| 摘要 |
1,180,093. Variable resistance transducers. P. HUET. 21 March, 1967 [22 Sept., 1966], No. 13269/67. Heading H4J. [Also in Division G1] A microphone comprises a flexible diaphragm of electrically non-conductive material (e.g. mica, glass, quartz, cellulose acetate or synthetic plastics), on which is deposited an arcuate layer of electrically conductive or semi-conductor material (e.g. bismuth, antimony, tellurium, or germanium). As shown, Fig. 2, there are two arcuate portions of conductive material b1, b2 on one face each extending through approximately 180 degrees and there are identical arcuate layers on the lower face (Fig. 3, not shown) displaced by 90 degrees from those on the upper face. The diaphragm may be peripherally clamped as shown, Fig. 8, and have a damping chamber with outlet 18 below it. In an embodiment for sensing vibrations in the ground as shown, Fig. 7, the diaphragm 1 is backed by a chamber, formed between the diaphragm and a relatively thick steel plate 14, and filled with liquid. This is to prevent puncturing of the diaphragm under high variations in pressure. The conductive layer portions may be connected to form a resistance bridge the unbalance voltage of which corresponds to variations of the resistance of the portions as a result of strain when the diaphragm is subjected to stress. |
