is a large degree of freedom in setting physical properties. The advantages of a resin diaphragm are being excellent in moisture resistance reliability, strength, external appearance, productivity and dimension stability.

Abstract: A thermally conductive substrate includes a thermally conductive resin sheet member attached to a lead frame. The lead frame comprises a thermally conductive resin sheet member and it is integrated with the thermally conductive resin sheet member on the lead frame. The thermally conductive resin sheet member is formed from a thermosetting resin mixture which comprises 70 to 90 parts by weight of an inorganic filler and 5 to 30 parts by weight of a thermosetting resin composition including a thermosetting resin, and the thermosetting resin is in a semi-cured state.

Abstract: A thermally conductive substrate includes a thermally conductive resin sheet member attached to a lead frame. The lead frame comprises a thermally conductive resin sheet member and it is integrated with the thermally conductive resin sheet member on the lead frame. The thermally conductive resin sheet member is formed from a thermosetting resin mixture comprises 70 to 90 parts by weight of an inorganic filler and 5 to 30 parts by weight of a thermosetting resin composition including a thermosetting resin, and the thermosetting resin is in a semi-cured state.

Abstract: A lead frame of a circuit board is punched in a direction opposite to a heat sink plate. Even if burrs are produced due to the punching, the burrs do not penetrate a sheet or short-circuit to the heat sink plate. A resist film tightly contacts on the periphery of a land of the lead frame of the circuit board, and a plated layer tightly contacts on the land. This prevents electronic components from defective mounting on the land.

Abstract: A thermally conductive substrate includes a thermally conductive resin sheet member attached to a lead frame. The lead frame comprises a thermally conductive resin sheet member and it is integrated with the thermally conductive resin sheet member on the lead frame. The thermally conductive resin sheet member is formed from a thermosetting resin mixture which comprises 70 to 90 parts by weight of an inorganic filler and 5 to 30 parts by weight of a thermosetting resin composition including a thermosetting resin, and the thermosetting resin is in a semi-cured state.

Abstract: A circuit board comprising a composite resin and a metal plate, the metal plate forming circuit patterns. The composite resin comprises 70-95 parts by weight of inorganic filler, and 5-30 parts by weight of a resin composition including a thermosetting resin and a hardener. The metal plate is surface treated to reinforce the adhesion at least at one surface contacting with the composite resin. The composite resin fills spaces between the circuit patterns, and the composite resin composition and the metal plate form a plane at a side of the metal plate for mounting components. Since the resin composition including the inorganic filler is also present in the spaces between circuit patterns of a metal plate, heat dissipation characteristic of the circuit board is extremely high, and is suited for electronic apparatus containing heat generating parts such as power circuit.

Abstract: The present invention relates to an electromagnetic electro-acoustic transducer to be used for generating an incoming indicator tone for mobile phones and the like. A resin magnet 11 is formed with a hard magnetic material and a soft magnetic material, the lowest resonant frequency can be easily set by changing the magnetic flux density in a magnetic gap by changing the compound ratio of the soft magnetic material, a high magnetic flux density is attained by increasing the magnetic permeability of the resin magnet 11 with the soft magnetic material, thus achieving a smaller size as well as a higher sound pressure through an increase in the driving force exerted to the diaphragm.

Abstract: A lead frame of a circuit board is punched in a direction opposite to a heat sink plate. Even if burrs are produced due to the punching, the burrs do not penetrate a sheet or short-circuit to the heat sink plate. A resist film tightly contacts on the periphery of a land of the lead frame of the circuit board, and a plated layer tightly contacts on the land. This prevents electronic components from defective mounting on the land.

Abstract: In the production of a thermally conductive substrate, a thermally conductive resin sheet member attaching lead frame is provided for the purpose of suppressing the formation of resin burrs and surface stains on surfaces of the lead frame and also “Takt” for the production of the thermally conductive substrate is shortened.

Abstract: A circuit board of the present invention comprises a composite resin and a metal plate, and the metal plate forms circuit patterns. The metal plate is preferably made of copper or copper alloys having excellent heat conductivity. The composite resin comprises 70-95 parts by weight of inorganic filler, and 5-30 parts by weight of a resin composition including a thermosetting resin and a hardener. The metal plate is surface roughened or treated to reinforce the adhesion at least at one surface contacting with the composite resin. In the circuit board of the present invention, the composite resin fills spaces between the circuit patterns, and the composite resin composition and the metal plate form a plane at the side of the metal plate for mounting components.