JP3671725B2 - Ultrasonic probe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic probe that is inserted into a body cavity or the like and performs ultrasonic inspection by rotationally driving an ultrasonic transducer, and in particular, an ultrasonic wave that prevents electrostatic noise from being taken into the cable. It relates to the probe.
[0002]
[Prior art]
Ultrasound inspection devices include those that transmit ultrasonic signals from the outside of the body epidermis into the body, and those that are guided into the body cavity to transmit and receive ultrasound from the closest location such as the affected area from the inner wall of the body cavity There is something configured to do. There is an ultrasonic endoscope as a representative example of an intracorporeal ultrasonic inspection apparatus, and a small-diameter ultrasonic probe is configured separately from the endoscope, and this ultrasonic probe is used as an endoscope treatment. There is also an ultrasonic probe that is inserted into the body using the instrument insertion channel as a guide means, that is, inserted transendoscopically.
[0003]
In any case, in the ultrasonic inspection apparatus inserted into the body cavity, while the ultrasonic transducer is rotationally driven, an ultrasonic pulse is transmitted toward the body at a predetermined angle and reflected from a tomographic part in the body. Some are configured to perform so-called mechanical radial ultrasonic scanning in which echoes are acquired. In performing mechanical radial ultrasonic scanning, there is one configured to rotationally drive an ultrasonic transducer by remote operation. This operation is generally performed using a control cable. The control cable has a structure in which a flexible shaft is inserted into a flexible sleeve, an ultrasonic vibrator is connected to the distal end of the flexible shaft, and a driving means such as a motor is connected to the proximal end portion. It is. When the flexible shaft is driven to rotate around the axis within the sleeve by this driving means, this rotation is transmitted to the tip, and the ultrasonic transducer rotates. A cable is connected to apply a drive signal to the ultrasonic transducer and to extract a reflected echo signal received by the ultrasonic transducer to the outside. This cable is connected to the ultrasonic observation apparatus through a rotary connector or the like in the middle, and the ultrasonic observation apparatus processes ultrasonic signals such as an ultrasonic transmission / reception circuit and a scan converter. A circuit for generating an ultrasonic image is provided.
[0004]
The ultrasonic reception signal is a very weak signal. Therefore, when transmitting this weak ultrasonic reception signal to the ultrasonic observation apparatus, even if a small amount of noise is captured, the image quality of the ultrasonic image is greatly affected. Arise. Whether it is an ultrasonic endoscope or an ultrasonic probe inserted transendoscopically, in the case of an electronic endoscope using a solid-state imaging device as an observation means of the endoscope, an insertion portion A cable for transmitting / receiving a signal to / from a solid-state image pickup device attached to the tip of the solid-state image pickup device is connected. The solid-state image pickup device is driven via this cable, and a video signal from the solid-state image pickup device is transmitted to the processor. Accordingly, since the cable connected to the solid-state imaging device is inserted into the insertion portion together with the cable connected to the ultrasonic transducer, a signal such as a clock pulse transmitted to the solid-state imaging device is transmitted from the ultrasonic transducer. There is a possibility of becoming a noise source for the ultrasonic reception signal. From the above, noise countermeasures are generally taken by electromagnetically shielding the cable connected to the ultrasonic transducer.
[0005]
[Problems to be solved by the invention]
By the way, when a shielded cable as described above is used as a cable for transmitting ultrasonic reception signals, disturbance noise can be prevented from being captured. However, even if a shielded cable is used, the generation of noise cannot be completely prevented. In particular, compared to mechanical linear scanning performed by linearly moving the ultrasonic transducer, there is a tendency that noise is generated more frequently when performing mechanical radial scanning that rotationally drives the ultrasonic transducer. .
[0006]
In view of the above points, the present inventor completed the present invention by knowing that electrostatic noise is generated due to static electricity when the ultrasonic vibrator is rotationally driven as a result of earnest research. It came to. In other words, in order to rotationally drive the ultrasonic vibrator by remote control, the ultrasonic vibrator is connected to the tip of the flexible shaft, and this flexible shaft is generally formed by winding a metal wire in a close coil shape. The cable is inserted inside, but the cable is inserted with a certain length of the flexible shaft in order to prevent disconnection due to excessive pulling force. It is common. When the flexible shaft is rotated, the cable naturally follows the rotation, but slides with the flexible shaft as much as the cable has an extra length.
[0007]
The outermost layer portion of the cable is an insulation coating, and static electricity generated when the insulation of the cable, which is an insulator, slides on a flexible shaft made of metal becomes a noise source for the cable. That is, although the insulation coating slides on the flexible shaft, it is discharged at the moment when there is static electricity that is stagnant, but there is a possibility that electrostatic noise generated at the time of discharging the static electricity is taken in at the time of signal transmission. The cable is composed of at least a core wire and a shield wire, and the insulation layer is interposed between the core wire and the shield wire by inserting the core wire through an insulating tube, etc. Sometimes, when the cable slides with the flexible shaft, a force in the direction of twisting the cable itself acts, resulting in relative sliding between the shield wire and the insulating layer. Accordingly, static electricity is also generated by the relative sliding between the shield wire and the insulating layer. However, conventionally, no countermeasure has been taken against static electricity caused by relative sliding between the shield wire and the insulating layer.
[0008]
The present invention has been made in view of the above points, and an object of the present invention is to prevent static electricity from stagnating in a cable connected to an ultrasonic vibrator and to prevent noise caused by this static electricity. There is in doing so.
[0009]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides a sleeve in which a flexible shaft in which a metal wire is wound in a close coil shape is inserted into a sleeve, and an ultrasonic vibrator is connected to the tip of the flexible shaft. An ultrasonic probe that performs mechanical radial scanning by rotating the ultrasonic transducer by rotating the flexible shaft around the axis, wherein the ultrasonic transducer is inserted into the flexible shaft. The cable is inserted into a cable, and a conductive film having a ground potential is formed on the outer peripheral surface of the insulating coating constituting at least the outermost layer of the cable.
[0010]
The cable is composed of one or a plurality of core wires, one or a plurality of shield wires, and an insulating layer interposed between the core wires and the shield wires, but in addition to the insulation coating that is the outermost layer of the cable. Further, it is desirable to provide a conductive film having a ground potential on the outer peripheral surface of the insulating layer from the viewpoint of preventing the generation of static electricity and improving the shielding function. Here, the conductive film can be formed by means such as winding a metal foil or coating the surface. For example, by applying carbon coating, a thin conductive film can be easily formed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described. Here, as an example of a system for performing an ultrasonic examination by being inserted into a body cavity, there is one shown in FIG. In the figure, 1 is an ultrasonic probe, 2 is an ultrasonic operation unit, and 3 is a cord that is detachably connected to an ultrasonic observation apparatus (not shown). For example, the ultrasonic probe 1 is inserted into a treatment instrument insertion channel 6 provided in the insertion part 5 of the endoscope 4, and the ultrasonic operation unit 2 is provided in the main body operation part 7 of the endoscope 4. It is fixed to the treatment instrument introduction part 8.
[0012]
The ultrasonic probe 1 and the ultrasonic operation unit 2 have the configuration shown in FIG. The ultrasonic probe 1 is provided by connecting a distal end cap 11 to the distal end of a flexible sleeve 10, and an ultrasonic transducer 13 mounted on a rotating substrate 12 is disposed in the distal end cap 11. A flexible shaft 14 is connected to the rotary substrate 12, and the flexible shaft 14 has a length that covers the entire length of the sleeve 10. The base end portion of the flexible shaft 14 is connected to the connection connector 15, and the connection connector 15 protrudes from the base end portion of the sleeve 10 by a predetermined length.
[0013]
The ultrasonic operation unit 2 includes an attachment portion 16 that is detachably attached to the treatment instrument introduction portion 8, and a casing 17 that is connected to the attachment portion 16, and the casing 17 includes the ultrasonic probe 1. A rotating shaft 18 is provided to which the connecting connector 15 is detachably connected. A pair of pulleys 19 and 20 are mounted on the rotary shaft 18, and a motor 22 is connected to one pulley 19 via a transmission belt 21, and an encoder is connected to the other pulley 20 via a transmission belt 23. 24 is connected. Therefore, when the motor 22 is rotated, the rotating shaft 18 is rotated, and this rotation is transmitted to the connection connector 15, and the flexible shaft 14 rotates around the axis in the sleeve 10, and as a result, the ultrasonic wave mounted on the rotating substrate 12. Each time the vibrator 13 is driven to rotate and rotates by a predetermined angle, ultrasonic waves are transmitted from the ultrasonic vibrator 13 and reflected echoes from the body tissue are received. This is mechanical radial scanning.
[0014]
Accordingly, a drive signal is input to the ultrasonic transducer 13 at every predetermined angle detected by the encoder 24, and an ultrasonic pulse is transmitted. In addition, a reflected echo from a tomographic part of the body tissue is taken into the ultrasonic transducer 13, and this received signal is transmitted to the ultrasonic observation apparatus. For this purpose, a cable 25 is connected to the ultrasonic transducer 13, and the cable 25 is inserted into the flexible shaft 14. The base end portion of the cable 25 is detachably connected to the rotary shaft 18 via the connection connector 15. Therefore, the rotating shaft 18 functions as a rotation transmission means and also functions as a signal transmission path. The rotary shaft 18 is connected to a rotary connector 26, and a cable 27 drawn from the cord 3 is connected to the rotary connector 26. Accordingly, the cable 27 on the cord 3 side is fixed in the rotational direction, is connected to the ultrasonic transducer 13, and is connected to the cable 25 that rotates together with the ultrasonic transducer 13 and the rotary connector 26 so as to be relatively rotatable.
[0015]
The ultrasonic probe 1 is inserted into the treatment instrument insertion channel 6 of the endoscope 4. The treatment instrument insertion channel 6 is provided in the insertion portion 5 that is inserted into a curved path in the body cavity. In a state where the sonic probe 1 is guided into the body cavity, it bends in an arbitrary direction following the treatment instrument insertion channel 6. The flexible shaft 14 is inserted into the sleeve 10 and the cable 25 is inserted into the flexible shaft 14. The flexible shaft 14 is inserted between the inner diameter of the sleeve 10 and the outer diameter of the flexible shaft 14, and between the inner diameter of the flexible shaft 14 and the outer side of the cable 25. A predetermined difference in diameter is provided between each diameter. The total length of the ultrasonic probe 1 is longer than that of the treatment instrument insertion channel 6, and usually has a length of 2 m or more.
[0016]
From the above, by giving the flexible shaft 14 a predetermined extra length in the sleeve 10, the flexible shaft 14 is smoothly rotated, and a certain extra length is provided in the flexible shaft 14 and the cable 25. Therefore, when the ultrasonic probe 1 is operated in a bent state, the cable 25 is not broken due to tension applied to the cable 25. Since the flexible shaft 14 rotates around the axis in the sleeve 10, the flexible shaft 14 vibrates and contacts with the inner surface of the sleeve 10 during the rotation, so that the flexible shaft 14 vibrates and has an extra length inside. The cable 25 that is inserted in this state slides with each other.
[0017]
FIG. 3 shows the configuration of the cable 25 inserted through the flexible shaft 14. The cable 25 has a core wire 30 disposed at the center thereof, and the periphery of the core wire 30 is covered with an insulating layer 31. A shield wire 32 is attached to the outer peripheral portion of the insulating layer 31 by knitting in a mesh shape, and the shield wire 32 is further covered with an insulating coating 33. This is the basic configuration of the cable 25. When the core wire 30 and the shield wire 32 are connected to both electrodes of the ultrasonic transducer 13 made of piezoelectric elements, and a predetermined voltage is applied between these electrodes, the ultrasonic wave When transmission is performed and the ultrasonic vibrator 13 is vibrated by the reflected echo, a voltage is generated in the ultrasonic vibrator 13, and this voltage signal is taken out from the core wire 30.
[0018]
Here, conductive films 34 and 35 made of carbon coating or the like are formed on the outer surface of the insulating layer 31 and the outer surface of the insulating coating 33, respectively. Both the conductive films 34 and 35 are set to the ground potential. These conductive films 34 and 35 can be formed by means such as dipping, for example, and therefore are easily formed as extremely thin films, and the cable 25 as a whole does not have a particularly large diameter.
[0019]
Thus, a shield wire 32 formed by knitting or the like that is independent of the insulating layer 31 is provided on the outer periphery of the insulating layer 31, and the shield wire 32 is formed of metal. Accordingly, the conductive film 34 is held so that the shield wire 32 does not directly contact the insulating layer 31 made of an electrical insulator. In addition, since the insulating coating 33 is inserted into the flexible shaft 14 in which the metal wire is wound in a close-contact coil shape, in order to prevent the insulating coating 33 from coming into direct contact with the flexible shaft 14 made of metal, A conductive film 35 is laminated on the outer periphery of the insulating coating 33.
[0020]
In order to perform mechanical radial scanning, when the ultrasonic transducer 13 is rotationally driven, the flexible shaft 14 is rotated around the axis. At this time, the entire ultrasonic probe 1 vibrates. As a result, sliding occurs between the outer peripheral surface of the cable 25 and the inner surface of the flexible shaft 14. However, since the conductive film 35 is formed on the surface of the cable 25, the sliding is between the conductors, and the conductive film 35 is held at the ground potential. Therefore, there is no possibility that static electricity is stagnated in any of the sliding members. In addition, the insulating layer 31 and the shield wire 32 are not in a fixed relationship, but are substantially formed by attaching the shield wire 32 to the insulating layer 31. A relative movement occurs between the insulating layer 31 and the shield wire 32, and they slide on each other. However, since the conductive film 34 is also formed on the outer surface of the insulating layer 31 and this conductive film 34 is also grounded, it is possible to reliably prevent the generation of static electricity due to the shield wire 32 being in direct contact with the insulating layer 31.
[0021]
In addition, a conductive film 34 is formed on the outer surface of the insulating layer 31 and a conductive film 35 is formed on the outer surface of the insulating coating 33. Even if twisting or the like occurs, there is no relative sliding and static electricity is not generated. From the above, since the core wire 30 is covered with the conductive films 34 and 35 in addition to the shield wire 32, it is possible to more reliably prevent disturbance noise from being captured.
[0022]
As a result, the cable 25 inserted into the flexible shaft 14 only forms the two thin film conductive films 34 and 35, that is, the cable 25 does not substantially increase in diameter and passes through the cable 25. Thus, it is possible to almost completely prevent noise from being generated in the ultrasonic reflected signal, which is a weak signal transmitted in this manner. Therefore, the S / N ratio is improved when the ultrasonic image signal is generated based on the reflected echo signal, and when this ultrasonic image is displayed on the monitor, the image becomes extremely clear and accurate examination and diagnosis can be performed. Can be done.
[0023]
Here, as the cable connected to the ultrasonic transducer 13, various configurations such as the cable 40 shown in FIG. 4 and the cable 50 shown in FIG. 5 are used in addition to the configuration shown in FIG. . The cable 40 shown in FIG. 4 has core wires 41a and 41b connected to two electrodes of the ultrasonic vibrator 13, and both the core wires 41a and 41b are inserted into the insulating layers 42a and 42b. Is further inserted into the second insulating layer 43, and a shield wire 44 is provided on the outer periphery of the second insulating layer 43. A conductive film 45 is formed on the outer periphery of the second insulating layer 43. Further, an insulating coating 46 is provided on the outer periphery of the shield wire 44, and a conductive film 47 is also laminated on the outer surface of the insulating coating 46. This configuration is used when an ultrasonic transducer having a large surface area is used. That is, the core wires 41a and 41b are connected to both electrodes of the ultrasonic transducer 13, thereby increasing the potential difference generated between both electrodes. Therefore, in this configuration, the shield wire 44 exhibits an electromagnetic shielding function.
[0024]
Further, the cable 50 shown in FIG. 5 is a shield-reinforced cable, and is particularly effective when used in an environment where large noise occurs. That is, the first insulating layer 52, the first shield wire 53, the second insulating layer 54, the second shield wire 55, and the insulating coating 56 are sequentially laminated on the outer side of the core wire 51 provided on the most central side. The conductive film is formed between the first insulating layer 52 and the first shield line 53, between the second insulating layer 54 and the second shield line 55, and outside the insulating coating 56. 57, 58, 59 are formed. In this case, the core wire 51 and the first shield wire 53 are connected to both electrodes of the ultrasonic transducer 13, respectively. The second shield wire 55 is for exhibiting an electromagnetic shield function. Note that the conductive film 57 may be omitted because there is almost no possibility of sliding between the first insulating layer 52 and the first shield line 53.
[0025]
【The invention's effect】
In the present invention, since the conductive film having the ground potential is formed on the outer peripheral surface of the insulation coating at least on the outer peripheral side of the cable, the electromagnetic wave of the cable connected to the ultrasonic vibrator is not increased in diameter. In addition to improving the shielding function, it is possible to prevent static electricity from stagnating in the cable itself, thereby significantly reducing the noise of the ultrasonic echo signal that is a weak signal transmitted through the cable. There is an effect that the ultrasonic image obtained by processing the sound wave reflection signal can be made extremely clear.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an ultrasonic inspection apparatus provided with an ultrasonic probe according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of an ultrasonic probe and its ultrasonic operation unit.
FIG. 3 is an explanatory diagram of a configuration of a cable for an ultrasonic probe showing the first embodiment;
FIG. 4 is a configuration explanatory diagram of a cable for an ultrasonic probe showing a second embodiment.
FIG. 5 is an explanatory diagram of a configuration of an ultrasonic probe cable according to a third embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Ultrasonic operating unit 10 Sleeve 11 Tip cap 13 Ultrasonic vibrator 14 Flexible shaft 25, 40, 50 Cable 30, 41a, 41b, 51 Core wire 31, 42a, 42b, 43, 52, 54 Insulating layer 32 , 44, 53, 55 Shield wire 33, 46, 56 Insulation coating 34, 35, 45, 47, 57-59 Conductive film

Claims (3)

By inserting a flexible shaft in which a metal wire is wound into a close coil into the sleeve, and connecting an ultrasonic vibrator to the tip of the flexible shaft, and rotating the flexible shaft around the axis in the sleeve In the ultrasonic probe adapted to perform mechanical radial scanning by rotationally driving the ultrasonic transducer,
A cable connected to the ultrasonic vibrator is inserted into the flexible shaft, and a conductive film having a ground potential is formed on the outer peripheral surface of the insulating coating constituting at least the outermost layer of the cable. Ultrasonic probe.   The cable is composed of one or more core wires, one or more shield wires, and an insulating layer interposed between the core wires and the shield wire. The ultrasonic probe according to claim 1, wherein a film is provided.   The ultrasonic probe according to claim 1, wherein the conductive film is made of a carbon coating.

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