Ultrasonic probe
First Claim
1. An ultrasonic probe for ultrasonic inspection equipments, comprising:
- a plurality of transducer elements, each being a rectangular plate of a piezoelectric material with front and back electrode films respectively coated on front and back surfaces thereof, said plate having a width-to-thickness ratio of not greater than 0.8, said transducer elements being arranged in a row at intervals with their longer sides opposite to each other so that said plate can make a width extensional vibration as a fundamental vibration mode; and
an acoustic impedance matching layer, consisting of a uniformly thick inner layer of a first material placed on said row of said transducer elements to intimately cover said front electrode films of all the transducer elements and a uniformly thick outer layer of a second material placed on said inner layer to intimately cover the outer surface of said inner layer,the acoustic impedance of said first material being 2.5 to 9.5 times as large as the acoustic impedance of an object of ultrasonic inspection, the acoustic impedance of said second material being smaller than the acoustic impedance of said first material but is 1.6 to 2.7 times as large as the acoustic impedance of said object.
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Abstract
An ultrasonic probe particularly suitable for ultrasonic diagnostic equipments of the electronic scanning type is made up of a multiplicity of piezoelectric transducer elements, each in the shape of a rectangular plate with electrode films coated on both sides, arranged in a row at intervals and an acoustic impedance matching layer placed on the row of the transducer elements. The width-to-thickness ratio of each piezoelectric plate takes a value not greater than 0.8 and preferably between 0.4 and 0.7 so that the plate can vibrate in width expansion mode. It is highly preferable that the impedance matching layer has a laminated structure given by two layers which are different in acoustic impedance of the respective materials and individually have definite thicknesses.
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Citations
12 Claims
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1. An ultrasonic probe for ultrasonic inspection equipments, comprising:
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a plurality of transducer elements, each being a rectangular plate of a piezoelectric material with front and back electrode films respectively coated on front and back surfaces thereof, said plate having a width-to-thickness ratio of not greater than 0.8, said transducer elements being arranged in a row at intervals with their longer sides opposite to each other so that said plate can make a width extensional vibration as a fundamental vibration mode; and an acoustic impedance matching layer, consisting of a uniformly thick inner layer of a first material placed on said row of said transducer elements to intimately cover said front electrode films of all the transducer elements and a uniformly thick outer layer of a second material placed on said inner layer to intimately cover the outer surface of said inner layer, the acoustic impedance of said first material being 2.5 to 9.5 times as large as the acoustic impedance of an object of ultrasonic inspection, the acoustic impedance of said second material being smaller than the acoustic impedance of said first material but is 1.6 to 2.7 times as large as the acoustic impedance of said object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An ultrasonic probe for ultrasonic inspection equipments, comprising:
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a plurality of transducer elements, each being a rectangular plate of a piezoelectric ceramic material with front and back electrode films respectively coated on front and back surfaces thereof, said plate having a width-to-thickness ratio of not greater than 0.8, said transducer elements being arranged in a row at intervals with their longer sides opposite to each other so that said plate can make a width extension vibration as a fundamental vibration mode; and an acoustic impedance matching layer of a uniform thickness placed on said row of said transducer elements to intimately cover said front electrode films of all the transducer elements, said impedance matching layer consisting of a material of which acoustic impedance is 2 to 4 times as large as the acoustic impedance of an object of ultrasonic inspection. - View Dependent Claims (12)
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Specification