ULTRASONIC TRANSDUCER AND METHOD OF MANUFACTURING THE SAME
An ultrasonic transducer which can attenuate ultrasonic waves emitted toward the rear without increasing a thickness of a backing layer includes: a piezoelectric transducer which emits and receives ultrasonic waves; and the backing layer which is provided in contact with the rear of the piezoelectric transducer and which attenuates the ultrasonic waves emitted in a rear direction from the piezoelectric transducer. The backing layer includes a plurality of acoustic tubes formed in the rear direction from a plane of the backing layer that is in contact with the piezoelectric transducer. Each of the acoustic tubes has a different length based on a principle of superposition of acoustic waves. The acoustic tubes include an acoustic tube which has (i) a portion of the length formed in a direction perpendicular to the rear direction and (ii) the remaining portion of the length formed in a direction parallel to the rear direction.
1 . An ultrasonic transducer comprising:
a transducer which emits and receives ultrasonic waves; and
a backing material which is provided in contact with a rear of said transducer and which attenuates the ultrasonic waves emitted in a rear direction from said transducer,
wherein said backing material includes a plurality of reflectors formed in the rear direction from a plane of said backing material that is in contact with said transducer, each of said reflectors having a different length based on a principle of superposition of acoustic waves, and
said reflectors include a reflector which has (i) a portion of the length formed in a direction perpendicular to the rear direction and (ii) the remaining portion of the length formed in a direction parallel to the rear direction.
2 . The ultrasonic transducer according to claim 1 ,
wherein each of said reflectors has properties of an acoustic tube.
3 . The ultrasonic transducer according to claim 1 ,
wherein each of said reflectors is formed to have a length that is an integer multiple of a predetermined unit length, and
one of neighboring reflectors which has a greater length has a portion of the length bent in a direction perpendicular to the rear direction so as to be formed in the rear direction of another one of said neighboring reflectors having a smaller length, said neighboring reflectors being included in said reflectors.
4 . An ultrasonic transducer comprising:
a transducer which emits and receives ultrasonic waves; and
a backing material which is provided in contact with a rear of said transducer and which attenuates ultrasonic waves emitted in a rear direction from said transducer,
wherein said backing material includes a plurality of reflectors formed in the rear direction from a plane of said backing material that is in contact with said transducer, each of said reflectors being formed based on a Helmholtz resonator principle.
5 . The ultrasonic transducer according to claim 4 ,
wherein said reflectors have properties of the resonator, and
each of said reflectors has a neck length and a bore diameter that are designed to have a desired resonant frequency.
6 . The ultrasonic transducer according to claim 1 ,
wherein said backing material includes
a board and said reflectors, and
said reflectors are made of a material with an acoustic impedance different from an acoustic impedance of said board.
7 . The ultrasonic transducer according to claim 6 ,
wherein said reflectors are formed on said board by printing.
8 . A method of manufacturing an ultrasonic transducer which includes: a transducer which emits and receives ultrasonic waves; and
a backing material which (i) is provided in contact with a rear of the transducer, (ii) includes a board and a plurality of reflectors, and (iii) attenuates ultrasonic waves emitted in a rear direction from the transducer, said method comprising
forming the backing material which includes the reflectors by printing on the board a material with an acoustic impedance different from an acoustic impedance of the board, each of the reflectors having a different length based on a principle of superposition of acoustic waves and being formed in the rear direction from a plane of the backing material that is in contact with the transducer.
9 . The method of manufacturing an ultrasonic transducer according to claim 8 ,
wherein in said forming of the backing material, the reflectors are formed to include a reflector which has (i) a portion of the length formed in a direction perpendicular to the rear direction and (ii) the remaining portion of the length formed in a direction parallel to the rear direction.
10 . The method of manufacturing an ultrasonic transducer according to claim 8 ,
wherein said forming of the backing material includes:
forming, by printing, base materials each of which includes a plurality of grooves;
filling the grooves, by printing, with a material with an acoustic impedance different from an acoustic impedance of the base material; and
forming the backing material which includes the reflectors, by adhesively stacking the base materials printed in said forming of the base material and in said filling of the grooves.
11 . The method of manufacturing an ultrasonic transducer according to claim 10 ,
wherein in said forming of the base material, the base materials each of which includes a plurality of grooves which have different lengths based on the principle of superposition of acoustic waves are formed by printing.
12 . An ultrasonic diagnostic apparatus comprising the ultrasonic transducer according to claim 1 .