Ultrasonic search unit and method for producing the same
View Patent ↗An ultrasonic search unit includes a piezoelectric element for transmitting/receiving an ultrasonic wave, and an acoustic matching layer for transmitting the ultrasonic wave transmitted/received by the piezoelectric element to a subject to be measured, wherein the acoustic matching layer is formed of a cured layer obtained by irradiating a resin for optical forming with laser light. It also may be possible that the acoustic matching layer is formed of a plurality of stacked layers, and different fillers are mixed in the respective layers, whereby the acoustic impedance of the respective layers is changed. A liquid resin for optical forming is supplied to a tank, and is cured to a predetermined shape by irradiation with laser light. Accordingly, an ultrasonic search unit and a method for producing the same are provided, in which an acoustic matching layer with a required thickness is formed with good precision without being bonded, whereby a variation in thickness of adhesive layers, a variation in characteristics caused by air bubbles, and degradation are unlikely to occur.
1. An ultrasonic search unit, comprising:
a piezoelectric element for transmitting/receiving an ultrasonic wave; and
an acoustic matching layer for transmitting the ultrasonic wave transmitted/received by the piezoelectric element to a subject to be measured,
wherein the acoustic matching layer is formed of a cured layer obtained by irradiating a resin for optical forming with laser light, and
wherein the acoustic matching layer is formed directly on the piezoelectric element.
2. An ultrasonic search unit according to claim 1 , wherein the acoustic matching layer is stacked on the piezoelectric element.
3. An ultrasonic search unit according to claim 1 , wherein the acoustic matching layer is formed with a filler in an amount of 0 mass % to 2000 mass % mixed in the resin.
4. An ultrasonic search unit according to claim 3 , wherein the filler has at least two different average particle sizes.
5. An ultrasonic search unit according to claim 3 , wherein the filler has at least two different densities.
6. An ultrasonic search unit according to claim 3 , wherein the filler is at least one selected from the group consisting of tungsten, ferrite, and alumina.
7. An ultrasonic search unit according to claim 3 , wherein the acoustic matching layer is formed of a plurality of layers, a ream composition of a lower layer has a relatively high density, and a resin composition of a surface layer has a relatively low density.
8. An ultrasonic search unit according to claim 1 , wherein the acoustic matching layer has an acoustic impedance that changes in a thickness direction.
9. An ultrasonic search unit according to claim 8 , wherein the acoustic matching layer is formed of a plurality of layers, a lower layer thereof has a relatively high acoustic impedance, and a surface layer thereof has a relatively low acoustic impedance.
10. An ultrasonic search unit according to claim 8 , wherein the acoustic matching layer includes a plurality of stacked layers in which a content of a filler is change between adjacent layers.
11. An ultrasonic search unit according to claim 1 , wherein the acoustic matching layer is formed of a plurality of layers, and there is no adhesive layer between the layers.
12. An ultrasonic search unit according to claim 1 , wherein the acoustic matching layer is formed of a plurality of layers, and there are no air bubbles between the layers.
13. A method for producing an ultrasonic search unit including a piezoelectric element for transmitting/receiving an ultrasonic wave and an acoustic matching layer for transmitting the ultrasonic wave to a subject to be measured, the method comprising forming the acoustic matching layer directly on the piezoelectric element by irradiating a liquid resin for optical forming supplied to a tank with laser light to form a cured layer.
14. A method for producing an ultrasonic search unit according to claim 13 , wherein a filler in an amount of 0 mass % to 2000 mass % is mixed in the resin.
15. A method for producing an ultrasonic search unit according to claim 13 , wherein an amount of a filler in a lower layer is set to be relatively high, and an amount of a filler in a surface layer is set to be relatively low by using a settling speed of the filler mixed in the resin, whereby an acoustic impedance is changed in a thickness direction.
16. A method for producing an ultrasonic search unit according to claim 13 , wherein a resin layer constituting the acoustic matching layer is formed of a plurality of layers, a density of the resin layer in a lower layer is set to be relatively high, and a density of the resin layer in a surface layer is set to be relatively low, whereby an acoustic impedance is changed in a thickness direction.
17. A method for producing an ultrasonic search unit according to claim 13 , wherein the density of the resin layer is controlled by changing at least one selected from the group consisting of an added amount of a filler, an average particle size thereof, and a density thereof.
18. A method for producing an ultrasonic search unit according to claim 13 , wherein the filler is at least one selected from the group consisting of tungsten, ferrite, and alumina.
19. A method for producing an ultrasonic search unit according to claim 13 , wherein the acoustic matching layer is formed of a plurality of layers, and there is no adhesive layer between the layers.
20. A method for producing an ultrasonic search unit according to claim 13 , wherein the acoustic matching layer is formed of a plurality of layers, and there are no air bubbles between the layers.