(19)
(11) EP 0 262 406 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
31.08.1988 Bulletin 1988/35

(43) Date of publication A2:
06.04.1988 Bulletin 1988/14

(21) Application number: 87112525

(22) Date of filing: 16.06.1983
(84) Designated Contracting States:
AT BE CH DE FR GB LI LU NL SE

(30) Priority: 17.06.1982 US 389423

(71) Applicant: LARSON, David A.
 ()

(72) Inventors:
  • Larson, David A.
     ()
  • Shumaker. Daniel A.
     ()

   


(54) Electro-acoustic transducer with diaphragm and blank therefor


(57) This disclosure relates to an electro-acoustic transducer with a diaphragm (12) consisting of a corrugated sheet (34A) and a thin flat shet (32). The corrugated sheet has a plurality of conductors (36, 39) in rearwardly extending projections (P) and sheet (32) is secured to the front, flat surface (29) of the corrugated sheet (34A). With conventional diaphragms, the corrugations on the sheet are not secured to each other thereby resulting in a flimsy structure with an uneven front surface which prevents sound waves emanating from the surface from being in phase. The front sheet of the diaphragm (12) rigidifies it such that the corrugated sheet (34A) remains even and the projections (P) remain in alignment with the pole pieces (44, 46) of the magnet assembly (14). To obtain good frequency response and the desired impedance, more conductors are necessary than those used in the conventional diaphragms. The conductors (36, 39) in the present invention are deposited on a blank (34) directly opposite each other such that the blank can be readily folded without bowing or being otherwise deformed. Also, as the diaphragm (12) is oscillated, air is forced around the conductors (36, 39) and vented through the gaps in the magnet assembly (14) thereby relieving heat buildup.





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