Patent US4205686A successfully refreshed from Google Patents.
US4205686A
Expired / Lapsed
US
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Ultrasonic transducer and examination method
Assignee: Philips Nuclear Medicine Inc
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Filing: 1977-09-09
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Granted: 1980-06-03
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Expires: 1997-09-09
Abstract
Abstract An ultrasonic system and method for examining the structure of a subject body is disclosed. The system includes an improved ultrasonic transducer and power circuitry for electrically stimulating the transducer to produce an incident ultrasonic energy beam along a path extending into the subject. The incident beam produces echoes within the subject, some of which propagate back toward the transducer. The transducer, in response to received echoes, produces electrical signals bearing information about the structure of the subject. The system further includes circuitry for processing the electrical signals and a display apparatus responsive to the processed electrical signals for producing a visual display of subject structure. The transducer includes a concavo-convex piezoelectric emitter for producing ultrasonic energy having a dominant frequency, an acoustical impedance matching transformer and a coupling element. The impedance matching transformer includes a concavo-convex portion of material having a radius of curvature similar to that of the emitter, and being nested in contact with the emitter. The transformer has a uniform thickness equal to one-fourth of the wave length of the dominant ultrasonic frequency within the transformer. The characteristic acoustic impedance of the transformer material is approximately the geometric mean of the characteristic acoustic impedance of the emitter and the subject. The coupling element is made of material having acoustic characteristics similar to that of the subject body and is acoustically couplable between the impedance matching transformer and the subject surface, having a generally flat surface for contacting the subject.
Inventors
- 👤 Daniel J. Harris
- 👤 Richard B. Bernardi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 01:10
CPC Classifications
A; A61; A61B; A61B8/00; A61B8/42; A61B8/4272; A61B8/4281; G; G01; G01N; G01N29/00; G01N29/22; G01N29/221; G10; G10K; G10K11/00; G10K11/18; G10K11/26; G10K11/32
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
194 words
An ultrasonic transducer assembly for an ultrasonic system for examining an animal body by propagating ultrasonic energy through the body, said assembly comprising: (a) housing structure; (b) an emitter including a concavo-convex portion of piezoelectric material having concave and convex faces and being disposed within the housing structure for emitting acoustical energy having a frequency distribution about a dominant frequency in response to electrical stimulation of the emitter; (c) damping material adjacent the convex emitter face; (d) an impedance transformer including a portion of material having a concavo-convex curvature substantially matching that of said emitter and being nested adjacent the concave emitter face, said portion having a substantially uniform thickness of approximately one-fourth of a wave length of acoustical energy of said dominant frequency propagating through the portion, and (e) coupling structure including a portion of solid tissue equivalent material having acoustical characteristics similar to those of the tissue of the examined animal body, said coupling structure having a convex face disposed adjacent the concave side of the impedance transformer opposite the emitter and having a generally flat face opposite its said convex face for efficiently contacting substantially flat portions of the animal body.
Claim 2
Dependent Claim
194 words
An ultrasonic transducer assembly for an ultrasonic system for examining an animal body by propagating ultrasonic energy through the body, said assembly comprising: (a) housing structure; (b) an emitter including a concavo-convex portion of piezoelectric material having concave and convex faces and being disposed within the housing structure for emitting acoustical energy having a frequency distribution about a dominant frequency in response to electrical stimulation of the emitter; (c) damping material adjacent the convex emitter face; (d) an impedance transformer including a portion of material having a concavo-convex curvature substantially matching that of said emitter and being nested adjacent the concave emitter face, said portion having a substantially uniform thickness of approximately one-fourth of a wave length of acoustical energy of said dominant frequency propagating through the portion, and (e) coupling structure including a portion of solid tissue equivalent material having acoustical characteristics similar to those of the tissue of the examined animal body, said coupling structure having a convex face disposed adjacent the concave side of the impedance transformer opposite the emitter and having a generally flat face opposite its said convex face for efficiently contacting substantially flat portions of the animal body.
Claim 3
Dependent Claim
26 words
The ultrasonic transducer assembly of claim 1, wherein said coupling structure has a characteristic acoustical impedance similar to that of tissue of the subject animal body.
Claim 4
Dependent Claim
16 words
The ultrasonic transducer assembly of claim 1, wherein said coupling structure is made of elastomeric polyurethane.
Claim 5
Dependent Claim
17 words
The ultrasonic transducer assembly of claim 1, wherein said impedance transformer is constructed of an epoxy material.
Claim 6
Dependent Claim
19 words
The ultrasonic transducer assembly of claim 1, wherein said emitter comprises a portion of lead zirconate titanate ceramic material.
Claim 7
Dependent Claim
21 words
The ultrasonic transducer assembly of claim 1, further comprising: electrically conductive structure connected to said emitter for facilitating its electrical stimulation.
Claim 8
Dependent Claim
233 words
An ultrasonic system for examining structure of a subject, said system comprising: (a) a display apparatus for producing a visual image representing such structure; (b) processing circuitry responsive to electrical signals for actuating the display apparatus; (c) power actuation circuitry; (d) an ultrasonic transducer comprising: (i) housing structure; (ii) a focusing emitter having a concavo-convex configuration responsive to actuation from the power actuation circuitry for producing ultrasonic energy having a dominant frequency; (iii) damping material adjacent a convex face of the emitter; (iv) an impedance transformer including a portion of material having a concavo-convex curvature similar to that of said emitter and nested adjacent a concave emitter face, said portion of material having a substantially uniform thickness over a substantial area of said material of approximately one-quarter of a wave length of acoustical energy of the dominant frequency within the transformer, and (v) said emitter having a first characteristic acoustic impedance, and said transformer having a characteristic acoustic impedance of approximately the geometric mean of said first characteristic impedance and characteristic acoustic impedance of the subject, and (vi) a portion of solid material having acoustical characteristics similar to that of the subject being examined, said solid material having convex face nested substantially adjacent the concave face of the impedance transformer and a substantially flat face opposite the convex face for facilitating acoustical contact with a substantially flat portion of the subject being examined.
Claim 9
Dependent Claim
233 words
An ultrasonic system for examining structure of a subject, said system comprising: (a) a display apparatus for producing a visual image representing such structure; (b) processing circuitry responsive to electrical signals for actuating the display apparatus; (c) power actuation circuitry; (d) an ultrasonic transducer comprising: (i) housing structure; (ii) a focusing emitter having a concavo-convex configuration responsive to actuation from the power actuation circuitry for producing ultrasonic energy having a dominant frequency; (iii) damping material adjacent a convex face of the emitter; (iv) an impedance transformer including a portion of material having a concavo-convex curvature similar to that of said emitter and nested adjacent a concave emitter face, said portion of material having a substantially uniform thickness over a substantial area of said material of approximately one-quarter of a wave length of acoustical energy of the dominant frequency within the transformer, and (v) said emitter having a first characteristic acoustic impedance, and said transformer having a characteristic acoustic impedance of approximately the geometric mean of said first characteristic impedance and characteristic acoustic impedance of the subject, and (vi) a portion of solid material having acoustical characteristics similar to that of the subject being examined, said solid material having convex face nested substantially adjacent the concave face of the impedance transformer and a substantially flat face opposite the convex face for facilitating acoustical contact with a substantially flat portion of the subject being examined.
Claim 10
Dependent Claim
147 words
An acoustical energy transducer assembly for examining a subject, the transducer assembly comprising: (a) a curved concavo-convex emitter having a characteristic acoustic impedance and being responsive to the application of electrical energy thereto to emit substantially focused acoustical energy having a dominant frequency; (b) a concavo-convex acoustical impedance transformer disposed in a path of said acoustical energy, said acoustical impedance transformer having a uniform thickness substantially equal to an odd multiple of one-quarter of the wave length within the transformer of acoustical energy of the dominant frequency, said acoustical impedance transformer being disposed with its convex face substantially adjacent the concave face of the emitter, and (c) a plano-convex portion of solid material having acoustical velocity and impedance approximately equal to that of animal tissue having a high water content, said portion being positioned with its convex face substantially adjacent the concave face of the transformer element.
Claim 11
Dependent Claim
147 words
An acoustical energy transducer assembly for examining a subject, the transducer assembly comprising: (a) a curved concavo-convex emitter having a characteristic acoustic impedance and being responsive to the application of electrical energy thereto to emit substantially focused acoustical energy having a dominant frequency; (b) a concavo-convex acoustical impedance transformer disposed in a path of said acoustical energy, said acoustical impedance transformer having a uniform thickness substantially equal to an odd multiple of one-quarter of the wave length within the transformer of acoustical energy of the dominant frequency, said acoustical impedance transformer being disposed with its convex face substantially adjacent the concave face of the emitter, and (c) a plano-convex portion of solid material having acoustical velocity and impedance approximately equal to that of animal tissue having a high water content, said portion being positioned with its convex face substantially adjacent the concave face of the transformer element.
Claim 12
Dependent Claim
36 words
The acoustical energy transducer assembly of claim 8, wherein: said transformer is made of a material whose characteristic acoustic impedance is approximately the geometric mean of the characteristic acoustic impedances of the emitter and the subject.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-06-03 | 1983-12-03 | 1984-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-06-03 | 1987-12-03 | 1988-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-06-03 | 1991-12-03 | 1992-06-03 | $7700.00 | Window Closed / Lapsed |