| 摘要 |
<p>1,259,631. Measuring blood pressure. F. HOFFMANN-LA ROCHE & CO. A.G. 7 Jan., 1969 [11 Jan., 1968], No. 921/69. Heading A5K. [Also in Division H4] Apparatus 11 for biological investigations comprises a plurality of ultrasonic transducer elements mounted in spaced relation along the longitudinal axis of a flexible support so that the apparatus can conform to the curvature of a body area to which it is applied. In the embodiment shown for detecting, by the Doppler shift of reflected ultrasonic energy, the wall motion of an artery constrictable under pressure provided by a pneumatic blood pressure-measuring cuff 33, transducer elements 14, 16 (acting as transmitters) and 13, 15, 17 (acting as receivers) are embedded in a silicone rubber layer 31 with a nylon material or natural fibre cloth backing. This assembly may be strapped to a body member or may be releasably fastened to cuff 33 by means of a pocket, a snap fastener, or a strip fastener of the hook and pile type. The number of transducer elements in the assembly, and their spacing, may be varied according to the size of the body part to which they are applied, and the elements may be used as transceivers, with range-gating of received signals. The assembly may be used also for sensing foetal heart motion. Transducer details. Each transducer element comprises a surface-silvered wafer of barium titanate, lead zirconate titanate, lithium sulphate or quartz, mounted in and coplanar with an aperture in a metal housing which provides R.F. screening and electrical connection to the active surface of the wafer. Silicone rubber in the housing damps backward radiation of acoustic energy from the wafer. The active surface is resin-bonded to a plastics lens which provides acoustic impedance matching and also gives a transmission/ reception beam which is broad in the plane of Fig. 8 but narrow in an orthogonal plane, whereby the Doppler detection of motion of objects outside a region of interest is avoided. The lens is acoustically coupled to the skin tissue by water or mineral oil.</p> |
