JPS589208Y2 - Endoscope - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a light guide illumination type endoscope.

Generally, in a light guide illumination type endoscope, a cover glass is provided in the distal end component, located in front of the exit end of the light guide fiber bundle for illumination, but in order to widen the viewing angle, the cover glass Those using concave lenses are often used.

When a concave lens is used as the cover glass, as shown in FIG. 1, the refractive index of light incident on the concave lens is large at the periphery and spreads sufficiently, but near the center the refractive index of light is small and the light does not spread much.

Therefore, in the observation field of view, the brightness at the periphery is insufficient compared to the brightness at the center, and uniform and sufficient brightness cannot be obtained over the entire observation range.

The present invention was developed based on the above-mentioned circumstances, and its purpose is to provide sufficient brightness to the periphery within the observation field of view, as well as to provide more uniform illumination. It's about providing a mirror.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

Reference numeral 1 in FIG. 2 is a distal end component of the endoscope 2, and the distal end of an illumination light guide fiber bundle 3 is guided to the distal end component 1.

An illumination window 4 is provided in front of the exit end of the illumination light guide fiber bundle 3, and a first cover lens 5 made of, for example, epoxy resin or glass is attached to this illumination window 4.

That is, the illumination window 4 is formed on the side surface of the tip component 1.

Further, an observation window 6 is formed on the side surface of the tip component 1, and a second cover lens 8 is formed in the observation window 6.
is installed.

Furthermore, a prism 9 is installed in the tip component 1 facing the observation window 6, and guides light entering from the observation window 6 to an objective optical system 10 in the tip component 1. There is.

The objective optical system 10 forms an image of the light entering from the observation window 6 on the distal end surface of the image guide fiber bundle 11.

On the other hand, the first cover lens 5 of the illumination window 4 is formed with a concave lens portion 12 as shown in FIG. 3, and the center portion 13 of this concave lens portion 12 is By integrally molding the portion 13 using a material having a higher refractive index than the peripheral portion, the portion 13 is formed to have a higher refractive index than the peripheral portion.

According to the above configuration, since the center portion 13 of the first cover lens 5 is formed to have a higher refractive index than the peripheral portion, the first cover lens is Light incident on the central portion of the lens 5 is largely refracted and sufficiently spread to the periphery.

Further, the light incident near the periphery of the first cover lens 50 is spread by the periphery of the concave lens portion 120.

Therefore, when the inside of the body cavity is illuminated, the brightness at the center of the observation visual field is somewhat reduced, but the brightness at the periphery increases, making it possible to make the brightness of the entire observation visual field more uniform.

In other words, the state can be made easy to observe.

Note that the present invention is not limited to the above-mentioned embodiment. For example, in order to increase the refractive index of the central portion 13 of the first cover lens 5, the cover lens 5 may be modified as shown in FIG. A hole 14 is formed in the center, and this hole 14
A cylindrical member 15 made of a material having a higher refractive index than the material of the cover lens 5 may be inserted into the cover lens 5 .

As described above, in the endoscope of the present invention, the central part of the cover lens installed in front of the exit end of the light guide fiber bundle for illumination has a higher refractive index than the peripheral part. It is possible to greatly refract the incident light and spread it sufficiently to the periphery.

Therefore, unlike conventional methods, where the center is extremely bright compared to the periphery and the periphery does not suddenly darken, the entire observation field can be made to have almost uniform brightness, making it easier to observe inside body cavities. This allows for easy lighting conditions.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the cover lens portion of a conventional endoscope, Fig. 2 is a sectional view of the distal end component of an endoscope showing an embodiment of the present invention, and Fig. 3 is a sectional view of the cover lens portion of the endoscope. FIG. 4 is a sectional view of a cover lens portion showing another embodiment of the present invention. 1...Tip component, 2...Endoscope, 3
...Light guide fiber bundle for lighting, 4...
・Illumination window, 5...Cover lens (first), 1
2... Concave lens part, 13... Center part (of cover lens), 14... Hole, 15...
···Element.

Claims (1)

[Scope of utility model registration request] An endoscope in which a cover lens is provided in the illumination window of the distal end component in front of the exit end of the light guide fiber bundle for illumination, characterized in that the refractive index of the central part of the cover lens is higher than that of the peripheral part. endoscope.