Abstract: The present invention provides a planer acoustic transducer including a vibrating diaphragm including a spiral voice coil provided on both surfaces or on one surface of an insulating base film; and a permanent magnet corresponding to the voice coil, wherein, in the vibrating diaphragm, the spiral voice coil is formed by applying a wire conductor, in a coil pattern, onto a sheet-like substrate having an adhesive layer on at least one surface thereof. Alternatively, at least a portion of the vibrating diaphragm, which portion corresponds to the loop of a first or second vibration mode, is reinforced with a rigidity-imparting member; the substrate of the vibrating diaphragm is formed of a resin foam; or the voice coil is formed three-dimensionally.

Abstract: The present invention provides a planer acoustic transducer including a vibrating diaphragm including a spiral voice coil provided on both surfaces or on one surface of an insulating base film; and a permanent magnet corresponding to the voice coil, wherein, in the vibrating diaphragm, the spiral voice coil is formed by applying a wire conductor, in a coil pattern, onto a sheet-like substrate having an adhesive layer on at least one surface thereof. Alternatively, at least a portion of the vibrating diaphragm, which portion corresponds to the loop of a first or second vibration mode, is reinforced with a rigidity-imparting member; the substrate of the vibrating diaphragm is formed of a resin foam; or the voice coil is formed three-dimensionally.

Abstract: An electro-acoustic transducer, such as a loudspeaker, a microphone, or the like, comprises a magnetic circuit having at least one air gap, a current conductor disposed in the air gap of the magnetic circuit to form a voice coil which is traversed by magnetic flux, and a vibratory structure mechanically coupled to the voice coil. The vibratory structure is comprised of a heat resistant film containing an epoxide-modified resin in which a heterocyclic compound containing a polyimide group is the main component. The voice coil is non-adhesively secured to the vibratory structure. For example, the voice coil is formed of a conductive substrate onto which the vibratory structure is coated and from which portions have been etched to form a generally spiral-shaped conductor. In one embodiment, the vibratory structure is a diaphragm; and in another embodiment, the vibratory structure is a bobbin having the voice coil wound thereon.

Abstract: A diaphragm for a loudspeaker includes a core member having a flat front surface from which a frustum-shaped side surface extends to a back portion, a cover member secured to the back portion and adapted to be connected to a voice coil bobbin of the loudspeaker, an outer radiation layer mounted on the front surface and having a relatively high resonance sharpness, and an intermediate layer laminated between the front surface and the outer radiation layer and having a resonance sharpness lower than that of the outer radiation layer.

Abstract: In an enclosed loudspeaker apparatus comprising a transducer, such as a loudspeaker, for producing acoustic radiation or sound when an electric current is applied to a drive means of the transducer, and an enclosure having an aperture in which the transducer is mounted for emission of the acoustic radiation therethrough with the drive means being in the interior of the enclosure; a heat pipe is provided for absorbing heat generated by electric current applied to the drive means, and for carrying such heat to the exterior of the enclosure so as to permit the application of increased currents to the drive means without overheating.