| 摘要 |
<p>A vibration detector for a seismic system having a weight member, a support frame, at least two weight supporting members, each being fixed to the weight member at one end thereof and being substantially fixed to the support frame at one portion thereof, and a member for substantially fixing one portion to the support frame. The weight member is vibratively supported by the tension of the supporting members. At least a part of one of the supporting members is formed by a piezoelectric polymeric substance having a pair of vibration detecting electrodes, the part being at a position between the fixed end and one substantially fixed portion of the supporting member. Suitable piezoelectric polymeric substances include polyvinylidene fluoride type substances, for example of vinylidene fluoride homopolymer, a copolymer of vinylidene fluoride and at least one comonomer copolymerizable therewith, for example a halogenoalkene such as vinyl fluoride, tetrafluoroethylene or chlorotrifluoroethylene, the copolymer containing more than 50 mol% of vinylidene fluoride units in the main polymer chain, or a composition consisting predominantly of such a homopolymer and/or copolymer and also containing a compatible resin, for example poly (methyl methacrylate) or poly (methyl acrylate). Other materials may also be included in the composition.</p> |
