JP2020109426A - Protection cap - Google Patents

Abstract

To provide a protection cap capable of preventing an optical connection terminal from being contaminated even when dust exists on a wall surface or the like of a protection cap.SOLUTION: In a protection cap 200 capable of protecting an optical connection terminal assembled to an optical fiber terminal part, the protection cap comprises: a cylindrical part 211 to which the optical connection terminal can be inserted and fit; a case part in which the cylindrical part is provided on a surface thereof and, when the optical connection terminal is inserted and fit to the cylindrical part, a penetration hole is provided through which the optical connection terminal can penetrate to the inside thereof; and an adhesive part 230 that is provided inside the case part and, when the optical connection terminal is inserted and fit through the penetration hole in the case part, is disposed at a position with which a tip end of the optical connection terminal being inserted and fit thereto can come into contact.SELECTED DRAWING: Figure 2

Description

The present invention relates to a novel protective cap for protecting a connecting surface of an optical connecting terminal of an optical fiber.

During the optical fiber connection work, contamination such as dust adhering to the ferrule part (optical connection terminal) at the tip of the optical connection terminal occurs. Therefore, in the optical fiber wiring work, a protective cap is used to prevent contamination of the tip surface of the optical connection terminal.

JP, 2013-041089, A JP, 9-297244, A

However, when the conventional protective cap is used, the optical connecting terminal may be contaminated when the optical connecting terminal is mounted, such as when dust is present in the protective cap. Therefore, it is an object of the present invention to provide means for preventing contamination of the optical connection terminal even if dust is present on the wall surface of the protective cap or the like.

The present invention (1) is
A protective cap capable of protecting an optical connection terminal assembled to an optical fiber terminal,
A tubular portion having one end into which the optical connection terminal can be fitted;
A cap portion including a bottom portion provided at the other end of the tubular portion,
A position that is provided inside the cap portion and is capable of abutting the tip of the inserted optical connection terminal when the optical connection terminal is inserted into the case portion through the through hole. A protective cap having an adhesive portion disposed on the.
The present invention (2) is a protective cap capable of protecting an optical connection terminal assembled to an optical fiber terminal,
A tubular portion into which the optical connection terminal can be fitted,
The tubular portion is provided on the surface, and when the optical connection terminal is inserted into the tubular portion, a through hole through which the optical connection terminal can penetrate beyond the tubular portion to the inside is formed. The case part provided,
A position that is provided inside the case portion and is capable of contacting the tip of the inserted optical connection terminal when the optical connection terminal is inserted into the case portion through the through hole. A protective cap having an adhesive portion disposed on the.
In the present invention (3), the protective cap is
When the cap portion or the case portion is provided, and when the tip of the optical connection terminal and the adhesive portion are brought into contact with each other to emit light from the optical fiber attached to the optical connection terminal It further has a light absorption part that exhibits optical termination properties,
It is the protective cap of the invention (1) or (2).
The present invention (4) is the protective cap according to the invention (2) or (3), which is for inserting a plurality of optical connection terminals and/or optical connection terminals having different shapes.
In the present invention (5), the case part is separable into a lid part provided with the tubular part on a surface thereof and a bottom part provided with the adhesive part. It is the protective cap of (4).
The present invention (6) is the protective cap according to any one of the inventions (1) to (5), wherein the tubular portion is made of a flexible molding resin.
The present invention (7) is the protective cap according to any one of the inventions (1) to (6), wherein the material of the adhesive part is transparent, and the refractive index of the adhesive part is 1.43 to 1.55. ..
In the present invention (8), the material of the tubular portion is polyethylene (PE) and/or polypropylene (PP), and the material of the adhesive portion is an acrylic adhesive. It is the protective cap of 7).

According to the present inventions (1) and (2), in addition to (1) the function as the original protective cap, (2) the adhesive portion that comes into contact with the end of the optical connection terminal is provided in the protective cap. Even if dust is present on the end face of the optical connection terminal, the adhesive can remove the dust (cleaner function), and (3) the dust is present on the wall surface of the protective cap and the dust is lighted. Even if the dust adheres to the tip of the connection terminal, the dust can be removed by the adhesive portion (recontamination preventing function).
According to the present invention (3), in addition to the effects described above, (1) it becomes possible to add an optical terminal function to the optical connection terminal, and (2) when connector processing is applied to the end of the optical fiber, It is possible to measure the return loss for the purpose of confirming the processing state.
According to the present invention (4), in addition to the above-mentioned effect, there is an effect that a plurality of optical connection terminals can be simultaneously supported.
According to the present invention (5), in addition to the effects described above, (1) different materials can be used for the lid and the bottom {for example, a soft-retaining material (for example, PE or PP) for the lid, the bottom Can use a material that is compatible with the adhesive of the adhesive part (for example, PC, ABS, PC+ABS, etc.)}, (2) If the adhesive effect is lost, replace the bottom part with a new member to function. The effect is that can be played.
According to the present invention (6), in addition to the above effects, the close contact between the optical connection terminal and the tubular member is ensured, so that the influence of dust from the outside when the protective cap is attached to the optical connection terminal is prevented. It is possible to reduce the number and to prevent the optical connection terminal from coming off the tubular member.
According to the present invention (7), in addition to the above effects, reflection is less likely to occur at the interface between the end face of the optical connection terminal and the adhesive portion, and thus it is particularly effective when a termination function is added to the optical connection terminal. Produce an effect.
According to the present invention (8), in addition to the above effects, by using a specific material in the tubular portion and the adhesive portion, it becomes easy to press and hold the optical connection terminal into the tubular portion, and it has an excellent cleaning function and termination. It has the effect of exhibiting functions and the like.

FIG. 1 is a perspective view of an optical connection terminal assembled at the tip of an optical fiber and a side sectional view of the tip. FIG. 2 is a perspective view of the first example of the protective cap according to the present embodiment. FIG. 3 is a side sectional view showing the structure of the first example of the protective cap according to the present embodiment. FIG. 4 is an action diagram of the first example of the protective cap according to the present embodiment. FIG. 5: is a perspective view of the example 2 of an aspect of the protective cap which concerns on this form. FIG. 6 is a perspective view illustrating another aspect of the second aspect example of the protective cap according to the present embodiment. FIG. 7 is a development view of a second aspect example of the protective cap according to the present embodiment. FIG. 8 is an operation diagram of the second aspect of the protective cap according to the present embodiment.

An embodiment of the present invention will be specifically described according to the following items. The present invention is not limited to the embodiments below.
1. Protective cap 1-1. Embodiment 1 of protective cap
1-1-1. Each part 1-1-1-1. Cap section 1-1-1-1-1. Structure 1-1-1-1-2. Material 1-1-1-2. Cylindrical part 1-1-2-1. Structure 1-1-1-2-2. Material 1-1-1-3. Adhesive part 1-1-3-1. Material 1-1-1-3-2. Physical properties 1-1-1-4. Light absorption part 1-1-4-1. Material 1-1-1-2. Characteristics 1-2. Example 2 of protective cap
1-2-1. Each part 1-2-1-1. Case part 1-2-1-1-1. Structure 1-2-1-1-2. Material 1-2-1-2. Cylindrical part 1-2-1-2-1. Structure 1-2-1-2-2. Material 1-2-1-3. Adhesive part 1-2-3-1. Material 1-2-1-3-2. Physical properties 1-2-1-4. Light absorbing section 1-2-1-4-1. Material 1-2-1-2. Characteristics 1-2-2. 1. Method of manufacturing protective cap Method of using protective cap 2-1. Use as protective member 2-2. Use as cleaning member 2-3. Use as an optical termination member

1. Protective Cap A protective cap according to the present invention (eg FIGS. 2 and 5)
It is a protective cap capable of protecting the tip portion 110 of the optical connection terminal 100 (FIG. 1) assembled to the optical fiber terminal portion.

1-1. Embodiment 1 of protective cap
An example 1 of the mode according to the present invention will be described with reference to FIG.
A cap portion 210 including a tubular portion 211 into which the optical connection terminal 100 can be inserted and a bottom portion 220 provided at the other end of the tubular portion, and a cap portion 210 are provided inside the cap portion 210. Further, when the optical connection terminal is inserted into the cap portion 210 via the tubular portion 211, the adhesive is arranged at a position where the tip 111 of the inserted optical connection terminal can contact. The protective cap 200 has a portion 230.

Here, the protective cap 200 has an optical termination property when the tip 111 of the optical connection terminal 100 and the adhesive portion 230 are brought into contact with each other to emit light from an optical fiber attached to the optical connection terminal 100. You may have the light absorption part which exhibits.

The shape of the protective cap 200 is not particularly limited, and it can be manufactured according to the shape of the optical connection terminal.

1-1-1. Each part 1-1-1-1. Cap portion 1-1-2-1. Structure The cap part 210 according to the present invention includes a tubular part 211, which will be described in detail later, and a bottom part 220, and further has an adhesive part 230, which will be described later, and optionally, a light absorbing part, which will be described later in detail. You can
Further, the cap part 210 can be separated into the tubular part 211 and the bottom part 220 provided with the adhesive part 230, and can be fixed at the time of use. FIG. 2 shows an example in which the tubular portion and the bottom portion can be assembled by fitting each other. In that case, the tubular portion and the bottom portion may be fixed by a simple fitting fixing method, a fixing method using a claw, a fixing method using a screw, a fixing method by insertion fitting, a fixing method by adhesion, or the like. it can. By making the tubular portion 211 and the bottom portion 220 separable as described above, it becomes easier to use different materials for both members. For example, the material of the tubular portion 211 may be a material having excellent insertability with the tip of the optical fiber, and the material of the bottom portion 220 may be a material having excellent adhesion (adhesiveness) with the adhesive portion 230. It will be easier.

1-1-1-1-2. Material The material of the cap portion 210 is not particularly limited, and examples thereof include resin, metal, ceramics, glass and the like. The material of the tubular portion 211 and the material of the bottom portion 220 may be the same or different. It is possible to select one that matches the characteristics of each part described below.

1-1-1-2. Cylindrical part 1-1-2-1. Structure The tubular part 211 in the present invention is a main part that constitutes the cap part 210. Here, the size and shape of the tubular portion are not particularly limited, and for example, it is preferable to match the size and shape of the optical connection terminal 100 assembled to the optical fiber terminal portion or the tip portion thereof. (For example, a cylindrical shape or a rectangular tube shape). As the size and the shape of the tubular portion, the size and the shape in which the optical connection terminal is in the inserted state when the optical connection terminal is inserted are suitable, and (1) the optical connection terminal outer peripheral portion 101 of the optical connection terminal is suitable. , (2) the inner peripheral portion 102 of the concave portion of the optical connection terminal, or (3) the size and shape of the outer peripheral portion 112 of the ferrule.

In the tubular portion 211, when the optical connection terminal 100 is inserted and fitted, the tip end surface 111 of the optical connection terminal abuts on the surface of the adhesive portion 230 provided in the cap or the optical connection. The tip end surface 111 of the terminal may be designed to press the surface of the adhesive portion 230.

The tubular portion 211 can be designed to have a structure such that when the optical connecting terminal 100 is inserted and fitted, the claw portion provided on the optical connecting terminal 100 can be used for locking.

1-1-1-2-2. Material The material of the tubular portion 211 is not particularly limited, and examples thereof include metal, ceramics, resin, and glass. The material of the tubular portion 211 is preferably resin, more preferably flexible molding resin, and more preferably the adhesive portion 230, considering that the optical connection terminal 100 is repeatedly inserted and fitted and the optical connection terminal 100 is not damaged. Polyethylene resin and polypropylene resin, which have low adhesiveness with, are more preferable. Since the surface energy of polyethylene resin and polypropylene resin is relatively high, the adhesive force of the adhesive is not high. Therefore, the adhesive portion 230 can be easily peeled off from the tubular portion 211 when the adhesive portion 230 is replaced, and a portion of the adhesive portion 230 is unlikely to attach to the tubular portion 211. If extraneous matter remains in the tubular portion 211, the extraneous matter may contaminate the tip surface 111 of the optical connection terminal 100 into which the extraneous matter is inserted.

1-1-1-3. Adhesive Section The adhesive section 230 in the present invention is abutted on the tip end surface 111 of the optical connection terminal that has been inserted, or the tip end surface 111 of the optical connection terminal pushes the surface of the adhesive section 230 and then is detached. It is possible to remove dust and other contaminants adhering to the end surface 111 of the optical connection terminal.
The adhesive portion 230 has a sufficient adhesive force to remove dust and the like adhering to the optical connection terminal tip surface 111, and the optical connection terminal tip surface 111 and the optical connection terminal tip 110 that are abutted or pushed. It can be adjusted to have an internal cohesive force such that the adhesive does not adhere.

Further, the adhesive portion 230 is a substantially transparent adhesive, and can have a refractive index that is the same as or slightly higher than the refractive index of the optical fiber, as described later. Here, the term “substantially transparent” means not only a completely transparent state but also a state in which almost all incident light is transparent, for example, a state in which the light transmittance is 80% or more is transparent. By attaching the tip end surface 111 of the optical connection terminal to the adhesive section 230 or by pushing the tip end 110 of the optical connection terminal into the adhesive section 230, the light attached to the optical connection terminal The light emitted from the fiber is not reflected at the interface between the optical fiber tip and the adhesive, but can be transmitted and diffused into the adhesive. The diffused light can be absorbed by the bottom portion 220 of the cap portion 210, which is a light absorbing portion. The adhesive section 230 may have a so-called optical termination function that does not reflect the light emitted from the optical fiber to the optical fiber by being combined with a light absorbing section described later. This makes it possible to obtain a high reflection attenuation amount at the end, that is, a non-reflection state or a substantially non-reflection state, in the reflection attenuation amount measurement performed after wiring processing.

The adhesive portion 230 is provided in the cap portion 210, and the thickness thereof is not particularly limited, but is 0.05 mm or more, preferably 1 mm or more, more preferably 3 mm or more. If the thickness of the adhesive portion 230 is 3 mm or more, the pin tip does not reach the bottom even when the MPO connector having the pin is brought into contact with or pushed into the tip surface of the optical connection terminal, which is preferable. When focusing on the terminal function, the thicker the thickness of the adhesive portion 230, the easier the stable terminal function is to be exhibited.

1-1-1-3-2. Material The material of the adhesive portion 230 is not particularly limited, but an adhesive agent having a high internal cohesive force and tackiness is preferable, and a UV curing adhesive agent is more preferable in terms of ease of production and adhesive residue resistance.
Examples of the UV-curable pressure-sensitive adhesive include those containing an elastic polymer, a UV-crosslinkable resin, a polymerization initiator, a polymerization inhibitor and the like as constituent elements. Examples of the elastic polymer include acrylic resin, saturated polyester resin, polyurethane resin, and silicone resin. Among them, acrylic resin is preferable. Acrylic resins are relatively easy in arranging their physical properties in order to achieve both performances such as dust removal and adhesive residue resistance.
Examples of the acrylic resin include a copolymer of an acrylic ester monomer and another copolymerizable monomer. The copolymer uses, as the main monomer, the acrylic ester monomer capable of forming a polymer having a low glass transition point in order to impart tackiness, and also imparts internal cohesiveness. In addition, a monomer capable of forming a polymer having a high glass transition point, and a monomer having a functional group such as a carboxylic acid group, an amide group, a glycidyl group, and a hydroxyl group in order to improve crosslinkability and adhesion. Can be obtained by using

Examples of the acrylic acid ester monomers include alkyl acrylates such as ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate.

Examples of the monomer capable of forming a polymer having a high glass transition point include vinyl acetate, acrylonitrile, styrene, methyl acrylate, methyl methacrylate and the like. Examples of the monomer having a functional group such as carboxylic acid group, amide group, glycidyl group, and hydroxyl group include acrylic acid, methacrylic acid, itaconic acid, hydroxylethyl methacrylate, hydroxylpropyl methacrylate, acrylamide, and glycidyl methacrylate. Can be mentioned.

Examples of the UV-crosslinkable resin include acrylic acid ester or methacrylic acid ester as an oligomer or a monomer that is crosslinked by irradiation with ultraviolet rays in a specific wavelength range, and these include at least two acryloyl groups in a molecule or It preferably has a methacryloyl group.

Examples of the oligomer include oligoester acrylate, and examples of the monomer include 1,6-hexanediol acrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, dipentaerythritol hexaacrylate, and the like. Ester of polyhydric alcohol with acrylic acid, or ester of polyhydric alcohol such as 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, dipentaerythritol hexaacrylate and methacrylic acid Etc. can be mentioned. Besides, urethane acrylate, epoxy acrylate and the like can be mentioned.

In order to prepare the UV-curable pressure-sensitive adhesive, for example, 0.5 to 50 parts by weight, preferably 0.5 to 10 parts by weight of the UV-crosslinkable resin is added to 100 parts by weight of the elastic polymer. Good. If it is less than 0.5 parts by weight, the adhesive strength of the UV-curable adhesive may not substantially change before and after irradiation with ultraviolet rays. On the other hand, if it exceeds 50 parts by weight, the UV-cured adhesive may be cured after irradiation with ultraviolet rays. Too much and the adhesive strength may be reduced.

The polymerization initiator is used to accelerate the crosslinking of the ultraviolet-crosslinkable resin by irradiation with ultraviolet rays, and a known polymerization initiator can be used as appropriate. Examples of these polymerization initiators include benzoin alkyl ethers such as benzoin methyl ether and benzoin propyl ether, aromatic oxyketones and aromatic ketones such as benzoin, benzyl and benzophenone, benzyl dimethyl ketal, and polyvinyl benzophenone. be able to.

The amount of the polymerization initiator compounded is 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the elastic polymer. If the amount is less than 0.1 part by weight, crosslinking of the ultraviolet-crosslinkable resin does not proceed even when irradiated with ultraviolet rays, so that tackiness is less likely to be exhibited and adhesive residue is likely to occur, which may cause a problem. Even if it exceeds 20 parts by weight, the effect as a polymerization initiator does not change so much and it is not economical.

1-2-3-2. Physical Properties The pressure-sensitive adhesive preferably has a gel fraction of 60% or more, more preferably 85% or more. The degree of cross-linking is related to the cohesive force of the pressure-sensitive adhesive at room temperature or high temperature, and if the gel fraction is less than 60%, the fluidity is increased and adhesive residue is left on the tip surface 111 of the optical connection terminal. Can cause. When the gel fraction is 60 or more, the balance between adhesive residue resistance and tackiness (dust removal performance) is excellent, and the tip surface of the optical connection terminal or the tip portion contacts the adhesive portion 230 for a relatively long time. Even if it is touched or pushed in, it is difficult for the adhesive to remain.

The gel fraction is determined by using an organic solvent such as ethyl acetate as a solvent and swelling the pressure-sensitive adhesive in the solvent at a temperature of 30° C. for sufficient swelling, and then removing the insoluble matter into a 200 mesh screen. After filtering and drying the solvent, its weight can be measured and calculated by the following formula.
Gel fraction (%)=(dry weight of filtered material after immersion in solvent/weight before immersion in solvent)×100

The refractive index of the adhesive portion 230 may be the same as or slightly higher than the refractive index of the optical fiber in order to prevent reflection by the surface of the adhesive portion 230. Specifically, 1.40 to 1.65 are preferable, and 1.43 to 1.55 are more preferable. The refractive index can be measured according to JIS K7142.

1-1-1-4. Light Absorbing Section The light absorbing section according to the present invention is an optical fiber attached to the optical connecting terminal with the adhesive section 230 abutting or the tip 110 of the optical connecting terminal being pushed into the adhesive section 230. When it emits light, it exhibits optical termination.
As described above, the light emitted from the optical fiber attached to the optical connection terminal 100 is transmitted and diffused by the adhesive section 230 and absorbed by the light absorbing section.
The light absorbing part includes the cap part 210 and the bottom part 220. At least the inner surface or the outer surface of the cap part 210 is colored to absorb the light diffused by the adhesive part 230. it can.
The bottom part 220, which is the light absorbing part, may be separable from the tubular part 211. In this case, when the adhesive force of the adhesive part 230 is reduced, the adhesive part 230 and the bottom part 220 may be replaced by a new one. By replacing with, the cleaning function can be regenerated.

1-1-1-4-1. Material The material of the light absorbing part is not particularly limited, but at least the bottom part 220 itself provided with the adhesive part 230, the inner surface, or the outer surface can be colored.
The light absorbing portion may be an integrated structure made of a material that is itself colored, or a thin layer such as a paint or a film that is a different material, or a colored material, on the inner surface of the case made of a certain material. A plate material lining or the like may be provided.
The adhesive force between the light absorbing portion and the adhesive portion 230 is preferably stronger than the adhesive force between the tubular portion 211 and the adhesive portion 230. When the cleaning function of the adhesive section 230 deteriorates, the adhesive section 230 and the bottom section 220 are replaced with new ones, but at that time, the adhesive section 230 and the bottom section 220 can be replaced without leaving any adhesive on the tubular section 211 side. Will be easier. Examples of the material having a good compatibility with the adhesive portion 230 include a polycarbonate (PC) resin, an acrylonitrile-butadiene-styrene (ABS) copolymer resin, or a mixed resin of PC resin and ABS resin.
The light absorbing portion is preferably a structure made of a colored resin in view of the above and the ease of manufacturing and the cost, and a structure made of a colored PC resin, an ABS resin, or a mixed resin thereof is more preferable. It is suitable.
As the colored PC resin, ABS resin, or mixed resin thereof, those manufactured by a known manufacturing method can be used. The colorant is not particularly limited as long as it can absorb the light emitted from the optical fiber. Considering the ease of absorbing light, a black colorant is preferable, and examples thereof include carbon black and phthalocyanine blue.
The amount of the colorant added is not particularly limited, but is preferably 0.1 to 10% by weight with respect to the resin composition of the light absorbing portion.

1-1-1-2. The light transmittance of the characteristic light absorbing portion is preferably 10% or less, more preferably 2% or less, and further preferably 1% or less. The lower limit of the light transmittance is not particularly limited, but is 0.1%, for example. By setting the transmittance in such a range, a high return loss can be obtained.
The light transmittance can be measured, for example, by the following device.
The transmittance at each wavelength can be measured with a spectrophotometer UV-3100 (manufactured by Shimadzu Corporation). Table 1 shows an example of measurement conditions.

1-1-2. Method of Manufacturing Protective Cap To form the adhesive portion 230, for example, a monomer component forming the adhesive portion 230 is poured into the cap portion 210, and heating or light irradiation through the tubular portion 211 is performed to remove the monomer component. It may be formed by a method of curing (crosslinking), or the tubular portion 211 may be fitted after forming the adhesive portion 230 on the bottom portion 220 using a frame or the like.
The tubular portion 211 and the bottom portion 220 can be created by a known method. For example, extrusion molding with a mold, injection molding, or shaving from a bulk material can be used.

1-2. Example 2 of protective cap
A second example of the protective cap will be described with reference to FIG.
A tubular portion 311 into which the optical connection terminal 100 can be inserted, and the tubular portion 311 are provided on the surface, and when the optical connection terminal 100 is inserted into the tubular portion 311, the A case portion 301 having a through hole through which the optical connection terminal 100 can penetrate beyond the tubular portion 311 to the inside, and the optical connection terminal 100 is provided inside the case portion 301, and A protective cap 300 having an adhesive portion 330 arranged at a position where the tip of the inserted optical connection terminal 100 can abut when inserted into the case portion 301 through a through hole. ..

Here, the protective cap 300 is provided on the case portion 301, and is attached to the optical connection terminal 100 with the tip 110 of the optical connection terminal 100 and the adhesive portion 330 in contact with each other. You may have the light absorption part which exhibits an optical termination property when it is made to emit light from an optical fiber.

Further, the protection cap 300 may be a protection cap 300 that is compatible with a plurality of optical connection terminals 100 and/or optical connection terminals 100 having different shapes.

1-2-1. Each part 1-2-1-1. Case part 1-2-1-1-1. Structure The case portion 301 according to the present invention has a tubular portion 311 which will be described in detail later on the surface, and when the optical connecting terminal 100 is inserted into the tubular portion 311, the optical connecting terminal 100 is A through hole that penetrates the tubular portion 311 to the inside is provided, and further, an adhesive portion 330, which will be described in detail later, and optionally a light absorbing portion, which will be described later in detail, can be included. ..
Further, the case portion 301 may be separable into a lid portion 310 on which the tubular portion 311 is provided on the surface and a bottom portion 320 on which the adhesive portion 330 is provided. It can be fixed by means or the like. By making the lid portion 310 and the bottom portion 320 separable from each other, it becomes easy to use different materials for both members. For example, the material of the lid 310 having the tubular portion 311 is a material having excellent insertability with the tip of the optical fiber, and the material of the bottom 320 is a material having excellent adhesion (adhesiveness) with the adhesive section 330. It becomes easy to carry out.

1-2-1-1-2. Material The material of the case portion 301 is not particularly limited, and examples thereof include resin, metal, ceramics, glass and the like. The material of the lid 310 and the material of the bottom 320 may be the same or different. It is possible to select one that matches the characteristics of each part described below.

1-2-1-2. Cylindrical part 1-2-1-2-1. Structure The tubular portion in the present invention is provided on the surface of the case portion 301. Here, the size and shape of the tubular portion are not particularly limited, and for example, it is preferable to match the size and shape of the optical connection terminal 100 assembled to the optical fiber terminal portion or the tip portion thereof. (For example, a cylindrical shape or a rectangular tube shape). Further, regarding the aspect in which a plurality of tubular portions are provided so as to be compatible with a plurality of optical connection terminals, as shown in FIG. 5, the sizes and shapes of the respective tubular portions are respectively inserted into the plurality of tubular portions. It is also possible to use ones (for example, 311(a) to (c)) that match the sizes and shapes of the types of optical connection terminals.
Also, as shown in FIG. 6, the tubular portion has a size and a shape that match the size and shape of the same type of optical connection terminal to be inserted (for example, 311(a) to (C)}.
As the size and the shape of the tubular portion, the size and the shape in which the optical connection terminal is in the inserted state when the optical connection terminal is inserted are suitable, and (1) the optical connection terminal outer peripheral portion 101 of the optical connection terminal is suitable. , (2) the inner peripheral portion 102 of the concave portion of the optical connection terminal, or (3) the size and shape of the outer peripheral portion 112 of the ferrule.

The tubular portion 311 is designed so that, when the optical connecting terminal 100 is inserted and fitted, the tip end surface 111 of the optical connecting terminal abuts on the surface of the adhesive portion 330 provided in the case. You can

The tubular portion 311 can be designed to have a structure such that when the optical connecting terminal 100 is inserted and fitted, it can be locked by using a claw portion provided on the optical connecting terminal 100.
The tubular portion 311 may be integrally formed with the case portion or the lid portion 310, or may be a collective component manufactured and assembled as a separate component.

1-2-1-2-2. Material The material of the tubular portion 311 may be the same as or different from the material of the case portion or the lid portion 310, and is not particularly limited. For example, metal, ceramics, resin, glass, etc. are mentioned. The material of the tubular portion 311 is preferably a resin, considering that the optical connection terminal 100 is repeatedly inserted and fitted and that the optical connection terminal 100 is not damaged. It is more preferable in terms of fitting property and holding property, and polyethylene resin or polypropylene resin, which has low adhesion to the adhesive section 330, is further preferable. Since the surface energy of polyethylene resin and polypropylene resin is relatively high, the adhesive force of the adhesive is not high. Therefore, when the adhesive section 330 is replaced, it can be easily peeled off from the lid section 310, and a part of the adhesive section 330 is unlikely to adhere to the lid section 310. If any attached matter remains on the lid 310, the attached matter may contaminate the tip end surface 111 of the optical connection terminal 100 in which it is inserted, which is not preferable.

1-2-1-3. Adhesive Section The adhesive section 330 of the present invention is in contact with the inserted tip end surface 111 of the optical connection terminal, or by pushing in the tip surface 111 of the optical connection terminal and detaching the optical connection terminal. It is possible to remove contaminants such as dust attached to the tip surface 111 of the.
The adhesive portion 330 has an adhesive force sufficient to remove dust and the like adhering to the tip surface 111 of the optical connection terminal and the periphery thereof, and the optical connection terminal tip surface 111, which is abutted or pushed, It can be adjusted to have an internal cohesive force such that the adhesive does not adhere to the tip 110 of the connection terminal.

Also, the adhesive section 330 is a substantially transparent adhesive, and can have a refractive index that is the same as or slightly higher than the refractive index of the optical fiber, as described later. When the tip surface 111 of the optical connection terminal and the adhesive section 330 are brought into contact with each other or the tip 110 of the optical connection terminal is pushed into the adhesive section 330, the optical fiber attached to the optical connection terminal The light emitted from is not reflected at the interface between the tip of the optical fiber and the adhesive, but can be transmitted and diffused in the adhesive. The diffused light is absorbed by the bottom portion 320 of the case portion 301, which is a light absorbing portion. The adhesive section 330 may have a so-called optical termination function that does not reflect the light emitted from the optical fiber to the optical fiber by being combined with a light absorbing section described later. This makes it possible to obtain a high reflection attenuation amount at the terminal end, that is, a non-reflection state or a substantially non-reflection state, in the reflection attenuation amount measurement performed after wiring processing.

The adhesive portion 330 is provided in the case portion 301, and the thickness thereof is not particularly limited, but is 0.05 mm or more, preferably 1 mm or more, more preferably 3 mm or more. If the thickness of the adhesive portion 330 is 3 mm or more, the pin tip does not reach the bottom even when the MPO connector having the pin is brought into contact with or pushed into the tip surface of the optical connection terminal, which is preferable. When focusing on the termination function, the thicker the thickness of the adhesive section 330 is, the easier it is to exhibit the stable termination function.

1-2-3-1. Material The material of the adhesive portion 330 is not particularly limited, but an adhesive agent having a high internal cohesive force and tackiness is preferable, and a UV curing adhesive agent is more preferable from the viewpoint of easiness of production and adhesive residue resistance.
Examples of the UV-curable pressure-sensitive adhesive include those containing an elastic polymer, a UV-crosslinkable resin, a polymerization initiator, a polymerization inhibitor and the like as constituent elements. Examples of the elastic polymer include acrylic resin, saturated polyester resin, polyurethane resin, and silicone resin. Among them, acrylic resin is preferable. Acrylic resins are relatively easy in arranging their physical properties in order to achieve both performances such as dust removal and adhesive residue resistance.
Examples of the acrylic resin include a copolymer of an acrylic ester monomer and another copolymerizable monomer. The copolymer uses, as the main monomer, the acrylic ester monomer capable of forming a polymer having a low glass transition point in order to impart tackiness, and also imparts internal cohesiveness. In addition, a monomer capable of forming a polymer having a high glass transition point, and a monomer having a functional group such as a carboxylic acid group, an amide group, a glycidyl group, and a hydroxyl group in order to improve crosslinkability and adhesion. Can be obtained by using

Examples of the acrylic acid ester monomers include alkyl acrylates such as ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate.

Examples of the monomer capable of forming a polymer having a high glass transition point include vinyl acetate, acrylonitrile, styrene, methyl acrylate, methyl methacrylate and the like. Examples of the monomer having a functional group such as carboxylic acid group, amide group, glycidyl group, and hydroxyl group include acrylic acid, methacrylic acid, itaconic acid, hydroxylethyl methacrylate, hydroxylpropyl methacrylate, acrylamide, and glycidyl methacrylate. Can be mentioned.

Examples of the UV-crosslinkable resin include oligomers that crosslink by irradiation with UV in a specific wavelength range, or acrylic acid esters or methacrylic acid esters as monomers, and these include at least 2 in the molecule. It is preferable to have one acryloyl group or a methacryloyl group.

Examples of the oligomer include oligoester acrylate, and examples of the monomer include 1,6-hexanediol acrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, dipentaerythritol hexaacrylate, and the like. Ester of polyhydric alcohol with acrylic acid, or ester of polyhydric alcohol such as 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, dipentaerythritol hexaacrylate and methacrylic acid Etc. can be mentioned. Besides, urethane acrylate, epoxy acrylate and the like can be mentioned.

In order to prepare the UV-curable pressure-sensitive adhesive, for example, 0.5 to 50 parts by weight, preferably 0.5 to 10 parts by weight of the UV-crosslinkable resin is added to 100 parts by weight of the elastic polymer. Good. If it is less than 0.5 parts by weight, the adhesive strength of the UV-curable adhesive may not substantially change before and after irradiation with ultraviolet rays. On the other hand, if it exceeds 50 parts by weight, the UV-cured adhesive may be cured after irradiation with ultraviolet rays. Too much and the adhesive strength may be reduced.

The polymerization initiator is used to accelerate the crosslinking of the ultraviolet-crosslinkable resin by irradiation with ultraviolet rays, and a known polymerization initiator can be used as appropriate. Examples of these polymerization initiators include benzoin alkyl ethers such as benzoin methyl ether and benzoin propyl ether, aromatic oxyketones and aromatic ketones such as benzoin, benzyl and benzophenone, benzyl dimethyl ketal, and polyvinyl benzophenone. be able to.

The amount of the polymerization initiator compounded is 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the elastic polymer. If the amount is less than 0.1 part by weight, crosslinking of the ultraviolet-crosslinkable resin does not proceed even when irradiated with ultraviolet rays, so that tackiness is less likely to be exhibited and adhesive residue is likely to occur, which may cause a problem. Even if it exceeds 20 parts by weight, the effect as a polymerization initiator does not change so much and it is not economical.

1-2-1-3-2. Physical Properties The pressure-sensitive adhesive preferably has a gel fraction of 60% or more, more preferably 85% or more. The degree of cross-linking is related to the cohesive force of the pressure-sensitive adhesive at room temperature or high temperature, and if the gel fraction is less than 60%, the fluidity is increased, and the tip surface 111 of the optical connection terminal is increased. May cause glue residue. When the gel fraction is 60 or more, the balance between adhesive residue resistance and tackiness (dust removal performance) is excellent, and the tip surface of the optical connection terminal or the tip portion of the optical connecting terminal is adhered to the adhesive portion 230 for a relatively long time. It is difficult for the adhesive to remain even if it comes into contact with or is pushed into.

The gel fraction is determined by using an organic solvent such as ethyl acetate as a solvent and swelling the pressure-sensitive adhesive in the solvent at a temperature of 30° C. for sufficient swelling, and then removing the insoluble matter into a 200 mesh screen. After filtering and drying the solvent, its weight can be measured and calculated by the following formula.
Gel fraction (%)=(dry weight of filtered material after immersion in solvent/weight before immersion in solvent)×100

The refractive index of the adhesive portion 230 may be the same as or slightly higher than the refractive index of the optical fiber in order to prevent reflection by the surface of the adhesive portion 230. Specifically, 1.40 to 1.65 are preferable, and 1.43 to 1.55 are more preferable. The refractive index can be measured according to JIS K7142.

1-2-1-4. Light Absorbing Portion The light absorbing portion according to the present invention is attached to the optical connecting terminal in contact with the adhesive portion 330 or with the tip 110 of the optical connecting terminal being pushed into the adhesive portion 330. It exhibits optical termination when light is emitted from the fiber.
As described above, the light emitted from the optical fiber attached to the optical connection terminal 100 is transmitted and diffused by the adhesive section 330 and absorbed by the light absorbing section.
The light absorbing part is the bottom part 320 of the case part 301, and at least the case 301 itself on which the adhesive part 330 is provided, the inner surface, or the outer surface is colored to diffuse in the adhesive part 330. The emitted light can be absorbed.
The bottom part 320, which is the light absorbing part, may be separable from the lid part 310. In this case, when the adhesive force of the adhesive part 330 is reduced, the adhesive part 330 and the bottom part 320 are replaced with a new one. The cleaning function can be regenerated by replacing it.

1-2-4-1. Material The material of the light absorbing portion is not particularly limited, but at least the bottom portion 320 where the adhesive portion 330 is provided, the inner surface, or the outer surface can be colored.
The light absorbing part may be a structure made of a material that is itself colored, or a thin film layer such as a paint or a film that is another material, or a colored material, on the inner surface of the case made of a certain material. A plate material lining or the like may be provided.
The adhesive force between the light absorbing part and the adhesive part 330 is preferably stronger than the adhesive force between the lid part 310 and the adhesive part 330. When the cleaning function of the adhesive section 330 deteriorates, the adhesive section 330 and the bottom section 320 are replaced with new ones. At that time, the adhesive section 330 and the bottom section 320 can be replaced without leaving any adhesive on the lid section 310 side. It will be easy. Examples of the material having a good compatibility with the adhesive portion 330 include a polycarbonate (PC) resin, an acrylonitrile-butadiene-styrene (ABS) copolymer resin, a mixed resin of PC resin and ABS resin, and the like.
The light absorbing portion is preferably a structure made of a colored resin in view of the above and the ease of manufacturing and the cost, and a structure made of a colored PC resin, an ABS resin, or a mixed resin thereof is more preferable. It is suitable.
As the colored PC resin, ABS resin, or mixed resin thereof, those manufactured by a known manufacturing method can be used. The colorant is not particularly limited as long as it can absorb the light emitted from the optical fiber. Considering the ease of absorbing light, a black colorant is preferable, and examples thereof include carbon black and phthalocyanine blue.
The amount of the colorant added is not particularly limited, but is preferably 0.1 to 10% by weight with respect to the resin composition of the light absorbing portion.

1-2-1-2. The light transmittance of the characteristic light absorbing portion is preferably 10% or less, more preferably 2% or less, and further preferably 1% or less. The lower limit of the light transmittance is not particularly limited, but is 0.1%, for example. By setting the transmittance in such a range, a high return loss can be obtained.
The light transmittance can be measured, for example, by the following device.
The transmittance at each wavelength can be measured with a spectrophotometer UV-3100 (manufactured by Shimadzu Corporation). Table 1 shows an example of measurement conditions.

2. Method of Manufacturing Protective Cap The formation of the adhesive portion 330 may be performed according to the material and the like. For example, the monomer component forming the adhesive portion 330 is poured into the bottom portion 320, and heating or light irradiation is performed to form the monomer component. May be formed by a method of curing (crosslinking). After forming the adhesive portion 230, the cover portion 310 is covered, and the adhesive portion 330 is covered, so that the protective cap 300 can be manufactured.
Further, in the case where the case portion 301 cannot be separated, a monomer component is introduced from the through hole of the tubular portion 311 to fill the inside of the case portion with the monomer component, and ultraviolet rays are irradiated through the through hole of the tubular portion 311. The adhesive section 330 can also be formed.
The lid part 310, the bottom part 320 and the like can be manufactured by a known method. For example, extrusion molding with a mold, injection molding, or shaving from a bulk material can be used.

3. Method of Using Protective Cap The method of using the protective cap will be described below with reference to FIGS. 4 and 8. The protection cap is used as a terminal block for protecting, cleaning, and measuring the return loss of the optical connection terminal 100 by an operation of attaching or detaching the optical connection terminal 100 to or from the protection cap 200 (300). That complicated operation can be omitted. That is, the worker can save the labor of detaching the optical connection terminal 100 from the protective cap 200 (300) every time when cleaning or measuring the return loss in the optical fiber connection work, and the work efficiency can be improved. it can.

The operation of each function of the protective cap 200 (300) according to the present invention will be described below individually.
3-1. Action as Protective Member The protective cap 200 (300) according to the present invention uses the tubular portion 211 (311) manufactured according to the shape of the optical connection terminal 100 assembled to the optical fiber terminal portion as a guide, for example, as an optical member. The tip portion 110 of the connection terminal can be used by inserting it into the tubular portion 211 (311).
The tip portion 110 of the optical connection terminal penetrates the tubular portion 211 (311) along the inner edge of the tubular portion 211 (311), and the adhesive portion 230 accommodated in the cap portion or the case portion. It can abut or be pushed into (330).
The optical connection terminal 100 is locked by being fitted to the inserted tubular portion 211 (311). As a result, the optical connection terminal 100 is completely covered by the tubular portion 211 (311), and is thus protected from external damage.
At the same time, it is possible to prevent contaminants such as dust from entering, and the optical connection terminal 100 is also protected from contamination.
The optical connection terminal 100 can be removed by pulling it out from the inserted cylindrical portion 211 (311).
The tubular portion 211 (311) can be repeatedly used by inserting the same or another optical connection terminal 100.

3-2. Action as Cleaning Member The protective cap 200 (300) according to the present invention uses the tubular portion of the optical connection terminal 100 assembled to the optical fiber terminal portion as a guide, using the tubular portion manufactured according to the shape as a guide. 110 can be inserted into the tubular portion 211 (311) and used.
The tip portion 110 of the optical connection terminal is arranged along the inner edge of the tubular portion 211 (311) via the tubular portion 211 (311), and the adhesive portion 230 (330) housed in the cap portion or the case portion. ), or can be pushed in.
The optical connection terminal 100 can be locked by being fitted to the inserted tubular portion 211 (311).
At this time, the dust adhering to the optical connection terminal tip portion 110 or the optical connection terminal tip surface 111 is transferred to the adhesive portion 230 (330).
When the optical connection terminal 100 is detached, the optical connection terminal tip portion 110 and the optical connection terminal tip surface 111 can be provided in a clean state.
As a result, the operator does not need to clean the optical connection terminal tip portion 110 or the optical connection terminal tip surface 111 again, and the working efficiency can be improved.

In addition, the adhesive section 230 (330) can be used repeatedly, and the adhesive strength decreases as the frequency of use increases. That is, the cleaning ability is reduced. In that case, by removing the bottom part 220 (320) provided with the adhesive part 230 (330), it becomes possible to replace it with a new adhesive part 230 (330) and the bottom part 220 (320), and the cleaning ability is improved. Can be recovered.

3-3. Action as Optical Termination Member The protective cap 200 (300) according to the present invention uses the tubular portion 211 (311) manufactured according to the shape of the optical connection terminal 100 assembled to the optical fiber terminal portion as a guide to guide light. The tip portion of the connection terminal can be used by inserting it into the tubular portion 211 (311).

The tip portion 110 of the optical connection terminal contacts the adhesive portion 230 (330) housed inside along the inner edge of the tubular portion 211 (311) via the tubular portion 211 (311), Or it can be pushed.
The optical connection terminal 100 is locked by being fitted to the inserted tubular portion 211 (311).

In this state, the light emitted from the optical fiber attached to the optical connection terminal 100 is transmitted and diffused by the adhesive section 230 (330) and is absorbed by the light absorption section.
As a result, the protective cap 200 (300) can be used as a terminal block, and reflection on the end face of the connector can be excluded to perform reflection attenuation amount measurement in a non-reflection state.
Therefore, the operator removes the optical connection terminal 100 from the protective cap 200 (300), presses it against the terminal block, measures the return loss, and then attaches the protective cap 200 (300), which is a complicated conventional work. Can be omitted.
Further, when the protective cap of the present invention has an optical terminal function, it can be held in the backyard with the protective cap of the present invention attached to the spare wiring of the optical fiber. Thus, for example, when some trouble occurs in the used wiring, it can be immediately replaced with the spare wiring.

<<Example>>
Hereinafter, the present invention will be described based on Examples and Comparative Examples, but the present invention is not limited to the contents of the Examples. The following example is an example implemented according to the second aspect of the protective cap described above.

<Preparation of protective cap>
The lid 310 was made by molding PE resin. The tubular portion has a shape to be fitted with an SC connector (compliant with IEC6175-4) which is an optical connection terminal used for measurement, and an outer diameter portion of a ferrule provided in the LC connector (compliant with IEC6175-4), It was manufactured by integral molding. The height of the cylindrical portion was 4 mm with respect to the length of the ferrule of 5.8 mm, and the front end surface of the ferrule (front end surface 111 of the optical connection terminal) was brought into contact with the internal adhesive portion 330.

The following composition was used as the adhesive used for the adhesive section 330.
Elastic polymer: Toagosei Co., Ltd., 2-EHA 100 parts by weight UV cross-linking resin: Daicel Ornex Co., Ltd., HDDA 1 part by weight UV polymerization initiator: BASF, Irgacure 184 1 part by weight UV curing aid: 0.1 parts by weight of Karenz MT PE1 manufactured by Showa Denko KK The above composition was poured into a bottom portion 320 described later to fill the bottom portion 320.
Subsequently, the composition was cured by irradiating it with ultraviolet rays to form an adhesive portion 330 having a thickness of 300 μm. The gel fraction of the adhesive section 330 was 95%. The refractive index was 1.47.

The bottom portion 320 was made by molding a colored ABS resin by adding 1% by weight of carbon black to the ABS resin to form a light absorbing portion.

The protective cap manufactured as described above was used as Example 1.

Example 2 was the same as Example 1 except that the composition of the adhesive part was changed as follows and the refractive index was adjusted to 1.44 by mixing a low refractive index resin. ..
Elastic polymer: Toagosei Co., Ltd., 2-EHA 100 parts by weight UV cross-linking resin: DIC Corporation, Defencer OP-4004 100 parts by weight UV polymerization initiator: BASF, Irgacure 184 1 part by weight UV curing auxiliary agent : Showa Denko KK, Karenz MT PE1 0.1 part by weight

Examples 3 to 5 were similar to Example 1 except that only the thickness of the adhesive portion was changed as shown in Table 2.

Example 6 was the same as Example 1 except that the cylindrical portion was made of ABS resin.

Example 7 was the same as Example 1 except that the UV irradiation condition was changed to set the gel fraction to 78%.

In Comparative Example 1, a protective cap similar to that of Example 1 was produced, and the ferrule tip end face was not brought into contact with the adhesive portion.

<Method of measuring return loss>
For the light reflection measurement, single-core measurement and multi-core measurement were performed.
In the case of a single core, the SC connector was attached to both ends of a single-core silica single mode optical fiber UV core wire (manufactured by Sumitomo Electric Co., Ltd., outer shape: 0.25 mmφ, refractive index: 1.452 at 20° C.). One of the SC connectors was connected to a return loss measurement device (JD Uniphase reflection meter RM3750+1FA7), the other SC connector was fitted to the above-mentioned tubular portion 221, and the return loss was measured with the single mode wavelength set to 1310 nm. did.
In the case of multiple cores, a 12-core silica single-mode optical fiber tape core wire (Sumitomo Electric Co., Ltd., outer diameter 0.25 mmφ, refractive index 1.452 at 20° C.) is used as one end fan-out wiring and 8 An SC connector was attached and an MT connector was applied to the other end. The SC connector side was connected to a return loss measuring device (reflection meter RM3750+1FA7 manufactured by JD Uniphase), the MT connector was pressed against the above optical termination film, and the return loss was measured at a single mode wavelength of 1310 nm.

<Evaluation of cleaning function>
After spraying the AC dust Fine (manufactured by Japan Powder Industry Technology Association) sucked into the dropper onto the end face of the evaluation connector (end face of the MPO connector with guide pins), the excess dust is shaken off, and the evaluation sample is prepared. I prepared 30 pieces. The evaluation connector was inserted from the tubular portion, and the end face of the evaluation connector was brought into contact with the evaluation sample. After leaving still for about 2 seconds, the evaluation connector was pulled up from the tubular portion, and the connecting end surface of the connector was observed with a microscope (in the case of a connector having a pin, the peripheral surface of the pin was observed).
The above operation was performed on 30 samples, and the cleaning function was evaluated according to the following evaluation criteria.
A: Dust was sufficiently removed from all the samples.
B: Dust remains in one or more samples.

<Evaluation of adhesive residue on adhesive>
The evaluation connector was inserted from the tubular portion, and the end face of the evaluation connector was brought into contact with the evaluation sample. After leaving still for about 2 seconds, the evaluation connector was pulled up from the tubular portion, and the connection end face of the optical connector was observed with a microscope (in the case of a connector having a pin, the peripheral face of the pin was observed). The above operation was carried out for 30 connectors, and the adhesive residual adhesive property was evaluated according to the following evaluation criteria.
A: No adhesive residue is observed in any of the connectors.
B: Adhesive residue is slightly observed on one or more connectors.
C: Adhesive residue is observed in one or more connectors.

Table 2

<Evaluation result>
In all of the examples, good results were obtained in terms of cleanability and adhesive paste residue. Further, it was revealed that the thicker the adhesive portion, the higher the termination performance. In addition, in Example 6 in which the material of the cylindrical portion is changed to ABS resin, there is no difference in the performance in the table, but since ABS resin is harder than PE resin, relative operability in attachment/detachment of the optical connection terminal is relatively high. It became clear that it was bad (difficult to insert and remove).
On the other hand, in the comparative example, it was revealed that the cleaning ability could not be exhibited because it did not contact the adhesive portion, and the terminal performance was remarkably low.
From the above, the usefulness of the protective cap according to the present invention can be understood.

100 Optical Connection Terminal 111 Tip Surface of Optical Connection Terminal 200 Protective Cap 210 Cap Part 310 Lids 211, 311 Cylindrical Parts 220, 320 Bottom Part (Light Absorption Part)
230, 330 Adhesive part

Claims (8)

A protective cap capable of protecting an optical connection terminal assembled to an optical fiber terminal,
A tubular portion having one end into which the optical connection terminal can be fitted;
A cap portion including a bottom portion provided at the other end of the tubular portion,
The optical connection terminal is provided inside the cap portion, and when the optical connection terminal is inserted into the cap portion through the above, it is arranged at a position where the tip of the inserted optical connection terminal can contact. A protective cap having an adhesive part formed thereon. A protective cap capable of protecting an optical connection terminal assembled to an optical fiber terminal,
A tubular portion into which the optical connection terminal can be fitted,
The tubular portion is provided on the surface, and when the optical connection terminal is inserted into the tubular portion, a through hole through which the optical connection terminal can penetrate to the inside beyond the tubular portion is provided. The case part provided,
A position that is provided inside the case portion and is capable of contacting the tip of the inserted optical connection terminal when the optical connection terminal is inserted into the case portion through the through hole. A protective cap having an adhesive portion disposed on the. The protective cap is
When the cap portion or the case portion is provided, and when the tip of the optical connection terminal and the adhesive portion are brought into contact with each other to emit light from the optical fiber attached to the optical connection terminal The protective cap according to claim 1 or 2, further comprising a light absorbing portion exhibiting a light terminating property. The protective cap according to claim 2 or 3, which is for inserting a plurality of optical connection terminals and/or optical connection terminals having different shapes. The protection according to any one of claims 2 to 4, wherein the case part is separable into a lid part provided with the tubular part on a surface thereof and a bottom part provided with the adhesive part. cap. The protective cap according to claim 1, wherein the tubular portion is made of a flexible molding resin. The protective cap according to any one of claims 1 to 6, wherein the material of the adhesive portion is transparent, and the refractive index of the adhesive portion is 1.43 to 1.55. The protective cap according to claim 1, wherein the material of the tubular portion is polyethylene and/or polypropylene, and the material of the adhesive portion is an acrylic adhesive.

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