JP2008058432A - Image fiber, manufacturing method thereof, and fiberscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image fiber which is excellent in flexibility and an aperture ratio and has a function of magnifying a transmission image, to provide a manufacturing method thereof, and to provide a fiberscope. <P>SOLUTION: The image fiber is constituted so that a plurality of optical fibers are arranged inside a quartz jacket 4, a covering 3 is provided on the periphery of the quartz jacket 4, and on one side, there are provided a small diameter part 2a of which the outer diameter of the quartz jacket 4 is smaller than that on the other side and a tapered diameter part 2c of which the outer diameter of the quartz jacket 4 is gradually decreased toward the small diameter part 2a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image fiber used for medical use and industrial use in a narrow space or a bad environment, a manufacturing method thereof, and a fiber scope.

For example, image fibers are used for both medical and industrial purposes for observation in narrow spaces in body cavities such as blood vessels and urinary tracts, or for monitoring in adverse environments such as in high-temperature furnaces.
This image fiber is obtained by bundling a plurality of pixel fibers and fusing them together to separate the image formed on the end face of the image fiber into each pixel fiber and transmit it to the other end.

  Image fibers usually have a small overall length and the visible image becomes smaller, so it was necessary to enlarge the image on the eyepiece side, but for example, the outer diameter was gradually reduced from the eyepiece side toward the object side. By doing this, it is known that the outer diameter can be changed uniformly over the entire length, and the transmission image can be observed without enlarging using a lens or the like (for example, see Patent Document 1).

  Further, when observing the inside of a narrowly bent pipe line or when it is necessary to observe over a wide area, it is required to bend the tip on the objective side. Therefore, a technique is also known in which the thickness of the jacket portion at the tip of the image fiber is thinned by melting or grinding with hydrofluoric acid to reduce the wire diameter, thereby reducing the bending rigidity and improving the flexibility. (For example, refer to Patent Document 2).

JP-A-6-186484 JP 2004-53734 A

However, in order to change the outer diameter of the image fiber uniformly as in the technique described in Patent Document 1, it is difficult to manufacture a long one because the drawing speed is adjusted at the time of manufacturing the image fiber. Met. In addition, since the outer diameter is changed uniformly, the shape of the sleeve used to attach the lens to the tip must also be changed uniformly according to the image fiber, increasing the cost. I will invite you.
In addition, in this image fiber, since the outer diameter is reduced toward the objective side, the aperture ratio at the end portion on the objective side is lowered.

  Further, in Patent Document 2, since the diameter is not reduced sequentially toward the objective side, the aperture ratio does not decrease, but the image fiber itself does not have a transmission image enlargement function, and a lens or the like is used on the eyepiece side. It was necessary to enlarge the transmission image. At this time, depending on the attachment of the eyepiece side lens, the image may be distorted or the center may be displaced.

  An object of the present invention is to provide an image fiber having a good flexibility and an aperture ratio, and having a transmission image enlargement function, a manufacturing method thereof, and a fiberscope.

  An image fiber according to the present invention capable of solving the above-mentioned problems is an image fiber in which a plurality of pixel fibers are arranged inside a quartz jacket, and a coating is provided on the outer periphery of the quartz jacket, A small-diameter portion having a smaller outer diameter of the quartz jacket and a constant outer diameter than the other end side, and a reduced-diameter portion in which the outer diameter of the quartz jacket gradually decreases toward the small-diameter portion on one end side of the fiber; It is characterized by having.

  Further, the outer diameter of the quartz jacket in the small diameter portion is 60% or more and 95% or less of the outer diameter of the quartz jacket on the other end side, and the length of the reduced diameter portion is 100 mm or more and 200 mm or less. It is preferable.

  Moreover, it is desirable that the length of the small diameter portion is 1 mm or more and 50 mm or less.

  An image fiber manufacturing method according to the present invention that can solve the above-mentioned problems is a method of manufacturing the image fiber according to the present invention, wherein a step of removing a part of the coating of the image fiber, A step of heating and stretching the quartz jacket from which the portion has been removed to form the reduced diameter portion and the small diameter portion, and a step of providing a coating on the outer periphery of the reduced diameter portion and the small diameter portion. To do.

  The fiberscope according to the present invention is characterized in that a lens is provided on the one end side of the image fiber.

  According to the present invention, since the outer diameter of the quartz jacket gradually decreases toward the small diameter portion formed on one end side of the image fiber, the flexibility on the one end side (object side) is obtained. In addition, a transmission image enlargement function can be provided without using a lens or the like on the eyepiece side. In addition, the small diameter portion having a constant outer diameter provided on the one end side can ensure a good aperture ratio at the end surface on the one end side, and can capture images well.

Hereinafter, an example of an embodiment of an image fiber, a manufacturing method thereof, and a fiberscope according to the present invention will be described with reference to the drawings.
FIG. 1 is a partial cross-sectional view showing a fiberscope using an image fiber according to the present embodiment, and FIG. 2 is a partial cross-sectional view of a distal end portion of the fiberscope.

As shown in FIG. 1, the fiberscope 1 includes an image fiber 2. This image fiber 2 is an image fiber (image guide) called a multi-core fiber type, in which a plurality (thousands to tens of thousands) of pixel fibers are arranged inside a quartz jacket, and the outer periphery of the quartz jacket Has a structure in which a coating 3 is provided. Each pixel fiber is a glass fiber having a core and a clad, and forms an independent optical line. In FIG. 1, the left side is the eyepiece side, the right side is the objective side, and the light incident on the objective-side pixel fiber end face is emitted from the eyepiece-side pixel fiber end face, whereby the objective-side image is observed on the eyepiece side. Be able to.
The coating 3 is formed of a thermosetting resin such as polyimide resin or silicon resin, or an ultraviolet curable resin.

The image fiber 2 according to the present embodiment includes a small-diameter portion 2a having an outer diameter smaller than that of the eyepiece side and having a substantially constant outer diameter at the end portion on the objective side. .
The image fiber 2 has a reduced diameter portion 2c formed by gradually reducing the outer diameter of the quartz jacket from the normal diameter portion 2b on the eyepiece side toward the small diameter portion 2a. The normal diameter portion 2b excluding the small diameter portion 2a and the reduced diameter portion 2c has a substantially uniform outer diameter.

Here, the outer diameter of the quartz jacket in the small diameter portion 2a is preferably 60% or more and 95% or less with respect to the normal diameter portion 2b, and the axial length of the small diameter portion 2a is as follows. It is set within a range of 1 mm or more and 50 mm or less.
Further, the length of the reduced diameter portion 2c in the axial direction is set within a range of 100 mm to 200 mm.

The objective side of the image fiber 2 formed as described above is a scope unit 10 as shown in an enlarged view in FIG. The scope unit 10 includes a cylindrical lens holder 11 and a lens 12 fitted to one end side (right end side in FIG. 2) in the lens holder 11. The lens 12 can be a collimating lens, a cylindrical lens, or the like.
The small-diameter portion 2a of the image fiber 2 is fitted and fixed to the other end side (left end side in FIG. 2) of the lens holder 11, whereby the lens 12 is disposed on the end surface of the image fiber 2. ing. Note that the end face of the image fiber 2 and the lens 12 may be bonded and fixed to each other with an adhesive containing a refractive index matching agent.

  According to the image fiber 2 configured as described above and the fiberscope 1 using the image fiber 2, the reduced diameter portion 2c is provided in which the outer diameter of the quartz jacket gradually decreases from the normal diameter portion 2b toward the small diameter portion 2a on the objective side. Therefore, the image fiber 2 on the objective side can be easily bent. In addition, a transmission image enlargement function can be provided without using a lens or the like on the eyepiece side. Furthermore, since the end on the objective side is the small-diameter portion 2a and the outer diameter is constant, it is possible to ensure a good aperture ratio NA (for example, 0.3 or more) at the end face, and to obtain a good image. Can be captured.

  In particular, the outer diameter of the small-diameter portion 2a is 60% or more and 95% or less of the outer diameter of the normal-diameter portion 2b. Regardless of the diameter tolerance (for example, about ± 5%), a good enlargement function can be ensured. Moreover, since the length of the reduced diameter part 2c is 100 mm or more and 200 mm or less, the length which has the favorable flexibility requested | required in the objective side of the image fiber 2 is securable.

  In addition, since the length of the small-diameter portion is 1 mm or more and 50 mm or less, the distal end portion bent at the time of observation requires a certain length, for example, the inside of the human alveoli can be observed well. it can.

Next, a method for manufacturing the image fiber 2 constituting the fiberscope 1 will be described.
First, a plurality of glass pixel fibers having a core and a clad are aligned and bundled to a predetermined length, and are accommodated inside a cylindrical quartz jacket. Then, the pixel fiber together with the quartz jacket is heated and melted to integrate the plurality of pixel fibers and the quartz jacket. This is the base material of the image fiber. The base material is drawn to reduce the diameter so that it has a predetermined diameter, and through the resin coating die, the thermosetting resin such as polyimide resin or silicon resin or UV curable resin is placed on the outer peripheral side. A coating 3 made of resin is applied. As a result, an image fiber having a uniform outer diameter corresponding to the normal diameter portion 2b is obtained.

Next, as shown in FIG. 3, a part of the coating 3 on the object side of the image fiber 2A having a uniform outer diameter is removed, and the quartz jacket 4 is exposed.
Here, the length of the covering 3 to be removed is preferably about 5 mm longer than the total length of the small diameter portion 2a and the reduced diameter portion 2c to be formed.

Thus, when the objective-side coating 3 is removed, as shown in FIG. 4, a weight M having a predetermined weight is suspended from the objective side of the image fiber 2A, and the portion from which the coating 3 of the image fiber 2A has been removed (that is, The exposed portion of the quartz jacket 4 is heated by the heater H.
In this way, the quartz jacket 4 on the objective side from which the coating 3 of the image fiber 2A has been removed and the plurality of pixel fibers inside thereof are softened by the heat of the heater H, so that the object is stretched downward by the load of the weight M. Thus, a small diameter portion 2a having a constant outer diameter and a gradually reduced diameter portion 2c are formed.
Thereafter, a coating 3 is formed by spraying and applying a thermosetting resin such as polyimide resin or silicon resin or an ultraviolet curable resin to the portion of the image fiber 2A from which the coating 3 has been removed.

  According to the above manufacturing method, it is excellent in flexibility and aperture ratio without performing control to change the drawing speed at the time of drawing the base material of the image fiber with high accuracy, and has a good image enlargement function. Can be manufactured very easily, and the quality and cost of the image fiber 2 can be improved.

It is a fragmentary sectional view showing an embodiment of a fiberscope using an image fiber concerning the present invention. It is a fragmentary sectional view of the front-end | tip part of the fiberscope of FIG. It is a partial side view of the image fiber which shows the manufacturing process of the image fiber which concerns on this invention. It is a side view which shows the manufacturing process of the image fiber which concerns on this invention. It is a side view which shows the manufacturing process of the image fiber which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fiberscope 2, 2A Image fiber 2a Small diameter part 2c Reduced diameter part 3 Coating | coated 12 Lens

Claims (5)

A plurality of pixel fibers are arranged inside a quartz jacket, and an image fiber having a coating provided on the outer periphery of the quartz jacket,
One end side of the image fiber, a small diameter portion having a smaller outer diameter and a constant outer diameter than the other end side, and a reduced diameter in which the outer diameter of the quartz jacket gradually decreases toward the small diameter portion. And an image fiber. The image fiber according to claim 1,
The outer diameter of the quartz jacket in the small diameter portion is 60% or more and 95% or less of the outer diameter of the quartz jacket on the other end side, and the length of the reduced diameter portion is 100 mm or more and 200 mm or less. Characteristic image fiber. The image fiber according to claim 1 or 2,
The image fiber, wherein the length of the small diameter portion is 1 mm or more and 50 mm or less. A method for producing an image fiber according to any one of claims 1 to 3,
A step of removing a part of the coating of the image fiber, a step of heating and stretching the quartz jacket of the part from which the coating has been removed to form the reduced diameter portion and the small diameter portion, and the reduced diameter portion and the small diameter portion. And a step of providing a coating on the outer periphery of the image fiber.   A fiberscope comprising a lens on the one end side of the image fiber according to any one of claims 1 to 3.

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