JPS6054830A - Manufacture of optical sensor - Google Patents

Abstract

PURPOSE:To obtain a capillary optical sensor for use in endoscope and the like by a method wherein light guide material for illumination and cladding material are co-extruded. CONSTITUTION:An image fiber 4 with an optical shielding layer thereon and two metal wires 20 and 20 are supplied from the back of a co-extruder die 15 and core member A, which turns to be light guides for illumination, and cladding member B, the refractive index of which is lower than that of the core member A, are also simultaneously supplied to the co-extruder die 15. After that, the core member A is extruded around the image fiber 4 and the metal wires 20 and 20 into the cylindrical form in the co-extruder die 15. Further, the cladding member B is co-extruded around the just-above mentioned extruded core member A so as to cover the member A in order to get optical sensor preform. Next, said optical sensor preform is cut in lengths and the wires 20 and 20 are so stretched that the diameter of the wires are reduced enough in order to be pulled out of the optical sensor preform. In addition, through-holes 21 for metal wire, flow channels 22 and 25 for cladding member, a flow channel 23 for core member and a light guide formation space 24 are represented in the attached figure.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Technical Field The present invention relates to a method of manufacturing an optical sensor used in an endoscope or the like.

Here, the optical sensor is an image fiber,
A light and image transmission path that includes a light guide for illumination and, if necessary, tubes and holes through which fluid can pass.

Optical sensors are used as light transmission parts of endoscopes for observing the abdominal cavity, heart, and blood vessels. A cylindrical imaging adapter is attached to the tip of the optical sensor. Most imaging adapters and optical sensors are introduced into the human body. The imaging adapter has a lens that forms an image of the interior of the organ onto the front end of the image fiber.

On the proximal side of the optical sensor, a device that constitutes an endoscope (111) is installed. There is an image receiving section that observes the image transmitted through the image fiber. In some cases, it may be displayed as an image on a television monitor.

A light source is provided at the starting end of the illumination light guide.

The light from the light source travels through the light guide path and illuminates the target surface of the internal organs of the human body.

An endoscope only equipped with an illumination light guide path and an image fiber may also be used depending on the object.

Sometimes this is not enough. For example, when observing the inside of the heart, blood obstructs the field of view and must be removed.

Some models introduce physiological saline through a saline inlet and inject it into the heart, instantly removing blood and opening the field of vision. This is undesirable because it introduces saline into the heart.

Therefore, a method was devised in which a transparent balloon was attached to the imaging section. A transparent balloon is filled with saline and inflated to remove blood and reveal the inner walls of the heart.

At first, only one wood fluid passage hole is formed! 7 was used, but with this, when physiological saline was introduced into the transparent balloon, the air inside the transparent balloon could not be expelled.

Therefore, two fluid passage holes were provided, and physiological saline was fed into the transparent balloon through one hole, and the air inside the balloon was evacuated through the other hole.

(B) Prior Art Sensor optical fibers having an image fiber and an illumination light guide are widely used in endoscopes; Many are simply bundled together and have a plastic outer covering.

These optical fibers are manufactured by separately manufacturing the plastic duplex that makes up the outer sheath, the image fiber, and the light guide fiber, and then inserting the image fiber and the light guide fiber into the outer sheath tube from one end. .

As mentioned in the previous section, there is a demand for a composite fiber carrier having an image fiber, an illumination light guide path, and two through holes, but this has also conventionally been produced by an insertion method. A composite fiber was created by inserting an image fiber, an optical fiber for a light guide path, and two duplexes for fluid into a tube forming an outer covering from one end.

Such fibers inevitably have wasteful voids, resulting in poor volumetric efficiency. There is a drawback. When used as an imaging catheter, it is important to have a small overall diameter and a strong illumination light.

In conventional methods, even if a plurality of optical path fibers for illumination were inserted, the total cross-sectional area of the light guide path could not be made very large, resulting in insufficient illumination light.

It would be possible to intensify the illumination light by using a thick optical fiber for the light guide path, but then the overall diameter would become too large to be used in an image catheter for the human body. The condition imposed on the image catheter is that the diameter is 2.3 mm or less.

So did the applicant insert this kind of information? Developed a completely different manufacturing method for optical sensors (Patent application 1986-134)
No. 055).

This does not use a circular cross-section fiber as a light guide. An image fiber and a fluid passage hole are integrally formed in a transparent body with a circular cross section.

The transparent body is used as a light guide path for illumination.

Therefore, the cross section of the illumination light guide has a shape obtained by removing two small circles from a circle.

To manufacture an optical fiber for a sensor, a circular portion forming a fluid passage hole is extruded, using a die having [1], and feeding the image fiber from the rear of this die toward []r1. A transparent plastic material to be used as a conductive C path is simultaneously supplied to the die and coextruded. If necessary, a cladding layer may be provided around the image fiber.

In this way, a transparent optical sensor having an image fiber and one fluid passage hole can be manufactured. The outer diameter can also be made 2-3 mmφ. The portion other than the image fiber and through hole serves as a light guide path for illumination. Even if the outer diameter is small, the effective cross section of the light guide can be widened.

We were able to manufacture an excellent optical sensor equipped with an image fiber, one fluid passage hole, and a light guide path for illumination.

This fluid passage hole is used as an introduction path for physiological saline.

As explained in the previous section, initially (4), physiological saline was directly sprayed onto the observation target area within the heart to remove opaque fluids such as blood. -However, this was harmful to the human body, so It is being replaced by the transparent balloon method.The endoscope with a transparent balloon attached to the tip was also used as a food at first.''
It was thought that it would be sufficient to introduce 1M water into the balloon. However, it was reconsidered that an additional fluid hole was needed to remove residual air from the balloon.

By the manufacturing method described above, one image core, an f-pa,
An attempt was made to create a transparent plastic optical sensor with two fluid passage holes. Since the number of fluid passage holes is only increased by one, it seems that the manufacturing method described above can be used, but this was not the case.

The condition that the outer diameter is 2.3 mmφ or less remains the same, but since two through holes are made, the cross-sectional area of each through hole must be narrower. It was not possible to make it by devising the circular part of one of the sticks. The through hole of the extruded optical sensor begins to close.

The overall diameter is 2.3 mm, there is an image fiber inside, and there are two fluid passage holes, so the diameter of the through holes is 0.7 mm or less. It is difficult to form such a thin through hole throughout the entire area without opening it.

Cross-sectional views of an optical sensor to be manufactured according to the present invention are shown in FIGS. 1 and 2.

1.5.8 is a cladding layer, and 2 is a 1-to-1 light rod optical path. The cladding layer 1.5.8 is made of plastic having a lower refractive index than the core (light guide path 2 for illumination), and has the effect of confining the illumination light within the core.

A light shielding layer 3 is coated around the image fiber 4 to prevent light from entering the image fiber. There are two fluid holes 6.7, one for saline inlet and one for air out.

In the case shown in FIG. 2, the cladding layer is provided only on the entire outer periphery (cladding layer 1).

In the one shown in FIG. 1, the cladding layer 5.8 further includes two
They are also provided around the two fluid passage holes 6.7, the image fiber 4, and the light shielding layer 3.

(ri) Manufacturing method of the present invention FIG. 3 is a configuration diagram of an optical sensor preform manufacturing apparatus for explaining the optical sensor manufacturing method of the present invention.

9.11 is a metal wire supply, and 10 is an image fiber ply, each of which continuously feeds a metal wire and an image fiber to the extruder head.

Reference numeral 12 denotes a guide roller for guiding the metal wires, and appropriately defines the interval between the metal wires.

13 is a light guide path material extruder for illumination.

14 is a cladding material extruder.

The two through holes in the illumination light guide are for forming the saline inlet 6 and the air outflow lower. After the sensor preform is ready, it is pulled out and removed.After removal, a through hole 6.7 remains.

If necessary, the surface of the metal foil 20 is coated with a release agent such as Teflon or silicone to facilitate pulling out.

A coextrusion die 15 is provided between the illumination light guide material extruder 13 and the clad 4A/I extruder 14.

The coextrusion die 15 receives the illumination light guide paulownia from the illumination light guide material extruder 13 , and receives the clad paulownia material from the clad milling extruder 14 .

The coextrusion die 15 is an extruder spatula r where two extruders are combined.
The image fiber 4 and the metal wires 20 and 20 pass through from the rear in the direction 111j.

In the co-extrusion die 15, the illumination light guide material and the Q cladding material are guided to appropriate positions and extruded together 411.

The internal structure of the coextrusion die 159 differs depending on whether the X-dimensional sensor shown in FIG. 12 is manufactured or the optical sensor shown in FIG. 2 is manufactured.

When manufacturing the optical sensor shown in FIG. 2, the metal wire 20 and the image fiber 4 having the light shielding layer 3 are supplied from the rear of the coextrusion die 15 in a continuous manner. Directly to the outside of the image fiber 4,
We supply light guide materials for lighting. Due to the internal structure of the die 15, the illumination light guide material is shaped to have a circular cross section.

After the illumination light guide is formed in the coextrusion die 15, a cladding strip is fed to the second outer circumference of the illumination light guide.

After the diameter of the cladding layer 1 is sized, a metal wire 20 and an image fiber 4 are inserted from the exit of the coextrusion die 15.
An illumination light guide path 2 that includes a cladding layer 1 on the outer periphery.
are extruded as one.

This can be called an optical sensor preform 17.

Optical sensor preform 17 is cooled as it passes through cooling zone 16 . ■Open light guide path 2 and cladding layer 1
The plastic paulownia 1 that should be made of solidifies.

In front of the cooling zone 16 is a take-up re-cabinet 1B which takes the optical sensor preform 17 forward.

Further forward of the take-up capstan 18 is a winder 19.
Then, the optical sensor preform 17 is sequentially wound up.

The above is Step 1 of "Production of optical sensor preform 11".

As already mentioned, the internal structure of the coextrusion die 15 (T'η structure) differs depending on whether the optical sensor shown in FIG. 1 or FIG. 2 is manufactured.

When manufacturing the optical sensor shown in FIG. 1, a cladding layer 8.5.5 must also be formed on the light shielding layer 3 of the image fiber 4 and on the outer periphery of the metal wire 20.

FIG. 4 is a sectional view showing the internal structure of a coextrusion die to be used for such applications.

The co-extrusion die 15 has, from the rear, a metal wire through hole 21 through which the metal wire 20 should pass, and an image 7 eyeper 4.
There is an image fiber through hole (not visible in the diagram) that the image fiber should pass through.

The metal wire through hole 21 and the image fiber through hole are the cladding material flow path 2 into which the cladding material first flows.
Intersect with 2. Here, a thin layer of cladding material adheres to the outer periphery of the metal gloss 20 and the image fiber 4.

Metal wire 20 coated with cladding material B, image 7
The eyeper 4 enters a cylindrical light guide path forming space 24 that follows the core material flow path 23 . Here, the core material A spreads into a cylindrical space and adheres to the outer periphery of the image fiber 4 and the metal wire 20.

When the filling of the core material A is completed, the cladding U B is supplied to the outer circumferential surface of the core material A through the cladding material channel 25 provided further forward. Clad material B has a thin layer on the surface of the core material.
It is coated in a single kanji shape.

In this way, the cladding material is formed by forming the cladding layer 8.2 on the outer periphery of the image fiber 4, the cladding layer 5 on the outer periphery of the wooden through hole 6.1, and the cladding layer 1 on the outer periphery of the illumination 2 and optical path 2. Form.

The core N'A and the cladding material B pass through a coextrusion die 15 and are cooled and solidified while passing through a cooling zone 16. This is sequentially wound up by a winding machine 19.

FIG. 6 shows a cross section of the optical sensor preform.

The optical sensor preform 11 is still composed of metal wires 20.
20 is inserted into the part that should become the through hole 6.1. To remove the metal gloss 20.2o, proceed as follows.

FIG. 4 shows a metal wire drawing device.

Optical sensor preform 1γ, suitable length, e.g. 3
Cut every m. Furthermore, both ends are slightly cut to expose the metal wires 2o, 20'.

The optical sensor preform 17 is placed longitudinally on the base 31 of the metal wire drawing device 3o. The metal wire 20.20 exposed from one end is held between the presser plates of the fixed wire presser 32 at the end of the base 31, and fixed by tightening the setscrew 37.

The metal wire 20.20 exposed from the other end is held between the presser plates of the moving wire presser 33 and fixed by tightening the setscrew 38.

The moving wire presser 33 has screw threads 34 parallel to the longitudinal direction.
is installed. A handle 3 is attached to the other end of the screw thread 34.
5 is fixed, and the intermediate part is attached to the base 3 by a screw top 36.
Take it to 1 (=J get kicked off.

When the handle 35 is turned, the threaded rod 34 rotates; the moving wire presser 33 moves left and right.

Then, by turning the handle 35 and strongly pulling the moving wire presser 33, the metal wire 20.20 is stretched. When a metal wire is stretched beyond its elastic limit, the wire deforms plastically and becomes thinner.

A gate is created between the metal wire and the through hole 6.7. Furthermore, because the wire and the wall surface of the through hole 6.7 are displaced due to the stretching operation, the same adhesion force between the two is almost eliminated.

Optical sensor preform 17 from metal twirling device 30
The metal wire 20.20 is removed from the optical sensor preform 17 using a suitable device.

In this way, an optical sensor whose cross-sectional views are shown in FIGS. 1 and 2 is produced.

In conclusion, the method for manufacturing an optical sensor of the present invention includes (1) supplying the image fiber 4 having the light shielding layer 3 and the two metal wires 20, 20 from the rear of the coextrusion die 15, and (2) supplying the optical sensor for illumination. The core U'A, which is to become the light guide path 2, and the cladding material B, which has a lower refractive index than the core material 'A, are co-extruded through a die 1.
(3) In the co-extrusion die 15, core material A is extruded into a cylindrical shape around the image fiber 4 and metal thread 20.20, (4) Furthermore, a cladding material is supplied around one core material A. extruding the optical sensor preform 17 by coating B; (6) cutting the optical sensor preform 11;
The process consists of the steps of stretching the metal thread 20, 20 to reduce its diameter, and pulling it out from the optical sensor pre-au molded body 1γ.

(1) Effect +1) It becomes possible to manufacture an optical sensor with an outer diameter as small as 2 NM. The effective cross-sectional area of the light guide can be increased.

This is because the illumination light guide material and the cladding material, which has a lower refractive index than the light guide material, are extruded by co-extrusion to form a sensor.

(2) The inner diameter and positional relationship of the two through holes, saline inlet and air outlet, are accurate.

A metal wire is supplied to form two through holes, and the outer diameter of the wire becomes the inner diameter of the through holes. The positional relationship of the through holes is the wire supply and is accurate.

(3) Good light transmission characteristics of the illumination light guide path. Since the cladding layer is provided on the core material by co-extrusion, the light guide path (core)
Avoid getting scratches or dirt on the surface.

(4) Excellent mass productivity.

Since it is manufactured using an extrusion method, long products can be produced continuously.

(E) Applications The optical sensor manufactured according to the present invention can be used in various small diameter image fiber catheters.

(force) example An example will be described.

The image fiber 4 has 3000 pixels, the diameter of the pixel portion is 0.5 φ, and the outer diameter including the light shielding layer (also referred to as a light absorption layer) 3 is 0.9 FIIm.

As the metal wire 20, an annealed copper wire with a diameter of 0.6 mm was used.

The material of the light guide path (core) for illumination is (il PMiVIA (polymethyl methacrylate)
(11) Adipate ester plasticized PMMAfiii
A copolymer of n-butyl meccrylate, imptyl noccrylate, etc. can be used.

The cladding material corresponds to the core material mentioned above, and for the core material (1), vinylidene fluoride and tetrafluoroethylene copolymer are used, and for (11) and ■), methacrylic acid and fluorine-containing are used. Polymers, copolymers, etc. of alkyl esters are used.

The extrusion temperature varies depending on the combination of core and cladding, but it is 240°C when the core is (1), and 200°C to 150°C when the core is (II) (open).

The take-up speed is 5 to 1Q772/min.

The thickness of the cladding layer was set to o-o4.

The outer diameter of the entire optical sensor was 2.3 armφ.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an optical sensor to be manufactured by the method of the invention. A cladding layer is provided around the image fiber, the saline inlet, the air outlet, and the outer periphery of the light guide. FIG. 2 is a sectional view of an optical sensor to be manufactured by the method of the invention. A cladding layer is provided only around the outer periphery of the light guide. FIG. 3 is a block diagram of an apparatus for manufacturing an optical sensor preform. FIG. 4 is a perspective view of a state in which a metal wire in a preform is being stretched by a metal wire stretching device. Fig. 5 is a sectional view of the extrusion die. Fig. 6 is a sectional view of the optical sensor preform. 1... - Clad layer 2 - Light guide path for illumination (core) 3 - ... Light shielding layer 4 ... - Image fiber 5 ... ... Cladding layer 6 ... ... Physiological saline inlet A - Air inlet 8 ... Cladding layer 9.11 - ...・・Metal wire thebly 10・・・・−
Image fiber thebly 12...-Guide roller 13...Illumination light guide path material extruder 14.
・・・・・・・・・Clad material extruder 15・・・・・・
Coextrusion die 16 Cooling zone 17 Optical preform 18
・・・・・・・・・Collection capstan 19・・・・
...... Winder 20 ... - ... Metal twister 21 ... -.
・・・・・・Metal wire through hole 22・・・・・・・・・・・・
- Cladding material flow path 23... Core material flow path 24... Light guide path forming space 25 -
・・・・・・Clad material flow path A・・・・・・・・・
・Core material - B・・・・・・－・－・・・Clad material Inventor Taketsune Moriyo Matsumiya Kibunjo Yoshinobu Ha Patent applicant Sumitomo Electric Industries, Ltd. Figure 1 Figure 2

Claims (3)

[Claims] (1) Image fibers 4 and 2 with light speed 1 layer 3
A wooden metal wire 20.20 is supplied from the rear of the coextrusion die 15, and the core material A, which is to become the illumination light guide path 2, and the cladding material B, which has a lower refractive index than the core material A, are simultaneously fed into the coextrusion die 15. The core material A is then extruded into a cylindrical shape around the image fiber 4 and the metal wire 20, 20 in the co-extrusion die 15, and the core material A is further coated with the clad material B to prepare an optical sensor. An optical sensor characterized in that a molded body 17 is extruded, the optical sensor pre-ab molded body 17 is cut, a metal thread 20, 20 is stretched to have a smaller diameter, and then pulled out from the preformed body 17. Production method. (2) In the coextrusion die 15, the image fiber 4,
The method of manufacturing an optical sensor according to claim 1, wherein the outer periphery of the metal wire 20, 20 is thinly coated with the cladding material B, and then the core material A is extruded into a cylindrical shape. (3) The method for manufacturing an optical sensor according to claim (1), wherein the surface of the metal wire 20, 20 is coated with a release agent such as Teflon or silicone in advance.