| 摘要 |
<p>1532292 Diaphragms and stylus arms PIONEER ELECTRONIC CORP 28 May 1976 [30 May 1975] 22382/76 Heading H4J The diaphragm of a loudspeaker or microphone or the cantilever stylus arm of a gramophone pickup is formed of a substrate of titanium, carbon, carbonized plastics, carbon fibre filled plastics, aluminium or beryllium into at least a zone of which is diffused boron, nitrogen or silicon. By diffusion is meant both physical diffusion and chemical reaction occurring during the physical diffusion. A combination of Ti and B, C and B or C and Si is preferred since this optimizes the ratio of Young's modulus to density and assists in eliminating unwanted resonances. The particle diameter is not more than 50Á. Where Ti and B are used, preferably carbon black and sodium carbonate are added to the B to prevent oxidation of the Ti during the heating step used to effect diffusion. A dome diaphragm may be provided with a diffusion layer only at the periphery (Fig. 9B) to enhance the rigidity of the support portion. A second, inner, coaxial annular diffusion zone may be provided as well (Fig. 10A, not shown). Alternatively the dome diaphragm may have a single central diffusion zone (Fig. 10B, not shown) or a circular array of circular diffusion zones (Fig. 10C, not shown) or a radial array of diffusion zones (Fig. 10D, not shown). Desirable local vibrations may thereby be induced while undesirable vibrations are reduced. In another arrangement a non-coaxial, non- symmetrical elliptical diffusion zone (Fig. 10E, not shown) is formed on a dome diaphragm thereby substantially eliminating the generation of standing waves. A cantiliver stylus arm (Fig. 14), on one end of which a magnet (not shown) is secured, is formed with spaced diffusion zones. Alternatively a diffusion layer is formed on the outer face of the stylus arm (Fig. 11, not shown) on the inner and outer faces of the stylus arm (Fig. 12, not shown) or at the end of the stylus arm adjacent the magnet (Fig. 13, not shown).</p> |
