JP2003230534A - Endoscopic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endoscopic apparatus which is not required to increase the number of parts or an assembling man-hour in securing autoclave resistance in sterilization and is capable of avoiding an occurrence of flare and ghost due to the incident light through the forefront cover glass that reflects on an inner periphery of a penetrating hole of a lens frame. <P>SOLUTION: A plating portion to improve dip-solderability is provided on an inner periphery and bottom surface of a concave 22 of the forefront lens frame 21, while a portion 29 for blackening procedure is provided with an inner periphery of a hole 24 of the lens frame 21 to prevent flare and ghost due to the light reflected thereon. The forefront lens 23 coated with a flexibilizer is arranged in the concave 22 of the lens frame 21, and a solder is filled in a space between the forefront lens 23 and the concave 22 of the lens frame 21 from around an outer periphery of a leading edge of the forefront lens 23 so that the solder fillet 7a is formed over an entire periphery of the basic edge of the forefront lens 23 permitting the forefront lens 21 to be hermetically connected with the concave 22a of the lens frame 21. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope apparatus compatible with autoclave sterilization (high-pressure, high-temperature, high-temperature steam sterilization). 2. Description of the Related Art Endoscopes, which can be inserted into a body cavity or the like to observe a deep part inside the body cavity or perform a medical treatment or the like by using a treatment tool as needed, are widely used in the medical field. ing. For endoscopes used in the medical field, it is indispensable to surely sterilize and sterilize an endoscope once used in order to prevent infectious diseases and the like. Recently, autoclave sterilization, which can be used immediately after sterilization without complicated operations and has low running cost, is becoming mainstream in the field of endoscopes. [0004] In this autoclave sterilization, an object to be sterilized is exposed to high-temperature steam of about 120 ° C to 135 ° C under high pressure to sterilize it. At this time, the high-pressure steam permeates almost all polymer materials such as resin, rubber, and resin adhesive.
For this reason, during autoclave sterilization, water vapor penetrates into the endoscope, and water vapor penetrates into the imaging unit in which the objective lens, the solid-state imaging device, the substrate, the signal line, the signal cable, and the like are arranged, resulting in electrical shortage. There was a possibility that a serious problem would occur. In order to prevent the steam from the autoclave sterilization from entering the imaging unit, the present applicant has
Japanese Patent Application No. 2000-25566 shows an endoscope in which a lens frame is covered with a metal frame to which a front cover glass is soldered and fixed, and a base end of the metal frame is welded by laser irradiation to form an airtight structure. [0006] However, in the endoscope disclosed in Japanese Patent Application No. 2000-25566, a metal frame, a pipe member, and the like are required in addition to a lens frame and an element frame to constitute an imaging unit. With such a structure, not only the number of parts increases, but also the assemblability deteriorates and the imaging unit becomes large. The present invention has been made in view of the above circumstances, and does not increase the number of parts or the number of assembling steps in order to ensure resistance to autoclave sterilization. It is an object of the present invention to provide an endoscope apparatus capable of preventing a flare or a ghost due to reflection on the inner peripheral surface of the through hole and obtaining a good observation image. [0008] In order to achieve the above object, an endoscope apparatus according to the present invention has a concave portion on the distal end side and a through-hole penetrating the bottom surface portion and the proximal end side of the concave portion. A lens frame comprising: a plating portion covering an inner surface of a concave portion of the lens frame; a distal lens disposed in the concave portion of the lens frame; and a distal end lens and the lens frame disposed in the concave portion of the lens frame. A solder portion provided between the plating portion that covers the inner surface of the concave portion, and light that is provided on the inner peripheral surface of the through hole of the lens frame and is incident from the front lens and passes through the through hole. And an antireflection section for preventing reflection on the inner peripheral surface. Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 relate to a first embodiment of the present invention. FIG. 1 is a view for explaining the configuration of an imaging unit of an endoscope, FIG. 2 is a view for explaining a lens frame, and FIG. It is a figure explaining the relation with a spacing member. As shown in FIG. 1, an imaging unit 1 for an endoscope
Is composed of an objective lens unit 2 that forms an observation optical system, a CCD 3 that is a solid-state imaging device having an imaging surface arranged at a focal position of the objective lens unit 2, and a circuit board 4 that is electrically connected to the CCD 3. It is mainly composed. The signal lines 5 are electrically connected to the terminal portions 4a of the circuit board 4, respectively, and these signal lines 5 are inserted through the signal cable 6 and connected to a video processor (not shown). ing. The objective lens unit 2 includes a lens frame 21 having a substantially convex shape, a front end lens 23 hermetically bonded to a predetermined position of a concave portion 22 formed at the front end portion of the lens frame 21, A proximal lens group 26 composed of a plurality of lenses 25, a spacing ring 25b, a diaphragm 25c, and the like disposed in the hole 24 communicating with the front end lens 23 and the distal lens 23 and the proximal lens group 26. It is mainly composed of a substantially pipe-shaped spacing member 27 disposed between the first lens 25a disposed behind the lens 23. The CCD 3 is arranged such that the imaging surface is integrally fixed to the base end surface of a cover glass 32 fixed to the base end of the element frame 31. For this reason, the light beam that has passed through the distal lens 23 and the proximal lens group 26 of the objective lens unit 2 passes through the cover glass 32 and forms an image on the imaging surface of the CCD 3. As shown in FIG. 2, a plating portion 28 such as Ni, for example, for improving the wettability of solder is provided on the inner side surface and the bottom surface of the concave portion 22 of the lens frame 21 as indicated by thick solid lines in the drawing. It is. On the other hand, a portion of the inner peripheral surface of the hole portion 24 of the lens frame 21 indicated by a thick broken line in the drawing is used to prevent flare and ghost due to reflection on the inner peripheral surface, for example, B
A black processing part 29 of -Cu is provided. The plating section 28 and the black processing section 29 may be provided by forming the lens frame 21 by machining and then masking the plating section 28 and the black processing section 29 to provide them separately. There is a method in which the plated portion 28 is provided at the stage when the concave portion 22 is formed by machining, the hole portion 24 is formed, the plated portion 28 is masked, and the black processing portion 29 is provided in the hole portion 24. A method of assembling the objective lens unit 2 will be described with reference to FIG. As shown in the figure, when assembling the objective lens unit 2, first, a tip lens 23 coated with, for example, a flux as an oxidizing agent used for activating solder on the outer peripheral surface is arranged in the concave portion 22 of the lens frame 21. At this time, the base end surface of the front lens 23 is brought into contact with the bottom surface 22 a of the concave portion 22. Next, in order to position the tip lens 23 in the axial direction, the tip lens 23 is brought into contact with the base end face 21a of the lens frame 21 to project from the bottom face 22a of the recess 22 by a predetermined dimension, for example, as shown by a two-dot chain line. The tool 40 is inserted into the hole 24 from the hole opening 24a. A space is formed at a predetermined interval between the base end surface 23a of the tip lens 23 and the bottom surface 22a of the recess 22.
The solder 7 is poured between the front end lens 23 and the lens frame 21 from the outer periphery on the front end side. When the solder fillet 7a is formed over the entire circumference of the base lens of the tip lens 23, the pouring of the solder 7 is stopped and the solder 7 waits for the solder 7 to harden.
When the solder 7 is solidified, the tip lens 2
3 is hermetically bonded and fixed at a position separated from the bottom surface 22a of the concave portion of the lens frame 21 by a predetermined distance. Next, the jig 40 is removed, and the base surface of the front lens 23 and the inner surface of the lens frame 21 are washed to remove the flux and impurities. Thereafter, the spacing member 27 and the base lens group 26 are inserted in the hole 24 from the hole opening 24a in this order, and the base lens group 26 is disposed at a predetermined position. Then, the lens 25 located at the rearmost end of the base lens group 26 is bonded and fixed to the lens frame 21. Thus, the objective lens unit 2 is completed. The dimension from the distal lens 23 to the proximal lens group 26 can be changed by adjusting the length of the spacing member 27. Here, the hermetic joining between the lens frame 21 and the element frame 31 will be described. When the lens frame 21 and the element frame 31 are integrally and air-tightly joined, first, the positional relationship between the lens frame 21 and the element frame 31 is adjusted to adjust the focus. Then, the lens frame 21 and the element frame 31 are hermetically bonded and fixed by laser welding in this bonded state. Therefore, as shown in FIG. 2, the lens frame 21 is provided with an element frame arrangement portion 21b in which the tip of the element frame 31 is extrapolated. The element frame arrangement portion 21b has a large-diameter portion 21c serving as a welding joint and a small-diameter portion 21d serving as a bonding joint. On the other hand, as shown in FIG.
A large-diameter hole portion 31c extrapolated to 1c and a small-diameter hole portion 31d extrapolated to the small-diameter portion 21d are provided. For this reason, in this embodiment, the small-diameter portion 21d of the lens frame 21 with the adhesive 34 applied to the outer peripheral surface is
Focus adjustment is performed with the element frame 31 inserted into the small-diameter hole 31d. After the adhesive 34 is cured, a portion indicated by an arrow A, for example, which is separated from the bonding portion is irradiated with laser light to be hermetically bonded and fixed by welding. Reference numeral 41 denotes a reinforcing frame externally arranged on the base end side of the element frame 31. Reference numeral 42 denotes a resin insulating tube that covers the entire reinforcing frame 41 and the end of the signal cable 6 so that the reinforcing frame 41 is not exposed. The space surrounded by the reinforcing frame 41 and the insulating tube 42 is filled with an adhesive 43 having low vapor permeability. As described above, by providing a space at a predetermined interval between the base end surface of the front lens and the bottom surface of the hole formed in the lens frame, the oxidizing agent and impurities can be easily cleaned after the hermetic bonding by soldering. It can be carried out. In addition, at the time of joining by soldering, by providing a space portion at a predetermined interval, the solder fillet can be formed over the entire circumference of the base lens side of the front lens without the solder flowing into the hole. As a result, the assembling strength and airtightness of the front lens to the lens frame are further ensured. Further, in order to join the lens frame and the element frame, the joint for welding and the joint for bonding are separated and separated by a step, so that the adhesive is avoided while avoiding the heat affected range of laser welding. The coating can be performed, and the laser welding can be reliably performed without defocusing after the focus adjustment. As a result, the autoclave resistance is increased without increasing the number of parts and the number of assembly steps,
An imaging unit of the endoscope that can obtain a good observation image is configured. FIG. 4 is a view for explaining another configuration of the imaging unit of the endoscope according to the second embodiment of the present invention. As shown in the figure, in the present embodiment, the large-diameter portion 21c provided on the element frame arrangement portion 21b of the lens frame 21 is used as a bonding joint, and the small-diameter portion 21d is used as a welding joint. For this reason, in the present embodiment, focus adjustment is performed with the large diameter portion 21c of the lens frame 21 with the adhesive 34 applied to the outer peripheral surface inserted into the large diameter hole 31c of the element frame 31. The arrow A separated from the bonding portion after the adhesive 34 has hardened.
A laser beam is applied to the part shown in (1) and hermetically joined and fixed by welding. Reference numeral 35 denotes a pool provided between the base end of the large-diameter portion 21c and the tip end of the small-diameter hole 31d, and the adhesive 34 is stored as shown in the drawing. In this embodiment, the spacing member 2
A narrowing portion 27a having a relatively small inner diameter is integrally provided on the tip side of 7A, and a black processing portion 29 is provided on the inner peripheral surface. Other configurations are the same as those of the first embodiment,
The same members are denoted by the same reference numerals and description thereof will be omitted. As described above, since the bonding portion for bonding the lens frame and the element frame is provided on the distal end side from the laser welded portion, the adhesive is erroneously welded when the lens frame is inserted and arranged in the element frame. It can be prevented from adhering to the part. This makes it easier to apply the adhesive while avoiding the heat affected area of laser welding. Further, by providing the aperture member with the aperture portion, the reflected light from the plated portion of Ni or the like can be suppressed, and by providing the black processing portion on the inner peripheral surface of the interval member, the inner peripheral surface can be formed. Flare and ghost due to reflection can be prevented. The other actions and effects are the same as those of the first embodiment.
This is the same as the embodiment. The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the invention. [Appendix] According to the above-described embodiment of the present invention as described in detail above, the following configuration can be obtained. (1) A lens frame having a through hole, a tip lens hermetically joined to a concave portion forming the through hole formed at the tip of the lens frame, and the through hole communicating with the concave portion. At least one proximal lens having a diameter configured to be disposed in a hole having a diameter smaller than the diameter of the recess;
Disposed between the proximal lens and the distal lens,
An imaging unit for an endoscope, comprising: a spacing member that forms a space having a predetermined spacing between a base end surface of the tip lens and a bottom surface of the recess. (2) The imaging unit according to attachment 1, wherein an optical stop is integrated with the spacing member. (3) The imaging unit according to Supplementary Note 1 or 2, wherein at least the inner peripheral surface of the spacing member is blackened. (4) A solid-state image pickup device on which a light beam passing through a lens group in a lens frame constituting an observation optical system forms an image, and the solid-state image pickup device is held at one end and the lens is held at the other end. An imaging unit for an endoscope that includes an element frame for holding a frame, and joins the element frame and the lens frame using both bonding and welding connection and fixing means, wherein the lens frame and the element frame include: An imaging unit for an endoscope in which welding joints and bonding joints having different diameters are provided apart from each other. (5) A joint for welding is provided at a large diameter portion of the lens frame and a large hole of the element frame, and a bonding portion for bonding is provided at a small diameter portion of the lens frame and a small hole of the element frame. An imaging unit for an endoscope according to Supplementary Note 4 provided in the unit. (6) A bonding portion for bonding is provided at a large diameter portion of the lens frame and a large diameter hole of the element frame, and a welding portion is formed at a small diameter portion of the lens frame and a small diameter hole of the element frame. An imaging unit for an endoscope according to Supplementary Note 4 provided in the unit. As described above, according to the present invention, the number of parts and the number of assembling steps are not increased in order to secure the resistance to autoclave sterilization, and the light incident from the tip cover glass is not increased. This has the effect of preventing flare and ghost due to reflection on the inner peripheral surface of the through-hole of the lens frame and obtaining a good observation image.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 3 relate to a first embodiment of the present invention, and FIG. 1 illustrates a configuration of an imaging unit of an endoscope. FIG. 2 illustrates a lens frame. FIG. 3 is a diagram illustrating a relationship between a lens frame, a lens, and a spacing member. FIG. 4 is a diagram illustrating another configuration of an imaging unit of an endoscope according to a second embodiment of the present invention. Description: 1 ... Imaging unit 2 ... Objective lens unit 3 ... CCD 4 ... Circuit board 21 ... Lens frame 22 ... Recess 23 ... Front lens 24 ... Hole 26 ... Base lens group 27 ... Spacing member

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Claims (1)

Claims: 1. A lens frame having a concave portion on the distal end side and having a through-hole penetrating a bottom surface portion and a base end side of the concave portion, and covering an inner surface of the concave portion of the lens frame. A plating portion, a tip lens disposed in the concave portion of the lens frame, and a solder portion provided between the distal end lens disposed in the concave portion of the lens frame and a plating portion covering an inner side surface of the concave portion of the lens frame. An anti-reflection section provided on the inner peripheral surface of the through hole of the lens frame, for preventing light incident from the tip lens and passing through the through hole from being reflected on the inner peripheral surface of the through hole. An endoscope apparatus characterized by the above-mentioned.