JP6827804B2 - Detector array and information acquisition device with it - Google Patents

Description

The present invention relates to a probe array and an information acquisition device having the probe array.

Using light with a wavelength of about 600-1500 nm, which has good transmission characteristics to living tissues, the formation of new blood vessels and oxygen metabolism of hemoglobin associated with tumor growth are determined from the light absorption characteristics of hemoglobin contained in the blood of the tumor. There is a technique used for diagnosis. One such technique is to use the photoacoustic effect.

The photoacoustic effect is a phenomenon in which when a substance is irradiated with pulsed light of about nanoseconds, the substance absorbs light energy corresponding to its light absorption characteristics, and the substance momentarily expands to generate an elastic wave. .. This elastic wave is detected by an ultrasonic probe to obtain a received signal. By mathematically analyzing this received signal, it is possible to image the absorption characteristics in the living body based on the sound pressure distribution of elastic waves generated by the photoacoustic effect. Hemoglobin has a higher absorption rate of near-infrared light than water, fat, and protein constituting living tissues, and is therefore suitable as a method for measuring new blood vessels and oxygen metabolism as described above. Clinical research is being actively pursued to apply such photoacoustic effects to the diagnosis of breast cancer and the like.

As a photoacoustic device, Patent Document 1 discloses a device having a hemispherical acoustic wave detector in which a plurality of acoustic elements are spirally arranged and a hemispherical container in which a test site of a subject is placed. This device is provided with a hemispherical acoustic wave detector under the container, and has a light irradiation unit that irradiates the test site with light below the hemispherical acoustic wave detector. In this device configuration, the resolution of the acquired information image is improved by receiving the acoustic waves from the test site in many directions.

Similarly, Patent Document 2 is an example of a photoacoustic device similar to Patent Document 1, and a plurality of acoustic elements are spirally arranged in a hemispherical acoustic wave detector.

International Publication No. 2010/03817 U.S. Pat. No. 5,713,356

In order to obtain highly reliable image quality, it is necessary to arrange the probes having transducers in close proximity to each other and mount them at high density. However, neither of Patent Documents 1 and 2 describes a method of fixing a probe having a transducer in a bowl-shaped (hemispherical) container at a high density.

An object of the present invention is to provide a probe array capable of arranging probes including a transducer that transmits and receives ultrasonic waves to a bowl-shaped housing at a high density.

The probe array according to the present invention has a bowl-shaped support portion having a plurality of holes and a transducer configured to be able to convert an acoustic wave and an electric signal, and a cylinder provided in the holes. A probe array having a shaped probe, wherein the bowl-shaped support has an axis of rotational symmetry, a curved surface including an inner surface of the bowl-shaped support, and a tubular probe. The perpendicular line from the point where the central axis intersects to the axis of rotational symmetry has a plurality of intersections, and the first intersection of the plurality of intersections and the bowl-shaped intersection with respect to the first intersection. The distance from the second intersection adjacent to the top side of the support is
It is characterized in that it is larger than the distance between the first intersection and the third intersection adjacent to the first intersection on the side opposite to the top side.

According to the probe array according to the present invention, a probe including a transducer can be provided at a high density on a bowl-shaped support portion.

Sectional drawing which shows the structure of the acoustic wave unit 100 which concerns on Embodiment 1 of this invention. Sectional drawing which explained in detail the ultrasonic probe 103 which concerns on Embodiment 1 of this invention A bird's-eye view of the shape of the ultrasonic probe 103 according to the first embodiment of the present invention. The figure which displayed a part of the ultrasonic probe 103 on the bottom surface side of the housing 104 which concerns on Embodiment 1 of this invention. FIG. 6 is a detailed view of the arrangement state of the ultrasonic probe 103 mounted on the outer surface of the housing 104 according to the first embodiment of the present invention. An enlarged view of the arrangement of the ultrasonic probe 103 at the bottom of the housing 104 according to the first embodiment of the present invention. An enlarged view of the arrangement of the ultrasonic probe 103 at the position farthest from the bottom of the housing 104 according to the first embodiment of the present invention. The figure which shows that the reference point of the 1st and 2nd ultrasonic probe 103 which concerns on Embodiment 1 of this invention was projected on the axis of rotational symmetry of a housing 104 connecting a subject 102 from the bottom of the housing 104. The first, 14, 22, and 35th ultrasonic probes 103 according to the first embodiment of the present invention are placed on an arbitrary surface perpendicular to the axis of rotational symmetry connecting the bottom of the housing 104 and the subject 102. Diagram showing the projection The figure which showed another structure of the ultrasonic probe 103 which concerns on Embodiment 1 of this invention. The figure which showed the case where the structure shown in FIG. 10 was adopted in FIG. 9 which concerns on Embodiment 1 of this invention. The figure explaining the second alternative structure of the ultrasonic probe 103 which concerns on Embodiment 1 of this invention. The figure explaining the relationship between the constant A and the value which divided "i" by "s-1" which concerns on Embodiment 2 of this invention. The figure expressed using concrete values (constant A = 2, s = 20) in order to deepen understanding of FIG. 13 which concerns on Embodiment 2 of this invention. The figure expressed using concrete values (constant A = 5, s = 20) in order to deepen understanding of FIG. 13 which concerns on Embodiment 2 of this invention. A cross-sectional view of the probe array according to the embodiment of the present invention, and an enlarged view thereof. Projected onto the axis of rotational symmetry of the housing 104 connecting the subject 102 from the bottom of the housing 104 between the i-th and i + 1-th of the ultrasonic probe 103 when the constant A according to the second embodiment of the present invention is 2. The figure which calculated the difference of the reference point of the ultrasonic probe 103 concretely Projected onto the axis of rotational symmetry of the housing 104 connecting the subject 102 from the bottom of the housing 104 between the i-th and i + 1-th of the ultrasonic probe 103 when the constant A according to the second embodiment of the present invention is 20. The figure which calculated the difference of the reference point of the ultrasonic probe 103 concretely FIG. 1 of the first embodiment according to the third embodiment of the present invention is a diagram illustrating an acoustic wave unit 300 having no light irradiation unit 101. FIG. 1 of the first embodiment according to the fourth embodiment of the present invention is used to explain that the device is adapted to the subject information acquisition device.

The probe array according to the embodiment of the present invention will be described with reference to FIG. The upper part of FIG. 16 is a cross-sectional view of the probe array, and an enlarged view of a part of the cross-sectional view is shown at the lower part.

The probe array 100 according to the present embodiment has a bowl-shaped support portion 104 having a plurality of holes 1600 and a transducer (not shown) configured to be able to convert an acoustic wave and an electric signal, and has holes. It has a tubular transducer 103 provided in the 1600. Further, the rotation center axis 1602 of the bowl-shaped support portion 104, the curved surface 1603 including the inner surface of the bowl-shaped support portion 104, and the central axis of the tubular probe (rotation center axis (FIG. 3) described later). The perpendicular line 1604 from the intersection 1601 to the axis of rotational symmetry 1602 and has a plurality of intersections 1605. The probe array 100 according to the present embodiment is characterized by the positional relationship of a plurality of intersection points 1605. That is, the distance between the first intersection of the plurality of intersections 1605 and the second intersection adjacent to the top side of the bowl-shaped support with respect to the first intersection is the first intersection. It is larger than the distance between the first intersection and the third intersection adjacent to the side opposite to the top side. In FIG. 16, the first intersection is 1605-1, the second intersection is 1605-2, the third intersection is 1605-3, and the distance between the first intersection 1605-1 and the second intersection 1605-2 is n1. , The interval between the second intersection 1605-2 and the third intersection 1605-2 is set to n2. At this time, n1 is larger than n2. With such a configuration, a plurality of probes can be provided on the support portion at a high density.

Further, the distance between the adjacent intersections among the plurality of intersections may be reduced on the axis of rotational symmetry toward the direction away from the top, but the distance between the adjacent intersections among the plurality of intersections may be reduced. Some may be the same. Here, the top side is the bottom side of the support portion 104, and the direction away from the top on the axis of rotational symmetry is the direction of the arrow side of 1602 in FIG. In the present embodiment, the distances between adjacent intersections among the plurality of intersections 1605 are n1> n2> n3, but some of them may have the same distance.

Further, here, it is assumed that among the plurality of intersections, numbers from 1 to s (s is the total number of the probes) are assigned in order from the top in the direction away from the top on the axis of rotational symmetry. At this time, a plurality of probes can be provided so that the distance ni between the i-th intersection (1 <i <s, i is a positive integer) and the i + 1-th intersection satisfies the following relational expression. ..

In the above formula (3), A is a constant of 1 or more, Zmin is the distance from the top to the intersection at the position closest to the top among the plurality of intersections, and Zmax is the distance from the top to the plurality of intersections. It represents the distance to the intersection at the position farthest from the top.

Further, the probe may be arranged so as to protrude from the outer surface of the bowl-shaped support portion. The protruding structure can be used as a fixing portion to the supporting portion.

Further, since the seal member is provided between the probe and the support portion, the intrusion of liquid can be suppressed.

The probe is not particularly limited, but a capacitance type transducer or a piezoelectric type transducer can be used. Capacitive transducers are also called CMUTs (Capacitive Micro-machined Ultrasonic Transducers) and are capable of transmitting and receiving ultrasonic waves (acoustic waves) over a high band.

Further, the information acquisition device can be configured by further including the probe array according to the present embodiment and an information acquisition unit that acquires information about the subject based on at least an electric signal obtained by the probe.

(Embodiment 1)
When a probe including a transducer is provided on the bowl-shaped support, the spiral arrangement including the Fibonacci sequence is one of the methods that can be arranged at high density, but since these are arranged unevenly, they are fixed. It is necessary to arrange them so that there is no interference of the mechanical parts.

When arranging a probe having an acoustic element in a hemispherical container, the mounting area is small because the distance from the axis of symmetry passing through the center of gravity of the hemispherical container is short on the bottom surface side of the hemispherical container. There was a problem that they interfered with each other. Therefore, it has been difficult to mount the probe at high density.

The probe array according to the present embodiment solves such a problem. Details will be described below.

FIG. 1 is a cross-sectional view showing the configuration of an acoustic wave unit (probe array) 100 according to the first embodiment.

Reference numeral 101 is a light irradiation unit. The light irradiation unit 101 is an optical system that irradiates a subject 102, which will be described later, with pulsed light of about nanoseconds. Reference numeral 102 denotes a subject, such as a part of a human body or an animal, such as a hand, a leg, or a breast. Reference numeral 103 denotes an ultrasonic probe (probe), which receives an acoustic wave generated from the subject 102. This internal configuration will be described later, and will be omitted here. The material of the ultrasonic probe 103 is a structural material such as metal or resin. When a plurality of ultrasonic probe 103s are provided in the acoustic wave unit 100, resin molding is preferable in consideration of manufacturing cost, but the material is combined with the material of the support portion (hereinafter referred to as a housing) 104 described later. May be selected. These ultrasonic probe 103s are spirally arranged in a housing 104, which will be described later. There are various types of spirals such as logarithmic spirals and archimedean spirals, but here we use spirals with Fibonacci numbers. Further, as shown by the arrow shown in FIG. 1, these ultrasonic probes are arranged so that when the subject 102 is placed at the measurement position, its extension lines are gathered at substantially one point toward the subject 102. It is suitable. Further, these ultrasonic transducers 103 are arranged in the housing 104 so as to be substantially equidistant from the subject 102. As a result, the same ultrasonic probe can be arranged, which works effectively in terms of cost and exchangeability.

Reference numeral 104 denotes a hemispherical housing (hereinafter referred to as a housing), which supports the light irradiation unit 101 and the ultrasonic probe 103. The housing 104 has a spherical shape on both the inner and outer surfaces thereof. As for the shape, the inner surface having a small radius of curvature and the outer surface having a radius of curvature larger than that preferably have the same center of curvature, but they do not necessarily have to be the same. In this example, the housing 104 is hemispherical, but the shape of the housing 104 does not necessarily have to be spherical, and the inner side surface may be concave. The inner surface may be a paraboloid, a hyperboloid, an ellipsoid, a polyhedron, or any other shape as long as it does not interfere with the reception of acoustic waves. Similarly, the outer surface may be a paraboloid, a hyperboloid, an ellipsoid, a polyhedron, or any other shape. Since a plurality of ultrasonic probe 103s are fixed to the outer surface, it is preferable that the fixed surface of the housing 104 has the same shape. Therefore, in this example, it has a spherical shape. The housing 104 is provided with two types of holes. The first is to allow the pulsed light of the light irradiation unit 101 to pass through. The second is to receive the acoustic wave of the ultrasonic probe 103, and a plurality of holes corresponding to the ultrasonic probe 103 are provided. The central axis of the latter hole is the same as the central axis of the ultrasonic probe 103.

FIG. 2 is a cross-sectional view illustrating the ultrasonic probe 103 in detail. Reference numeral 105 denotes an acoustic wave conversion element, which converts an acoustic wave and an electric signal to each other. In the case of this figure, the acoustic wave is converted into an electric signal. As a member constituting the acoustic wave conversion element, a polymer piezoelectric membrane material typified by PZT (lead zirconate titanate), a polymer piezoelectric membrane material typified by PVDF (polyvinylidene fluoride), or the like is used. Can be done. Further, a capacitance type element may be used, and a CMUT (Capacitive Micro-machined Ultrasonic Transducers) or the like can be used. Reference numeral 106 denotes a sealing member, which is between the housing 104 and the ultrasonic probe 103 so that a matching agent such as water or gel contained in the housing 104 does not leak from the housing 104 in order to reduce the decrease in the attenuation of the pulsed light. It is provided. In the figure, the seal member 106 is an O-ring, and the member may be any material as long as it does not deteriorate with water or a matching agent, for example, fluorine-based rubber. As another example, an adhesive is also possible, but an O-ring is preferable in consideration of exchangeability. Further, in this example, one O-ring is used, but two O-rings may be used in consideration of sealing property. Reference numeral 107 denotes a circuit for processing a signal between the acoustic wave conversion element 105 and a system (not shown). In this figure, this circuit 107 is used for signal processing when a signal is received, but on the contrary, includes a circuit which performs signal processing when a signal is transmitted. Reference numeral 108 denotes a wiring 1, which connects the acoustic wave conversion element 105 and the circuit 107. Reference numeral 109 denotes wiring 2, which connects a signal between the circuit 107 and a system (not shown). Reference numeral 110 denotes a fixed portion (hereinafter referred to as a fixed portion) 110 of the ultrasonic probe 103, which is a portion fixed to the housing 104. The fixing portion 110 is provided with two holes through which a fastening member (not shown) is passed. FIG. 3 shows a bird's-eye view of the shape of the ultrasonic probe 103. As shown in this figure, the fixing portions 110 are provided at two locations on the outer surface of the ultrasonic probe 103. The fixed portion 110 preferably has a curvature. Further, it is preferable that the curvature of the fixing portion 110 is substantially the same along the outer surface of the housing 104 because the fixing portion 110 can be easily fixed to the housing.

A method of arranging the ultrasonic probe 103 on the housing 104 will be described in detail. FIG. 4 is a view showing a part of the ultrasonic probe 103 on the bottom surface side of the housing 104. As described above, in the first embodiment, a spiral having a Fibonacci number is used in the arrangement of the ultrasonic probe 103. The characteristic of this arrangement is that the adjacent ultrasonic probes 103 divide the circumference into two by a golden ratio of 1: (1 + √5) / 2 around the axis of rotational symmetry connecting the bottom of the housing 104 and the subject 102. It is a point that is deviated by the narrower angle and the golden angle (approximate value 137.508 degrees). The numbers shown in FIG. 4 indicate the order of arrangement of the ultrasonic probes 103, the one at the bottom of the housing 104 is 1, the second from the bottom is 2, and the same is true for 3, 4 thereafter. Is numbered. As described above, the second ultrasonic probe 103 is located at a position deviated by 137.508 degrees counterclockwise with respect to the first one around the axis of rotational symmetry connecting the bottom of the housing 104 and the subject 102. Similarly, the third ultrasonic probe 103 is located at a position offset by 137.508 degrees counterclockwise with respect to the second one about the axis of rotational symmetry connecting the bottom of the housing 104 and the subject 102. Subsequent ultrasonic probe 103 repeats the process. Here, as described above, each ultrasonic probe 103 is oriented toward the subject 102 so that its extension lines are gathered at substantially one point, and is approximately equidistant to the subject 102. They are arranged so that they do not interfere with each other. Looking at this arrangement in detail, it has features such as arrows AA, BB, and CC shown in the figure. Arrows AA indicate those at positions 103 to 135 of the 33rd ultrasonic probe. It can be seen that the numbers increase by 34 from the 33rd arrow A to the 135th arrow A. The relationship of the arrows AA has a similar relationship around the axis of rotational symmetry connecting the bottom of the housing 104 and the subject 102. For example, the twelfth ultrasonic probe 103, which is rotated clockwise with respect to the 33rd ultrasonic probe 103 and is adjacent to the thirty-third ultrasonic probe 103, also increases by 34 in the same manner as the arrows AA, and is increased by 34, 46, 80, 114. It is 148. Arrows BB have the same concept as arrows AA. In the figure, arrows BB indicate the 7th ultrasonic probe 103 to the 137th, and it can be seen that the numbers are incremented by 13. Similar to the arrows AA, the arrows BB also have a similar relationship around the axis of rotational symmetry connecting the bottom of the housing 104 and the subject 102. The same applies to the arrows CC. Arrows CC indicate from the 7th ultrasonic probe 103 to the 154th ultrasonic probe 103rd, and are incremented by 21 here. The increase amounts of arrows AA, BB, and CC, 34, 13, and 21, are all Fibonacci numbers. Although not indicated by arrows, 55 and 89 are also Fibonacci numbers. For example, taking the 7th ultrasonic probe 103 as an example, the number of ultrasonic probes 103 of 62 and 117 increases by 55. It can be seen that the 96th ultrasonic probe 103 has increased by 89. This arrangement is maintained from the bottommost ultrasonic probe 103 of the housing 104 to the farthest ultrasonic probe 103. Therefore, the distance between the ultrasonic probes 103 must be a distance that maintains the relationship. For example, in FIG. 4, it is the distance between the first ultrasonic probe 103, the 22nd ultrasonic probe 103, the 14th ultrasonic probe 103, and the 35th ultrasonic probe 103. .. The distance referred to here indicates the distance between the reference points of the ultrasonic probe 103, and in FIG. 4, the centers of the circles, that is, the central axis of the ultrasonic probe 103 and the acoustic wave conversion element 105. Refers to the intersections of. As described above, since the relationship is maintained, the same applies to the other ultrasonic probe 103. Suppose that the 56th ultrasonic probe 103 is taken up instead of the first ultrasonic probe 103. In this case, the 22nd ultrasonic probe 103 is replaced with the 77th one, the 14th is replaced with the 69th, and the 35th is replaced with the 90th. Again, this relationship is the same for the ultrasonic probe 103, which is farthest from the bottom of the housing 104. The distances between the first, 22nd, 14th, and 35th ultrasonic probe 103s are unequal, and the four reference points are connected to form a quadrilateral. More specifically, the 1st and 22nd distances are the shortest, followed by the 14th and 35th distances, the 1st and 14th distances, and the 22nd and 35th distances are the longest.

FIG. 5 is a detailed view of the arrangement state of the ultrasonic probe 103 mounted on the outer surface of the housing 104. In this figure, wiring 109 is not shown. In the figure, D is two points obtained by projecting the reference points of adjacent ultrasonic probe 103s on the bottommost side onto an arbitrary surface perpendicular to the rotation axis connecting the bottommost part of the housing 104 and the subject 102, and the rotation axis. It is an angle formed by the intersection of the above-mentioned vertical arbitrary surfaces. Similarly, in the figure, E is an arbitrary reference point of adjacent ultrasonic probes 103 having the same relationship at a position away from the bottom and perpendicular to the rotation axis connecting the bottom of the housing 104 and the subject 102. It is an angle formed by the intersection of two points projected on a surface, the rotation axis, and an arbitrary surface perpendicular to the surface. As shown in this figure, since the holding portion 110 is provided on the outer surface of the ultrasonic probe 103, the ultrasonic probe 103 easily interferes with the ultrasonic probe 103. As described above, the density occupied by the ultrasonic probe 103 is almost the same even at the farthest point from the bottom of the housing 104. That is, since the densities of the ultrasonic probe 103 are the same at both the bottom and the farthest part of the housing 104, it is shown that the number of the ultrasonic probes 103 is small on the bottom surface side of the housing 104. At this time, the angle D is the largest on the bottommost side of the housing 104, gradually decreases as the distance from the bottommost portion increases, and becomes loose at the farthest point. Let me explain in a little more detail. FIG. 6 is an enlarged view of the arrangement of the ultrasonic probe 103 at the bottom of the housing 104. Two points in which the reference points of adjacent ultrasonic probe 103s on the bottommost side of F in the figure are projected onto an arbitrary vertical plane with respect to the rotation axis connecting the bottommost part of the housing 104 and the subject 102, and the rotation axis. An angle formed by the intersection of any of the vertical planes. On the other hand, FIG. 7 is an enlarged view of the arrangement of the ultrasonic probe 103 at the position farthest from the bottom of the housing 104. In the figure, G is an arbitrary shape in which the reference point of the adjacent ultrasonic probe 103 at the position farthest from the bottommost side is perpendicular to the rotation axis connecting the bottommost part of the housing 104 and the subject 102, as in FIG. It is an angle formed by the intersection of two points projected on a surface, the rotation axis, and an arbitrary surface perpendicular to the surface. It can be seen that the angle F in FIG. 6 is larger than the angle G in FIG. From the above, it can be seen that the angle formed by the fixing portions 110 between the ultrasonic probe 103 becomes looser as the distance from the bottom end side of the housing 104 increases. In other words, on the bottommost side of the housing 104, the fixed portion 110 of the ultrasonic probe 103 is more easily approached by the adjacent ultrasonic probe 103.

In consideration of the above, the ultrasonic probe 103 may loosen the angle F on the bottom surface side of the bottom of the housing 104 with respect to the angle G. To do this, the first and second ultrasonic probes projected onto the axis of rotational symmetry of the housing 104 connecting the subject 102 from the bottom of the housing 104 when the ultrasonic probes 103 are arranged as shown in FIG. The interval between the reference points of the child 103 is the widest. Then, the interval is narrowed as the distance from the bottommost side increases. FIG. 8 is a diagram showing that the reference points of the first and second ultrasonic probes 103 are projected onto the axis of rotational symmetry of the housing 104 connecting the subject 102 from the bottom of the housing 104. In the figure, n indicates the distance between the reference points projected from the bottom of the housing 104 on the axis of rotational symmetry of the housing 104 connecting the subject 102 with the reference points of the first and second ultrasonic probes 103. In this figure, when n is widened, the second ultrasonic probe 103 moves in the direction from the bottom of the housing 104 toward the subject 102. When this is repeated, the 14th, 22nd, and 35th ultrasonic probes 103 shown in this figure also move. FIG. 9 shows that the 1st, 14th, 22nd, and 35th ultrasonic probes 103 are projected onto an arbitrary surface perpendicular to the axis of rotational symmetry connecting the bottom of the housing 104 and the subject 102. It is a figure. The dotted line in the figure shows after each ultrasonic probe 103 has been moved from the conventional position in the direction from the bottom of the housing 104 toward the subject 102. Further, in the figure, H is the reference point of the 14th ultrasonic probe 103 before movement projected on an arbitrary surface, and the reference point of the first ultrasonic probe 103 is the axis of rotational symmetry with the arbitrary surface. The angle formed by the line connecting the intersections with. In the figure, J is a reference point of the 14th ultrasonic probe 103 after movement projected on an arbitrary surface, and the reference point of the 1st ultrasonic probe 103 is defined by the arbitrary surface and the axis of rotational symmetry. The angle formed by the lines connecting the intersections. The reference point of each ultrasonic probe 103 is a black circle at the center of the circle. In this figure, it can be seen that the angle narrows from H to J before and after the movement of the 14th ultrasonic probe 103. It is easy to imagine that the 22nd and 35th ultrasonic probes will change in the same way. That is, the angle corresponding to the angle F described in FIG. 6 is narrowed, and interference between the ultrasonic probes 103 can be suppressed.

This relationship can be expressed mathematically as follows. The distance between arbitrary reference points (hereinafter referred to as adjacent distances) of the first and second ultrasonic probe 103 projected onto the axis of rotational symmetry of the housing 104 connecting the subject 102 from the bottom of the housing 104 is n1. And. Then, assuming that n2, n3, ..., And ns-1 (s is the total number of ultrasonic probes 103), the following equation (1) is obtained.

n1>n2>n3>...> ns-1 equation (1)
(S is the total number of ultrasonic probes 103)
This relationship is caused by the fact that the angle D gradually narrows and changes to the angle E as the angle D moves away from the bottommost portion of the housing 104 in FIG.

Here, each n may be arbitrarily determined, and by mounting the n on the housing 104 and appropriately determining the n, a plurality of ultrasonic probes 103 can be arranged at a high density.

The angle F described in FIG. 6 becomes looser as the distance from the bottom is increased. Therefore, even if the adjacent intervals are equalized from the middle of the process, it may be established. In that case, the following equation may be used.

n1>n2>n3>n4> n5 = n6 ... = ns-1 equation (2)
(S is the total number of ultrasonic probes 103)
In the equation (2), the adjacent spacing is the same from n = 5, but the position from which the adjacent spacing is equal depends on the shape and size of the ultrasonic probe 103 and the size of the housing 104. It is preferable to determine the above as appropriate. Further, it is preferable that the sum of each n in the formula (2) is equal to or smaller than the sum of each n in the formula (1). The reason is that when it becomes large, it is not arranged at a higher density than the arrangement determined by the formula (1).

Further, although the shape of the ultrasonic probe 103 is shown in FIG. 2, it is not necessary to limit the shape to this. FIG. 10 shows another structure of the ultrasonic probe 103. In this figure, 111 is a male screw configured on the ultrasonic probe 103. Further, the housing 104 is shown by hatching, and a female screw is similarly formed on the housing 104 so as to mesh with the male screw 111. As can be seen from this figure, since the diameter formed by the male screw is larger than the diameter of the sealing member 106, the hole formed in the housing 104 is large. On the other hand, in the ultrasonic probe 103 shown in FIG. 2, the fixing portion 110 is formed on the outside. Therefore, if it is possible to compare both shapes and improve the mounting density with the structure shown in FIG. 10, it is better to fix the mounting using the fixing portion provided on the outer surface of the housing. It is possible to do. FIG. 11 is a diagram showing a case where the structure shown in FIG. 10 is adopted in FIG. The dotted line of the first ultrasonic probe 103 in the figure shows the size of the ultrasonic probe 103 of FIG. 2, and the solid line shows the ultrasonic probe 103 of FIG. As explained above, the solid line has a larger diameter due to the formation of the male thread. As you can see in the figure, the four ultrasonic probes 103 drawn with solid lines are almost close to each other, but the ultrasonic probes are set so as to satisfy the relationship of Eq. (1) or (2). By providing it, it can be arranged apart as shown by the dotted line. In this configuration, when the ultrasonic probe 103 is mounted on the housing 104, it is necessary to rotate and insert the ultrasonic probe 103. Therefore, when highly accurate positioning is required, it is necessary to provide a positioning mechanism in addition to this structure.

FIG. 12 is a diagram illustrating a second alternative structure of the ultrasonic probe 103. In this figure, 112 is an abutting portion provided on the outer periphery of the ultrasonic probe 103. The abutting portion 112 abuts on the abutting surface provided inside the housing 104. Reference numeral 113 denotes a holding ring for pushing the abutting portion 112 of the ultrasonic probe 103. A male screw is formed on the outer circumference of the presser ring 113. On the other hand, a female screw is formed on the housing 104 so as to mesh with the male screw. In another structure described with reference to FIG. 10, the ultrasonic probe 103 was mounted on the housing 104 while rotating. On the other hand, in the second separate structure of the present figure, the ultrasonic probe 103 is inserted until the abutting portion 112 abuts on the housing 104, and the pressing ring 113 is screwed to fix the ultrasonic probe 103. Although not shown in this figure, if a mechanism for determining the orientation of the abutting portion 112, for example, a part of the ultrasonic probe 103 is D-cut, and the housing 104 is also processed to match the orientation, the orientation can be adjusted. It is also possible to decide. Since this structure also has a structure in which the ultrasonic probe 103 is pressed and fixed by the pressing ring 113, the diameter of the pressing ring 113 is always larger than that of the seal member 106. However, as in FIG. 10, if the structure described in FIG. 12 can improve the mounting density, this structure may be used. This relationship is similar to the relationship shown in FIG.

Although the structural proposal of the ultrasonic probe 103 is shown in FIGS. 2, 10 and 12, the fixing method is a structure using a mechanical fastening method such as a screw or a presser ring. On the other hand, as a fixing method, there is also a fixing method using an adhesive. However, as described above, it is necessary to put water in the housing 104, and when the ultrasonic probe 103 fails, it is necessary to surely remove the adhesive. Therefore, it is preferable to use a mechanical fastening method in consideration of exchangeability.

The direction of the ultrasonic probe 103 is such that the fixed portion 110 faces up and down with respect to the paper surface in FIG. 5, but it may be rotated at any angle. For example, in this figure, the ultrasonic probe 103 may be rotated 90 degrees around the rotation axis. By appropriately selecting the adjacent intervals toward the optimum angle in this way, it is possible to arrange the ultrasonic probe 103 at a high density.

As described above, by setting the adjacent intervals of the ultrasonic probe 103 as shown in the equations (1) and (2), the ultrasonic probe 103 can be arranged at a high density. Therefore, highly reliable image acquisition becomes possible.

(Embodiment 2)
In the first embodiment, the distance between the reference points of the ultrasonic probe 103 projected onto the axis of rotational symmetry of the housing 104 connecting the subject 102 from the bottom of the housing 104 as described in the formulas (1) and (2). Have a relationship with. As a result, the ultrasonic probe 103 can be arranged at a high density, indicating that highly reliable image acquisition is possible. In this method, the adjacent intervals are arbitrarily selected according to the structure, so that the degree of freedom is large. However, when several hundred or more ultrasonic probe 103s are arranged in the housing 104, it cannot be said that the design is efficient. More preferably, it is desirable to be able to set the adjacent spacing in the axis of symmetry using a certain relationship. In view of this point, the equation (3) expresses the adjacent interval by a mathematical formula.

In the formula (3), ni is the ultrasonic probe 103 projected onto the axis of rotational symmetry of the housing 104 connecting the subject 102 from the bottom of the housing 104 between the i-th and i + 1-th of the ultrasonic probe 103. The difference between the reference points is shown. i indicates the i-th ultrasonic probe 103 (the bottommost ultrasonic probe 103 is the first) counting from the bottom. A is a constant of 1 or more (hereinafter referred to as constant A), and s corresponds to the total number of ultrasonic probes 103. Zmax is the position of the reference point of the ultrasonic probe 103 projected onto the axis of rotational symmetry of the housing 104 connecting the subject 102 from the bottom of the housing 104 of the s-th ultrasonic probe 103. Zmin indicates the position of the reference point of the ultrasonic probe 103 projected onto the axis of rotational symmetry of the housing 104 connecting the subject 102 from the bottom of the housing 104 of the first ultrasonic probe 103. It goes without saying that s is an integer of 2 or more because this equation shows the relationship between the arrangement of the ultrasonic probe 103.

Equation (3) will be described in a little more detail. In this equation, "s-1" is the number of intervals between the reference points of the ultrasonic probe 103 projected onto the axis of rotational symmetry of the housing 104 connecting the subject 102 from the bottom of the housing 104 of the ultrasonic probe 103. Represents. The ratio of the i-th to the i + 1-th is calculated by dividing "i" by "s-1" and subtracting it from the constant A. At this time, as the number of i increases, the value obtained by dividing "i" by "s-1" increases, so if this is subtracted from the constant A, the result becomes small. That is, it is shown that the ultrasonic probe 103 takes a smaller value as it moves away from the bottom. When the i-th number is changed from 1 to s-1 and the obtained results are compared, it can be seen that the relationship is in the equation (1). Then, the obtained result is divided by the denominator. The denominator is the sum of the results obtained above. The ratio of i-th and i + 1-th is standardized by dividing by the denominator. For confirmation, it can be seen that the total sum of the ratios from the 1st to the s-1st is 1. Finally, "Zmax-Zmin" is multiplied. This is the difference between the reference point of the ultrasonic probe 103 at the bottom projected on the axis of rotational symmetry of the housing 104 connecting the subject 102 from the bottom of the housing 104 and the reference point at the position farthest from the bottom. The i-th height is calculated by multiplying by.

Further, the constant A in the equation (3) will be described in detail. FIG. 13 is a diagram illustrating the relationship between the constant A and the value obtained by dividing “i” by “s-1”. Further, FIGS. 14 and 15 are diagrams expressed using specific values in order to deepen the understanding of FIG. 13. In FIGS. 14 and 15, s is 20 in each case, constant A is 2 in FIG. 14, and constant A is 5 in FIG. 15, and i indicates a part of 1 to 3 for convenience of explanation. .. As already explained, the value obtained by dividing "i" by "s-1" is always 1 or less. In FIG. 13, when this is calculated, when “i = 1”, the value obtained by dividing “i” by “s-1” is 0.053. This does not change in FIGS. 14 and 15. On the other hand, the differences α, β, and γ of the values obtained by dividing “i” by “s-1” from the constant A (the area in the white frame in the figure) depend on the constant A. That is, when the constant A is small, the dominant rate for the differences α, β, and γ is large with respect to the value obtained by dividing “i” by “s-1”, but when the constant A is large, these are relative. Becomes smaller. This can be understood by looking at FIGS. 14 and 15. More specifically, α, β, and γ in FIG. 14 are calculated to be 1.947, 1.895, and 1.842, and the ratio of γ and α is 0.946. On the other hand, α, β, and γ in FIG. 15 are calculated as 4.947, 4.895, and 4.842, and the ratio of γ and α is 0.979. The larger the constant A, the smaller the dominant ratio. Become. FIG. 16 is an enlarged view of n1, n2, and n3 calculated by the equation (3). As can be seen from the equation (3), n1, n2, and n3 have a proportional relationship with α, β, and γ, and the ratio described with reference to FIGS. 14 and 15 determines the height of the n1, n2, and n3. Decide.

I will continue the explanation with another example. FIG. 17 shows the axis of rotational symmetry of the housing 104 connecting the subject 102 from the bottom of the housing 104 between the i-th and the i + 1th of the ultrasonic probe 103 when the constant A is 2 and FIG. 18 is the constant A of 20. This is a concrete calculation of the difference "ni" of the reference points of the ultrasonic probe 103 projected on. Here, the total number s in this figure is set to 20, and "Zmax-Zmin" is set to 1 for simplicity. In FIG. 14, when the ratio of n19 and n1 is taken, it becomes 0.514, but in FIG. 15, when the same ratio is taken, it becomes 0.953, and "ni" can be determined by how to take the constant A. You can. Actually, it is preferable to tentatively set the constant A, arrange the ultrasonic probe 103 on the housing 104, and then set the constant A to be the densest. If A is small, the difference between the ratios becomes large, so that the ratio may become too narrow at the position farthest from the bottom of the housing 104. On the contrary, when A is made extremely large, the difference between the ratios becomes small, so that the pitch approaches almost the same pitch and becomes narrow near the bottom.

In the second embodiment, the relationship as in the equation (2) described in the first embodiment does not hold. The reason is that in the first embodiment, each ratio is arbitrarily determined, whereas in the second embodiment, the equation (3) is calculated. It can be seen that the mounting density decreases when the relationship as shown in the equation (2) is introduced in the equation (3). For example, in the case shown in FIG. 15, if the same values as n5 are taken from n5 to n19, the total sum of n1 to n19 in FIG. 15 is 1, but in this case, it is understood from the fact that it exceeds 1. Can be done.

As described above, by using the equation (3) with respect to the adjacent intervals of the ultrasonic probe 103, it is possible to efficiently determine each position of several hundred or more ultrasonic probes 103.

It is needless to say that this equation (3) is an example and is not limited to this, and an example having a similar idea can be applied.

(Embodiment 3)
FIG. 3 is a diagram illustrating an acoustic wave unit 300 having no light irradiation unit 101 in FIG. 1 of the first embodiment. It should be noted that those having the same reference numerals as those in the first embodiment are the same, and the description thereof will be omitted.

In this figure, the ultrasonic probe 103 has an acoustic wave conversion element 105 as described with reference to FIG. 1, and transmission / reception is performed using the acoustic wave conversion element 105. Specifically, a transmission signal is sent from a system (not shown) to the acoustic wave conversion element 105 to convert it into an acoustic wave. The converted acoustic wave is sent to the subject 102 and reaches the subject 102. The arrived acoustic wave is reflected by the subject 102, converted again by the acoustic wave conversion element 105 in the ultrasonic probe 103, and sent to a system (not shown).

Here, the relationship between the ultrasonic probe 103 and the housing 104 is the same as in FIG. As described above, the same effect as that described in the first and second embodiments can be obtained in the third embodiment.

(Embodiment 4)
FIG. 4 is a diagram for explaining that the information acquisition device (subject information acquisition device) is adapted to FIG. 1 of the first embodiment. Further, in this figure, it can be applied to both the first embodiment and the second embodiment. In this figure, those having the same reference numerals as those of the first and second embodiments are the same, and the description thereof will be omitted. Further, the arrows shown in the figure indicate the flow of pulsed light, acoustic waves, and signals.

Reference numeral 401 denotes a light source, which emits pulsed light of about nanoseconds. This light source can be selected according to the subject. For example, in the case of a living body, a light source having a wavelength of about 600 nm to 1500 nm can be selected. The pulsed light emitted from the light source 401 passes through the light irradiation unit 101 and is irradiated to the subject 102. In the subject 102, the irradiated pulsed light absorbs light energy and momentarily expands to generate an acoustic wave. The generated acoustic wave is captured by a plurality of ultrasonic probes 201, and signal strength and phase information is transmitted to the subject information acquisition device 402. The subject information acquisition device 402 reconstructs an image based on the position information of each ultrasonic probe and the obtained signal, and displays the image on the image display 403.

As described above, the pulsed light generated from the light source is applied to the subject, the elastic wave generated from the subject is captured by the ultrasonic probe, and the signal obtained from each ultrasonic probe and each An image of the subject can be obtained by reconstructing the image based on the position information of the ultrasonic probe.

The third embodiment is different in that the light irradiation unit 101 is not provided, but the same is true in that the received signal is transmitted to the subject information acquisition device 402 and then displayed on the image display 403. Has the effect of.

100 Detector array 101 Light irradiation unit 102 Subject 103 Detector 104 Support unit (housing)
105 Transducer (acoustic wave conversion element)
106 Seal member 107 Signal processing circuit 108 Wiring 1
109 wiring 2

Claims (9)

A bowl-shaped support with multiple holes,
It has a transducer that is configured to be able to convert acoustic waves and electrical signals, and has a tubular probe provided in the hole and
A probe array with
A perpendicular line from the intersection of the rotational symmetry axis of the bowl-shaped support portion, the curved surface including the inner surface of the bowl-shaped support portion, and the central axis of the tubular probe to the rotational symmetry axis. Has multiple intersections,
The distance between the first intersection of the plurality of intersections and the second intersection adjacent to the top side of the bowl-shaped support portion with respect to the first intersection is
A probe array characterized in that it is larger than the distance between the first intersection and a third intersection adjacent to the first intersection on the side opposite to the top side. The probe array according to claim 1, wherein the distance between adjacent intersections among the plurality of intersections becomes smaller on the axis of rotational symmetry toward a direction away from the top. The probe array according to claim 1, wherein a part of the intervals between adjacent intersections among the plurality of intersections is the same. When the plurality of intersections are numbered from 1 to s (s is the total number of the probes) on the axis of rotational symmetry in the direction away from the top, the i-th intersection (1). The probe array according to claim 1 or 2, wherein the distance ni between <i <s and i are positive integers) and the i + 1th intersection satisfies the following relational expression.

In the above formula (3), A is a constant of 1 or more, Zmin is the distance from the top to the intersection at the position closest to the top among the plurality of intersections, and Zmax is the distance from the top to the plurality of intersections. It represents the distance to the intersection at the position farthest from the top. The probe array according to any one of claims 1 to 4, wherein the probe is arranged so as to protrude from the outer surface of the bowl-shaped support portion. The probe array according to any one of claims 1 to 5, wherein a seal member is provided between the probe and the support portion. The probe array according to any one of claims 1 to 6, wherein the probe has a capacitance type transducer. The probe array according to any one of claims 1 to 6, wherein the probe has a piezoelectric transducer. An information acquisition device comprising the probe array according to any one of claims 1 to 8 and an information acquisition unit that acquires information about a subject based on at least the electric signal.

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