| 摘要 |
1,126,588. Heart beat and bloodpressure measurement using ultrasonic doppler-transducers. J. R. RICHARDS. 7 Dec., 1965 [8 Jan., 1965], No. 51815/65. Headings A5K and A5R. [Also in Division H4] An ultrasonic doppler transducer, for use at a frequency above 3 Mc/s and responsive to reflected signals having an amplitude relative to transmitted signals of 3 x 10<SP>-7</SP>, comprises a pair of coaxial, x-cut, quartz crystals 12, 13 which are coated on both sides with gold or silver and which have respective co-axial cables 15, 14 connected to 'the rear sides thereof, a conductive support 11 for the crystals and a low-resistivity, low melting point material 10 which electrically connects the support and screens of the cables so as to electromagnetically screen the circuits of the two crystals from each other. The low m.p. material is applied as a melt during manufacture of the transducer and it may comprise a metal or a conductive epoxy resin. A silicon rubber "diaphragm" 28 protects the crystals and serves to couple the transmitting 13 and receiving 14 crystals whereby acoustic beat signals may be obtained. The leads are connected via helical springs 18, 19 to the electrodes and soldered or pressure connections may be utilised. The rear faces of the crystals and the springs are insulated from the support. The crystals are clamped only at their edges and vibrate in the thickness mode. The following clinical applications are mentioned:- detection of foetal heart beat, blood vessel movement, ballistic cardiography (two such transducers being required), remote monitoring of blood pressure e.g. an astronaut's, and drug testing using chicken embryo. |
