JP5377258B2 - Front end structure of perspective endoscope - Google Patents

Description

  The present invention relates to a distal end structure of a perspective endoscope.

  In a perspective endoscope (including an ultrasonic endoscope), generally, as shown in FIG. 6, a tip slope 92 facing obliquely forward is formed on a tip body 91 arranged at the tip of the insertion portion. The prism 90 is disposed in the prism accommodating hole 93 formed in the tip inclined surface 92.

  A cover lens 95 is fixed to the countersunk hole 94 formed in the opening of the prism accommodating hole 93, and the receiving plate 96 fixed to the bottom surface of the countersink hole 94 is in close contact with the back surface of the cover lens 95. A region (shaded portion shown in FIG. 7) 98 outside the light image incident surface 97 of the prism 90 is bonded and fixed (Patent Document 1).

  In addition, a structure has been proposed in which a U-shaped auxiliary frame is bonded to the periphery of the prism except for the light incident surface and the output surface, and this auxiliary frame is joined to the inner wall of the prism accommodating hole (Patent Document 2).

Japanese Patent Laid-Open No. 2000-201886 JP 2008-220711 A

  However, a sufficiently large joining area is not secured in the region 98 outside the light image incident surface 97 of the prism 90, and the objective lens barrel 100 is arranged so that the tip faces the light image exit surface 99 of the prism 90. When the movement of the signal cable 101 in the axial direction is transmitted to the prism 90 through the wire, a peeling force acts on the joint between the receiving plate 96 and the prism 90, so that the joint is broken and the prism 90 becomes the prism housing hole. 93 may fall out. The structure using the U-shaped auxiliary frame also has the same problem although the bonding strength is improved.

  Furthermore, in any of the conventional structures, the position of the cover lens (front group lens, objective lens), prism, and rear group lens barrel that are sequentially positioned in the optical axis direction must be adjusted in the tip body. There was a problem that shape accuracy was required and its assemblability was very poor.

  The present invention provides a distal end structure of a perspective endoscope in which the cover lens, the prism, and the rear lens barrel are easily assembled and the prism does not easily fall off, based on the above problem awareness. Objective.

  The present invention has a conventional structure in which the prism is accommodated in the prism housing hole of the tip body, the cover lens is accommodated in the countersink-shaped hole, the rear group lens barrel is accommodated in the lens barrel hole, and positioned and fixed in the accommodated state. Based on the viewpoint that if the cover lens, prism, and objective tube are integrated in advance and inserted into the optical element storage hole of the tip main body, the assemblability is greatly improved and the prism does not fall off. It has been completed.

  That is, in the distal end structure of the perspective endoscope according to the present invention, the cover lens is located on the tip inclined surface formed in the distal end body of the insertion portion, and the prism and the rear group barrel are located behind the cover lens. In the distal end structure of the perspective type endoscope, the cover lens housing hole for housing and fixing the cover lens, the prism fixing arm for fixing the prism, and the rear group barrel fixing arm for fixing the rear group barrel are integrated. An auxiliary frame having a cover frame, a prism, and a rear group lens barrel are accommodated in a front optical element housing hole formed in the front end body.

  It is practical that the prism fixing arm and the rear lens barrel fixing arm of the auxiliary frame are formed by the same pair of arms.

  It is preferable that the distal end optical element storage hole of the distal end main body allows the auxiliary frame assembly to be inserted from the operation unit side, and the distal end main body is positioned at the distal end of the storage hole to form a retaining positioning edge.

  More specifically, the auxiliary frame is provided with an inclined plate portion having a cover lens accommodation hole that is flush with the tip inclined surface of the tip portion main body, and a pair of arms extending in parallel from the inclined plate portion. Can be bonded to the auxiliary frame at the contact portion with the pair of arms and the contact portion with the inclined plate portion, and the rear lens barrel can be bonded to the pair of arms at the rear portion of the prism.

  The distal end structure of the perspective endoscope according to the present invention is provided with an auxiliary frame for fixing the cover lens, the prism, and the rear group barrel, and the cover lens, the prism, and the rear group barrel are fixed to the front end body. Since the tip optical element storage hole for inserting the auxiliary frame assembly is formed, the fixing work and the positioning work can be performed before the tip optical element is attached to the tip portion main body. Accordingly, the fixing strength can be increased by integrating the auxiliary frame, the cover lens, the prism, and the rear group barrel, and the assemblability can be further improved.

It is a front view which shows the whole perspective type endoscope provided with the front-end | tip part structure by this invention. It is sectional drawing which shows the state which inserted the auxiliary | assistant frame coupling body which fixed the front-end | tip optical element in the optical-element accommodation hole of the front-end | tip part main body. It is a perspective view which shows the state before fixation of the cover lens and prism with respect to an auxiliary | assistant frame. FIGS. 4A and 4B are a plan view and a perspective view of a state in which a cover lens and a prism are coupled (adhered) to an auxiliary frame, showing an embodiment of a distal end structure of a perspective endoscope according to the present invention. . It is a perspective view which shows the state of the auxiliary | assistant frame coupling body which fixed the cover lens, the prism, and the rear group lens barrel (front end optical element) with respect to the auxiliary | assistant frame. It is a side surface fragmentary sectional view of the front-end | tip part of the insertion part of the conventional ultrasonic endoscope. It is a partial exploded perspective view of the conventional prism holding part.

  1 to 5 show an embodiment of the endoscope distal end structure according to the present invention. FIG. 1 shows the overall configuration of the ultrasonic endoscope. The operation unit 2 is connected to the proximal end of the insertion unit 1, and the bending unit 3 formed in the distal end region of the insertion unit 1 is connected to the operation unit 2. The operation knob 4 provided can be arbitrarily bent by rotating it.

  The distal end portion 10 of the insertion portion 1 includes a distal end portion main body 11 coupled to the distal end of the bending portion 3 and an ultrasonic probe 12 coupled to the distal side of the distal end portion main body 11. The ultrasonic probe 12 of this embodiment is of a so-called convex type that scans in a fan shape from the oblique rear to the oblique front with the arrow A as the center. The observation optical system disposed in the tip body 11 is a front perspective type with the arrow B as the observation optical axis. 6 is an optical observation signal side connector connected to a video processor / light source device (not shown), and 7 is an ultrasonic signal side connector connected to an ultrasonic diagnostic device (not shown). The ultrasonic probe 12 is shown only in FIG. 1 and is not shown in FIG.

  As shown in FIG. 2, the distal end portion main body 11 of the insertion portion 1 is formed with a distal end inclined surface 13 inclined obliquely forward (inclined with respect to a plane orthogonal to the extension direction of the insertion portion 1) on the side surface portion. . Further, the distal end main body 11 is formed with a linear optical element accommodation hole 14 opening in the distal end inclined surface 13 at the center thereof, and a retaining positioning edge 15 is formed at the distal end of the optical element accommodation hole 14. Projecting inward.

  In the present embodiment, the cover lens is inserted into the auxiliary frame 21 inserted into the distal optical element accommodation hole 14 without providing the cover lens accommodation hole for accommodating and fixing the cover lens (front lens group, concave lens) 20 in the distal end body 11. An accommodation hole 22 is provided. That is, as is apparent from FIG. 3, the auxiliary frame 21 has an inclined plate portion 23 that is flush with the distal end inclined surface 13 of the distal end portion main body 11, and a cover lens accommodation hole ( A counterbore 22) and an optical path hole 24 (FIG. 2) are formed. On the back surface of the inclined plate portion 23, an air layer forming recess 25 (FIG. 2) is formed so as to be positioned above the optical path hole 24 in the figure. The auxiliary frame 21 is integrally formed with a pair of prism fixing arms 26 that are positioned on both sides of the optical path hole 24 and extend symmetrically and parallel to each other with respect to the center of the optical path hole 24.

  As is apparent from FIG. 3, the prism 27 includes an incident surface (inner surface reflection surface) 27 a that contacts the back surface of the inclined plate portion 23 of the auxiliary frame 21, both side surfaces 27 b that contact the pair of prism fixing arms 26, and a total reflection surface. 27c and an emission surface 27d. In this prism 27, the portion other than the optical path hole 24 and the air layer forming concave portion 25 of the incident surface 27a (the hatched portion in FIG. 4B) is bonded and fixed to the back surface of the inclined plate portion 23, and both side surfaces 27b (same as above). Are bonded and fixed to the inner surfaces of the pair of prism fixing arms 26. Thus, since the prism 27 is bonded and fixed to the auxiliary frame 21 on three surfaces, high adhesive strength can be obtained. Further, since the entire periphery of the cover lens 20 is also bonded and fixed to the cover lens accommodation hole (counterbore hole) 22, high adhesive strength can be obtained similarly.

  The rear part of the prism fixing arm 26 simultaneously constitutes the rear group barrel fixing arm 26a. As shown in FIG. 2, the rear group barrel 28 contains an aperture 28 a and a rear group lens 28 b therein, and a pair of rear group barrel fixing arms 26 a are arranged on both side surfaces of the rear group barrel 28. And are fixedly adhered to both side surfaces. The bonding surface of the rear group barrel fixing arm 26a and the rear group barrel 28 is a flat surface in the illustrated example, but may be formed of a curved surface.

  The cover lens 20, the prism 27, and the rear group barrel 28 are positioned and accurately fixed with respect to the cover lens housing hole 22, the prism fixing arm 26, and the rear group barrel fixing arm 26a of the auxiliary frame 21, respectively. Thus, the auxiliary frame combined body 30 is formed (FIG. 5). At the time of this adhesive fixing, the subject image by the cover lens 20, the prism 27, and the rear group barrel 28 can be positioned while observing with an image sensor. That is, the incident light from the cover lens 20 is incident from the incident surface 27a of the prism 27, is reflected twice by the total reflection surface 27c and the inner surface of the air layer forming recess 25 of the incident surface 27a, and then is emitted from the emission surface 27d. These optical elements are positioned so that they are correctly imaged through 28a and rear group lens 28b. And this auxiliary | assistant frame coupling | bond body 30 is inserted from the operation part side in the front-end | tip optical element accommodation hole 14 of the front-end | tip part main body 11, and the front-end | tip part of the inclination board part 23 of the auxiliary | assistant frame 21 is a positioning edge. It is regulated at a position where it contacts 15. Further, after the auxiliary frame combined body 30 is inserted and fixed in the tip optical element housing hole 14, a CCD substrate 29 having a solid-state image pickup device (CCD) 29a at the tip portion is inserted together with the CCD cable 29b, and the solid-state image pickup device is inserted. The image pickup surface 29a is fixed in a state where it matches the image forming position.

  According to the above-described front end structure of the perspective endoscope, the cover lens 20, the prism 27, and the rear group barrel 28 are fixed to the cover lens accommodation hole 22, the prism fixing arm 26, and the rear group barrel, respectively, of the auxiliary frame 21. Since it is bonded and fixed after being accurately positioned with respect to the arm 26a, high positional accuracy can be obtained (in a separate process) and high adhesive strength can be obtained before mounting on the tip body 11.

  In the above embodiment, the auxiliary frame assembly 30 in which the cover lens 20, the prism 27 and the rear group barrel 28 are fixed to the auxiliary frame 21 is inserted into the distal optical element accommodation hole 14 of the distal end body 11 from the operation unit side. In addition, since the position of the auxiliary frame assembly 30 is prevented from falling off because the position is regulated at the position where it abuts against the retaining positioning edge 15, the auxiliary frame assembly 30 can be prevented from falling off. A mode in which the frame combined body 30 is inserted and bonded and fixed is also possible. The present invention can also be applied to a perspective general endoscope that does not include the ultrasonic probe 12.

DESCRIPTION OF SYMBOLS 1 Insertion part 11 Tip part main body 13 Tip slope 14 Tip optical element accommodation hole 15 Stopping positioning edge 20 Cover lens 21 Auxiliary frame 22 Cover lens accommodation hole 23 Inclined plate part 24 Optical path hole 25 Air layer formation recessed part 26 Prism fixed arm 26a Rear group Lens barrel fixing arm 27 Prism 27a Incident (inner surface reflection) surface 27b Both side surfaces 27c Total reflection surface 27d Outgoing surface 28 Rear group lens barrel 28a Aperture 28b Rear group lens 29 CCD substrate 29a Solid-state image sensor 29b CCD cable

Claims (4)

In the distal end structure of the perspective type endoscope in which the cover lens is located on the distal end slope formed in the distal end body of the insertion portion, and the prism and the rear group barrel are located behind the cover lens,
A cover lens housing hole for housing and fixing the cover lens, a prism fixing arm for fixing the prism, and an auxiliary frame integrally including a rear group barrel fixing arm for fixing the rear group barrel,
A distal end structure of an endoscope, characterized in that an auxiliary frame combined body in which the cover lens, the prism and the rear lens barrel are fixed is accommodated in a distal optical element accommodation hole formed in the distal end main body. The endoscope distal end structure according to claim 1, wherein the prism fixing arm and the rear group barrel fixing arm are formed by the same pair of arms. The distal end structure of the endoscope according to claim 1 or 2, wherein the distal end optical element storage hole of the distal end portion main body is formed so that the auxiliary frame combined body can be inserted from the operation portion side. Is a distal end structure of an endoscope in which a retaining positioning edge is formed at the distal end of the storage hole. The distal end structure of an endoscope according to claim 2 or 3, wherein the auxiliary frame includes an inclined plate portion having the cover lens accommodation hole that is flush with a distal end inclined surface of the distal end portion main body, and the inclined plate portion. A pair of arms extending in parallel, and the prism is bonded to the auxiliary frame at a contact portion with the pair of arms and a contact portion with the inclined plate portion, and the rear group barrel is at the rear portion of the prism. An endoscope distal end structure bonded to the pair of arms.

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