JP2018120005A - Objective lens unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an objective lens unit which can precisely define the distance between the surfaces of the lenses of an optical system by a simple configuration.SOLUTION: An objective lens unit 32 includes: a first lens 50 at the front edge of an observation optical system 45; a second lens 51 at the base edge of the observation optical system 45; a fixed frame 46 having a top edge part in which the first lens 50 is fit and having a base edge part in which the second lens 51 is fit; and a spacer 52 made of an optical member, the optical member having a circumscribed circle diameter which can move in parallel to the direction intersecting with the optical axis O of the observation optical system 45 in the fixed frame 46 and the spacer defining the distance between the surfaces of the first lens 50 and the second lens 51 by being brought into contact with the base edge surface of the first lens 50 and the front edge surface of the second lens 51.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a small objective lens unit disposed at a distal end portion of an endoscope.

  Conventionally, endoscopes are used in the medical field, the industrial field, and the like. As the endoscope, there is a so-called electronic endoscope in which an imaging device for acquiring an endoscope image is built in a distal end portion of an insertion portion. In an electronic endoscope used in the medical field, it is desired to reduce the diameter of the insertion portion in order to reduce pain when inserted into the body. In particular, in an endoscope for renal pelvis and urology, an endoscope for bronchi, an endoscope for otolaryngology, etc., it is desirable that the outer diameter of the insertion portion is an extremely small diameter of several millimeters or less.

  As an objective lens unit used at the distal end portion of such an ultrafine endoscope, for example, Patent Document 1 discloses a first holding hole and a second holding hole having a smaller diameter than the first holding hole. And a third holding hole having a diameter larger than that of the second holding hole, and a lens frame provided in this order from the front end side, and the first diaphragm member and the second holding hole in the first holding hole of the lens frame The first lens is disposed from the distal end opening, the spacer block and the second lens are disposed from the proximal opening in the second holding hole, and the second aperture member and the third lens are disposed in the third holding hole. An objective lens unit having a lens is disclosed. In the technique of this Patent Document 1, the second lens is brought into contact with the first lens through the first diaphragm member and the spacer block, and further, the third lens is brought into contact with the second lens through the second diaphragm member. By abutting these lenses, it is possible to position each lens in the optical axis direction without providing an inward flange or the like on an extremely small lens frame.

JP 2013-190488 A

  However, as in the technique disclosed in Patent Document 1 described above, an extremely small objective lens unit has a problem in that when an optical member such as each lens is processed, burrs are easily generated at the edge of the optical member. Such burrs are particularly noticeable when processing an optical member having an outer diameter of 1 mm or less. And when a burr | flash generate | occur | produces in an optical member, the insertion property at the time of inserting the said optical member in a holding hole will be inhibited, and there exists a possibility that it may become difficult to prescribe | regulate the surface of each optical member accurately.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an objective lens unit that can accurately define the inter-surface distance of each lens in an optical system with a simple configuration.

  An objective lens unit according to an aspect of the present invention includes a first lens group including one or more lenses disposed at a distal end of an observation optical system, and one or two or more disposed at a proximal end of the observation optical system. A second lens group composed of the above-mentioned lenses, a fixed frame in which the first lens group is fitted on the distal end side, and the second lens group is fitted on the proximal end side, and in the fixed frame Has a circumscribed circle diameter that can be translated in a direction perpendicular to the optical axis of the optical axis of the observation optical system, and is in contact with the proximal end surface of the first lens group and the distal end surface of the second lens group. And a spacer made of an optical member that defines an inter-surface distance between the first lens group and the second lens group.

  According to the objective lens unit of the present invention, the distance between the surfaces of each lens in the optical system can be accurately defined with a simple configuration.

1 is a schematic configuration diagram of an endoscope system according to an embodiment of the present invention. Same as above, sectional view showing the imaging unit along the optical axis direction Sectional drawing which shows an objective lens unit along an optical axis direction same as the above Same as above, exploded perspective view of the objective lens unit As above, an explanatory diagram showing the relationship between the incident optical path of the objective lens unit and the spacer As above, an explanatory diagram showing the relationship between the incident optical path of the objective lens unit and the spacer Same as above, explanatory drawing when processing the holding hole in the holding frame Same as above, cross-sectional view of the surface-treated holding frame Sectional drawing which shows an objective lens unit along an optical axis direction concerning a 1st modification. Sectional drawing which shows an objective lens unit along an optical axis direction according to a 2nd modification. An exploded perspective view of the objective lens unit according to the third modification. Same as above, a cross-sectional view showing the objective lens unit along the direction perpendicular to the optical axis

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to an embodiment of the present invention, FIG. 1 is a schematic configuration diagram of an endoscope system, FIG. 2 is a cross-sectional view showing an imaging unit along the optical axis direction, and FIG. 3 is an objective lens unit along the optical axis direction. 4 is an exploded perspective view of the objective lens unit, FIGS. 5 and 6 are explanatory views showing the relationship between the incident optical path of the objective lens unit and the spacer, and FIG. 7 is when the holding hole is processed in the holding frame. FIG. 8 is a cross-sectional view of the holding frame subjected to surface treatment.

  An endoscope system 1 shown in FIG. 1 includes an endoscope 2, a light source device 3, a video processor 4, and a display device 5.

  The endoscope 2 includes an insertion portion 11, an operation portion 12 that is connected to the proximal end side of the insertion portion 11, and a universal cable 13 that extends from the operation portion 12. Here, the endoscope 2 of the present embodiment is, for example, an endoscope for a renal pelvis / urinary organ, and therefore, the outer diameter of the insertion portion 11 is formed to be an extremely small diameter of about several millimeters.

  The insertion portion 11 is elongated and flexible, and is connected to the distal end side of the operation portion 12. The insertion portion 11 includes a distal end portion 21, a bending portion 22 connected to the proximal end side of the distal end portion 21, and a flexible tube portion formed of an elongated and long tubular member connected to the proximal end side of the bending portion 22. 23.

  The distal end portion 21 is formed by a hard member provided at the forefront of the insertion portion 11, and a structure such as an imaging unit 30 described later is accommodated therein. In addition, a front end opening of a treatment instrument insertion channel (not shown) that is inserted and arranged in the insertion portion 11 is provided on the front surface of the distal end portion 21.

  The bending portion 22 is configured to include a bi-directional bending mechanism that receives a predetermined operation from the operation portion 12 and bends in, for example, two vertical directions.

  The operation unit 12 includes a grasping unit 24, a bending operation lever 25, a treatment instrument insertion port 26 communicating with a treatment instrument insertion channel (not shown), and a bend preventing part 27. .

  The grip portion 24 is configured by an exterior member that can be gripped by a user or the like, and includes a space for incorporating various structures therein.

  The bending operation lever 25 is provided on the proximal end side of the operation unit 12. The bending operation lever 25 is operated, for example, in a preset upward direction (U direction) or downward direction (D direction) with respect to the neutral position shown in FIG. It is possible to bend in the direction.

  The universal cable 13 is configured by a composite cable through which various signal cables, light guide cables, and the like inserted through the insertion unit 11 and the operation unit 12 are inserted. A light source connector 14 that is detachably connected to the light source device 3 is provided at the extending end of the universal cable 13.

  A signal cable 15 extends from the light source connector 14, and a signal connector 16 that is detachably connected to the video processor 4 is provided at the extended end of the signal cable 15. Yes.

  The light source device 3 includes a light source for supplying illumination light to the endoscope 2.

  The video processor 4 includes drive control of the imaging unit 30 and the like in the endoscope 2 and functions as a control processing unit including a control circuit that controls each component of the endoscope system 1 in an integrated manner. It functions as a signal processing unit that receives the video signal acquired by the 30 and performs predetermined video signal processing or the like.

  The display device 5 receives an image signal acquired by the imaging unit 30 and processed by the video processor 4, and displays an image of an affected area in the body cavity. The vertical direction and the like of the bending portion 22 described above are defined in association with the vertical direction of the image displayed on the display device 5.

  Next, the configuration of the imaging unit 30 disposed at the distal end portion 21 of the endoscope 2 will be described with reference to FIG.

  As shown in FIG. 2, the imaging unit 30 of the present embodiment is configured to include an imaging element unit 31 and an objective lens unit 32 that is connected to the distal end side of the imaging element unit 31.

  The image pickup device unit 31 is fixed to the base end face of the first cover glass 36 by bonding to the image pickup frame 35 having a substantially cylindrical shape, the first cover glass 36 held on the inner periphery on the base end side of the image pickup frame 35. The second cover glass 37 and the image sensor 38 held by the image pickup frame 35 via the first and second cover glasses 36 and 37 are provided. An exterior frame 40 is fitted to the outer periphery of the base end side of the imaging frame 35, and the imaging frame 38 and a circuit board (not shown) that is electrically connected to the imaging element 38 are protected by the exterior frame 40. .

  As shown in FIGS. 2 to 4, the objective lens unit 32 includes an observation optical system 45 and a fixed frame 46 that holds the observation optical system 45.

  The observation optical system 45 includes a first lens 50 composed of a plano-concave lens disposed at the distal end, a second lens 51 composed of a plano-convex lens disposed at the proximal end, a base end surface of the first lens 50 and a first end surface. And a spacer 52 made of a substantially cylindrical infrared cut filter (optical member) that is in contact with the front end surface of the second lens 51.

  That is, since the observation optical system 45 of the present embodiment is disposed at the very small tip portion 21, only by the optical power of the two lenses (first and second lenses 50 and 51). The main part is composed of a simple optical system that forms a subject image.

  Furthermore, the observation optical system 45 of the present embodiment includes a first diaphragm member 53 having a donut disk shape interposed between the first lens 50 and the spacer 52, a second lens 51, and the spacer 52. And a second diaphragm member 54 having a donut disk shape interposed between the two.

  That is, in the present embodiment, the base end surface of the first lens 50 is brought into contact with the spacer 52 via the first diaphragm member 53, and the distal end surface of the second lens 51 is interposed via the second diaphragm member 54. It abuts on the spacer 52. Here, in the present embodiment, the first diaphragm member 53 mainly has a function for preventing the occurrence of flare, and the second diaphragm member 54 mainly has a function for adjusting the brightness.

Note that each optical member constituting the observation optical system 45 of the present embodiment has an outer dimension (diameter) of 1 mm or less. Specifically, among the optical members, for example, the outer diameter dimension φ ₁₁ of the first lens 50 and the first diaphragm member 53 is set to 0.9 mm. In addition, the outer diameter dimension φ _l2 of the second lens 51 and the second diaphragm member 54 is set to 0.55 mm, which is smaller than the first lens 50 and the first diaphragm member 53. Further, the outer dimension (circumscribed circle diameter) φ _{f0 of} the spacer 52 is set to 0.5 mm, which is smaller than the second lens 51 and the second diaphragm member 54.

  The fixed frame 46 is configured by a stepped substantially cylindrical member having step portions on the outer peripheral portion and the inner peripheral portion.

  More specifically, the fixed frame 46 is formed by cutting a columnar material made of, for example, stainless steel, and a clamp claw 70 of a cutting machine is provided on the outer periphery on the front end side of the fixed frame 46. A large-diameter portion 60 that can be clamped by (see FIG. 7) or the like is formed. In addition, a narrow-diameter portion 61 that can be fitted to the inner periphery on the distal end side of the imaging frame 35 is formed on the outer periphery on the proximal end side of the fixed frame 46.

  On the other hand, a stepped through hole 62 that penetrates from the distal end surface to the proximal end surface along the direction of the optical axis O is provided inside the fixed frame 46. The through-hole 62 has a first fitting hole 63 having an inner diameter dimension into which the first lens 50 can be fitted, and a second fitting hole having an inner diameter dimension into which the second lens 51 can be fitted. The part 64 is formed by being connected back and forth along the optical axis O direction. That is, the first and second fitting hole parts 63 and 64 are both straight holes, and the inner diameter dimension of the second fitting hole part 64 is smaller than the inner diameter dimension of the first fitting hole part 63. Is set.

The fixed frame 46 of the present embodiment, for example, external dimensions phi _b of the large-diameter portion 60 is 1.1 mm in the optical axis direction length L is set to 1.1 mm.

  In this case, the through hole 62 of the present embodiment is formed by only the first fitting hole 63 and the second fitting hole 64 which are two holes having different inner diameters. It is possible to process from the same direction by a single clamp on the material of the frame 46. That is, for example, as shown in FIG. 7, when the through hole 62 is processed, the material 46 a of the fixed frame 46 is set in the cutting machine by the large diameter portion 60 being clamped by the clamp claws 70. Then, in a state where the material 46 a of the fixed frame 46 is rotated around the optical axis O integrally with the clamp claw 70, the first fitting hole 63 and the second fitting portion 63 are inserted by the blade 71 inserted from the distal end side. The fitting hole 64 can be processed. Therefore, there is no need to re-clamp the material 46a of the minute fixing frame 46 separately when the first fitting hole 63 is processed and when the second fitting hole 64 is processed. It is possible to maintain the coaxiality of the fitting hole portions 63 and 64 with high accuracy.

  In the first fitting hole 63 of the fixed frame 46 formed in this way, the first lens 50 is fitted and held from the front end side together with the first diaphragm member 53.

  Here, since the first lens 50 is a portion exposed to the outside from the end face of the distal end portion 21 of the insertion portion 11, the first lens 50 is prevented from falling off from the distal end portion 21 even when the endoscope 2 is sterilized at a high temperature. There is a need to. For this reason, it is desirable that the first lens 50 be fixed to the first fitting hole 63 via the heat-resistant solder joint 66.

  When performing such solder joining, for example, as shown in FIG. 8, the inner peripheral surface of the first fitting hole 63 and the first sightseeing hole 63 and the second fitting hole 64. Surface treatment is performed to facilitate the adhesion of solder to the step formed between the two. Specifically, "Ep-Fe / Ni, Au" or "SSP-Fe / Cr," is provided on the inner peripheral surface of the first fitting hole 63 and the stepped portion with the second fitting hole 64. A thin film 66a such as “Ni, Au” is formed by sputtering or the like. Thereafter, the first diaphragm member 53 and the first lens 50 are fitted into the first fitting hole 63. Further, in a state where the fixed frame 46 is erected with the distal end side up, a solder ring is disposed on the distal end side of the first fitting hole 63 and the first lens 50. Then, the solder ring arranged in this way is melted in the furnace and flows into the fitting portion between the first fitting hole 63 and the first lens 50, whereby the first lens 50 has the first lens 50. It is firmly fixed to the fitting hole 63.

  On the other hand, after the spacer 52 is inserted from the base end side into the second fitting hole portion 64 of the fixed frame 46, the second lens 51 is inserted from the base end side together with the second diaphragm member 54, Is retained.

  Thus, the spacer 52 is disposed in the fixed frame 46 (in the second fitting hole 64) in a state in which the spacer 52 can be translated in the direction perpendicular to the optical axis O of the observation optical system 45. The spacer 52 is in contact with the proximal end surface of the first lens 50 through the first diaphragm member 53 and the proximal end surface of the spacer 52 through the second diaphragm member 54. The distance between the surfaces along the optical axis O direction between the first lens 50 and the second lens 51 is defined.

In this case, the dimensions of each part of the objective lens unit 32 are as follows: the opening diameter of the first diaphragm member 53 is φ _s1 , the circumscribed circle diameter of the spacer 52 is φ _f0 , the effective diameter of the end face of the spacer 52 is φ _f1 , and the fixed frame the second inner diameter of the fitting hole portion 64 when the phi _a, is set to satisfy the following equation (1) relation is a site where the spacers 52 are arranged at 46.

In the objective lens unit 32 shown in FIG. 3, since the effective diameter φ _f1 of the end face of the spacer 52 is equal to the circumscribed circle diameter φ _f0 , the above-described equation (1) becomes the following equation (2).

  Then, by defining the relative dimensions of each part of the objective lens unit 32 as described above, for example, as shown in FIGS. 5 and 6, the axis of the optical axis O in the second fitting hole 64. Even when the spacer 52 is translated to any position in the perpendicular direction, all of the light beams that have passed through the first lens 50 and the first diaphragm member 53 can be incident on the spacer 52. That is, it is possible to set so that the light incident on the image sensor 38 passes through the spacer 52 having a function as an infrared cut filter without leakage.

  As a countermeasure against stray light, it is preferable to perform a so-called black treatment using chromium vapor deposition or the like on the inner peripheral surface of the second fitting hole 64, but in the present embodiment, an increase in thickness due to chromium vapor deposition or the like. In order to prevent this, the black processing is omitted.

  According to such an embodiment, the first lens 50 disposed at the distal end of the observation optical system 45, the second lens 51 disposed at the proximal end of the observation optical system 45, and the first lens on the distal end side. And a fixed frame 46 in which the second lens 51 is fitted on the proximal end side, and a parallel movement in the direction perpendicular to the optical axis O of the observation optical system 45 within the fixed frame 46. It has a possible circumscribed circle diameter, and is in contact with the proximal end surface of the first lens 50 and the distal end surface of the second lens 51 to define the inter-surface distance between the first lens 50 and the second lens 51. With the spacer 52 made of the optical member, the distance between the surfaces of the first and second lenses 50 and 51 in the observation optical system 45 can be accurately defined with a simple configuration.

  That is, an extremely small spacer 52 in which it is difficult to suppress the generation of burrs during processing by inserting the spacer 52 into the fixed frame 46 with a predetermined clearance secured to the fixed frame 46. Even when the distance between the surfaces of the first lens 50 and the second lens 51 is defined using the spacer 52, the spacer 52 can be inserted into the fixed frame 46 without hindering the insertion property by the burr. The distance between the surfaces of the first and second lenses 50 and 51 can be defined with high accuracy.

  In this case, even when a clearance is provided between the fixed frame 46 and the spacer 52 by the relative dimensions of the respective parts of the objective lens unit 32 satisfying the relationship shown in the above equation (1), imaging is performed. It can be set so that the light incident on the element 38 passes through the spacer 52, which is an optical member, without leakage. Therefore, it is possible to accurately define the distance between the surfaces of the first and second lenses 50 and 51 while ensuring the insertability of the spacer 52 without changing the optical performance of the observation optical system 45 in the objective lens unit 32. it can.

Here, for example, as shown in FIG. 9, it is possible to chamfer both ends of the spacer 52. In this case, by setting the circumscribed circle diameter φ _f0 of the spacer 52 and the effective diameter φ _f1 of the end face of the spacer 52 so as to satisfy the relationship of the above formula (1), the same as in the above embodiment There is an effect.

  Further, for example, as shown in FIG. 10, the first and second diaphragm members 53 and 54 can be integrally formed with the first and second lenses 50 and 51 by vapor deposition, printing, or the like.

  Further, for example, as shown in FIGS. 10 to 12, the shape of the spacer 52 may be a polygonal column shape such as a square column instead of the columnar shape.

  Thus, by making the spacer 52 into a polygonal column shape, the processing of the spacer 52 becomes easy. In particular, by using a quadrangular prism shape, the processing of the spacer 52, which is a minute optical member, becomes extremely easy, and the generation of burrs and the like can be effectively suppressed.

  In addition, this invention is not limited to each embodiment described above, A various deformation | transformation and change are possible, and they are also in the technical scope of this invention.

  For example, in the above-described embodiments and the like, an example in which the objective lens unit is applied to an endoscope for a renal pelvis / urinary organ has been described, but the present invention is not limited to this, and for example, an endoscope for bronchi Of course, the present invention can be applied to a mirror or other endoscopes such as an otolaryngological endoscope.

  In the above-described embodiment, the first lens group including two or more lenses is used instead of the first lens 50 and the second lens 51 arranged on the distal end side and the proximal end side of the observation optical system. It is also possible to arrange the second lens group. That is, according to the present invention, the inter-surface distance between the first lens group in the broad sense consisting of one or more lenses and the second lens group in the broad sense consisting of one or more lenses is small. The present invention can be applied to an objective lens unit defined through a spacer.

  Moreover, for example, it is needless to say that the configurations of the above-described embodiment and each modification may be combined as appropriate.

DESCRIPTION OF SYMBOLS 1 ... Endoscope system 2 ... Endoscope 3 ... Light source apparatus 4 ... Video processor 5 ... Display apparatus 11 ... Insertion part 12 ... Operation part 13 ... Universal cable 14 ... Light source connector 15 ... Signal cable 16 ... Signal connector 21 ... distal end 22 ... bending part 23 ... flexible tube part 24 ... gripping part 25 ... bending operation lever 26 ... treatment instrument insertion port 27 ... folding part 30 ... imaging unit 31 ... imaging element unit 32 ... objective lens unit 35 ... imaging Frame 36 ... First cover glass 37 ... Second cover glass 38 ... Image sensor 40 ... Exterior frame 45 ... Observation optical system 46 ... Fixed frame 46a ... Fixed frame material 50 ... First lens (first lens group) )
51 ... 2nd lens (2nd lens group)
52 ... Spacer 53 ... First throttle member 54 ... Second throttle member 60 ... Large diameter part 61 ... Small diameter part 62 ... Through hole 63 ... First fitting hole part 64 ... Second fitting hole part 66 ... Solder joint 66a ... Thin film 70 ... Clamp claw 71 ... Blade O ... Optical axis

Claims (6)

A first lens group consisting of one or more lenses arranged at the tip of the observation optical system;
A second lens group consisting of one or more lenses disposed at the base end of the observation optical system;
A fixed frame in which the first lens group is fitted on the distal end side and the second lens group is fitted on the proximal end side;
A circumscribed circle diameter that is movable in a direction perpendicular to the axis of the optical axis of the observation optical system within the fixed frame, and is provided between a proximal end surface of the first lens group and a distal end surface of the second lens group. An objective lens unit comprising: a spacer made of an optical member that is in contact with the first lens group and defines a distance between the surfaces of the second lens group. A first diaphragm member interposed between the first lens group and the spacer;
The opening diameter of the first diaphragm member is φ _s1 , the circumscribed circle diameter of the spacer is φ _f0 , the effective diameter of the end face of the spacer is φ _f1 , and the inner diameter of the portion where the spacer is disposed in the fixed frame is φ If it is _a,
[(Φ _f1 / 2) − {(φ _a1 −φ _f0 ) / 2}] − (φ _s / 2)> 0
The objective lens unit according to claim 1, wherein the relationship is established. The fixed frame communicates from a distal end side to a first fitting hole portion into which the first lens group is fitted, and a proximal end side of the first fitting hole portion. A second fitting hole having a smaller diameter than the first fitting hole into which the two lens groups are fitted;
The said spacer has the said circumscribed circle diameter smaller than the internal diameter of the said 2nd fitting hole part, and is arrange | positioned inside the said 2nd fitting hole part. Objective lens unit. A first diaphragm member interposed between the first lens group and the spacer;
The objective lens unit according to claim 1, further comprising: a second diaphragm member interposed between the second lens group and the spacer.   The objective lens unit according to claim 1, wherein the spacer is an infrared cut filter.   The objective lens unit according to claim 1, wherein the spacer has a polygonal column shape.

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