Acoustic probe and acoustic apparatus
An acoustic probe includes a plurality of transducers that receives acoustic waves and a supporting body including a supporting portion having a symmetrical concave surface, such as a spherical cap surface, which supports the transducers in a spiral array. The supporting position R at which the supporting portion supports the transducers is given as R(r 0 , θ, φ) [m, rad, rad] by a polar coordinate with respect to a center of the symmetrical concave surface by setting a sphere radius, a zenith angle, and an azimuth angle as “r 0 ”, “θ”, and “φ”, wherein the plurality of transducers is arrayed at a set azimuth angle spiral pitch in an azimuth angle direction and an axis direction spiral pitch set parallel to a central axis direction of the symmetrical concave surface, and wherein the azimuth angle spiral pitch is an angle acquired by dividing 2π by 1+golden number.
1. An acoustic probe comprising:
a plurality of transducers that receives acoustic waves; and
a supporting body including a supporting portion having a spherical surface which supports the plurality of transducers in a spiral array,
wherein a supporting position R at which the supporting portion supports the transducers is defined as R(r 0 , θ, φ) [m, rad, rad] by a polar coordinate with respect to a center of the spherical surface by setting a sphere radius, a zenith angle, and an azimuth angle as “r 0 ”, “θ”, and “φ”,
wherein the plurality of transducers is arrayed at a certain azimuth angle spiral pitch in an azimuth angle direction of the spiral array and a certain axis direction spiral pitch in an axial direction of the spiral array, and
wherein the azimuth angle spiral pitch is at an angle [rad] acquired by dividing 2π [rad] by 1+golden number, and
wherein the axis direction spiral pitch is parallel to a central axis direction of the spherical surface extending from the center to an extreme point.
2. The acoustic probe according to claim 1 , wherein the azimuth angle spiral pitch coincides with an azimuth angle difference Δφ between the two closest transducers to each other in a zenith angle θ direction.
3. The acoustic probe according to claim 1 , wherein the axis direction spiral pitch coincides with a distance Δz in the axis direction between the two closest transducers to each other in the zenith angle θ direction
Δ
z
=
z
i
-
z
i
-
1
=
r
0
(
cos
θ
i
-
cos
θ
i
-
1
)
=
r
0
cos
θ
N
-
1
-
cos
θ
0
N
-
1
.
4. The acoustic probe according to claim 1 , wherein the supporting portion supports the plurality of transducers to form only one spiral array.
5. The acoustic probe according to claim 1 , wherein the spiral array is a Fibonacci array.
6. The acoustic probe according to claim 1 , wherein, of the plurality of transducers, a starting point of the spiral array having a greatest zenith angle θ has a zenith angle θ of 8π/9 [rad] or more and π [rad] or less.
7. The acoustic probe according to claim 6 , wherein, of the plurality of transducers, an ending point of the spiral array having a smallest zenith angle θ has a zenith angle θ of π/3 [rad] or more and 3π/4 [rad] or less.
8. The acoustic probe according to claim 1 , wherein the transducers are piezo-type transducers having pyroelectric ceramics or capacitance-type transducers having cavities between electrodes.
9. The acoustic probe according to claim 1 , further comprising a light irradiation portion configured to irradiate a test subject with light.
10. The acoustic probe according to claim 9 , wherein the supporting portion supports the light irradiation portion at a position having a zenith angle greater than the zenith angle of the starting point.
11. The acoustic probe according to claim 9 , wherein the light irradiation portions are arranged on the supporting portion with uniform dispersibility.
12. The acoustic probe according to claim 11 , wherein a spiral array of the plurality of light irradiation portions has an azimuth angle spiral pitch 2π/(1+Ψ) which is in common with the pitch of the spiral array of the plurality of transducers.
13. The acoustic probe according to claim 11 ,
wherein the supporting portion supports the plurality of light irradiation portions in a spiral array that satisfies the following expressions
ϕ
j
=
±
2
π
j
1
+
Ψ
+
ξ
,
Ψ
=
1
+
5
2
,
and
θ
j
=
cos
-
1
[
cos
θ
0
+
cos
θ
M
-
1
-
cos
θ
0
M
-
1
j
]
,
wherein “M” represents a number of light irradiation portions, “j” represents an array number (0, 1, . . . , M−1) assigned from 0 to each transducer by designating a side having “π” of the zenith angle θ as a starting point, and “ξ” represents an azimuth angle difference between a starting point of an array of the light irradiation portions and a starting point of an array of the transducers.
14. The acoustic probe according to claim 2 , further comprising a camera having an imaging field facing toward the test subject at a position having a zenith angle greater than the zenith angle of the starting point.
15. The acoustic probe according to claim 2 , further comprising a port for supplying or discharging an acoustic matching liquid at a position having a zenith angle greater than the zenith angle of the starting point.
16. An acoustic apparatus comprising:
the acoustic probe according to claim 1 ; and
a scanning unit configured to make the acoustic probe move in translation motion.
17. The acoustic apparatus according to claim 16 further comprising a light source optically connected to the light irradiation portion.
18. The acoustic apparatus according to claim 16 , further comprising a signal processing unit configured to acquire information about a test subject based on a signal received by the acoustic probe.
19. The acoustic probe according to claim 1 , wherein the symmetrical concave surface is an inner surface of a spherical cap.
20. The acoustic probe according to claim 1 , wherein an axis of the spiral array coincides with an axis of the symmetrical concave surface.
21. An acoustic probe comprising:
a plurality of transducers that receive acoustic waves; and
a supporting body including a supporting portion having a symmetrical concave surface which supports the plurality of transducers,
wherein a supporting position R at which the supporting portion supports the transducers is defined as R(r 0 , θ, φ) [m, rad, rad] by a polar coordinate with respect to a center of the symmetrical concave surface by setting a sphere radius, a zenith angle, and an azimuth angle as “r 0 ”, “θ”, and “φ”,
wherein the supporting portion supports the transducers in a spiral array that satisfies the following expressions
Δ
ϕ
=
ϕ
i
-
ϕ
i
-
1
=
±
2
π
1
+
Ψ
,
Ψ
=
1
+
5
2
,
and
Δ
z
=
z
i
-
z
i
-
1
=
r
0
(
cos
θ
i
-
cos
θ
i
-
1
)
=
r
0
cos
θ
N
-
1
-
cos
θ
0
N
-
1
,
wherein “N” represents a number of transducers, “i” represents an array number (0, 1, . . . , N−1) assigned from 0 to each transducer by designating a side having “π” of the zenith angle θ as a starting point.
22. The acoustic probe according to claim 21 , wherein the supporting portion supports the plurality of transducers to form only one spiral array.
23. The acoustic probe according to claim 21 , wherein the spiral array is a Fibonacci array.
24. The acoustic probe according to claim 21 , wherein, of the plurality of transducers, a starting point of the spiral array having a greatest zenith angle θ has a zenith angle θ of 8π/9 [rad] or more and π [rad] or less.
25. An acoustic probe comprising:
a plurality of transducers that receive acoustic waves; and
a supporting body including a supporting portion having a symmetrical concave surface which supports the plurality of transducers,
wherein a supporting position R at which the supporting portion supports the transducers is defined as R(r 0 , θ, φ) [m, rad, rad] by a polar coordinate with respect to a center of the symmetrical concave surface by setting a sphere radius, a zenith angle, and an azimuth angle as “r 0 ”, “θ”, and “φ”,
wherein the supporting portion supports the transducers in a spiral array that satisfies the following expressions
ϕ
i
=
±
2
π
i
1
+
Ψ
,
Ψ
=
1
+
5
2
,
and
θ
i
=
cos
-
1
[
cos
θ
0
+
cos
θ
N
-
1
-
cos
θ
0
N
-
1
i
]
,
wherein “N” represents a number of transducers, “i” represents an array number (0, 1, . . . , N−1) assigned from 0 to each transducer by designating a side having “π” of the zenith angle θ as a starting point.
26. The acoustic probe according to claim 25 , wherein the supporting portion supports the plurality of transducers to form only one spiral array.
27. The acoustic probe according to claim 25 , wherein the spiral array is a Fibonacci array.
28. The acoustic probe according to claim 25 , wherein, of the plurality of transducers, a starting point of the spiral array having a greatest zenith angle θ has a zenith angle θ of 8π/9 [rad] or more and π [rad] or less.