Matsushita has developed an ultra-slim speaker unit called ‘Sound Slim’ that incorporates a new sandwich-type magnetic circuit making the speaker unit slimmer while having very low magnetic leakage.
Conventional speaker units use a cylindrical voice coil inserted in the magnetic gap, making it impossible to realise a thinner speaker. In addition, magnetic leakage from this type of speaker unit can damage cards that contain data recorded in magnetic stripe if the unit is brought close to the cards. As a result, a cancelling magnet or a magnetic shield is necessary as an anti-magnetic measure.
The ‘Sound Slim’ speaker unit uses a magnetic circuit which produces horizontal magnetic flux in the repelling magnetic field formed by two magnets with the same polarity arranged vertically in parallel to each other.
As a result, the developed speaker unit is approximately 3/4 the thickness and approximately 1/2 the width of the conventional speaker. Also, the magnetic circuit of the developed speaker has very low magnetic flux leakage. Therefore, no anti-magnetic measure is necessary to protect cards that contain data recorded in magnetic strips from magnetic disturbance.
A rigid diaphragm and the flat, oblong voice coil suppresses the diaphragm’s vibration mode that has an adverse influence on the quality of reproduced sound.
The ‘Sound Slim’ speaker unit will be marketed by Matsushita Electronic Components at the end of 2002.