JPH01313043A - Electronic radial type ultrasonic endoscope - Google Patents

Abstract

PURPOSE:To obtain the high-resolution ultrasonic image of even the deep portion of an examined body by providing an oscillator array formed by arranging a plurality of ultrasonic oscillators in a conical annular form on the inserting end portion of an endoscope and projecting ultrasonic waves inward in the oscillator array from a selected ultrasonic oscillator group. CONSTITUTION:By interposing an ultrasonic-wave transmitting medium like water, etc., between an oscillator array 3 and an examined body, each ultrasonic oscillator group as a part of oscillator array 3 is selected in order to project ultrasonic waves so as to be converged inward in the oscillator array 3 obliquely in front of the inserting end face. The oscillator array 3 undergoes electronic radial scanning so as to receive the reflected waves of the examined body by the same oscillator groups, to obtain the ultrasonic image of the examined body. Thereby, ultrasonic waves projected from the ultrasonic wave oscillator groups which are selected in order to the inner direction in the array will not be incident into the opposite array portions, without causing undesirable damping due to the damper layer 5 of the array 3. Hence, by properly controlling the delay time of the driving signals fed to each oscillator 4, the converging position of ultrasonic waves can be optionally varied, obtaining a high-resolution ultrasonic image in observing the deep portion to say nothing of the shallow portion of an examined body.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electronic radial type ultrasonic endoscope. [Prior Art] As an apparatus for electronically radially scanning an ultrasonic beam, for example, Japanese Patent Laid-Open No. 55 -146065 Publication discloses that a plurality of ultrasonic transducers are arranged in an annular shape, and a part of the ultrasonic transducer groups of this transducer array are sequentially selected by an electronic scanner switch. A device in which ultrasonic waves are projected outward from a transducer array has been disclosed.

[Problem to be solved by the invention]

However, in the conventional electronic radial scanning method described above, the ultrasonic transducers are arranged in a ring shape and the ultrasonic waves are projected outward from the transducer array. This makes it difficult to focus ultrasound near the outer periphery of the esophagus, and as a result, when incorporated into an endoscope, the resolution of observation images of tube walls such as the esophagus is poor, and clear ultrasound tomographic images cannot be obtained. There is.

In order to solve such problems, the applicant first filed a patent application filed in 1983.
No. 1-295854, a matching member is filled inside an annular transducer array, and ultrasonic waves from sequentially selected ultrasonic transducer groups are directed to face the matching member and the selected ultrasonic transducer groups. We have developed an electronic radial scanning device that projects inward of the transducer array so that it passes through the transducer array and focuses on the outside of the transducer array.

According to this electronic radial scanning device, it is possible to focus ultrasound waves near the outer periphery of the annular transducer array, so when applied to an endoscope, the resolution of the observed image of the tube wall such as the esophagus can be improved. It has the advantage of being able to obtain clear ultrasonic tomographic images.

However, as a result of studies conducted by the present inventors, it has been found that the electronic radial scanning device previously developed by the present inventors has the following points to be improved.

In other words, each ultrasonic transducer that makes up the transducer array is provided with a damper layer to absorb undesired ultrasonic waves outward from the array. When the light passes through the vibrator, it is undesirably attenuated by the damper layer, which conversely reduces the resolution of the deep observation image.

This invention was made with attention to these problems, and allows ultrasonic waves to be transmitted and received without causing undesired attenuation. Therefore, it is possible to transmit and receive ultrasonic waves without causing undesired attenuation, and therefore, it is possible to transmit and receive ultrasonic waves with high resolution ultrasonic waves even when observing not only shallow parts but also deep parts of a subject. It is an object of the present invention to provide an electronic radial type ultrasonic endoscope that is appropriately configured to obtain a sonic image.

[Means and effects for solving the problem] In order to achieve the above object, the present invention provides a transducer array in which a plurality of ultrasonic transducers are arranged in a conical ring shape at the insertion tip of an endoscope. The ultrasonic transducer array is configured to sequentially select some ultrasonic transducer groups in the transducer array and project ultrasonic waves from the selected ultrasonic transducer groups toward the inside of the transducer array.

〔Example〕

FIG. 1 shows a first embodiment of the invention. This ultrasonic endoscope 1 is a side-viewing endoscope in which a transducer array 3 is provided at the insertion tip 2 of the endoscope.

The transducer array 3 has a plurality of ultrasonic transducers 4 arranged in a conical ring shape, and has a damper layer 5 on its outer circumference that absorbs outward ultrasonic waves, and on its inner circumference that absorbs the projected ultrasonic waves in a planar shape. An ultrasonic lens 6 converging in the (slicing direction) is provided to prevent the ultrasonic waves projected from each ultrasonic transducer 4 toward the inside of the array from entering the opposing ultrasonic transducer 4. The child array 3 is attached to the distal end surface of the insertion tip 2 so that its center axis coincides with the insertion center axis of the insertion tip 2, and the diameter becomes larger toward the tip. Also,
A drive line 7 including a ground line and a signal line for driving each ultrasonic transducer 2 extends through the interior of the endoscope and is connected to a drive device (not shown) provided outside the endoscope. Note that a cover glass 8 is attached to the insertion tip 2.
, objective lens 9, prism 10 and image guide 1
1 is provided, as well as a known side-view type observation optical system having
A known side-view illumination optical system including a light guide (not shown) is provided.

In this way, in this embodiment, an ultrasound transmission medium such as water is interposed between the transducer array 3 and the subject, and some ultrasound transducer groups in the transducer array 3 are sequentially selected. The transducer array is configured such that the ultrasonic waves are projected inside the transducer array 3 so as to be focused obliquely in front of the insertion tip surface, and the reflected waves from the subject are received by the same transducer group. 3 is subjected to electronic radial scanning to obtain an ultrasound image of the subject. here,
The selection of some ultrasonic transducer groups in radial scanning is
A predetermined number of adjacent transducers 4 may be selected sequentially without duplication, or a predetermined number of transducers 4 may be selected sequentially without duplication.
You may select them in duplicate while shifting them.

According to this embodiment, since the ultrasonic waves projected in the array inward from the sequentially selected ultrasonic transducer groups do not enter the opposing array portions, undesirable attenuation by the damper layer 5 of the array 3 is prevented. does not occur. Therefore, by appropriately adjusting the delay time of the drive signal supplied to each transducer 4 in the group of ultrasonic transducers that are sequentially selected, the focusing position of the ultrasonic waves can be changed arbitrarily. High-resolution ultrasound images can be obtained even when observing deep parts.

FIG. 2 shows a second embodiment of the invention. In this embodiment, the ultrasonic lens 6 is removed from the inner periphery of the transducer array 3 to provide a conical ring-shaped ultrasonic prism 15, and the prism 15 reflects the ultrasonic waves projected inside the array to the outside of the array. As a result, the plane perpendicular to the insertion axis of the endoscope is scanned radially, and the observation direction by the ultrasound and the viewing direction by the observation optical system are made to match in the cross section.The other configuration is as follows. This is the same as the first embodiment. The ultrasonic prism 15 is designed to have the same effect as the ultrasonic lens 6 shown in FIG.

According to this embodiment, there is an advantage that the area to be observed by ultrasonic waves can be observed using an optical system, and there is also an advantage that the ultrasonic waves can be focused deeper into the subject.

FIG. 3 shows a third embodiment of the invention. This embodiment is based on the conical annular ultrasonic prism 15 of the second embodiment.
Instead of
It is filled with a matching member 16 such as iNbO3, and the other configurations are the same as in the second embodiment. In this embodiment as well, the matching member 16 is made to have the function of the ultrasonic lens 6 shown in FIG. 1. By providing the matching member 16 in this manner, attenuation of ultrasonic waves can be effectively prevented, so that resolution can be further improved.

Note that in the above embodiments, the observation optical system was of a side-viewing type;
Each of these can also be of a direct view type or a perspective type. An example thereof 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. The endoscope is made into a direct viewing type by holding the lens 9 and the incident part # of the image guide 11, as well as holding an illumination optical system (not shown).

Furthermore, the observation optical type is not limited to one that uses an image guide, but may also be a so-called electronic scope that uses a solid-state imaging device such as a COD.

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

In this way, using the common signal line 22, by selecting the ground line 23 with the switch 25, the transducer array 3 is driven to radially scan the object, and by selecting the ground line 24, the linear array 21 to linearly scan the subject.

In this way, the signal line 22 of the transducer array 3 and the linear array 21 is made common to the ground lines 23 and 2.
If the transducer array 3 and the linear array 21 are selected by switching and connecting 4, the signal line 22 will be sufficient for one array, so it will be easier to insert the endoscope than when the signal line 22 is provided independently. The diameter of the part can be made smaller, thus reducing patient pain. Note that the technique of sharing the signal line in this way is based on the linear array 21 as described later.
The present invention can be effectively applied to cases where an annular array or convex array is used instead of the oscillator array 3, and can also be effectively applied when three or more independent arrays including the transducer array 3 are used.

Modifications of this invention will be described below.

FIG. 6 shows the configuration of a vibrator array that performs radial scanning. This transducer array 27 is configured in an annular shape so as to project ultrasonic waves outward. The ultrasonic transducer 28 constituting the transducer array 27 is formed of a polymer material (for example, PVDF) or a composite piezoelectric material in a ring shape, and the ground electrode 31 is divided into a plurality of parts and each of the divided ground electrodes 31 is The same 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 ground electrode 31 is associated with three signal electrodes 32, so that the vibrator array 27 has a total of 12 vibration surfaces. A signal electrode 32 corresponding to each ground electrode 31 is commonly connected to three signal lines 33, and four ground electrodes 31 are connected to the switch 3.
4 to enable selective connection to a common ground line 35. In this way, the common signal line 33
Using the switch 34, the earth electrodes 31 are sequentially selected and the transducer array 27 is radially scanned. Therefore, if this transducer array 27 is used, the number of drive lines can be extremely reduced compared to the case where a signal line and a ground line are provided for each ultrasonic vibration surface.
The diameter of the endoscope insertion portion can be reduced, reducing patient pain during insertion.

The transducer array 27 shown in FIG. 6 can be provided on the outer periphery of the insertion tip 2 instead of the linear array 21 shown in FIG. 5, and can also be used alone. Furthermore, by configuring the transducer array 3 in a conical ring shape so as to project ultrasonic waves inward, it can be used in place of the transducer array 3 shown in the first to fifth embodiments.

FIGS. 7A and 7B are a side view and a front view showing the configuration of a vibrator array that performs radial scanning.

This transducer array 37 has each ultrasonic transducer 38 formed into a concave shape in a direction perpendicular to the radial scanning direction. Therefore, according to this vibrator array 37,
Since the ultrasonic waves projected from each ultrasonic transducer 38 can be focused even if they are on the right in the slice direction without using a separate ultrasonic lens, the resolution can be further improved with a simple configuration.

This transducer array 37 can be used, for example, by being provided on the outer periphery of the endoscope insertion tip 2 in the first to fifth embodiments, or can be used alone.

FIG. 8 shows another example of how the transducer array 37 shown in FIGS. 7A and 7A is used. In this example, the transducer array 37 is held within a tube 40 made of stretchable silicone rubber, and a tube 41 is placed within the tube 40.
The curvature of the tube 40 at the portion facing the ultrasonic projection surface of the vibrator 37 can be changed by introducing and removing an ultrasonic transmission medium 42 such as water through the tube.

With this configuration, by changing the curvature of the tube 40, it is possible to achieve dynamic focusing that arbitrarily changes the focusing position of the ultrasound waves in the slice direction. Ultrasound images can be obtained.

The ultrasonic diagnostic device having such a configuration can be provided, for example, in the endoscope insertion tip 2 in the first to fifth embodiments, and particularly in the configuration shown in FIG. It can also be provided so as to protrude forward of the insertion tip 2 through the central part of the insertion tip 2.

FIGS. 9A to 9E show configurations of various vibrator arrays. These transducer arrays are made by combining ultrasonic transducers with a 1-3 type composite material made by regularly arranging ceramic rods and filling them with a polymer material, or by porously firing piezoelectric ceramics. 9A shows an annular vibrator array 45, and FIG. 9B shows an annular vibrator array with each vibrator projecting outward. Similarly to FIGS. 7A and 7B, FIG. 9C shows an annular transducer array 47 that is concave inward so that each transducer can be focused in the slice direction. In addition, the ninth diagram shows a pie-brane structure in which a convex array 48 that projects ultrasonic waves outward and a convex array 49 that projects ultrasonic waves inward are arranged so that their scanning planes are perpendicular to each other. FIG. 9E shows a pie-brane structure in which a convex array 50 that projects ultrasonic waves outward and a linear array 51 are similarly arranged so that their scanning planes are perpendicular to each other.

If the transducer array is constructed using a composite piezoelectric material in this way, it is flexible, so it can be easily manufactured with any shape and curvature, and the electrical impedance of the transducer array can be reduced, so it can be used in the transmitter circuit. It can also be easily matched with

The transducer array shown in FIGS. 9A to 9E can be provided at the endoscope insertion tip 2 in, for example, the first to fifth embodiments, and in particular, in the configuration shown in FIG. 2, the transducer array shown in FIG. Similarly, it can also be provided so as to protrude in front of the insertion tip 2 through the center of the conical annular ultrasonic prism 15.

FIGS. 10A and 10B show an ultrasound endoscope using a convex array. This ultrasound endoscope 55 is
A convex array 57 that projects ultrasound inward to the insertion tip 56 of the endoscope so as to be orthogonal to the insertion center axis.
A mirror 58 for selectively reflecting the ultrasonic waves from the convex array 57 forward is provided so as to be movable in the direction of the insertion axis. A transparent membrane 59 is provided at the insertion tip 56 so as to cover the convex 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 movable body 61 that holds the observation and illumination optical system, and by operating this movable body 61 in the endoscope operation section, the mirror 58 is moved in and out of the ultrasonic path of the convex array 57. do it like this.

In this way, the subject 62 can be directly observed endoscopically through the mirror 58, and the mirror 58 can be retracted from the ultrasound path of the convex array 57 as shown in FIG. By inserting the mirror 58 into the ultrasonic path of the convex array 57 as shown in FIG.
Ultrasonic images of planes intersecting the scanning plane in the case of Figure A are obtained respectively. As described above, the ultrasound endoscope 55 has a simple configuration in which one convex array 57 is used and the mirror 58 is selectively moved in and out of the ultrasound path, and ultrasound images of planes that intersect with each other can be obtained. can be obtained.

The ultrasonic endoscope 55 shown in FIGS. 10A and 10B is
In the embodiment, the insertion tip 2 can be provided at the endoscope insertion tip 2, and in particular, in the configuration shown in FIG. It can also be provided so as to protrude in front of the. Further, when incorporated in the first to fifth embodiments in this way, it is not necessarily necessary to provide the observation and illumination optical system in the movable body 61.

Note that this invention is not limited to the above-mentioned example, and can be modified or changed in many ways. For example, the first
When using a convex array 65 and a linear array 66 as shown in FIGS. 1A and 1B, the holding members 67 and 68 that hold them are mechanically rotatable,
The viewing angle of the ultrasound image by the convex array 65 and the linear array 66 can also be set to 360°. Furthermore, in the first to fifth embodiments, the transducer array 3 was mounted so that the ultrasonic waves were projected from the transducer array 3 inward of the array and in front of the tip insertion section 2; As shown in Figures A and B, the transducer array 3 is mounted so as to project ultrasound inside the array and behind the tip insertion section 2 via the conical annular ultrasound prism 15 and the matching member 16. You can also do that.

〔Effect of the invention〕

As described above, according to the present invention, the transducer array is formed into a conical ring shape and the ultrasonic waves are projected inward, so that the ultrasonic waves do not pass through the opposing array part. It can be projected onto the subject. Therefore, ultrasonic waves can be transmitted and received without causing undesired attenuation, so that high-resolution ultrasonic images can be obtained not only in shallow areas but also in deep areas of the subject.

[Brief explanation of the drawing]

Fig. 1 shows a first embodiment of the invention, Fig. 2 shows a second embodiment, Fig. 3 shows a third embodiment, and Fig. 4 shows a fourth embodiment. FIG. 5 is a diagram similarly showing the fifth embodiment, FIG. 6, FIG. 7 A, B, FIG. 8, and FIG. 9 A-E. Figure 10 A, B, Figure 11 A, B and Figure 12 A
, B are diagrams for explaining the present invention in detail. 1... Ultrasound endoscope 2... Insertion tip 3...
- Transducer array 4... Ultrasonic transducer... Damper layer 6... Ultrasonic lens 7... Drive line 8... Cover glass 9... Objective lens
IO...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 patent applicant Olympus Optical Industry Co., Ltd. --J

Q Figure 6 Figure 9 A B CD Section To Figure 11 A Also

Claims (1)

[Claims] 1. A transducer array consisting of a plurality of ultrasonic transducers arranged in a conical ring is provided at the insertion tip of the endoscope, and a part of the ultrasonic transducer groups in this transducer array are sequentially selected. An electronic radial type ultrasonic endoscope, characterized in that the electronic radial type ultrasonic endoscope is configured to project ultrasonic waves from a group of ultrasonic transducers inward of the transducer array.