JPS6355684B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an endoscope with an improved illumination structure at its distal end.

The endoscope is equipped with an objective lens at the distal end of its insertion section, and a light guide fiber is inserted into the endoscope. Light is irradiated from the light guide fiber to the area to be inspected within the body cavity, and the reflected light is passed through the objective lens and image guide. It is designed to be sent to the eyepiece as an observation image via a fiber.

By the way, in order to improve the distribution of light emitted from the light guide fiber at the distal end of the insertion section of the endoscope, for example, as shown in FIG. A prism 2 is provided, and the prism 2 guides the light toward the objective lens 3 as shown by the arrow, or it surrounds the objective lens 3 as shown in FIGS. There is one in which a light guide fiber 1 is provided so that the entire light is guided toward the objective lens 3 side.

However, although the light distribution shown in Fig. 1 can improve the light distribution on the short distance side, it has the disadvantage that the light distribution on the long distance side becomes poor.
There is no particular problem with the one shown in the figure if it only has the image guide and light guide fibers, but if it has a forceps port, air supply port, and water supply port, the configuration of the tip becomes complicated, making it difficult to use. There was an inconvenience.

The present invention has been made focusing on the above circumstances,
The objective is to provide an endoscope that has a simple configuration and can distribute light well.

Hereinafter, one embodiment of the present invention will be described based on FIGS. 4 to 6. In the figure, reference numeral 11 denotes an operating section of the endoscope, and an eyepiece section 12 is connected to one end of the operating section 11, and an insertion section 13 is connected to the other end. Inside the insertion section 13, as shown in FIG.
5 has been inserted. Further, the distal end portion 13A of the insertion portion 13 is molded from a transparent member such as synthetic resin or glass, and has an air and water supply port 16 and a forceps port 17 formed therein as shown in FIG. An opaque lens frame 18 is also provided. A plurality of objective lenses 19 are disposed within the lens frame 18, and the lens frame 1
The end of the image guide fiber 15 is inserted into the optical fiber 8, and its entrance end face is connected to the objective lens 19.
They are spaced apart and facing each other. The objective lens 19 and the image guide fiber 15 constitute an observation optical system 20. Further, the injection end of the light guide fiber 14 is connected to the tip end 13 of the light guide fiber 14.
It is inserted and held in A.

In the above-described configuration, when the insertion section 13 of the endoscope is inserted into the body cavity and light is sent from the light source device (not shown) through the light guide fiber 14 and exited from the exit end surface, the light is emitted as shown in FIG. Then, as shown by the arrow in FIG. 6, it is diffused within the tip 13A and reaches the outer peripheral surface of the tip 13A. At this time, if the light impinges on the outer circumferential surface at an incident angle greater than a certain level, it will undergo total reflection on that surface and pass through the tip 13A again to be emitted from the end surface.
This light is irradiated onto the object in the body cavity, reflected, and then sent to the image guide fiber 15 via the objective lens 19, and then sent to the eyepiece 12 as an observation image.

As described above, since the light is reflected on the outer circumferential surface of the tip 13A, the tip 13A itself acts as a light emitter, and the distribution of light to the subject becomes almost uniform, making it possible to obtain good light distribution. .

In the above embodiment, the outer circumferential surface of the distal end portion 13A is formed linearly, but the outer circumferential surface of the distal end portion 13A may be formed curved as shown in FIG. 7 without being limited to this. good.

Further, as shown in FIG. 8, the outer circumferential surface of the distal end 13A may be protected by coating the outer circumferential surface of the distal end 13A with transparent synthetic resin 21 or glass having a different refractive index.

Furthermore, the end surface of the tip portion 13A is not limited to being flat, and may be arbitrarily changed.

As explained above, in the present invention, the distal end of the insertion section is made of a transparent member, and the light emitting end of the light guide fiber is held inside the transparent member, so that the light emitted from the light guide fiber is A part of the light is reflected by the outer peripheral surface of the tip, and the tip itself acts as a light emitter. Therefore, regardless of whether the distance between the tip and the object is short or long, the distribution of light hitting the object can be made almost uniform, resulting in better light distribution and a simpler structure. It is something to play.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing a first conventional example, FIG. 2 is a vertical sectional view showing a second conventional example, FIG. 3 is a front view thereof, and FIGS. Fig. 4 is a perspective view of the endoscope, Fig. 5 is a vertical sectional view showing the main parts, Fig. 6 is a front view thereof, and Fig. 7 is a first other embodiment. A longitudinal section showing an example,
FIG. 8 is a longitudinal sectional view showing a second alternative embodiment. 13...Insertion section, 13A...Distal end, 14...
Light guide fiber, 20... Observation optical system.

Claims (1)

[Scope of Claims] 1. An endoscope including a light guide fiber and an observation optical system at the distal end of the insertion portion, wherein the distal end is constituted by a transparent member held at the light exit end of the light guide fiber, An endoscope characterized in that the transparent member is provided with at least an observation optical system and an opening for an air/water supply passage. 2. The endoscope according to claim 1, wherein the transparent member has a two-layer structure with different refractive indexes.