JP2005227728A - Manufacturing method of lens joining body, lens joining body and endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a lens joining body, with which airtightness and durability of the joint section between a lens and a frame body are made superior while simplifying the body and reducing the cost and to provide the lens joining body and an endoscope. <P>SOLUTION: In the manufacturing method of the lens joining body, low melting point glass having a thermal expansion coefficient, which is between the thermal expansion coefficient of a tip member 9 and the thermal expansion coefficient of a flat concave lens 13, is provided between the tip member 9 and the flat concave lens 13 and the tip member 9 and the flat concave lens 13 are joined by the low melting point glass while heating the low melting point glass. In the obtained lens joining body, the tip member 9 and the lens 13 are joined through an adhesive layer 1129E constituted by the low melting point glass. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a lens joined body, a lens joined body, and an endoscope.

  In the medical field, endoscopes are used for examination and diagnosis of the digestive tract and the like. This endoscope has an insertion portion (endoscopic flexible tube) to be inserted into a body cavity, and an operation portion that is installed on the proximal end side of the insertion portion and performs a bending operation on the distal end portion of the insertion portion. doing.

  The insertion portion includes a flexible tube having flexibility so that the insertion portion can be inserted into a bent body cavity and follow the bending portion, and a bending portion that is bent at the distal end side thereof.

  An objective lens, an eyepiece lens, and the like are provided at the end of the endoscope. As these joining methods, those using an organic adhesive are known (for example, see Patent Document 1).

  Since such a medical endoscope is used by being inserted into a body cavity, it is contaminated by living tissue, blood, pathogens, etc. attached at the time of insertion. For this reason, after completion of the inspection and processing, the endoscope is subjected to cleaning, disinfection, sterilization processing, and the like.

  For this endoscope sterilization treatment, for example, a chemical solution treatment such as glutaraldehyde is widely used. In recent years, sterilization treatment is sometimes performed under severe conditions such as hydrogen peroxide plasma sterilization and high-temperature high-pressure steam sterilization for the purpose of more reliably preventing the occurrence of infectious diseases.

  However, since glass and metal are generally used for the lens and the frame that supports the lens, the organic adhesive described above may be affected by the chemical solution and deteriorate. In addition, since the coefficient of thermal expansion after curing is significantly larger than that of the lens and the frame that supports the lens, for example, during high-temperature high-pressure steam sterilization or hydrogen peroxide plasma sterilization, Stress occurs between the members, and the adhesive deteriorates and peels off during repeated sterilization, so that water vapor may enter the endoscope from the peeled portion of the adhesive. Also, conventional endoscopes cannot exhibit sufficient chemical resistance against sterilization processing performed under harsh conditions such as hydrogen peroxide plasma sterilization, and in particular, bonded portions formed by bonding. However, there was a tendency to be easily damaged.

JP 2000-212075 A

  An object of the present invention is to provide a method for manufacturing a lens joined body, a lens joined body, and an endoscope that can improve the airtightness and durability of the joint between the lens and the frame.

The object is achieved by the present inventions (1) to (12) below.
(1) A lens joined body manufacturing method for joining a lens to a frame to obtain a lens joined body,
Between the frame and the lens, a low melting glass having a thermal expansion coefficient between the thermal expansion coefficient of the frame and the thermal expansion coefficient of the lens is interposed,
A method of manufacturing a lens joined body, wherein the frame and the lens are joined by the low-melting glass by heating the low-melting glass.

  As a result, the difference between the thermal expansion coefficient of the low melting point glass and the thermal expansion coefficient of the lens, the difference between the thermal expansion coefficient of the low melting point glass and the thermal expansion coefficient of the frame body is relatively small, and the melting point of the low melting point glass Therefore, the lens and the frame can be easily joined to each other while preventing damage to the lens and the frame at a relatively low temperature, and the low melting point glass has excellent chemical resistance. As a result, the airtightness and durability of the joint between the lens and the frame can be made excellent.

  (2) The method for producing a lens joined body according to (1), wherein the softening point of the low-melting glass is 300 to 700 ° C.

  Thereby, while suppressing the heating temperature in the said heating comparatively low, the airtightness and durability of the junction part of the lens and frame which are obtained can be made more excellent.

  (3) The method for producing a lens joined body according to (1) or (2), wherein a temperature reached by the low-melting glass by the heating is higher by 10 to 250 ° C. than a softening point of the low-melting glass.

  Thereby, a lens and a frame can be joined, preventing damage to a lens or a frame certainly. As a result, the airtightness and durability of the joint between the lens and the frame can be made more excellent.

  (4) The method for producing a lens joined body according to any one of (1) to (3), wherein the low-melting glass is made of a material that does not contain lead.

  Thereby, since lead is not included as a component of the low melting point glass, the safety of the lens joined body against the human body at the time of use can be further increased.

  (5) The lens joined body according to any one of (1) to (4), wherein the low-melting-point glass has a thermal expansion coefficient approximately halfway between the thermal expansion coefficient of the frame and the thermal expansion coefficient of the lens. Manufacturing method.

  As a result, even if the difference between the thermal expansion coefficient of the lens and the thermal expansion coefficient of the frame is relatively large, the difference between the thermal expansion coefficient of the low melting glass and the thermal expansion coefficient of the lens, The difference between the thermal expansion coefficient and the thermal expansion coefficient of the frame is lower. As a result, the airtightness and durability of the joint between the lens and the frame can be made more excellent.

(6) The method for producing a lens joined body according to any one of (1) to (5), wherein the low-melting glass has a thermal expansion coefficient of 30 × 10 ^{−7 to} 100 × 10 ⁻⁷ ° C. ⁻¹ .

  Thereby, it can respond to various thermal expansion coefficients as a thermal expansion coefficient of the material which comprises a lens or a frame. As a result, the airtightness and durability of the joint between the lens and the frame can be more reliably improved.

(7) The lens joined body according to any one of (1) to (6), wherein a difference between a thermal expansion coefficient of the lens and a thermal expansion coefficient of the frame is 30 × 10 ⁻⁷ ° C. ⁻¹ or less. Manufacturing method.

  Thereby, the stress which arises in low melting glass between a lens and a frame can be reduced more. As a result, the airtightness and durability of the joint between the lens and the frame body are further improved.

  (8) The method for manufacturing a lens joined body according to any one of (1) to (7), wherein the frame includes Fe and includes at least one of Ni and Co as a component.

  As a result, the material constituting the frame body has a thermal expansion coefficient similar to that of the material constituting the lens in a wide temperature range, and the stress generated in the low melting point glass between the lens and the frame body can be further reduced. it can. As a result, the airtightness and durability of the joint between the lens and the frame body are further improved.

  (9) The method for manufacturing a lens joined body according to any one of (1) to (8), wherein the lens is mainly made of borosilicate glass.

  This makes it possible to make the material constituting the lens similar in thermal expansion coefficient to the material constituting the frame in a wide temperature range, and to further reduce the stress generated in the low melting point glass between the lens and the frame. it can. As a result, the airtightness and durability of the joint between the lens and the frame body are further improved.

  (10) A lens joined body obtained by the manufacturing method according to any one of (1) to (9).

  Thereby, it is possible to obtain a lens joined body having excellent airtightness and durability at the joined portion between the lens and the frame.

(11) A lens joined body in which a lens is joined to a frame,
The frame and the lens are bonded via an adhesive layer made of low melting glass having a thermal expansion coefficient between the thermal expansion coefficient of the frame and the thermal expansion coefficient of the lens. A lens assembly characterized by the above.

  Thereby, it is possible to obtain a lens joined body having excellent airtightness and durability at the joined portion between the lens and the frame.

  (12) An endoscope comprising the lens joined body according to (10) or (11).

  Thereby, the endoscope excellent in the airtightness and durability of the joint between the lens and the frame can be obtained.

  According to the above-described present invention, it is possible to provide a method for manufacturing a lens joined body, a lens joined body, and an endoscope, which can make the airtightness and durability of the joined portion between the lens and the frame body excellent.

  Hereinafter, an endoscope manufacturing method and an endoscope according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

  1 is an overall view showing an embodiment of the endoscope of the present invention, FIG. 2 is a longitudinal sectional view showing the vicinity of a connecting portion between a distal end member and a bending portion of the endoscope shown in FIG. 1, and FIG. It is a figure (longitudinal sectional view) for demonstrating the manufacturing method of the lens joined body of this invention. In the following description, the right side in FIG. 1 is “one end”, the left side is “other end”, the lower side (left side in FIGS. 2 to 3) is “tip”, and the upper side (in FIGS. 2 to 3). The right side) is called the “base”. Further, in a part of the figure, the endoscope internal parts are omitted.

First, the overall configuration of the endoscope of the present invention will be described.
An endoscope (electronic scope) 1 shown in FIG. 1 includes an insertion portion flexible tube (endoscope flexible tube) 2 and an operation portion 3 connected to the proximal end side of the insertion portion flexible tube 2. A bending portion 4 connected to the distal end side of the insertion portion flexible tube 2, a distal end member (frame body) 9 connected to the distal end side of the bending portion 4, a light source insertion portion 5 to be inserted into the light source processor device, A connecting portion flexible tube (flexible tube for endoscope) 6 for connecting the operation portion 3 and the light source insertion portion 5 is provided. Hereinafter, the configuration of each unit will be described.

  The insertion portion flexible tube 2, the bending portion 4, and the tip member 9 constitute an insertion portion that is inserted into a living body lumen (tubular organ).

  Inside the insertion portion (inside the hollow portion) composed of the insertion portion flexible tube 2, the bending portion 4 and the tip member 9, there is an imaging means 11, a light guide 12 by an optical fiber bundle, a bending operation wire (not shown), a treatment. An instrument insertion channel tube (not shown), an air / liquid feeding tube (not shown) and the like are provided.

  As shown in FIG. 2, the imaging unit 11 includes an objective lens system (optical system) 112 and an imaging element (CCD) 111 installed on the base end side of the objective lens system 112, which are curved. It is installed in a hole 113 formed in the tip member 9 of the portion 4. In addition, an image signal cable 1111 disposed along the longitudinal direction of the insertion portion flexible tube 2 (and the connection portion flexible tube 6) is connected to the imaging element 111.

  In the present embodiment, the objective lens system 112 includes an objective lens (endoscope lens) 1120 including four lenses 1121 to 1124. Specifically, the objective lens system 112 includes a first lens 1121 installed at the distal end of the distal end member 9 and a central axis (light) from the first lens 1121 toward the proximal end side (image forming side). The objective lens 1120 includes a second lens 1122, a third lens 1123, and a fourth lens 1124 that are installed so that their axes substantially coincide with each other.

  The first lens 1121 is constituted by a plano-concave lens having a flat front end surface and a concave end surface (image forming side surface). The first lens 1121 is supported and fixed to the edge of the tip opening 1131 where the hole 113 opens at the tip of the tip member 9.

  The second lens 1122 is a plano-convex lens having a flat tip surface and a convex base surface.

The third lens 1123 and the fourth lens 1124 are composed of cemented lenses.
The second lens 1122, the third lens 1123, and the fourth lens 1124 are respectively joined to the cylindrical frame 1125 via adhesive layers 1129B to 1129D made of low-melting glass. In this state, the frame 1125 is inserted into the hole 113 and supported and fixed (joined) to the inside (hole 113) of the tip member 9 via a cylindrical spacer 1126.

  Note that a spacing ring 1127 that defines these spacings is interposed between the second lens 1122 and the third lens 1123.

  Further, an optical filter 1128 that removes a high frequency component from the reflected light guided to the light receiving surface of the image sensor 111 is fixed (fixed) to the distal end surface of the image sensor 111.

  As described above, in the present embodiment, the objective lens (endoscope lens) 1120, the frame body 1125 that is a member that respectively supports the objective lens (member that is joined thereto), the spacer 1126, the spacing ring 1127, An objective lens system (optical system) 112 is configured by a plurality of optical components such as the optical filter 1128.

  As a material which comprises each lens 1121-1124 (objective lens 1120), if it has the characteristic suitable as a lens, it will not specifically limit, Various glass materials can be used. Among these materials, those having similar thermal expansion characteristics over a wide temperature range to the materials constituting the frame body 1125, the tip member 9, or the adhesive layers 1129A to 1129D are preferable. For example, the material constituting each of the lenses 1121 to 1124 is preferably borosilicate glass. Thereby, for example, when the frame body 1125 and the tip member 9 include Fe and are composed of at least one of Ni and Co, etc., when manufacturing a lens joined body described later, an autoclave When exposed to high-temperature and high-pressure steam during processing or the like, the stress generated between the lenses 1121 to 1124 (objective lens 1120) and the frame 1125 or the tip member 9, that is, the adhesive layers 1129A to D can be more reliably reduced. . As a result, the airtightness and durability of the joint between each of the lenses 1121 to 1124 (objective lens 1120) and the frame body 1125 or the tip member 9 can be more reliably improved.

  Moreover, it is preferable that melting | fusing point of the glass which comprises each lens 1121-1124 is higher than melting | fusing point of the said low melting glass. As a result, when forming the adhesive layers 1129A to 1129D with low melting point glass as will be described later, the lenses 1121 to 1124, the tip member 9 and the frame 1125 are prevented from being deteriorated and the like. Can be joined.

  A material for forming the frame 1125 is not particularly limited, and various metal materials can be used. Among these materials, those having thermal expansion characteristics similar to those of the lenses 1122 to 1124 or the adhesive layers 1129B to D in a wide temperature range are preferable. For example, the material constituting the frame 1125 preferably contains Fe and contains at least one of Ni and Co as a component. Thus, for example, when the lenses 1122 to 1124 are made of borosilicate glass or the like, as described above, the lenses are used when a lens joined body described later is manufactured, or when exposed to high-temperature and high-pressure steam in an autoclave process or the like. The stress generated between 1122 to 1124 and the frame body 1125 can be more reliably reduced. As a result, the airtightness and durability of the joint between the lenses 1122 to 1124 and the frame body 1125 can be more reliably improved.

The difference between the thermal expansion coefficient of each of the lenses 1121 to 1124 and the thermal expansion coefficient of the frame 1125 or the tip member 9 is preferably 30 × 10 ⁻⁷ ° C.− ¹ or less, and preferably 10 × 10 ⁻⁷ ° C. More preferably, it is ⁻¹ or less. Thereby, the stress which arises in adhesive bond layer 1129A-D between the frame 1125 or the front-end | tip member 9, and each lens 1121-1124 is reduced more reliably. As a result, the airtightness and durability of the joints between the lenses 1121 to 1124 and the frame body 1125 or the tip member 9 can be more reliably improved.

  When the difference between these thermal expansion coefficients exceeds the upper limit, depending on the difference in dimensions between the lenses 1121 to 1124 and the frame 1125 or the tip member 9, the lens assembly described later may be manufactured. When exposed to high-temperature and high-pressure steam during autoclaving or the like, a relatively large stress may be generated at the joint.

  The adhesive layers 1129A to 1129D are obtained by melting and curing a low melting point glass interposed between the lenses 1121 to 1124 and the frame body 1125 by heating. The low melting point glass will be described in detail later.

  The insertion portion flexible tube 2 includes a spiral tube (not shown), a mesh tube (braided body) that covers the outer periphery of the spiral tube, and a skin that covers the periphery of the mesh tube. A hollow portion (lumen) is formed to accommodate the. Although it does not specifically limit as a constituent material of the said outer skin, For example, it can be used combining at least 1 sort (s) or 2 or more types among various resin which has flexibility, and various elastomers.

  As shown in FIG. 2, the bending portion 4 connected to the distal end of the insertion portion flexible tube 2 includes a plurality of node rings 41 that are rotatably connected to each other, and a mesh tube that is covered on the outer periphery of the node ring 41. 42 and an outer skin 43 coated on the outer periphery of the mesh tube. As will be described later, the bending portion 4 can be remotely operated from the operation portion 3 in the direction and degree of the bending. The constituent material of the outer skin 43 is not particularly limited, and for example, those exemplified as the constituent material of the outer skin of the insertion portion flexible tube 2 can be used.

Further, a tip member 9 is provided at the tip of the bending portion 4 (see FIG. 2).
As described above, inside the insertion portion (inside the hollow portion) composed of the insertion portion flexible tube 2, the bending portion 4 and the tip member 9, there is an imaging means 11, a light guide 12 by an optical fiber bundle, a bending operation wire (see FIG. (Not shown), a treatment instrument insertion channel tube (not shown), an air / liquid feeding tube (not shown), and the like.

  Near the distal end portion of the distal end member 9, a plano-concave lens 13, an objective lens 1120, a forceps (treatment instrument) channel (not shown), an air / liquid feeding port (not shown), and the like are provided. .

  The plano-concave lens 13 is joined to the tip member 9 via an adhesive layer 1129E made of low-melting glass, and the light emitted from the tip of the optical fiber constituting the light guide 12 is applied to the observation site (subject). It has the function of diffusing, uniforming and irradiating.

  The material constituting the plano-concave lens 13 is not particularly limited as long as it has characteristics suitable as a lens, and various glass materials and various resin materials can be used. Among these materials, those having similar thermal expansion characteristics over a wide temperature range to the materials constituting the tip member 9 and the adhesive layers 1129A and E are preferable. For example, the plano-concave lens 13 is preferably mainly composed of borosilicate glass. Thereby, for example, when the tip member 9 includes Fe and is composed of at least one of Ni and Co as a component, the above-described lenses 1121 to 1124 and the frame 1125 or the tip member 9 are used. Similarly to the joint portion, the airtightness and durability of the joint portion between the plano-concave lens 13 and the tip member 9 can be made more reliably excellent.

  The melting point of the glass constituting the plano-concave lens 13 is preferably higher than the melting point of the low melting point glass described above. Thereby, when forming adhesive layer 1129E with low melting glass so that it may mention later, planoconcave lens 13 and tip member 9 can be joined, preventing modification of planoconcave lens 13, etc.

  The objective lens 1120 has a function of guiding light reflected by the observation site (reflected light that forms a subject image) so as to form an image on the light receiving surface of the image sensor 111.

  It does not specifically limit as a material which comprises the front-end | tip member 9, Various metal materials etc. can be used. Among these materials, those having similar thermal expansion characteristics over a wide temperature range to the materials constituting the plano-concave lens 13 and the first lens 1121 are preferable. For example, it is preferable that the tip member 9 is made of a material containing Fe and containing at least one of Ni and Co as a component. Thereby, for example, when the plano-concave lens 13 and the first lens 1121 are made of borosilicate glass or the like, the plano-concave lens 13 and the first lens 1121 are similar to the joint portion between the frame 1125 and the lenses 1122 to 1124 described above. A lens joined body having excellent airtightness and durability at the joint between the tip member 9 and the tip member 9 can be obtained more reliably.

The difference between the thermal expansion coefficient of the plano-concave lens 13 and the first lens 1121 and the thermal expansion coefficient of the tip member 9 is the difference between the thermal expansion coefficient of the frame body 1125 and the thermal expansion coefficient of the lenses 1122 to 1124. Similarly, it is preferably 30 × 10 ⁻⁷ ° C.− ¹ or less, and more preferably 10 × 10 ⁻⁷ ° C.− ¹ or less. Thereby, the stress which arises between the front-end | tip member 9 and the plano-concave lens 13 and the 1st lens 1121 is reduced more reliably. As a result, the airtightness and durability of the joint portion between the plano-concave lens 13 and the first lens 1121 and the tip member 9 can be further improved.

  When the difference between these thermal expansion coefficients exceeds the upper limit, depending on the dimensional difference between the plano-concave lens 13, the first lens 1121, and the tip member 9, the following lens assembly may be manufactured. In addition, when exposed to high-temperature and high-pressure steam during autoclaving or the like, a relatively large stress may be generated in the joint.

  In the endoscope 1 of the present embodiment, the distal end member 9 (small diameter portion 91) is fixed to the outer skin 43. The tip member 9 (small diameter portion 91) and the outer skin 43 are preferably fixed in a liquid-tight manner.

  The proximal end portion of the insertion portion flexible tube 2 is connected (connected) to the operation portion 3. The operation unit 3 is a part that the operator holds and operates the entire endoscope 1, and includes a housing (housing) 31 and operation knobs 32 and 33. When the operation knobs 32 and 33 are operated, a bending operation wire (not shown) disposed in the insertion portion flexible tube 2 and the bending portion 4 is pulled, and the bending direction and the degree of bending of the bending portion 4 can be freely set. Can be operated.

  The light source insertion part 5 and the connection part flexible tube 6 comprise the connection part with respect to a light source processor apparatus (not shown).

  The light source insertion portion 5 includes a casing 53, an image signal connector 51, and a light source connector 52. By inserting the image signal connector 51 and the light source connector 52 into the light source processor device, the endoscope 1 is electrically and optically connected to the light source processor device. The light source processor device is connected to a monitor device (not shown) via a cable.

  The connection portion flexible tube 6 is a long object having flexibility, and is provided so as to connect the operation portion 3 and the light source insertion portion 5.

  The connecting portion flexible tube 6 is a long object having flexibility (elasticity), and has substantially the same configuration as the insertion portion flexible tube 2 described above.

  The light emitted from the light source in the light source processor device is continuously arranged in the light source insertion portion 5, the connection portion flexible tube 6, the operation portion 3, the insertion portion flexible tube 2, and the bending portion 4. Through the light guide 12 provided, the observation site is irradiated from the distal end portion of the distal end member 9 via the plano-concave lens 13 and illuminated.

  The reflected light (subject image) from the observation site illuminated by the illumination light is imaged by the image sensor (CCD) 111. An image signal corresponding to the subject image captured by the image sensor 111 is output via a buffer (not shown).

  This image signal is continuously arranged in the insertion portion flexible tube 2, the operation portion 3, and the connection portion flexible tube 6, and an image signal cable 1111 that connects the image sensor 111 and the image signal connector 51. Then, the light is transmitted to the light source insertion unit 5.

  Then, predetermined processing (for example, signal processing, image processing, etc.) is performed in the light source insertion unit 5 and the light source processor device, and then input to the monitor device. In the monitor device, an image (electronic image) captured by the image sensor 111, that is, a video endoscope monitor image is displayed.

  As described above, in the endoscope 1 of the present embodiment, the low-melting glass (adhesive layer 1129A, E) is interposed between the plano-concave lens 13, the first lens 1121 and the tip member 9, and this low The plano-concave lens 13, the first lens 1121 and the tip member 9 are joined by melting point glass. Similarly to this, the lenses 1122 to 1124 and the frame body 1125 are joined by a low melting point glass. The present invention is characterized by such a joint and a method for forming the joint. Hereinafter, the method of forming the joint will be described in detail with reference to FIG. In the following description, a joint portion between the tip member (frame body) 9 and the plano-concave lens 13 will be described as a joint portion, but a joint portion between the tip member 9 and the first lens 1121, lenses 1122 to 1124 and a frame body 1125. The same is true for the joint portion and the like.

(Production method of lens assembly)
In the present embodiment, an adhesive supply step for supplying low melting point glass as an adhesive between the tip member 9 and the plano-concave lens 13 and a heating step for heating and melting the low melting point glass are sequentially performed. The tip member 9 and the plano-concave lens 13 are joined. Hereinafter, details of each process will be described in order.

<Adhesive supply process>
First, as shown in FIG. 3A, a low-melting glass 1129E ′ is supplied between the tip member 9 and the plano-concave lens 13 (gap).

  The tip member 9 can be formed by a known processing method such as pressing or cutting. Further, for example, it is preferable to anneal the tip member 9 before joining with the plano-concave lens 13 as necessary to remove the residual stress generated in the tip member 9 during the processing. Thereby, the stress which arises between the front-end | tip member 9 and the plano-concave lens 13 after the below-mentioned welding process can be reduced, and it can prevent reliably that the junction part of the front-end | tip member 9 and the plano-concave lens 13 is cracked by the said stress. Since the contamination and alteration that occurs at the joining portion of the tip member 9 vary depending on the processing method and the shape of the tip member 9, this annealing is contaminated and altered at the joining portion of the tip member 9 depending on the processing method and the shape of the tip member 9. Is preferably removed.

  In order to supply the low melting point glass between the tip member 9 and the plano-concave lens 13 (gap), in this embodiment, at least one of these at the joint between the tip member 9 and the plano-concave lens 13 is a low melting point glass. Then, the plano-concave lens 13 is inserted into the tip opening 1131 of the tip member 9. In this case, the form of the low-melting glass is not particularly limited as long as the low-melting glass can be supplied between the tip member 9 and the plano-concave lens 13 (gap), but it is liquid (highly fluid), semi-solid. , Granular, small lump (pellet), powder, flakes and the like.

  The softening point of the low melting point glass is preferably 300 to 700 ° C, more preferably 300 to 500 ° C. As a result, the heating temperature in the heating step described later can be kept relatively low, and the airtightness and durability of the joint portion between the plano-concave lens 13 and the tip member 9 in the obtained lens joined body can be made more excellent. .

The material constituting the low-melting glass is not particularly limited as long as it has a relatively low melting point as glass, can join the plano-concave lens and the tip member, and is resistant to high-temperature and high-pressure steam. Examples thereof include low-melting glass such as Bi—Si—B, SiO ₂ —B ₂ O ₂ .RO, B ₂ O ₃ .PbO, and B ₂ O ₃ .PbO.ZnO.

  The thermal expansion coefficient adjusting agent is not particularly limited as long as the thermal expansion coefficient of the low melting point glass can be adjusted to a desired value by adjusting the content of the thermal expansion coefficient adjusting agent in the low melting point glass.

<Heating process>
Next, as described above, the low melting point glass supplied (intervened) between the tip member 9 and the plano-concave lens 13 is heated and cured to form an adhesive layer 1129E as shown in FIG. To do.

  Although it does not specifically limit as the method of the said heating in this process, For example, the heating by an electric furnace etc. is mentioned. Such heating is preferably performed in a non-oxidizing atmosphere.

  The heating in this step may be performed by heating and melting the low melting point glass so that the tip member 9 and the plano-concave lens 13 can be joined. However, the tip member 9 and the plano-concave lens together with the low melting point glass may be used. It is preferable to heat 13 as a whole. Thereby, it is possible to prevent the residual stress from being generated in the tip member 9 and the plano-concave lens 13.

  Moreover, it is preferable that the temperature which the said low melting glass reaches by the said heating is 10 to 250 degreeC or more high temperature from the softening point of a low melting glass. In other words, the temperature is preferably lower than the melting point and softening point of the plano-concave lens 13 and the tip member 9 while melting the low-melting glass. Thereby, the plano-concave lens 13 and the tip member 9 can be joined while reliably preventing damage to the plano-concave lens 13 and the tip member 9. As a result, the airtightness and durability of the joint between the plano-concave lens 13 and the tip member 9 can be further improved.

  The cured low-melting glass (adhesive layer 1129E) has a thermal expansion coefficient between the thermal expansion coefficient of the tip member 9 and the thermal expansion coefficient of the plano-concave lens 13. Thereby, the difference between the thermal expansion coefficient of the low melting point glass and the thermal expansion coefficient of the plano-concave lens 13 and the difference between the thermal expansion coefficient of the low melting point glass and the thermal expansion coefficient of the tip member 9 become relatively small. As a result, the airtightness and durability of the joint between the plano-concave lens 13 and the tip member 9 in the obtained lens joined body can be made excellent. Further, since the low melting point glass has a relatively low melting point, the heating temperature can be set to a relatively low temperature in the heating process described later, and the plano-concave lens 13 can be easily prevented while preventing damage to the plano-concave lens 13 and the tip member 9. And the tip member 9 can be joined.

  In particular, the thermal expansion coefficient of the low-melting glass is preferably approximately halfway between the thermal expansion coefficient of the tip member 9 and the thermal expansion coefficient of the planoconcave lens 13. Thereby, even when the difference between the thermal expansion coefficient of the plano-concave lens 13 and the thermal expansion coefficient of the tip member 9 is relatively large, the thermal expansion coefficient of the low-melting glass (adhesive layer 1129E) and the heat of the plano-concave lens 13 are increased. The difference between the expansion coefficient and the difference between the thermal expansion coefficient of the low-melting glass (adhesive layer 1129E) and the thermal expansion coefficient of the tip member 9 becomes smaller. As a result, the airtightness and durability of the joint between the plano-concave lens 13 and the tip member 9 can be further improved.

Specifically, the thermal expansion coefficient of the low-melting glass is preferably from ^{30 × 10 -7 ~100 × 10 -7} ℃ -1, at ^{40 × 10 -7 ~70 × 10 -7} ℃ -1 More preferably. Thereby, various thermal expansion coefficients can be handled as the thermal expansion coefficients of the materials constituting the plano-concave lens 13 and the tip member 9. As a result, the airtightness and durability of the joined portion between the plano-concave lens 13 and the tip member 9 in the obtained lens joined body can be more reliably improved.

The melting point of the glass constituting the plano-concave lens 13 is preferably lower than the heating temperature described above. Thereby, in the case of the above-mentioned heating, alteration of the plano-concave lens 13 etc. can be prevented.
Thus, the tip member 9 is joined to the plano-concave lens 13 by the low melting point glass.

  As described above, the method for manufacturing a lens assembly, the lens assembly, and the endoscope of the present invention have been described, but the present invention is not limited thereto.

  For example, the endoscope of the present invention is not limited to that of the above-described embodiment, and each unit constituting the endoscope can be replaced with any configuration that can exhibit the same function.

  In the above-described embodiments, the electronic endoscope has been described. However, the present invention can be applied to various endoscopes including a fiber endoscope.

  Further, the joining of the lens and the frame body with the low melting point glass as described above is not limited to the above-described part, and may be any part. For example, the eyepiece lens and its frame may be joined by low melting point glass as described above.

  Moreover, although embodiment mentioned above is an endoscope used for medical use, this invention is not limited to this, The endoscope used for industrial use etc. may be sufficient.

Next, specific examples of the present invention will be described.
1. Production of endoscope (Example 1)
First, an alloy material (Fe—Ni—Co alloy) of 54 wt% Fe-29 wt% Ni-17 wt% Co is cut to obtain frame bodies having shapes such as the tip member 9 and the frame body 1125 shown in FIG. It was.

  Thereafter, each frame was held at 900 ° C. for 1 hour under an inert gas atmosphere and then held at 100 ° C. for 15 minutes. Thereafter, a surface treatment (pretreatment) for degreasing the frame was performed.

Next, SiO ₂ —B ₂ O ₃ .RO-based low-melting glass was adhered to the lens bonding portion in each frame so as to have an average thickness of 100 μm. The low-melting glass had a granular shape and an average particle size of 50 μm. The softening point of the low-melting glass was about 600 ° C.

  Then, a lens made of borosilicate glass (transition point 490 ° C.) having shapes such as the plano-concave lens 13 and the lenses 1121 to 1124 shown in FIG. 2 is incorporated in each corresponding part of each frame, and the low melting point glass is obtained. It was interposed between the lens and each frame. At this time, the lens and the frame were formed and held so as to form a 100 μm gap between the lens and the frame.

  Thereafter, the entire glass having the low melting point interposed between the lens and the frame is heated to 500 ° C. by an electric furnace in an inert gas atmosphere, and then each frame is cooled at a cooling rate. Cooling (slow cooling) was performed at 10 ° C./min to obtain each frame to which the lens was bonded, that is, a lens bonded body. At this time, the low-melting glass was melted by the heating and then cured by the cooling to join the lens and the frame.

In the above-described lens joined body, the thermal expansion coefficient of each lens is 46 × 10 ⁻⁷ ° C.− ¹ , and the thermal expansion coefficient of each frame is 54 × 10 ⁻⁷ ° C.− ^1. The average thermal expansion coefficient of the melting point glass was 52 × 10 ⁻⁷ ° C. ⁻¹ .

  Next, an electronic endoscope (upper digestive tract endoscope) as shown in FIG. 1 was manufactured using such a lens joined body.

(Example 2)
A lens joined body was produced in the same manner as in Example 1 except that Bi-Si-B based low melting point glass was used as the low melting point glass, and an electronic endoscope was produced using this lens joined body. . The average thermal expansion coefficient of the low-melting glass after curing was 44 × 10 ⁻⁷ ° C. ⁻¹ . The softening point of the low-melting glass was about 500 ° C.

(Examples 3 to 5)
A lens joined body was manufactured in the same manner as in Example 1 except that the low melting point glass, the frame, and the constituent materials of the lens were as shown in Table 1, and an electronic endoscope was manufactured using this lens joined body. . The softening point of the low-melting glass was about 600 ° C.

(Comparative example)
First, a frame having the same components as in Example 3 was pretreated in the same manner as in Example 1.

  Next, a lens similar to that of Example 3 was incorporated into each corresponding portion of each frame, and an epoxy adhesive was poured between the lens and each frame.

  Thereafter, the whole of the lens and the frame having the adhesive interposed therebetween is heated to 100 ° C. by an electric furnace in an inert gas atmosphere, and then each frame is cooled at a cooling rate of 10 ° C. Each frame body to which the lens was bonded, that is, a lens bonded body, was obtained by cooling (gradual cooling) at a temperature of ° C / minute.

  Next, an electronic endoscope (an upper gastrointestinal tract endoscope) as shown in FIG. 1 was manufactured using this lens assembly.

(Reference example)
A lens and a frame made of the same borosilicate glass as in Example 3 were made of SUS304 (thermal expansion coefficient 173 × 10 ⁻⁷ ° C.- ¹ with SiO ₂ —B ₂ O ₃ .RO-based low melting glass (expansion coefficient 120 × 10 ^{− A} lens joined body was manufactured in the same manner as in Example 1 except that the adhesive was bonded at ⁷ ° C. ⁻¹ ), and an electronic endoscope was manufactured using the lens joined body.

[Evaluation]
2-1 Evaluation of high-temperature and high-pressure steam resistance Each of the electronic endoscopes produced in each of the examples and comparative examples was autoclave sterilized (atmospheric pressure: about 2 atm, temperature 132 ° C., sterilization time: 5 minutes) 200 times. went.

Then, after each sterilization treatment for each electronic endoscope, the fogging of the lenses of the first lens and each projection lens was visually observed and evaluated according to the following four criteria.
A: No fogging of the lens is observed even after 200 sterilization treatments.
○: Slight fogging of the lens was observed after 200 sterilization treatments.
(Triangle | delta): The cloudiness of the lens was recognized from about 100 times of sterilization processes.
X: A crack of the lens was observed from about 100 sterilization treatments.

2-2 Hydrogen peroxide resistance evaluation Each endoscope obtained in each example and comparative example was immersed for 60 minutes in a 30 wt% aqueous hydrogen peroxide solution (liquid temperature: 25 ° C.) placed in a container. Thereafter, each endoscope was taken out from the container, and left in an atmosphere of temperature: 25 ° C. and humidity: 60% RH for 30 minutes.

The above operation (immersion of the solution, standing outside the solution) was repeated 5000 times.
Thereafter, the appearance at the bonded portion of each endoscope was evaluated according to the following four-stage criteria.
A: Appearance change is not recognized.
○: Slight discoloration or coloring is observed.
Δ: Discoloration or coloring is clearly recognized.
X: Deterioration of the bonded portion is remarkable, and fixing by bonding is impossible. Or, deformation and deterioration of the outer skin and the like are remarkably unsuitable for use as an endoscope.
These results are shown in Table 2.

  Regarding the high temperature and high pressure steam resistance evaluation, as shown in Table 2, the electronic endoscopes of Examples 1 to 5 (endoscopes of the present invention) were all found to be cloudy after 200 sterilization treatments. I couldn't. This indicates that the bonding state between each lens and the frame body is kept good, and there is no intrusion of water vapor into the inside of the electronic endoscope.

On the other hand, in the electronic endoscope of the comparative example, the fogging of the lens was recognized at an early stage, and the lens dropped out of the frame body after 200 sterilization treatments.
In the reference example, since the difference in thermal expansion coefficient between the lens and the frame was too large, the lens cracked.

  Moreover, regarding the hydrogen peroxide resistance evaluation, as is clear from Table 2, the endoscopes of Examples 1 to 5 all had excellent resistance to hydrogen peroxide.

  On the other hand, the endoscope of the comparative example was inferior in resistance to hydrogen peroxide as compared with the endoscope of the present invention.

It is a general view which shows an electronic endoscope (electronic scope) provided with the lens joined body of this invention. It is a longitudinal cross-sectional view which shows the front-end | tip part of the insertion part flexible tube of the electronic endoscope shown in FIG. It is a figure (longitudinal sectional view) for demonstrating the manufacturing method of the lens joined body of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Endoscope 12 Light guide 13 Plano-concave lens 2 Insertion part flexible tube 3 Operation part 31 Housing 32, 33 Operation knob 4 Bending part 41 Node ring 42 Reticulated tube 43 Outer skin 5 Light source insertion part 51 Image signal connector 52 For light sources Connector 53 Casing 6 Connection portion Flexible tube 9 Tip member 91 Small diameter portion 11 Imaging means 111 Imaging device (CCD)
1111 Image signal cable 112 Objective lens system 1120 Objective lens 1121 First lens 1122 Second lens 1123 Third lens 1124 Fourth lens 1125 Frame 1126 Spacer 1127 Spacing ring 1128 Optical filter 1129A to 1129E Adhesive layer 1129E ′ Low melting point glass 113 Hole 1131 Tip opening

Claims (12)

A method for manufacturing a lens joined body, in which a lens is joined to a frame to obtain a lens joined body,
Between the frame and the lens, a low melting glass having a thermal expansion coefficient between the thermal expansion coefficient of the frame and the thermal expansion coefficient of the lens is interposed,
A method of manufacturing a lens joined body, wherein the frame and the lens are joined by the low-melting glass by heating the low-melting glass.   The method of manufacturing a lens joined body according to claim 1, wherein a softening point of the low-melting glass is 300 to 700 ° C.   The method for producing a lens joined body according to claim 1 or 2, wherein a temperature reached by the low-melting glass by the heating is 10 to 250 ° C or more higher than a softening point of the low-melting glass.   The method for producing a lens joined body according to any one of claims 1 to 3, wherein the low-melting glass does not contain lead as a material constituting the low-melting glass.   5. The method of manufacturing a lens joined body according to claim 1, wherein the low-melting glass has a thermal expansion coefficient that is substantially between the thermal expansion coefficient of the frame body and the thermal expansion coefficient of the lens. 6. The method for manufacturing a lens joined body according to claim ¹ , wherein the low-melting glass has a thermal expansion coefficient of 30 × 10 ^{−7 to} 100 × 10 ⁻⁷ ° C. ⁻¹ . The method for manufacturing a lens joined body according to any one of claims 1 to 6, wherein a difference between a thermal expansion coefficient of the lens and a thermal expansion coefficient of the frame is 30 x ^10-7 ° C- ¹ or less.   The method of manufacturing a lens joined body according to any one of claims 1 to 7, wherein the frame includes Fe and includes at least one of Ni and Co as a component.   The method of manufacturing a lens joined body according to any one of claims 1 to 8, wherein the lens is mainly made of borosilicate glass.   A lens joined body obtained by the manufacturing method according to claim 1. A lens joined body in which a lens is joined to a frame,
The frame and the lens are bonded via an adhesive layer made of low melting glass having a thermal expansion coefficient between the thermal expansion coefficient of the frame and the thermal expansion coefficient of the lens. A lens assembly characterized by the above.   An endoscope comprising the lens cemented body according to claim 10 or 11.

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