Patents by Inventor Johannes J. M. Kamphues

Johannes J. M. Kamphues has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4847908
    Abstract: An electrodynamic loudspeaker (1) has a diaphragm comprising a central part (2) and a peripheral part (3), and a voice-coil device (9, 10) coupled to the central part (2). The surface ratio S.sub.2 /S.sub.1 complies with the relationship 0.5.ltoreq.S.sub.2 /S.sub.1 .ltoreq.6, where S.sub.1 and S.sub.2 are the surface areas of the central part (2) and the peripheral part (3) respectively. The mass ratio m.sub.2 /m.sub.1 complies with the relationship 0.5.ltoreq.m.sub.2 /m.sub.1 .ltoreq.8 where m.sub.1 and m.sub.2 are the mass of the central part (2) and the voice-coil device (9, 10) and the mass of the peripheral part (3) respectively. Further, the stiffness imposed on the diaphragm by the space (6, 6') defined by the diaphragm (2, 3) and the chassis (4) and/or the magnet system (7) is smaller than the stiffness of the diaphragm itself. Thus it is possible to derive a car loudspeaker which has a specific dip in its frequency response characteristic P (FIG. 2a), measured in an anechoic room.
    Type: Grant
    Filed: September 28, 1987
    Date of Patent: July 11, 1989
    Assignee: U.S. Philips Corp.
    Inventors: Joris A. M. Nieuwendijk, Johannes W. T. Bax, Johannes J. M. Kamphues, Franciscus C. M. de Haas