JPH10318727A - Inside-of-conduit diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inside-of-conduit diagnostic apparatus whose structure is simple, by which a defect on the inside wall of a long pipe is detected and in which a parachute is not projected inside a photographed image by a method wherein illumination light is supplied to a wall surface inside a conduit, reflected light from the whole circumference is received so as to be image-formed as an image without a gap the image is transmitted by an image transmission means. SOLUTION: An inside-of-conduit diagnostic apparatus is provided with a light-receiving means as a conical prism 63, and with an image formation lens 31 which forms an image at a bundle-type image fiber 36. It is constituted of an image fiber as a transmission means around it and of a bundle fiber 64 for illumination light. A parachute 52 is attached so as to be freely rotatable, and a force in an advance direction and a turning force are generated by a whirling flow inside a pipe. The image of a flaw or the like existing on a pipe wall is incident on the conical prism 63, it is totally reflected by an opposite slope, it is incident on the image formation lens 31 at the image fiber 64, and it is image-formed on the end face of the bundle-type image fiber 36 so as to be transmitted. A beam of light which is transmitted through the fiber 64 which is arranged in a multilayer concentric shape on the outer circumference of the image fiber 36 is reflected by the slope of the prism 63 equally to the incident light so as to irradiate an imaging range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a defect such as a crack in an inner wall of a pipe by an in-pipe diagnostic apparatus, and for example, to detect a defect in an inner wall of a long pipe only by passing an optical bundle fiber. The present invention relates to an in-pipe diagnostic device configured as described above.

[0002]

2. Description of the Related Art Conventionally, an in-pipe diagnostic apparatus for detecting a defect on an inner wall of a pipe uses an image fiber connected to a sensor means such as an endoscope in addition to an apparatus using ultrasonic waves. There is a diagnostic device to get. Here, a device using this image fiber will be particularly described.
As shown in FIGS. 1A and 1B, this conventional device is composed of a bundle type image fiber 4 for transmitting an image formed by bundling tens of thousands of optical fibers, and the obtained light is imaged on the bundle type image fiber 4. It is mainly composed of an imaging lens 1 to be made. Further, there is a type in which a large number of optical transmission fibers 2 for transmitting illumination light in a ring shape are arranged around the bundle type image fiber 4 when illumination light is required for observation or diagnosis. .

[0003] As shown in FIG. 10 (a), from the bundle type image fiber 4 as an ordinary in-pipe diagnostic device, the front can be observed at an angle of view determined by the characteristics unique to the imaging lens 1. In this case, the illuminating light is projected at an emission angle determined by the optical characteristics of the optical fiber 2, and the illuminating light spreads to obtain an image 5. FIG. 10B illustrates a so-called “side-view type” image fiber 4. When looking into a side surface such as a tube wall, an optical system for deflecting light is added in front of the above-described imaging lens 1 so that the image 5 can be "side-viewed" in a direction perpendicular to the longitudinal direction as shown in the figure. Some methods have made it possible. In such a "side view type", side view can be performed at an angle of view determined by the characteristics of the optical system, but the entire circumference of the inner wall of the tube cannot be seen. As described above, in any of the above-described methods, it was impossible to change the field of view by freely changing the tip of the bundle-type image fiber to a desired angle, and to observe the image.

Therefore, the method illustrated in FIG. 11 is one in which the above-mentioned drawbacks are solved, and the tip of the fiber is improved so that "swinging" can be performed by operating three to four wires. That is, the outer tube fixing flange 33 is fixed to the tip of the fiber 36, and the metal wire 35, which is formed by twisting a large number of 3 to 4 ultrafine wires of the same diameter at equal intervals, is attached. In addition, distal end flanges 32 having substantially the same diameter are provided at predetermined intervals. Fixed flange 33
, A spring-shaped outer tube 34 that is “closely wound” at the same interval and having the same diameter is fixed. This fixed flange 3
3, a hole through which the wire 35 freely passes without resistance penetrates through a portion to which the outer tube 34 is fixed. Also,
Wire 35 fixed to flange 32 at fiber tip
Penetrates to the outer tube 34. When the wire 35 is pulled in such a mechanism, the outer tube 34 does not shrink even when a compressive force is applied because it is "closely wound", and the distance between the distal end flange 32 and the outer tube fixing flange 33 is reduced. Therefore, since the contracted portion is bent, the operation with at least three wires 35
The direction in which the tip of the image fiber is directed can be freely changed to enable the "swinging" operation. However, although this method is excellent in function, it is inevitable to arrange an outer tube 34 having a metal wire 35 penetrating around the outer periphery of the image fiber, and its length is also limited. However, it was not suitable for diagnosing a long “long tube”.

Normally, in order to detect a defect in a long tube, the optical bundle fiber must be penetrated deep into the tube. In this case, for example, the optical fiber is passed through a system as shown in FIG. . That is, there has been an in-pipe diagnosis apparatus using a conventional and most effective method called a "spiral flow method". More specifically, this is a method of obtaining video information via a video transmission code 21 through a diagnostic video sensor 20 in a pipeline 71. For this reason, the sensor 20 passes through the conduit 71 from the inlet of the Coanda spiral unit 26 to the deep portion through the flexible hose 27 by compressed air for generating a spiral flow supplied by the compressed fluid supply means 25 such as a compressor or a cylinder. Diagnosis was performed while connecting. In this method, a parachute that has received a spiral flow pulls an optical bundle type image fiber forward and passes it through a conduit. At this time, the state of the inner wall of the conduit is changed to the tip flange 32 including the imaging lens 31.
The orientation can be changed by "swinging" the plurality of wires attached to the wire by an appropriate operation. However, in practice, twisting and loosening occur as the wire length increases, so that there is a tendency that not only skill is required for the mechanical control operation of the desired swing, but also it is difficult to perform the operation well.

In order to effectively pass the bundle type image fiber through the pipe by the spiral flow method, it is essential to attach a parachute to propel the tip of the fiber in the traveling direction.
In the case of the "swinging type" optical bundle fiber having the above-mentioned functions as shown in FIG. 5, the performance is excellent because the parachute 52 is attached to the front of the tip portion that can be swung. However, it is still unsuitable for the long tube as described above, and there is a problem that the front parachute itself is reflected in the center of the image in the front view.

[0007]

As described above, in a conventional diagnostic apparatus in which an image of an inner wall defect is projected and detected as an image by passing an image fiber through the inner wall of a long tube, the tip is bent and the head is swung. Although mechanical means was used, the mechanical components of the mechanical means increased the fiber diameter and caused an increase in weight, and this diagnosis was performed especially when the inner diameter of the pipe to be inspected was small. It is practically difficult to pass the sensor part of the apparatus, and the reliability of the diagnosis is often low, and a satisfactory pipe line diagnosis apparatus cannot be put to practical use. Furthermore, the problem that the parachute in the spiral flow method is reflected in the obtained image field of view has not been solved yet.

Accordingly, the present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a simple structure, which enables observation of the inner wall of the pipe over the entire circumference, and enables the state of the wall to be observed. Provided is an in-pipe diagnostic apparatus capable of detecting a defect in an inner wall of a long pipe while taking a picture, and performing a practical and effective in-pipe diagnosis so that a parachute attached to the tip is not reflected in a captured image. It is in.

[0009]

The present invention employs the following means in order to solve the above problems and achieve the object. For example, the present invention is a light receiving unit that optically acquires the reflected light from the entire circumference of the pipe inner wall, and an image forming unit that collects light from the light receiving unit and forms an image without a break,
An in-pipe diagnostic device comprising a main body composed of image transmission means for transmitting the image obtained by the imaging means and illumination light transmission means for supplying illumination light to the inner wall of the pipe via the light receiving means. I will provide a.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. (First Embodiment) FIG. 1 schematically shows an in-pipe diagnostic device of the present invention using an optical bundle fiber. This in-pipe diagnostic device includes a predetermined prism 63 as a light receiving unit for optically capturing images of the front and the surroundings,
An image forming lens 31 serving as image forming means for forming an image on the bundle type image fiber 36, and an image transmission system comprising a plurality of optical fibers bundled in the longitudinal direction around the image forming lens 31. It is mainly composed of a bundle type image fiber as a means, and an illumination light fiber as an illumination light transmitting means which is arranged in a ring shape around the image fiber and is necessary for diagnosis.

The bundle type image fiber and the illumination light fiber are bundled as shown in FIG.
A prism having a predetermined shape, for example, a conical prism 63, is fixedly joined to an end face of the mounting flange 65 at its tip. At this time, the axis passing through the vertex of the conical prism 63 passes through the center of the prism mounting flange 65 and is arranged in parallel with the longitudinal direction of the bundle fiber.
According to this arrangement, the center line of the fiber is optically matched with the vertex of the conical prism 63 as shown in FIGS. 4 (a) and 4 (b). As shown in (1), it is possible to display the entire 360 ° field of view as an image in which the tube wall is shifted by 180 ° (image rotated 180 °).
Note that the image rotated 180 ° becomes an actual image if the image is rotated 180 ° when projected on a monitor screen, and there is no problem in diagnosis.

A parachute connecting ring 61 is rotatably mounted on the apex of the prism mounting flange 65 via a U-shaped mounting arm 62 as shown in FIG. One parachute 52 is rotatably attached via the parachute attachment string 51. When the spiral flow (spiral flow) generated in the pipe is received, a force for pulling the entire bundle fiber in the traveling direction and a rotational force due to the spiral flow are generated in the parachute 52. However, this rotation force can be freely rotated without twisting by the rotation of the rotatable connection ring 61, and only the pulling force can be transmitted.

Further, the handle type image fiber 36
Since the fiber is weak in bending force and tension, a coating tube 66 is formed on the fiber as shown in FIG. 1 so as not to directly apply tension to the fiber. It is configured to handle the tube 66 directly.

(Operation and Effect 1) Here, the operation of the light receiving means will be described in more detail. FIG. 2 shows a state where the light receiving means is inserted into the tube and the tube wall 71 is observed. Now, light a from the flaw A on the tube wall enters the prism 63 from the slope of the conical prism 63, travels through the prism, and reaches the opposite slope of the prism. At this time, since the glass is dense with respect to the air (atmosphere), if the incident angle is equal to or greater than the critical angle, the light is totally reflected, and travels through the prism without leaking to the air side. Surface). Similarly, light a 'from the other end of the flaw A enters the conical prism 63 and totally reflects to reach the bottom of the prism, and the light emitted from the image A' is transmitted through the optical fiber imaging lens 31. Let them be tied together
Images are transmitted by the handle type image fiber 36.

Similarly, in FIG. 2, the same can be said for the scratch (A) and the scratch (B) at a position (lower surface) at 180 °.
That is, the light b from the scratch B ′ enters the conical prism 63 from the slope of the prism, travels through the prism,
The light reaches the opposite slope of the prism, travels through the prism after being totally reflected, and reaches the bottom surface of the prism. Similarly, the light b 'from the scratch B reaches the bottom surface of the prism after refraction and total reflection in the prism, and this image B' (however, it is not actually formed, ) Is formed through an optical fiber imaging lens 31, and the image is transmitted by a bundle type image fiber 36. Therefore, as described above, a similar relationship is established at any angle of the tube wall, and the omnidirectional (that is, 360 °) tube wall can be captured as an image, and the image can be transmitted far. it can.

Next, a relational expression between the viewing angle of the tube wall in this case and the apex angle of the conical prism 63 is obtained. FIG. 3 shows a more detailed optical analysis. Here, light from the tube wall flaw (A) is incident on the inclined surface of the prism at an incident angle i and a refraction angle r.
, And the refractive index N _ag (a: air, g: glass; this display is the refractive index when light travels from a to b) is obtained from the following relational expression. ). That is,

[0017]

(Equation 1)

Therefore, the light travels in the prism 63 at this angle. The light that has traveled is totally reflected on the other inclined surface of the conical prism 63. The relational expression at this time is as follows, assuming that the incident angle with respect to the air layer is r ′ and the angle refracted into the air layer is i ′, i ′ = 90 ° and the refractive index N _ag = _1.5 . Since r ′ = 41.8 according to equation (1), r ′>
If the incident angle is 41.8 or more, total reflection occurs. Now, assuming that the half angle of view of the fiber is θ _pf , the apex angle of the conical prism 63 is θ _p, and θ _h = (１ ／) θ _p , the entire relational expression is as follows.

[0019]

(Equation 2)

[0020]

(Equation 3)

It is understood from these equations that the tube wall can be observed at a desired angle by setting the apex angle of the conical prism 63. Therefore, if this prism is configured to be appropriately replaceable, observation at an optimum observation angle according to a non-inspection object is also possible.

As described above, in the embodiment of the present invention, the reflected light from the image (scratch, crack, etc.) existing on the tube wall is shown in FIG.
As shown in c), the light is refracted and enters the conical prism 63, is totally reflected on the inclined surface opposite to the incident side, and enters at an angle of view determined by the imaging lens of the imaging unit 3 of the bundle type image fiber 4. When the image is formed on the end face of the bundle type image fiber 36 by this imaging lens, this image is transmitted to the observer side by the subsequent fiber and used for diagnosis. On the other hand, the light beam for illumination emitted from the bundle optical fiber 2 transmitting the illumination light arranged in a multilayer concentric manner on the outer periphery of the bundle type image fiber 36 advances to the slope of the truncated cone prism 63, and the slope of this prism Is reflected at the same angle as the incident angle, and the path of the illumination light is bent, effectively illuminating the imaging range of the inner wall of the tube.

(Modification) In the above-described first embodiment, the conical prism 63 is used as an example of the prism. However, in addition to the conical prism, an isosceles prism 101 as shown in FIG. Equations (1) to (3) also hold for an equilateral polygonal pyramid prism having an even angle as shown in FIG. 5 (b), and therefore, the tube wall is observed at an arbitrary angle similarly to the conical prism 63. It becomes possible. However, in the case of an equilateral polygonal pyramid prism, it is necessary that the total reflection surface always exists relative to the incident surface, and the prism must be an even-numbered prism (for example, a hexagonal equilateral prism 104). The length of the coating tube 66 may be the entire length of the device, or may be a partial length up to the vicinity of the distal end.

(Function and Effect of Modification) As described above, not only the conical prism 63 is used as the light receiving means for the tube wall image, but also an isosceles prism or an equilateral polygonal pyramid prism (hexagonal equilateral prism) having an even angle is used as the light receiving means. The same effect can be obtained by adopting. Also, in this case, the same effect can be obtained if the illumination prism is formed in the same shape as when the conical prism is used as the light receiving means. In this case, the light receiving means is an isosceles or an equilateral polygonal pyramid prism having an even-numbered angle, and the illumination section is a combination such as a truncated cone prism, and the bottom surfaces of both prisms have an integral shape whose optical axes coincide with each other. , The diameter of the upper surface circle of the truncated cone matches the diameter of the image fiber.

(Second Embodiment) Next, a second embodiment of the present invention will be described. In the operation of the in-pipe diagnostic device of the present invention in the "spiral flow method", the spiral compressed air of the spiral flow is transmitted to the inside of the pipe, and the bundle-type image fiber is propelled forward while floating at the center of the pipe, and at the same time, parachute. The parachute can be propelled forward while rotating, and the parachute can be entirely advanced forward by pulling the bundle-type image fiber with a large force and can pass through the tube. The description of the second embodiment will be continued with reference to FIG. 1 again. In this embodiment, the bundle type image fiber 36
Although it is necessary to attach the parachute 52 to the distal end in order to insert the parachute into the tube, in order to achieve a further object of the present invention, as an improvement for solving the problem that the parachute 52 is reflected in the center of the plane image, The parachute 52 is arranged so as to enter a position corresponding to a "blind spot" area of an image by the adopted optical system. In other words, the layout characteristics of the second embodiment will be described with reference to FIG. 2. An area surrounded by double oblique lines (mesh) in FIG. 2 (however, this is a part that forms a three-dimensional conical shape) Numeral 72 designates a "blind spot" of the image formed by the prism 63, so that the parachute 52 as shown in FIG. 1 and the parachute attachment string 51 and the parachute connecting ring 61 as accessories of this parachute are arranged in this area. ing.

The parachute 52 and the parachute accessories (51, 61) are arranged in a blind spot area as shown in FIG. 2 (that is, a place where the area shown in the image is avoided). These images are not shown at all.

(Function and Effect 2) As described above, the mounting ring 6 rotatable via the mounting arm 62 at the end of the light receiving means.
1, the parachute 52 is attached to the attachment ring 61 via at least three attachment cords, and the parachute 52 is attached at a position where the angle of view of the conical prism 63 is removed (within the blind spot). When compressed air such as spiral flow is received, the optical bundle type image fiber is pulled forward to advance the pipeline. At this time, since it is attached within the blind spot of the conical prism 63, it is not reflected in the image range. That is, according to the arrangement of the parachute within the blind spot of the optical system as exemplified in the second embodiment, the image of the tube wall is not affected at all, and the parachute 52 does not appear as an image. Therefore, an image over the entire circumference of the pipe wall can be projected, and the entire area of the pipe wall sandwiched between the dotted lines in FIG. 2 can be captured as an image image, and thus sufficient in-pipe video can be supplied. Contributes to reliable diagnosis.

Third Embodiment Next, a third embodiment of the present invention will be described.
An embodiment will be described. First, referring to FIGS. 4 (a) and 4 (b), the joining relationship between the image forming portion of the optical fiber and the prism will be described. As shown in FIG. The bundle fiber 36 is structurally located on the center side, and the bundle fiber 2 for transmitting illumination light therearound and illuminating the object to be inspected surrounds the image fiber. Are located in FIG. 4 (c)
As shown in FIG. 4 (b), the reflected light from the image image is taken into the prism 63, and the illumination light for transmitting an image image of visible brightness as shown in FIG. Light enters the slope of the truncated cone. Since a predetermined reflecting substance is coated on the inclined surface of the prism 63 of the present embodiment, the illumination light is reflected here and is projected on the inspection object. At this time, the illuminating light is projected at an emission angle determined by the optical characteristics of the optical fiber employed, so the spread of the illuminating light is determined by the emission angle, and the light reflected by the inclined surface of the truncated cone of the prism is also used. Spreading around at an angle. The bending angle of this illumination light depends on the angle of the slope of the truncated cone, is naturally limited, and cannot be bent at any angle.
It can be seen that the illumination light can be bent at an arbitrary angle and projected by using a prism dedicated to the illumination light.

FIGS. 6 (a) and 6 (b) show an essential part of a third embodiment of the in-pipe diagnostic apparatus of the present invention in an exploded view and an assembled view, and FIG. The operation of the present embodiment is optically described with a plane cut at the center.
That is, as shown in FIG.
Is set in the shape of a truncated cone, and a hole is provided through the center of this prism so that the truncated cone 102 of the conical prism 63 for receiving light is fitted into the portion 112 without any gap as shown in the figure. Is formed. Then, in this fitted state, the bottom surface is the illumination light prism 11.
0, and is planarly bonded to the end face of the optical bundle fiber 36.

The outer diameter of the bottom circle of the light receiving conical prism 63 is equal to or larger than the outer diameter of the image fiber 36, and the outer diameter of the illumination light truncated conical prism 110 is equal to the illumination bundle fiber. The size is set to be larger than the outer diameter of the array circle and to be able to deflect the illumination light emitted from the optical fiber 2. Therefore, the illumination light emitted from the optical fiber 2 travels through the illumination light prism 110 at a predetermined emission angle, is totally reflected by the bottom surface 112, travels to the prism outer peripheral surface 111, is refracted, and is emitted into the air. .

Referring to FIG. 7, optical details will be described. The light beam from the illumination light fiber has a truncated conical prism 1 at an emission angle θ _opf determined by the optical characteristics of the fiber.
When the light enters the surface 10, the light is totally reflected by the slope e1 and finally travels to the air layer to become light illuminating the tube wall. For example, the light beam from the optical fiber a is totally reflected on the slope e1 as shown by the broken line, travels from f1 to the air layer, and illuminates the tube wall as a1,
Further, as shown by one solid line, the light is totally reflected on the slope e2, refracted from f2, travels to the air layer as a2, and illuminates the tube wall. Similarly, the light rays from the optical fiber b eventually travel to the air layer as b1 and b2 and illuminate the tube wall. As described above, the optical fibers a located at the outermost circle w2 and the optical fibers b located at the innermost circle w1 of the bundled bundle of fibers for illumination 2 as shown in FIG.
The tube wall can be illuminated by the spread of the angle θ _ab formed with 2.

The above relationship is shown in the optical fiber c shown in FIG.
From the optical fiber c, θ
_When the illumination light is emitted at the output angle of the _opf , totally reflected at e5, refracted at the f1 point based on the above equation (1), and exits to the air layer to become the light ray c2, it is expressed as follows. Here, the outgoing angle of the fiber is θ _opf , the inclination angle of the bottom surface of the truncated cone is θ _h , the inclination angle of the outer peripheral surface is θ _oh , and the refractive index is N _ag (a: air, g: glass; (Indicating the index of refraction of light as it travels from a to b)
_o2 is represented by the following equation.

[0033]

(Equation 4) On the other hand, the angle θ _{o1 of the} light ray c1 is represented by the following equation.

[0034]

(Equation 5)

As can be seen from the equations (4) and (5), the direction in which the tube wall is desired to be illuminated by appropriately setting the inclination angle θ _oh and the inclination angle θ _h of the outer peripheral surface of the truncated cone prism. Can be freely changed.

(Effect 3) When the dedicated illumination light prism is used as exemplified in the third embodiment, the illumination light emitted from the bundle fiber is conical with the illumination light prism. After being totally reflected at the bottom surface of the pedestal hole and refracted at the outer peripheral surface, it can be bent to illuminate the tube wall effectively. In addition, by coating a substance that reflects on the entire slope of the truncated cone of the prism so that the illumination light does not travel inside the prism, the image light and the illumination light are completely separated, so the illumination light has an adverse effect on the image light This provides an accurate image without giving an image, thereby contributing to a highly reliable diagnosis. Furthermore, if a ring-shaped illumination light prism having a truncated conical hole into which the truncated cone portion of the conical prism for light reception fits is used at the center, the deflection angle can be set more freely.

(Other Modified Embodiments) For example, in order to positively spread the illuminating light over a wider range of the wall surface, it can be easily achieved by forming the outer peripheral surface of the prism into, for example, a concave shape. That is, if the illumination light truncated cone 130 having the shape shown in FIG. 8 is used, the illumination light can be distributed over a wider range.

An appropriate combination of the above embodiments is also possible. In other words, according to the improvement of the arrangement of the parachute as described above, the combination of the plurality of prisms, and the coating on the predetermined prism surface, the image light and the illumination light can be completely separated, and the illumination light passes through the main prism. Without any influence on the image light, it is possible to efficiently illuminate brightly without any influence on the image light, and furthermore, it is possible to eliminate an image such as a parachute unnecessary for the diagnosis itself from the obtained image, so that it is synergistic. It is possible to provide an in-pipe diagnostic device which can contribute to highly reliable and accurate diagnosis. Various modifications can be made without departing from the spirit of the present invention.

[0039]

The effects of the present invention can be summarized as follows. That is, (1) the light bundle type image fiber and the light receiving means consisting of, for example, a conical prism attached to the tip thereof,
It is possible to inspect the inner wall of the pipeline over the entire circumference without performing any conventional mechanical motion operation.
The effect that the parachute indispensable for the "spiral flow method" does not appear on the image screen is also obtained.

As with the conical prism, it is possible to observe the tube wall at an arbitrary set angle using not only a conical prism but also an isosceles prism or an equilateral polygonal prism having an even angle. (2) Coating a reflective material on the slope of the truncated cone prism, and reflecting and bending the illumination light on this slope,
The image light and the illumination light can be completely separated, so that the adverse effect of the illumination light on the image light can be completely prevented. (3) If the illumination light truncated cone is used, the illumination light can be further bent to an arbitrary angle, and the tube wall portion to be illuminated can be effectively illuminated. (4) By making the outer peripheral surface of the illumination light prism concave, a wider spread angle of the illumination light can be set. (5) Since the structure does not apply mechanical stress such as bending and torsion, accidents such as breakage of an optical fiber which is particularly vulnerable to bending can be fundamentally improved. (6) Due to the structure having no mechanically movable parts, as long as the factors determined by the optical characteristics of the fiber are satisfied, the structure can be applied to any length or diameter tube, and the field of application is widened.

As described above, according to the present invention, the inner wall inside the tube can be easily viewed over the entire circumference, while having a simple optical structure without using any mechanical means. An extremely practical and effective in-pipe diagnosis that can easily detect defects on the inner wall and does not appear in the captured image even though the parachute is attached to the tip. An internal diagnostic device can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an in-pipe diagnostic device using an optical bundle fiber according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram for describing optical analysis and operation of the in-pipe diagnostic device of the present invention.

FIG. 3 is an explanatory diagram for explaining a more detailed optical analysis of FIG. 2 and an operation thereof.

4A and 4B show main parts of the in-pipe diagnostic apparatus of the present invention, wherein FIG. 4A is a front view as seen from the prism, and FIG.
Is a side view of the prism, the imaging unit, and the bundle-type image fiber, (c) is a longitudinal sectional view for explaining optical analysis of the prism in the pipe, and (d) is an image of the obtained pipe inner wall. Explanatory drawing showing an image.

FIG. 5 shows two examples of a prism according to the present invention,
(A) is a perspective view showing an isosceles prism, and (b) is a perspective view showing an even-angled isosceles polygonal prism.

FIG. 6 shows an example of the in-pipe diagnostic device of the present invention;
(A) is an exploded view, and (b) is an assembled view.

FIG. 7 is an explanatory diagram showing an optical analysis relating to the illumination light prism according to the present invention.

FIG. 8 is an assembly view of the in-pipe diagnostic device including the concave illumination light prism according to the present invention.

FIG. 9 shows a conventional image fiber cable;
(A) is a sectional view of an imaging lens and a fiber in the cable, and (b) is a side view of an imaging part and a bundle type image fiber.

10A and 10B show an image formed by a conventional image fiber. FIG. 10A is a side view of a bundle-type image fiber having a normal image forming portion, and FIG. 10B is a diagram having a “side-view” image forming portion. The side view of a bundle type image fiber.

FIG. 11 is a schematic view of a conventional swingable image fiber.

FIG. 12 is a schematic diagram showing a conventional in-pipe diagnostic apparatus using a spiral flow method and its operating environment.

FIG. 13 is a schematic diagram of an in-pipe diagnostic device using an optical bundle fiber adapted to a conventional spiral flow method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Image forming lens, 2 ... Illumination light transmission fiber, 3 ... Image forming part (image forming lens system), 4 ... Bundle type image fiber, 31 ... Image forming lens, 36 ... Bundle type image fiber, 51 ... Parachute attachment string 52, parachute, 61, parachute mounting ring, 62, mounting arm, 63, conical prism, 64, bundle fiber (for lighting), 65, prism mounting flange, 66, covering tube, 67, tube mounting ring, 71, tube (Inner wall), 72: Blind spot of image, 73: Image range, 91: Center of image fiber, 92: Center of conical prism, 93: Position of flaw, 93 ': Screen (field of view), 94: In-tube (image image) ), 101: isosceles prism, 102: truncated cone prism, 103: joint surface of optical bundle fiber, 104 ... hexagonal equilateral prism, 110 ... truncated cone illumination light prism, 111 ... outer peripheral surface of illumination light prism, 112 ... bottom surface of illumination light prism, 115 ... unit after assembling, 130 ... outer peripheral concave surface of frustoconical illumination light prism.

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[Procedure amendment]

[Submission date] July 24, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0002

[Correction method] Change

[Correction contents]

[0002]

Conventionally, the conduit diagnostic device for detecting a defect in the pipe inner wall in addition to the device you use an ultrasound image image using image fiber subsequent to the sensor means, such as an endoscope There is a diagnostic device for obtaining Here, a device using this image fiber will be particularly described.
As shown in FIGS. 1A and 1B, this conventional device is composed of a bundle type image fiber 4 for transmitting an image formed by bundling tens of thousands of optical fibers, and the obtained light is imaged on the bundle type image fiber 4. It is mainly composed of an imaging lens 1 to be made. Further, there is a type in which a large number of optical transmission fibers 2 for transmitting illumination light in a ring shape are arranged around the bundle type image fiber 4 when illumination light is required for observation or diagnosis. .

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

The bundle type image fiber and the illumination light fiber are bundled as shown in FIG.
As, be fixed to the prism mounting flange 65 at the distal end, the prism forming a predetermined shape, for example conical prism 63 is bonded fixed is <br/> the end face of the mounting flange 65. At this time, the axis passing through the vertex of the conical prism 63 passes through the center of the prism mounting flange 65 and is arranged in parallel with the longitudinal direction of the bundle fiber. According to this arrangement, the center line of the fiber is optically matched with the vertex of the conical prism 63 as shown in FIGS. 4 (a) and 4 (b). Image in which the tube wall is displaced by 180 ° as shown in (image rotated by 180 °)
As a result, it is possible to project a full 360 ° field of view. Note that the image rotated 180 ° becomes an actual image if the image is rotated 180 ° when projected on a monitor screen, and there is no problem in diagnosis.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

Next, a relational expression between the angle at which the tube wall is viewed and the apex angle of the conical prism 63 is determined. FIG. 3 shows a more detailed optical analysis. Here, light from the tube wall flaw (A) is incident on the inclined surface of the prism at an incident angle i and a refraction angle r.
, And the refractive index N _ag (a: air, g: glass; this display is the refractive index when light travels from a to b) is obtained from the following relational expression. ). That is,

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction contents]

Referring to FIG. 7, optical details will be described. The light beam from the illumination light fiber has a truncated conical prism 1 at an emission angle θ _opf determined by the optical characteristics of the fiber.
When the light enters the surface 10, the light is totally reflected by the slope e1 and finally travels to the air layer to become light illuminating the tube wall. For example, the light beam from the optical fiber a is totally reflected on the slope e1 as shown by the broken line, travels from f1 to the air layer, and illuminates the tube wall as a1,
Further, as shown by one solid line, the light is totally reflected on the slope e2, refracted from f2, travels to the air layer as a2, and illuminates the tube wall. Similarly, the light rays from the optical fiber b eventually travel to the air layer as b1 and b2 and illuminate the tube wall. Thus, the optical fibers a and located on the outermost yen w2 bundle illumination fiber 2 consisting of a number, the optical fiber b located at the outermost inner contour yen w1, as shown rays b1 and a
The tube wall can be illuminated by the spread of the angle θ _ab formed with 2 .

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction contents]

[0033]

(Equation 4) On the other hand, the angle θ _{o1 of the} light ray c1 is represented by the following equation.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] Fig. 8

[Correction method] Change

[Correction contents]

FIG. 8 is an exploded view of the in-pipe diagnostic device including the concave illumination light prism according to the present invention.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] Fig. 9

[Correction method] Change

[Correction contents]

FIG. 9 shows a conventional image fiber cable;
(A) is a front view of the imaging lens and the fiber, (b), the
FIG. 3 is a side view of the image forming unit and the bundle type image fiber.

[Procedure amendment 8]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

[Procedure amendment 9]

[Document name to be amended] Drawing

[Correction target item name] Fig. 7

[Correction method] Change

[Correction contents]

FIG. 7

 ──────────────────────────────────────────────────続 き Continuation of front page (71) Applicant 591211478 Ishihara Sangyo Co., Ltd. 1-3-3 Ote, Ueda City, Nagano Prefecture (72) Inventor Shigeyuki Tsurumi 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Co., Ltd. (72) Inventor Yoshikazu Ishii 1-3-1 Gotenyama, Musashino City, Tokyo NTT Advanced Technology Corporation (72) Inventor Kiyoyuki Horii Kamimeguro, Meguro-ku, Tokyo No.8-15-501 (72) Inventor Takehiko Sakaguchi 1-3-3 Otemachi, Ueda-shi, Nagano Pref. Ishihara Sangyo Co., Ltd.

Claims (9)

[Claims] 1. An in-pipe diagnostic apparatus for performing a diagnosis by inserting a device body into a pipe, a light receiving means for optically acquiring reflected light from the entire circumference of an inner wall of the pipe, and a light from the light receiving means. Imaging means for collecting and forming an image into a continuous image; image transmission means for transmitting the image obtained by the imaging means; and supplying illumination light to the inner wall of the pipe via the light receiving means. And an illumination light transmitting means. 2. The apparatus according to claim 1, wherein the light receiving unit is a prism having an optically predetermined shape. 3. The illumination light transmitting means is an optical fiber cable arranged so as to irradiate a predetermined surface of the light receiving means with illumination light, and the image transmitting means is obtained from inside the light receiving means. The in-pipe diagnostic device according to claim 1, wherein the device is an optical bundle type image fiber cable arranged so as to be able to transmit a video image. 4. The in-pipe diagnostic device according to claim 2, wherein the prism is a conical prism, an isosceles prism, or an equilateral polygonal pyramid prism having an even angle. 5. The prism is a combination of a conical prism as a light receiving prism for observing the inner wall of the tube and a truncated conical prism as an illumination light prism for reflecting illumination light and illuminating the inner wall of the tube. The truncated cone prism has an integral shape whose bottom surfaces are coincident with each other, and the diameter of the top circle of the truncated cone substantially matches the diameter of the image fiber as the image transmission means, and the slope of the truncated cone. 3. The in-pipe diagnostic device according to claim 2, wherein the whole is coated with a predetermined substance so as to reflect the illumination light and prevent the illumination light from propagating into the prism. 6. The in-pipe diagnostic device according to claim 5, wherein the truncated conical prism portion is selectively applicable instead of an isosceles prism or an even-numbered equilateral polygonal pyramid prism. 7. A truncated conical prism portion serving as the illumination light prism, a hole through which the frustoconical portion serving as the light receiving prism fits without a gap penetrates the center of the optical axis, and an outer periphery of the illumination light prism 6. The in-pipe diagnosis according to claim 5, wherein the ring has a predetermined inclined surface or a concave surface, and is configured to optically separate image light and illumination light. apparatus. 8. An apparatus for diagnosing the inner wall of a pipeline by inserting an omnidirectional side-viewing imaging light bundle fiber as an endoscope into the pipeline by a spiral flow method, wherein an optical blind spot of the light receiving prism is provided. The in-pipe diagnostic device according to claim 1, wherein a parachute as a propulsion force receiving means is further rotatably mounted in the region. 9. An in-pipe diagnostic apparatus for performing a diagnosis by inserting an apparatus body into a pipe, comprising: a bundle-type image optical fiber formed by bundling a plurality of optical fibers; An illumination optical fiber for transmitting the arranged illumination light, an imaging unit having an optical lens for forming an image on the tip of the bundle-type image optical fiber, and coaxially joined to the optical axis of the imaging unit An in-pipe diagnostic device comprising: a light receiving unit having a conical prism formed as described above; and a propulsion force receiving unit disposed in an optical blind area of the light receiving unit.