JPS58163347A - Ultrasonic three-dimensional fan-shaped scanning probe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a probe that scans an ultrasonic beam in a fan shape;
The present invention relates to an ultrasonic three-dimensional fan-shaped scanning probe for observing two or more different fan-shaped scanning sections within a 4IK object.

[Conventional technology and problems]

Fan-shaped scanning by an ultrasonic beam is performed in a living body am.
It has the advantage of being able to observe the interior over a wide field of view from one small contact point. In particular, when observing the heart, a considerable area of the heart can be observed by avoiding interference with the ribs and touching the narrow area between the ribs. Sectoral scanning is used exclusively because it can be used on both sides.

However, conventionally, only one fan-shaped scanning section is viewed, so accurate I! There was a drawback that columns could not be done. After all, the heart beats and moves, and because of the movement of breathing, the heart as a whole moves back and forth and from side to side. For this - cross section I! If you only look at the sides, it is unclear which part of the heart the cross section is from, so you can change the position of the probe in relation to your body by hand or rotate it 90 degrees around the probe axis. Observations of the desired cross section are being carried out to confirm this. In this case, since it is done manually, it is difficult to maintain geometric accuracy in each posture adjustment. “To solve this problem, it may be possible to maintain the Il tentacle in a constant horizontal position, but this is inconvenient because it interferes with the breathing movement, and I have not seen any attempts to do so yet.

Therefore, an attempt was made to mechanically rotate the probe 90 degrees around the axis of the inner probe tube while holding the probe's outer container in a fixed position relative to the body, but the probe was too large. The disadvantage is that the error is still large due to the fact that it is difficult to maintain a completely constant hold in the Bunko, that it is not simultaneous in time, and that the time required for one rotation is long.

Apart from this application, the inventor uses two separate probes to
By knowing their relative positions using angle detectors attached to the link arms and joints, we devised a method to simultaneously observe two cross-sections and their relative positions over an hour, making accurate three-dimensional observation possible.

However, in this case, since two probes are used, two contact points with the body are required. In general, it is possible to find a valid contact point when observing the heart of young people under the prime of life, but as they get older, there are more and more cases in which only one valid contact point can be found, and the ratio is 40%. or 50%.

In view of the above-mentioned circumstances, there is a demand for a system in which two or more different cross sections can be electronically switched at high speed or observed completely simultaneously through one contact part, but there have been no reports on attempts to do so.

Electronic sector scanning is typically performed using a phased array. In this case, the transducer is multi-layered, for example with two orthogonal sector scans,
It has also been separately devised by the inventor that each layer is responsible for a different scanning plane, each scanning plane using a different frequency, and thus can be operated completely simultaneously.

However, in these cases, the drawbacks are that the processing of the multilayer transducer is complicated, and the phase control circuit is complicated and expensive.

[Purpose of departure]

The present invention eliminates the various drawbacks described above, and allows scanning of a plurality of different layers through one contact St while keeping the attitude of the probe toward the object to be measured, such as a living body, constant. High-speed electronic switching of surfaces and/or complete simultaneous KI! The purpose of the present invention is to provide an inexpensive and small three-dimensional fan-shaped scanning probe that enables measurement.

[Composition of the release]

In order to achieve the above object, an ultrasonic three-dimensional layered scanning probe according to the present invention includes an element array in which a plurality of ultrasonic transducer elements are arranged, a window through which ultrasonic waves enter and exit,
an ultrasonic transmission medium filled in a front chamber formed between the element array and the liao; the ultrasonic transducer array element is selectively operated as an aperture to transmit ultrasonic waves into a beam; In an ultrasonic scanning probe that scans an object circumscribed to the window with an ultrasonic beam by transmitting and receiving and changing some or all selections, the ultrasonic beam from the element array The element array is constructed in a multi-dimensional or multi-dimensional manner so that all selected scanning lines pass through the window or substantially one intersection point near the window and scan in a fan shape, It is characterized by cross-sectional and/or three-dimensional fan-shaped scanning. Scanning details number 1: A plurality of ultrasonic transducer elements are selectively activated from the element array to focus and form an ultrasonic beam, and the selected ultrasonic transducer
By changing some or all of the juicer elements, the center position at the transmitting and receiving point of the ultrasonic beam is moved.

[Embodiments of the invention]

Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 1 shows an embodiment of the present invention showing the relationship between the transducer arrangement, the scanning line intersection point, and the window.
A diagram showing an example of a W array, (B) a diagram showing an example of three orthogonal linear arrays, and (C)! Figures illustrating an example of Tritas flat Wi lid arrangement; -) is a sectional view showing the probe structure of -).

1 is a window, 2 to 5 are transducer rows, 6 is a transducer surface, 13 is a sound absorbing material, and 14 is a front chamber.

In FIG. 1 (1), the three transducer rows 2.3 and 4 are
They are arranged in an arc shape, and #t are arranged in parallel so that the center of curvature is at the window IK.

The shape of the arc can be slightly corrected if necessary. Figure 1 (
In -), the fan-shaped scanning plane formed by the transducer array 2 is arranged in a square orthogonal to the window 10 surface.

The fan-shaped scanning plane formed by the transducer rows 3 and 4 passes through the center point O of the window 1, but the plane is not orthogonal to the window 10, but obliquely. Therefore, transducer arrays 3 and 4 appear parallel in FIG. Because of this oblique angle, IIK is not completely parallel, and there is a necessary force t to distort it. The respective ymm arrays 2.3 and 4 can be thought of as an arcuate version of the so-called linear play, which is a completely linear array of transducers generally used for abdominal diagnosis. A large number of piezoelectric elements made from smoke-shaped PZT plates are arranged in a row.

Its operating method may be the same as that of a general linear array, and a number of adjacent elements are selected and used as the aperture of the beam concentrator. The center of the beam becomes the scanning line. The scanning line is moved by changing the position t of the selection element. By driving +1 elements to obtain a scanning line shifted by half a pitch, or by sequentially controlling the timing phase of transmission and reception from near the center to the periphery of the elements that make up the group, it is possible to The ultrasound beam width focal point can be electronically set or dynamically controlled. However, if phase control is not performed, the focal point will be determined by a geometric arrangement and will be the 1-rate center of the circular arc. The beam width in the direction perpendicular to the scanning plane can be focused by giving each zygomatic element a concave curvature in the sound wave emission direction, or by using a cylindrical lens with its cylindrical axis bent along an arc. This can be done by adding K to the front of a linear array. In this way, techniques used in general linear arrays can be applied. Figure 1 (
Jl) shows the case where the 1-rate center of the circular arc coincides with the intersection point of each scanning line. Further, although an example is shown in which this intersection point coincides with the center O of the window 1, it does not necessarily have to coincide with the center O of the window 1, if necessary.

FIG. 1(1) is a sectional view showing a specific probe structure taken along a plane passing through the center point 0 of the window 1 and the center line of the transducer array 2 in FIG. 1(1).

The probe has a front chamber 1 in the shape of a square pyramid with a window 1 at the apex.
4 and circuit connections to the elements, etc., and are made as a single unit. The vibrator rows 2, 3 and 4 of type II arrangement are installed on the bottom of the square pyramid in front [14]. At this time, the side surfaces other than the window 1 and the inner surface of the front chamber 14, which is integrated with the back surface of the transducer rows 2, 3 and 4 in the line-layer arrangement, are covered or formed with as much sound-absorbing material 13 as possible. Ru. The inside of the front 1114 is filled with water, castor oil, liquid paraffin, and fluorine oil, and the transducer rows 2, 3, 4 and II! 1
This is the transmission path for ultrasonic waves between the Transducer row 2.3 and 4
The Zeng 1114 inner-layer scanning plane formed by Zeng 1114 extends point-symmetrically to the opposite side through point 0, forming three different fan-shaped scanning planes in the object to be measured. When the transducer arrays 2.3 and 4 are operated at the same frequency, each scanning plane is operated in a temporally switched manner. However, if the constituent elements of each array are 1, for example, transducer row 2 is 3.5 MHJ, 3 is L2SMHi, 41tt,
1.5 By increasing the number of 1hiR1ll created by MHNII and adding different 0HIRP modulation methods, three transducer rows 2 arranged in l/sll can be used.
, 3 and 4 simultaneously, and the received signals are discriminated by a filter, the three scanning planes can be scanned simultaneously.

In Fig. 1(b), the transducer arrays 2 and 5 have INK whose respective scrap-shaped scanning circles are orthogonal to each other, and all scanning lines pass near the axis l or at a point 0 on the window 1, crossing each other. It is arranged like this. The intersecting part of transducer rows 2 and 5 is not a rectangular shape but an IJ box-shaped element that is divided vertically and horizontally, and can be connected vertically and used as part of transducer row 2, or connected horizontally. It is used as part of the transducer array 5. The transducer arrays 2 and 5 are operated out of phase so that when one is using the central crossing section, the other is using the other sections. The other structure, operation, and scanning are the same as in Fig. 1(a), and it is also possible to scan mutually orthogonal fan-shaped scanning planes inside the object to be measured outside 1 by time switching or when fully opened. It is.

In FIG. 1(C), the transducer surface 6 is not arranged in a linear arrangement, but in a planar arrangement in the form of a matrix, with Kll number of transducers arranged on a spherical surface centered at point 0. In this case, the center can be centered at any position on the plane A three-dimensional fan-shaped scan can be performed.

FIG. 2 is a diagram showing a specific example of the structure of a transducer array having a multilayer structure according to the present invention v4, in which (a) is a diagram showing an example of an am array, and (l)) is a diagram showing two orthogonal linear arrays. It is a figure showing an example. 7.8 and 10 are transducer rows, 71.72.73
... is a piezoelectric element, 8' is a piezoelectric plate, 8o is a ground electrode,
81, 82, 83... are signal electrodes, 11 is a reflection plate,
12 is a non-polarized plate, and 13 is a sound-absorbing material, as shown in FIG. The child row 7 includes piezoelectric elements 71, 72.7 which are made by dividing a piezoelectric element made of PZT (zircon lead titanate) or the like with a center frequency of &5 MHJ.
3rd prize. The transducer row 8 is made of, for example, PVDF (poly-7
It has an organic piezoelectric plate 8' such as vinylidene tsulfide, and has a center frequency of, for example, 24! Adjusted to SMH7. The organic piezoelectric plate 8' has K signal electrodes 81, 82, 83 on one side (front side in the figure).
On the other side (the back side in the figure), a K ground electrode 80 is arranged on the entire surface. A signal electrode and a ground electrode are also arranged on the piezoelectric elements 71, 72, 73, etc., respectively. PZT is a ceramic and is not flexible, so piezoelectric elements 71, 72, 73, etc. must be made as independent pieces one by one, or a cape slit that cannot penetrate all the way through to the back of the plate must be cut into a disc-shaped plate. It can also be made as a whole. PVDF is flexible,
It can be made from a flat sheet and then bent to fit an arc. On the back side of the vibrator row 7, a sound absorbing material 13 made of a resin eye made of t% metal material is provided. Vibrator row 7, sound absorbing material 13
, the transducer array 8 is integrally constructed with adhesive. PZT has an acoustic impedance of approximately 35X10@soon//sec, PV
Since DF is about 4 X l O@yd sec, it is preferable that PZTl has λ/2 resonance and PVDF has λ/4 resonance. Ultrasonic waves from PZT pass through P'/DF to enter and exit. PVDF can also provide an effect similar to acoustic impedance matching compared to PZTK.

Ultrasonic waves to the rear of the PVDF are mostly reflected by the PZT and go out to the front. In this example, the first layer is 3.5 MHJ, the second layer
Although the layer is characterized by having each center frequency as 125 MH), it is also possible to use 0HIRF modulation, pseudorandom code modulation, etc. If a filter is used for discrimination during reception, both systems can be operated completely simultaneously. In this example, two sets of linearly arranged transducer arrays overlap at the same position and can scan the same fan-shaped scanning plane at different frequencies, so when used for human tissue, etc., the frequency characteristics of the tissue can be changed. It is suitable for performing tissue discrimination based on differences.

The example in Figure 2-) is made of PZT with a center frequency of 1! ! M
HJf)IIm! Array vibrator array layer 7, PVDF
More center frequency! 25 MH70 layer 10 of a linear array of transducer arrays is layered with 5 IN so as to form two mutually orthogonal fan-shaped scanning planes. Moreover, the transducer row 7
is arranged in the lower layer, and the transducer array 10 is arranged in the upper layer. 0 reflection 1 [11 is made of a material with the same thickness and acoustic impedance as PZ'l', and has the same characteristics as the intersection of the transducer arrays 7 and 10. It reflects the sound waves emitted backward from the KPVDF, and it is possible to use non-polarized PZT ceramics. The non-polarized plate 12 is made of a material having the same thickness and acoustic impedance as PVDF so that the sound waves emitted forward from the PZT spread over the entire surface of the transducer row 7 and at the intersection of the transducer rows 7 and 10. It is composed of a plate and is adhered to both left and right surfaces of the intersection of the transducer array 10. As a specific material for the non-polarized plate 12, it is convenient to use PVDF, which is the same as the vibrator array 1O, and is not polarized. According to this embodiment, two mutually orthogonal fan-shaped scanning planes are formed from one window,
It is also possible to scan completely simultaneously.

FIG. 3 is a diagram showing a specific example of the structure of a vibrator array that performs aperture control according to the present invention. In Fig. 3, 7 and 9 are transducer rows, 71.72.73... and 91.92.93.
... indicates a piezoelectric element, 90 indicates a ground electrode, a certain opening,
For example, the sound field formed by a disk shape with radius a is beam-shaped, and at short distances the beam radius is a, but at long distances it becomes a thin cone with an apex angle proportional to 1/λ (λ: wavelength). It spreads in a shape. Therefore, if you want to make the beam shape at a long distance the same at two frequencies, the aperture 1 can be made proportional to the wavelength λ.However, in this case, the beam shape at a short distance will be different. By defining the aperture so that most of this near sound field is in the front room, that is, inside the window 1, the beam in the object to be measured is mostly a far sound field, and therefore the entire measurement depth It is possible to achieve the same frequency-independent beam shape over the entire range. This is 11' in 411 when tissue discrimination is performed from the frequency dependence of the human body group Ik. In FIG. 3, vibrator rows 7 and 9 are made by linearly arranging unit elements to which piezoelectric elements 71 and 91 are bonded. The smoke type PZT piezoelectric element 71 is operated at wavelength λ1, but has electrodes on the front and back sides of the entire surface in the Y-axis direction, and is effective over the entire length WtK.

The piezoelectric element 91 is made of PVDF and is operated at a wavelength λ, Y
The length in the axial direction is W, and the length of the effectively opposing electrodes is W, which is WI/W*"λ1/λ.

The reason why the p-plane electrode of the piezoelectric element 91 of PYDF continues all the way to the bottom is to extract electrode signals. A unit element including the piezoelectric elements 71 and 91 is arranged, and the vibrator rows γ and 9 and the sound absorbing material 13 are integrated to form one #-shaped array. Further, the number of openings in the group to be selected in actual operation is four for the transducer row γ and four for the transducer row 9, and town/town=λI/λ.

shall be. In this way, a beam with a substantially rectangular cross section is formed, but in the far sound field, the beam shapes of both wavelengths λ and λ are the same. In the assembly diagram (1) of FIG. 3, for the purpose of explanation, the piezoelectric element 9 at point P (indicated in FIG. 3) of the piezoelectric element 91 is shown.
1) Although the upper part is shown to be removed, it should not actually be removed.

FIG. 4 is a diagram showing another specific example of the structure of a vibrator that performs aperture control according to the present invention v4. The transducer row 80I shown in FIG. 2(a)! It shows a method of changing the Y-axis direction opening of the mold array. 8' is a single organic piezoelectric plate such as PVDF, 80 is a ground electrode, and 81, 82, 83, . . . are signal electrodes. The ground electrode 80 has a width of W and is added to the entire length in the arc direction. When these electrodes are formed in advance and polarized by applying a voltage and heating, the ground electrode 80 and the signal electrode 81 are formed.
．． It is possible to make it so that only the portion facing 82, 83, etc. is polarized and exhibits a piezoelectric effect, and the rest does not exhibit a piezoelectric effect. The non-piezoelectric portion acts as a medium for transmitting and transmitting the ultrasonic waves from the piezoelectric element 71, 72, such as PZT.
．． This is effective in preventing the distribution of ultrasonic waves such as 72 in the Y-axis direction from being distorted by the piezoelectric portion of the PVDF having a width of W8.

Above, we have explained the main parts of the present invention, which realizes three-dimensional fan-shaped scanning using an array of 11 transducers. However, since phase control is not required compared to a phased array, the control circuit mainly consists of only selection switching. It's easy and cheap. Also, transformer
Since the arrangement surface of the juicer elements can be widened, various types of three-dimensional scanning, multi-frequency operation, etc. and their arrangement can be easily configured, and manufacturing is also easy and inexpensive.

On the other hand, a front chamber is required for the scanning St-intersection, and in order to eliminate the adverse effects of multiple reflections between the body surface and the transducer, k is the scanning line length I11 between the transducer and the window, and the front chamber is When the sound velocity is set to the indoor medium, the maximum measurement depth outside the window is m, and the sound velocity of the object to be measured is vt, the following conditions are required: 1, / *, ≧ m/h, which has the disadvantage of making the front chamber larger. . l
, for 6th year middle school students, 18 is at least the same as MU, and for the heart, etc., 1 = 19 CM, so the probe becomes longer. Also, if the scanning angle inside the body to be measured is 6, the scanning angle θ inside the front chamber is due to refraction, so s ln li 1 / s i n f) t = y
s / 1° becomes 1w, key is 2#, = 90@ then 2
θ, =90°, and along with Il, =18al, the size of the probe becomes a pilot flame type that cannot be used. This length l is suitable for practical use.

and front chamber scanning angle 20. It is absolutely necessary to minimize the angle (which gives the apex angle of the quadrangular pyramidal shape of the probe).

This request can be met by selecting a medium in the front room that is 11/s≦1.

This is clear from the above equations of Is and IIs.

11/ml, ≦172 is very preferable. Fluorine oil is an example of such a substance, and the town has about 1,500 living organisms.
For Noro c which is mlsec, 3M company F048, F'
072, FC75 etc. ν is 700.527.590m
/sec gives an excellent /11 ratio.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a front chamber K having one window, a plurality of linear arrays or a thousand-sided array of transducers are provided, and the scanning line formed by the transducer is near the window. By configuring the probe so that it crosses over almost one point, it is possible to form a plurality of different fan-shaped scanning planes from one contact point to the object to be measured, such as a living body, while keeping the probe in one posture. As a result, accurate, easy-to-handle, and inexpensive three-dimensional sector scanning can be realized.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention showing the relationship between the transducer arrangement, the scanning line intersection point, and the direction, where (a) shows an example of a plurality of 1IIi1 arrangements, and -) shows two orthogonal linear arrangements. The figure showing an example of , the stem) is a figure showing an example of matrix planar arrangement, and the hook is (
FIG. 2 is a cross-sectional view showing the probe structure in a), and FIG.
is a diagram showing an example of a linear array having a multilayer structure, (b) is a diagram showing an example of two orthogonal linear arrays having a multilayer structure,
FIG. 3 is a diagram showing a specific example of the structure of a transducer array that performs aperture control according to the present invention, and FIG. 4 is a diagram showing another specific example of the structure of a transducer array that performs aperture control according to the present invention. DESCRIPTION OF SYMBOLS 1... Window, 2-10... Vibrator row, 6... Vibrator surface, 8'... Piezoelectric plate, 11... Reflector plate, 12...
...Non-polarized plate, 13...Sound absorbing material, 14...Ante chamber, 7
1.72 and 73... piezoelectric element, 81.82 and 83...
・Signal electrode, 80 and 90...Earth electrode, 91.92
and 93...piezoelectric element. Patent Applicant Fujitsu Ltd. Representative Patent Attorney Kyotani 4 Departments 1 Figure (α) (C) Missing )Figure (C) (d) =:X2121 (α) (C)

Claims (1)

[Scope of Claims] α) An element array in which a plurality of ultrasonic transducer elements are arranged, a window through which ultrasonic waves enter and exit, and a front chamber configured between the element array and the window. an ultrasonic transmission medium filled with the ultrasonic transducer, and selectively operates the ultrasonic transducer array element as an aperture to focus the ultrasonic waves into a beam to transmit and receive the beam, and select some or all of the ultrasonic waves. In an ultrasonic scanning probe that scans an object to be measured circumscribed by the window with an ultrasonic beam, all the scanning lines selected from the element array intersect the window or a single point near the window. One feature is that the element array is configured in a multi-dimensional or composite manner so as to perform layered scanning through a point, and to perform at least two or more layered cross-sections and/or three-dimensional fan-shaped scanning. A three-dimensional eyebrow-shaped scanning probe. ■) A plurality of ultrasonic transducer elements are arranged in parallel to form one linear transducer row, and the plurality of linear transducer rows are arranged so that the intersection point of the scanning line is the center of one rate. Claim 1, characterized in that it has a pot metal element array arranged in parallel almost along a spherical surface.
The ultrasonic three-dimensional fan-shaped scanning probe described in . ) A plurality of ultrasonic transducer elements are arranged in parallel to form one line layer transducer array, and the I
I! Claim 1, characterized in that it has a compound element array in which a plurality of II transducer arrays are orthogonally arranged substantially along a spherical surface having a scanning intersection point as a center of one ratio. The ultrasonic three-dimensional fan-shaped scanning probe described in .葎) A patent characterized by having a multidimensional element array in which a plurality of ultrasonic transducer elements are arranged in a matrix in a flat plane INK roughly along a spherical surface with the intersection point of scanning lines as the center of one rate. An ultrasonic three-dimensional flat scanning probe according to claim 1. 6) IIm! with multiple element arrays! ) When the IIW transducer array is composed of multiple transducer arrays, at least two of each IIW transducer array are operated in an ultrasonic #scissor shape having mutually different frequencies or 4I increments. The ultrasonic three-dimensional type III scanning probe according to item 2 or 3. (6) A plurality of ultrasonic transducer elements are arranged in parallel to form one linear transducer array,
The arbitrary number of linear transducer arrays are arranged on one layer, and the 4Is are further superimposed and arranged almost along an arc or a spherical surface with the intersection point of the scanning lines as the center of the 1 ratio to form a composite element array. Configure. 1s each! ! ! ! 2. The ultrasonic three-dimensional layered scanning probe according to claim 1, wherein at least two of the lance juicer arrays are operated with ultrasonic waveforms having different frequencies or characteristics. ■ Ultrasonic transformer that makes up the element array. - A multi-layer ultrasonic trans-ducer element made by stacking a plurality of ultrasonic trans-ducer elements is used, and the ultra-blue wave trans-ducer element itself is An ultrasonic three-dimensional fan-shaped scanning probe according to any one of claims 1 to 511K. S) 1 [When several ultrasonic transducer elements are arranged multidimensionally or in one array, and an appropriate group of elements selected from among them converges and forms beams of different frequencies, each The apertures of the ultrasonic transducer elements themselves and/or the apertures of the selected elements as a group are adjusted based on the wavelength of the ultrasonic waves transmitted and received by each group, and the size of the near-field sound field is adjusted. 8. The ultrasonic three-dimensional fan-shaped scanning probe according to any one of claims 5 to 7, wherein the ultrasonic three-dimensional fan-shaped scanning probe is configured such that the portion is located within the front chamber. e) Claims 1 to 8 are characterized in that the front chamber is filled with an ultrasonic transmission medium whose speed of sound is approximately equal to or slower than the sound speed (-) of the object to be covered. The ultrasonic tertiary sector scanning probe described.