JPS59129819A - Endoscope photographing device - Google Patents

Abstract

PURPOSE:To prevent generation of moire fringes by placing a rough surface- shaped transparent plate for scattering light over a minute range, between an emitting end of a fiber and a prescribed image forming position, and equalizing a contrast of light and darkness caused by an array of the fiber. CONSTITUTION:An optical image is formed in front of a screen 16 by lenses 14, 15. The front of the screen is formed like a rough surface, therefore, together with an optical image of an object to be photographed 22, a straw bag piled-like pattern of an emitting end 23B of a fiber 23A is formed, but since light which is made incident to the rough surface is brought to irregular reflection over a minute area, respectively, a contrast of light and darkness in an expanse of about a radius of the fiber 23A is equalized, and the straw bag piled-like patterns scarecely appears on the surface of the screen 16, and accordingly, in case when this image is formed on the surface of a film having a color stripe structure by a lens 17, however the color stripe structure of the film 18 may be arrayed, moire fringes are prevented.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a camera that is attached to an endoscope having an image guide formed by bundling fibers and uses a recording medium having a predetermined arrangement such as a color stripe film. The present invention relates to an endoscope photographing device that can record images without causing moire fringes.

[Technical background of the invention and its problems] In recent years, by inserting an elongated insertion part into a body cavity, internal organs, etc. in the body cavity can be observed, and if necessary, treatment with forceps etc. inserted through a channel for a treatment instrument has become popular. 2. Description of the Related Art Medical endoscopes are widely used, which can collect in-vivo tissues and diagnose affected areas in detail. Also, in the industrial field, boilers.

Endoscopes are also used for maintenance purposes, such as observing the condition inside pipes of chemical plants and the like, or collecting and inspecting deposits on the pipe interior surface.

The above-mentioned endoscopes include flexible endoscopes that have a flexible insertion section and a bendable structure, and rigid endoscopes that have a rigid insertion section that is approximately linear.

These endoscopes include an illumination optical system that transmits illumination light supplied to the proximal side when the insertion section is inserted and emits the illumination light from the distal end of the insertion section to the object side, and the illumination optical system. An observation optical system is provided that can form an image of the object illuminated by the camera and observe it from behind the eyepiece on the hand side via an image transmission means (image guide).

Within the above softness? J) Mirrors generally use a fiber bundle in which flexible (for example, a circular cross section and a diameter of several tens of microns) extremely thin fibers are arranged in a stacked shape as an image guide. When stacked in bales,
Since the cross section of each fiber is circular, there is a part of each fiber that is not completely filled with fiber and transmits light, and a small gap that is not filled with fiber (this is a dark part because it hardly transmits light). ) are formed in a regular arrangement (hereinafter referred to simply as regularity of fiber arrangement unless there is a risk of mistake), but this dark region is small enough to be difficult to observe for normal observation. It's almost never a problem. Since the insertion section has a sufficiently flexible fiber bundle inserted through it, there is no need to provide an insertion hole in the abdominal wall as in the case of general rigid endoscopes, and the insertion section can be inserted into the oral cavity or other places. It can be directly inserted into the body cavity to the target site for observation.

When a camera as a photographing device is attached to the eyepiece of the above-mentioned flexible endoscope and an optical image of the target area (subject) is formed on the film loaded in the camera, the film is placed on a thin polyester base. ,green.

A striped filter of the three primary colors of blue is arranged repeatedly, for example, each stripe has a width of about 8 microns, and 394 sets of the three colors red, green, and blue are precisely arranged per 1 [cm]. The object imaged on the film is determined by the regularity of the arrangement of the fibers that transmit light and the minute dark areas where the fibers are not filled, and the regularity of the arrangement of the stripes on the film. Moiré fringes will occur in the optical image.

The manner in which such moire fringes occur depends on the arrangement of the image guide formed by the fiber bundle and the stripes on the film, that is, the relative angular position around the optical axis. It occurs strongly, but less strongly or not at all at other angles. Therefore, if the relative angle between the image guide and the camera as a photographing device is fixed at an angle that does not cause moire fringes, moire fringes will not appear in the photographed image.

However, when actually using an endoscope, the angular position of the endoscope with respect to the operator is not constant; for example, the operator operates the operating section, bending operating section, treatment instrument insertion section, etc. provided on the endoscope. The camera often gets in the way when doing so, and the position from which the camera is observed changes variously, so it is necessary to attach the camera so that it can rotate freely relative to the endoscope. Therefore, the relative angular position of the camera and the endoscope is arbitrary, and morea fringes will occur in the photographed image.

In this case, the operator observing through the finder directly observes the image formed on the stripe of the film. This results in observing an image formed at a position that is optically conjugate with (this position does not have an array of stripes, etc.). Therefore, the moiré fringes themselves and their intensity cannot be observed. Even if the target area was clearly captured through the viewfinder, moiré fringes would appear in the captured image, making the target area unclear.This diminished its value as a diagnostic document. Correct diagnosis may no longer be possible, or imaging may have to be taken again, placing a heavy burden or pain on the operator and the patient.

The effect of the moire fringes mentioned above cannot be known until after the film has been developed, so the operator has to check each frame individually to know whether the shooting is sufficient or not, which is extremely inconvenient. Met.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and an object thereof is to provide an endoscopic photographing device that can effectively prevent the occurrence of moire fringes on the film even when photographing. shall be.

[Summary of the Invention] The present invention provides an imaging device that is detachably attached to an eyepiece of an endoscope and has an image guide formed of a fiber bundle. An image is formed on a rough surface such as -H ground glass, and the image formed on this rough surface is further imaged on a recording medium such as a film having a structure such as a color stripe arranged at a predetermined imaging position. The structure is configured to prevent the occurrence of moiré fringes by placing a transparent plate with a roughened surface or a transparent plate containing fine particles with different refractive indexes between the exit end and the imaging position. There is.

[Embodiments of the invention] Hereinafter, the present invention will be specifically described with reference to the drawings.

Figures 1 and 2 relate to one embodiment of the present invention; Figure 1 shows the appearance of the embodiment together with a flexible endoscope, and Figure 2 shows the embodiment attached to the flexible endoscope. A schematic diagram of an optical system that forms an optical image of an object on a film surface having a color stripe structure arranged at a predetermined imaging position is shown.

As shown in Figure 1, flexible endoscope (fiberscope) 1
consists of an elongated and flexible insertion section 2, a large-diameter operation section 3 connected to the rear end of the insertion section 2, and an eyepiece section 4 formed at the rear end of the operation section 3. , extending to the outside from the side of the operation unit 3;
It is comprised of a flexible universal cord 5 attached with a connector that can be attached to a light source device (not shown).

In the insertion section 2, a distal end component section 7 housing an objective lens 6, etc., and a curved section 8 are sequentially connected from the distal end side, and a bending operation knob 9 formed on the operating section 3 can be rotated. By moving, the bending portion 8 can be bent horizontally or vertically.

A light guide fiber for transmitting illumination light is inserted into the universal cord 5, and the light guide fiber is bent by the operating section 3 and further inserted into the insertion section 2,
It is configured to emit illumination light in a viewing direction that can be observed by an objective lens 6 in the tip structure section 7.

Further, the operation section 3 is formed with a treatment instrument insertion section 10 such as forceps, and if necessary, a treatment instrument can be inserted through the treatment instrument insertion section 10 to collect tissue from the affected area and perform treatment such as diagnosis. It is now possible to do so.

On the other hand, the camera 11 as a photographing device is provided with a cylindrical portion 12 on the front end side of the camera body 13, which is formed with a mount that can be detachably attached to a mount provided at the rear end of the eyepiece section 4.

As shown in FIG. 2, a lens 15 for forming a real image behind the eyepiece lens 14 is housed inside the cylindrical portion 12 forming the mount, and these lenses 14. ．． A roughened screen 16 made of a transparent plate-like member such as ground glass with one surface roughened is disposed at the position where the image is formed by the screen 15 .

An imaging lens 17 is further disposed behind the screen 16, and a film 18 having a color stripe structure is placed at a predetermined imaging position in the camera body 13 where the image of the screen 16 is again formed. It is supposed to be located. This film 18 consists of red, green, and blue striped filters 18R and 18G on a polyester base 18A.
, 18B are formed, and silver halide grains 18C of the emulsion layer are formed above (behind) them.

The camera body 13 further includes a viewfinder 20.
(see FIG. 1) are formed, and the lens 17 and film 18
An optical image of the subject (object) is reflected by a return mirror (not shown) disposed between This return mirror is rotated and retracted in response to a photographing operation, and the light passing through the lens 17 is configured to form an image on the surface of the film 18.

The camera body 13 is normally rotatable relative to the cylindrical portion 12 in a rotation plane 21 shown in FIG.

Incidentally, the image guide 23, on which the optical image of the subject 22 is formed by the objective lens 6 on the distal end side of the insertion section 2, has fibers 23 each having a diameter of 12 microns, for example.
A is piled up in bales, and the entire circular cross section is formed to have a diameter of about 2.4 [mm]. Such an image guide 23 extends from the distal end portion 7 through the curved portion 8 and the insertion portion 2 and the operation portion 3 behind it to the eyepiece portion 4, and the rear end surface of the eyepiece portion 4, That is, as shown in FIG. 2, it is configured to transmit an optical image of the subject 22 formed on the tip surface to the exit end 23B.

This optical image is transmitted to the screen 16 by a lens 14.15.
The image is formed in front of the In this case, the front of the screen 16 (
In other words, since the surface facing the lens 14 and 15 is formed into a rough surface, the optical image of the subject 22 and the fiber 23
The stacked pattern of the output end 23B of the fiber A will be imaged, but since the incident light rays on the rough surface are each diffusely reflected over a minute area, the contrast of light and dark in the radius of the fiber 23A is A feature of this embodiment is that the structure is made uniform so that the stacked bale-like pattern on the screen 16 hardly appears.

Therefore, when an image that does not have a pattern such as the stacked bale pattern formed on the 16th surface of the screen is imaged by the lens 17 on the 18th surface of the film having a color stripe structure, how will the color stripe structure of the film 18 be formed? Even if the arrangement is simple, moiré fringes are prevented from occurring.

According to one embodiment configured in this way, each fiber 2
Image guide 23 formed by bundling 3A into a stacked shape, etc.
If the camera 11 of the first embodiment is attached to the flexible endoscope 1 using
Since the pattern A is designed not to appear, even if the camera 11 is loaded with the film 18 having a color stripe structure and a photograph is taken, moire fringes can be prevented from appearing.

As is clear from the above description, it is not the film 18 that is disposed at a predetermined imaging position, but a microscopic device having a photoelectric conversion function such as a C0D (charge coupled device), a BBD (bucket brigade device), or a MOS image sensor. One embodiment can also be applied to a solid-state image sensor formed by arranging a large number of light receiving elements.

In the above-mentioned embodiment, the rough screen 16 is integrally attached to the camera 11, but for example, a structure in which the cylindrical portion 12 can be detachably divided, that is, on the tip side of a normal camera, is used. Lens 1 in the above first embodiment
5. It has a (adapter) structure that accommodates the screen 16,
It is also possible to arrange for this adapter to be detachably interposed between the jacket portion 4 and the camera. By attaching the viewing device through this adapter, it is possible to prevent moiré fringes from occurring even when observing from the secondary eyepiece through an image guide made of bundled fibers.

Further, the screen 16 has the same function even if the rear surface (or both surfaces) are roughened instead of the front surface.

It should be noted that the screen 16 is not limited to the example in which the screen 16 is placed at the image formation position by the lenses 14 and 15;
and 17 (of course, the optimum roughness of the rough surface differs depending on the position), and the screen 16 (in this case, what is called a filter) is installed removably or integrally. ) When passing through the rough surface, each part has a uniform contrast of light and dark over a minute area,
The pattern on the exit end 23B of the fiber 23A appears, and it is also possible to eliminate it. Furthermore, substantially the same function can be obtained by disposing a transparent plate such as the screen 16 (filter) between the lens 17 and the image formation position by the lens 17 (also, the exit end 23B and the lens 14 The same function can be performed between

When using a transparent plate such as a filter as described above, it is not necessary to form an image once using the lens 15.

In short, a transparent plate (such as a screen 16 or a filter) with at least one surface roughened is disposed between the exit end 23B and the imaging position on the camera side to prevent the occurrence of moire fringes. This falls within the scope of the present invention. Furthermore, instead of using the above-mentioned transparent plate with a rough surface on at least one side, a large number of fine transparent particles having a refractive index different from that of the transparent plate material are mixed into an isometric transparent plate, and this transparent plate is placed in the middle of the optical path. When light passes through this transparent plate, it is refracted by the transparent particles so that the path is widened by a small angle, which equalizes the contrast between light and dark due to the fiber arrangement and prevents the occurrence of moiré fringes. It can also be configured to do so.

[Effects of the Invention] As described above, according to the present invention, a roughened transparent plate that scatters light over a minute range or a variable index of refraction is provided between the exit end of the fiber and a predetermined imaging position. The method is to arrange a transparent plate mixed with transparent particles to equalize the contrast between light and dark due to the fiber arrangement.
This has the advantage that even if a film having a structure such as a color stripe is disposed at the rear, the occurrence of moire fringes can be prevented. Further, the transparent plate has the advantage that it can be realized at low cost.

[Brief explanation of the drawing]

1 and 2 relate to one embodiment of the present invention, FIG. 1 is a perspective view showing the appearance of one embodiment, and FIG. 2 is a film arranged at a predetermined imaging position according to one embodiment. FIG. 2 is an explanatory cross-sectional view showing an optical system that forms an image. 1...Flexible endoscope 4...Eyepiece 6...Objective lens 11...Camera 12...Cylinder part
13..., camera body '14.15...
Lens 16...Screen 17...Lens
18...Film 23...Image guide 23A...Fiber 23B...Ejection end Fig. 1 Fig. 2

Claims (3)

[Claims] (1) In an endoscope having an image guide formed by bundling fibers, the proximal exit end of the image guide and a filter such as a color stripe in a camera that is removably attached to the eyepiece of the endoscope. between a predetermined imaging position where a solid-state imaging device formed by arranging a film having a structure or a light-receiving device having a photoelectric conversion function is arranged;
1. An endoscope photographing device characterized in that at least one surface is provided with a transparent plate having a rough surface or a transparent plate mixed with transparent particles having different refractive indexes. (2) The endoscopic photographing device according to claim 1, wherein the transparent plate is disposed in front of a predetermined image forming position at a position where the image of the exit end is once formed. (3) The endoscope according to claim 1, wherein the transparent plate is disposed at a position different from a position where an image of the exit end in front of a predetermined image forming position is once formed. Mirror photography device.