Abstract: An electroacoustic transducer comprising a magnetic circuit of a magnetically conductive material with a pair of opposed surfaces defining a gap there between, the magnetic circuit comprising one magnet. The magnet can either be positioned in the centre of the magnetically conductive material so as to form two gaps. In an alternative embodiment the magnet is attached to the magnetic conductive material forming only one gap. The transducer further comprises a diaphragm and a coil system having electrically conducting paths fastened to the diaphragm. The coil system has portions of its paths situated in the gap. The transducer may be supplied with an additional diaphragm and coil system positioned on the opposite side of the magnetic circuit. In a preferred embodiment the transducer is rectangular. The transducer is suited for integration into miniature components such as mobile communication equipment and hearing aids.

Abstract: The present invention relates to a mobile handset comprising a handset housing comprising a front and a back cover, display means being visible from the front cover side of the handset housing, the display means being adapted to provide visual information to a user of the mobile handset. The mobile handset further comprises a plurality of loudspeakers being adapted to generate audio signals, wherein each of the plurality of loudspeakers comprises a magnetic circuit comprising a magnet, the magnetic circuit having at least one gap defined between two opposed and substantially parallel surfaces of the magnetic circuit. The magnet of the magnetic circuit causes a magnetic field to exist across the at least one gap. The magnetic circuit is so arranged that it defines magnetic return paths completely encircling the gap.

Abstract: A diaphragm for an electroacoustic transducer, the diaphragm comprising a flexible sheet comprising first and second sheet sections, each of the first and second sheet sections defining a substantially plane surface, and one or more electrically conductive coils, wherein each of the one or more coils is defined as an electrically conductive path on the substantially plane surfaces of first and second sheet sections so as to form, for each coil, first and second coil sections, respectively. The flexible diaphragm may be implemented using a single-sided or a double-sided flexprint. An integrated diaphragm and coil system may be formed by a monolithic flexprint. The diaphragm may be used for microphones or loudspeakers.

Abstract: A miniature speaker having built-in electronic components for providing a feedback signal for dynamically adjusting acoustical parameters of the miniature speaker. The miniature speaker includes in the preferred embodiment a housing, a magnetic circuit, a coil, a diaphragm, a sensor, and an electronic circuit. The sensor is formed by the metallized portion of the diaphragm and the metallized portion of the housing cover. The two metallized portions form a plate capacitor, and as the diaphragm vibrates, the capacitance of the plate capacitor changes. These changes are converted into a feedback signal which is combined with the input audio signal in an electronic circuit mounted directly on the diaphragm and which drives the speaker while adjusting acoustical parameters, such as resonance, distortion, and sensitivity. The feedback signal can also be used to protect the active components of the miniature speaker against mechanical stress, thereby prolonging the lifetime of the speaker.

Abstract: The present invention relates to an electro-acoustic transducer suitable for applications within mobile communication equipment and hearing aids. The transducer comprises two diaphragms positioned on opposite sides of a magnetic circuit having two magnetic gaps. When used as a microphone the transducer is substantially insensitive to vibrations, and when used as a speaker the transducer generates only very low vibration levels. The magnetic circuit has a number of advantages compared to conventional transducers with circular magnetic. The transducer can be made lightweight and with very compact dimensions compared to conventional designs. In a preferred embodiment the diaphragms are rectangular. The transducer may additionally be used as a vibration generator for silent alarm signals.

Abstract: An electroacoustic transducer comprising a magnetic circuit of a magnetically conductive material with a pair of opposed surfaces defining a gap therebetween, the magnetic circuit comprising a magnet inducing a magnetic field in the gap, the magnet having a surface constituting one of the opposed surfaces. The magnetic circuit further comprises a diaphragm and a coil having electrically conducting paths secured to the diaphragm. The coil has portions of its paths situated in the gap.