EP0128635A2
Expired / Lapsed
EP
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Measuring non-linear parameter of acoustic medium
Assignee: Fujitsu Ltd
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Filing: 1984-03-09
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Granted: —
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Expires: 2004-03-09
Abstract
Abstract Measurement of a non-linear parameter of an acoustic medium, or its distribution, for example for determining the internal temperature of a sample, is carried out noninvasively. A continuous wave ultrasonic probing beam is radiated through the sample, and a pumping wave which is an ultrasonic pulse wave is superposed on the probing beam. Phase changes of the probing beam caused by the pumping wave are detected. From these phase changes the non-linear parameter (B/A) or (B/A) e is obtained. In ohne case the pumping wave intersects the probing beam. In another case the pumping wave is directed along the probing beam, in the opposite direction.
Inventors
- 👤 Takuso C/O Fujitsu Limited Sato
- 👤 Nobuyuki C/O Fujitsu Limited Ichida
- 👤 Hirohide C/O Fujitsu Limited Miwa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 07:46
CPC Classifications
G; G01; G01K; G01K11/00; G01K11/22; G01H; G01H3/00; G01H3/10; G01H3/12; G01N; G01N2291/00; G01N2291/02; G01N2291/024; G01N2291/02491; G01N2291/028; G01N2291/02881; G01N2291/04; G01N2291/042; G01N2291/0421
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
90 words
A method of measuring a non-linear parameter of an acoustic medium comprising processes: A) providing a probing beam of a probing wave which is a continuous ultrasonic wave propagating through said acoustic medium; B) providing a pumping wave which is an ultrasonic pulse wave propagating through said acoustic medium so as to interact with said probing wave; C) detecting phase changes of said probing wave as affected by said pumping wave; and D) extracting the non-linear parameter of said acoustic medium from the detected phase changes of the probing wave.
Claim 2
Independent Claim
90 words
A method of measuring a non-linear parameter of an acoustic medium comprising processes: A) providing a probing beam of a probing wave which is a continuous ultrasonic wave propagating through said acoustic medium; B) providing a pumping wave which is an ultrasonic pulse wave propagating through said acoustic medium so as to interact with said probing wave; C) detecting phase changes of said probing wave as affected by said pumping wave; and D) extracting the non-linear parameter of said acoustic medium from the detected phase changes of the probing wave.
Claim 3
Dependent Claim
26 words
A method according to claim 1, wherein said pumping wave is radiated so as to intersect said probing beam, for example orthogonally of said probing beam.
Claim 4
Dependent Claim
24 words
A method according to claim 1, wherein said pumping wave is radiated along said probing beam in the opposite direction to said probing beam.
Claim 5
Independent Claim
59 words
A method according to any preceding claim, wherein process D) comprises measuring said phase changes of said probing wave as a function of position in said acoustic medium, and deriving a space distribution of the non-linear parameter by filtering said measured phase changes with a filter having frequency characteristics approximately the inverse of the spectrum of said pumping wave.
Claim 6
Dependent Claim
65 words
A method according to claim 4, further comprising a process for compensating- for deviation of measured values caused by a non-uniform space distribution of said pumping wave, said compensation being effected by: measuring said space distribution of said pumping wave in advance as a function of position along said probing beam and time, and varying filter characteristics in correspondence to the measured value space distribution.
Claim 7
Dependent Claim
91 words
Apparatus for measuring a non-linear parameter of an acoustic medium, comprising: first means, providing a probing beam which is a continuous ultrasonic wave, propagating through said acoustic medium; second means, providing a pumping wave which is an ultrasonic pulse wave, propagating through said acoustic medium so as to interact with said probing wave; third means, for detecting phase changes of said probing wave as affected by said pumping wave; and fourth means, for extracting a distribution of said non-linear parameter on the basis of detected phase changes of the probing wave.
Claim 8
Dependent Claim
91 words
Apparatus for measuring a non-linear parameter of an acoustic medium, comprising: first means, providing a probing beam which is a continuous ultrasonic wave, propagating through said acoustic medium; second means, providing a pumping wave which is an ultrasonic pulse wave, propagating through said acoustic medium so as to interact with said probing wave; third means, for detecting phase changes of said probing wave as affected by said pumping wave; and fourth means, for extracting a distribution of said non-linear parameter on the basis of detected phase changes of the probing wave.
Claim 9
Dependent Claim
61 words
Apparatus according to claim 6, wherein said first means comprise: first and the second ultrasonic transducers, located on opposite sides of said acoustic medium, the first transducer being operable to radiate said probing wave at a power level lower than that of said pumping wave, the second transducer being operable to receive said probing wave after propagation through said acoustic medium.
Claim 10
Dependent Claim
43 words
Apparatus according to claim 6 or 7, wherein said second means comprise: a third ultrasonic transducer, operable to radiate said pumping wave as a pumping wave beam whose beam width is sufficiently wide as to cover a measuring region of said acoustic medium.
Claim 11
Dependent Claim
82 words
Apparatus according to claim 6, 7 or 8, wherein said third means comprise: phase detecting means, for detecting said phase changes of said probing wave, and for producing an output signal representative of said phase changes in a time sequential train; and filter means, having a frequency characteristic approximately the inverse of that of said pumping wave, arranged for the receiving output signal of the phase detecting means, and for providing a spatially de-convoluted signal representing space distribution of said non-linear parameter.
Claim 12
Dependent Claim
28 words
Apparatus according to claim 8, wherein said third transducer is installed in a position such that it radiates said pumping wave in a direction intersecting the probing beam.
Claim 13
Dependent Claim
35 words
Apparatus according to claim 8, wherein said third transducer is installed in a position such that it radiates said pumping wave along said probing beam in a direction opposite to that of the probing beam.
Claim 14
Dependent Claim
62 words
Apparatus according to any one of claims 6 to 11, further comprising compensating means for compensating deviations of measured value caused by non-uniform space distribution of said pumping wave, said compensating means being a filter of a characteristic variable with time or a time-switchable filter bank offering various characteristics, corresponding to advance-measured values of spatial and temporal distribution of said pumping wave.
Claim 15
Dependent Claim
42 words
Apparatus according to any one of claims 6 to 12, further comprising means for improving S/N ratio, which comprises synchronous adding means for summing a plurality of measured values of said phase changes for corresponding positions, in synchronism with pumping wave pulses.
Claim 16
Dependent Claim
33 words
Apparatus according to any one of claims 6 to 13, further comprising means for scanning said probing beam to provide an image of a two or three dimensional distribution of said non-linear parameter.
Claim 17
Dependent Claim
53 words
Apparatus according to claims 7 and 8, wherein said third transducer has an annular structure positioned around said second transducer, or said second and third transducers have semicircular faces, together making up a circle, or said second and third transducers have rectangular shapes and said third transducer(s) is arranged alongside said second transducer.
Claim 18
Dependent Claim
45 words
Apparatus according to claims 7 and 8, wherein said second transducer and said third transducer consist of a single transducer element having a wide frequency characteristic covering both the frequency band of a received probing wave and the frequency band of a transmitted pumping wave.
Claim 19
Dependent Claim
37 words
Apparatus according to claims 7 and 8, wherein said second and third transducers together make up a layer type transducer, of which a front layer is said second transducer, and a back layer is said third transducer.
Claim 20
Dependent Claim
36 words
Apparatus according to claim 14, when read as - appended to claim 7, wherein said scanning is performed mechanically, by moving at least said first and second transducers as a pair, relative to said acoustic medium.
Claim 21
Dependent Claim
18 words
Apparatus according to claim 14, wherein said scanning is performed electronically, applying phased array or linear array technology.
Claim 22
Dependent Claim
33 words
Apparatus according to any of claims 6 to 19, further comprising variable amplifying means the gain of which is varied with time corresponding to propagation of said pumping wave in said acoustic medium.
Claim 23
Dependent Claim
74 words
Temperature measuring apparatus for measuring temperature or temperature distribution in a sample without physical contact with the measuring point comprising: apparatus as set forth in any one of claims 6 to 20; a memory means storing measured values of said non-linear parameter; a means deriving a difference of values of said parameter before and after a change of temperature of said acoustic medium; and a means for converting said difference to the temperature change.
Claim 24
Dependent Claim
34 words
Apparatus as set forth in claim 21, further comprising: a means deriving and memorizing a space distribution of said temperature change along a path of said probing wave which has propagated through said sample.
Claim 25
Dependent Claim
26 words
Apparatus as set forth in claim 21 or 22, further comprising scanning and displaying means for providing an image of said temperature distribution in said sample.
References Cited (Backward Citations)
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