JP2000221375A - Observation lens mechanism for optical fiber fusion splicing connection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an observation lens mechanism which eliminates the need for focus adjustment in a fusion splicing connecting machine assembling process, produces no polishing waste, and can be assembled in a fusion splicing connecting machine with high precision. SOLUTION: The observation lens mechanism 10 has an opening part 19 for lens insertion in front of a lens barrel 11. A lens group 13, spacer rings 14, a protection glass 16, etc., are inserted into the lens barrel 11 from the front opening part 19 for lens insertion and a screwing member 15 for positioning is screwed in and fixed to a female screw part 11a formed at a front part on the lens barrel internal surface. A screwing member 15 for positioning which has proper thickness H is selected to obtain an observation lens mechanism which can actualize a highly precise focusing. The need for focus adjustment in the fusion splicing connecting machine assembling process is eliminated to reduce manpower. The front end surface of the lens barrel need not be polished and the problem of the production of waste is not generated. The opening part for lens insertion is situated on the front side of the lens barrel, then the assembly is easy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for observing a fusion spliced portion at the time of optical fiber fusion splicing. The present invention relates to an observation lens for optical fiber fusion splicing for forming an image of an object.

[0002]

2. Description of the Related Art When an optical fiber fusion splicer is used for fusion splicing of optical fibers, it is necessary to align the end faces of the opposing optical fibers with high precision. 2. Description of the Related Art A part (opposite part between end faces to be connected) is imaged by an image sensor, image-processed, and observed by a monitor device. As an observation lens mechanism for observing the fusion spliced portion, there is a conventional observation lens mechanism 20 (referred to as Conventional Example 1) shown in FIG. The observation lens mechanism 20 has a threaded portion formed at the base of the lens barrel 21 containing the lens group 23 attached to a focus adjustment nut 24a rotatably attached to the machine frame 25 of the optical fiber fusion splicer. It is screwed and attached so that position adjustment (focus adjustment) is possible in the optical axis direction. 24b is a fixing nut.

Here, a brief description will be given of a method of observing an optical fiber connection portion using the observation lens mechanism 20. LED
(Light emitting diode) Irradiation light from 26
And the reflected light reaches an image sensor 27 such as a CCD via the observation lens mechanism 20. At this time, the focus of the observation lens mechanism 20 is focused on the fusion spliced portion of the optical fiber 28 as the observation target, and the situation (video) is sent to the monitor device (not shown) as an electric signal from the imaging device 27, and Adjusts the correct butting of the optical fibers while watching the image on the monitor device. The distance L0 between the optical fiber 28 and the imaging device 27 is called an object-image distance, and is a distance fixed to some extent by a machine. On the other hand, the focal position of the observation lens mechanism 20 is
1. By accumulating the accuracy of a plurality of components such as a lens group 23 therein and a spacing ring 29 for determining the spacing between adjacent lenses,
It varies greatly. Therefore, a focus adjustment mechanism for adjusting the position of the observation lens mechanism 20 with respect to the optical fiber 28 or the image sensor 27 is required. For this reason, for example, the above-described focus adjustment nut 24a is provided, and the focus adjustment nut 24a is turned. Then, the lens barrel 21 is moved back and forth, and the observation lens mechanism 20 is adjusted to a position where the fusion spliced portion of the optical fiber 28 is focused.

FIG. 3 shows another conventional observation lens mechanism 30 (this is referred to as Conventional Example 2). This observation lens mechanism 30
Is provided with a lens insertion opening 35 on the rear side (imaging element side) of the lens barrel 31, and the lens insertion opening 35 on the rear side is provided.
The protective glass 32, the lens group 33, the spacing ring 34, etc. are inserted from the
In this configuration, a screwing member (not shown) is screwed and fastened to 1a to fix the components in the lens barrel 31. Then, the front end surface of the lens barrel 31 is brought into contact with the reference surface S provided on the optical fiber fusion splicer side, and the position of the observation lens mechanism 30 is fixed. Therefore, the projection length of the front end 31b of the lens barrel 30 determines the focus adjustment of the observation lens mechanism 30.

When assembling the observation lens mechanism 30 to an optical fiber fusion splicer, the focusing characteristics of the observation lens mechanism 30 are evaluated after assembling the observation lens mechanism 30 and before assembling the fusion splicer. I do. That is, the observation lens mechanism 30 is placed on a focus evaluation jig that keeps the distance between the optical fiber 28 and the image sensor 27 constant (L0 is constant), and the observation lens mechanism 30 is slightly moved by a dial operation. Then, the position where the observation lens mechanism 30 is most focused is detected from the reading of the dial (this evaluates the focus characteristic of the observation lens mechanism 30).
According to the reading, it is determined how long the projection length of the front end portion 31b of the lens barrel is to be. Then, the observation lens mechanism 30 is temporarily disassembled, and the lens barrel front end portion 31b is determined based on the determination.
After the front end surface 31c of the lens barrel is polished so as to have a protruding length, the lens assembly is reassembled, and then put into the assembly process of the fusion splicer.

[0006]

Since the observation lens mechanism 20 of the prior art 1 is configured to perform focus adjustment using double nuts (24a, 24b), a large space is required around the periphery thereof. Further, in the assembling step of assembling the observation lens mechanism 20 to the optical fiber fusion splicer, it takes time and effort to adjust the focus for setting the focal position of the observation lens mechanism 20 with high precision on the fusion splicer. There is.

According to the conventional example 2, since it is not necessary to adjust the focus when assembling to the optical fiber fusion splicer, the assembly process of the fusion splicer can be saved, and the occupied space can be reduced. It has the advantage of requiring less. However, since the front end surface 31c of the lens barrel must be polished as described above, there is a problem that this polishing takes time and effort. In addition, polishing dust is generated, which may become dust on the lens, and may degrade the performance of the observation lens mechanism 30. In addition, in the observation lens mechanism of the fusion splicer, the lens group is often concentrated on the front side (the optical fiber 28 side) of the lens barrel 31, so that the lens group and the like are assembled by operating from the rear opening 35. By the way,
Assembly becomes difficult and the accuracy of assembly may be reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and does not require focus adjustment in the assembling process of the fusion splicer. It is an object of the present invention to provide an observation lens mechanism for optical fiber fusion splicing that can be assembled to a high precision optical fiber fusion splicer with a simple structure.

[0009]

According to the present invention, there is provided an optical fiber fusion splicing device which is disposed between an object to be observed and an image pickup device for observing a fusion spliced portion at the time of optical fiber fusion splicing. An observation lens mechanism for fusion splicing of an optical fiber for forming an image of the object to be observed on the image sensor, wherein a lens insertion opening is formed in a front side of a lens barrel, and a lens insertion opening on the front side is formed. The lens group inserted through the opening is formed at the front part of the inner surface of the lens barrel, and is screwed and fixed with a positioning screw member for positioning having a predetermined thickness.

According to a second aspect of the present invention, the positioning screwing member in the observation lens mechanism of the first aspect is provided with a positioning screwing member having a standard thickness and a plurality of individual positioning screwing members having different thicknesses. The observation lens mechanism for fusion splicing of an optical fiber according to claim 1.

[0011]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 shows an observation lens mechanism 10 according to an embodiment of the present invention, which is assembled at a predetermined position between an optical fiber 28 and an image sensor 27 on a fusion splicer as shown in the figure. This observation lens mechanism 10, as shown in the figure,
Front side of lens barrel 11 (observation target (optical fiber 28) side)
An opening 19 for inserting a lens is formed at the bottom, and a step 19a is provided at the back. Then, the lens group 13 is inserted from the front lens insertion opening 19 together with the spacing ring 14 that determines the lens spacing, and then the protective glass 16 is inserted.
It is configured to be formed at the front portion of the inner surface of the lens barrel 11 and fastened and fixed by a positioning screwing member 15 having a predetermined thickness H screwed to the screw portion 11a. As the positioning screwing members, a positioning screwing member having a standard thickness and a plurality of individual positioning screwing members having different thicknesses are provided.

Next, an assembly process of the observation lens mechanism 10 will be described. The predetermined lens group 13 and the spacing ring 14 are inserted through the lens insertion opening 19 on the front side of the lens barrel 11, and then the protective glass 14 is inserted. Next, the reference thickness h
Is screwed into the female threaded portion 11a of the lens barrel 11 and tightened.
3, 14, 15 are fixed in the lens barrel 11. in this way,
The observation lens mechanism 10 is once assembled.

Next, focus characteristics of the observation lens mechanism 10 once assembled are evaluated. That is, the observation lens mechanism 10 is placed on a focus evaluation jig that keeps the distance between the optical fiber 28 and the image sensor 27 constant (L2 is constant), and the observation lens mechanism 10 is operated by dial operation. While finely moving, the position where the observation lens mechanism 10 becomes the most focused point is detected from the reading of the dial (this will evaluate the focus of the observation lens mechanism 10), and according to the reading, for example, in the embodiment, protection is performed. Glass 16
Is determined from the position to the reference surface S on the fusion splicer side. Then, the positioning screw-in member 15 'having the reference thickness is removed and replaced with the positioning screw-in member 15 having the thickness of the dimension H.

Thereafter, the observation lens mechanism 10 is put into a fusion splicer assembling step. In this fusion splicer assembling step, the front end of the positioning screw member 15 attached to the lens barrel 11 of the observation lens mechanism 10 is used. The observation lens mechanism 10 is accurately focused on the fusion spliced portion (optical fiber 28) simply by touching the surface to the reference surface S on the fusion splicer side. As described above, the focus adjustment in the fusion splicer assembly process is unnecessary, and the work in the fusion splicer assembly process is labor-saving. In addition, since it is unnecessary to polish the front end surface of the lens barrel 11, there is no problem that polishing debris adheres to the lens as dust and the performance is reduced. Furthermore, in the case of a fusion splicer, the lens barrel 11
In many cases, the lens group is concentrated on the front side (optical fiber 28 side) of the lens. On the other hand, since the lens insertion opening 15 is provided on the front side of the lens barrel 11, assembly is easy and efficient. In addition, there is little possibility that the assembly accuracy will be reduced.

The arrangement of the lens groups, the spacing rings and the protective glass in the present invention is not particularly limited to that of the embodiment, but may be arbitrary. In addition, the thickness dimension of the positioning screw-in member is usually set as a dimension from the front surface of the protective glass 16, but is not necessarily limited to this as long as components in the lens barrel 11 can be tightened and fixed. Further, in the observation lens mechanism 10, while components such as lenses are concentrated on the front side of the lens barrel 11, the lens insertion opening 19 is provided on the front side of the lens barrel 11. The assembling is easy and efficient, and there is little possibility that the assembling accuracy is reduced.

[0016]

According to the observation lens mechanism for optical fiber fusion splicing of the present invention, a lens insertion opening is formed in the front side of the lens barrel, and the lens insertion opening is inserted through the front lens insertion opening. Since the lens group is formed at the front part of the inner surface of the lens barrel and screwed to the screw part, it is tightened and fixed with a positioning screwing member of a predetermined thickness, so that focus adjustment in the fusion splicer assembly process is unnecessary, Labor saving is achieved. In addition, since it is not necessary to polish the front end surface of the lens barrel, there is no problem that the polishing debris adheres to the lens as dust and the performance is reduced. Further, since the lens insertion opening is provided on the front side of the lens barrel, it is easy to assemble the observation lens mechanism, it is efficient, and there is little possibility of lowering the assembly accuracy.

According to the second aspect of the present invention, since the positioning screwing member includes a positioning screwing member having a standard thickness and a plurality of individual positioning screwing members having different thicknesses, the focus of the observation lens mechanism is adjusted. The setting work for making a predetermined one becomes easy and efficient.

[Brief description of the drawings]

FIG. 1 is a sectional view of an observation lens mechanism for fusion splicing an optical fiber according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a conventional observation lens mechanism.

FIG. 3 is a cross-sectional view of another conventional observation lens mechanism.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 observation lens mechanism 11 lens barrel 12 protective glass 13 lens group 14 spacing ring 15 positioning screw member 15 a female thread portion 15 ′ reference positioning screw member 28 optical fiber (observation target) 26 LED 27 imaging device

Claims (2)

[Claims] 1. An image processing apparatus according to claim 1, wherein the image of the observation object is formed on the image sensor for observation of a fusion splicing portion at the time of optical fiber fusion splicing. An observation lens mechanism for optical fiber fusion splicing, wherein a lens insertion opening is formed on the front side of the lens barrel, and a lens group inserted from the lens insertion opening on the front side is provided on the inner surface of the lens barrel. An observation lens mechanism for fusion splicing of an optical fiber, wherein the observation lens mechanism is fastened and fixed by a positioning screw member having a predetermined thickness, which is screwed to a screw portion to be formed at a front portion of the optical fiber. 2. The optical fiber fusion device according to claim 1, wherein said positioning screwing member comprises a positioning screwing member having a standard thickness and a plurality of individual positioning screwing members having different thicknesses. Observation lens mechanism for connection.