JP2006262915A - Objective part of endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an objective part of an endoscope, capable of jointing/fixing a lens at the distal end to a lens frame in such a state that the lens is not broken because of the thermal expansion when the lens and lens frame are jointed or when the lens and lens frame are sterilized with high-pressure steam, obtaining excellent optical performance without generating the misalignment between the lens at the distal end and other lenses, and allowing an operator to visually confirm the state of the joint and air-tightness easily and securely without using a special device or without labor for confirming the state of the joint. <P>SOLUTION: The objective part of the endoscope is formed so that the outer diameter of the lens 11 at the distal end is the same as the outer diameter of the distal end part of the lens frame 10. The rear end face of the lens 11 at the distal end is air-tightly fixed to the distal end face of the lens frame 10 by the brazing without forming a peripheral wall facing the outer surface of the lens 11 at the distal end in the distal end part of the lens frame 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an objective part disposed at the distal end of an insertion part of an endoscope.

  The objective part of an endoscope is generally a state-of-the-art lens because of the peculiarity that it is necessary to incorporate a small lens group with a wide viewing angle with a diameter of several millimeters or less into a state having complete airtightness and chemical resistance. A structure is adopted in which all or some of the lenses except the most advanced lens are fitted and fixed from the rear in a lens frame, and are airtightly bonded and fixed to the front end portion of the frame.

In recent years, the durability required to withstand high-pressure steam sterilization has been demanded. Therefore, the outer peripheral surface or the back surface of a state-of-the-art lens is preliminarily plated with gold, and the portion is made of a metal lens. The frame is joined by soldering or the like (for example, Patent Documents 1 and 2).
JP2004-94043 JP 2000-193892 A

  In the invention described in Patent Document 1, as shown in FIG. 12, the outer peripheral surface of the most advanced lens 101 is joined to the inner peripheral surface of the lens frame 100 by soldering or the like. During expansion or contraction that occurs during heating or subsequent high-pressure steam sterilization, the joint A is damaged due to the difference in thermal expansion coefficient between the state-of-the-art lens 101 and the lens frame 100, so-called water leakage failure. May occur.

  On the other hand, in the invention described in Patent Document 2, as shown in FIG. 13, the outer diameter of the state-of-the-art lens 101 is formed small enough to be loose with respect to the inner diameter of the lens frame 100. By joining the back surface of the most advanced lens 101 to the front end surface of the lens frame, damage to the joint A due to thermal expansion does not occur.

  However, there is a case where the center line between the axis of the state-of-the-art lens 101 and the axis of the other lens becomes large, so that the performance as an optical system is greatly deteriorated. Since it is the part A and the joining state cannot be visually observed after the joining operation, there is a disadvantage that the inspection apparatus and the inspection work become large, for example, an X-ray apparatus is required to confirm the joining state.

  Therefore, the present invention can bond and fix the state-of-the-art lens and the lens frame in a state where they are not damaged by thermal expansion or the like during bonding and high-pressure steam sterilization. Good optical performance can be obtained without any misalignment between them, and it is easy and reliable to visually confirm the joining state and the airtight state without any special equipment or labor for confirming the joining state. It is an object of the present invention to provide an endoscope objective section that can be performed in a simple manner.

  In order to achieve the above object, the objective part of the endoscope of the present invention has a state-of-the-art lens of an objective optical system including a plurality of lenses, which is hermetically bonded and fixed to a tip portion of a metal lens frame. In the objective part of an endoscope with a configuration in which all or some of the lenses except for the lens are fitted and fixed from behind in the lens frame, the outer diameter of the most advanced lens is the outer diameter of the tip of the lens frame. In addition to forming the same size as the dimensions, without forming a peripheral wall facing the outer periphery of the most advanced lens at the tip of the lens frame, the rear end surface of the most advanced lens is hermetically sealed by low contact with the tip surface of the lens frame. It is fixed.

  The state-of-the-art lens may be a concave lens, and the portion near the outer edge of the rear end surface may be fixed in an annular shape to the front end surface of the lens frame.

  According to the present invention, the rear end surface of the most advanced lens is airtightly fixed to the front end surface of the lens frame in a low contact manner without forming the peripheral wall facing the outer periphery of the most advanced lens at the distal end portion of the lens frame. Can bond and fix the state-of-the-art lens and lens frame in a state where they are not damaged due to thermal expansion during bonding and high-pressure steam sterilization treatment, and it takes special equipment and labor to check the bonding state. It is possible to easily and surely confirm the joined state and the airtight state without visual inspection, and the outer diameter of the most advanced lens is formed to be the same as the outer diameter of the tip of the lens frame. In addition, misalignment does not occur between the state-of-the-art lens and other lenses, and good optical performance can be obtained.

  The most advanced lens of the objective optical system including multiple lenses is airtightly bonded and fixed to the tip of the metal lens frame, and all or some of the lenses except the most advanced lens are fitted into the lens frame from the rear. In the objective part of the endoscope with a fixed configuration, the outer diameter of the most advanced lens is formed to be the same as the outer diameter of the distal end of the lens frame, and the most advanced lens is formed at the distal end of the lens frame. Without forming a peripheral wall facing the outer periphery of the lens, the rear end surface of the most advanced lens is airtightly fixed to the front end surface of the lens frame by low contact.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 2 is a front view of the distal end of the insertion portion of the endoscope. On the distal end surface of the distal end main body 1 connected to the most distal portion of the insertion portion, there are an observation window 2, an illumination window 3, a treatment instrument protrusion 4 and the like. Has been placed.

  FIG. 3 is a side cross-sectional view of the distal end of the insertion portion, and at the back of the treatment instrument protrusion 4, the distal end portion of the treatment instrument insertion channel 5 that is inserted and disposed throughout the entire length of the insertion section is straight with the treatment instrument protrusion 4. It is connected to the front-end | tip part main body 1 in the state connected to.

  Reference numerals 11 and 12 denote lens groups constituting the objective optical system, and the state-of-the-art lens 11 has its rear end surface fixed to the front end surface of the lens frame 10 (joint portion A) and is loosely fitted into the observation window 2. The adhesive is applied to the fitting surface.

  The rear lens group 12 following the state-of-the-art lens 11 is three lenses in this embodiment, and is fitted into the cylindrical lens frame 10 without being misaligned and fixed thereto. The rear group lens 12 may be a single lens.

  An imaging surface of the solid-state imaging device 13 is disposed at the projection position of the subject by the objective optical systems 11 and 12, and the solid-state imaging device 13 and an electronic component or the like disposed adjacent to the rear thereof are fixed inside. The front end portion of the unit frame 14 is fitted and fixed to the outer peripheral portion of the rear half portion of the lens frame 10. Reference numeral 15 denotes a signal cable inserted through the entire length of the insertion portion.

  FIG. 1 shows an imaging unit of an endoscope configured as described above. The lens frame 10 is made of metal and has an outer diameter that is the same throughout the entire length. It is formed in the cylindrical shape formed smaller than the internal diameter of this part.

  A peripheral wall facing the outer periphery of the most advanced lens 11 is not formed at the distal end portion of the lens frame 10, and the rear end surface of the most advanced lens 11 is joined to the distal end surface of the lens frame 10 coaxially by a low contact. It is fixed. A is a joint portion by the low contact, and the rear lens group 12 is fitted and fixed to the lens frame 10 from the rear.

  The most advanced lens 11 has an outer diameter that is the same as the outer diameter of the lens frame 10. Therefore, when the imaging unit is assembled into the fitting hole of the tip body 1, it can be easily inserted and set from behind. The state-of-the-art lens 11 is a concave lens in this embodiment, but it may be a plane parallel plate or the like or a meniscus lens or the like.

  FIG. 4 shows a jig 50 that is used when the state-of-the-art lens 11 is joined to the lens frame 10 by low contact. The jig 50 has a bottomed bottom on which the state-of-the-art lens 11 and the lens frame 10 are fitted. The receiving hole 51 is formed.

  The diameter of the receiving hole 51 is such that both the state-of-the-art lens 11 and the lens frame 10 can be fitted without backlash (for example, the diameter of the state-of-the-art lens 11 and the lens frame 10 formed to the same dimension plus 0.01 to The depth is formed such that the most advanced lens 11 and lens frame 10 are completely hidden.

  The jig 50 is formed of a material that can withstand the heating temperature at the time of low contact, such as carbon, and that is not joined by low contact. 52 is a soldering material made of a material such as gold tin (Au—Sn), for example, and is formed in a thin annular shape (doughnut shape) that matches the shape of the joint A.

  When the state-of-the-art lens 11 is brought into low contact with the lens frame 10 using such a jig 50, first, as shown in FIG. 5, the state-of-the-art lens 11 is received by the jig 50 from the front end surface side. Fit into the bottom of the hole 51 and set.

  Next, as shown in FIG. 6, the low contact material 52 and the lens frame 10 are dropped into the receiving hole 51 in order. Accordingly, as shown in FIG. 7, the lens frame 10 and the most advanced lens 11 are set on the coaxial line in the receiving hole 51 with the low contact material 52 sandwiched therebetween and without misalignment. .

  Therefore, as shown in FIG. 8, a load pin 90 or the like is placed on the lens frame 10, or in that state, the whole is repeatedly pulled up and down 180 °, and placed in a furnace having a temperature of 450 ° C. or higher, for example. Put it in for a predetermined time.

  Then, the soldering material 52 is melted, and the lens frame 10 and the state-of-the-art lens 11 are both heated to about the temperature in the furnace, so that the surface thereof is in a so-called wet state with respect to the soldering material 52. Thus, a portion near the outer edge of the rear end surface (back surface) of the most advanced lens 11 is bonded and fixed to the front end surface of the lens frame 10 in an annular and airtight manner by low contact.

  In this way, the lens frame 10 and the state-of-the-art lens 11 are fixed to each other by a low contact with almost no misalignment, and a peripheral wall facing the outer periphery of the state-of-the-art lens 11 is formed on the lens frame 10. Since it is not formed, the joint A will not be damaged by expansion and contraction caused by temperature changes such as during low-pressure contact or subsequent high-pressure steam sterilization.

  And, as shown in FIG. 9, it is possible to easily and surely confirm the joining state and the airtight state of the joining portion A by low contact, so that special equipment and labor are required for the inspection of the joining portion A. The quality of the joint A can be ensured without spending.

  Next, as shown in FIG. 10, the rear lens group 12 is dropped into a lens frame 10 having the most advanced lens 11 bonded to the tip and fixed by adhesion or caulking. As shown in FIG. An imaging unit as shown in FIG. 1 is completed by fitting the tip of the frame 14 to the latter half of the lens frame 10 and fixing it by bonding or caulking.

It is side surface sectional drawing of the imaging unit of the Example of this invention. It is a front view of the insertion part front-end | tip of the endoscope of the Example of this invention. It is side surface sectional drawing of the insertion part front-end | tip of the endoscope of the Example of this invention. It is a disassembled perspective view of the brazing jig of the Example of this invention. It is a schematic sectional drawing which shows the brazing process of the Example of this invention in order. It is a schematic sectional drawing which shows the brazing process of the Example of this invention in order. It is a schematic sectional drawing which shows the brazing process of the Example of this invention in order. It is a schematic sectional drawing which shows the brazing process of the Example of this invention in order. It is a schematic sectional drawing which shows the state which looks at the state of the low contact of the Example of this invention. FIG. 4 is a schematic cross-sectional view sequentially illustrating an imaging unit assembling process after row contact according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view sequentially illustrating an imaging unit assembling process after row contact according to an embodiment of the present invention. It is side surface sectional drawing of the 1st example in the state in which the objective optical system of the conventional endoscope was integrated in the lens frame. It is side surface sectional drawing of the 2nd example in the state in which the objective optical system of the conventional endoscope was integrated in the lens frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lens frame 11 State-of-the-art lens 12 Rear group lens 50 Jig 51 Receiving hole 52 Low contact material A Joint part

Claims (2)

The most advanced lens of the objective optical system including a plurality of lenses is hermetically bonded and fixed to the tip portion of the metal lens frame, and all or some of the lenses except the most advanced lens are inserted into the lens frame from behind. In the objective part of the endoscope that is configured to be fitted and fixed,
The outer diameter dimension of the state-of-the-art lens is formed to be the same as the outer diameter dimension of the tip portion of the lens frame, and the peripheral wall facing the outer periphery of the state-of-the-art lens is not formed at the tip portion of the lens frame. In addition, the objective part of the endoscope is characterized in that the rear end surface of the most advanced lens is airtightly fixed to the front end surface of the lens frame by low contact.   The objective part of the endoscope according to claim 1, wherein the state-of-the-art lens is a concave lens, and a portion of the rear end surface near the outer edge is fixed to the front end surface of the lens frame in an annular shape.

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