JPH06118313A - Light guide fiber for endoscope - Google Patents

Abstract

PURPOSE:To provide a light guide fiber for an endoscope which suppresses the attenuation of illumination light as much as possible, obtains the sufficient quantity of illumination light even by a small-diameter endoscope, reduces the diameter of the endoscope, and increases the quantity of illumination light for a large-diameter endoscope. CONSTITUTION:The light guide fiber which is arranged in the insertion part of the endoscope and transmits the illumination light is constituted by providing a coat layer 19 made of myristic acid having a lower refractive index than at least a clad layer 18 outside a light guide fiber 16 consisting of a core layer 17 and the clad layer 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide fiber for an endoscope which is disposed in an insertion portion of an endoscope and transmits illumination light.

[0002]

2. Description of the Related Art Generally, a light guide fiber bundle for transmitting illumination light is inserted into a distal end portion of an insertion portion of an endoscope. This light guide fiber bundle is inserted through a universal cord connected to the operation portion of the endoscope and guided to a connector, and the connector is provided with an incident end of illumination light.

The connector is connected to a light source device, and the illumination light emitted from the light source is transmitted from the incident end to the light guide fiber bundle, and is emitted from the emission end as an illumination window provided in the distal end constituent portion of the insertion portion. To be done.

This light guide fiber bundle is constituted by bundling a plurality of light guide fiber strands having a double structure of a core layer and a clad layer, and the fiber strands are
A method is known in which MoS ₂ (molybdenum sulfide) is applied as a solid lubricant in order to reduce friction between fiber strands.

Illumination light is totally reflected at the boundary surface between the core layer and the clad layer and transmitted inside the core layer, and is transmitted to the distal end portion of the insertion portion of the endoscope. Since the boundary surface has minute irregularities, part of the illumination light penetrates the boundary surface and enters the cladding layer. The illumination light that has entered the cladding layer strikes MoS ₂ applied to the surface of the light guide fiber element wire and is absorbed. That is,
The illumination light that has entered the light guide fiber bundle is partly M
The light is absorbed by oS ₂ , is dimmed, and is optically transmitted to the distal end constituent portion of the insertion portion.

[0006]

As described above, in order to avoid friction between fiber strands and prevent breakage, MoS ₂ is applied to the surface of the light guide fiber strands, and light that escapes to the cladding layer ( It is necessary to increase the number of fiber strands in order to obtain a sufficient amount of illumination light, by discarding (clad mode light) outside the fiber strands. There is a problem that it becomes thick.

The present invention has been made in view of the above circumstances, and its purpose is to guide light that penetrates the boundary surface between the core layer and the cladding layer and enters the cladding layer into the core layer again, An object of the present invention is to provide a light guide fiber for an endoscope that can transmit light and can obtain a sufficient amount of light with a small cross-sectional area.

[0008]

In order to achieve the above object, the present invention provides a coat layer having a refractive index lower than that of at least the clad layer on the outer side of the light guide fiber wire consisting of the core layer and the clad layer. The light escaping to the clad layer is guided again into the core layer for optical transmission.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows the entire endoscope 1. The endoscope 1 includes an insertion section 2 and an operation section 3, and the operation section 3 is provided with an eyepiece section 4. The insertion portion 2 is composed of a tip forming portion 5, a bending portion 6 and a flexible tube portion 7 from the tip thereof.

An image guide fiber bundle having an objective lens at its tip, a light guide fiber bundle, a channel tube (none of which are shown), and the like are internally provided inside the insertion portion 2. The image guide fiber bundle is guided to the eyepiece section 4 through the inside of the operation section 3. The light guide fiber bundle is inserted into the universal cord 8 extending from the side of the operation unit 3, and is guided to the light source connecting unit 9 at the tip of the universal cord 8. The channel tube communicates with a channel opening 10 provided on the tip side of the operation unit 3.

The insertion portion 2 and the channel opening portion 10 are arranged on a straight line, and the operation portion 3 on the base end side of the base end portion 11 having the channel opening portion 10 is arranged offset from the straight line. There is.

A rod-shaped hard mandolin 12 is removably inserted into the channel opening 10. From the channel opening 10 to the channel tube a rigid mandolin 12
In the inserted state, the bending portion 6 and the flexible tube portion 7 become a rod shape and are linearized by the hard mandolin 12. The channel opening 10 has a male luer lock shape, and the base end portion 13 of the rigid mandolin 12 has a female luer lock shape. Then, when the channel opening 10 and the base end portion 13 are engaged with each other, the distal end surface of the insertion portion 2, that is, the distal end surface of the distal end forming portion 5 and the distal end surface of the rigid mandolin 12 are configured to be aligned.

A bending operation portion 14 is provided in the operation portion 3, and the bending operation lever 1 provided in the bending operation portion 14 is provided.
The bending portion 6 can be bent by rotating the bending portion 5.

FIGS. 1 and 2 show one light guide fiber element wire 16 which is inserted into the insertion portion 2 and constitutes a light guide fiber bundle. The light guide fiber element wire 16 is composed of a core layer 17 and a cladding layer 18 provided outside the core layer 17, and the refractive index is such that core layer 17> cladding layer 18. The core layer 17 and the cladding layer 18 may be made of silica glass or multi-component glass, and the coating layer 1 may be provided outside the cladding layer 18.
9 is provided.

The coat layer 19 is a coat layer made of at least one of saturated higher fatty acid and alkyl polysiloxane, and is made of myristic acid, for example.
The refractive index has a relationship of core layer 17> cladding layer 18> coat layer 19. As the means for providing the coat layer 19, there are a dice coating method, a dipping method, a shower method and the like, but any method may be used.

As shown in FIG. 2, the light guide fiber element wire 16 having such a structure has a manufacturing irregularity 20 at the boundary surface between the core layer 17 and the cladding layer 18.
When the illumination light A that is transmitted while reflecting inside the core layer 17 is incident on the irregularity 20, the illumination light A enters the clad layer 18. However, since the coating layer 19 provided outside the cladding layer 18 has a lower refractive index than the cladding layer 18, the coating layer 19 is reflected at the interface between the cladding layer 18 and the coating layer 19 and reenters the core layer 17 to re-enter the core layer 17. The light is transmitted while being reflected inside the layer 17. Therefore, the light that has escaped to the cladding layer 18 (clad mode light) is not discarded to the outside of the light guide fiber element 16 as in the conventional case, and the cladding mode light can be used as a part of the illumination light.

Further, since myristic acid forming the coat layer 19 has lubricity, even when a large number of light guide fiber strands 16 are bundled into a light guide fiber bundle, there is little friction between the fibers and the fibers are broken. Can be prevented. .

As described above, the coat layer 19 is preferably translucent in order to suppress the attenuation of illumination light as much as possible. When a resin having no lubricity is used for the coat layer 19, the solid lubricant MoS ₂ may be applied between the light guide fiber strands 16 as in the conventional case.

[0020]

As described above, according to the present invention, at least the coat layer having a refractive index lower than that of the clad layer is provided outside the light guide fiber wire composed of the core layer and the clad layer. The light (clad mode light) leaked to the clad layer can be retransmitted to the core layer for optical transmission.

Therefore, the attenuation of the illumination light can be suppressed as much as possible, a sufficient illumination light amount can be obtained even with an endoscope having a small diameter, and the endoscope can be made thin. Further, in the case of an endoscope having a large diameter similar to the conventional one, the amount of light can be increased, so that there is an effect that the observability is improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a light guide fiber wire according to an embodiment of the present invention.

FIG. 2 is a vertical sectional side view of a light guide fiber element wire of the same embodiment.

FIG. 3 is a side view of the entire endoscope of the same embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Endoscope, 2 ... Insertion part, 16 ... Light guide fiber element wire, 17 ... Core layer, 18 ... Clad layer, 19 ... Coat layer.

Claims (1)

[Claims] 1. A light guide fiber, which is disposed in an insertion portion of an endoscope and transmits illumination light, has a refractive index at least outside the light guide fiber wire consisting of a core layer and a clad layer from the clad layer. A light guide fiber for an endoscope, which has a low coating layer.