JPS6290612A - Endoscope - Google Patents

Abstract

PURPOSE:To obtain a bright image by forming a body part and front end part of an endoscope in such a manner that both parts can be freely attached and detached and decreasing the optical coupling loss between the body part and front end part. CONSTITUTION:This endoscope is constituted of the body part 1 and the front end exchange part 2 which can be freely attachably and detachably attached to the front end of the body part 1. The body part 1 consists of an image fiber 3 to transmit the image, a light guide 4 which is disposed around the image fiber and transmits illuminating light, a covering 5 to protect the same and a coupling lens 6 attached to the front end of the image fiber 3. The front end exchange part 2 consists of a single-cored distributed index type image fiber 7, a light guide 8 provided to the outside periphery thereof and a metallic protective layer to protect the entire part of the front end exchange part 2. The light guide 4 of the body part 1 and the light guide 8 of the front end exchange part 2 are optically coupled via a circular conical prism 9. The single- cored distributed index type image fiber 7 transmits the image A at one end thereof and can form the real image A' at the other end with the above- mentioned constitution.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides an image fiber having an extremely thin tip.
In particular, it relates to endoscopes that are convenient for observing the inside of tooth root canals.

<Prior Art> Conventionally, as a dental root canal endoscope, the one shown in FIG. 4 is known. The conventional endoscope consists of an endoscope main body 10 and a distal end 11, as shown in FIG. 4, and the distal end 11 is made particularly thin for observation inside the root canal of a tooth. However, the image fiber that transmits the image of the observation target in the main body 10 and the light guide that transmits the illumination light are common to the image fiber and light guide of the tip 11, respectively, and the tip 11 needs to have a thin structure. The thickness of the protective layer is made as thin as possible. In FIG. 4, 12 is an eyepiece for observing images transmitted through the image fiber, and 17 is a joint with a light source that supplies illumination light to the light guide.

FIG. 5 is a configuration diagram showing the internal structure of the endoscope shown in FIG. 4. An image fiber 13 is inserted into the highly flexible endoscope main body 10 and distal end 11, and a light guide 14 for transmitting illumination light is arranged around the image fiber 13. An objective lens 15 is disposed at the tip of the image fiber 13, and an eyepiece 16 is disposed at the rear end of the image fiber 13. A joint 17 at the rear end of the light guide 14 is coupled to a light source and is supplied with illumination light. Illumination light supplied from the light source is transmitted through the light guide 14, exits from the tip, and illuminates the observation object. On the other hand, objective lens 1
The image grasped by the image fiber 5 is formed on the end face of the image fiber 13 and transmitted through the image fiber 13.

The image thus obtained on the rear end face of the image fiber 13 is magnified by the eyepiece 16 and can be observed visually.

<Problems to be solved by the invention> In the conventional endoscope shown in FIGS. 4 and 5, the main body 1
Since the image fiber 13 and the light guide 14 of the 0 and tip portion 11 are each formed integrally, if the thin tip portion is damaged, the entirety must be discarded, which is extremely uneconomical and expensive. Furthermore, since the tip 11 cannot be replaced, there is the inconvenience of having to thoroughly disinfect the tip for each patient, which is not sanitary. If the tip is replaceable, even if it breaks, only the tip needs to be replaced, which is economical. In addition, the tip can be replaced with a new tip for each patient, making it hygienic.

For this reason, development of a replaceable distal end has been considered, but this was difficult for the following reasons.

(1) Image fiber is a core that makes up a large number of pixels.
It consists of a fiber bundle with a cladding,
Since light passes only through the core, even if you cut the image fiber midway and interrupt the image with a lens, etc., the degree of coupling between the cores of the bundle fiber will be poor and the overall light intensity will drop, making the image dark and impractical. do not have.

(2) If the light guide was also cut in the middle and then joined, the light transmission was not good and the loss of light amount due to the connection was unavoidable. Because of the small diameter of the tip, for example, if the image fiber and light guide at the tip are smaller in diameter than those in the main body, optical coupling at the connection will be more difficult. Ta.

The present invention has been made in view of the problems of the prior art, and it not only has a structure in which the main body and the tip of the endoscope can be attached and detached, but also has a structure in which the tip has a single-core gradient index image fiber. Therefore, not only is the diameter extremely small, but the optical coupling between the image fibers and light guides between the main body and the tip is significantly improved, and coupling loss is significantly reduced, making it possible to obtain bright images.For example, inside a tooth root canal. The purpose is to provide an endoscope that is effective for observation.

Means for Solving the Problems> The configuration of the endoscope according to the present invention that achieves the above object includes an endoscope body having an image fiber and a light guide disposed around the image fiber, and an endoscope body having an image fiber and a light guide disposed around the image fiber. A gradient index image fiber detachably attached to the endoscope body and optically coupled to the image fiber; and a light guide disposed around the image fiber and optically coupled to the light guide. It is characterized by consisting of a tip exchange part equipped with.

<Example> An example of an endoscope according to the present invention will be described with reference to the drawings.

The endoscope according to the present invention includes an endoscope main body 1 and a tip exchange part 2 detachably attached to the distal end of the main body 1. The main body 1 includes an image fiber 3 consisting of an optical fiber bundle consisting of a multicore core and cladding for transmitting images, and a light guide 4 disposed around the optical fiber bundle for transmitting illumination light.
, a coating 5 for protecting these, - an image fiber 3
and a coupling lens 6 attached to the tip of the lens. The tip exchange part 2 includes a single-core gradient index image fiber 7 such as SELFOC fiber (trade name), a light guide 8 made by coating the outer periphery with a transparent material such as polymethyl methacrylate, polystyrene, etc. It consists of, for example, a metal protective layer that protects the entire tip exchange section 2. The light guide 4 of the main body 1 and the light guide 8 of the tip exchanging section 2 are optically coupled via a conical plate-shaped prism 9 provided in the tip exchanging section 2 of the main body 1. Incidentally, the image transmission pattern of the gradient index image fiber 7 used in the tip exchange section 2 is shown in FIG. As shown in FIG. 2, the single-core gradient index image fiber 7 can transmit an image A at one end and form the image as a real image A' at the other end. Furthermore, the relationship between the structure of the conical plate prism 9 used for coupling the light guide and the optical path is shown in FIGS. 3(a) and 3(b). Figure 3(b) is similar to Figure 3(a)
) is a sectional view showing the optical path of the device shown in FIG.

In addition, the tip exchange section 2 has a central gradient index image fiber 7 and a light guide 8 provided on its outer periphery. It is inserted into the connecting hole 5b of the tip 5a formed from the body. By inserting the tip exchange section 2 into the main body section 1, the image transmitted by the gradient index image fiber 7 is formed on the end surface of the image fiber 3 by the lens 6, and is transmitted to the eyepiece section. The graded index fiber 7 of the tip exchange section 2 has a refractive index distribution in the direction perpendicular to the axis and functions as a lens, and if it is too long, chromatic aberration will occur due to the difference in refractive index depending on the wavelength of light, but the chromatic aberration is noticeable. It is sufficient that the length is not too long.

In the above embodiment, the light guide 8 of the tip exchanging section 2 is made by coating the gradient index image fiber 7 with a transparent material layer. Even things are beautiful.

<Effects of the Invention> According to the endoscope according to the present invention, the structure is divided into a main body portion and an extremely thin tip exchange portion, and the optical coupling therebetween is excellent. Therefore, the inside of the tooth root canal can be easily observed.

In addition, the tip replacement part is removable, making it sanitary, and even if it becomes dirty or damaged, only the tip replacement part can be replaced, making it extremely economical. Further, in the present invention, since a single-core gradient index image fiber is used in the tip exchange section, the outer diameter of the image fiber can be made extremely small. It is now possible to observe bright images with a high degree of coupling at the connection between the main body and the tip without any problems with the connectivity between the pixels of the bundle fibers.

[Brief explanation of drawings]

Fig. 1 is a structural diagram of the distal end of the endoscope according to the present invention, Fig. 2 is a diagram illustrating image transmission of a gradient index image fiber, and Fig. 3 (a> is a plan view of a conical plate prism). , FIG. 3(b) is a sectional view showing the optical path of the endoscope shown in FIG. 3(a), FIG. 4 is an external view of a conventional endoscope, and FIG. 5 is an internal structural diagram of the endoscope shown in FIG. In the drawings, 1 is the main body, 2 is the tip replacement part, 3 is the image fiber,
4 is a light guide, 5 is a coating, 5a is an elastic tip, 5b
1 is a connecting hole, 6 is a lens, 7 is a gradient index image fiber, 8 is a light guide, and 9 is a conical plate prism. Figure 1 Figure 3 (a), (b)

Claims (2)

[Claims] (1) An endoscope main body having an image fiber and a light guide arranged around the image fiber, and an optical The apparatus is characterized by comprising a gradient index image fiber coupled to the image fiber, and a tip exchange section disposed around the image fiber and having a light guide optically coupled to the light guide of the main body section. Endoscope. (2) The endoscope according to claim 1, wherein a conical plate prism is disposed at an optical coupling portion between the light guide of the main body portion and the light guide of the tip exchange portion.