JP2925173B2 - Fiberscope - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fiberscope used for a medical endoscope, an industrial endoscope, or the like.

[Prior Art] FIG. 1 shows a conventional fiberscope.

In this fiberscope 1, a main part of a quartz-based image fiber 2 is inserted into a protective tube 3, an end 4 of the image fiber 2 on the objective side is accommodated in an objective body 5, and an end 6 on the eyepiece side is connected to the objective body 5. It is housed in an eyepiece body 7, further mounted with an objective lens 8 in the object body 5, and mounted with an eyepiece 9 in the eyepiece body 7.

As shown in FIG. 2, the image fiber 2 has thousands to tens of thousands of cores 10, 10,..., A common clad 11 covering these cores, and a quartz jacket 12 outside the clad 11. In order to further improve the mechanical strength, the outside of this quartz jacket 12 has a coating resin
13 are coated.

In order to obtain such an image fiber 2, a large number of core / clad fiber strands are assembled, aligned, and packed in a quartz jacket 12. Next, this is heated in a heating furnace, and the cladding of many optical fiber wires is welded and integrated to draw a wire, and the surface thereof is coated with a coating resin 13. The image fiber thus obtained is cut into a predetermined length, and both ends thereof are polished to a mirror surface before use.

In the fiber scope 1, incident light enters through the objective lens 8 from the objective side surface 4 a of the image fiber 2, exits from the eyepiece side end surface 6 a, and obtains an image through the eyepiece 9. ing.

However, since the image fiber 2 has a structure having a large number of cores in the clad 11 welded and integrated as described above, incident light cannot be incident only on the core, and the Light enters and propagates. In addition, light propagating in the core 10 leaks into the cladding 11, and light propagating in the cladding 11 enters another adjacent core 10.

Therefore, the light propagating in the cladding 11 causes
This leads to deterioration of image quality such as blurring of an image taken out from the end face 6a on the eyepiece side of the image fiber 2.

As one method of preventing the image quality deterioration, in order to remove the light propagating in the cladding 11, as shown in FIG. There is a method of providing.

As shown in FIG. 3, the deformed portion 20 is formed by removing a part of the coating resin 13 of the image fiber 2 and further bending the deformed portion 23 into the stainless steel pipe 21. Further, the image fibers 2, 2 communicating with the outside of the stainless steel pipe 21 pass through holes 24a, 24a provided in the lids 24, 24 of the stainless steel pipe 21, and are connected to the ends 23a, 23a of the deformed portion 23. Connected. The interior of the stainless steel pipe 21 is filled and fixed with an epoxy resin 22.

 This deformed part 20 is created as follows.

First, as shown in FIG. 4, a part of the image fiber 2 is heated with an oxygen-hydrogen flame burner 25 to burn and remove the coating resin 13 on the surface, and the exposed glass part is softened. Then, the softened portion is subjected to bending or torsion plastic deformation.

Since the coating resin 13 is burned off by the heating in the deformed portion 23 where the image fiber 2 is subjected to the plastic deformation such as bending or torsion, the epoxy resin 22 is added to the deformed portion 23 where the coating resin 13 is burned out.
Is applied. Then, the deformed portion 23 on which the epoxy resin 22 is applied is put into a stainless steel pipe 21 made of stainless steel.
Fill and solidify 22.

"Problem to be Solved by the Invention" However, such a conventional fiberscope 1
In this case, when the epoxy resin 22 filled in the stainless steel pipe 21 of the deformed portion 20 is hardened, the contraction rate is large, and the stress caused by the contraction of the epoxy resin 22 on the deformed portion 23 of the image fiber 2 There is a problem that it takes.

Further, since the thermal expansion coefficients of the stainless steel pipe 21, the epoxy resin 22, and the image fiber 2 are significantly different, the deformed portion 23 of the image fiber 2 is inserted into the stainless steel pipe 21, and the epoxy resin 22 is filled in the stainless steel pipe 21. After curing and curing to form the deformed portion 20 of the fiberscope 1, if the ambient temperature changes, the deformed portion
There is a problem that a stress due to a difference in thermal expansion coefficient is applied to the deformed portion 23 of the image fiber 2 in 20 and the deformed portion 23 may be broken.

The present invention has been made in view of the above circumstances, and provides a fiberscope that can transmit a clear image without breaking a bent or twisted portion of an image fiber due to a temperature change. The purpose is to:

[Means for Solving the Problems] In the present invention, a part of a quartz-based image fiber is subjected to plastic deformation such as torsion or bending, and the deformed part is inserted into a ceramic pipe. The above object is achieved by filling an adhesive to reduce stress on the quartz image fiber due to a difference in thermal expansion coefficient between the ceramic pipe, the inorganic adhesive, and the quartz image fiber.

"Function" In a fiberscope with such a configuration, an inorganic adhesive is used instead of using an epoxy resin with a large shrinkage rate during curing, so it adheres to the image fiber when the adhesive is cured. There is no stress due to volume shrinkage of the agent. In addition, since the difference in thermal expansion coefficient between the quartz-based image fiber, the inorganic adhesive, and the ceramic pipe is smaller than that in the case of using a conventional epoxy resin and a stainless steel pipe, even if there is a temperature change, the image fiber may be bent or bent. The portion subjected to the torsion deformation does not break.

Hereinafter, the fiber scope of the present invention will be described with reference to FIGS.
This will be described in detail with reference to the drawings.

The difference between the fiberscope 30 of the present invention and the conventional fiberscope 1 shown in FIGS. 1 to 3 is that the deformed portion 20 has a deformed portion 23 of the image fiber 2.
Is inserted into a ceramic pipe 31 made of alumina, mullite, zirconia, etc. having excellent dimensional stability in place of the stainless steel pipe 21, and the inside of the ceramic pipe 31 is replaced with CaO, Al ₂ O instead of the epoxy resin 22. _This is a point filled with an inorganic adhesive 32 such as alumina cement containing ₃ as a main component.

Table 1 shows the thermal expansion coefficients of quartz glass, alumina ceramic, stainless steel, epoxy resin, and inorganic adhesive (alumina cement).

As shown in Table 1, the coefficient of thermal expansion of stainless steel is about 30 times that of quartz glass, whereas the coefficient of thermal expansion of alumina ceramic is about 9 times smaller. The thermal expansion coefficient of the agent is 1 /
3 to 1/5 or less.

Therefore, the image fiber 2
Stainless steel pipe whose deformed part 23 is made of stainless steel
Ceramic pipe such as alumina ceramic instead of 21
When the ceramic pipe 31 is filled with an inorganic adhesive 32 made of alumina cement or the like instead of the epoxy resin 22, stress generated due to a difference in thermal expansion coefficient due to a temperature change occurs in the conventional ceramic pipe 31. The stress can prevent the deformed portion 23 of the image fiber 2 from being broken by this stress.

"Example" The fiberscope 30 shown in Figs. 1 to 3 was prepared as follows.

The number of pixels (number of cores) is 30,000, fiber diameter 3mm, length 5m20c
The length of the image fiber on the eyepiece side is adjusted so that the length of the fiberscope is 5 m using an m image fiber.
Bending deformation was applied to a 20 cm portion.

As shown in FIG. 4, the deformation method is as follows. First, the coating resin 13 of the image fiber 2 is removed by burning using the oxyhydrogen flame burner 25, and then the portion composed of the clad 11 and the quartz jacket 12 is softened. The softened portion was subjected to the same plastic deformation as the deformed portion 23 shown in FIG.

Next, an alumina ceramic pipe 31 is placed over the deformed portion 23 of this bending, and
The inside of 31 was filled with an inorganic adhesive 32 containing alumina as a main component and cured. The thermal expansion coefficient of this inorganic adhesive 32 is 9 ×
It is 10 ^-6 .

Then, both ends of the image fiber 2 are mirror-polished, the bent portion is put in the eyepiece body 7, the other end is put in the objective body 5, and the end face 4a of the image fiber 2 on the object side is set. The objective lens 8 and the eyepiece 9 are mounted on the end face 6a side of the eyepiece side and the eyepiece side, respectively.
It was created.

In order to investigate the heat resistance of this fiberscope 30,
A heat cycle test was performed. Temperature range is -20 ° C to 80 ° C
The temperature was raised and lowered in 30 minutes, and 40 cycles were performed in one cycle for one hour.

After the heat cycle test, the image obtained by the fiber scope 30 was clear without any change compared to the image before the heat cycle test.

Further, the deformed portion of the fiber scope 30 was placed in a stainless steel pipe 21, and the inside of the stainless steel pipe 21 was filled with an epoxy resin 22 to prepare a fiber scope 1. The same heat cycle test as described above was performed. The bent portion 23 of the fiberscope 1 was cracked, and a part of the image obtained from the fiberscope 1 became dark and became invisible.

"Effect of the Invention" As described above, the fiberscope of the present invention
A part of the quartz-based image fiber is subjected to plastic deformation such as torsion or bending, and the deformed part is inserted into a ceramic pipe, and the inside of the ceramic pipe is filled with an inorganic adhesive. Since an inorganic adhesive having a small shrinkage ratio at the time of curing is used, no stress due to volume shrinkage of the adhesive is applied to the image fiber when the adhesive is cured. In addition, since the difference in thermal expansion coefficient between the quartz-based image fiber, the inorganic adhesive, and the ceramic pipe is smaller than when using a conventional epoxy-based resin and stainless steel pipe, the image fiber is not affected by changes in ambient temperature. Thus, a sharp image can be provided without breaking the bent or twisted portion.

[Brief description of the drawings]

1 to 3 show examples of a fiberscope according to the present invention. FIG. 1 is a longitudinal sectional view of the fiberscope, FIG. 2 is a sectional view of an image fiber used in the fiberscope, FIG. 3 is a cross-sectional view of a deformed portion of the fiberscope, and FIG. 4 is a schematic configuration diagram showing a method of deforming an image fiber using an oxygen-hydrogen flame burner. 2 ... image fiber, 23 ... deformed part, 30 ... fiberscope, 31 ... ceramic pipe, 32 ... inorganic adhesive.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02B 23/24-23/26

Claims (1)

(57) [Claims] 1. A part of a quartz-based image fiber is subjected to plastic deformation such as torsion or bending, and the deformed part is inserted into a ceramic pipe, and the inside of the ceramic pipe is filled with an inorganic adhesive, and the ceramic pipe is filled with an inorganic adhesive. A fiberscope characterized in that stress on a quartz-based image fiber due to a difference in thermal expansion coefficient between a pipe, an inorganic adhesive, and a quartz-based image fiber is reduced.