| 摘要 |
1,001,809. 809. Photo-electric pressure transducers. AMERICAN OPTICAL CO. March 10, 1964 [April 19, 1963], No. 10022/64. Heading G1A. The invention relates to a photo-electric . pressure transducer comprising a catheter measuring head dimensioned so as to be suitable for insertion into the cardiovascular system to enable the blood pressure at required points therein to be investigated. The apparatus is not only capable of following pressure variations at heart-beat frequencies but also at audio frequencies so that the sound of an internal organ functioning can be monitored at close range. The apparatus consists essentially of a measuring head including a diaphragm 48 which has one side open to receive the pressures to be measured and the other side of which receives light from strands in an optical fibre bundle 24 and reflects the light to a greater or lesser extent according to pressure into other fibres in the bundle. The fibre bundle is made flexible for exploratory purposes and close to the external measuring part of the apparatus is split in junction box 14 into a first group 24.2 which receives light from source 18 and a second group 24.3 light from which falls on a photo-cell 20. The measuring part of the apparatus is preferably arranged as shown in Fig. 5. Lamp 18, fed from a regulated power supply is there shown as feeding into the fibre bundle 12.2 through a half-silvered mirror 72 which directs a reference level radiation beam to photo-cell 76. The instantaneous amplitudes of the signals from the cells 20 and 76 are compared in unit 82 and after amplification separated by low and high pass filters into components having frequencies lower than 60 c.p.s. and higher audible frequencies. The lower frequency signal is modulated in accordance with fluid pressure variations at the measuring head position whilst the other carries any sounds picked up. The outputs may be fed to recorders, oscilloscopes or loudspeakers. |
