A piezoelectric audio transducer adapted to produce a sound output when a vibrator which is formed by bonding a piezoelectric element to a metallic diaphragm is electrified, wherein the audio transducer is formed by securely supporting the outer periphery of the vibrator on an acoustic casing, and a fixing part to be fixed to a mounting body is provided on the audio transducer and is connected to the casing with an elastic body interposed therebetween so as to thereby enable the casing which is fixed to the mounting body to vibrate integrally with the vibrator when said vibrator is vibrated.

A secondary for a linear motor includes a body comprised of at least one secondary member for defining a guideway for a rotor of the linear motor and a cover including magnetizable material for the guideway. Disposed between the secondary member and the cover is an anti-skid layer to secure the cover against displacement.

A thin, high-fidelity piezoelectric loudspeaker is disclosed which comprises: (a) first and second metal discs that are spaced apart; (b) at least one damping disc sandwiched between the first and second metal discs; (c) first piezoelectric disc affixed to the first metal disc on the opposite side of the damping disc; and (d) second piezoelectric disc affixed to the second metal disc on the opposite of the damping disc. The metal discs and the piezoelectric discs are electrically connected, respectively, via varnished wires. These improved piezoelectric loudspeakers can be most advantageously used in portable electronic devices such as notebook personal computers, electronic dictionaries, personal digital assistants, electronic Rolodexes.RTM., etc, where space, especially thickness, is often at a premium and high-fidelity, miniature-sized speakers are highly desired.

The case has an opening and a wall section with a hole provided on the wall section and the wall section forms an inner space. The case also has a recessed area surrounding the hole. The piezoelectric diaphragm is supported around its periphery on top of the case so that an enclosure, including the hole, is formed within the inner space. An acoustic resistance sheet is bonded on to the wall section with the adhesive that is filled into the recessed area to close off the hole. With this structure, defective damping caused by seeping of the adhesive is prevented.

A reduced-size speaker for generating sound waves in wide low frequency audio region includes a cylindrical main body which is open at the top and bottom surfaces, a top lid being provided on the top surface of the main body and a circular ring-shaped base, which has a hole in its center, being provided on the bottom surface of the main body. A circular sound pipe is provided approximately in the center of the top lid and extends from the upper surface of the main body through the inside of the main body. A disc-like film is provided over the opening of the hole of the base, which is located at the outer side with respect to the main body, the disc-like film being held between the base and a circular ring-shaped bottom lid. A disc-like sound generator is provided in the opening of the hole of the base, which is located at the inner side with respect to the main body, with a circular ring-shaped damper provided in between. A plurality of supporting members are attached to the bottom lid in order to mount the speaker on a mounting surface.