| 摘要 |
1,174,909. Piezoelectric elements. NIPPON ELECTRIC CO. Ltd. 21 Dec., 1966 [21 Dec., 1965], No. 57094/66. Heading H1E. [Also in Division C7] A shear-mode piezoelectric transducer is produced by vacuum deposition at oblique incidence of an electrode and subsequently of a layer of piezoelectric material. The electrode 13, of, e.g. aluminium, is first deposited upon a substrate 11 forming an acoustic load. This may be made of, e.g. quartz, glass, rock crystal, ruby or cadmium sulphide. The piezoelectric layer 14 may consist of a Group II-VI compound, e.g. CdS. The angles a, b at which the crystals lie in the respective layers 13, 14 may be the same, e.g. 60 degrees, or may differ by several degrees. An outer electrode 15, of, e.g. gold, is deposited by evaporation. Because of the oblique incidence of the C-axes of the piezoelectric crystals both longitudinal and shear modes are generated, but the former is greatly attenuated. The Specification gives details of the methods used for evaporation (see Division C7). |
