JP2008206624A - Tip part for ultrafine diameter electronic endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tip part for an ultrafine diameter electronic endoscope, improving luminous intensity distribution characteristics by providing a luminous intensity distribution optical element without enlarging the outer diameter of the tip of an insert part, or decreasing the number of light guide fibers, and improving insertion performance by forming a tip angular part to be smoothly round. <P>SOLUTION: A tip cover cylinder 18, comprising the luminous intensity distribution optical element 16 for enlarging a luminous intensity distribution angle of illumination light outgoing from a light guide fiber bundle 15 fixed on the inner side, is formed roughly cylindrical, and it is fitted and fixed to the outer circumference of a tip main body outer cylinder 2 from the tip side. The luminous intensity distribution optical element 16 is thus fixed to such a position as to face an outgoing end surface 15a of the light guide fiber bundle 15. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tip portion of an ultrafine electronic endoscope.

  The diameter of the insertion part of a general electronic endoscope is about 10 mm for gastrointestinal and other digestive tract examinations, and about 5 mm for bronchial examinations. It is necessary to use a very small diameter of less than 3 mm.

  The tip of such an ultra-thin electronic endoscope is fully equipped with an observation function, an illumination function, and a bending function that bends the vicinity of the distal end of the insertion portion by remote control from the hand side due to space constraints. (For example, Patent Documents 1 and 2).

  FIG. 8 is a plan sectional view of the distal end portion of a conventional ultra-fine diameter electronic endoscope. The objective optical element for observation is positioned at the axial position of the substantially cylindrical distal end main body outer cylinder 91 disposed at the distal end of the insertion portion distal end. The objective imaging element holding cylinder 94 that holds the 92 and the solid-state imaging element 93 is disposed, and an observation window 95 is attached to the distal end of the objective imaging element holding cylinder 94. A light guide fiber bundle 96 for illumination is filled and arranged in a space between the inner periphery of the outer cylinder 91.

FIG. 9 is a front view of the distal end portion of such an ultra-thin electronic endoscope. Since the cross-sectional shape of the solid-state image sensor 93 disposed behind the observation window 95 is substantially rectangular, The exit end portion of the guide fiber bundle 96 is formed of two bundles having a cross-sectional shape surrounded by an arc and a string that can pass straight through a space that does not interfere with the solid-state imaging device 93.
JP-A-7-275194 JP 2004-159773 A

  As shown in FIG. 8, the exit end surface 96 a of the light guide fiber bundle 96 is exposed at the distal end surface of the insertion portion at substantially the same position as the observation window 95 at the distal end portion of the conventional ultrafine diameter electronic endoscope. Arranged in a state.

  However, in such a configuration, the peripheral part of the endoscope observation field may not be sufficiently illuminated due to the light guide characteristics of the light guide fiber, so that the light distribution optical element for widening the light distribution angle of the illumination light Is preferably disposed facing the emission end face 96 a of the light guide fiber bundle 96.

  However, space limitations are extremely large in ultra-thin electronic endoscopes, so it is necessary to attach a light distribution optical element without sacrificing such things as increasing the outer diameter of the distal end of the insertion section or reducing the number of light guide fibers. When it was not possible, it was accepted, and it was used with insufficient light distribution.

  In addition, since the distal end main body outer cylinder 91 exposed on the outer surface of the most distal end portion of the ultra-fine diameter electronic endoscope serves as a base for fixing the emission end portion of the light guide fiber bundle 96, the emission end surface 96a is polished. As a result, as shown in FIG. 8, the leading end corner 91a of the leading end body outer cylinder 91 is edged to obtain a smooth insertion property. There was a case where trouble occurred.

  The present invention improves the light distribution characteristics by providing a light distribution optical element without increasing the outer diameter of the distal end of the insertion section or reducing the number of light guide fibers. It is an object of the present invention to provide a distal end portion of an ultra-fine diameter electronic endoscope that can be formed and improved in insertability.

  In order to achieve the above object, the distal end portion of the ultra-thin electronic endoscope of the present invention has an observation objective optical element and an axial position of the substantially cylindrical distal end main body outer cylinder disposed at the distal end of the insertion portion. An objective imaging element holding cylinder for holding the solid-state imaging element is arranged, an observation window is attached to the tip of the objective imaging element holding cylinder, and the outer peripheral part of the objective imaging element holding cylinder and the inner peripheral part of the distal end main body outer cylinder The light distribution angle of the illumination light emitted from the light guide fiber bundle at the distal end portion of the ultra-fine diameter electronic endoscope having a configuration in which the light guide fiber bundle for illumination is filled and arranged in the space provided between A front end cover tube having a light distribution optical element for spreading inside is formed in a substantially cylindrical shape, and is fitted and fixed from the front end side to the outer periphery of the outer cylinder of the front end portion body. Fiber bundle injection In which is fixed to a position facing the surface.

It should be noted that the present invention is preferably applied to the distal end portion of an ultra-fine diameter electronic endoscope having a maximum outer diameter size near the distal end of the insertion portion of less than 3 mm in diameter.
The light distribution optical element may be formed in a shape surrounded by an arc and a string, and the back surface of the light distribution optical element may be a light scattering surface. Further, the arc-shaped portion of the light distribution optical element may abut against the stepped portion formed on the inner periphery of the tip cover cylinder so that it cannot escape forward from the tip cover cylinder.

  The tip inner cylinder having an arcuate portion whose outer edge is formed along the inner peripheral surface of the tip cover tube and a cutout portion formed along the chord-like portion of the light distribution optical element is a tip cover tube. It may be fixed together with the light distribution optical element and disposed at a position surrounding the observation window, and positioning means for positioning the distal end main body outer cylinder and the distal inner cylinder in the direction around the axis is provided. May be.

  According to the present invention, the distal end cover cylinder in which the light distribution optical element for expanding the light distribution angle of the illumination light emitted from the light guide fiber bundle is fixed inside is formed in a substantially cylindrical shape, and the distal end main body outer cylinder The outer periphery of the optical guide is fixedly fitted from the front end side, and thereby the light distribution optical element is fixed at a position facing the exit end face of the light guide fiber bundle, so that the outer diameter of the insertion portion front end is increased or the light guide is increased. Without reducing the number of fibers, a light distribution optical element is provided at the tip of the ultra-thin electronic endoscope to improve the light distribution characteristics. Can be improved.

  An objective imaging element holding cylinder for holding the observation objective optical element and the solid-state imaging element is arranged at the axial position of the substantially cylindrical distal end main body outer cylinder arranged at the distal end of the insertion section, and the objective imaging element holding is held. A configuration in which an observation window is attached to the tip of the cylinder, and a light guide fiber bundle for illumination is filled and arranged in a space provided between the outer periphery of the objective imaging device holding cylinder and the inner periphery of the outer cylinder of the tip body A tip cover tube with a light distribution optical element fixed inside for forming a light distribution angle of illumination light emitted from the light guide fiber bundle is formed in a substantially cylindrical shape at the tip of an ultra-thin electronic endoscope having Then, it is fitted and fixed to the outer periphery of the distal end main body outer cylinder from the distal end side, whereby the light distribution optical element is fixed at a position facing the exit end face of the light guide fiber bundle.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional plan view of the distal end portion of the ultra-thin electronic endoscope, FIG. 2 is a side cross-sectional view, and FIG. 3 is a front view.

The flexible insertion portion 1 to be inserted into the body is formed such that the maximum diameter near the tip is less than 3 mm.
The distal end of the insertion portion 1 is connected to a substantially cylindrical distal end portion main body outer cylinder 2 formed of a metal such as stainless steel, and the flexible and flexible electrically insulating outer tube 3 that covers the insertion portion 1 is provided. The distal end portion is covered and fixed to the middle portion of the outer periphery of the distal end main body outer cylinder 2 from the rear.

  A metal objective element holding cylinder 6 that holds an objective optical system 4 (observation objective optical element) composed of a plurality of lenses is disposed at the axial position of the distal end main body outer cylinder 2. An observation window 7 is provided at the tip of the. The observation window 7 is located so as to protrude forward from the distal end surface of the distal end main body outer cylinder 2.

  The objective element holding cylinder 6 is formed in a cylindrical shape excluding the outer peripheral part near the rear end, and a cylindrical insulating cylinder 8 made of a hard electrically insulating material is fitted on the outer periphery of the cylindrical part. ing. The tip of the insulating cylinder 8 protrudes slightly forward from the tip of the objective element holding cylinder 6 and is substantially flush with the observation window 7.

  Reference numeral 9 denotes a solid-state image pickup element 5 for picking up an endoscope observation image projected by the objective optical system 4 and a metal image pickup element holding cylinder for holding a drive circuit thereof, and a shield for preventing noise. It also has a function.

  The imaging element holding cylinder 9 is formed in a substantially rectangular shape having a vertically long cross section in accordance with the shape of the solid-state imaging element 5, and the tip portion thereof is fitted to the outer periphery of the rear end of the objective element holding cylinder 6 to hold the objective element. The cylinder 6 is integrally connected and fixed, and the objective element holding cylinder 6 and the imaging element holding cylinder 9 form an objective imaging element holding cylinder. Reference numeral 10 denotes an electrically insulating insulating tape wound around the outer periphery of the image sensor holding cylinder 9, and 11 denotes a signal cable inserted through the insertion portion 1.

  A metal tip end main body inner cylinder 14 is disposed inside the front end portion of the tip end main body outer cylinder 2, and the insulating cylinder 8 is fitted into a through hole formed at the axial position of the tip end main body inner cylinder 14. They are inserted and held, and they are bonded together to form an integrated state (refer to FIG. 5 described later for the cross-sectional shape of the distal end main body inner cylinder 14).

  Reference numeral 15 denotes a light guide fiber bundle for illumination that is filled in a space provided between the outer periphery of the objective imaging element holding cylinders 6 and 9 and the inner periphery of the distal end main body outer cylinder 2. In the light guide fiber bundle 15, as shown in FIG. 4 which is shown as a single unit, a hard molded portion 15A filled in the space inside the distal end main body outer cylinder 2 and hardened with an adhesive in the space shape, and a flexible Three regions of a flexible portion 15B covered with a protective tube 13 and inserted into the insertion portion 1 and a transition portion 15C between the hard molded portion 15A and the flexible portion 15B are formed.

  Since the cross-sectional shape of the hard molded portion 15A is arranged in the space on both the left and right sides of the solid-state imaging device 5 having a vertically long cross-sectional shape, the whole is formed with an arc on the outer edge side along the inner peripheral surface of the distal end main body 2 and imaging. It is formed in a shape surrounded by inner side strings along the outer surface of the element holding cylinder 9, and the emission end face 15a is also in that shape.

  The outer edge of the distal end main body inner cylinder 14 is scraped off in accordance with the shape of the string on the exit end face 15 a, and the exit end of the light guide fiber bundle 15 is formed between the distal end main body outer cylinder 2 and the distal end main body inner cylinder 14. It is inserted in the state filled in the space between and joined to it.

  As shown in FIG. 5, the polishing of the injection end face 15a is a state in which the hard molded portion 15A is inserted and fixed between the distal end main body outer tube 2 and the distal end main body inner tube 14. The objective element holding cylinder 6 is not attached. Therefore, the distal end surfaces of the distal end main body outer cylinder 2 and the distal end main body 14 and the emission end surface 15a of the light guide fiber bundle 15 are completely flush with each other.

  As shown in FIGS. 1, 2, and 5, two light distribution optical elements 16 for expanding the light distribution angle of illumination light emitted from the emission end face 15a of the light guide fiber bundle 15, A tip inner cylinder 17 disposed so as to fill a space between the two light distribution optical elements 16 is fixed to the inside of a tip cover cylinder 18 formed in a cylindrical shape.

  Then, the tip cover cylinder 18 is fitted on the outer periphery of the vicinity of the tip of the tip portion main body outer cylinder 2 and bonded and fixed, whereby the light distribution optical element 16 faces the emission end face 15 a of the light guide fiber bundle 15. It is fixed to. Two light distribution optical elements 16 are provided at symmetrical positions, but one illustration is omitted in FIG.

  Each light distribution optical element 16 formed of transparent plastic or glass is formed in a shape surrounded by an arc and a string in accordance with the shape of the exit end face 15 a of the light guide fiber bundle 15.

  Although the surface of the light distribution optical element 16 is formed in a smooth surface, the back surface is a light scattering surface having small irregularities, and the illumination light emitted from the emission end face 15a of the light guide fiber bundle 15 is wide. Is diffused and emitted forward.

  Then, the stepped portion formed on the arc-shaped outer edge portion of the light distribution optical element 16 abuts on the stepped portion formed on the inner periphery of the tip cover cylinder 18 so that the light distribution optical element 16 becomes the tip cover cylinder. It is impossible to escape forward from within 18. The tip inner cylinder 17 is also formed in a shape having a similar stepped portion so that it cannot escape forward from the tip cover cylinder 18. In each figure, the portion indicated by the symbol A is the stepped portion.

  The distal end inner cylinder 17 formed of a metal material such as stainless steel is formed in the same cross-sectional shape as the distal end main body inner cylinder 14. That is, the outer edge of the distal end inner cylinder 17 is formed by an arc-shaped portion having a shape along the inner peripheral surface of the distal end cover cylinder 18 and a notched portion notched along the chord-shaped portion of the light distribution optical element 16. The distal end cover tube 18 is fixed together with the light distribution optical element 16 with an adhesive and is disposed at a position surrounding the observation window 7.

  In this way, at the distal end portion of the ultra-thin diameter electronic endoscope of the present embodiment, the light guide fiber bundle 15 is obtained without increasing the outer diameter of the distal end of the insertion portion 1 or reducing the number of light guide fibers. The light distribution optical element 16 can be arranged so as to face the emission end surface 15a of the light and the light distribution characteristics can be improved. Further, the tip corner 18a of the tip cover cylinder 18 can be formed in a smooth rounded shape without an edge or the like, thereby ensuring good insertability.

  FIGS. 6 and 7 show the distal end portion of an ultra-fine diameter electronic endoscope according to the second embodiment of the present invention, in order to position the distal end main body outer cylinder 2 and the distal end inner cylinder 17 in the direction around the axis. The positioning means B is provided, and the other configuration is the same as that of the first embodiment.

  The positioning means B of this embodiment is composed of a notch formed on the outer periphery of the distal end main body outer cylinder 2 and a protrusion formed so as to protrude from the distal inner cylinder 17 side so as to engage with the notch. Has been. However, other configurations may be adopted.

  By providing such positioning means B, the light distribution optical element 16 can be mounted as a light guide only by attaching the tip cover cylinder 18 in which the light distribution optical element 16 and the tip inner cylinder 17 are assembled to the distal end main body outer cylinder 2. The fiber bundle 15 can be accurately set at a position facing the emission end face 15a.

It is a plane sectional view of the tip part of the ultra-fine diameter electronic endoscope of the 1st example of the present invention. It is side surface sectional drawing of the front-end | tip part of the ultra-thin diameter electronic endoscope of 1st Example of this invention. It is a front view of the front-end | tip part of the ultra-thin diameter electronic endoscope of 1st Example of this invention. It is a perspective view of the light guide fiber bundle simple substance of the 1st example of the present invention. It is a disassembled perspective view of the most distal part of the front-end | tip part of the ultra-thin diameter electronic endoscope of 1st Example of this invention. It is side surface sectional drawing of the front-end | tip part of the ultra-fine diameter electronic endoscope of 2nd Example of this invention. It is a disassembled perspective view of the most advanced part of the front-end | tip part of the ultra-thin diameter electronic endoscope of 2nd Example of this invention. It is a plane sectional view of the tip part of the conventional ultra-thin diameter electronic endoscope. It is a front view of the front-end | tip part of the conventional ultra-thin diameter electronic endoscope.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insertion part 2 Tip part main body outer cylinder 4 Objective optical system (objective optical element for observation)
5 Solid-state imaging device 6 Objective element holding cylinder (Objective imaging element holding cylinder)
7 Observation window 9 Image sensor holding cylinder (objective image sensor holding cylinder)
DESCRIPTION OF SYMBOLS 15 Light guide fiber bundle 15a Outgoing end surface 16 Light distribution optical element 17 End inner cylinder 18 End cover cylinder 18a End corner A Step part B Positioning means

Claims (7)

An objective imaging element holding cylinder for holding the observation objective optical element and the solid-state imaging element is arranged at the axial position of the substantially cylindrical distal end main body outer cylinder arranged at the distal end of the insertion section, and the objective imaging element holding is held. An observation window is attached to the tip of the cylinder, and a light guide fiber bundle for illumination is filled and disposed in a space provided between the outer periphery of the objective imaging element holding cylinder and the inner periphery of the outer cylinder of the tip body. In the tip of the ultra-thin electronic endoscope having the structure
A distal end cover cylinder in which a light distribution optical element for expanding a light distribution angle of illumination light emitted from the light guide fiber bundle is fixed inside is formed in a substantially cylindrical shape, and is distal to the outer periphery of the distal end main body outer cylinder. A distal end portion of an ultra-fine diameter electronic endoscope, which is fixedly fitted from the side, whereby the light distribution optical element is fixed at a position facing an emission end face of the light guide fiber bundle.   The distal end portion of the ultrafine-diameter electronic endoscope according to claim 1, wherein the maximum outer diameter size near the distal end of the insertion portion is less than 3 mm in diameter.   The distal end portion of the ultrafine-diameter electronic endoscope according to claim 1 or 2, wherein the light distribution optical element is formed in a shape surrounded by an arc and a string.   The tip portion of the ultrafine-diameter electronic endoscope according to claim 3, wherein a back surface of the light distribution optical element is a light scattering surface.   5. The ultrafine diameter according to claim 3 or 4, wherein the arc-shaped portion of the light distribution optical element is in contact with a step portion formed on the inner periphery of the tip cover cylinder so that it cannot escape forward from the tip cover cylinder. The tip of an electronic endoscope.   A tip inner cylinder having an arcuate portion whose outer edge is shaped along the inner peripheral surface of the tip cover tube and a cutout portion cut out along the chord-like portion of the light distribution optical element is the tip cover. The distal end portion of the ultrafine-diameter electronic endoscope according to claim 3, 4 or 5, which is fixed together with the light distribution optical element in a cylinder and disposed at a position surrounding the observation window.   7. The distal end portion of the ultra-fine diameter electronic endoscope according to claim 6, wherein positioning means for positioning the distal end portion main body outer cylinder and the distal end inner cylinder in the direction around the axis is provided.

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