JPH0233120A - Tip part of endoscope - Google Patents

Abstract

PURPOSE:To obtain a distinct observation image by providing an illumination window and an observation window by protruding them independently each other from the tip part main body, and also, bringing a transparent thin film into contact tensely and closely with the surface of both said windows. CONSTITUTION:A part of an illumination light emitted to the outside from an illumination window 3 is transmitted by repeating a reflection into a transparent thin film 14. However, since the transparent thin film 14 is hollowed between both windows 3, 4, as for a light beam which passes through its hollow 14a, its optical path length is extended markedly and the transmissibility of a light beam which reaches four pieces of observation windows drops. Also, since the hollow 14a is asymmetrical, the illumination light which has been emitted from the illumination window 3 varies its advance direction in a process for passing through the hollow 14a, and the greater part thereof goes out to the outside of the film as a light beam A, or said light becomes a light beam having an angle at which it is not made incident on the observation window 4 as a light beam B. Moreover, as for the transparent thin film 14, its wall thickness is thin, therefore, in order that the illumination light is transmitted by repeating its reflection, the number of times of reflection becomes very frequent. Accordingly, even if there is an illumination light for reaching the observation window 4, its intensity is attenuated by repeating the reflection, and does not obstruct actually the observation image.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to the distal end of an endoscope, and in particular, to the distal end of an endoscope. It's about the cover.

[Conventional technology]

At the distal end of the insertion section, an illumination window and an observation window are arranged side by side. The surfaces of these windows must be covered with transparent covers to prevent water from entering the endoscope from the outside. Conventionally, this transparent cover was provided independently on the surfaces of both the illumination window and the observation window.

[Problems to be Solved by the Invention] In recent years, the possibility of infection from patient to patient via endoscopes has attracted attention, and there is an increasing need to reliably prevent such infections.

One way to do this is to provide a watertight sheath that allows the insertion part of the endoscope to be inserted and removed freely, use the endoscope with the endoscope inserted inside the sheath, and then replace the sheath with a new one after use. One powerful method is to exchange. In this case, the sheath portions corresponding to the surfaces of the illumination window and observation window must be formed transparent.

However, if the surfaces of both windows are covered with one continuous transparent cover, for example, as shown in FIG.
The illumination light emitted from the endoscope's illumination window is repeatedly reflected within the transparent cover 102 and enters the observation window 103, causing ghosts and flares in the observation field. Since the light is extremely bright, the ghosts and flares that occur in this way are so intense that the endoscope becomes unusable. is weakened, and ghost images and flares are virtually no longer recognized. To do this, the distance between the windows can be increased, but
Since the tip of the endoscope inserted into the body diaphragm must be made as thin as possible, it is difficult to widen the distance between the windows.

Therefore, it is theoretically possible to create a structure in which only the part corresponding to the surface of the observation window and the part corresponding to the surface of the illumination window are made transparent within the two covers, and the space between them is made opaque to block the transmission of light. It is possible. However, due to the structure of an endoscope in which both windows each having a diameter of several millimeters are arranged close to each other, it would be extremely costly to manufacture only the surface portions of both windows to be formed independently and transparent. Furthermore, during use, problems such as misalignment occur between the transparent portion of the cover and both windows.

This invention eliminates such conventional drawbacks.

To provide a distal end part of an endoscope in which an illumination window and an observation window are covered with one continuous transparent cover and substantially no ghost or flare occurs in the observation field.

[Means for Solving the Problems] In order to achieve the above object, the distal end of the endoscope of the present invention has an illumination window for emitting illumination light and an observation window for introducing a light image into the objective optical system. In an endoscope disposed side by side on the tip body, the illumination window and the observation window are each independently provided to protrude from the tip body, and a transparent and malleable transparent thin film is provided between the two windows. It is characterized in that it is recessed in an asymmetrical shape and brought into close contact with the surfaces of both windows.

[Operation] A portion of the illumination light emitted from the illumination window is repeatedly reflected within the transparent thin film and transmitted within the transparent thin film. However, since the transparent thin film is recessed between both windows, the optical path length is significantly extended and the light transmission rate is reduced. Since the recess is asymmetrical, the direction of illumination light changes as it passes through the recess, and most of it exits outside the transparent thin film.
The rays become rays at an angle that does not enter the observation window.

In addition, the thin transparent thin film is stretched over both windows and becomes thinner and thinner, and the illumination light is reflected and propagated through it repeatedly, resulting in an extremely large number of reflections. Therefore, even if there is illumination light that reaches the observation window, its intensity will be attenuated by repeated reflections and become extremely weak.

In addition, since the transparent thin film is tightly attached to both windows,
Diffuse reflection does not occur between the window and the transparent WIll, and image distortion does not occur.

[Example 1 Examples will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the invention.

In the figure, 1 is a flexible tube that covers the insertion section of the endoscope, and 2
is a tip body connected to the tip portion thereof. A portion of the flexible tube 1 adjacent to the tip main body 2 is formed with a curved portion that can be bent freely by remote control, but the details thereof are omitted. On the front end surface of the tip main body 2, an illumination window 3 for emitting illumination light and an observation window 4 for introducing an optical image into the objective optical system are arranged side by side facing forward. The illumination window 3 and the observation window 4 are provided independently to protrude from the tip body 2. The exit end of the illumination optical fiber bundle 5 is disposed in the illumination window 3, a cover glass 6 is fitted in the observation window 4, and an objective lens 7 and an image transmission optical fiber bundle 8 are placed behind the observation window 4. The entrance end of the is disposed.

10 is a cylindrical sheath into which the flexible tube 1 can be inserted and removed. In this sheath 10, the outer peripheral portion of the distal end main body 2 is formed of a hard cylinder 11, and a flexible soft tube (not shown) is connected to the rear thereof. The inner surface of the cylindrical body 11 has a tip main body 2.
A click 13 is provided protrudingly to engage with a click groove 12 formed on the outer surface of the holder. The engagement between the click 13 and the click groove 12 connects the tip main body 2 and the cylindrical body 11 in a predetermined positional relationship.

A transparent thin sheet 115I14 made of a transparent and malleable synthetic resin made of, for example, polypropylene or polyethylene is watertightly attached to the front end surface of the cylindrical body 11.

The thickness of the transparent thin film 14 is, for example, about 0.05 l to 0.5 l. When the clicks 13 and the click grooves 12 are engaged, both windows 3.4 are pressed against the transparent thin film 14. As a result, the transparent thin film 14 is brought into tight contact with the surfaces of the windows 3.4, and is recessed asymmetrically toward the tip body 2 between the windows 3.4. This depression 14
The depth of a is preferably about 2 to 5 times the thickness of the transparent thin film 14.

In the embodiment configured in this manner, a portion of the illumination light emitted outward from the illumination window 3 is repeatedly reflected within the transparent thin sia and transmitted, as in the conventional case. However, since the transparent thin film 11114 is recessed between both windows 3.4, the optical path length of the light beam passing through the recess 14a is significantly extended, and the transmission rate of light reaching the observation window 4 side is reduced.

Since the recess 14a is asymmetrical, the illumination light emitted from the illumination window 3 is transmitted through the recess 14a as shown in FIG.
The direction of travel changes during the process of passing through the film, and most of the light ray A is shown by the dotted line in FIG. It becomes a ray of light. Also, it is transparent and thin! 1114 has a thin wall thickness, so the number of reflections becomes extremely large in order for the illumination light to be repeatedly reflected and transmitted within the thin transparent l1114. Therefore, even if there is illumination light that reaches the observation window 4, its intensity is attenuated by repeated reflections on the way, so that it does not actually interfere with the observed image.

Moreover, since the transparent 1fill 14 is tightly and closely contacted with both windows 3.4, diffuse reflection does not occur between each window 3, 4 and the transparent thin film 14, and image distortion does not occur.

FIG. 3 shows a second embodiment of the present invention, in which the thickness of the transparent thin film 24 is reduced at the asymmetrical depressions 24a. Such a thin wall portion may be formed by tensioning the transparent thin film 24, or may be formed by using a transparent thin film 24.
That part of the 1124 may be made thin from the beginning. If configured in this way, the angle at which most of the light rays do not enter the observation window 4, as shown in the light rays C and D shown in FIG. It becomes a ray of light.

Incidentally, a plurality of depressions 14a and 24a in each of the above embodiments may be formed.

[Effects of the Invention] According to the tip of the endoscope of the present invention, most of the illumination light that has entered the transparent thin film is extracted from the transparent thin film at the recessed portion of the transparent thin film, or at an angle that does not enter the observation window. Since the light ray has a value of , it almost never enters the observation window. Moreover, even if some illumination light reaches the observation window, its intensity is significantly weakened by repeated reflections within the transparent thin film, so ghosts and flares that interfere with observation do not occur, and the transparent S film I nervously pressed the window to both windows,
A clear observation image can be obtained with no diffused reflection or image distortion between the window and the transparent thin film. Moreover, since it is structurally extremely inexpensive, it has excellent effects such as being disposable.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of the first embodiment of the present invention, FIG. 2 is a partially enlarged view thereof, FIG. 3 is a partial sectional view of the second embodiment of the present invention, and FIG. 4 is a conventional FIG. 3 is a partial cross-sectional view of the distal end of the endoscope. 2... Tip body, 3... Illumination window, 4... Observation window, 11... Cylindrical body, l4, 24-... Transparent thin film, 1
4a, 24a... hollow.

Claims (2)

[Claims] (1) In an endoscope in which an illumination window for emitting illumination light and an observation window for introducing a light image into the objective optical system are arranged side by side on the distal end body, the illumination window and the observation window are each independently arranged as described above. An endoscope characterized in that a transparent thin film, which is provided to protrude from the tip body and is transparent and has malleability, is recessed in an asymmetrical shape between the two windows and brought into close contact with the surfaces of the two windows under tension. tip of. (2) The distal end portion of an endoscope according to claim 1, wherein the thickness of the transparent thin film is thinner at the recessed portion.