Ultrasonic probe and ultrasonic imaging apparatus using the same
In order to provide an ultrasonic probe capable of suppressing the influence of multiple reflections occurring on the interface of a transducer with a CMUT chip and a backing layer, an ultrasonic probe of the present invention has a structure where an acoustic lens 14 , transducers 11 - 1 to 11 - m , and a backing layer 12 are laminated. Each of the transducers 11 - 1 to 11 - m has a CMUT chip, and the backing layer 12 is formed of a material with a value of substantially the same acoustic impedance as the acoustic lens 14.
1. An ultrasonic probe comprising:
a structure including an acoustic lens, a transducer, and a backing layer that are laminated,
wherein the transducer has a CMUT chip, a thickness of the transducer in a lamination direction is set to be smaller than 200 μm,
wherein the backing layer is formed of a material with a substantially same value of acoustic impedance as the acoustic lens, and
wherein the acoustic impedance of the backing layer is a range for suppressing multiple reflections of an ultrasonic wave, so as to suppress the multiple reflections of a boundary between the transducer and the backing layer.
2. The ultrasonic probe according to claim 1 , wherein the acoustic impedance of the backing layer is acoustic impedance of an object in contact with the acoustic lens.
3. The ultrasonic probe according to claim 1 , wherein a representative value of the acoustic impedance of the acoustic lens is 1.4 MRayl.
4. The ultrasonic probe according to claim 1 , wherein the acoustic impedance of the backing layer is 1.1 MRayl to 9.4 MRayl.
5. The ultrasonic probe according to claim 1 , wherein a thickness of the transducer is equal to or less than 50 μm.
6. The ultrasonic probe according to claim 5 , wherein the acoustic impedance of the backing layer is 3.7 MRayl to 9.4 MRayl.
7. The ultrasonic probe according to claim 1 , wherein a thickness of the transducer is equal to or less than 25 μm, and the acoustic impedance of the backing layer is 3.3 MRayl to 7.9 MRayl.
8. The ultrasonic probe according to claim 1 , wherein a thickness of the transducer is equal to or less than 10 μm, and the acoustic impedance of the backing layer is 1.1 MRayl to 1.8 MRayl.
9. The ultrasonic probe according to claim 1 , wherein a thickness of the transducer is equal to or less than 5 μm, and the acoustic impedance of the backing layer is 2.0 MRayl to 9.4 MRayl.
10. The ultrasonic probe according to claim 1 , wherein a material of the transducer is silicon, a material of the acoustic lens is silicon rubber, and a material of the backing layer is butyl rubber.
11. The ultrasonic probe according to claim 1 , wherein a thickness of the transducer is equal to or less than 5 μm, and a thickness of an adhesive layer between the transducer and the backing layer is equal to or less than 10 μm.
12. The ultrasonic probe according to claim 11 , wherein the adhesive layer is a die attach film.
13. An ultrasonic imaging apparatus comprising:
an ultrasonic probe that transmits and receives ultrasonic waves to and from an object;
an image creation unit that creates an image from signals acquired by the ultrasonic probe;
a display unit that displays the image; and
a control unit that controls a focal point of the ultrasonic probe according to a depth of a measured portion of the object,
wherein the ultrasonic probe is the ultrasonic probe according to claim 1 .
14. The ultrasonic probe according to claim 1 , wherein the transducer is disposed adjacent to the backing layer.