JPH10160992A - Lens fixing structure for endoscope and lens fixing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the inter-lens distance of a combined lens with high accuracy by providing a holder with plural pieces of projectors solidified after melting by laser shots on its inner peripheral surface in such a manner that these projectors solidified after melting constitute a spacer part to regulate the prescribed gap between a front lens part and a rear lens part. SOLUTION: The lens L consists of the two-element combined lens consisting of the front lens part 1 and the rear lens part 2. Both lens parts 1, 2 are inserted and held apart the prescribed gap G into a short cylindrical metallic holder 3. There is a slight gap between the font end face 4a of an image guide 4 and the rear end face 2a of the rear lens part 2 without the intervention of a binder, such as adhesive, therebetween. A connecting cylindrical body 5 is inserted onto the front end of the image guide 4 and the holder 3. The holder 3 has four pieces of the projectors 6 solidified after melting formed by the laser shots on its inner peripheral surface. The spacer part 7 regulating the prescribed gap G between the front lens part 1 and the rear lens part 2 is constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a lens fixing structure of an observation optical system (on the distal end side) of an endoscope, and a method of fixing the lens.

[0002]

2. Description of the Related Art When a two-lens combination lens is used as the lens of the above-mentioned observation optical system, as shown in FIG.
A spacer c is interposed between the lens and the rear lens b to regulate a predetermined gap G, and a short cylindrical holder e (shown by a two-dot chain line in FIG. 5) is externally fitted and fixed. , Has been used in the past.

[0003]

In recent years, endoscopes inserted into the body have been increasingly reduced in diameter, for example, to alleviate the pain of patients. The combination lens as shown in FIG. 5 has an extremely small outer diameter D of 0.6 mm or less.

Accordingly, the dimension of the short cylindrical spacer c is extremely small. For example, the outer diameter, thickness,
The width must be 0.6 mm, 0.05 mm, and 0.18 mm, and the dimensional tolerances are strictly required. Therefore, there is a problem that it is very difficult to manufacture such an extra-fine spacer c and the yield is poor.

Accordingly, the present invention, as shown in FIG. 6 (b), has a structure in which the spacer portion f is integrated with the holder e.
investigated. That is, a manufacturing method of cutting the inner peripheral surface of the hole of the pipe material g and forming the spacer portion f in an inner flange shape as shown in FIG. Is difficult (because it is a very small part).

It is an object of the present invention that such an outer diameter D is 0.6 m.
Improve the holder used for ultra-thin lens outer diameters of less than m to provide an endoscope lens fixing structure that can be manufactured with high precision and ease, and provide high yield, high efficiency, and high precision spacers. Provision of a lens fixing method capable of manufacturing a part to accurately obtain a lens distance of a combined lens,
It is in.

[0007]

Therefore, an endoscope lens fixing structure according to the present invention comprises a short cylindrical metal holder into which a front lens portion and a rear lens portion are inserted and held with a predetermined gap, and The holder has a plurality of melt-solidified protrusions on the inner peripheral surface by laser shot, and the melt-solidified protrusions constitute a spacer portion that regulates the predetermined gap between the front lens portion and the rear lens portion. .

In the method of fixing a lens according to the present invention, a short cylindrical metal pipe material is provided with a laser shot of such a degree that it is melted instantaneously without penetrating from the outer peripheral side thereof, and solidified by cooling to the inner peripheral side. A molten solidified projection is formed, and the front lens unit and the rear lens unit are inserted from both openings until the rear end of the front lens unit and the front end of the rear lens unit abut on the molten solidified projection. The front lens unit and the rear lens unit are held and fixed while restricting a predetermined gap between the front lens unit and the rear lens unit using the solidified projection as a spacer unit.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on the illustrated embodiments of the present invention.

FIG. 1 is an enlarged cross-sectional view of the end of the endoscope (the objective lens and its vicinity).
And a rear lens unit 2. The two lens units 1 and 2 are inserted and held in a short cylindrical metal holder 3 with a predetermined gap G (for adjusting the distance between the lenses), and an image guide 4. There is a slight gap between the front end surface 4a of the rear lens unit 2 and the rear end surface 2a of the rear lens unit 2 without interposing a fixed substance such as an adhesive. 5 is externally fitted.

The holder 3 is made of a metal such as stainless steel, and when the outer diameters of the front lens unit 1 and the rear lens unit 2 according to the present invention are D, 0.2 mm ≦ D ≦ 0.6 mm. As described above, since the diameter is extremely small, the inner diameter of the holder 3 is basically about 0.2 mm to 0.6 mm.

FIG. 2 is an enlarged vertical sectional view of FIG.
In the cross-sectional view of FIG.
Has four melt-solidified protrusions 6 formed on the inner peripheral surface by laser shot (irradiation), and the protrusions 6 have the same shape.
Thereby, as shown in FIG. 1, a spacer portion 7 that regulates a predetermined gap G between the front lens portion 1 and the rear lens portion 2 is configured.

The number of the protruding members 6 may be three or more, and is not limited to the above four, and can be freely increased or decreased. As can be seen from FIGS. 1 and 2, the base of the protruding element 6 is engaged with the rear corner of the front lens 1 and the front corner of the rear lens 2 (to regulate the predetermined gap G). Stop. Therefore,
The accuracy of the dimension W in FIG. 2 is important, but since the protrusion 6 is formed by melting and solidifying by laser shot, the accuracy can be sufficiently ensured.

Next, a method of manufacturing the holder 3 integrally including the spacer portions 7 and a method of fixing the front and rear lens portions 1 and 2 will be described in further detail. FIG. 4A shows a short cylindrical metal pipe material 8, for example,
A stainless steel pipe with an outer diameter of 0.7 mm, an inner diameter of 0.6 mm, and a thickness of 0.05 mm is cut into short lengths. An Nd-YAG laser 9 is applied to the pipe material 8 from the outer peripheral surface side thereof in a direction perpendicular to (in a vertical downward direction) such that the wall of the pipe material 8 is melted instantaneously without penetrating the wall of the pipe material 8. Or short) laser shot (irradiation).

The conditions for the laser shot are that the laser irradiation time during normal cutting is sufficiently shorter than 2 msec (for example, 1 msec) and that N ₂ (instead of O ₂ gas at 0.5 atm for cutting) is used. The gas is blown at low pressure (eg, about 0.3 atm). Thus, the protrusion 6 can be formed (melted and solidified) on the inner peripheral surface of the pipe blank 8 without penetrating only by the shock wave and the ablation effect of the laser. Thereby, the protrusion 6
Width W and height are (0.20 ± 0.02) mm,
(0.05 ± 0.01) mm and a highly accurate one can be easily obtained.

As shown in FIG. 4C, the pipe blank 8
Are intermittently rotated to form the protruding members 6... One after another by the above-mentioned laser shot on the same cutting line with equal circumferential distribution.

In this manner, the holder 3 as shown in FIG. 2 is manufactured. Thereafter, the front lens unit 1 is brought into contact with the protrusion 6 (spacer unit 7) through one opening of the holder 3 (locking). ) And insert the rear lens portion 2 from the other opening of the holder 3 into the protrusion 6 (spacer portion 7).
The lens portions 1 and 2 are held and fixed with an adhesive or the like while regulating a predetermined gap G between the lens portions 1 and 2.

In this way, the two lens units 1 and 2 can be easily fixed so that a highly accurate lens distance can be obtained. In particular, the outer diameter D of both lens portions 1 and 2 is 0.2 mm to 0.6 m
The spacer portion 7 having an extremely small diameter of m can be manufactured with high precision, and the lens portions 1 and 2 can be fixed and held reliably and easily.

[0019]

According to the present invention, the following significant effects can be obtained by the above configuration.

According to claim 1, the lens diameter is 0.6 mm.
The gap G between the front lens portion 1 and the rear lens portion 2 of the ultra-thin combined lens L as described below can be obtained with high accuracy and certainty. Since the spacer portion 7 is formed integrally with the holder 3, the assembling operation is also facilitated, and the loss or damage of the spacer during the operation can be prevented, so that the operation efficiency can be improved. (According to claim 2) A spacer portion 7 having a high-precision dimension is provided on the holder 3 for the ultra-fine lens L (as described above).
It can be integrally formed, and the practical effect is remarkable. Then, the distance between the front and rear lens portions 1 and 2 inserted into the holder 3 is regulated with high precision, and the performance as a lens is stably excellent.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a holder.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is an explanatory view of a manufacturing method.

FIG. 5 is an explanatory diagram of a conventional example.

FIG. 6 is an explanatory sectional view of a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front lens part 2 Rear lens part 3 Holder 6 Projector 7 Spacer part 8 Pipe material 9 Laser G Gap D Outer diameter

Claims (2)

[Claims] 1. A short cylindrical metal holder into which a front lens portion and a rear lens portion are inserted and held with a predetermined gap, and the holder includes a plurality of molten and solidified projections formed by laser shot on an inner peripheral surface. An endoscope lens fixing structure, characterized in that the melt-solidified protrusion constitutes a spacer section for regulating the predetermined gap between the front lens section and the rear lens section. 2. A short cylindrical metal pipe material is subjected to a laser shot of such a degree that it is melted instantaneously without penetrating from the outer peripheral surface side thereof, and a molten and solidified projection is formed on the inner peripheral surface side by cooling and solidification, Insert the front lens portion and the rear lens portion from both openings until the rear end portion of the front lens portion and the front end portion of the rear lens portion abut on the fusion solidified projection, and use the fusion solidified projection as a spacer portion. A method of fixing a lens for an endoscope, comprising: holding and fixing a front lens unit and a rear lens unit while regulating a predetermined gap between a front lens unit and a rear lens unit.