JP3218010B2 - Tactile sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tactile sensor which is mounted on a distal end of a long tube such as a medical catheter tube or a laparoscope used for a human body.

[0002]

2. Description of the Related Art When a medical catheter tube, a laparoscope, etc. are inserted into a living body, it is necessary to prevent the inner wall of the blood vessel, the organs, and the like from being strongly pushed and damaged. Therefore, research and development of a tactile sensor that is attached to the distal end portion of a medical catheter tube, a laparoscope, or the like and detects a pressure applied thereto has been conventionally performed.
Examples of such a tactile sensor include a mechanical switch method, a pressure resistance conversion method, a pressure-voltage conversion method, and a pressure light conversion method.

The mechanical switch system converts a pressure into a mechanical ON / OFF operation of the switch by a spring or the like and detects the converted signal as an electric signal, and is the easiest to handle and the most reliable.

[0004] The pressure resistance conversion method is a method of detecting a distortion of an elastic body caused by pressure by converting the distortion into an electric resistance, and a typical example thereof is a strain gauge or a semiconductor pressure sensor. A strain gauge is a force sensor that forms a resistive film such as a copper-nickel alloy on a film and detects displacement of the film as a change in resistance of the resistive film. In addition, a semiconductor pressure sensor forms a diffusion resistance by diffusing impurities into a diaphragm provided on a silicon wafer, and detects displacement of the diaphragm as a resistance change of the diffusion resistance, and is generally used as a fluid pressure sensor. It is often used, but it can also be used as a load sensor by packaging it with silicone rubber or the like. In addition, there is a so-called pressure-sensitive conductive rubber in which conductive fine particles are dispersed in silicon rubber and a displacement when a force is applied to the silicon rubber is detected as a resistance change.

[0005] The pressure-voltage conversion system converts pressure into an electric signal by utilizing a piezoelectric effect. As the piezoelectric effect element, PZT, a polymer material such as polyvinylidene fluoride (PVDF), or a compound thereof is used, and a voltage generated when these are subjected to pressure is detected.

The pressure-light conversion method converts pressure into a change in light intensity or phase, for example, by placing a sponge or rubber on a transparent glass plate, and applying pressure to the sponge or rubber. There is one that detects the reflectance of glass that changes according to the temperature. In addition, there is a so-called light-blocking method in which a shield that is displaced according to pressure is placed between a light emitting diode and a phototransistor to detect the amount of light received by the phototransistor.

Further, as a pressure-light conversion type tactile sensor used for a medical catheter tube, a laparoscope, or the like, a reflection surface provided on a cantilever-shaped member displaced by pressure is irradiated with light from an optical fiber. A device that detects the intensity of the reflected light via the same optical fiber has already been proposed.

[0008]

However, in the mechanical switch system and the pressure resistance conversion system, the tactile sensor becomes large to some extent, so that it is difficult to attach it to the tip of a thin medical catheter tube or a laparoscope. There is. Further, the pressure-voltage conversion method has a problem that since pressure due to pressure can be detected only differentially (change in pressure) due to charge outflow during measurement, steady pressure information cannot be known.

In addition, since all of these systems detect pressure by converting it into an electric signal, the system is susceptible to electromagnetic interference from external equipment and the like, and there is also a problem that highly reliable detection cannot be performed. . In addition, pressure-light conversion tactile sensors that detect changes in the refractive index of glass or light-blocking tactile sensors convert optical signals into electrical signals at the distal end of a medical catheter tube, laparoscope, etc. The conversion also makes it more susceptible to electromagnetic interference. Furthermore, these pressure-light conversion type tactile sensors require a certain size of a glass plate or a detection unit composed of a light-emitting diode and a phototransistor, and are attached to a distal end of a thin medical catheter tube, a laparoscope, or the like. There is also a problem that this is not always easy.

On the other hand, a pressure-light conversion type tactile sensor using an optical fiber is less susceptible to electromagnetic interference and can be downsized to some extent in terms of space. However, since this conventional tactile sensor has a complicated operating part such as a cantilever attached externally to a distal end portion of a medical catheter tube, a laparoscope, or the like, the distal end portion becomes somewhat large and However, there has been a problem that the assembly work is complicated.

The present invention has been made in view of the above circumstances, and is subject to electromagnetic interference only by attaching an optical fiber by attaching a diaphragm support plate having a simple structure to the distal end of a long tubular body. It is an object of the present invention to provide a tactile sensor that is small and easy to assemble.

[0012]

According to a first aspect of the present invention, there is provided a tactile sensor, wherein a slit is formed on a peripheral side surface below a convex portion formed on a peripheral portion of an upper end surface of a long tubular body. The tip of the optical fiber disposed along the longitudinal direction on the peripheral side of the long tube is guided into the slit from below, and bends into the ceiling of the slit due to the deformation of the ceiling. A reflection portion is formed.

According to the first aspect of the present invention, when the convex portion formed on the peripheral edge of the distal end of the long tubular body receives pressure from the front,
This pressure is transmitted to the ceiling of the lower slit, and the ceiling is deformed and the reflecting portion is bent. Then, when light is emitted from the tip of the optical fiber, this light is reflected by the reflecting portion through the slit, and the reflection angle and phase of the reflected light are changed according to the bending. For this reason, if the light reflected by the reflecting portion is incident via the optical fiber and the change in the intensity or phase is measured, the pressure applied to the convex portion can be detected. Therefore, according to the tactile sensor of the present invention, since the pressure is converted into an optical signal, there is no electromagnetic interference, and since only the reflecting portion is provided on the ceiling portion of the slit, the tip portion of the long tubular body is provided. The assembly can be easily performed with almost no change in size.

According to a second aspect of the invention, there is provided a tactile sensor, wherein a slit is formed on a peripheral side surface below a convex portion formed on a peripheral portion of an upper end surface of the long tubular body. The distal end of the optical fiber arranged along the longitudinal direction on the peripheral side of the slit is guided into the slit from below, and the diaphragm block in which the diaphragm of the metal thin film is formed on the upper surface where the through hole is opened is formed by the slit. It is characterized by being inserted into.

According to the second aspect of the present invention, when the convex portion formed on the peripheral edge of the distal end of the long tubular body receives pressure from the front,
This pressure is transmitted to the ceiling of the lower slit. Then
The diaphragm made of a thin metal film on the upper surface of the diaphragm block inserted into the slit bends under the pressure.
Then, when light is emitted from the tip of the optical fiber, the light is reflected on the lower surface of the diaphragm through the through hole of the diaphragm block, and the reflection angle and phase of the reflected light are changed according to the bending. For this reason, if the reflected light from the diaphragm is incident via an optical fiber and the change in the intensity or phase is measured, the pressure applied to the convex portion can be detected. Therefore, according to the tactile sensor of the present invention, since the pressure is converted into an optical signal, there is no electromagnetic interference, and since only a small diaphragm block is inserted into the slit of the long tubular body from the peripheral side surface. In addition, assembling can be easily performed without substantially changing the size of the distal end portion of the long tubular body. Further, in the case of the first aspect of the invention, there is a difficulty in manufacturing when forming the reflection portion on the ceiling portion of the minute slit, but in the case of the present invention, the diaphragm serving as the reflection portion is formed in advance. Since it is only necessary to insert the diaphragm block into the slit, the production becomes easy. In addition, since a space is formed below the diaphragm serving as the reflecting portion by the through-hole of the diaphragm block in the same manner as in the first aspect of the present invention, high-sensitivity measurement using light becomes possible.

According to a third aspect of the present invention, a slit is formed on a peripheral side below a convex portion formed on a peripheral portion of an upper end surface of the long tubular body, and a slit is formed on a peripheral side of the long tubular body. The distal end of the optical fiber disposed along the longitudinal direction of the portion is guided into the slit from below, and a block having a reflective portion on the upper surface or lower surface is inserted into the slit.

According to the third aspect of the present invention, when the convex portion formed on the peripheral edge of the distal end of the long tubular body receives pressure from the front,
This pressure is transmitted to the ceiling of the lower slit. Then
The block inserted into the slit bends under the pressure. Therefore, when light is emitted from the tip of the optical fiber, this light is reflected by the reflecting portion on the lower surface of the block, or is transmitted through the block and reflected by the reflecting portion on the upper surface. The phase changes. For this reason, the reflected light from the reflected light enters through an optical fiber,
By measuring the change in the intensity or the phase, the pressure applied to the projection can be detected. Therefore, according to the tactile sensor of the present invention, since the pressure is converted into an optical signal, there is no electromagnetic interference, and a minute block is simply inserted into the slit of the long tube from the peripheral side. The assembling can be easily performed with almost no change in the size of the distal end portion of the long tubular body. Furthermore, as in the case of the second aspect of the present invention, it is only necessary to insert a block provided with a reflecting portion into the slit, thereby facilitating the production. In addition, in the case of the first aspect of the invention, there is a possibility that the reflecting portion formed on the ceiling portion of the slit may be broken or peeled off. The reflective portion of the metal thin film may be damaged, or the metal thin film may cause fatigue failure due to repeated bending. In the case of the present invention, the upper or lower surface of the block itself becomes the reflective portion, Since the reflecting portion such as a metal thin film is formed on the upper surface or the lower surface, the possibility of damage is reduced and the durability is improved. In the case of the second aspect of the present invention, it is not always easy to align the through hole and the optical fiber when the diaphragm block is inserted into the slit. Is used as a reflecting portion, it is possible to eliminate this difficulty in alignment.

In any of the above inventions, the optical fiber for irradiating the light and the optical fiber for receiving the reflected light may be the same or different. .

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 7 show an embodiment of the present invention. FIG. 1 is an assembled perspective view of a tactile sensor attached to a distal end portion of a medical catheter tube, and FIG. 2 is a perspective view of the medical catheter tube. FIG. 3 is a perspective view of a silicon chip, FIG. 4 is a longitudinal sectional view showing a manufacturing process of the silicon chip, FIG. 5 is a perspective view of a distal end of a medical catheter tube to which a tactile sensor is attached, and FIG. FIG. 7 is a partially enlarged longitudinal sectional view for explaining the operation, and FIG. 7 is a longitudinal sectional view showing another configuration of the silicon chip.

In the present embodiment, a tactile sensor attached to the distal end of a medical catheter tube 1 as shown in FIG. 2 will be described. The medical catheter tube 1 is a long tube in which a plurality of lumens 1a, which are through holes along the longitudinal direction, are formed in a flexible and elongated synthetic resin such as segmented polyurethane, silicone rubber, or polyvinyl chloride having a diameter of about 3 mm. Body. Here, a medical catheter tube 1 in which three lumens 1a are formed is exemplified. In this case, the two lumens 1a are used for projecting the forceps from the opening in the distal end surface so that the forceps can be operated, or for injecting or sucking physiological saline or the like, and the remaining slightly smaller lumen 1a is used for imaging. It is used as a light guide / image guide for emitting illumination light from the distal end through the optical fiber 2 and imaging the return light.

The medical catheter tube 1 is shown in FIG.
As shown in FIG. 5, convex portions 1b protruding forward are formed at equal intervals at three positions on the peripheral edge of the front end surface facing upward. In addition, a slit 1c that opens to the peripheral side surface is formed below each of the projections 1b. The slit 1c has a width, depth and thickness of 450 μm × 45.
A silicon chip 3 having a size of 0 μm × 100 μm is inserted. Further, below these slits 1c, there are formed grooves 1d which are open on the peripheral side surface and are long along the longitudinal direction. A multi-mode sensor optical fiber 4 having a diameter of 125 μm is inserted into these grooves 1d.

The slits 1c and the grooves 1d have a size such that the segmented polyurethane or the like of the medical catheter tube 1 is etched using an excimer laser so that the silicon chip 3 and the sensor optical fiber 4 can be inserted, respectively. Formed. When a short-wavelength excimer laser is irradiated on a polymer film, the chemical bond chains of the polymer are broken and vaporized / evaporated (called laser ablation), and the laser-irradiated portion is removed. Laser etching becomes possible. This laser irradiation system forms an image of a mask irradiated with KrF excimer laser light having a wavelength of 248 nm on a sample surface, and sets a projection magnification to about 1/20. This sample surface can be observed on a monitor through an observation optical system that partially shares the optical system with the laser irradiation system, and these laser irradiation system and the observation system are adjusted so that an image is formed at the same position on the sample. . The mask image is focused by moving the sample in the optical axis direction so that a focused image is obtained on the monitor. Using this laser irradiation system, a beam size of 50 is applied to the polyurethane sample surface which is relatively easily ablated.
Irradiating an excimer laser of μm × 50 μm gives a depth of 5
A penetration process of 00 μm becomes possible.

The silicon chip 3 is, as shown in FIG.
Square silicon crystal plate (450 μm × 450 μm
× 100 μm). First, as shown in FIG. 4, a gold (Au) thin film is formed
A diaphragm 3a having a size of 30 μm × 130 μm is formed, and as shown in FIG. 3, a through hole 3b is formed by performing anisotropic etching from the lower surface of the silicon chip 3. However, in practice, it is manufactured by processing a large number of silicon chips 3 collectively on a silicon wafer and finally separating the elements. Since the detection diaphragm 3a requires a metal thin film that is optically sufficiently flat, it is manufactured using such a semiconductor manufacturing process. Silicon chip 3 manufactured in this manner
Are inserted into each slit 1c at the distal end of the medical catheter tube 1, as shown in FIG.

The sensor optical fiber 4 is arranged along the longitudinal direction on the peripheral side of the medical catheter tube 1 by being inserted into each of the grooves 1d. The tip of the silicon chip 3 is disposed so as to face the through hole 3b of the silicon chip 3 in the slit 1c. These optical fibers for sensor 4 emit light from the base side of the medical catheter tube 1 from the distal end, and send light incident from the distal end to the base side of the medical catheter tube 1. .

According to the tactile sensor configured as described above, as shown in FIG. 6, light emitted from the tip of each sensor optical fiber 4 passes through the through hole 3b of the silicon chip 3 inserted into the slit 1c. The light is reflected straight on the back surface of the diaphragm 3a, directly enters the same sensor optical fiber 4, and is sent to the base of the medical catheter tube 1. At the base of the medical catheter tube 1, these sensor optical fibers 4 are branched by a multi-mode coupler (not shown), and one of them is connected to a light source of emitted light and the other is connected to a light receiving unit. The intensity of the reflected light at 3a can be measured. Here, when pressure is applied from the front to the protrusion 1b on the peripheral edge of the distal end of the medical catheter tube 1, the ceiling of the slit 1c is pushed downward, and the diaphragm 3a of the silicon chip 3 is bent. Then, the reflection angle on the back surface of the diaphragm 3a changes, and the loss when the reflected light is incident again from the tip of the sensor optical fiber 4 increases. Therefore, the decrease in the intensity of the reflected light can be measured on the base side, and the pressure applied to the distal end of the medical catheter tube 1 can be detected. Further, it is possible to detect which of the three convex portions 1b is subjected to pressure.

For this reason, the tactile sensor according to the present embodiment converts the pressure applied to the distal end of the medical catheter tube 1 into an optical signal and sends the optical signal to the base side through the optical fiber 4 for the sensor. Disappears. Also,
Since only the minute silicon chip 3 is inserted into the slit 1c formed at the distal end of the medical catheter tube 1, the tactile sensor can be easily assembled without increasing the distal end. become.

In the above-described embodiment, a gold vapor-deposited film is used for the diaphragm 3a of the silicon chip 3. However, an aluminum or other metal thin film formed by a method such as vapor deposition or sputtering may be used. Further, the silicon chip 3 may be a diaphragm block of any material as long as the diaphragm 3a of the metal thin film can be supported flat.

Further, in the above embodiment, the case where the silicon chip 3 in which the diaphragm 3a is arranged at the upper end opening of the through hole 3b is used, but the silicon chip 3 without the through hole 3b can be used as it is. . In this case, light emitted from the tip of the sensor optical fiber 4 is reflected on the lower surface of the silicon chip 3. Further, for example, when an LED light source having a wavelength of 1.3 μm is used, since this light passes through the silicon chip 3, as shown in FIG. 5, or the silicon chip 3 shown in FIG. 4 can be used as it is, and the diaphragm 3a on the upper surface can be used as a reflecting portion. Also in these cases, a block of another material can be used instead of the silicon chip 3. Further, instead of inserting the silicon chip 3 or the like into the slit 1c of the medical catheter tube 1, it is also possible to form a metal thin film or the like on the ceiling of the slit 1c to form a reflecting portion.

Further, in the above embodiment, the case where the convex portions 1b are provided at three places on the peripheral edge of the distal end of the medical catheter tube 1 has been described, but the present invention is not limited to this number. Further, the shape of the convex portion 1b is not limited to the illustrated one, and may be any shape as long as it protrudes from the distal end surface of the medical catheter tube 1.

Further, in the above embodiment, each slit 1
Although one sensor optical fiber 4 is arranged for each c, two or more sensor optical fibers 4 for irradiation light and reflected light can be arranged. In this case, a multi-mode coupler is unnecessary. Become. In the above embodiment, the reflected light is detected by the intensity modulation method. However, the reflected light can be detected by the phase modulation method. In this case, it is possible to detect the reflection light by using only one single-mode sensor optical fiber 4. Become. However, the detection of the phase modulation method requires a complicated interference optical system measuring device.

Further, in the above embodiment, the tactile sensor used at the distal end of the medical catheter tube 1 has been described. However, the present invention is not limited to this, and the present invention can be applied to a tactile sensor used at the distal end of any flexible long tube. It is possible. Further, the present invention can be similarly applied to a tactile sensor used at the tip of a rigid long tubular body such as a laparoscope.

[0033]

As is clear from the above description, according to the tactile sensor of the present invention, an optical fiber is arranged by providing a convex portion or a slit at the tip of a long tubular body, and reflecting light on the ceiling of the slit. Simply by forming a part or inserting a diaphragm block or a block into this slit, the pressure applied to the distal end of the long tubular body from the front can be detected. At this time, since the pressure is converted into an optical signal,
Eliminates electromagnetic interference. Moreover, there is no need to attach any parts outside the tip of the long tube,
There is no danger that the tip will become large, and assembly can be performed easily.

[Brief description of the drawings]

FIG. 1, showing one embodiment of the present invention, is an assembled perspective view of a tactile sensor attached to a distal end of a medical catheter tube.

FIG. 2, showing an embodiment of the present invention, is a perspective view of a medical catheter tube.

FIG. 3, showing an embodiment of the present invention, is a perspective view of a silicon chip.

FIG. 4 illustrates one embodiment of the present invention, and is a longitudinal sectional view illustrating a manufacturing process of a silicon chip.

FIG. 5, showing one embodiment of the present invention, is a perspective view of a distal end portion of a medical catheter tube to which a tactile sensor is attached.

FIG. 6, showing an embodiment of the present invention, is a partially enlarged longitudinal sectional view for explaining the operation of a tactile sensor.

FIG. 7, showing an embodiment of the present invention, is a longitudinal sectional view illustrating another configuration of a silicon chip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Medical catheter tube 1b Convex part 1c Slit 3 Silicon chip 3a Diaphragm 3b Through hole 4 Optical fiber for sensor 5 Reflecting part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01L 5/00 G01L 9/00 A61B 5/00

Claims (3)

(57) [Claims] 1. A slit is formed in a peripheral side of a long tubular body below a convex portion formed on a peripheral edge of an upper end surface thereof. A tactile sensor characterized in that a tip of an optical fiber disposed along the slit is guided into the slit from below, and a reflecting portion is formed on a ceiling portion of the slit so as to bend as the ceiling deforms. 2. A slit which is opened on a peripheral side surface below a convex portion formed on a peripheral portion of an upper end surface of the long tubular body, and is formed on a peripheral side portion of the long tubular body in a longitudinal direction. The tip of the optical fiber arranged along is guided into the slit from below, and a diaphragm block in which a diaphragm of a metal thin film is formed on the upper surface where the through hole is opened is inserted into the slit. Tactile sensor. 3. A slit opening on a peripheral side surface is formed below a convex portion formed on a peripheral portion of an upper end surface of the elongated tubular body, and a slit is formed on a peripheral side portion of the elongated tubular body in a longitudinal direction. A tactile sensor characterized in that the tip of an optical fiber arranged along is guided into the slit from below, and a block provided with a reflecting portion on an upper surface or a lower surface is inserted into the slit.