JP5877118B2 - Front end structure of perspective endoscope - Google Patents

Description

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

12 and 13 show a conventional example of a perspective endoscope.
A tip optical element accommodation hole 014 extending in the axial direction of the hard tip portion 012 is formed on the inclined surface 013 provided in the hard tip portion 012 of the insertion portion 011 of the perspective endoscope 010. The tip optical element An optical element combination including a rear group barrel 015, a rear group lens 016, an auxiliary frame 017, a cover lens 020, and a prism 022 is inserted into the storage hole 014.
A rear group lens 016 composed of a plurality of lenses can be fixed inside the rear group barrel 015.
The front portion of the auxiliary frame 017 forms an inclined plate portion 018 in a direction parallel to the inclined surface 013. A cover lens housing hole 019 to which the cover lens 020 can be fixed is formed on the front surface of the inclined plate portion 018. Further, a pair of left and right prism fixing arms 021 extending rearward are integrally projected at the rear portion of the auxiliary frame 017, and the prism 022 can be supported between the pair of prism fixing arms 021.

The assembly operation of the optical element combination is performed outside the perspective endoscope 010 (tip optical element accommodation hole 014).
Specifically, first, the rear group lens 016 inserted into the rear group lens barrel 015 is bonded and fixed to the rear group lens barrel 015, and at the same time as this operation, the prism is fixed by the pair of prism fixing arms 021 of the auxiliary frame 017. Then, the prism fixing arm 021 and the prism 022 are bonded and fixed. Next, the front portion of the rear group barrel 015 is clamped by the pair of prism fixing arms 021, and the pair of prism fixing arms 021 and the rear group barrel 015 are bonded and fixed while holding the clamped state with a jig. Finally, the cover lens 020 is fitted into the cover lens accommodation hole 019 of the auxiliary frame 017, and the cover lens accommodation hole 019 and the cover lens 020 are bonded and fixed.
The optical element assembly thus completed is inserted into the front optical element accommodation hole 014 from the rear end opening (not shown) of the front optical element accommodation hole 014, and the cover lens 020 is exposed at the inclined surface 013 in the state where the front end is exposed. Fix to the optical element storage hole 014.

An imaging element 023 located immediately after the rear lens barrel 015 is fixed to the front optical element accommodation hole 014.
Incident light (observation image) that has entered the cover lens 020 is incident from the incident plane 022a of the prism 022, is reflected twice by the total reflection plane 022b and the inner surface of the incident plane 022a, and then exits from the exit plane 022c. After passing through 016, an image is formed on the imaging surface of the image sensor 023, and the image is captured by the image sensor 023.

JP 2011-115486 A

The prism 022 of the optical element combination body is covered with a prism fixing arm 021 as shown in the drawing, but the other parts are exposed.
Therefore, when the rear group barrel 015 and the auxiliary frame 017 are fixed while forming a gap between the front end surface of the rear group barrel 015 and the emission plane 022c as shown in the drawing, each prism fixing arm 021 and the rear group mirror are fixed. Before the adhesive applied between the cylinders 015 solidifies, it may adhere to the emission plane 022c and solidify as it is.
If the adhesive is solidified on the emission plane 022c, emission of light (observation image) from the emission plane 022c to the rear lens group 016 is hindered by the adhesive.

Further, as described above, in order to assemble the optical element combination, <1> an operation of bonding and fixing the rear group lens barrel 015 and the rear group lens 016, an operation of bonding and fixing the prism 022 to the auxiliary frame 017, <2> a step of bonding and fixing the rear lens barrel 015 and the auxiliary frame 017 using a jig; and <3> a step of finally bonding and fixing the cover lens 020 to the auxiliary frame 017. Is required. Therefore, it takes a long time to complete the optical element combination.
If the cover lens 020 is bonded and fixed to the auxiliary frame 017 in the step <1>, the assembly of the optical element assembly can be realized in two steps. However, in this case, the cover lens 020 may be damaged by the jig in the step of bonding and fixing the rear lens barrel 015 and the auxiliary frame 017 using the jig.

  The present invention can reduce the possibility that an adhesive for adhering the auxiliary frame that supports the cover lens and the prism and the rear group lens barrel that supports the rear group lens will adhere to the emission plane of the prism, and the cover lens. It is an object of the present invention to provide a distal-end structure of a perspective endoscope that can be assembled in a short time without damaging the endoscope.

  In the distal end structure of the perspective endoscope according to the present invention, a distal end optical element accommodation hole extending in the axial direction of the distal end hard portion is formed on an inclined surface provided in the distal end hard portion of the insertion portion, and the distal end optical element accommodation hole is formed. In the distal end structure of the perspective type endoscope in which the optical element is housed, the rear group lens barrel inserted into the distal optical element housing hole and having both ends opened, and the rear group lens supported inside the rear group lens barrel And a pair of prism fixing arms that are inserted in the front optical element housing hole so as to be positioned in front of the rear lens barrel, have a cover lens housing hole on the front surface, and extend rearward at the rear portion. A frame, a cover lens fitted and fixed in the cover lens housing hole, and a prism sandwiched between a pair of prism fixing arms, and the auxiliary frame is fitted into the front end opening of the rear group barrel from the front. And with respect to the inner peripheral surface of the front end opening It is characterized in that it comprises a fitting projection which an adhesive is applied to wear.

  The cross-sectional shape of the rear group barrel is a quadrangle, the outer peripheral surface of the fitting projection is opposed to the four surfaces constituting the inner peripheral surface of the front end opening of the rear group barrel, and the adhesive You may provide four surfaces which apply | coated.

  The rear group barrel is connected to a lens support cylinder that supports the rear group lens, and a rear end portion of the rear group barrel is connected to a front end opening of the lens support cylinder, and the fitting projection And an intermediate connecting tube into which the portion is fitted.

In the present invention, the auxiliary frame includes a fitting protrusion that is fitted from the front to the front end opening of the rear lens barrel, and the adhesive applied to the fitting protrusion is applied to the inner peripheral surface of the front end opening. It is attached.
Therefore, before the adhesive is solidified, there is little possibility that the adhesive flows from the inner peripheral surface of the front end opening of the rear lens barrel and the fitting protrusion to the prism side and solidifies on the emission plane of the prism. Therefore, there is a low possibility that the progress of light (observation image) emitted from the emission plane of the prism to the rear lens group is hindered by the adhesive.

Further, the optical element combination including the auxiliary frame, the cover lens, the prism, the rear group lens barrel, and the rear group lens is <1> the cover lens and the prism are fixed to the auxiliary frame, and the rear group lens is set to the rear group lens barrel. It is possible to assemble in a short time because it is completed by the two steps of the step of <2> and the step of fixing the auxiliary frame to the rear group barrel.
In addition, since the auxiliary frame and the rear group lens barrel are bonded and fixed while the fitting protrusion of the auxiliary frame is fitted to the front end opening of the rear group lens barrel, a jig is used for bonding and fixing the auxiliary frame and the rear group lens barrel. Need not be used. Therefore, even if the auxiliary frame to which the cover lens (and the prism) is fixed and the rear group lens barrel to which the rear group lens is fixed are connected, the cover lens is not damaged (by the jig).

1 is an external view showing an embodiment of an ultrasonic endoscope to which the present invention is applied. It is an expansion vertical side view of a tip hard part. It is the perspective view seen from the front of an auxiliary | assistant frame. It is the perspective view seen from the diagonally upper back of the auxiliary frame. It is the perspective view seen from the lower diagonal back of the auxiliary frame. It is a rear view of an auxiliary frame. It is the perspective view seen from the front of the middle connection cylinder. It is the perspective view seen from the front of a rear group unit. (A) is a side view of the lens prism unit in a separated state, and (b) is a side view of the rear group unit in a separated state. It is a side view of the separation state of a lens prism unit, an intermediate connection cylinder, and a rear group unit. It is a side view of the completion state of an optical element combination body. It is an expansion vertical side view similar to FIG. 2 of the endoscope of a prior art example. It is the perspective view seen from the front of the auxiliary frame of a prior art example.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The front-rear direction, the up-down direction, and the left-right direction in the following description are based on the arrow direction in the figure.
An ultrasonic endoscope 10 shown in FIG. 1 includes an operation unit 11, an insertion unit 12 extending forward from the operation unit 11, a universal tube 13 extending from the operation unit 11 to the opposite side of the insertion unit 12, and ultrasonic image transmission. And a tube 14 for a perspective view. The ultrasonic image transmission tube 14 is connected to an ultrasonic diagnostic apparatus (not shown), and the universal tube 13 is connected to a processor (image processing apparatus / light source apparatus, not shown). The processor and the processor are both connected to a CRT monitor (not shown).
The insertion portion 12 is formed with a bending portion 17 that bends in the vertical and horizontal directions according to the rotation operation of the bending operation lever 15 provided in the operation portion 11. The flexible tube portion 18 is curved by a direct operation of the surgeon.
As shown in FIG. 1, the distal end portion of the insertion portion 12 with respect to the bending portion 17 is a hard end portion 19 made of hard resin. An inclined surface 20 is formed in the latter half of the distal end hard portion 19, and a cover lens 40, an illumination lens, and the like are provided on the inclined surface 20. An ultrasonic probe 19 a located immediately before the inclined surface 20 is formed in the front half of the distal end hard portion 19.

The inclined optical surface 20 of the distal end hard portion 19 is provided with a distal end optical element accommodation hole 21 that penetrates the distal end rigid portion 19 in the axial direction thereof. As shown in FIG. 2, a retaining positioning edge 22 is formed at the distal end portion of the distal optical element housing hole 21 so as to protrude inward.
The front optical element housing hole 21 includes an auxiliary frame 27, a prism 34, a cover lens 40, a rear group barrel 42 (intermediate connection cylinder 44, lens support cylinder 47), an annular spacer 51, and a rear group lens 52 combination. The optical element combined body 25 is inserted from the rear end opening (not shown) of the front end optical element storage hole 21.
The metal auxiliary frame 27 has a substantially square inclined plate portion 28 that is inclined in the same direction as the inclined surface 20. The inclined plate portion 28 is formed with a cover lens housing hole 29 (counterbore hole) and an optical path hole 30, and an air layer forming concave portion 31 located above the optical path hole 30 is formed on the back surface of the inclined plate portion 28. It is recessed. The rear half of the inclined plate portion 28 constitutes a fitting protrusion 32 having a smaller cross-sectional shape than the front half. The cross-sectional shape of the fitting protrusion 32 is substantially square, and includes four planes, that is, an upper plane 32a, a lower plane 32b, a left plane 32c, and a right plane 32d on the upper and lower sides and the left and right sides of the circumferential surface. In addition, a pair of prism fixing arms 33 that are symmetrical with respect to the centers of the cover lens housing hole 29 and the optical path hole 30 and extend rearward while being parallel to each other are integrally formed on the left and right sides of the rear surface of the fitting protrusion 32. Is formed.
The prism 34 has an incident plane 35 (internal reflection surface) that contacts the back surface of the inclined plate portion 28, a pair of side planes 36, a total reflection plane 37, and an output plane 38. The prism 34 is integrated with the auxiliary frame 27 outside the ultrasonic endoscope 10 (tip optical element storage hole 21). That is, the left and right side planes 36 are sandwiched between the inner surfaces of the pair of prism fixing arms 33 in a state where the incident plane 35 is in contact with the back surface of the inclined plate portion 28 (the fitting protrusion 32). 35 and the back surface of the inclined plate portion 28 (the fitting protrusion 32) are bonded and fixed, and the left and right side planes 36 and the left and right prism fixing arms 33 are bonded and fixed.
The cover lens 40 having the same cross-sectional shape as the cover lens housing hole 29 is bonded and fixed to the inner surface of the cover lens housing hole 29 with the back surface thereof in contact with the bottom surface of the cover lens housing hole 29. The bonding and fixing work of the cover lens 40 and the cover lens housing hole 29 is performed after the bonding and fixing work of the auxiliary frame 27 and the prism 34 outside the ultrasonic endoscope 10 (tip optical element housing hole 21). By fixing the prism 34 and the cover lens 40 to the auxiliary frame 27 (simultaneously), the lens prism unit 39 shown in FIG. 10 is completed.

The rear group barrel 42 includes a metal intermediate connection cylinder 44 and a resin lens support cylinder 47.
The intermediate connection cylinder 44 is a cylindrical member having a substantially square cross section, and its axis is parallel to the distal optical element accommodation hole 21. A front portion of the intermediate connection cylinder 44 is inclined with respect to a plane orthogonal to the axis of the intermediate connection cylinder 44, and an inner peripheral edge portion of the front end of the intermediate connection cylinder 44 constitutes an adherend surface 45.
The lens support tube 47 is a cylindrical member having a substantially square cross section, similar to the intermediate connection tube 44, and its axis is parallel to the intermediate connection tube 44. A fitting connection portion 48 having a smaller cross-sectional shape than the rear portion is formed at the front portion of the lens support tube 47. The fitting connection portion 48 has four planes, that is, an upper plane 48a, a lower plane 48b, a left plane 48c, and a right plane 48d. Further, an optical element fixing hole 49 having a circular cross section penetrating the lens support tube 47 in the axial direction is formed inside the lens support tube 47.
In the optical element fixing hole 49, two annular spacers 51 and two rear group lenses 52 are accommodated in a coaxial state where they are alternately arranged. The annular spacer 51 and the rear group lens 52 are arranged in the optical element fixing hole 49. Bonded to the inner surface. The bonding and fixing work of the annular spacer 51 and the rear lens group 52 to the lens support tube 47 (optical element fixing hole 49) is performed on the prism 34 for the auxiliary frame 27 outside the ultrasonic endoscope 10 (tip optical element storage hole 21). Alternatively, it is performed simultaneously with the adhesive fixing work of the cover lens 40. The rear spacer unit 53 illustrated in FIGS. 8 and 10 is completed by fixing the annular spacer 51 and the rear lens group 52 to the lens support tube 47.

The lens prism unit 39, the intermediate connecting cylinder 44, and the rear group unit 53 are integrated outside the ultrasonic endoscope 10 (the distal optical element accommodation hole 21). Specifically, the outer peripheral surface (upper plane 32a, lower plane 32b, left side plane 32c, and right side plane 32d) of the fitting projection 32 of the auxiliary frame 27 of the lens prism unit 39 is applied after applying an adhesive. The mating protrusion 32 is fitted into the front end opening of the intermediate connecting cylinder 44 (facing the upper, lower, left and right sides of the adherend surface 45), and the upper plane 32a, the lower plane 32b and the left side The adhesive applied to each surface of the plane 32c and the right plane 32d is attached to the upper portion, the lower portion, the left portion, and the right portion of the adherend surface 45, respectively. When the lens prism unit 39 and the intermediate connecting cylinder 44 are fixed in this way, the rear surface of the emission plane 38 of the prism 34 comes into contact with the front surface of the front annular spacer 51 (the peripheral portion of the through hole formed in the center). Further, after applying an adhesive to the outer peripheral surface (upper plane 48a, lower plane 48b, left plane 48c, and right plane 48d) of the fitting connection portion 48 of the lens support cylinder 47 of the rear group unit 53, the fitting connection portion. 48 is fitted into the rear end opening of the adherend surface 45 (facing each of the four surfaces constituting the inner peripheral surface of the rear end of the intermediate connecting tube 44), and the upper plane 48a, the lower plane 48b, the left plane The adhesive applied to each surface of 48c and the right side flat surface 48d is adhered to the four surfaces constituting the inner peripheral surface of the rear end of the intermediate connecting cylinder 44. The adhesive fixing work between the lens prism unit 39 and the intermediate connecting cylinder 44 and the adhesive fixing work between the rear group unit 53 and the intermediate connecting cylinder 44 are performed simultaneously.
Then, the above-mentioned adhesive for fixing the lens prism unit 39 and the intermediate connection cylinder 44 and the above-mentioned adhesive for fixing the rear group unit 53 and the intermediate connection cylinder 44 are solidified to complete the optical element combination 25. Is inserted into the inside of the front end optical element storage hole 21 from the rear end opening of the front end optical element storage hole 21, and the front end portion of the inclined plate portion 28 is brought into contact with the rear surface of the retaining positioning edge 22 to be coupled with the optical element. The body 25 is bonded and fixed to the distal optical element accommodation hole 21. Then, as shown in FIG. 2, the front surface of the inclined plate portion 28 is flush with the front surface of the inclined surface 20, and the cover lens 40 is exposed on the front surface of the inclined surface 20.
After the optical element combination 25 is fixed to the front optical element storage hole 21, an image sensor 55 having an image signal cable 56 is inserted into the front optical element storage hole 21 from the rear end opening of the front optical element storage hole 21, and the image sensor. 55 is fixed to the tip optical element accommodation hole 21 in a state of being positioned immediately after the lens support tube 47.

  Incident light (observation image) that enters the cover lens 40 of the ultrasonic endoscope 10 passes through the optical path hole 30 and enters the prism 34 from the incident plane 35, and is incident on the inner surfaces of the total reflection plane 37 and the incident plane 35. After being reflected twice, the light is emitted backward from the emission plane 38, passes through the annular spacer 51 and the rear group lens 52, and then forms an image on the imaging surface of the imaging element 55. Image data picked up by the image pickup device 55 is sent to the processor via the image signal cable 56, and after being subjected to image processing by the processor, displayed on the CRT monitor.

  In the ultrasonic endoscope 10 having the above-described configuration, the fitting protrusion 32 to which the adhesive is applied is fitted into the front end opening of the intermediate connection cylinder 44, and the adhesive is applied to the adherend surface 45 of the intermediate connection cylinder 44. It is a structure that adheres. Therefore, even if there is a gap between the emission plane 38 and the front surface of the front annular spacer 51, the emission of the prism 34 from the fitting protrusion 32 and the adherend surface 45 before the adhesive is solidified. The risk of flowing to the plane 38 side and solidifying on the exit plane 38 is small. Therefore, there is a low possibility that the progress of the light (observation image) emitted from the emission plane 38 of the prism 34 to the rear group lens 52 is hindered by the adhesive.

  Further, the intermediate connecting tube 44 having a substantially square cross section (including the upper plane 32a, the lower plane 32b, the left plane 32c, and the right plane 32d) and the fitting protrusion 32 having a substantially square cross section (including four planes). An intermediate connecting tube that is fitted to the front end portion of the fitting connection portion 48 and has a substantially square cross section (including an upper plane 48a, a lower plane 48b, a left side plane 48c, and a right side plane 48d). 44, the lens prism unit 39, the intermediate connecting cylinder 44, and the rear group unit 53 can be coupled without causing an axial shift. Therefore, the light incident on the cover lens 40 can be reliably imaged on the imaging surface of the imaging element 55.

Further, the optical element combined body 25 is <1> a step of simultaneously assembling the lens prism unit 39 and an assembly operation of the rear group unit 53, <2> an adhesive fixing operation of the lens prism unit 39 and the intermediate connection cylinder 44, and Since it is possible to assemble the optical element combination body 25 in a short time, it is possible to assemble it in two steps, ie, the step of simultaneously bonding and fixing the rear group unit 53 and the intermediate connecting cylinder 44.
Moreover, since the step <2> is performed while fitting the fitting protrusion 32 of the auxiliary frame 27 into the front end opening of the intermediate connection cylinder 44 (rear group lens barrel 42), the process of <2> is performed with assistance. There is no need to use a jig for supporting the frame 27 and the intermediate connection cylinder 44 (the rear group barrel 42). Therefore, the cover lens 40 is not damaged (by the jig) when the auxiliary frame 27 to which the cover lens 40 is fixed and the intermediate connection cylinder 44 (rear group lens barrel 42) are connected.

  In addition, the prism fixing arm 33 of the auxiliary frame 27 of the present embodiment holds only the prism 34 (the rear group barrel rear group barrel 42 is not clamped). Compared to the short dimension. Since the auxiliary frame 27 made of metal is generally manufactured by a shaving process, the auxiliary frame 27 in which the longitudinal length of the prism fixing arm 33 is short is easier to manufacture than the auxiliary frame 017.

As mentioned above, although this invention was demonstrated using the said embodiment, this invention can be implemented, giving various deformation | transformation.
For example, the intermediate connection tube 44 and the lens support tube 47 may be configured as an integrally molded product made of metal or resin without being separated.
Further, the cross-sectional shapes of the fitting protrusion 32 of the auxiliary frame 27, the fitting connection portion 48 of the lens support tube 47, and the inner hole of the intermediate connection tube 44 may not be the above, and are different from the square shape. It is good also as circular shape (for example, pentagon etc.).
Further, the retaining positioning edge 22 may be omitted from the distal end hard portion 19 and the optical element combination 25 may be inserted into the distal end optical element accommodation hole 21 from the front end opening of the distal end optical element accommodation hole 21.
Furthermore, the present invention may be applied to a perspective endoscope that does not include the ultrasonic probe 19a.

10 Ultrasound endoscope (perspective endoscope)
DESCRIPTION OF SYMBOLS 11 Operation part 12 Insertion part 13 Universal tube 14 Ultrasound image transmission tube 15 Bending operation lever 17 Bending part 18 Flexible pipe part 19 Hard tip part 19a Ultrasonic probe 20 Inclined surface 21 Optical element accommodation hole 22 Keeping positioning edge 25 Optical element combined body 27 Auxiliary frame 28 Inclined plate portion 29 Cover lens housing hole 30 Optical path hole 31 Air layer forming recess 32 Fitting protrusion 32a Upper plane 32b Lower plane 32c Left plane 32d Right plane 33 Prism fixed arm 34 Prism 35 Incident Plane 36 Side plane 37 Total reflection plane 38 Exit plane 39 Lens prism unit 40 Cover lens 42 Rear group barrel 44 Intermediate connection cylinder 45 Adhered surface 47 Lens support cylinder 48 Fitting connection portion 48a Upper plane 48b Lower plane 48c Left plane 48d Right side plane 49 Optical element fixing hole 51 Annular spacer 5 Rear Group Lens 53 Rear Group Unit 55 Image Sensor 56 Image Signal Cable 010 Perspective Endoscope 011 Insertion Section 012 Tip Hard Part 013 Inclined Surface 014 Tip Optical Element Storage Hole 015 Rear Group Lens Tube 016 Rear Group Lens 017 Auxiliary Frame 018 Inclined plate portion 019 Cover lens accommodation hole 020 Cover lens 021 Prism fixing arm 022 Prism 022a Incident plane 022b Total reflection plane 022c Output plane 023 Imaging element

Claims (3)

A distal end portion of a perspective endoscope in which a distal end optical element accommodation hole extending in the axial direction of the distal end hard portion is formed on an inclined surface provided in the distal end hard portion of the insertion portion, and the optical element is accommodated in the distal end optical element accommodation hole In structure
A rear group barrel inserted into the tip optical element storage hole and having both ends open;
A rear group lens supported inside the rear group barrel;
An auxiliary frame provided with a pair of prism fixing arms at the front and extending rearward at the rear part, the front lens element having a cover lens accommodation hole inserted in the front optical element accommodation hole in front of the rear group barrel; ,
A cover lens fitted and fixed in the cover lens housing hole;
A prism sandwiched between a pair of prism fixing arms,
With
The auxiliary frame includes a fitting protrusion that is fitted from the front to the front end opening of the rear group barrel and is coated with an adhesive that adheres to the inner peripheral surface of the front end opening. Front end structure of a perspective endoscope. In the front-end | tip part structure of the perspective type endoscope of Claim 1,
The cross-sectional shape of the rear group barrel is a quadrangle,
A perspective endoscope having four surfaces on which the outer peripheral surface of the fitting projection is opposed to the four surfaces constituting the inner peripheral surface of the front end opening of the rear group lens barrel and the adhesive is applied. Tip structure. In the front-end | tip part structure of the perspective type endoscope of Claim 1 or 2,
A lens support tube for supporting the rear lens group;
An intermediate connecting cylinder in which the rear end portion of the lens is connected to the front end opening of the lens support tube, and the fitting protrusion is fitted to the front end opening of the lens supporting tube;
The tip part structure of a perspective type endoscope provided with this.

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