JPH05113542A - Objective optical system of endoscope - Google Patents

Abstract

PURPOSE:To provide the objective optical system of the endoscope which facilitates working, is high in assembly accuracy, can enhance the strength of adhesion of lenses to a frame member without hindering an optical observation function and water tightness and can effectively prevent the fogging of a visual field. CONSTITUTION:The frame member 41 and a light shielding member 43 are joined by an adhesive 47 by fitting this light shielding member 43 into a detaining part 41a of the frame member 41. The frame member 41 and the 1st lens 42 are surely and water-tightly joined by admitting the adhesive 47 down to a 1st adhesive pool 45 from the spacing between this frame member 41 and the 1st lens 42. Further, the frame member 41 and the 2nd lens 44 are surely and water-tightly joined by admitting the adhesive 47 down to a 2nd adhesive pool 46 from the spacing between the frame member 41 and the 2nd lens 44. The 1st adhesive pool 45 and the 2nd adhesive pool 46 are formed in the axial direction of the lenses 42, 44 and, therefore, the working is easy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective optical system for an endoscope used for endoscopic observation.

[0002]

2. Description of the Related Art An endoscope is widely used in the medical field for observing the inside of a body cavity and the like, and by using a treatment tool if necessary, a medical treatment can be performed. In the industrial field, endoscopes are widely used for inspecting the inside of jet engines or the inside of plants.

By the way, in the objective optical system of an endoscope,
As for the joining technique, many techniques have been conventionally shown.

For example, in Japanese Utility Model Laid-Open No. 62-96616, as shown in FIG. 5, a cylindrical frame member 2 having a step is formed.
On the other hand, there is shown an objective optical system 1 for an endoscope which is configured by sequentially arranging at least a first lens 3, a light blocking member 4, and a second lens 5 from the tip side. In the objective optical system 1 of the endoscope, the first lens 3 and the light blocking member 4 have the same diameter, and the frame member 2 is joined to the light blocking member 4 and the light blocking member 4 from the front end side of the frame member 2. This is done by pouring the adhesive 6 through the gap between the frame member 2 and the first lens 3 in a state where the first lens 3 is dropped in and brought into close contact with each other. Here, the light shielding member 4 also serves to keep the distance between the first lens 3 and the second lens 5 constant. Further, an adhesive pool 7 is provided in a portion of the light shielding member 4 that comes into contact with the first lens 3 to prevent the adhesive 6 from flowing out to the lens surface when the first lens 3 is attached. In addition, the adhesive area is increased to increase the adhesive strength.

However, in the configuration of the objective optical system 1 of the endoscope, since the processing of the light shielding member 4 is complicated, the precision is varied, and the optical observation function such as flare caused by reflected light is affected. Not only that, but since the squeezing requires a certain thickness, the surface distance between the first lens 3 and the second lens 5 cannot be reduced so much that the angle of view is limited. New functional challenges were emerging.

In order to overcome the above-mentioned problems in the observation function, in Japanese Patent Laid-Open No. 63-108314, as shown in FIG. 6, a frame member 9 having a space holding portion 8 which also functions as a space plate. On the other hand, there is shown the objective optical system 10 of the endoscope in which the light blocking member 11 is dropped from the tip side and sandwiched and joined by the first lens 3 and the interval holding section 8.

However, the objective optical system 1 of the endoscope is
In No. 0, since the light-shielding member 11 was thin, it was not possible to form the adhesive pool on the light-shielding member 11 as in the prior art. Therefore, due to a decrease in the adhesive strength of the first lens 3 to the frame member 9 and a decrease in the watertightness, external moisture penetrates into the gap between the first lens 3 and the second lens 5, and Due to the change, a problem that a so-called visual field haze occurs, which is a phenomenon that the visual field is obstructed by the deposition of fine water droplets on the inner surface of the first lens 3, has occurred.

[0008]

As described above, in the prior art, when it is attempted to increase the adhesive strength and watertightness of the first lens to the frame member, complicated processing is required, which causes variation in accuracy. In addition to affecting the optical observation function such as the occurrence of flare due to reflected light, there are problems with the observation function such as the angle of view being limited. The adhesion strength and watertightness of the first lens are deteriorated, which causes a problem such as clouding of the visual field.

As a technique for solving these problems of the prior art, as shown in FIG. 7, a technique of using a frame member 13 having an adhesive pool 12 formed in the radial direction of the first lens 3, and as shown in FIG. Another possible technique is to use the frame member 15 in which the adhesive pool 14 is formed in the axial direction of the first lens 3.

However, as shown in FIG. 7, in order to form the adhesive pool 12 in the radial direction of the first lens 3 in the frame member 13 for storing the objective optical system of the endoscope, which has an extremely small diameter, In addition to requiring special cutting tools and equipment, processing is extremely difficult. In addition, positioning of the light shielding member 11 is difficult, which causes problems such as variations in accuracy.

Further, as shown in FIG. 8, even when the adhesive reservoir 14 is formed on the frame member 15 in the axial direction of the first lens 3, the inner diameter of the frame member 15 and the outer diameter of the light shielding member 11 are as follows. Since the diameters are almost the same, the adhesive 6 can flow into the adhesive reservoir 14 up to the adhesive reservoir table 14a on the first lens 3 side, but is partitioned and formed by the light shielding member 11 on the opposite side of the adhesive reservoir table 14a. Adhesive pool back 14b
Since the adhesive 6 cannot flow into the above, the adhesive strength and the watertightness of the first lens 3 to the frame member 15 are deteriorated, and the problem that the visual field becomes cloudy occurs.

The present invention has been made in view of the above circumstances. It is easy to process, has high assembly accuracy, and improves the adhesive strength and watertightness of a lens to a frame member without supporting the optical observation function. It is an object of the present invention to provide an objective optical system of an endoscope which can be effectively prevented from being obscured by a visual field.

[0013]

In order to achieve the above object, an objective optical system for an endoscope according to the present invention comprises a first lens, a light blocking member, and a second lens in a frame member from the front end side. Alternatively, in an objective optical system of an endoscope in which a filter and a filter are sequentially arranged, a light-shielding member is formed to have a smaller diameter than that of the first lens, and the light-shielding member is abutted on the first lens without contacting the first lens. It is bonded to the inside of the frame member, and an adhesive pool for bonding the first lens is formed inside the frame member.

[0014]

[Operation] In the above configuration, in order to assemble the objective optical system of the endoscope, first, from the tip side of the frame member, a light blocking member formed to have a diameter smaller than that of the first lens is placed in the frame member. , And the light shielding member and the frame member are bonded with an adhesive.

Next, the first lens is inserted into the frame member from the tip side of the frame member. At this time, the light shielding member does not come into contact with the first lens.

Then, an adhesive is poured from the front end side into a gap between the first lens and the frame member, and the adhesive is caused to flow into an adhesive pool formed in the frame member, whereby the first lens Is securely and watertightly joined to the frame member.

Next, after inserting the second lens or filter into the frame member from the opposite side of the frame member to the side where the first lens and the light shielding member are joined,
An adhesive is poured in to securely bond the second lens or filter into the frame member.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIGS. 1 to 3 show a first embodiment of the present invention, FIG. 1 is a structural explanatory view of an objective optical system of an endoscope, and FIG. 2 is an explanatory view of the entire endoscope. 3 is an enlarged view of part A in FIG.

In FIG. 2, reference numeral 21 designates an endoscope, which has an observing means built therein and an elongated and flexible insertion portion 22 which can be inserted into a body cavity or the like.
It is formed at the rear end of the operation portion 23 and a wide operation portion 23 which is continuously provided at the rear end of the insertion portion 22 and in which the air / water / suction switching button 26, the bending knob 31 and the like are arranged. It consists of an eyepiece section 24 and a light guide cable 25 extending from the side of the operation section 23. The end of the light guide cable 25 is attached to and detached from a light source device (not shown) through a connector (not shown). Connected freely.

The insertion portion 22 has a hard tip portion 27, a bendable bending portion 28, and a flexible flexible tube portion 2 from the tip end side.
9, the bending portion 28 can be bent by operating the bending knob 31 provided on the operation portion 23.

Further, the endoscope 21 is provided with a channel (not shown) through which a treatment tool or the like can be inserted to perform a medical treatment or the like, and the channel is an insertion port of the operation portion 23. From 37, through the inside of the insertion portion 22 to the opening 38 at the end of the tip portion 27. This channel is formed of a flexible tube inside the insertion portion 22, and the tip of this tube is fixed to a base (not shown) fixed to the through hole of the tip portion 27.

Further, by connecting the connector of the light guide cable 25 to the light source device, the white light of the lamp (not shown) in the light source device is irradiated to the end face of the light guide (not shown) and transmitted by this light guide. The illumination light is emitted forward from the illumination window 32 to which the end face on the side of the tip portion 27 is attached, so that the subject (not shown) can be illuminated.

An optical image of the subject illuminated by the illumination light is formed on one end face of an image guide (not shown) fixed to the focal plane thereof by the objective optical system 40 provided at the tip 27. An optical image is transmitted to the other end surface on the eyepiece 24 side by this image guide. An eyepiece lens (not shown) is arranged so as to face the other end face, and magnified observation is possible with the naked eye through the eyepiece lens.

As shown in FIGS. 1 and 3, the objective optical system 40 includes a cylindrical frame member 41 in which a first lens 42 and an outer diameter of the first lens 42 are arranged from the front end side. And the second lens 4 and the light-shielding member 43 having a smaller outer diameter.
4 is a hooking portion 4 formed in the middle of the frame member 41.
1a are sequentially arranged.

That is, the hooking portion 41a of the frame member 41
The front end side is formed in a two-step shape, and as a result, the front end side of the frame member 41 can hold the first lens 42 and the inner diameter a that can store the first lens 42. And,
An inner diameter c that can store the light shielding member 43 and is the same as the outer diameter of the light shielding member 43, and an inner diameter b that can lock the light shielding member 43 are formed in a>c> b. Also,
The second lens 44 can be hooked on the rear end side of the hooking portion 41a of the frame member 41.

Further, at a portion of the hooking portion 41a of the frame member 41 where the first lens 42 and the second lens 44 are hooked, the first lens 42 and the second lens 44 are axially moved to the first lens 42 and the second lens 44, respectively. A first adhesive pool 45 for one lens 42 and a second adhesive pool 46 for the second lens 44 are formed.

The frame member 41 and the light shielding member 43 are
The light shielding member 43 is fitted into the hooking portion 41a and joined by an adhesive 47. Further, the frame member 41 and the first lens 42 are the frame member 41 and the first lens 42.
The adhesive 47 flows into the first adhesive pool 45 from the gap between the frame member 41 and the second lens 44, and the frame member 41 and the second lens 44 are separated from each other by the gap between the frame member 41 and the second lens 44. The adhesive 47 flows into the second adhesive pool 46 and is bonded.

By constructing the objective optical system 40 in this way, the frame member 41, the light blocking member 43, and the first lens 4 are provided.
The second and second lenses 44 can be cemented independently of each other.

Therefore, when the frame member 41 is bonded to the first lens 42 and the second lens 44, the adhesive 47 can flow into the first adhesive pool 45 and the second adhesive pool 46 to bond them together. Therefore, it is possible to keep the adhesive agent 47 around smoothly, increase the adhesion area, and reduce the adhesion unevenness, so that the watertightness and the adhesion strength can be sufficiently ensured.

Further, since the first adhesive pool 45 and the second adhesive pool 46 can be processed in the axial direction of the first lens 42 and the second lens 44, the frame member 41 may have a simple shape. It is also possible to improve the workability and suppress variations in processing accuracy.

Further, since the light shielding member 43 may have a simple shape, it is possible to improve the workability and suppress the variation in the processing accuracy, and it is possible to reduce the wall thickness.

Further, the frame member 41 and the light shielding member 43 can be joined by fitting them into the hooking portion 41a of the frame member 41, and particularly, the work such as positioning is not required and can be easily performed. The light shielding member 43 can be joined reliably and accurately.

[Second Embodiment] FIG. 4 is a structural explanatory view of an objective optical system of an endoscope according to a second embodiment of the present invention.

In this second embodiment, the surface of the second lens on the front end side is a flat surface, and as a result, the front end side of the second lens is formed without stepping the hooking portion of the frame member. It differs from the first embodiment in that the light shielding member is joined to the frame member by utilizing the flat surface.

That is, as shown in FIG. 4, the objective optical system 50 includes a first lens 42 and a diameter smaller than the outer diameter of the first lens 42 in the cylindrical frame member 51 from the front end side. A light-shielding member 53 having an outer diameter formed therein and a second lens 54 having a flat surface on the front end side are sequentially arranged on a hooking portion 51a formed in the middle of the frame member 51. It is configured.

At the portion of the hooking portion 51a of the frame member 51 where the first lens 42 and the second lens 54 are hooked, the first lens 42 and the second lens 54 are axially attached to the first lens 42 and the second lens 54, respectively. A first adhesive pool 45 for the lens 42 and a second adhesive pool 46 for the second lens 54 are formed.

The frame member 51 and the light shielding member 53 are
The light shielding member 53 is fitted into the hooking portion 51a and brought into contact with the tip side flat surface portion of the second lens 54, and the adhesive 4
7 and the frame member 51 and the first lens 42 are joined together by injecting an adhesive 47 from the gap between the frame member 51 and the first lens 42 to the first adhesive pool 45. Further, the frame member 51 and the second lens 54 are joined by injecting an adhesive agent 47 from the gap between the frame member 51 and the second lens 54 to the second adhesive reservoir 46. ..

By constructing the objective optical system 50 in this way, the frame member 51, the light blocking member 53, and the first lens 4 are provided.
The second lens 54 and the second lens 54 can be cemented independently of each other.

According to this second embodiment, the second lens 5
4 is used to connect the light blocking member 53 to the frame member 51.
Since it can be joined to the hook member 51a of the frame member 51
Since it is not necessary to form the frame member in two steps, the frame member 51 can be processed more easily.

The rest of the configuration, functions and effects are the same as in the first embodiment, so a description thereof will be omitted.

Even if the second lens in the first and second embodiments is a filter, the same effect can be obtained.

Furthermore, if a non-hygroscopic resin such as an epoxy resin is used as the adhesive, it is possible to more reliably prevent the intrusion of moisture from the outside.

Further, in order to improve the assembling accuracy of the light shielding member, it is useful to allow the turning blade to escape from the frame member, but this may be used as an adhesive pool. For this reason, it is not necessary to perform post-processing for providing the adhesive pool.

Further, the shape of the second lens is not limited to the convex lens in the above-mentioned first embodiment or the one having a flat surface portion on the tip side in the above-mentioned second embodiment, and may have any shape (for example, a flat plate). Filter).

[0046]

As described above, according to the present invention, the first lens, the light blocking member, and the
In an endoscope objective optical system in which a second lens or a filter is sequentially arranged, a light shielding member is formed to have a smaller diameter than that of the first lens, and the light shielding member is applied to the first lens. While joining in the frame member without contacting,
Since the adhesive pool for joining the first lens is formed in this frame member, it is easy to process, the assembly accuracy is high, and the adhesion strength and watertightness of the lens to the frame member are not impaired without supporting the optical observation function. Can increase
It is possible to effectively prevent visual field haze.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of an objective optical system of an endoscope according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of the entire endoscope according to the first embodiment of the present invention.

FIG. 3 is an enlarged view of part A of FIG.

FIG. 4 is a structural explanatory view of an objective optical system of an endoscope according to a second embodiment of the present invention.

FIG. 5 is a structural explanatory view of an objective optical system of an endoscope according to a conventional technique.

FIG. 6 is a structural explanatory view of an objective optical system of an endoscope different from that of FIG. 5 according to a conventional technique.

FIG. 7 is an explanatory diagram of a technique in which an adhesive pool is formed in the first lens radial direction on the frame member of FIG.

FIG. 8 is an explanatory diagram of a technique in which an adhesive pool is formed on the frame member of FIG. 6 in the first lens axis direction.

[Explanation of symbols]

 21 Endoscope 40 Objective Optical System 41 Frame Member 41a Locking Part 42 First Lens 43 Light-shielding Member 44 Second Lens 45 First Adhesive Pool 46 Second Adhesive Pool

Claims (1)

[Claims] 1. An objective optical system for an endoscope in which a first lens, a light shielding member, and a second lens or a filter are sequentially arranged in the frame member from the front end side, wherein the first lens In comparison with the above, the light-shielding member is formed to have a smaller diameter, and the light-shielding member is joined in the frame member without contacting the first lens, and the first lens is joined in the frame member. An objective optical system for an endoscope, which is characterized in that an adhesive pool is formed.