| 摘要 |
518,636. Diaphragms. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE. Aug. 30, 1938, No. 25440. Convention date, Aug. 30, 1937. [Class 40 (iv)] [Also in Group VIII] An acoustic diaphragm comprises a base member of mesh, the size of the apertures 1 in which increases progressively from the centre to the outer edge. The apertures are filled with a light varnish material or foil of a cellulose derivative. The mesh may be composed of a light material of high internal friction such as aluminium or of moulded material such as celluloid. Specification 306,193, [Class 40 (iv)], is referred to. |
