Surgery – Truss – Pad
Patent
1988-06-15
1990-03-06
Jaworski, Francis
Surgery
Truss
Pad
422 681, 73 53, 436806, A61B 800
Patent
active
049057014
ABSTRACT:
In analysis, particularly for medical diagnostics, material can be selectively bound to the surface of a piezoelectric crystal by a reagent. The amount of material so bound affects the speed of propagation of an acoustic wave launched and received on the crystal surface by respective electrode pairs. Previously the crystal was used as a resonant element in an oscillator controlling the frequency of oscillation and so indicating the amount of bound material. However, the oscillator was either unstable or the range of bound masses too small to be of practical use. In the present invention delay between launch and reception of the acoustic wave provides a control signal for a voltage controlled oscillator. A much more stable system can therefore be constructed with a wide working range and high stability since the crystal is no longer the resonant element. Much greater sensitivity is also possible since the oscillator frequency may be greatly increased. A control signal representative of delay may be produced by a phase comparator comparing the phase of two input signals: one direct from the oscillator, and one from the reception of an acoustic wave on the crystal surface launched using a signal from the oscillator. The signal to the crystal may be modulated using a low frequency oscillator before it reaches the crystal to aid the oscillator in following frequency changes due to changing crystal surface conditions and the resulting signal may be summed with the output of a resonance oscillator before application to the crystal to aid the oscillator in initially settling to a stable frequency.
REFERENCES:
patent: 4314821 (1982-02-01), Rice
patent: 4361026 (1982-11-01), Muller et al.
patent: 4398115 (1983-08-01), Gagnepain et al.
patent: 4691714 (1987-09-01), Wong et al.
patent: 4735906 (1988-04-01), Bastiaans
"Palladium-Surface Acoustic Wave Interaction for Hydrogen Detection", by A. d'Amico, Appl. Phys. Lett. 41 (3), 1st Aug. 1982.
"Piezoelectric Crystals as Detectors in Liquid Chromatography", by P. L. Konash and G. J. Bastiaans, Anal. Chem., 1980, 52, pp. 1929-1931.
"Liquid-Phase Piezoelectric and Acoustic Transmission Studies on Interfacial Immuno Chemistry", by M. Thompson, C. L. Arthur and G. K. Dhaliwal, Anal. Chem., 1986, 58, pp. 1206-1209.
"Surface Acoustic Wave Probe for Analysis. I. Introduction and Instrument Description", by H. Wohltjen and R. Dessy, Analytical Chemistry, vol. 51, No. 9. Aug. 1979, pp. 1458-1464.
Jaworski Francis
National Research Development Corporation
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