JP2006259054A - Objective part of endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an objective part of an endoscope by which a lens at a tip most and a lens frame are joined and fixed to such a state that they are not damaged by thermal expansion in joining and steam sterilization processing under high pressure, etc. and a joined state and an airtight state are simply and surely confirmed by visual inspection without using a special device and taking a trouble for confirmation of the joined state. <P>SOLUTION: A rear end surface of the lens 11 at a tip most is airtightly adhered on the tip surface of the lens frame 10 by brazing without forming a surrounding wall facing the periphery of the lens 11 at a tip most on the tip part of the lens frame 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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, since the back surface of the state-of-the-art lens 101 is the joining portion A and the joining state cannot be visually observed after the joining operation, an inspection apparatus and an inspection work are large, such as an X-ray device being necessary to confirm the joining state. There is an inconvenience.

  Therefore, the present invention is capable of joining and fixing the state-of-the-art lens and the lens frame in a state where they are not damaged due to thermal expansion or the like during joining and high-pressure steam sterilization, and a special device or An object of the present invention is to provide an objective part of an endoscope that can easily and surely confirm a joined state and an airtight state by visual inspection without taking time and effort.

  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 the endoscope having a configuration in which all or some of the lenses except for the lens are fitted and fixed from behind in the lens frame, a peripheral wall facing the outer periphery of the most advanced lens is formed at the tip of the lens frame. Without being formed, the rear end surface of the most advanced lens is airtightly fixed to the front end surface of the lens frame by low contact.

  It should be noted that the outer diameter of the state-of-the-art lens should be formed so as not to exceed the outer diameter of the lens frame. The state-of-the-art lens is a concave lens and the portion near the outer edge of the rear end surface is the tip of the lens frame. The surface may be fixed in an annular shape.

  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 by low contact 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 the lens frame in a state where they are not damaged by thermal expansion or the like during bonding and high-pressure steam sterilization, 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 visually without any problems.

  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 rear end surface of the most advanced lens is used as the distal end surface of the lens frame without forming a peripheral wall facing the outer periphery of the most advanced lens at the distal end portion of the lens frame. Adhering tightly 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 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, in which a lens frame 10 is made of metal, and a cylinder in which the inner diameter of the most distal part is smaller than the inner diameter of the rear part. It is formed in a shape.

  The front end portion of the lens frame 10 is not formed with a peripheral wall facing the outer periphery of the state-of-the-art lens 11, and the rear end surface of the state-of-the-art lens 11 formed with an outer diameter smaller than the outer diameter of the lens frame 10 is The lens frame 10 is hermetically bonded and fixed to the front end surface of the lens frame 10 by low contact. A is the joint by the low contact. The rear group lens 12 is fitted and fixed to the lens frame 10 from behind.

  The state-of-the-art lens 11 is formed so that the outer diameter does not exceed 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 is an exploded view of jigs 50 and 60 used when the state-of-the-art lens 11 is joined to the lens frame 10 by low contact, and the state-of-the-art lens 11 is fitted into the lens receiving jig 50. A bottomed lens receiving hole 51 is formed, and a lens frame receiving hole 61 into which the lens frame 10 is inserted is formed through the lens frame receiving jig 60.

  Then, the lens receiving hole 51 and the lens are received by penetrating the positioning pins 70 through a plurality of (for example, four) positioning holes 52 and 62 formed in alignment with the lens receiving jig 50 and the lens frame receiving jig 60. The lens receiving jig 50 and the lens frame receiving jig 60 are brought into contact with each other in a state in which the axis line with the frame receiving hole 61 coincides.

  Each of the jigs 50 and 60 is formed of a material that can withstand the heating temperature at the time of low contact and is not joined by low contact, such as carbon. 80 is a low contact 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 jigs 50 and 60, first, as shown in FIG. It is set by being fitted into the 50 lens receiving holes 51.

  The diameter of the lens receiving hole 51 is formed so that the most advanced lens 11 can be fitted without looseness (for example, the diameter of the most advanced lens 11 plus about 0.01 to 0.05 mm), and the depth is the most advanced. The back surface side of the lens 11 is formed so as to slightly protrude from the surface of the lens receiving jig 50.

  Next, as shown in FIG. 6, the lens frame receiving jig 60 is superimposed on the lens receiving jig 50 from above. Since the positional relationship between the lens receiving jig 50 and the lens frame receiving jig 60 is regulated by the positioning pins 70, the lens receiving hole 51 and the lens frame receiving hole 61 are set to coincide with each other.

  Therefore, as shown in FIG. 7, the low contact material 80 and the lens frame 10 are dropped into the lens frame receiving hole 61 in order. The diameter of the lens frame receiving hole 61 is formed so that the lens frame 10 can be fitted without looseness (for example, the diameter of the lens frame 10 plus about 0.01 to 0.05 mm).

  Then, as shown in FIG. 8, a load pin 90 or the like is placed on the lens frame 10 so that the low contact material 80 is securely sandwiched between the lens frame 10 and the most advanced lens 11. Alternatively, in this state, the whole is repeatedly turned 180 ° up and down and placed in a furnace having a temperature of 450 ° C. or higher for a predetermined time.

  Then, the soldering material 80 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 80. 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.

  The lens frame 10 and the state-of-the-art lens 11 that are in contact with each other in this manner are hardly misaligned, and a peripheral wall that faces the outer periphery of the state-of-the-art lens 11 is formed on the lens frame 10. Therefore, the joint A does not break due to expansion and contraction that occurs due to 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 image pickup unit as shown in FIG. 1 is completed by fitting the front end portion of the frame 14 to the latter half portion 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 Lens receiving jig 51 Lens receiving hole 60 Lens frame receiving jig 61 Lens frame receiving hole 70 Positioning pin 80 Low contact material A Joint part

Claims (3)

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 rear end surface of the state-of-the-art lens is airtightly fixed to the front end surface of the lens frame by low contact without forming a peripheral wall facing the outer periphery of the state-of-the-art lens at the front end portion of the lens frame. The objective part of the endoscope.   The objective part of the endoscope according to claim 1, wherein an outer diameter of the most advanced lens is formed so as not to exceed an outer diameter of the lens frame.   The objective part of the endoscope according to claim 1 or 2, 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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