US 9,804,126 B2Granted

Apparatus and method for improved acoustical transformation

AssigneeVeeco Instruments Inc.

InventorsRaymond C. Logue, Don N. Sirota, William E. Quinn, Owan C. Watkins, Maria D. Ferreira, Wei Zhang

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Abstract

An acoustical transformer having a last matching section that includes a protective barrier of low permeability. The protective barrier is in contact with a test medium. In one embodiment, the protective barrier comprises one or more low permeability layers, such as a metallic foil or metallic coating(s) disposed on a low impedance layer such as polyimide, so that the low impedance layer and the protective barrier constitute the last matching section of the acoustical transformer. In other embodiments, the protective barrier comprises a fluoropolymer. A method for determining the thicknesses of the various layers of the acoustical transformer for enhanced performance is also disclosed.

Claims27

Dependent claims

An apparatus for acoustically determining a property of a test medium, comprising:

a chamber for containment of a test medium, said chamber having at least a first side and an inlet for said test medium;
a first acoustical transformer operatively coupled with the first side of said chamber and configured to at least one of transmit and receive a pulse of acoustical energy with respect to said test medium;
and
an acoustical element operatively coupled with said first acoustical transformer,
wherein said first acoustical transformer includes:
a base matching section, a first surface of said base matching section being in contact with said acoustical element;
a last matching section operatively coupled with said base matching section and having an exposed face adapted for contact with said test medium, said last matching section including a protective barrier having a first predetermined thickness disposed on a low impedance layer having a second predetermined thickness to form at least part of said exposed face, wherein the first and second predetermined thicknesses are configured to cooperate to produce a predicted transfer function of the apparatus that is within 70% of a predicted transfer function of an apparatus without a protective barrier, and tailor the resonance frequency of the last matching section such that the highest resonance frequency is limited to below 1.2fC and the lowest resonance frequency is limited to above 0.8fC, wherein fC is the center operating frequency, thereby reducing drift of the first acoustical transformer over time by inhibiting an accrual of a portion of the test medium on the last matching section, while reducing distortion of the at least one of transmitting and receiving of the pulse of acoustical energy caused by the protective barrier.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/705,650Filed 5 Dec 2012 · us provisional application
Priority: 4 Sep 2012
Published: US 2014/0060153 A16 Mar 2014
Granted: 31 Oct 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G01N 29/00
Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic
G01N 29/036
Analysing fluids: by measuring frequency or resonance of acoustic waves
G01N 29/222
Details , e.g. general constructional or apparatus details: constructional or flow details for analysing fluids
G01N 29/2437
Probes: piezoelectric probes