Patent EP0048434A1 successfully refreshed from Google Patents.
EP0048434A1
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Electro acoustic planar transducer
Assignee: Electro Magnetic Corp
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Filing: 1981-09-15
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Granted: —
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Expires: 2001-09-15
Abstract
Abstract An electro-acoustic transducer using thin, light-weight, planar diaphragms (13, 14) driven by strategically located, coil driven, high-energy, permanent magnets (41). A framework (12) maintains the diaphragms (13, 14) in substantially co-planar relationship a predetermined distance from and parallel to a rear support wall (16). The diaphragms (13, 14) include at least one hinged woofer diaphragm (13) and a foam-supported tweeter diaphragm (14). The small, high energy movable permanent magnets (41) are attached to the rear surface of each movable diaphragm (13, 14). Cooperating with each movable magnet (41) is a respective, stationary electromagnetic coil (29) with a cross-over network directing the incoming signal to the appropriate coils, thereby placing the magnets (41) and attached diaphragms (13, 14) into cooperating fore and aft motion. The frontal acoustical waves produced by each woofer constructively interfere to augment low frequency response. The tweeter construction provides wide frontal dispersion of high frequency acoustical waves. Woofer backwaves are attenuated before emerging along the rear support wall and the tweeter backwave is vented into a rear isolative chamber.
Inventors
- 👤 Stanley L. Marquiss
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 22:01
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/22; H04R1/24; H04R11/00; H04R11/02
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
73 words
An electro-acoustic planar transducer comprising: a substantially planar frame having a front side and a rear side; a planar woofer diaphragm; means for mounting said woofer diaphragm on and parallel to said frame for alternating movement toward and away from said front side and said rear side, and cooperating coil and magnet means interposed between said frame and said woofer diaphragm for driving said woofer diaphragm in response to an impressed electrical signal.
Claim 2
Dependent Claim
73 words
An electro-acoustic planar transducer comprising: a substantially planar frame having a front side and a rear side; a planar woofer diaphragm; means for mounting said woofer diaphragm on and parallel to said frame for alternating movement toward and away from said front side and said rear side, and cooperating coil and magnet means interposed between said frame and said woofer diaphragm for driving said woofer diaphragm in response to an impressed electrical signal.
Claim 3
Dependent Claim
62 words
A transducer as in claim 1, including a planar tweeter diaphragm, means for mounting said tweeter diaphragm on and parallel to said frame for alternating movement toward and away from said front side and said rear side, and cooperating coil and magnet means.interposed between said frame and said tweeter diaphragm for driving said tweeter diaphragm in response to said impressed electrical signal.
Claim 4
Dependent Claim
56 words
A transducer as in claim l,in which said cooperating coil and magnet means includes a plurality of aligned drive coils mounted on said frame with the coil axis normal to said frame, and a plurality of high energy magnets mounted on said diaphragm for coaxial fore and aft movement of said magnets relative to said coils.
Claim 5
Dependent Claim
79 words
A transducer as in claim 1, 2 or 3, including means for mounting said frame on a vertical planar surface so that said rear side faces toward the planar surface and said front side faces away from the planar surface, and sound absorptive means mounted on said frame and interposed between at least one predetermined portion of said. woofer diaphragm and said planar surface for attenuating the acoustic back waves generated by said predetermined portion of said woofer diaphragm.
Claim 6
Dependent Claim
62 words
A transducer as in claim 1, 2, 3 or 4, wherein said planar woofer diaphragm is rectangular and, with the long dimension of said woofer diaphragm in vertical attitude, has one proximal vertical edge mounted on said frame, the opposite distal vertical edge of said woofer diaphragm being movable and partaking in excursions of intermediate extent as said woofer diaphragm is driven.
Claim 7
Dependent Claim
24 words
A transcuder as in claim 2 in which said planar twe " eter diaphragm is straddled by a pair of said planar woofer diaphragms,
Claim 8
Dependent Claim
43 words
A transducer assembly comprising a pair of transducers as in claim 2, in which said woofer and said tweeter diaphragms are arranged in mirror symmetry so that said tweeter diaphragms are adjacent each other and said woofer diaphragms are remote from each other.
Claim 9
Dependent Claim
179 words
A transducer as in claim 1, including a pair of said planar woofer diaphragms which are lightweight and substantially rigid, a lightweight substantially rigid, planar tweeter diaphragm; said rear side being adapted to face toward a planar surface, said mounting means mounting said woofer diaphragms and said tweeter diaphragm on said frame in co-planar relation a predetermined distance from the planar surface of predetermined width to form a channel around the periphery of said diaphragms, said woofer diaphragms being attached to said frame at their adjacent proximal edges allowing unimpeded front and rear motion of their respective distal edges, and said coil and magnet means.being mounted on said frame and interconnected to said woofer diaphragms a predetermined distance from said adjacent proximal edges of said woofer diaphragms for placing said woofer diaphragms into front and rear motion about their respective proximal edges in response to an electrical drive signal, said coil and magnet means being further interconnected to said tweeter diaphragm for placing said tweeter diaphragm into front and rear motion in accordance with a supplied electrical drive signal.
Claim 10
Dependent Claim
63 words
9 . A transducer as in claim 8, including a pair of pieces of highly compliant material interposed between and attached to said frame and said woofer diaphragms and a piece of highly compliant material interposed between and attached to said frame and said tweeter diaphragm, said material being yieldable to permit fore and aft motion of said diaphragms relative to said frame.
Claim 11
Dependent Claim
65 words
A transducer as in claim 8 or 9, in which said peripheral channel underlies the distal edge portion of each of said woofer diaphragms and acoustically vents the backwaves generated thereby in a lateral direction, the intent of said predetermined channel width being selected so that the laterally vented backwave and the frontal wave generated by said woofer diaphragm advance in substantially perfect phase relationship.
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