EP0302554A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apodization of ultrasound transmission
Assignee: Philips North America LLC
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Filing: 1988-07-21
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Granted: —
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Expires: 2008-07-21
Abstract
Abstract An apodization attenuation circuit to achieve a selected percent Gaussian apodization of a focused ultrasound wavefront when transmitted from a linear or phased array (16). The circuit uses a string (88) of resistors (Ri), one resistor positioned between the drivers (92i) of each element (16i) in the transducer aray (16). Each node (89i) of the resistor string (88) functions as the reference potential input for one driver (92i). Each node (89i) includes a pair of normally open switches (iS1, iS2), one of which may (iS2) be closed to common and one of which (iS1) may be closed to full reference potential (V ). By closing four switches, two to common and two to full reference potential, a profile of potential of a selected percent Gaussian apodization can be achieved such that the output pulse magnitude of each transducer element (16i) in an aperture varies as a Gaussian function of its distance from the center of the aperture.
Inventors
- 👤 Robert Heathcote Russell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 04:53
CPC Classifications
G; G10; G10K; G10K11/00; G10K11/18; G10K11/26; G10K11/34; G10K11/341; G10K11/348; G01; G01S; G01S15/00; G01S15/88; G01S15/89; G01S15/8906; G01S15/8909; G01S15/8915; G01S15/8918; G01S7/00; G01S7/52; G01S7/52017; G01S7/52046; G01S7/52047; Y; Y10; Y10S; Y10S367/00; Y10S367/905
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
275 words
An apodization attenuation circuit to control the amplitude of pulses transmitted from each ultrasound transducer element in an array of N transducer elements comprising: an aperture of m transmitting elements within said array wherein 1 ≦ m ≦ N; means to excite said transducer elements to cause the transmission of ultrasound energy from said elements within said aperture; means to shape the distribution of electrical energy applied across said m transmitting transducer elements such that an acoustic axis passes through the center of said aperture in said array and the excitation energy decreases as a selected Gaussian function of distance from the center, characterized in that said means to shape the distribution of electrical energy comprises: a two wire power supply; means to determine which of said transducer elements are within said aperture and therefore transmitting; a string of N resistors, one for each of said transducer elements, said N resistors connected in series, the last resistor in said string being connected to the first; each node of said resistor string being connected to a driver circuit of one of said transducer elements and functioning as reference potential input for said driver circuit associated with that transducer element; connecting means to connect at least one node of said resistor string on each side of said acoustic axis within said aperture to the positive potential of said power supply and at least one node of said resistor string on each side of said acoustic axis outside said aperture to the common of said power supply such that the reference potential input from said resistor string to each of said driver circuits is said selected Gaussian function.
Claim 2
Dependent Claim
275 words
An apodization attenuation circuit to control the amplitude of pulses transmitted from each ultrasound transducer element in an array of N transducer elements comprising: an aperture of m transmitting elements within said array wherein 1 ≦ m ≦ N; means to excite said transducer elements to cause the transmission of ultrasound energy from said elements within said aperture; means to shape the distribution of electrical energy applied across said m transmitting transducer elements such that an acoustic axis passes through the center of said aperture in said array and the excitation energy decreases as a selected Gaussian function of distance from the center, characterized in that said means to shape the distribution of electrical energy comprises: a two wire power supply; means to determine which of said transducer elements are within said aperture and therefore transmitting; a string of N resistors, one for each of said transducer elements, said N resistors connected in series, the last resistor in said string being connected to the first; each node of said resistor string being connected to a driver circuit of one of said transducer elements and functioning as reference potential input for said driver circuit associated with that transducer element; connecting means to connect at least one node of said resistor string on each side of said acoustic axis within said aperture to the positive potential of said power supply and at least one node of said resistor string on each side of said acoustic axis outside said aperture to the common of said power supply such that the reference potential input from said resistor string to each of said driver circuits is said selected Gaussian function.
Claim 3
Dependent Claim
167 words
An apodization attenuation circuit as claimed in Claim 1, characterized in that the connecting means comprise: two normally open switches positioned between each node and each of said driver circuits; a first one of said switches being positioned between full reference potential and said driver circuit; a second one of said switches being positioned between common and said driver circuit; two of said first switches connected to driver circuits of transmitting transducer elements near the center of said aperture, one on each side of said centerline, being closed to full reference potential; two of said second switches connected to driver circuits of non-transmitting transducer elements, one outside each end of said aperture, being closed to common; whereby said profile of potential is achieved such that each driver circuit of each transducer element within said aperture receives through said resistor string a selected percent ≦ 100% to 100% of said reference potential as a function of the distance of said transducer element from said centerline of said aperture.
Claim 4
Dependent Claim
20 words
An apodization attenuation circuit as claimed in Claim 1 or 2, characterized in that said array is a linear array.
Claim 5
Dependent Claim
20 words
An apodization attenuation circuit as claimed in Claim 1 or 2, characterized in that said array is a phased array.
Claim 6
Dependent Claim
112 words
An apodization attenuation circuit as claimed in Claim 2, characterized in that it further comprises: a digital logic circuit to control the electrical excitation of said transducer elements; register means in said digital circuit to store waveform and apodization parameters for each scan of said ultrasound transducer; said stored apodization parameters including: a state indicating for each transducer element whether or not it is within the transmitting aperture for a particular scan; a state indicating for each transducer element whether one of said switches in its driver circuit should be closed to effect said profile of potential; and control means for selecting said apodization parameters for each scan of said ultrasound transducer.
References Cited (Backward Citations)
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