JP2016202192A - Rigid endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rigid endoscope of a simple and inexpensive configuration whose internal structure is not damaged when an insertion part is bent even if the insertion part is extra fine.SOLUTION: An objective element 43 is provided at the tip of an insertion part 20 that extends from a proximal part of a rigid endoscope 2, and an image formation element 45 is provided to the proximal part. An image light transmission medium consisting of one of gas, liquid, and light-transmitting resin is provided inside a cylindrical image light transmission member 44 connecting the objective element 43 and the image formation element 45. An illumination light transmission medium consisting of one of gas, liquid, and light-transmitting resin is provided between a cylindrical inner side reflection surface 34b surrounding an inner tube 22 and a cylindrical outer side reflection surface 34a surrounding it.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rigid endoscope, and more particularly to a rigid endoscope suitable for making an insertion portion extremely thin.

  Generally, in a rigid endoscope, an insertion portion extends linearly from a hand portion. An illumination optical system that transmits illumination light from the light source in the distal direction and an image optical system that transmits image light in the proximal direction are provided inside the insertion portion. Usually, the illumination optical system is composed of an optical fiber. The image optical system includes a relay lens including a rod lens and an optical fiber (see Patent Documents 1 and 2).

JP 2005-237436 A JP 2007-133175 A

For example, in a rigid endoscope for ophthalmology or the like, there is a demand for making the insertion portion as thin as possible. However, if the insertion portion is extremely thin, the internal relay lens is easily damaged even if it is slightly bent. In addition, when an optical fiber is provided in the insertion portion, if the insertion portion is narrowed, the number and thickness of the optical fibers are limited, so that the illumination becomes dark and the image quality deteriorates. Furthermore, relay lenses and optical fibers are relatively expensive.
SUMMARY OF THE INVENTION In view of the above circumstances, the present invention has an object to provide a simple and inexpensive configuration in a rigid endoscope, in which, when the insertion portion is thinned, the internal structure is not damaged even if the insertion portion is slightly bent. And

In order to solve the above-described problems, the present invention provides a hand portion, an insertion portion extending linearly from the hand portion along the axis, an illumination optical system that transmits illumination light from a light source to the observation target, and the observation target. A rigid endoscope provided with an image optical system that transmits the image light of the image sensor, wherein the image optical system includes an objective element provided at a distal end of the insertion portion and an imaging element provided at the hand portion And a cylindrical low reflection surface extending along the axis so as to communicate the objective element and the imaging element, and inside the low reflection surface, gas, liquid, translucent An image light transmission medium made of any of resins is provided,
The illumination optical system includes a cylindrical inner reflection surface extending along the axis so as to surround the low reflection surface, and a cylindrical outer reflection surface extending along the axis so as to surround the inner reflection surface, An illumination light transmission medium made of any one of gas, liquid, and translucent resin is provided between the inner reflection surface and the outer reflection surface.

  According to this characteristic configuration, since the structures of the illumination optical system and the image optical system are simple, the rigid endoscope can be made inexpensive. Since there is no need to provide an optical glass element other than the objective element, such as a relay lens for image light transmission, in the insertion part, even if the insertion part is made thin, the insertion part is bent under some bending load The optical glass element can be prevented from being damaged. In addition, since the objective element is provided in the front-end | tip part of an insertion part, even if the intermediate part of an insertion part is curved, there is almost no possibility of damaging. Further, since the imaging element is provided at the hand portion, there is no possibility of being damaged even if the insertion portion is bent. Furthermore, the illumination light is reflected by the outer reflection surface and the inner reflection surface, whereby the transmission efficiency of the illumination light can be increased, and the observation target can be reliably illuminated. Further, by suppressing the scattering of the image light on the low reflection surface, it is possible to prevent the image to be observed from becoming unclear.

The insertion portion includes a metal outer tube extending along the axis, and a metal inner tube housed in the outer tube and extending along the axis, and the outer tube and the inner tube It is preferable that the illumination light transmission medium is accommodated in between and the image light transmission medium is accommodated in the inner tube.
As a result, the internal structure of the insertion portion can be surely simplified, and the rigid endoscope can be made more inexpensive. The illumination light transmission path and the image light transmission path can be reliably partitioned by the inner tube. Moreover, it is possible to prevent the illumination light from entering the image light transmission path, and to ensure the sharpness (contrast) of the observation image. The outer tube and the inner tube are preferably made of metal. As a result, even if the insertion portion is slightly bent by the bending load, if the bending load is within the elastic deformation region of the outer tube and the inner tube, the elastic restoring force of the outer tube and the inner tube is released when the bending load is released. Thus, the insertion portion can be returned to the original linear shape. Therefore, illumination light and image light can be reliably transmitted.

The inner surface of the outer tube constitutes the outer reflecting surface, the outer surface of the inner tube constitutes the inner reflecting surface, and an annular cavity is formed between the outer tube and the inner tube. Gas or liquid may be accommodated as the illumination light transmission medium.
Thereby, the illumination light transmission structure in the insertion portion can be surely simplified, and the rigid endoscope can be reliably made inexpensive. Even if the insertion portion is bent, the illumination light transmission medium inside is a gas or a liquid, so that the illumination light transmission medium is not damaged. Air, nitrogen, etc. are mentioned as gas which comprises an illumination light transmission medium, Preferably it is air. Water is preferable as the liquid constituting the illumination light transmission medium. The liquid includes a sol body and a gel body.

An inner surface of the inner tube may constitute the low reflection surface, and an inner portion of the inner tube may be a cavity, and a gas or a liquid may be accommodated in the cavity as the image light transmission medium.
As a result, the image light transmission structure in the insertion portion can be reliably simplified, and the rigid endoscope can be reliably made inexpensive. Even if the insertion portion is bent, the internal image light transmission medium is a gas or a liquid, so that the image light transmission medium is not damaged. Examples of the gas constituting the image light transmission medium include air and nitrogen, and preferably air. Water is preferable as the liquid constituting the image light transmission medium. The liquid includes a sol body and a gel body.

  The illumination optical system includes a transparent cylindrical member made of a translucent resin having a central hole and extending along the axis, and an outer peripheral surface of the transparent cylindrical member constitutes the outer reflective surface, and the central hole The inner peripheral surface may constitute the inner reflection surface, and the image optical system may penetrate the center hole. By using the transparent cylindrical member as an illumination light transmission medium, it is possible to reliably reduce illumination light transmission loss. Moreover, by giving elasticity to the transparent cylindrical member, it is possible to prevent the illumination light transmission medium in the insertion portion from being damaged even if the insertion portion is bent slightly.

  The image optical system may include a transparent cylindrical member made of a translucent resin extending along the axis, and an outer peripheral surface of the front transparent cylindrical member may constitute the low reflection surface. By using the transparent cylindrical member as an image light transmission medium, it is possible to reliably transmit image light. Further, by giving elasticity to the transparent cylindrical member, it is possible to prevent the image light transmission medium in the insertion portion from being damaged even if the insertion portion is slightly bent.

The reflectance of the inner reflective surface and the outer reflective surface with respect to the illumination light is higher than the reflectance of the low reflective surface with respect to the image light, and the absorptivity of the inner reflective surface and the outer reflective surface with respect to the illumination light is as follows: The absorptivity of the low reflection surface with respect to the image light is preferably lower. Thereby, the transmission efficiency of illumination light can be reliably ensured and the observation image can be reliably prevented from becoming unclear.
The outer reflecting surface is preferably a mirror surface. The inner reflection surface is preferably a mirror surface. Thereby, the transmission efficiency of illumination light can be ensured reliably.
The low reflection surface is preferably a dark color surface. Thereby, scattering of image light can be reliably prevented.
The outer reflection surface and the inner reflection surface are preferably concentric cylinders. The outer reflective surface, the inner reflective surface, and the low reflective surface are preferably concentric cylinders.

  According to the present invention, the internal structure of the insertion portion can be simplified, and the rigid endoscope can be made inexpensive. Further, when the insertion portion is made thin, even if the insertion portion is bent slightly, the internal optical element can be prevented from being damaged. Furthermore, the illumination light transmission efficiency can be ensured and the clearness of the observation image can be ensured.

Fig.1 (a) is a longitudinal cross-sectional view which shows the rigid endoscope which concerns on 1st Embodiment of this invention in the state in which the insertion part and the hand part were connected. FIG. 1B is a longitudinal sectional view showing the rigid endoscope in a state where the insertion portion and the hand portion are separated. It is sectional drawing which abbreviate | omitted the internal structure of the said rigid endoscope which follows II-II of Fig.1 (a). It is a longitudinal cross-sectional view which expands and shows a part of said rigid endoscope. It is a perspective view of the light guide member of the said rigid endoscope. It is a block diagram of the endoscope apparatus containing the said rigid endoscope. It is a longitudinal cross-sectional view of a part of a rigid endoscope according to a second embodiment of the present invention. It is a longitudinal cross-sectional view of a part of a rigid endoscope according to a third embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 5, the endoscope apparatus 1 includes a rigid endoscope 2, a camera control unit (CCU) 3, and a monitor 4. The rigid endoscope 2 is, for example, an ophthalmic endoscope, but the present invention is not limited to this. As shown in FIG. 1A, the rigid endoscope 2 includes a hand portion 10, an insertion portion 20, an illumination unit 30, and an observation unit 40. The insertion portion 20 is connected to the distal end of the hand portion 10 (left side in FIG. 1A). Illumination means 30 and observation means 40 are provided inside the hand portion 10 and the insertion portion 20. The hand portion 10 is held by an operator, and the insertion portion 20 is inserted into an observation target such as an eye socket or lacrimal gland of a human body. The observation object around the distal end of the insertion portion 20 is illuminated by the illumination means 30. The image light to be observed is taken into the endoscope 2 by the observation means 40 and displayed on the monitor 4 through image processing by the CCU 3.

The structure of the endoscope 2 will be further described in detail.
As shown in FIG. 1A and FIG. 1B, the hand portion 10 and the insertion portion 20 are constituted by separate members and are separable (detachable). The hand portion 10 includes an outer casing 11, an inner casing 12, a sleeve 13, and a shaft tube 14, and has a multiple cylindrical shape extending along the axis L. As shown in FIG. 2, the cross-sectional shape of the hand portion 10 is a deformed ellipse shape similar to an oval shape. As shown in FIG. 1A, an inner casing 12 is accommodated in the outer casing 11, and a shaft tube 14 is accommodated in the inner casing 12 via a sleeve 13. The sleeve 13 and the shaft tube 14 are integrated with each other and are slidable in the axial direction (direction along the axis L) with respect to the outer casing 11 and the inner casing 12. Alternatively, the inner collar 12, the sleeve 13, and the shaft tube 14 may be integrated with each other and slidable in the axial direction with respect to the outer casing 11.

  As shown in FIG. 1, the insertion portion 20 extends linearly along the axis L from the distal end of the hand portion 10. As shown in FIG. 3, the insertion portion 20 includes an outer tube 21 and an inner tube 22 and has a double circular tube shape. The material of the outer tube 21 is preferably a metal having elasticity, such as stainless steel, ordinary steel, iron, aluminum or the like. The outer tube 21 and thus the insertion portion 20 are extremely thin. The outer diameter of the outer tube 21 is several mm (2 mm to 3 mm) or less, preferably 1 mm or less, for example, about 0.9 mm, but the present invention is not limited to this.

  The inner tube 22 has a smaller diameter than the outer tube 21 and is accommodated inside the outer tube 21 so as to be concentric with the outer tube 21. The material of the inner tube 22 is preferably a metal having elasticity, such as stainless steel, ordinary steel, iron, and aluminum. As shown in FIG. 1B, the base end portion (right end portion in the figure) of the inner tube 22 protrudes toward the hand portion 10 from the outer tube 21. A connecting pipe 23 is provided at the base end of the inner pipe 22.

  As shown in FIG. 3, the connecting tube 23 is composed of a small-diameter tube portion 23 a on the distal end side (left in FIG. 3), a central tapered portion 23 b, and a large-diameter tube portion on the proximal end side (right in FIG. 3). 23c integrally. The inner tube 22 and the connecting tube 23 are integrally connected by fitting the tube portion 23 a into the outer periphery of the proximal end portion of the inner tube 22. A tapered portion 23b is integrally connected to the proximal end portion of the tube portion 23a. The diameter of the taper portion 23b is increased toward the proximal direction. The pipe portion 23c is integrally connected to the enlarged diameter end portion of the taper portion 23b. The shaft tube 14 of the hand portion 10 is fitted into the tube portion 23c so as to be slidable and detachable in the axial direction. Accordingly, the proximal end of the inner tube 22 is connected to the shaft tube 14 along the axis L via the connecting tube 23 so that the relative position can be adjusted and the separation is possible.

  As shown in FIG. 1A and FIG. 1B, a connection member 50 is provided between the hand portion 10 and the insertion portion 20. The connecting member 50 is made of rubber (elastic material) and has elasticity. As shown in FIGS. 1B and 2, the connection member 50 integrally includes a covering cylinder portion 51 and a cap portion 52. The covering cylinder portion 51 is formed in a cylinder shape with the cylinder axis along the axis L, and the cross-sectional shape thereof is a deformed elliptical shape that is substantially similar to the hand portion 10. The base end part (the right end part in FIG.1 (b)) of the covering cylinder part 51 is opened. The tip end portion (left end portion in FIG. 1B) of the covering cylinder portion 51 is closed by the cap portion 52.

  As shown in FIG. 1B, the cap portion 52 has a conical wall shape that protrudes along the axis L in the distal direction (left in FIG. 1B). As shown in FIG. 3, the cap 52 has a conical recess 52 a and an insertion hole 52 b formed along the axis L. The conical recess 52a has a conical shape with a diameter reduced toward the tip (left in FIG. 3). The base end on the large diameter side of the conical recess 52 a is opened to the internal space of the covering cylinder portion 51. An insertion hole 52b is connected to the tip on the small diameter side of the conical recess 52a. The insertion hole 52b has the same diameter as the tip portion of the conical recess 52a and reaches the tip surface of the connection member 50.

  As shown in FIG. 1A, the connection member 50 covers the outer periphery of the proximal portion 10 and the insertion portion 20 so as to straddle between the distal end portion of the proximal portion 10 and the proximal end portion of the insertion portion 20. Yes. And the covering cylinder part 51 elastically adheres to the outer peripheral surface of the hand part 10 (one member), and the cap part 52 is joined integrally with the insertion part 20 (the other member). As a result, the hand portion 10 and the insertion portion 20 are detachably connected by the connection member 50.

The connection structure will be further described in detail.
The base end portion of the outer tube 21 is fitted into the insertion hole 52b. In the insertion hole 52b, the outer tube 21 and the cap portion 52 are integrally joined by an adhesive or the like. The protruding length of the outer tube 21 from the cap portion 52 is, for example, about 30 mm to 50 mm, but the present invention is not limited to this. The proximal end portion of the inner tube 22 protrudes from the outer tube 21 and penetrates the conical recess 52 a along the axis L, and is disposed inside the connection member 50.

The dimension of the inner peripheral surface of the covering cylinder part 51 in a natural state (no load) is slightly smaller than the dimension of the outer peripheral surface of the front end part of the outer casing 11. As shown in FIG. 1A and FIG. 2, the covering cylinder portion 51 covers the outer peripheral portion of the distal end portion of the outer casing 11, thereby being elastically adhered to the outer casing 11. The coated cylinder part 51 and the hand part 10 are detachably connected by this elastic force. In addition, a space between the inner peripheral surface of the covering cylinder portion 51 and the outer peripheral surface of the outer casing 11 is sealed in a liquid-tight manner.
In this connected state, the cap 52 is separated from the proximal portion 10 in the distal direction (left in FIG. 1A) and covers the distal end surface of the proximal portion 10.

  As shown in FIG. 2, a plurality (two in this case) of guide ridges 11 f are formed on the outer peripheral surface of the outer casing 11. These guide ridges 11f extend straight along the axis L and are spaced apart from each other in the circumferential direction. On the other hand, on the inner peripheral surface of the covering cylinder portion 51, a number (here, two) of guide grooves 51f corresponding to the guide protrusions 11f are formed. The guide grooves 51f extend straight along the axis L, and are spaced apart from each other in the circumferential direction, and are disposed at positions corresponding to the guide protrusions 11f. Each guide ridge 11f is slidably fitted along the axis L in the corresponding guide groove 51f. Thereby, the guide member 50 is prevented from rotating so as not to rotate relative to the circumferential direction of the hand portion 10.

  Further, as shown in FIG. 1, a locking recess 11 e is formed on the outer peripheral surface of the outer casing 11 in an annular shape along the circumferential direction of the outer casing 11. On the other hand, a locking projection 51 e that protrudes inward in the radial direction is provided annularly along the circumferential direction of the covering cylinder 51 at the base end of the covering cylinder 51. The locking projection 51e is fitted and locked in the locking recess 11e. Thereby, the outer casing 11 and the connection member 50 are positioned in the axial direction.

A position adjusting means 60 is provided between the connecting member 50 and the hand portion 10. The position adjusting means 60 includes a pinion 61 (circular gear) and a rack 62 (linear gear). The pinion 61 is rotatably embedded in the connection member 50. The connection member 50 is elastically in contact with the pinion 61, so that the space between the connection member 50 and the pinion 61 is liquid-tightly sealed. The rack 62 is fixed to the holder 14 of the hand portion 10. The pinion 61 and the rack 62 are engaged with each other. By rotating the pinion 61, the axial relative positions of the connecting member 50, the sleeve 13, and the shaft tube 14 can be adjusted. At the time of this position adjustment, the relative position between the connecting member 50 and the outer casing 11 is fixed.
Further, the engagement between the pinion 61 and the rack 62 can be released by elastically deforming the connecting member 50.

  As shown in FIG. 1A, the observation unit 40 includes an image optical system 41 and an image sensor 42. The image optical system 41 includes an objective lens 43 (object element), an image light transmission tube 44 (image light transmission member), and an imaging lens 45 (imaging element). The objective lens 43 is provided at the distal end of the inner tube 22 (that is, the distal end of the insertion portion 20).

  The image light transmission tube 44 includes the inner tube 22, the connecting tube 23, and the shaft tube 14, and extends in a straight line along the axis L. As shown in FIG. 3, the internal space of the image light transmission tube 44 is an image light transmission path 44d. The peripheral surface of the image light transmission path 44d (the inner surfaces of the tubes 22, 23, and 14) is a dark color low reflection surface 44b by being coated with a dark color film (not shown) made of a black paint or the like. The dark color is preferably black. The low reflection surface 44b has a cylindrical shape extending along the axis.

  As shown in FIG. 1, the imaging lens 45 is accommodated in the distal end portion of the axial tube 14 (holding portion) in the image light transmission tube 44. Therefore, the imaging lens 45 is provided in the hand portion 10. The imaging lens 45 is configured by a relay lens including a plurality of lenses in a row, and has a sufficiently large focal length corresponding to the distance between the lenses with the objective lens 43. As shown in FIG. 3, a portion of the image light transmission tube 44 between the objective lens 43 and the imaging lens 45 is a cavity 44e, and no lens, optical fiber, or the like is provided between the lenses 43 and 45. The inner tube 22 and thus the cylindrical low reflection surface 44b communicates the objective lens 43 and the imaging lens 45, and air as an image light transmission medium is connected to the cavity 44e in the inner tube 22 (low reflection surface 44b). (Gas) is contained.

  As shown in FIG. 1, an image sensor 42 is provided at the proximal end portion of the shaft tube 14. The image sensor 42 is configured by a CCD or a CMOS. The cable 5 is connected to the image sensor 42. As shown in FIG. 5, the cable 5 is pulled out from the proximal end portion of the hand portion 10 and connected to the CCU 3.

As shown in FIG. 1A, the illumination unit 30 includes a plurality of light sources 31 and an illumination optical system 32. Although the light source 31 is comprised by LED (light emitting diode), Preferably it is comprised by white LED, This invention is not limited to this. The light source 31 is held by the sleeve 13 so as to face the distal direction (left in FIG. 1A) from the sleeve 13. Therefore, the light source 31 is arranged so as to be shifted from the axis L. Optical axis L ₃₁ of the light source 31 is directed obliquely relative to the axis L. A plurality of light sources 31 are arranged in a ring shape in the circumferential direction of the sleeve 13 and surround the outer periphery of the distal end portion of the axial tube 14 (and thus the image light transmission tube 44).
One annular light source may be provided so as to surround the image light transmission tube 44.

  As shown in FIG. 3, the illumination optical system 32 includes an illumination light transmission tube 34, an exit lens 35 (illumination window), and a light guide member 33 (light guide portion). The illumination light transmission tube 34 is constituted by the outer tube 21 and the inner tube 22 of the insertion portion 20. A space 34e extending between the tubes 21 and 22 along the axis L is formed in an annular shape (cylindrical shape), and this annular cavity 34e constitutes an illumination light transmission path 34d in the insertion portion 10. ing. In the illumination light transmission path 34d, air (gas) is provided as an illumination light transmission medium. The outer peripheral surface (the inner surface of the outer tube 21) of the annular illumination light transmission path 34d is mirror-finished to form an outer reflecting surface 34a. Similarly, the inner peripheral surface of the annular illumination light transmission path 34d (the outer surface of the inner tube 22) is mirror-finished to form an inner reflection surface 34b. By polishing the inner surface of the outer tube 21 and the outer surface of the inner tube 22, or coating these surfaces with a mirror film (not shown) by vapor deposition or sputtering, these surfaces can be made mirror surfaces. Examples of the material for the mirror film include aluminum, but the present invention is not limited to this, and other glossy metals such as silver may be used.

  The inner reflection surface 34b is formed in a cylindrical shape that extends along the axis L while surrounding the low reflection surface 44b with the front and back surfaces of the low reflection surface 44b. The outer reflection surface 34a is concentric with the inner reflection surface 34b, surrounds the inner reflection surface 34b, and has a cylindrical shape extending along the axis L. Air (gas) as an illumination light transmission medium is provided between the reflecting surfaces 34a and 34b (between the outer tube 21 and the inner tube 22). The reflectance of the reflection surfaces 34a and 34b with respect to the illumination light is higher than the reflectance of the low reflection surface 44b with respect to the image light, and the absorption rate with respect to the illumination light of the reflection surfaces 34a and 34b is absorption with respect to the image light of the low reflection surface 44b. Lower than the rate.

As shown in FIG. 3, the exit lens 35 is configured by an annular concave lens. The exit lens 35 is fitted into the distal end portion of the illumination light transmission tube 34 (between the distal end portions of the outer tube 21 and the inner tube 22). The tip of the illumination light transmission path 34d is blocked by the exit lens 35.
Instead of the lens 35, an annular flat glass may be provided at the tip of the illumination light transmission tube 34.

  As shown in FIG. 4, the light guide member 33 has a conical ring shape having a center hole 33c. The light guide member 33 is made of transparent glass (illumination light transmission medium) and has translucency. The light guide member 33 may be made of a transparent optical resin (illumination light transmission medium) instead of glass.

  As shown in FIG. 3, the light guide member 33 is accommodated in the conical recess 52 a with the central axis aligned with the axis L. Accordingly, the light guide member 33 is interposed between the light source 31 and the insertion portion 20. The outer peripheral surface of the light guide member 33 is reduced in diameter toward the insertion portion 20 (and thus the illumination light transmission path 34d) and is in contact with the inner peripheral surface of the conical recess 52a. The end portion on the large diameter side of the light guide member 33 is directed to the light source 31, and the end portion on the small diameter side of the light guide member 33 is directed to the insertion portion 20. An annular end surface on the small diameter side of the light guide member 33 closes the base end portion of the illumination light transmission path 34d. A portion of the inner tube 22 and the tube portion 23a (that is, a portion of the image light transmission tube 44) is inserted through the center hole 33c. The inner peripheral surface of the center hole 33c is in contact with the outer peripheral surfaces of the inner tube 22 and the tube portion 23a. Therefore, the light guide member 33 surrounds the image light transmission tube 44.

  The outer peripheral surface of the light guide member 33 is mirror-finished by coating a mirror film (not shown) by vapor deposition or sputtering. As a result, the outer peripheral surface of the light guide member 33 constitutes the outer reflective surface 33a. Further, the outer peripheral surfaces of the inner tube 22 and the tube portion 23a are polished or mirror-finished by coating a mirror film (not shown) by vapor deposition or sputtering. The inner peripheral surface of the center hole 33c of the light guide member 33 is in contact with the outer peripheral surface of the inner tube 22 and the tube portion 23a that is made into a mirror surface, thereby forming a reflection surface 33b on the inner side of the light guide member 33. An illumination light transmission medium made of glass is formed between the reflecting surfaces 33a and 33b. Examples of the material for the mirror film include aluminum, but the present invention is not limited to this, and other glossy metals such as silver may be used.

The operation of the rigid endoscope 2 configured as described above will be described.
When observing an observation target such as an orbit of a human body with the endoscope 2, the insertion unit 20 is inserted into the observation target and illumination light is emitted from the light source 31. By arranging the light source 31 in the hand portion 10, the transmission distance of the illumination light can be shortened and the transmission efficiency can be increased. The illumination light obliquely enters the light guide member 33 and is condensed (converged) toward the front end side of the light guide member 33 while being reflected by the reflection surfaces 33a and 33b. Illumination light can be reliably reflected by making the reflection surfaces 33a and 33b mirror surfaces, and loss of illumination light can be suppressed. Further, every time the illumination light is reflected by the reflecting surfaces 33a and 33b, the angle formed by the traveling direction of the illumination light and the axis L is increased. This illumination light is introduced into the illumination light transmission path 34 d from the tip of the light guide member 33. And it is propagated to the front end side of the illumination light transmission path 34d while being reflected by the reflecting surfaces 34a and 34b. Illumination light can be reliably reflected by making the reflecting surfaces 34a and 34b mirror surfaces. Even if the incident angle of the illumination light to the reflecting surfaces 34a and 34b is small, it can be reliably reflected and transmitted. Therefore, the loss of illumination light can be reduced. This illumination light is irradiated so as to diffuse from the exit lens 35 and illuminates the observation target. By increasing the transmission efficiency of the illumination light, the observation object can be illuminated reliably.
The angle of the optical axis L ₃₁ of the angle and the light source 31 of the tapered outer peripheral surface of the light guide member 33 is appropriately set, can be adjusted emitting angle thus illumination range. That is, the emission angle can be increased by the light guide member 33, and the illumination range can be widened.

  The illuminated image light of the observation object enters the objective lens 43 and propagates to the proximal end side of the image light transmission path 44d. By making the inner surface of the light guide transmission tube 44 a black low reflection surface 44b, scattering of image light can be suppressed. The image light enters the imaging lens 45 straight from the objective lens 43 and is imaged on the image sensor 42 by the imaging lens 45. The image sensor 42 converts this image light into an electrical signal. This signal is sent to the CCU 3 and displayed on the monitor 4 as an observation image. By suppressing the scattering of the image light in the light guide transmission tube 44, the sharpness (contrast) of the observation image can be ensured. Furthermore, since the illumination light can be reliably prevented from entering the image light transmission path 44d by the inner tube 22, it is possible to more reliably prevent the observation image from becoming unclear.

According to the rigid endoscope 2, since the illumination light transmission medium of the illumination light transmission path 34d and the image light transmission medium of the image light transmission path 44d in the insertion section 20 are composed of air (gas), the insertion section The internal structure of 20 can be simplified. Therefore, the price of the rigid endoscope 2 can be reduced.
In addition, the insertion portion 20 can be made extremely fine without worrying about damage to the optical element in the insertion portion 20. That is, even if the insertion part 20 is extremely fine, for example, having a diameter of 2 mm to 3 mm or less, preferably 1 mm or less, when the insertion part 20 is bent by some bending load, the internal illumination light transmission medium and image light transmission medium are There is no damage. Further, since the objective lens 43 is provided at the distal end portion of the insertion portion 20, there is almost no possibility that the objective lens 43 is damaged even if the intermediate portion of the insertion portion 20 is curved.
Furthermore, if the bending is within the elastic deformation region of the outer tube 21 and the inner tube 22, when the bending load is released, the insertion portion 20 naturally returns to the original straight state by the elastic restoring force of the tubes 21 and 22. Return. Therefore, it is possible to reliably irradiate the observation target with the illumination light, and to reliably collect and observe the image of the observation target.

In the rigid endoscope 2, the used insertion portion 20 and the connection member 50 can be separated from the hand portion 10 and replaced with a new insertion portion 20 and connection member 50 each time it is used.
At the time of detachment, while the connecting member 50 is elastically deformed, the locking convex portion 51e is removed from the locking concave portion 11e, and the engagement between the pinion 61 and the rack 62 is released, and then the covering cylinder portion 51 of the connecting member 50 is removed. Pull out from the outer casing 11. Thereby, the connection member 50 and the hand portion 10 can be easily separated, and consequently, the insertion portion 20 and the hand portion 10 can be separated. Since the engagement between the pinion 61 and the rack 62 can be released by elastic deformation of the connecting member 50, it is not necessary to provide a separate engagement release mechanism.
As the connecting member 50 is pulled out from the outer casing 11, the connecting tube 23 is pulled out from the shaft tube 14. Therefore, the observation means 40 is separated between the connecting tube 23 and the shaft tube 14. Further, the illumination means 30 can be easily separated between the light source 31 and the light guide member 33.

  When attaching the new insertion portion 20 to the hand portion 10, the connecting tube 23 of the new insertion portion 20 is fitted into the shaft tube 14, and the covering cylinder portion 51 of the connecting member 50 integrated with the insertion portion 20 is removed. Fit into the outer periphery of the housing 11. At this time, by inserting the guide protrusion 11f into the guide groove 51f, the connection member 50, and thus the insertion portion 20 and the proximal portion 10 can be positioned in the circumferential direction. Further, the pinion 61 and the rack 62 are engaged with each other while the connecting member 50 is elastically deformed. Furthermore, by fitting the locking projection 51e into the locking recess 11e, the connecting member 50 and thus the insertion portion 20 and the hand portion 10 can be positioned in the axial direction.

  Subsequently, the pinion 61 of the position adjusting means 60 is turned to finely adjust the position of the insertion portion 20 and the axial tube 14 in the axial direction. Thereby, the inter-lens distance between the objective lens 43 and the imaging lens 45 can be finely adjusted according to the focal length. It is also possible to adjust the magnification of the observation image by the position adjusting means 60.

According to the endoscope 2, the connection member 50 itself elastically adheres to the outer casing 11, so that the connection member 50 itself functions as a seal member. Therefore, the hand portion 10 and the insertion portion 20 can be detachably attached without complicating the seal structure. Therefore, a sealing member such as an O-ring is not necessary, and not only the number of parts can be reduced, but also a housing for the sealing member need not be formed, and the configuration can be simplified. Furthermore, the structure of the position adjusting means 60 is also simple. Therefore, even if the insertion portion 20 is disposable, it is possible to reliably avoid an increase in cost, and the endoscope 2 suitable for the disposable specification of the insertion portion 20 can be provided.
Moreover, the trouble which wash | cleans the used insertion part 20 can be saved by replacing | exchanging to the new insertion part 20 at every use.

Next, another embodiment of the present invention will be described. In the following embodiments, the same reference numerals are given to the drawings for the same configurations as those already described, and the description thereof is omitted.
FIG. 6 shows a second embodiment of the present invention. In the endoscope 2A of the second embodiment, the illumination optical system 32 includes a transparent cylindrical member 36 as an illumination light transmission medium. The transparent cylinder member 36 has a cylindrical shape having a center hole 36 c and extends long along the axis L. The transparent cylinder member 36 is made of a transparent optical resin and has translucency and elasticity.

  The transparent cylindrical member 3 is loaded in the illumination light transmission path 34d between the outer tube 21 and the inner tube 22. The outer peripheral surface of the transparent cylindrical member 36 is in contact with the inner peripheral surface forming the mirror surface of the outer tube 21 to constitute the outer reflective surface 36a. The inner peripheral surface of the center hole 36c is in contact with the outer peripheral surface forming the mirror surface of the inner tube 22, thereby forming the inner reflective surface 36b. The annular base end surface (right end in FIG. 6) of the transparent cylindrical member 36 abuts on or is close to the annular distal end surface of the light guide member 33. An annular front end surface (left end in FIG. 6) of the transparent cylindrical member 36 abuts on or is close to the emission lens 35. The inner tube 22 and the image optical system 41 pass through the center hole 36 c of the transparent cylinder member 36.

  In addition, you may decide to comprise the reflective surface 36a or 36b with this mirror surface film | membrane by coating a mirror surface film (illustration omitted) by vapor deposition, sputtering, etc. on the outer peripheral surface or inner peripheral surface of the transparent cylinder member 36. In that case, the inner peripheral surface of the outer tube 21 or the outer peripheral surface of the inner tube 22 may not be a mirror surface. Examples of the material for the mirror film include aluminum, but the present invention is not limited to this, and other glossy metals such as silver may be used.

According to the rigid endoscope 2A of the second embodiment, the illumination light is reliably propagated from the light guide member 33 to the exit lens 35 by configuring the illumination light transmission medium with the cylindrical member 36 made of transparent resin. It is possible to reduce the loss of illumination light and to reliably illuminate the observation target.
Further, by giving elasticity to the transparent cylindrical member 36, it is possible to prevent the illumination light transmission medium in the insertion portion 20 from being damaged even if the insertion portion 20 is bent slightly.

  FIG. 7 shows a third embodiment of the present invention. In the endoscope 2 </ b> B of the third embodiment, the image optical system 41 includes a transparent cylindrical member 46 in addition to the illumination optical system 32 including the transparent cylindrical member 36. The transparent cylindrical member 46 has a wire shape with a circular cross section that extends straight along the axis L. The transparent cylindrical member 46 is made of a transparent optical resin and has translucency and elasticity. The transparent cylindrical member 46 constitutes an image light transmission medium of the image optical system 41.

  The transparent cylindrical member 46 is loaded in the image light transmission path 44 d inside the image light transmission tube 44. The outer peripheral surface of the transparent cylindrical member 46 is in contact with the inner peripheral surface forming the dark color surface of the image light transmission tube 44, thereby constituting the low reflection surface 46b. The distal end portion (left end portion in FIG. 7) of the transparent cylindrical member 46 abuts on or is close to the objective lens 43. The base end portion (right end portion in FIG. 7) of the transparent cylindrical member 46 is disposed at substantially the same axial position as the base end portion of the inner tube 22, and faces away from the imaging lens 45. Note that the base end portion of the transparent cylindrical member 46 may extend until it comes into contact with or close to the imaging lens 45.

  In addition, the low reflective surface 46b may be comprised with this dark color film | membrane by coating the outer peripheral surface of the transparent cylindrical member 46 with a dark color film (illustration omitted) with a dark color paint etc. In that case, the inner peripheral surface of the tube 44 may not be dark.

According to the rigid endoscope 2B of the third embodiment, the image light is reliably propagated from the objective lens 43 to the imaging lens 45 by configuring the image light transmission medium with the cylindrical material 46 made of transparent resin. Can do.
Further, by giving elasticity to the transparent cylindrical member 36 and the transparent cylindrical member 46, the illumination light transmission medium and the image light transmission medium in the insertion portion 20 are not damaged even if the insertion portion 20 is bent slightly. can do.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the illumination light transmission medium in the illumination light transmission path 34d may be configured with a liquid such as water, and the image light transmission medium in the image light transmission path 44d may be configured with a liquid such as water.
In the third embodiment, by omitting the transparent cylindrical member 36, the illumination light transmission path may be made hollow as in the first embodiment, and air (gas) may be used as the illumination light transmission medium.
In the third embodiment, the inner tube 22 may be omitted. In that case, it is preferable to coat a mirror film on the inner peripheral surface of the center hole 36 c of the transparent cylindrical member 36 and coat a dark color film on the outer peripheral surface of the transparent cylindrical member 46. A portion on the inner peripheral side of the transparent cylindrical member 36 or a portion on the outer peripheral side of the transparent cylindrical member 46 may also serve as the inner tube.
The outer reflective surface 33a may be configured by providing a mirror film on the inner peripheral surface of the conical recess 52a. Further, the inner reflection surface 33b may be configured by providing a mirror film on the inner peripheral surface of the center hole 33c of the light guide member 33. The light guide member 33 may be omitted, the inside of the conical recess 52a may be a cavity, and the air (gas) in the conical recess 52a may be used as the illumination light transmission medium. In this case, it is preferable to coat a reflection film such as a mirror film on the inner peripheral surface of the conical recess 52a.
The attaching / detaching portion 51 of the connecting member 50 may be elastically and separably attached to the peripheral surface of the proximal end portion of the insertion portion 10, and the joining portion 52 may be integrally joined to the hand portion 10.
The outer tube 21 or the inner tube 22 may be made of a hard resin.

  The present invention is applicable to, for example, a medical endoscope.

L axis 2, 2A, 2B rigid endoscope 10 proximal portion 20 insertion portion 21 outer tube 22 inner tube 31 light source 32 illumination optical system 34a outer reflection surface 34b inner reflection surface 34e annular cavity 36 transparent cylindrical member (illumination light transmission medium )
36a Outer reflecting surface 36b Inner reflecting surface 36c Center hole 41 Image optical system 43 Objective lens (objective element)
44 Image light transmission tube (image light transmission member)
44b Low reflection surface 44e Cavity 45 Imaging lens (imaging element)
46 Transparent cylindrical member (image light transmission medium)
46b Low reflective surface

Claims (8)

A hand portion, an insertion portion extending linearly along the axis from the hand portion, an illumination optical system that transmits illumination light from a light source to an observation target, and an image optical system that transmits image light of the observation target A rigid endoscope comprising:
The image optical system extends along the axis so as to communicate the objective element provided at the distal end of the insertion portion, the imaging element provided at the hand portion, and the objective element and the imaging element. An image light transmission medium made of any one of gas, liquid, and translucent resin is provided inside the low reflection surface.
The illumination optical system includes a cylindrical inner reflection surface extending along the axis so as to surround the low reflection surface, and a cylindrical outer reflection surface extending along the axis so as to surround the inner reflection surface, A rigid endoscope, wherein an illumination light transmission medium made of any of gas, liquid, and translucent resin is provided between an inner reflection surface and the outer reflection surface.   The insertion portion includes a metal outer tube extending along the axis, and a metal inner tube housed in the outer tube and extending along the axis, and the outer tube and the inner tube The rigid endoscope according to claim 1, wherein the illumination light transmission medium is accommodated therebetween, and the image light transmission medium is accommodated inside the inner tube.   The inner surface of the outer tube constitutes the outer reflecting surface, the outer surface of the inner tube constitutes the inner reflecting surface, and an annular cavity is formed between the outer tube and the inner tube. The rigid endoscope according to claim 2, wherein gas or liquid is accommodated as the illumination light transmission medium.   The inner surface of the inner tube constitutes the low reflection surface, and the interior of the inner tube becomes a cavity, and gas or liquid is accommodated in the cavity as the image light transmission medium. The rigid endoscope according to 1.   The illumination optical system includes a transparent cylindrical member made of a translucent resin having a central hole and extending along the axis, and an outer peripheral surface of the transparent cylindrical member constitutes the outer reflective surface, and the central hole 3. The rigid endoscope according to claim 1, wherein an inner peripheral surface of the first optical axis constitutes the inner reflection surface, and the image optical system passes through the center hole.   2. The image optical system includes a transparent cylindrical member made of a translucent resin extending along the axis, and an outer peripheral surface of the transparent cylindrical member constitutes the low reflection surface. The rigid endoscope according to 2, or 5.   The reflectance of the inner reflective surface and the outer reflective surface with respect to the illumination light is higher than the reflectance of the low reflective surface with respect to the image light, and the absorptivity of the inner reflective surface and the outer reflective surface with respect to the illumination light is as follows: The rigid endoscope according to any one of claims 1 to 6, wherein an absorptance with respect to the image light of the low reflection surface is lower.   The rigid endoscope according to any one of claims 1 to 7, wherein the outer reflection surface and the inner reflection surface are mirror surfaces, and the low reflection surface is a dark color surface.

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