Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Kousaku Murata

Takashi Ogura

Shuji Saiki

Satoshi Takayama

Hiroyuki Takewa

Shuichi Obata

Kazue Sato

Tsuneo Tanaka

Katsuaki Satoh

Hiroshi Yamamoto

Osamu Yamamoto

Kenichi Terai

Sawako Usuki

Mitsuhiko Serikawa

Yasutoshi Nakama

Seiichi Ishikawa

Michiko Ogawa

Yoichi Kimura

Takashi Takeda

Naraji Sakamoto

Kazumasa Yamamoto

Yoichi Kumura

A piezoelectric speaker comprises a plurality of diaphragms, connecting components, and piezoelectric elements. The plurality of diaphragms are each formed by a laminated material in which a core layer made of an insulating material is laminated to skin layers each made of a conductive material so as to form the skin layers on both surfaces of the core layer. The connecting components each corresponds to a plate-shaped component of the insulating material and connects between at least two of the plurality of diaphragms. Piezoelectric elements are mounted on surfaces of the plurality of diaphragms, respectively. The plurality of diaphragms are insulated from each other such that separate voltages are applied to the piezoelectric elements mounted thereon, respectively.

Piezoelectric speaker and method for manufacturing the same

A piezoelectric speaker improved in acoustic features by weight reduction of a diaphragm of the piezoelectric speaker without decreasing stiffness of the diaphragm or a coefficient of thermal expansion of surfaces of the piezoelectric speaker is provided. The diaphragm having placed thereon a piezoelectric element is made of a sandwich-laminate clad material using different materials. For example, surface materials made of 42 alloy each having a thickness of 10 &#x3bc;m and a core material made of aluminium having a thickness of 30 &#x3bc;m form a clad material having a thickness of 50 &#x3bc;m. The formed clad material is processed into an arbitrary shape to form the diaphragm of the piezoelectric speaker. With this diaphragm, it is possible to keep the stiffness and the coefficient of thermal expansion of the 42-alloy diaphragm having the thickness of 50 &#x3bc;m, and also achieve weight reduction by approximately 40%.

Piezoelectric speaker

A piezoelectric speaker is manufactured by processing a plate to form a frame, a plurality of vibrating plates and a plurality of dampers. The plurality of dampers are connected to the frame and the plurality of vibrating plates so that each of the plurality of vibrating plates linearly vibrates. At least one piezoelectric element is arranged on the plurality of vibrating plates. An edge is formed for preventing air from leaking through a gap among the plurality of vibrating plates, the plurality of dampers, and the frame.

Method for producing a piezoelectric speaker

A piezoelectric speaker includes a frame; a vibrating plate; a piezoelectric element provided on the vibrating plate; a damper connected to the frame and to the vibrating plate for supporting the vibrating plate so that the vibrating plate linearly vibrates; and an edge for preventing air from leaking through a gap between the vibrating plate and the frame.

Piezoelectric speaker, method for producing the same, and speaker system including the same

A diaphragm for speakers comprises a self-support, shaped body including a tightly woven synthetic polymer fiber cloth substrate which has, at least a diaphragm portion and edge portion shaped integrally with and extending from the diaphragm portion. The diaphragm portion of the cloth substrate had a polymer resin at least partially impregnated therein and the edge portion has a relatively flexible polymer material at least partially impregnated therein so that the edge portion is lower in stiffness than the diaphragm portion. The diaphragm-edge integral molding is fabricated by applying the respective types of polymers to the diaphragm and edge portions of the cloth substrate and subjecting the applied substrate to hot pressing in a mold capable of forming the integral molding. When applied as dynamic speakers, the integral molding exhibits a broad frequency band, low distortion rates and high sound quality. The stiffness difference between the diaphragm and edge portions may be created by using one type of thermoplastic resin which is applied to the diaphragm and edge portions in different amounts.

Diaphragm-edge integral moldings for speakers, acoustic transducers

A diaphragm for speakers comprises a self-support, shaped body including a tightly woven synthetic polymer fiber cloth substrate which has at least a diaphragm portion and edge portion shaped integrally with and extending from the diaphragm portion. The diaphragm portion of the cloth substrate had a polymer resin at least partially impregnated therein and the edge portion has a relatively flexible polymer material at least partially impregnated therein so that the edge portion is lower in stiffness than the diaphragm portion. The diaphragm-edge integral molding is fabricated by applying the respective types of polymers to the diaphragm and edge portions of the cloth substrate and subjecting the applied substrate to hot pressing in a mold capable of forming the integral molding. When applied as dynamic speakers, the integral molding exhibits a broad frequency band, low distortion rates and high sound quality. The stiffness difference between the diaphragm and edge portions may be created by using one type of thermoplastic resin which is applied to the diaphragm and edge portions in different amounts.

Diaphragm-edge integral moldings for speakers and acoustic transducers

A speaker which is thin but which is capable of providing high-fidelity reproduction and ensuring a suitable level of sound pressure even when it is brought close to a wall. A closed chamber is formed behind one part of a disphragm mounted in an enclosure, and an open chamber is formed behind another part of the diaphragm. At least one voice coil driver unit is connected to the diaphragm. The phase difference between sounds radiated from the front and rear surfaces of the diaphragm is increased as large as possible by using an acoustic duct for the sound radiated through the open chamber, thereby minimizing cancellation of sounds and improving the sound pressure level.

Thin speaker having an enclosure with an open portion and a closed

A sound reproducing apparatus for use in a vehicle having a speaker system constituted by at least one acoustic duct and a speaker unit disposed at a throat of the acoustic duct, an opening formed at the other end of the acoustic duct facing the passenger compartment of a vehicle. The apparatus is arranged such that, F0 and Fs are substantially equal to each other. Where Fs is the lowest frequency in a frequency range within which the imaginary part of the acoustic impedance at the sound radiating surface of the speaker system in the direction of the space within the passsenger compartment is zero and F0 is the low-range resonance frequency of the speaker system itself in the free space.

Sound reproducing apparatus for use in vehicle

A diaphragm for loudspeakers comprises chitin as a natural high polymeric material having a large value of Young's modulus and kraft pulp having large mechanical internal loss. Therefore, the deformation and the partial vibrations of the diaphragm during diaphragm operation do not come out due to the use of the chitin, because the flexural rigidity of the diaphragm is considerably large. Mechanical internal loss is also large owing to the use of the kraft pulp. As a result, it is possible to obtain a loudspeaker which has little fluctuation in frequency response, and which provides a superior sound pressure-frequency response, a superior distortion factor and a superior phase response.

Diaphragm for loudspeakers

A speaker diaphragm comprises a composite film prepared by combining a reinforcing material such as a mica, a needle or fiber filler, or talc, with a polybisphenol phthalate resin consisting of an aromatic dicarboxylic acid and a dihydric phenol.

Diaphragm for loudspeaker

An acoustic diaphragm for speakers having a sandwich structure constituted by a core material comprising an elongated web material bent to have a plurality of radial projections, and upper and lower surface members adhered to the upper and lower edges of the core member, as well as a method of producing the same. The acoustic diaphragm of the invention has a reduced weight while exhibiting a large flexural rigidity so that the nodal line during the resonance vibration can have a circular form which in turn offers a circular form of nodal line and increased speaker power. Also, the method of producing the invention permits easy fabrication of the acoustic diaphragm having a sandwich structure.

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Hyogo, Japan

Kousaku Murata