(19)
(11) EP 0 398 257 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
24.02.1993 Bulletin 1993/08

(43) Date of publication A2:
22.11.1990 Bulletin 1990/47

(21) Application number: 90109149.6

(22) Date of filing: 15.05.1990
(51) International Patent Classification (IPC)5: H04R 7/02
(84) Designated Contracting States:
DE GB

(30) Priority: 18.05.1989 JP 125521/89
01.06.1989 JP 139638/89

(71) Applicant: YAMAHA CORPORATION
Hamamatsu-shi Shizuoka-ken (JP)

(72) Inventors:
  • Mochizuki, Osamu
    Hamamatsu-shi, Shizuoka-ken (JP)
  • Hoshi, Toshiharu
    Hamamatsu-shi, Shizuoka-ken (JP)

(74) Representative: Herrmann-Trentepohl, Werner, Dipl.-Ing. et al
Patentanwälte Herrmann-Trentepohl, Kirschner, Grosse, Bockhorni & Partner Forstenrieder Allee 59
81476 München
81476 München (DE)


(56) References cited: : 
   
       


    (54) A speaker diaphragm


    (57) In a laminated construction of a speaker diaphragm including one or more diamond phase base layers, one or more silicon car­bide or beryllium predominant layers are combined with the diamond phase base layer as a substitute for conventional alumina or silicon nitride layers. High sound transmission speed in­herent to silicon carbide and beryllium much improves frequency characteristics in particular in the treble range.







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