JP2015047358A - Lens unit, and endoscope including lens unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens unit which can prevent cloudiness of a spherical segment part of an objective lens, can downsize a tip side, and has excellent assemblability to an endoscope.SOLUTION: A lens unit includes an objective lens 15 in which a tip face 15s and an outer circumferential face 15g are exposed and which is formed with an abutment face 15t on an inner side rather than a base end face 15k and on the tip face 15s side rather than the base end face 15k, a spherical segment part 15q is formed at the center of the abutment face 15t, and an inner circumferential face 15n is formed between the abutment face 15t and the base end face 15k. A lens frame 20 has: a diameter expansion part 22 positioned apart in the rear of the base end face 15k; and a fitting part 21 into the objective lens 15, which projects in front of the diameter expansion part 22. The base end face 15k is fixed to a tip 22s of the diameter expansion part 22 through an adhesive 50, the adhesive 50 is filled in a gap 30 between the base end face 15k and the tip 22s, and the gap 30 is thereby closed, so that the outer circumferential face 21g is fixed to the inner circumferential face 15n by the adhesive 50.

Description

  The present invention relates to a lens unit that is fixed in a distal end rigid member that constitutes a distal end portion that is located at the distal end in the insertion direction of an insertion portion of an endoscope, and an endoscope that includes the lens unit.

  In recent years, endoscopes inserted into a subject have been widely used in the medical field and the industrial field. The endoscope can observe the inside of the subject by inserting an elongated insertion portion into the subject.

  A lens unit for observing the inside of the subject is provided in the distal end portion located at the distal end in the insertion direction of the insertion portion of the endoscope (hereinafter simply referred to as the distal end).

  The lens unit has a plurality of lenses, and the plurality of lenses are held by a lens frame fixed in a through hole formed so as to penetrate the distal end hard member constituting the distal end portion along the insertion direction. Yes.

  Further, among the plurality of lenses, the objective lens positioned on the most distal side in the insertion direction (hereinafter simply referred to as the distal end side) is held by the lens frame so as to be exposed from the distal end surface of the distal end portion.

  The plurality of lenses have a configuration in which the outer peripheral surfaces of the plurality of lenses are held in the lens frame by being bonded and fixed to the inner peripheral surface of the lens frame with an adhesive made of an epoxy resin or the like. It is well known.

  Here, a known plano-concave lens in which a spherical notch recessed toward the distal end side of the objective lens is formed at the center of the objective lens in the radial direction on the base end surface of the objective lens is well known. is there.

  However, if there is a temperature difference between the lens frame and the subject, moisture will enter the lens frame from the subject via the adhesive between the inner peripheral surface of the lens frame and the outer peripheral surface of the objective lens. As a result of entering, there is a problem in that water vapor is likely to accumulate in the spherical part and the spherical part becomes cloudy.

  Incidentally, such a problem is that when the thermal stress or strong impact is applied to the tip, the adhesive peels off from the interface with the inner peripheral surface of the lens frame or the outer peripheral surface of the objective lens. When the agent is peeled off, moisture easily enters from the inside of the subject into the spherical part, so that the agent is more likely to be generated.

  In view of such a problem, in FIG. 5 of Patent Document 1, an optical component that covers the outer peripheral surface of the front end side of the lens frame and covers the front end surface of the objective lens and the front end of the lens frame is soldered to the front end surface of the front end hard member. In other words, the distal end side of the lens frame is fitted into the proximal end side in the insertion direction of the optical component fixed to the distal end surface of the distal end rigid member (hereinafter simply referred to as the proximal end side). The configuration of the tip is disclosed.

  According to such a configuration, the water entrance path from the inside of the subject to the spherical notch portion is more than the configuration in which the outer peripheral surface of the objective lens is simply fixed to the inner peripheral surface of the lens frame via an adhesive. And the optical component fitting portion is made longer, and further, the optical component is fixed to the distal end surface of the hard end member by soldering the optical component to prevent moisture from entering the lens frame, thereby preventing clouding of the spherical portion. be able to.

  In Patent Document 1, an optical component is used as a lens having a concavo-convex shape located in front of the objective lens in the insertion direction (hereinafter simply referred to as the front), thereby forming a part of the lens unit, that is, the objective. It is also disclosed that it may be used as a lens.

JP 2003-169775 A

  However, in the configuration of the distal end portion disclosed in Patent Document 1, as described above, the optical component has a size that covers the outer peripheral surface on the distal end side of the lens frame. It is formed larger in the radial direction than the outer diameter.

  For this reason, when the optical component is an objective lens and the objective lens is fixed to the distal end side of the lens frame as a lens unit, the outer diameter on the distal end side of the lens unit is increased by the optical component. There was a problem.

  Here, usually, an image pickup device for picking up an image of a part in the subject imaged on a plurality of lenses is held inside the base end side of the lens frame constituting the lens unit. The electric board is connected, and an elongated signal cable extends from the electric board. Hereinafter, a lens unit provided with an image pickup element, an electric board, and a signal cable is referred to as an image pickup unit.

  Therefore, when fixing the distal end side of the lens unit, that is, the distal end side of the imaging unit in the through hole of the distal end rigid member, the imaging unit has a signal cable, so that it is very elongated. In consideration of the above, it is common to use a technique in which the front end side of the imaging unit is inserted from the rear in the insertion direction (hereinafter simply referred to as the rear) toward the front and then fixed to the through hole.

  However, since the outer diameter of the lens frame is formed to be substantially the same as the diameter of the through hole in the configuration of the tip portion of Patent Document 1, an optical component having an outer diameter larger than the outer diameter of the lens frame is Due to size, it does not enter the through hole. For this reason, the front end side of the imaging unit to which the optical component is fixed cannot be inserted into the through hole from behind.

  Therefore, when fixing the distal end side of the imaging unit to the through hole, the distal end side of the imaging unit excluding the optical component is inserted from the rear into the through hole, and then the optical component is covered with the distal end side of the imaging unit. After fitting from the front, it must be soldered to the front end surface of the hard end member, and this fixing work is very complicated when using an optical component as an objective lens, making it difficult to adjust the optical axis and increasing the number of work steps. There was a problem such as.

  In the configuration of Patent Document 1, if an optical component used as an objective lens is fitted to the distal end side of the imaging unit inserted through the through hole and the optical component is soldered to the distal end surface of the distal end hard member, The optical component can be part of the lens unit. However, as described above, since the optical component cannot be inserted through the through-hole when fixed to the front end side of the lens unit, it cannot be formed integrally with other components constituting the lens unit. That is, in a state where the optical component is fixed, the lens unit cannot be fixed in the through hole. Therefore, when considered as a single lens unit, the optical component described in Patent Document 1 is a part of the lens unit. It can't be.

  From the above, in consideration of workability, in the lens unit, the objective lens is usually fixed to the lens frame in a general configuration in which the outer peripheral surface of the objective lens is fixed to the inner peripheral surface of the lens frame as described above. However, in this case, there is a problem that the spherical portion of the objective lens is likely to be clouded as described above. Furthermore, it has been desired to reduce the diameter of the front end side of the lens unit.

  The present invention has been made in view of the above circumstances, and is capable of preventing fogging of a spherical portion of an objective lens, realizing a reduction in diameter on the distal end side, and a lens unit that is easy to assemble into an endoscope, the lens An object is to provide an endoscope including a unit.

  In order to achieve the above object, in the lens unit according to one aspect of the present invention, the outer periphery of the enlarged diameter portion of the lens frame is disposed in the distal end hard member that constitutes the distal end portion that is located at the distal end in the insertion direction of the insertion portion of the endoscope. The lens unit is fixed in a state of being in contact with the distal end hard member, the distal end surface and the outer peripheral surface are exposed, and the lens frame is located on the inner side in the radial direction of the lens frame and on the distal end surface side from the base end surface An abutting surface is formed, and a spherical notch that is recessed toward the distal end surface side is formed at the radial center of the abutting surface, and the insertion direction is between the abutting surface and the base end surface And the lens frame is positioned to have the same outer diameter as the outer peripheral surface of the objective lens or positioned more radially outward than the outer peripheral surface. Front and having the outer periphery The enlarged-diameter portion located farther in the insertion direction than the base end surface of the objective lens, and the fitting portion to the objective lens protruding forward in the insertion direction from the enlarged-diameter portion. The gap between the base end surface of the objective lens and the tip of the enlarged diameter portion is filled with a fixing material to close the gap, and the outer peripheral surface of the fitting portion is It is fixed to the inner peripheral surface of the lens by the fixing material.

  An endoscope comprising a lens unit according to an aspect of the present invention is an endoscope comprising the lens unit according to any one of claims 1 to 9, wherein the lens unit is The tip of the objective lens is fixed in a through hole formed along the insertion direction in the tip configuration portion with the outer periphery of the enlarged diameter portion in contact with the inner peripheral surface of the through hole. The surface is exposed from the distal end of the distal end portion of the insertion portion, and the distal end cover that covers the distal end configuration portion or the distal end surface and the outer peripheral surface of the distal end configuration portion on the outer peripheral surface of the objective lens is an adhesive. It is pasted through.

  According to the present invention, it is possible to prevent fogging of the spherical portion of the objective lens, to realize a reduction in diameter on the distal end side, and to provide a lens unit that is easily assembled to an endoscope, and an endoscope including the lens unit. Can be provided.

The perspective view which shows the endoscope in which the lens unit of 1st Embodiment was provided in the front-end | tip part of an insertion part. Partial sectional view of the distal end of the insertion section along the line II-II in FIG. Sectional drawing which expands and shows the lens unit of FIG. Sectional drawing of the lens unit of 2nd Embodiment Sectional drawing which shows the modification which provided the clearance gap between the aperture plate and the front-end | tip of the fitting part of a 1st lens frame in the lens unit of FIG.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a perspective view showing an endoscope in which the lens unit of the present embodiment is provided in the distal end portion of the insertion portion.
As shown in FIG. 1, an endoscope 1 is connected to an insertion portion 2 to be inserted into a subject and a proximal end in the insertion direction S of the insertion portion 2 (hereinafter simply referred to as a proximal end). The main part is configured by including an operation unit 6, a universal cord 7 extending from the operation unit 6, and a connector 8 provided at an extended end of the universal cord 7.

  Since the connector 8 can be connected to a known light source device (not shown), the endoscope 1 can be connected to peripheral devices.

  The insertion portion 2 includes a distal end portion 3 positioned at the distal end of the insertion portion 2 in the insertion direction S, and bending operation knobs 6 n and 6 m provided on the operation portion 6 and connected to the proximal end of the distal end portion 3. For example, the main portion includes a bending portion 4 that is bent in four directions, up, down, left, and right, and an elongated and flexible flexible tube portion 5 that is connected to the base end of the bending portion 4. Has been.

  Next, the configuration of the lens unit provided in the tip 3 will be described with reference to FIGS. 2 is a partial cross-sectional view of the distal end portion of the insertion portion taken along line II-II in FIG. 1, and FIG. 3 is an enlarged cross-sectional view of the lens unit of FIG.

  As shown in FIG. 2, the distal end portion 3 of the insertion portion 2 includes a distal end hard member 13 made of, for example, a hard metal.

  In addition, the lens unit 100 is fixed in the distal end hard member 13. Specifically, a through hole 13h that penetrates the distal end surface 13s of the distal end hard member 13 and a base end surface (not shown) along the insertion direction S is formed in the distal end hard member 13, and the lens unit is formed in the through hole 13h. 100 is fixed.

  As shown in FIG. 3, the lens unit 100 includes an objective lens 15, a diaphragm plate 18, and a lens frame 20, and a main part is configured.

  The objective lens 15 is formed in a substantially cylindrical shape whose outer shape has a predetermined length along the insertion direction S, and the front end surface 15s and the outer peripheral surface 15g are exposed to the outside.

  In addition, the objective lens 15 has a cylindrical space 15i having a diameter smaller than the outer diameter of the objective lens 15 and extending forward from the base end face 15k at the center of the base end face 15k in the radial direction K of the objective lens 15. Has been.

  Since the space 15i is formed in the base end surface 15k, the abutting surface 15t of the lens frame 20 is formed on the inner side in the radial direction from the base end surface 15k and on the front end surface 15s side from the base end surface 15k. An inner peripheral surface 15n along the insertion direction S is formed between the outer end portion in the radial direction K of the abutting surface 15t and the inner end portion in the radial direction K of the base end surface 15k.

  Furthermore, a spherical notch 15q that is recessed toward the front end surface 15s is formed at substantially the center in the radial direction K of the abutting surface 15t. That is, the objective lens 15 is formed as a known plano-concave lens in which a spherical notch 15q is formed at a position facing the front end surface 15s.

  The lens frame 20 is formed in a cylindrical shape and holds a plurality of lenses 25 therein.

  The lens frame 20 has an outer periphery 22g that is positioned so as to have the same outer diameter as the outer peripheral surface 15g of the objective lens 15 or that is positioned radially outward from the outer peripheral surface 15g, and is rearward of the base end surface 15k of the objective lens 15. The enlarged-diameter portion 22 is provided.

  As shown in FIG. 2, the lens unit 100 is made of an adhesive or the like in a state where the outer periphery 22g of the enlarged diameter portion 22 is in contact with the inner peripheral surface 13n of the distal end hard member 13 formed by the through hole 13h. It is fixed in the through hole 13h.

  Further, since the enlarged diameter portion 22 is positioned behind the proximal end surface 15k, a gap 30 exposed to the outside in the radial direction K is provided between the proximal end surface 15k and the distal end 22s of the enlarged diameter portion 22. Is formed.

  Of the adhesive 50 that is a fixing material, the distal end 22s is fixed to the base end face 15k by, for example, an epoxy-based adhesive 50a that is a first fixing material filled in the gap 30.

  Since the gap 30 is exposed outside in the radial direction K, the adhesive 50a filled in the gap 30 is also exposed outside in the radial direction K in the filled state. It is easily visible by the assembling worker that the base end face 15k and the front end 22s are adhered by the adhesive 50a.

  In addition, the lens frame 20 includes a fitting portion 21 to the objective lens 15 that has a smaller diameter than the enlarged diameter portion 22 and projects forward from the enlarged diameter portion 22.

  The fitting portion 21 is filled between the outer peripheral surface 21g and the inner peripheral surface 15n communicating with the gap 30 in the adhesive 50 after the outer peripheral surface 21g is fitted to the inner peripheral surface 15n of the objective lens 15. It is fixed to the inner peripheral surface 15n by an adhesive 50b which is a second fixing material. That is, the lens frame 20 is fixed by fitting the fitting portion 21 into the inner peripheral surface 15 n of the objective lens 15.

The adhesive 50a and the adhesive 50b may be made of the same adhesive. For example, when the adhesive 50a and the adhesive 50b are made of, for example, a photo-curing adhesive, the adhesive 50a filled in the gap 30 is specifically irradiated with the light L. As shown in FIG. 3, the adhesive 50b cured by being irradiated with the light L from the outside in the radial direction K and filled between the inner peripheral surface 15n and the outer peripheral surface 21g includes the adhesive 50a and Similarly, it hardens | cures by irradiating the light L from the outer side of the radial direction K through the outer peripheral surface 15g of the objective lens 15. FIG.
Note that at least the adhesive 50b is preferably composed of a photo-curing adhesive. This is because the photo-curing adhesive has anaerobic properties, so that it is difficult for moisture to enter from the outside if the space is filled between the inner peripheral surface 15n and the outer peripheral surface 21g. .
Further, the adhesive 50a and the adhesive 50b may be composed of a thermosetting adhesive. Furthermore, the adhesive 50a and the adhesive 50b may be made of solder.
Further, the adhesive 50a and the adhesive 50b may be different types. For example, one of the adhesive 50a and the adhesive 50b may be composed of an adhesive, and the other may be composed of solder that is less permeable to moisture than the adhesive. According to such a configuration, it is possible to prevent fogging of the objective lens 15 in order to prevent moisture from entering.

Since the objective lens 15 is made of a transparent member and the outer peripheral surface 15g is exposed to the outside, the outer peripheral surface 21g and the inner peripheral surface 50n are bonded to the adhesive 50b by an assembly operator of the lens unit 100. It can be easily visually recognized through the outer peripheral surface 15g of the objective lens 15.
If the adhesive 50b is made of colored solder, the adhesive 50b can be more easily visually recognized through the outer peripheral surface 15g of the objective lens 15.

  As described above, since the inner peripheral surface 15n of the objective lens 15 is a portion where the outer peripheral surface 21g of the fitting portion 21 is fitted and fixed, after the fitting, the objective lens 15 and the lens 25 The optical axis is formed with high positional accuracy with respect to the objective lens 15 and the surface roughness is finer and smoother than the outer peripheral surface 15g.

  Further, the tip 21 s of the fitting portion 21 is positioned to face the abutting surface 15 t of the objective lens 15. Further, an outer peripheral surface 18g of the diaphragm plate 18 having an opening 18h formed in the center in the radial direction K between the tip 21s in the insertion direction S and the abutting surface 15t with respect to the inner peripheral surface 15n of the objective lens 15. It is fixed.

  Specifically, the outer peripheral surface 18g of the diaphragm plate 18 is formed by the adhesive 90 filled between the outer peripheral surface 18g and the inner peripheral surface 15n communicating between the inner peripheral surface 15n and the outer peripheral surface 21g. It is fixed to the peripheral surface 15n.

  The adhesive 90 filled between the outer peripheral surface 18g and the inner peripheral surface 15n may be the same as the adhesive 50b filled between the inner peripheral surface 15n and the outer peripheral surface 21g. For example, it is comprised from the photocurable adhesive agent. In this case, similar to the adhesive 50b filled between the inner peripheral surface 15n and the outer peripheral surface 21g, the adhesive 90 emits the light L from the outer side in the radial direction K through the outer peripheral surface 15g of the objective lens 15. It is cured by irradiation.

  Further, the diaphragm plate 18 is also fixed to the abutting surface 15t and the tip 21s of the fitting portion 21.

  Specifically, it is filled between the diaphragm plate 18 communicating with the outer peripheral surface 18g and the inner peripheral surface 15n and the tip 21s, and is filled between the diaphragm plate 18 and the abutting surface 15t. The diaphragm plate 18 is fixed to the abutting surface 15 t and the tip 21 s of the fitting portion 21 by the adhesive 90.

  The adhesive 90 filled between the diaphragm plate 18 and the abutting surface 15t is the same as the adhesive 90 filled in the gap between the diaphragm plate 18 and the tip 21s, but may be different. Absent.

  The adhesive filled in the gap between the diaphragm plate 18 and the tip 21s and the adhesive filled between the diaphragm plate 18 and the abutting surface 15t are also made of a photo-curing adhesive. It doesn't matter. In this case, the adhesive 90 is cured by being irradiated with the light L from the outer side in the radial direction K through the outer peripheral surface 15 g of the objective lens 15.

  From the above, in a state where the outer peripheral surface 21 g of the fitting portion 21 is fixed to the inner peripheral surface 15 n of the objective lens 15, the tip 21 s of the fitting portion 21 hits the abutting surface 15 t via the diaphragm plate 18. ing.

  In addition, another frame body is fitted to the outer periphery of the base end side of the lens frame 20, and the above-described image sensor is held in the other frame body. A signal cable is extended from the electrical board. That is, as described above, the lens unit 100 constitutes an imaging unit together with the imaging element, the electric board, and the signal cable. The signal cable is inserted to the connector 8 through the insertion unit 2, the operation unit 6, and the universal cord 7. When the connector 8 is connected to an external device, an image in the subject imaged by the imaging unit is obtained. It is transmitted to an external device.

Next, a method for assembling the lens unit 100 having such a configuration will be briefly described. In the following assembly method, the case where the adhesive 50a, the adhesive 50b, and the adhesive 90 are made of the same material is described as an example.
First, the operator adheres and fixes the diaphragm plate 18 to the abutting surface 15t of the objective lens 15.

  Next, the operator internally fits the outer peripheral surface 21g of the fitting portion 21 of the lens frame 20 holding the lens 25 therein to the inner peripheral surface 15n of the objective lens 15, and the tip 21s of the fitting portion 21 is It abuts against the abutment surface 15t via the diaphragm plate 18.

  Thereafter, the operator fills the gap 90 between the base end face 15 k of the objective lens 15 and the tip 22 s of the enlarged diameter portion 22 of the lens frame 20 with the adhesive 90 and the adhesive 50. The filled adhesive 90 and adhesive 50 are also filled between the outer peripheral surface 21 g and the inner peripheral surface 15 n and between the tip 21 s and the diaphragm plate 18.

  Finally, the operator cures the adhesive 50 by irradiating the adhesive 90 and the adhesive 50 with light L from the outside in the radial direction K.

  In this way, the lens unit 100 is assembled by fixing the lens frame 20 together with the diaphragm plate 18 to the objective lens 15.

  As shown in FIG. 2, the lens unit 100 is fixed in the through hole 13h with the outer periphery 22g of the enlarged diameter portion 22 in contact with the inner peripheral surface 13n as described above.

  In a state where the lens unit 100 is fixed in the through hole 13h, the front end surface 15s of the objective lens 15 is exposed forward from the front end 3s of the front end portion 3. Further, the outer peripheral surface 15 g of the objective lens 15 is covered with a front end cover 11 that covers the outer peripheral surface 13 g and the front end surface 13 s of the distal end hard member 13. Pasted. Note that the outer peripheral surface 15g may be covered by the distal end hard member 13.

  Thus, since the outer peripheral surface 15g is a part where the front end cover 11 or the front end hard member 13 is attached, it is more accurate than the inner peripheral surface 15n to which the fitting portion 21 of the lens frame 20 is fitted. In order to improve the adhesiveness by the adhesive 55 without being formed well, for example, the surface roughness may be larger than that of the inner peripheral surface 15n.

Next, a method for assembling the lens unit 100 in the through hole 13h will be briefly described.
First, the operator inserts the lens unit 100 located on the distal end side in the imaging unit to which the above-described imaging element, electric board, and signal cable are fixed from the rear with respect to the through hole 13h. Is inserted from the tip 3s of the tip 3 until it is exposed.

  Next, the operator fixes the lens unit 100 in the through hole 13h with an adhesive or the like with the outer peripheral surface 22g of the enlarged diameter portion 22 of the lens frame 20 in contact with the inner peripheral surface 13n.

  Finally, the operator adheres the distal end cover 11 covered with the distal end surface 13 s and the outer circumferential surface 13 g of the distal end hard member 13 and the outer circumferential surface 15 g of the objective lens 15 using an adhesive 55.

  As described above, in the present embodiment, in the lens unit 100, the outer peripheral surface 15g of the objective lens 15 is exposed to the outside.

  Further, it is shown that the outer peripheral surface 21g of the fitting portion 21 of the lens frame 20 is fitted and fixed to the inner peripheral surface 15n of the objective lens 15.

  According to this, as shown by the one-dot chain line arrow in FIG. 3, the water ingress path to the spherical notch 15q of the objective lens 15 is between the base end surface 15k and the front end 22s, and the inner peripheral surface 15n. Since it is longer than the configuration in which the lens frame is simply fixed to the outer periphery of the objective lens, such as between the outer peripheral surface 21g, between the tip 21s and the diaphragm plate 18 or between the diaphragm plate 18 and the abutting surface 15t, The ball notch 15q is less likely to be clouded than before.

  Note that, as shown in FIG. 2, when the lens unit 100 is fixed in the distal end portion 3, as shown by the dashed line arrow in FIG. The approach path is formed between the base end surface 15k and the front end 22s, between the inner peripheral surface 15n and the outer peripheral surface 21g, between the front end 21s and the stop plate 18, or between the stop plate 18 and the abutment surface 15t. Since it becomes longer, it becomes more prominent.

  Further, since the outer peripheral surface 15g is exposed to the outside, that is, no lens frame or the like is positioned around the outer peripheral surface 15g, the lens unit 100 can be reduced in diameter around the objective lens 15.

  Further, since the outer peripheral surface 15g of the objective lens 15 is exposed, the objective lens 15 can be used without changing the outer diameter on the tip side of the lens unit 100 as compared with the configuration in which the outer peripheral surface of the conventional objective lens is fixed to the lens frame. The outer diameter of the lens 15 can be increased.

  In the present embodiment, the adhesive 50a that bonds the base end surface 15k of the objective lens 15 and the distal end 22s of the enlarged diameter portion 22, the outer peripheral surface 21g of the fitting portion 21, and the inner peripheral surface 15n of the objective lens 15 is used. It was shown that the adhesive 50b that can be adhered to each other is visible from the outside in the radial direction K. Further, it is indicated that at least the adhesive 50b is composed of a photo-curing adhesive that is cured by being irradiated with the light L from the outer side in the radial direction K through the outer peripheral surface 15g of the objective lens 15.

  According to this, the adhesive 50 b can be easily cured in a short time, and the operator can easily visually recognize the cured state of the adhesive 50 b through the outer peripheral surface 15 g of the objective lens 15. . If the adhesive 50a and the adhesive 90 are also made of a photo-curing adhesive, the adhesive 50a and the adhesive 90 can be easily cured in a short time, and the adhesive 50a and the adhesive 90 can be easily cured. The operator can easily visually recognize the cured state.

  Furthermore, as shown in FIG. 2, in the case where the lens unit 100 is fixed in the tip portion 3, the inner peripheral surface 15n is bonded and fixed to the outer peripheral surface 21g via an adhesive 50b, and the outer peripheral surface Since 15 g is bonded and fixed to the tip cover 11 via the adhesive 55, the objective lens 15 is difficult to come off.

  Further, the outer periphery 22g of the enlarged diameter portion 22 of the lens frame 20 is positioned so as to have the same outer diameter as the outer peripheral surface 15g of the objective lens 15, or is positioned on the outer side in the radial direction from the outer peripheral surface 15g. Even in a state where the lens 15 is fixed to the lens frame 20, the lens unit 100 can be easily assembled by being inserted through the through hole 13h from the rear.

  From the above, it is possible to prevent the spherical portion 15q of the objective lens 15 from being fogged, to realize a reduction in diameter on the distal end side, and to the lens unit 100 that is easy to assemble into the endoscope 1, and an endoscope equipped with the lens unit 100 A mirror 1 can be provided.

(Second Embodiment)
FIG. 4 is a cross-sectional view of the lens unit of the present embodiment.

  The lens unit according to the second embodiment and the configuration of the endoscope including the lens unit are the same as the lens unit according to the first embodiment illustrated in FIGS. 1 to 3 and the endoscope including the lens unit. Compared with the mirror, the objective lens and the lens frame of the lens unit are fixed by metal bonding, and the lens frame is composed of a first lens frame and a second lens frame. . Therefore, only this difference will be described, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted.

  As shown in FIG. 4, in the lens unit 100 of the present embodiment, the lens frame 20 includes a first lens frame 120 having a fitting portion 121 for the objective lens 15, and the lens unit 100 is in the through hole 13h. The main part is composed of the second lens frame 220 having the enlarged diameter portion 222 with which the outer periphery 222g abuts against the inner peripheral surface 13n.

  The first lens frame 120 is formed in a cylindrical shape and holds a plurality of lenses 125 inside. The second lens frame 220 is formed in a cylindrical shape, holds a plurality of lenses 225 therein, and the distal end side is fixed to the outer periphery on the proximal end side of the first lens frame 120.

  The second lens frame 220 has an outer periphery 222g that is positioned to have the same outer diameter as the outer peripheral surface 15g of the objective lens 15 or that is positioned radially outward from the outer peripheral surface 15g, and a base end surface 15k of the objective lens 15. An enlarged-diameter portion 222 located rearward is provided.

  As described above, the lens unit 100 has a through-hole formed by an adhesive or the like in a state where the outer periphery 222g of the enlarged diameter portion 222 is in contact with the inner peripheral surface 13n of the distal end hard member 13 formed by the through-hole 13h. It is fixed within 13h.

  Further, since the enlarged diameter portion 222 is located behind the proximal end surface 15k, the gap 30 exposed to the outside in the radial direction K is between the proximal end surface 15k and the distal end 222s of the enlarged diameter portion 222. Is formed. Of the fixing material 200, the metal film 70 serving as a vapor deposition surface formed on the base end surface 15k is formed by the adhesive 150 and the first bonding material 80a which are the first fixing material 200a filled in the gap 30. On the other hand, the tip 222s is fixed.

  In addition, as the adhesive 150, a photocurable adhesive can be used. Therefore, the adhesive 150 filled in the gap 30 is cured by being irradiated with the light L, specifically, by being irradiated with the light L from the outside in the radial direction K as shown in FIG. Has been.

  Further, since the gap 30 is exposed outside in the radial direction K, the adhesive 150 and the first bonding material 80a filled in the gap 30 are also exposed outside in the radial direction K in the filled state. Therefore, it is easily visible by an operator who assembles the lens unit 100 that the base end face 15k and the front end 222s are attached by the adhesive 150 and the first bonding material 80a.

  Further, the first lens frame 120 includes a fitting portion 121 to the objective lens 15 that has a smaller diameter than the enlarged diameter portion 222 and projects forward from the enlarged diameter portion 222.

In the fitting portion 121, the outer peripheral surface 121 g is fitted to the inner peripheral surface 15 n of the objective lens 15, and then the metal film 60 serving as a vapor deposition surface formed on the outer peripheral surface 121 g is attached to the inner peripheral surface 15 n. Among these, it is fixed by a second bonding material 80b which is the second fixing material 200b.
The second bonding material 80b and the first bonding material 80a may be made of the same material. The second bonding material 80b is electrically connected to the first bonding material 80a.
In addition, the metal film 60 and the metal film 70 are metal-bonded by the first bonding material 80 a and the second bonding material 80 b, so that the fitting portion 121 of the objective lens 15 is connected to the first lens frame 120. It is fitted and fixed to the inner peripheral surface 15n.

  The first bonding material 80a and the second bonding material 80b include, for example, solder. That is, soldering is an example of metal bonding. In the present embodiment, the outer peripheral surface 121g is fitted to the inner peripheral surface 15n in a non-adhesive manner.

  In addition, since the gap 30 is exposed outside in the radial direction K, the first bonding material 80a filled in the gap 30 is also exposed outside in the radial direction K in the filled state. It is easily visible that the inner peripheral surface 15n and the outer peripheral surface 121g are joined by the joining material 80 by an assembly operator of the unit 100.

  Further, since the first bonding material 80a is filled in the gap 30 behind the base end face 15k, the first bonding material 80a is filled in a place where the light entering the objective lens 15 is not affected. Generation of flare by the bonding material 80a is prevented.

  Further, the tip 121s of the fitting portion 121 is similar to the first embodiment described above in the state where the outer peripheral surface 121g of the fitting portion 121 is fixed to the inner peripheral surface 15n of the objective lens 15, as shown in FIG. Through the abutment surface 15t.

  In this embodiment, the diaphragm 18 may be bonded and fixed to the inner peripheral surface 15n, the abutting surface 15t, and the tip 121s.

  Note that another frame body is fitted to the outer periphery of the base end side of the second lens frame 220, and the above-described image sensor is held in the other frame body. An electric board is connected, and a signal cable extends from the electric board. That is, also in this embodiment, as described above, the lens unit 100 constitutes an imaging unit together with the imaging element, the electric board, and the signal cable.

Next, a method for assembling the lens unit 100 having such a configuration will be briefly described.
First, the operator adheres and fixes the diaphragm plate 18 to the abutting surface 15t of the objective lens 15.

  Next, the operator internally fits the outer peripheral surface 21 g of the fitting portion 21 of the lens frame 20 holding the lens 25 therein to the inner peripheral surface of the objective lens 15, and restricts the tip 21 s of the fitting portion 21. It abuts against the abutment surface 15t via the plate 18.

  Thereafter, the operator joins the metal film 70 on the base end surface 15k of the objective lens 15 and the metal film 60 on the outer peripheral surface 121g of the fitting portion 121 with the first bonding material 80a and the second bonding material 80b. To do.

  Next, the operator fits and fixes the distal end side of the second lens frame 220 to the outer periphery on the proximal end side of the first lens frame 120.

  Finally, the operator fills the gap 30 with the adhesive 150 and irradiates the adhesive 150 with light L from the outside in the radial direction K, thereby curing the adhesive 150.

  In this way, the lens unit 100 is assembled by fixing the lens frame 20 together with the diaphragm plate 18 to the objective lens 15.

  The fixing structure in the through hole 13h of the lens unit 100 and the method for assembling the lens unit 100 in the through hole 13h are the same as those in the first embodiment described above. Omitted.

  Thus, in the present embodiment, the outer peripheral surface 121g of the fitting portion 121 of the first lens frame 120 is internally fitted to the inner peripheral surface 15n of the objective lens 15, and the base end surface 15k of the objective lens 15 is thus fitted. It was shown that the metal film 70 and the metal film 60 on the outer peripheral surface 121g are metal-bonded by the first bonding material 80a and the second bonding material 80b.

  According to this, the first bonding material 80a and the second bonding material 80b ensure that moisture enters between the inner peripheral surface 15n and the outer peripheral surface 121g, that is, the spherical notch 15q. Since it can be prevented, it is possible to more reliably prevent the occurrence of fogging in the ball notch 15q than in the first embodiment.

  Further, the operator can easily recognize that the objective lens 15 is fixed to the first lens frame 120 by observing the first bonding material 80a that is filled in the gap 30 and exposed to the outside. can do.

  Further, since the gap 30 is exposed to the outside in the radial direction K, the metal bonding work between the metal film 60 and the metal film 70 in the gap 30, that is, the fixing work between the inner peripheral surface 15n and the outer peripheral surface 121g is performed. It has become easier.

  Other effects are the same as those of the first embodiment described above.

  Hereinafter, a modification will be described with reference to FIG. FIG. 5 is a cross-sectional view showing a modification in which a clearance is provided between the aperture plate and the tip of the fitting portion of the first lens frame in the lens unit of FIG.

  In the present embodiment described above, as shown in FIG. 4, the tip 121 s of the fitting portion 121 is in a state where the outer peripheral surface 121 g of the fitting portion 121 is fixed to the inner peripheral surface 15 n of the objective lens 15. It abuts against the abutting surface 15t via the diaphragm plate 18. In other words, the tip 121s is shown to abut against the aperture plate 18.

  Not limited to this, as shown in FIG. 5, in the insertion direction S, a clearance C may be provided between the tip 121 s of the fitting portion 121 of the first lens frame 120 and the diaphragm plate 18. . In the configuration shown in FIG. 5, the diaphragm plate 18 and the abutting surface 15t of the objective lens 15 are fixed with an adhesive.

  This is because when the objective lens 15 is assembled to the fitting portion 121, the objective lens 15 is inserted in the insertion direction S before the inner peripheral surface 15n of the objective lens 15 is bonded and fixed to the outer peripheral surface 121g of the fitting portion 121. When the adjustment operation is performed to obtain a predetermined angle of view by moving back and forth, the diaphragm plate 18 does not necessarily abut against the tip 121s, and the gap between the tip 121s and the diaphragm plate 18 as shown in FIG. This is because the clearance C may occur.

  According to such a configuration, when the objective lens 15 is assembled to the outer peripheral surface 121g of the fitting portion 121, the diameter of the objective lens 15 and the second lens frame 220 to which the first lens frame 120 is fixed is increased. Each of the portions 222 can be fixed to a jig to adjust the objective lens 15 in the insertion direction S, and the outer peripheral surface 121g of the fitting portion 121 can be maintained while the objective lens 15 is fixed to the jig. It is possible to perform an adhesive fixing operation of the inner peripheral surface 15n of the objective lens 15 with respect to the lens. Other effects are the same as those of the present embodiment described above.

DESCRIPTION OF SYMBOLS 1 ... Endoscope 2 ... Insertion part 3 ... Tip part 3s ... Tip of tip part 11 ... Tip cover 13 ... Tip hard member 13g ... Outer peripheral surface of tip hard member 13h ... Through hole of tip hard member 13n ... Tip hard member Inner peripheral surface 13s: distal end surface of the hard tip member 15 ... objective lens 15g ... outer peripheral surface of the objective lens 15k ... base end surface of the objective lens 15n ... inner peripheral surface of the objective lens 15q ... spherical portion of the objective lens 15s ... Front end surface 15t: Abutting surface of the objective lens 18 ... Diaphragm plate 18h ... Opening of aperture plate 20 ... Lens frame 21 ... Fitting portion 21g ... Outer periphery of fitting portion 21s ... End of fitting portion 22 ... Expanded portion 22g ... The outer periphery of the enlarged diameter portion 22s ... the tip of the enlarged diameter portion 30 ... the gap 50 ... the fixing material (adhesive)
50a: Adhesive (first fixing material)
50b ... Adhesive (second fixing material)
55 ... Adhesive 60 ... Metal film 70 ... Metal film 80a ... First bonding material (first fixing material)
80b ... 2nd joining material (2nd fixing material)
DESCRIPTION OF SYMBOLS 90 ... Adhesive 100 ... Lens unit 120 ... 1st lens frame 121 ... Fitting part 121g ... Outer periphery of a fitting part 121s ... Tip of fitting part 150 ... Adhesive (1st fixing material)
DESCRIPTION OF SYMBOLS 200 ... Fixing material 200a ... 1st fixing material 200b ... 2nd fixing material 220 ... 2nd lens frame 222 ... Diameter expansion part 222s ... Tip of diameter expansion part 222g ... Outer diameter of diameter expansion part K ... Radial direction S ... Insertion direction

Claims (10)

A lens unit fixed in a state where the outer periphery of the enlarged diameter portion of the lens frame is in contact with the distal end hard member in the distal end rigid member constituting the distal end portion located at the distal end in the insertion direction of the insertion portion of the endoscope Because
The front end surface and the outer peripheral surface are exposed, the abutting surface of the lens frame is formed on the inner side in the radial direction of the lens frame and on the front end surface side with respect to the base end surface, and the radial surface of the abutting surface is in the center in the radial direction. The objective lens is provided with an inner peripheral surface formed along the insertion direction between the abutting surface and the base end surface, and a spherical notch that is recessed on the distal end surface side is formed,
The lens frame has the outer periphery located so as to have the same outer diameter as the outer peripheral surface of the objective lens, or positioned more radially outward than the outer peripheral surface, and more than the base end surface of the objective lens. The enlarged diameter portion positioned rearward in the insertion direction, and a fitting portion to the objective lens protruding forward in the insertion direction than the enlarged diameter portion,
The gap is closed by filling the gap between the base end face of the objective lens and the tip of the enlarged diameter portion with a fixing material, and the outer peripheral surface of the fitting portion is The lens unit fixed to the inner peripheral surface by the fixing material. The fixing material is composed of a first fixing material and a second fixing material,
The first fixing material is filled in the gap between the base end surface of the objective lens and the tip of the enlarged diameter portion,
The lens unit according to claim 1, wherein the second fixing member is filled between the outer peripheral surface of the fitting portion and the inner peripheral surface of the objective lens. A diaphragm plate in which an opening is formed at the center in the radial direction at a position between the abutting surface of the objective lens and a tip in the insertion direction of the fitting portion with respect to the inner peripheral surface of the objective lens. Is fixed,
The lens unit according to claim 2, wherein the tip of the fitting portion abuts against the abutting surface via the diaphragm plate.   The lens unit according to claim 3, wherein the diaphragm plate is fixed to the abutting surface and the tip of the fitting portion via an adhesive.   The first fixing member and the second fixing member are adhesives filled between the inner peripheral surface of the objective lens and the outer peripheral surface of the fitting portion together with the gap. The lens unit according to any one of claims 2 to 4.   The lens unit according to claim 4, wherein at least the second fixing material is a photo-curing adhesive that is cured by light irradiated from outside in the radial direction. A metal film is provided on the outer peripheral surface of the fitting portion and the base end surface of the objective lens,
The first fixing material is composed of a first bonding material and an adhesive that block the gap between the metal film provided on the base end surface of the objective lens and the tip of the enlarged diameter portion. ,
The second fixing material is composed of a second bonding material filled between the metal film provided on the outer peripheral surface of the fitting portion and the inner peripheral surface of the objective lens,
The metal film provided on the outer peripheral surface of the fitting portion and the metal film provided on the base end surface of the objective lens are metal-bonded by the first bonding material and the second bonding material. The lens unit according to any one of claims 2 to 4, wherein:   The lens unit according to claim 7, wherein the first bonding material is exposed to the outside in the radial direction by being filled in the gap.   The lens frame includes a first lens frame having the fitting portion, and a second lens having a diameter-enlarged portion that is fitted to an outer periphery of the first lens frame on the proximal end side in the insertion direction. The lens unit according to claim 1, further comprising a frame. An endoscope comprising the lens unit according to any one of claims 1 to 9,
In the lens unit, in the through hole formed in the distal end hard member along the insertion direction, the outer periphery of the enlarged diameter portion is applied to the inner peripheral surface of the distal end hard member formed by the through hole. It is fixed in contact,
The distal end surface of the objective lens is exposed from the distal end of the distal end portion of the insertion portion, and the distal end rigid member or the distal end surface and the outer circumferential surface of the distal end rigid member are disposed on the outer peripheral surface of the objective lens. An endoscope comprising a lens unit, wherein a covering front end cover is attached via an adhesive.

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