Antonelli, Terry & Wands
Loudspeaker structure and system
 In a planar loudspeaker structure comprising planar membrane for forming a diaphragm on which a voice coil of a conductor pattern is formed, and a magnetic circuit for supplying a DC magnetic flux which crosses the voice coil, the conductor pattern includes first and second zigzag conductor pattern portions which are juxtaposed on substantially the entire area of the membrane and connected in series. Opposite ends of the series connection of the first and second conductor pattern portions are respectively connected to first and second terminals for receiving a low-band component of an input audio signal. A high-band component of the input signal is applied to a third terminal connected to a junction between the first and second conductor pattern portions and supplied only to the second conductor pattern portion. The voice coil having the first and second zigzag conductor pattern portions is driven in a multi-drive fashion by driving forces which are weighted relative to each other so as to provide a flat sound pressure/frequency characteristic and a flat electrical impedance characteristic. In addition, the radiation area of the diaphragm is partly weighted by the disposition of the first and second zigzag conductor pattern portions so that the entirety of the membrane is vibrated in a low band and a portion of the membrane is vibrated in a high band, thereby improving the directivity characteristic. 
Hitachi, Ltd.
H
H04R
inventional
Tohru Yoshio Makoto
Mori Ariki Kohashi