Electromagnetic bipolar loud speaker

• US 4,081,627 A
• Filed: 12/27/1976
• Issued: 03/28/1978
• Est. Priority Date: 12/27/1976
• Status: Expired due to Term

• Current Assignee: Audio Research Corp. (McIntosh Group, Inc.)
• Original Assignee: Audio Research Corp. (McIntosh Group, Inc.)
• Inventors: Crist, Scott D.
• Primary Examiner(s): Stellar, George G.
• Application Number:
  US05/754,510
• Time in Patent Office: 456 Days
• Field of Search: 179/115.5 PV
• US Class Current: 381/408
• CPC Class Codes: H04R 7/06 comprising a plurality of sections or layers
• CPC Class Codes: H04R 9/047 in which the windings of the moving coil lay in the same plane

Abstract

An electromagnetic bipolar loud speaker of the planar type utilizing a vibratable diaphragm having conductors positioned thereon and uniformly distributed over the vibratable area of the diaphragm to interact with a unidirectional, homogeneous magnetic field generated by a coil surrounding the diaphragm. The loud speaker may be made of a number of diaphragms with different sized vibratable areas and with the same conductor orientation thereon with respect to the supporting frame and energizing magnetic field to cover the wide range of frequency responses.

Claims

1. An electromagnetic current sheet transducer comprising:

a taut diaphragm of dielectrical material having a vibratable area positioned on a planar frame;

a plurality of conductors positioned on the vibratable area of the diaphragm in spaced parallel relationship;

an electrical bus positioned on the planar frame displaced from said diaphragm;

a plurality of connector means for individually connecting the conductive strips to said bus; and

a single magnetic field means generating a uniform magnetic field around the surface of the diaphragm and over the surface of the diaphragm normal to the direction of current flow through the conductors on the diaphragm.

2. An electromagnetic current sheet transducer of claim 1 in which the magnetic field generating means being a coil wound on said planar frame with an opening therein in which the diaphragm is positioned and through which portions of said connector means extend.

3. The electromagnetic current sheet transducer of claim 2 in which the conductors are strips of conductive material deposited on the diaphragm.

4. The electromagnetic current sheet transducer of claim 3 in which the connector means connecting the conductor strips are connected to the ends of each conductor strip to connect one strip to another through said bus to cause the current flow in the conductors in the same direction.

5. A sound generating transducer comprising a planar frame, a plurality of flexible diaphragms each having a vibratable area positioned in the planar frame, conductor means affixed on each of the diaphragms to receive audio frequency electric signals, connector means including electrical bus means positioned on said frame and connected to the conductor means on each of said diaphragms to cause current flow in the conductor means only in the same direction across the vibratable area of each diaphragm, and a single magnetic field generating means surrounding said frame and providing a uniform homogeneous magnetic field normal to the direction of current flow of the conductors in each of the diaphragms and uniformly over and around the vibratable areas of the diaphragm, said uniform homogenous magnetic field surrounding the diaphragm being generated by a coil wound around the diaphragm and circling the same with turns of the coil extending generally parallel to the conductor means positioned on the diaphragm.

6. The electromagnetic current sheet transducer of claim 5 in which the connector means connecting the conductor strips include bus means connecting certain of said conductor strips at the extremities with additional connecting means positioned outside the magnetic field connecting the buses in a series relationship.

7. The electromagnetic current sheet transducer of claim 5 in which the conductor means positioned on the diaphragm are strips of highly conductive material deposited on the diaphragm is spaced parallel relationship.

8. The electromagnetic current sheet transducer of claim 5 in which the conductors on the diaphragms are substantially uniformly spaced from the magnetic field means.

9. The electromagnetic current sheet transducer of claim 5 in which the conductors positioned on the diaphragm have the same cross sectional dimension and the same length dimension in the vibratable area.

10. The electromagnetic current sheet transducer of claim 5 in which the diaphragm is a thin layer of polyethelene-terphthalate material.