JP2718944B2 - Electronic radial ultrasonic endoscope - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electronic radial ultrasonic endoscope.

[Conventional technology]

As a method for electronically radially scanning an ultrasonic beam, for example, Japanese Patent Application Laid-Open No. Sho 55-146065 discloses that a plurality of ultrasonic transducers are arranged in a ring shape, and a part of the ultrasonic transducer group of this transducer array. Are sequentially selected with the electronic scanner switch,
There is disclosed one in which ultrasonic waves are projected from a selected ultrasonic transducer group toward the outside of a transducer array.

[Problems to be solved by the invention]

However, in the above-described conventional electronic radial scan method, the ultrasonic transducers are arranged in a ring shape and the ultrasonic waves are projected toward the outside of the transducer array. It becomes difficult to focus ultrasonic waves near the outer circumference of the esophagus, which results in poor resolution of observation images of tube walls such as the esophagus and the inability to obtain clear ultrasonic tomographic images when incorporated into an endoscope. There is.

In order to solve such a problem, the applicant of the present application
In Japanese Patent Application Laid-Open No. 61-295854 (JP-A-63-147443), a matching member is filled inside an annular transducer array,
The vibrator is configured to transmit the ultrasonic waves from the sequentially selected ultrasonic vibrator group through the matching member and the vibrator array portion facing the selected ultrasonic vibrator group to be focused outside the vibrator array. An electronic radial scanning device was designed to project toward the inside of the array.

According to this electronic radial scanning device, since the ultrasonic waves can be focused near the outer periphery of the annular transducer array, when applied to an endoscope, the resolution of an observation image of a tube wall such as an esophagus can be increased. There is an advantage that a clear ultrasonic tomographic image can be obtained.

However, as a result of the study by the present inventors, it has been found that the above-described electronic radial scanning device developed earlier by the present applicant has the following points to be improved.

That is, since each ultrasonic transducer constituting the transducer array is provided with a damper layer for absorbing undesired ultrasonic waves to the outside of the array, the ultrasonic waves are transmitted and received during the transmission and reception of the ultrasonic waves. When the light passes through the vibrator, it is undesirably attenuated by the damper layer, and consequently, the resolution of a deep observation image is reduced.

The present invention has been made in view of such a problem. Even when ultrasonic waves are projected outward with respect to the insertion center axis of the endoscope, the ultrasonic waves are focused near the outer periphery of the endoscope. When projecting inward, ultrasonic waves can be transmitted and received without causing unwanted attenuation, and therefore, when projecting outward and inward, shallow portions of the subject It is another object of the present invention to provide an electronic radial ultrasonic endoscope appropriately configured to obtain a high-resolution ultrasonic image in observation of a deep part.

[Means and actions for solving the problem]

In order to achieve the above object, according to the present invention, in an electronic radial ultrasonic endoscope, a plurality of ultrasonic transducers are sequentially arranged in a circumferential direction of the insertion distal end portion while tilting a plurality of ultrasonic transducers at the insertion distal end portion of the endoscope. A conical ring-shaped transducer array consisting of
It is characterized in that a part of the ultrasonic vibrator group of the vibrator array is sequentially selected, and ultrasonic waves are projected from the selected ultrasonic vibrator group.

〔Example〕

FIG. 1 shows a first embodiment of the present invention. The ultrasonic endoscope 1 has a transducer array 3 provided at an insertion distal end portion 2 of a side-view type endoscope. The vibrator array 3 has a plurality of ultrasonic vibrators 4 arranged in a conical ring while being inclined, and a damper layer 5 for absorbing outward ultrasonic waves is provided on an outer periphery thereof, and an ultrasonic wave projected on an inner periphery thereof. Are provided respectively with an ultrasonic lens 6 for converging in a plane (slice direction),
Ultrasonic waves projected from the respective ultrasonic transducers 4 toward the central axis in the array inward direction are configured not to be incident on the opposed ultrasonic transducers 4. 2 is mounted on the distal end surface of the insertion distal end portion 2 so as to have a larger diameter in the forward direction so as to coincide with the central axis of insertion. A drive line 7 including an earth line and a signal line for driving each ultrasonic transducer 2 extends through the inside of the endoscope and is connected to a drive device (not shown) provided outside the endoscope. A well-known side-viewing observation optical system having a cover glass 8, an objective lens 9, a prism 10, and an image guide 11 is provided at the insertion tip 2, and a well-known side-viewing type having a light guide (not shown) is provided. An illumination optical system is provided.

In this manner, in this embodiment, a part of the ultrasonic transducer group of the transducer array 3 is sequentially selected by interposing the ultrasonic transmission medium such as water between the transducer array 3 and the subject. Ultrasonic waves are projected inside the vibrator array 3 so as to be focused obliquely forward of the insertion distal end surface, and the vibrator array is configured to receive reflected waves from the subject with the same vibrator group. 3 is subjected to electronic radial scanning to obtain an ultrasonic image of the subject. Here, in the selection of a part of the ultrasonic transducer groups in the radial scanning, a predetermined number of adjacent transducers 4 may be sequentially selected without overlapping each transducer 4, or a predetermined number of transducers may be selected. The child 4 may be selected sequentially while being shifted while being shifted.

According to this embodiment, since the ultrasonic waves projected in the array direction from the sequentially selected ultrasonic transducer group do not enter the opposing array portion, the damper layer 5 of the array 3
Does not cause unwanted attenuation. Therefore, by appropriately adjusting the delay time of the drive signal supplied to each transducer 4 of the ultrasonic transducer group to be sequentially selected, the focusing position of the ultrasound can be arbitrarily changed, so that not only the shallow portion of the subject but also the shallow portion of the subject can be changed. A high-resolution ultrasonic image can be obtained even when observing a deep part.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, the ultrasonic lens 6 is detached from the inner periphery of the vibrator array 3 and a conical annular ultrasonic prism 15 is provided, and the ultrasonic waves projected toward the center axis inside the array by the prism 15 are arrayed. Reflected outward, thereby radially scanning a plane orthogonal to the endoscope insertion axis, so that the observation direction by ultrasound and the viewing direction by the observation optical system match in cross section, Other configurations are the same as in the first embodiment. The ultrasonic prism 15 has the same function as the ultrasonic lens 6 shown in FIG. According to this embodiment, there is an advantage that the observation site by the ultrasonic wave can be observed by the optical system, and there is an advantage that the ultrasonic wave can be focused on a deeper part of the subject.

FIG. 3 shows a third embodiment of the present invention. In this embodiment, the conical annular ultrasonic prism 15 of the second embodiment is used.
In place of the above, Li that transmits ultrasonic waves
It is filled with a matching member 16 such as NbO ₃ , and the other configuration is the same as that of the second embodiment. It should be noted that also in this embodiment, the ultrasonic lens 6 shown in FIG.
To have the effect of. By providing the matching member 16 in this manner, the attenuation of the ultrasonic waves can be favorably prevented, so that the resolution can be further improved.

In the above embodiment, the observation optical system is of a side-view type, but it may be of a direct-view type or a perspective type. An example is shown in FIG. 4 as a fourth embodiment. In the ultrasonic endoscope 1 shown in FIG. 4, an optical system holding member 17 is provided on the inner periphery of an ultrasonic prism 15 in the second embodiment, and a cover glass 8 and an objective which constitute an observation optical system are provided on the holding member 17. The endoscope is a direct-view type while holding the lens 9 and the incident end of the image guide 11 and holding an illumination optical system (not shown).

Further, the observation optical type is not limited to the one using an image guide, but may be a so-called electronic scope using a solid-state imaging device such as a CCD.

FIG. 5 shows a fifth embodiment of the present invention. This embodiment is a linear array in which the ultrasonic endoscope 1 shown in the first to fourth embodiments has a plurality of ultrasonic transducers 20 arranged linearly in the insertion distal end portion 2 along the insertion axis direction. 21 is added, and the linear array 21 and the vibrator array 3 for performing radial scanning are driven by a common signal line 22. Therefore, each of the ultrasonic transducers 4 of the transducer array 3 and each of the ultrasonic transducers 20 of the linear array 21 are connected to a corresponding common signal line 22, and the ground of the transducer array 3 is connected to a common ground line. At 23, the grounds of the linear array 21 are connected to a common ground line 24, respectively, so that these ground lines 23 and 24 can be selected by a switch 25.

In this manner, by using the common signal line 22 and selecting the earth line 23 by the switch 25, the vibrator array 3 is driven to radially scan the subject, and by selecting the earth line 24, the linear array is selected. The object 21 is driven to linearly scan the subject.

As described above, by selecting and connecting the transducer array 3 and the linear array 21 by switching and connecting the ground lines 23 and 24 while sharing the signal line 22 of the transducer array 3 and the linear array 21, Since only one array is required for 22, the diameter of the endoscope insertion portion can be reduced as compared with the case where the array is provided independently, so that the pain of the patient can be reduced. The technique of sharing the signal lines in this manner can be effectively applied to the case where an annular array or a convex array is used instead of the linear array 21 as described later, and three techniques including the transducer array 3 are used. The present invention can be effectively applied to the case where the independent array is used.

 Hereinafter, modified examples of the present invention will be described.

FIG. 6 shows the structure of a transducer array for performing radial scanning. The vibrator array 27 is formed in a ring shape so as to project ultrasonic waves outward. The ultrasonic vibrator 28 constituting the vibrator array 27 is formed in an annular shape using a polymer material (for example, PVDF) or a composite piezoelectric material, and the ground electrode 31 is divided into a plurality of parts. An equal number of signal electrodes 32 are associated with each other. That is, in FIG. 6, the ground electrode 31 is divided into four parts, and each of the ground electrodes 31 is made to correspond to three signal electrodes 32, so that the vibrator array 27 has a total of twelve vibrating surfaces. The signal electrodes 32 corresponding to the respective ground electrodes 31 are commonly connected to three signal lines 33, and the four ground electrodes 31 are selectively connected to a common ground line 35 via a switch 34. To get. In this manner, the ground electrode 31 is sequentially selected by the switch 34 using the common signal line 33, and the transducer array 27 is radially scanned. Therefore, by using the transducer array 27, the number of drive lines can be extremely reduced as compared with the case where a signal line and a ground line are provided for each ultrasonic vibration surface, and the diameter of the endoscope insertion portion can be reduced. In addition, the pain of the patient when inserting can be reduced.

The vibrator array 27 shown in FIG. 6 can be used by being provided on the outer periphery of the insertion distal end portion 2 instead of the linear array 21 shown in FIG. 5, or can be used alone.
Further, by forming a conical annular shape so as to project ultrasonic waves inward, the transducer array 3 shown in the first to fifth embodiments can be formed.
Can be used instead of

FIGS. 7A and 7B are a side view and a front view showing the configuration of a transducer array for performing radial scanning. In this transducer array 37, each ultrasonic transducer 38 is formed in a concave shape in a direction orthogonal to the radial scanning direction. Therefore, according to the transducer array 37, the ultrasonic waves projected from each of the ultrasonic transducers 38 can be focused also in the slice direction without using an ultrasonic lens separately, so that the resolution is further improved with a simple configuration. it can. This transducer array 37
Is, for example, the endoscope insertion tip 2 in the first to fifth embodiments.
Can be used by being provided on the outer periphery, or can be used alone.

FIG. 8 shows another example of the mode of use of the vibrator array 37 shown in FIGS. 7A and 7B. In this example, the vibrator array 37 is held in a tube 40 made of, for example, an elastic cylinder rubber, and an ultrasonic transmission medium 42 such as water is put into and taken out of the tube 40 through a tube 41 to vibrate the vibrator. The curvature of the tube 40 at the portion of the probe 37 facing the ultrasonic projection surface can be changed. According to this configuration, by changing the curvature of the tube 40, dynamic focus in which the focus position of the ultrasonic wave is arbitrarily changed in the slice direction can be realized, so that the resolution is always high even in the shallow part and the deep part of the subject. An ultrasonic image can be obtained.

The ultrasonic diagnostic apparatus having such a configuration includes, for example, first to fifth ultrasonic diagnostic apparatuses.
In the embodiment, it can be provided at the insertion end portion 2 of the endoscope, and particularly in the configuration shown in FIG. 2, it can be provided so as to protrude forward of the insertion end portion 2 through the central portion of the conical annular ultrasonic prism 15. it can.

9A to 9E show configurations of various transducer arrays. In these vibrator arrays, an ultrasonic vibrator was formed by regularly arranging ceramic rods, filling a polymer material into a composite, and firing a 1-3 type composite material or a piezoelectric ceramic in a porous manner. FIG. 9A shows a ring-shaped vibrator array 45 made of a composite piezoelectric material such as a material.
9B shows an annular transducer array 46 in which each transducer is projected outward, and FIG. 9C shows each transducer in the slice direction as in FIGS. 7A and 7B. Each of the ring-shaped transducer arrays 47 is formed inwardly concave so as to be focused. FIG. 9D shows a biplanar structure in which a convex array 48 for projecting ultrasonic waves outward and a convex array 49 for projecting ultrasonic waves inward are arranged so that the scanning planes are orthogonal to each other. FIG. 9E shows a biplanar structure in which a convex array 50 and a linear array 51 for projecting ultrasonic waves outward are similarly arranged so that the scanning planes are orthogonal to each other.

If the vibrator array is made of a composite piezoelectric material in this way, it has flexibility and can easily be made with any shape and curvature, and its electrical input impedance can be reduced, so that the transmission circuit Can easily be matched.

The transducer arrays shown in FIGS. 9A to 9E are, for example, first to fifth transducers.
In the embodiment, it can be provided at the insertion end portion 2 of the endoscope, and particularly in the configuration shown in FIG. 2, similarly to the case of FIG. May be provided so as to protrude forward.

FIGS. 10A and 10B show an ultrasonic endoscope using a convex array. The ultrasonic endoscope 55 is provided with a convex array 57 for projecting ultrasonic waves inward so as to be orthogonal to an insertion center axis at an insertion distal end portion 56 of the endoscope, and an ultrasonic wave from the convex array 57. A mirror 58 for selectively reflecting sound waves forward is provided movably in the insertion axis direction. A transparent film 59 is provided on the insertion tip 56 so as to cover the compex array 57 so that an ultrasonic transmission medium 60 such as water can be accommodated therein. The mirror 58 is attached to the tip of a moving body 61 holding an observation and illumination optical system, and the mirror 58 is moved into and out of the ultrasonic path of the convex array 57 by operating the moving body 61 in an endoscope operation unit. To do. In this way, the subject 62 is directly observed endoscopically through the mirror 58, and the mirror 58 is retracted from the ultrasonic path of the convex array 57 as shown in FIG. The ultrasonic image of the plane intersecting the scanning plane in the case of FIG. 10A by inserting the mirror 58 into the ultrasonic path of the convex array 57 as shown in FIG. To get. As described above, according to the ultrasonic endoscope 55, an ultrasonic image of planes intersecting with each other can be obtained with a simple configuration in which one convex array 57 is used, and the mirror 58 is selectively moved in and out of the ultrasonic path. Can be obtained.

The ultrasonic endoscope 55 shown in FIGS. 10A and 10B can be provided at the endoscope insertion distal end portion 2 in the first to fifth embodiments, and particularly in the configuration shown in FIG. Similarly to the above, it may be provided to project forward of the insertion tip 2 through the center of the conical annular ultrasonic prism 15.
Further, when the moving body 61 is incorporated in the first to fifth embodiments, it is not always necessary to provide an observation and illumination optical system in the moving body 61.

It should be noted that the present invention is not limited to the above-described example, and various modifications or changes are possible. For example,
11 When the convex array 65 and the linear array 66 are used as shown in FIGS. A and B, the holding members 67 and 68 for holding the convex array are mechanically rotatable, and the ultrasonic image by the convex array 65 and the linear array 66 is used. The viewing angle can be 360 °. In the first to fifth embodiments, the vibrator array 3 is mounted so that ultrasonic waves are projected from the vibrator array 3 inside the array and in front of the distal end insertion portion 2. And B, a conical annular ultrasonic prism 15 and a matching member
The transducer array 3 can be mounted so as to project ultrasonic waves inward through the portion 16 and behind the distal end insertion portion 2.

〔The invention's effect〕

As described above, according to the present invention, a conical annular vibrator array in which a plurality of ultrasonic vibrators are sequentially arranged in the circumferential direction while being inclined is provided at the insertion end of the endoscope. Since a part of the ultrasonic transducer group of the transducer array is sequentially selected and the ultrasonic waves are projected from the selected ultrasonic transducer group, the ultrasonic waves are directed outward with respect to the insertion center axis of the endoscope. When projecting toward the endoscope, it can be focused near the outer periphery of the endoscope, and when projecting toward the inside, it does not transmit through the opposing array portion, and thus undesirably attenuates ultrasonic waves. Therefore, a high-resolution ultrasonic image can be obtained when observing not only the shallow part but also the deep part of the subject, regardless of whether the object is projected outward or inward.

[Brief description of the drawings]

1 is a diagram showing a first embodiment of the present invention, FIG. 2 is a diagram showing a second embodiment, FIG. 3 is a diagram showing a third embodiment, and FIG. 4 is a fourth embodiment. FIG. 5 is a view showing the fifth embodiment, FIG. 6, FIG. 7A, B, FIG. 8, FIG. 9A-E, FIG.
B, FIGS. 11A and 12B, and FIGS. 12A and 12B are diagrams for explaining modifications of the present invention. DESCRIPTION OF SYMBOLS 1 ... Ultrasonic endoscope, 2 ... Insertion tip part 3 ... Transducer array, 4 ... Ultrasonic transducer 5 ... Damper layer, 6 ... Ultrasonic lens 7 ... Drive line, 8 ... Cover glass 9 Objective lens 10 Prism 11 Image guide 15 Ultrasonic prism 16 Matching member 17 Optical system holding member 20 Ultrasonic transducer 21 Linear array 22 ... signal line, 23, 24 ... earth line 25 ... switch

 ────────────────────────────────────────────────── ─── Continuing the front page (72) Inventor Shinichi Imade 2-4-2-3 Hatagaya, Shibuya-ku, Tokyo Inside O-Limpus Optical Industry Co., Ltd. (72) Inventor Takashi Tsukaya 2-43-2 Hatagaya, Shibuya-ku, Tokyo No. Oh-Limpus Optical Co., Ltd. (72) Inventor Takeshi Yokoi 2-43-2 Hatagaya, Shibuya-ku, Tokyo In-Olympus Optical Industry Co., Ltd. (72) Kuniaki Ue 2-43-2, Hatagaya, Shibuya-ku, Tokyo No. Olympus Optical Co., Ltd. (72) Inventor Masaaki Hayashi 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-limpus Optical Co., Ltd. (56) References JP-A-58-133240 (JP, A) 1987-152441 (JP, A)

Claims (1)

(57) [Claims] 1. A conical ring-shaped vibrator array which is sequentially arranged in the circumferential direction of the insertion distal end while tilting a plurality of ultrasonic vibrators at an insertion distal end of an endoscope. An electronic radial type ultrasonic endoscope wherein a part of ultrasonic transducer groups is sequentially selected and an ultrasonic wave is projected from the selected ultrasonic transducer group.