JPS59881Y2 - light guide - Google Patents

Description

[Detailed description of the invention] This invention relates to an improvement of a light guide used in an endoscope.

Generally, a light guide is formed of a light transmitting fiber bundle in which a plurality of light transmitting fibers of the same length are bundled with their ends aligned and a base is fitted to the ends.

By the way, in an endoscope, light from an externally provided light source is sent into a living body cavity through a light guide.

For this reason, it is necessary to condense the light from the light source and make it efficiently enter the input end face of the optical transmission fiber bundle, but in reality it is difficult to focus the light from the light source only on the input end face of the optical transmission fiber bundle. The surrounding cap and the end face of the outer ring covering the outside of the cap are also irradiated.

Therefore, there is a problem that the base or the outer ring is heated by the light from the light source.

Conventionally, in this type of light guide, it is known that the ends of a bundle of light transmitting fibers are tied together with a base that is plated, and the outside is further covered with an outer ring.

However, in such a device, the reflectance of the end face of the cap to light is poor, so that the cap is heated by the light from the light source, and there is a problem in that the light transmission fiber bundle and the outer ring are burned out.

This invention was devised in order to solve such problems, and its purpose is to provide a light guide for an endoscope in which there is no risk of the base being heated by incident light.

An embodiment of this invention will be described below with reference to the drawings.

A light transmitting fiber bundle 1 is formed by aligning the ends of a plurality of light transmitting fibers 1a, and the light incident side end of the fiber bundle 1 is bound with a base 2.

The light transmission fiber bundle 1 bound with the cap 2 is further covered with a flexible outer ring 3.

Then, one side of the ring-shaped glass plate is coated with a metal such as silver or aluminum by vacuum evaporation on the end face portions of the base 2 and the outer ring 3 corresponding to the light incident side end faces of the light transmission fiber bundle 1. A mirror-finished reflector 4 is attached with its vapor-deposited surface 4a facing the base 2.

With such a configuration, when light is irradiated from a light source (not shown) as shown by the solid arrow in the figure, the light incident on the end face of the light transmission fiber bundle 1 is transmitted through the fiber bundle 1. At the same time, the light incident on the reflector 4 is reflected by the mirror surface.

The mirror surface of this reflector 4 is coated with metal by vacuum deposition, and has a reflectance of 97 to 99% for visible light to infrared light, so most of the light that enters the reflector 4 is reflected and only a small amount is reflected. Only 1-3% is absorbed and converted into heat.

This allows the light absorption rate to be reduced by several tens of minutes compared to the conventional chrome-plated cap exposed on the light incident side end face, and the cap 2 dissipates heat to the surroundings. Therefore, there is no risk that the cap 2 will be heated by the light emitted from the light source.

Therefore, there is no possibility that the optical transmission fiber bundle 1 and the outer ring 3 will be burnt out due to heating of the cap 2.

Furthermore, in this case, the mirror surface of the reflector 4 is not exposed to the outside but is placed on the end face side of the base 2 and the outer ring 3, so there is no risk of the mirror surface being damaged.

In the above embodiments, the reflector is made of glass, but it is needless to say that the reflector is not limited to this.

As detailed above, according to this invention, a reflector is attached to the end surface portion of the cap for binding the light incident side ends of the light transmitting fiber bundles, which corresponds to the light incident side end surface of the light transmitting fiber bundles. Therefore, it is possible to provide a light guide for an endoscope in which there is no risk of the base being heated by the incident light.

[Brief explanation of the drawing]

The figure is a sectional view showing an embodiment of this invention. 1... Light transmission fiber bundle, 2... Cap, 4
...Reflector.

Claims (1)

[Scope of utility model registration request] The light guide for an endoscope is configured to transmit light from an external light source into a living body cavity through a light transmission fiber bundle, and includes a cap for binding the light-incidence side end of the light transmission fiber bundle, and a cap for binding the light-incidence side end of the light transmission fiber bundle; an outer ring further covering the light transmission fiber bundle;
A light guide for an endoscope, comprising the outer ring and a reflector disposed on the light incident side end surface of the light transmission fiber bundle of the base.