JPH0785127B2 - Endoscope device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used for an endoscope having an image guide formed by bundling fibers, and prevents moire fringes from occurring to enable clear imaging or observation. The present invention relates to an endoscope device.

[Problems to be Solved by Conventional Techniques and Inventions] In recent years, by inserting an elongated insertion portion into a body cavity, an organ in the body cavity or the like is observed, and forceps or the like inserted through a channel for a treatment tool as necessary. 2. Description of the Related Art A medical endoscope capable of collecting in-vivo tissue and making a detailed diagnosis of an affected area by using the treatment tool is widely used. Also in the industrial field, endoscopes are used for maintenance such as observing the condition inside pipes of boilers, chemical plants, etc., or collecting and inspecting the deposits on the pipe inner surface.

The endoscope includes a flexible endoscope having a flexible insertion portion and a bendable structure, and a rigid endoscope having a substantially straight insertion portion.

In these endoscopes, when the insertion section is inserted, an illumination optical system that transmits the illumination light supplied to the hand side and emits the illumination light from the tip side of the insertion section to the object side, and the illumination optical system. An observation optical system is provided which can form an image of the object illuminated by the object and observe it from the rear of the eyepiece on the hand side through an image transmitting means (image guide).

The flexible endoscope generally uses a flexible fiber bundle (for example, a circular cross section and a diameter of about 10 μm) as an image guide, which is a fiber bundle in which a bundle of fibers is arranged. When stacked in a bale, the cross-section of each fiber is circular, so the fiber cannot be completely filled with light, and each fiber part that transmits light and the minute voids that are not filled with fiber Since it does not transmit, it becomes a dark part, and at the end part it is fixed with an adhesive such as acid solute glass.) And it will be formed in a regular arrangement, but since this dark part is small enough for normal observation Is almost never a problem. Since the insertion portion is such that the fiber bundle having sufficient flexibility is inserted, without inserting a hole for insertion into the abdominal wall as in the case of a general rigid endoscope, Can be directly inserted to a target site in the body cavity through a curved path to be observed.

By the way, when an imaging device is attached to the eyepiece of the flexible endoscope and an image transmitted by the image guide is to be captured, moire fringes may occur due to the configuration of the imaging device. For example, in a photography device, a striped filter of three primary colors of red, green, and blue is arranged on a thin polyester base as a film, and light passing through this filter is received by a photoconductor. There is something.
The width of each stripe of this filter is, for example, about 8 microns, and 394 sets of three colors of red, green, and blue are regularly arrayed per 1 cm, and the width of the fiber forming the image guide is They have about the same size. For this reason, the array pattern formed by the light-transmitting fiber of the image guide and each of the fibers and the minute dark portion not filled with the fiber interferes with the array pattern of the stripes of the filter to bond to the film. Moire fringes will occur in the optical image of the imaged subject.

Since the manner of generating such moire fringes differs depending on the shape and relative positional relationship between the fiber array pattern and the filter stripe array pattern, the occurrence state of the moire fringes changes when the camera is rotated around the optical axis. . Therefore, if the relative angle between the image guide and the camera is fixed to a specific angle, image distortion due to moire fringes may be reduced in some cases.

However, when the endoscope is actually used, the angle position of the endoscope with respect to the operator is not constant, and for example, the operation unit, the bending operation unit, the treatment instrument insertion unit, etc. provided on the endoscope are operated. The camera often becomes obstructive when doing so, and the position at which the camera's finder is observed also changes, so the camera must be mounted so that it can freely rotate with respect to the endoscope. Therefore, the relative angular position between the camera and the endoscope is arbitrary and moire fringes are generated in the captured image.

In this case, the operator observing from the viewfinder does not directly observe the image formed on the film stripe, but is reflected by the return mirror on the endoscope side (that is, the front side) of the film, and the film position is changed. The image formed at a position optically conjugate with (this position does not have an array such as stripes) is observed. Therefore,
Since the moiré fringe itself and the degree of its intensity cannot be observed, even when the image was captured with the target part clearly captured from the viewfinder, the moiré fringe appeared in the captured image and the target part was sometimes unclear. .

Further, similarly to the above, when a viewing device having an image guide fiber bundle is attached to the eyepiece part of the flexible endoscope and an object image is observed on the viewing side, the image guide of the endoscope and the fiber of the image guide of the viewing device are There is a problem in that the array patterns interfere with each other to produce moire fringes on the screen.

The method of generating such moire fringes depends on the shape and the positional relationship of the array pattern of the fibers of the two image guides, and when the two image guides are relatively rotated about the optical axis, a certain specific pattern is generated. Moire fringes are strongly generated at angles, but moiré fringes are not so much generated at other angles. Therefore, if the endoscope and the viewing device are set at a specific angle, the image distortion due to the moire fringes is reduced.

However, when actually using the endoscope, the angle of the endoscope with respect to the operator is not constant, and for example, when operating the operation unit, the bending operation unit, the treatment instrument insertion unit, etc. provided in the endoscope. Since the viewing device often becomes an obstacle and the position to be observed by the viewing device changes variously, it is necessary to mount the viewing device so that it can freely rotate with respect to the endoscope. Therefore, the relative angle between the endoscope and the viewing device is arbitrary, and moire fringes are generated in the image.

In order to solve this problem, by providing an optical filter that gives a phase difference of 1/2 of the wavelength of light between the image guide of the endoscope and the image guide of the viewing device, the occurrence of moire is prevented. It has been proposed by JP-A-55-143125. However, this type of optical filter has a characteristic that the spatial frequency response is gently lowered, and thus there is a problem that the resolution is deteriorated more than necessary.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and effectively prevents the generation of moire fringes in an image while maintaining a good resolution, and further, in the case of shooting, the deterioration of the image quality due to the moire fringes is caused. It is an object of the present invention to provide a reduced endoscope apparatus.

[Means for Solving the Problems] One of the present invention is an objective lens, and an image guide fiber bundle that receives an object image formed by the objective lens at an incident end surface and transmits the object image to the exit end side. An image forming lens for forming an image transmitted to the exit end side of the image guide fiber bundle, and an image formed by the image forming lens behind a filter in which regions of different colors are regularly arranged. An image pickup device for picking up an image of an object by being received by an image receiving unit composed of a light-sensing unit arranged, and an optical filter formed of a birefringent plate provided in an optical path from the exit end face of the image guide fiber bundle to the image receiving unit. Further, two are provided: an objective lens, and an image guide fiber for receiving an object image formed by the objective lens at an incident end surface and transmitting the object image to the exit end side. A bundle, an imaging lens for forming an image transmitted to the exit end side of the image guide fiber bundle, a second image guide fiber bundle for receiving the image formed by the imaging lens, The optical filter comprises a birefringent plate provided in the optical path from the exit end face of the image guide fiber bundle to the second image guide fiber bundle.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the appearance of one embodiment of the present invention, and FIG.
FIG. 3 shows the periphery of the eyepiece of the flexible endoscope, which is the main part of the embodiment, and the optical system of the camera attached to the eyepiece. FIG. 3 shows the emission of the fiber imaged on the film surface of FIG. The state of the edge is shown.

As shown in FIG. 1, a flexible endoscope (fiberscope) 1
Is an elongated and flexible insertion part 2, a large-diameter operating part 3 connected to the rear end side of the inserting part 2, and an eyepiece part 4 formed on the rear end side of the operating part 3. , Extended to the outside from the side of the operation unit 3,
The flexible universal cord 5 is provided with a connector that can be attached to a light source device (not shown).

The insertion section 2 is provided with a distal end constituting section 6 accommodating an objective optical system and the like, and a bending section 7 sequentially connected from the distal end side,
By rotating the bending operation knob 8 formed on the operation portion 3, the bending portion 7 can be bent in the left-right direction or the up-down direction.

A light guide fiber for transmitting the irradiation light is inserted into the universal cord 5, and the light guide fiber is curved by the operating portion 3 and further inserted into the insertion portion 2,
It is configured so that the illumination light is emitted in the direction of the visual field in which the observation can be performed by the objective optical system in the tip forming unit 6.

Further, a treatment tool insertion portion 9 such as forceps is formed in the operation portion 3, and a treatment tool is inserted from the treatment tool insertion portion 9 to collect a diseased tissue to perform a treatment such as diagnosis as necessary. You can do it.

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

A lens 14 is housed inside the cylindrical portion 12 forming the mount as shown in FIG. 2 (in FIG. 2, a single lens including the eyepiece lens in the eyepiece portion 4 is shown). ,
Film loaded in the imaging position where the image is formed by the lens 14.
It is designed to face 15 sides. In this film 15, red, green and blue stripe filters 15R, 15G and 15B are formed on a polyester base 15A, and silver halide grains 15C of an emulsion layer are formed thereon (rear).

A viewfinder 16 (see FIG. 1) is further formed on the camera body 13, and the incident light is (normally) reflected by a return mirror (not shown) arranged between the lens 14 and the film 15 to form a film. It is possible to observe the optical image of the subject formed at a position optically conjugate with the image forming position where the 15 surface is located.This return mirror is rotated and retracted by the photographing operation, and passes through the lens 14. The light is configured to be imaged on the surface of the film 15.

The camera body 13 can rotate with respect to the cylinder 12 on a rotation surface 17 shown in FIG.

By the way, the image guide 18 on which the optical image of the subject is formed on the tip surface of the objective optical system on the tip side of the insertion section 2.
Is a stack of fibers 18A with a diameter of 12 microns,
The entire circular cross section is formed to have a diameter of about 2.4 [mm]. Such an image guide 18 is extended from the rigid tip portion 6 to the curved portion 7, the insertion portion 2 and the operation portion 3 behind the curved portion 7, and the eyepiece portion 4 to form an optical image formed on the distal end surface. The rear end surface of the eyepiece 4, that is, the exit end 18B as shown in FIG. Birefringent element 19 formed by cutting into a shape
Are fixed by a mounting bracket 20 having an opening window.

The birefringent element 19 has a refractive index having optical anisotropy due to a crystal structure, and when a light ray is incident perpendicularly on the plate surface cut out so that the principal axis of the crystal is not perpendicular to the plate surface, A ray called an ordinary ray that travels straight in a direction and an extraordinary ray that bends and travels are separated, and after passing through a crystal, both rays have a characteristic of being parallel to each other.

The birefringent element 19 selects the thickness of the plate surface to an appropriate value according to the size of the birefringence, and rotates the plate surface (when fixing), for example, as shown in FIG. As shown, the optical image O of the phi 18A formed on the surface of the film 15 by the ordinary ray and the fiber 18A formed by the extraordinary ray.
The optical image (shown by the broken line) E of the fiber 18A is displaced by about the radius of the fiber 18A, and the fiber 18
It is fixed so that the center of the optical image E of the fiber 18A due to the extraordinary ray coincides with the place where (an image of) a dark portion other than A is formed.

By doing so, the difference in contrast between the bright image of the fiber 18A and the image of the dark part not filled with the fiber 18A (most of the image) is substantially eliminated. One of the features of the first embodiment is that even if there is a structure such as a stripe on the film 15 side, a means for forming almost no moire fringes is formed.

According to one embodiment of the present invention having such a configuration, when observed from the eyepiece 4 of the flexible endoscope 1 to which the birefringent element 19 is attached, it is slightly deviated by the birefringent element 19 and observed. However, since the amount of the deviation is a sufficiently small amount, there is no practical problem.

On the other hand, when the camera 11 as a photographing device is mounted and photographing is performed, the film is passed through the birefringent element 19 as described above.
The optical image formed on the fifteenth surface has a contrast difference between a bright portion where the light of each fiber 18A is transmitted and a dark portion where the fiber 18A is not filled (most of them) due to a double image of ordinary rays and extraordinary rays. Is almost eliminated, the occurrence of moire fringes that normally occurs due to the regularity of the array of the fibers 18 and the regularity of the array such as the stripes of the film 15,
It can be prevented without having much relation to the arrangement of the stripes of the film 15.

According to the first embodiment, when the camera 12 is mounted and observed from the viewfinder 16 (in this case, the camera body 13 may have an arbitrary (rotation) angle with respect to the flexible endoscope 1 side), Optical image O by ordinary ray and fiber by extraordinary ray
If the optical image E of the exit end 18B of 18A is in a state of being observed as shown in FIG. 3, for example, even if the camera body 13 side is rotated by an arbitrary angle and photographed, moire fringes are generated. Can be prevented.

Therefore, according to one embodiment of the present invention, the fiber 18A observed from the viewfinder 16 before the actual shooting is performed.
By checking whether the double image of the exit end 18B of the is set as described above, when actually taking a picture, even if the camera main body 13 side is rotated by an arbitrary angle, a moire fringe is formed in the taken image. You can know that it will not occur and you can shoot with confidence.

Further, as described above, regardless of the angle of the camera body 13, it is possible to know whether or not moire fringes may occur in the captured image by observing from the viewfinder 16, so that the birefringent element 19 can be used as a fiber. It does not have to be integrally fixed to the injection end 18B of 18A, but may be configured to be removable.

Further, the position where the birefringent element 19 is fixed or detachably attached does not have to be provided so as to be in contact with the emission end 18B, but between the emission end 18B and the film 15 and the camera body. Any portion that does not rotate with the portion 13 may be used. In this case, if the flexible endoscope 1 is fixedly attached to the side of the flexible endoscope 1 (rearward from the exit end 18B), it is possible to prevent the generation of moire fringes regardless of the state of the photographing device. or,
The structure may be detachably attached between the flexible endoscope 1 and the camera, that is, the mount portion of the eyepiece 4. In this case, it needs to be adjusted, but with a scale on the outer circumference (without observing from the viewfinder 16)
The structure can be easily set to an appropriate angle, or the structure can be attached only at the appropriate angle position. Further, the birefringent element 19 may not be attached to the flexible endoscope 1 side, but may be attached to the camera 11 side, for example, a mount portion or any other portion in front of the rotation surface 17. In this case, when it is attached to the eyepiece, it is necessary to adjust whether the attachment angle is an appropriate angle. However, as described above, the mount outer circumference of the eyepiece 4 and the mount outer circumference of the camera 11 side need to be adjusted. The adjustment is easy if a scale or the like that can be easily set to an appropriate angle is provided, or the click mechanism can always be set to an appropriate angle.

If the birefringent element 19 is detachably attached to the flexible endoscope 1 side, it is possible to observe an optical image without any displacement when observing with the naked eye. Even when the birefringent element 19 is attached, when the double image is considered to be troublesome, the ordinary ray and the extraordinary ray are polarized in the directions in which the respective vibrating surfaces are normally perpendicular to each other, and therefore the polarizing plate is used. If interposed, only one optical image can be observed. Also, the images that are slightly shifted are superimposed, but the image due to one (for example, an extraordinary ray) does not have to be a perfect image, and the image due to an extraordinary ray becomes an (incomplete) double image. Even in such a case, any image can be formed as long as a bright image is formed on the dark portion of the image formed correctly.

It should be noted that CCD (electrically coupled device), BBD are used as the above-mentioned photographing device.
(Bucket relay device), MOS image sensor, and the like can be similarly applied to a television camera in which a solid-state image pickup element formed by arranging minute light receiving elements having a photoelectric conversion function is arranged at an image forming position.

The present invention is a viewing device in which a fiber bundle image guide that can be attached to an eyepiece is formed instead of a photographing device such as a camera 11 attached to an eyepiece of an endoscope that uses a fiber bundle as an image guide. Is similarly installed (including not only medical endoscopes but also industrial endoscopes). In this case, for example, a known viewing device is attached to the endoscope eyepiece 4 instead of the camera 11 in FIG. 1, and the moire fringes are reduced as in the case of the camera.

[Effects of the Invention] As described above, according to the present invention, the influence of the fiber arrangement is substantially eliminated by using the optical filter formed of the birefringent plate. Therefore, it is possible to obtain an object image with good image quality, and in the case of viewing, it is possible to reduce the occurrence of moire fringes due to the interference of two image guides.

[Brief description of drawings]

1 to 3 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 view showing the vicinity of the exit end of an image guide to which a birefringent element is attached. FIGS. 3A and 3B are explanatory views showing optical images of the exit end of the fiber formed on the film surface of FIG. 1 ... flexible endoscope, 2 ... insertion part, 3 ... operating part, 4 ... eyepiece part, 6 ... tip part, 11 ... camera, 12 ... tube part, 13 ... camera body part, 14 ... … Lens, 15 …… Film 16 …… Viewfinder 18 …… Image guide, 18A …… Fiber 18B …… Exit end, 19 …… Birefringent element 20 …… Mounting bracket

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takeaki Nakamura 2-34-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (56) Reference JP-A-55-143125 (JP, A) Actual Kosho 47-18689 (JP, Y1)

Claims (8)

[Claims] 1. An objective lens, an image guide fiber bundle for receiving an object image formed by the objective lens on an incident end surface and transmitting the object image to an exit end side, and an image guide fiber bundle on the exit end side of the image guide fiber bundle. The image receiving means is formed by an image forming lens for forming the transmitted image and an image formed by the image forming lens, which is composed of a light sensitive section arranged behind a filter in which a plurality of regions of different colors are regularly arranged. An endoscope apparatus, comprising: an image pickup device for picking up an image of an object, and an optical filter formed of a birefringent plate provided in an optical path from the exit end face of the image guide fiber bundle to the image receiving means. . 2. An image of an exit end face of an image guide fiber bundle by an ordinary ray emitted from the birefringent plate and an image of an exit end face of an image guide fiber bundle by an extraordinary ray, one of which is the other image. The endoscope apparatus according to claim 1, wherein the thickness of the birefringent plate is selected so as to overlap the dark portion of the gap of the filter. 3. The endoscope apparatus according to claim 1, wherein the optical filter is detachably provided in the optical path. 4. The objective lens and the image guide fiber bundle are inside an endoscope, and the image receiving means is inside a camera attached to the endoscope. Endoscopic device. 5. The endoscope apparatus according to claim 1, wherein the optical filter is arranged inside the endoscope. 6. The endoscope apparatus according to claim 1, wherein the optical filter is provided in a camera. 7. The endoscope apparatus according to claim 1, wherein the image forming lens comprises an eyepiece lens of an endoscope and an image pickup lens provided behind the eyepiece lens. 8. An objective lens, an image guide fiber bundle for receiving an object image formed by the objective lens on an incident end surface and transmitting the object image to the exit end side, and an image guide fiber bundle on the exit end side of the image guide fiber bundle. An imaging lens for forming the transmitted image, and a second for receiving the image formed by the imaging lens
A viewing device having the image guide fiber bundle, and an optical filter formed of a birefringent plate provided in an optical path from the exit end face of the image guide fiber bundle to the second image guide fiber bundle. Endoscope device.