Loudspeaker having a voice coil and a piezoelectric feedback transducer
AssigneeU.S. Philips Corporation
InventorGuido Odilon Maurits D'Hoogh
Life of this patent
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Abstract
Loudspeaker, in particular low-note loudspeaker, provided with a cone-shaped diaphragm having a coil form on which in addition to the voice coil is mounted a piezoelectric transducer in the form of a thin plate capable of pivotal movement. The output voltage of the transducer is degeneratively fed back to the input of an associated amplifier. The plate preferably is rectangular and suspended in rubber mounts along two opposed edges. The mounts form part of a mounting board provided with printed wiring on which an electronic transformation circuit is arranged. A shallow cup in which the mounting board is accommodated ensures that the piezoelectric plate is separated in an airtight manner from the coil form.
Claims10
A loudspeaker comprising, a cone-shaped vibratory diaphragm having an inner portion secured to a coil form, a voice coil mounted on the coil form, means including the voice coil for vibrating the coil form and diaphragm, a piezoelectric transducer mounted on the coil form and comprising a thin plate of piezoelectric material having two opposed edges hingedly connected to the coil form and situated within the circumference of said voice coil and with its major surfaces lying in a plane substantially normal to the axis of the voice coil, and means for degeneratively coupling the output voltage of the piezoelectric transducer to an input of an amplifier adapted to drive the voice coil.
A loudspeaker comprising, a cone-shaped vibratory diaphragm having an inner portion secured to a coil form and an outer portion attached to a support member, a voice coil attached to the coil form for vibrating the coil form and the attached diaphragm, a transducer comprising a plate of piezoelectric material, means for mounting said piezoelectric plate on the coil form in non-cantilevered fashion within the circumference of said voice coil and with its major surfaces lying in a plane substantially normal to the axis of the voice coil so as to allow pivotal movement of the plate, and means for coupling the output voltage of the transducer to an input of an amplifier adapted to drive said coil.
Dependencies are inferred from the claim text.