Optical fiber ribbon

Abstract

To provide an intermittently bonded optical fiber ribbon that is excellent in handling properties, and can suppress crack propagation of an adhesion part and has higher reliability than the prior art.SOLUTION: An optical fiber ribbon 1 is configured such that a plurality of optical fiber strands 3a, 3b, 3c, and 3d are bonded in parallel. In the optical fiber ribbon 1, each of the adjacent optical fiber strands 3a, 3b, 3c, and 3d is intermittently bonded to each other with adhesion parts 5 with a predetermined interval spaced in a lengthwise direction. The adjacent optical fiber strands are continuously bonded to each other in the adhesion parts 5 on one side (upper surface side) of the optical fiber ribbon 1. On the other hand, in the adhesion parts 5 on the other side (lower surface side) of the optical fiber ribbon 1, deficient parts 5b are formed in parts of the adhesion part and there exist portions in which bonded portions are not continuously formed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical fiber ribbon in which a plurality of optical fiber strands are bonded in parallel. [Background technology]

[0002] As an optical fiber for transmitting a large amount of data at high speed, an optical fiber ribbon is used in which multiple optical fiber strands are arranged in parallel and adjacent optical fiber strands are bonded together to simplify storage in a cable and work. Optical fiber ribbons include those in which parallel optical fiber strands are fixed over their entire length with resin, and those in which optical fiber strands are intermittently bonded together in the longitudinal direction. Intermittent bonding of optical fiber strands has the characteristics of improving the wire collection density, reducing transmission loss due to bending, and making it easier to make them single-core.

[0003] On the other hand, in such an intermittently bonded optical fiber ribbon, an optical fiber ribbon has been proposed in which the intermittently arranged bonded parts are not bonded uniformly and continuously. For example, an intermittently bonded optical fiber ribbon has been proposed in which the bonded parts are not uniformly continuous, but are composed of two or more partial connection parts spaced at a predetermined interval (Patent Document 1).

[0004] In the optical fiber ribbon of Patent Document 1, the interval between the partial connection parts in the adhesive part is set to be equal to or larger than the outer diameter of the optical fiber. With such an optical fiber ribbon, a splitting tool (brush) can be easily inserted between the partial connection parts during single-core splitting, which prevents an increase in optical loss and facilitates the splitting of the optical fiber.

[0005] Also, an optical fiber ribbon has been proposed in which the bonded portion is formed as a collection of multiple small bonded portions, with non-bonded portions provided between the small bonded portions (Patent Document 2). This makes it difficult for a crack that occurs in one part of the bonded portion to propagate throughout the entire bonded portion, making it possible to suppress unintended breakage of the bonded portion. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-215493 A [Patent Document 2] JP 2016-177102 A Summary of the Invention [Problem to be solved by the invention]

[0007] In this way, as in Patent Documents 1 and 2, by forming partially unbonded areas among the intermittently arranged bonded joints, it is possible to obtain the effects of improving the ease of separation work and, even if a crack unintentionally occurs in one part of the bonded joint, the crack will not propagate throughout the entire joint, thereby suppressing breakage.

[0008] However, in both Patent Document 1 and Patent Document 2, there is a gap between the connecting parts that is not bonded, and therefore, during manufacturing or operation, other materials (e.g., fibers, etc.) may get into the gap and the bonded part may break unintentionally. This may cause the single cores to come apart during the work of separating the single cores, making it impossible to identify the single cores. In addition, there is a possibility that loss will increase due to microbending loss, since there are periodically formed parts that are not completely coated with resin and parts that are coated with resin.

[0009] The present invention has been made in consideration of such problems, and aims to provide an intermittently bonded optical fiber ribbon that is easy to handle, can suppress the propagation of cracks in the bonded joint, and is more reliable. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the present invention provides an optical fiber ribbon having a plurality of optical fiber strands arranged in parallel, wherein at least some of the adjacent optical fiber strands are intermittently bonded to each other at bonding sections formed at predetermined intervals in the longitudinal direction of the optical fiber ribbon,the adhesive portions on one side and the other side of the optical fiber ribbon are provided at substantially the same positions in the longitudinal direction of the optical fiber ribbon, This optical fiber ribbon is characterized in that the adhesive portion on one side of the optical fiber ribbon is formed by continuously bonding adjacent optical fiber strands, and the adhesive portion on the other side of the optical fiber ribbon has a missing portion in part, so that the connection portion is not continuous.

[0011] It is desirable that the length of the defect be 0.2 mm or more and 3 mm or less.

[0012] According to the present invention, since the adhesive on one side is not completely continuous and a missing portion is formed, the above-mentioned improvement in the ease of separation and the effect of suppressing crack propagation can be obtained. Also, compared with the case where the adhesive is formed entirely continuously, the amount of adhesive used can be reduced. In other words, the same effects as those of Patent Documents 1 and 2 mentioned above can be obtained.

[0013] On the other hand, since the adhesive portion is continuously formed on the other side of the optical fiber ribbon, even if other materials (fibers, etc.) get into the defective portion during manufacturing or operation, it is possible to prevent the optical fiber strand from being unintentionally split at that portion.

[0014] Such an effect is particularly effective when the length of the defect is 0.2 mm or more and 3 mm or less. For example, if the length of the defect is too short, the effect of forming the defect is small, and if the length of the defect is too long, the adhesive strength of the adhesive part is reduced. Effect of the Invention

[0015] According to the present invention, it is possible to provide an intermittently bonded optical fiber ribbon or the like which is easy to handle, can suppress the propagation of cracks in the bonded portion, and has high reliability. [Brief description of the drawings]

[0016] [Figure 1] 1A is a top perspective view showing the optical fiber ribbon 1, and FIG. 1B is a bottom perspective view showing the optical fiber ribbon 1. FIG. [Diagram 2] 1A is a diagram showing the positional relationship between the top and bottom surfaces of the optical fiber ribbon 1, and FIG. 1B is an enlarged view of part A in FIG. [Diagram 3] FIG. 2A is a top perspective view showing the optical fiber ribbon 1a, and FIG. 2B is a bottom perspective view showing the optical fiber ribbon 1a. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1(a) is a top perspective view showing an optical fiber ribbon 1, and Fig. 1(b) is a bottom perspective view showing the optical fiber ribbon 1.

[0018] The optical fiber ribbon 1 is configured by bonding a plurality of optical fiber strands 3a, 3b, 3c, and 3d in parallel. In this embodiment, an example is shown in which the optical fiber ribbon 1 is configured by four optical fiber strands 3a, 3b, 3c, and 3d, but the present invention is not limited to this, and the number of optical fiber strands is not particularly limited as long as the optical fiber ribbon has a plurality of optical fiber strands arranged in parallel. In addition, in the present invention, each single optical fiber strand that configures the optical fiber ribbon 1 is simply referred to as an optical fiber strand.

[0019] In the optical fiber ribbon 1, adjacent optical fiber strands 3a, 3b, 3c, and 3d are bonded to each other at predetermined intervals in the longitudinal direction by intermittently arranged bonding parts 5. The bonding parts 5 of adjacent optical fiber strands are arranged, for example, in a staggered manner with respect to the longitudinal direction of the optical fiber ribbon 1.

[0020] That is, the bonding position (bonding portion 5) between the optical fiber strands 3b, 3c in the longitudinal direction of the optical fiber ribbon 1 is shifted by approximately half a pitch from the bonding positions (bonding portions 5) between the adjacent optical fiber strands 3a, 3b and between the adjacent optical fiber strands 3c, 3d. Therefore, the bonding position between the optical fiber strands 3a, 3b and the bonding position between the optical fiber strands 3c, 3d are the same position.

[0021] The adhesive portions 5 of adjacent optical fiber strands are all formed at substantially the same pitch in the longitudinal direction of the optical fiber ribbon 1. Therefore, the arrangement of the optical fiber strands is not disturbed when the optical fiber ribbon 1 is installed.

[0022] Here, adjacent optical fiber strands are continuously bonded to each other in the bonding portion 5 on one side (upper surface side) of the optical fiber ribbon 1. That is, within the range of the bonding portion 5 on one side (upper surface side) of the optical fiber ribbon 1, there are no unbonded portions, and adjacent optical fiber strands are bonded to each other over the entire range of the bonding portion 5.

[0023] On the other hand, a missing portion 5b is formed in a part of the adhesive portion 5 on the other side (lower surface side) of the optical fiber ribbon 1, and there is a portion where the adhesive portions (connecting portions 5a) are not continuous. That is, within the range of the adhesive portion 5 on the other side (lower surface side) of the optical fiber ribbon 1, there are formed connecting portions 5a where adjacent optical fiber strands are bonded together, and missing portions 5b where adjacent optical fiber strands are not bonded together.

[0024] In this way, the optical fiber ribbon 1 has different shapes of the adhesive parts 5 on the upper and lower sides (front and back sides), with the adhesive part 5 on one side being formed continuously (i.e., all of it is a connecting part), and the adhesive part 5 on the other side being composed of a plurality of connecting parts 5a formed intermittently, for example in a dot-like manner at a predetermined pitch in the longitudinal direction of the optical fiber ribbon 1.

[0025] In Fig. 2(a), the upper figure is a plan view, and the lower figure is a bottom view, showing a state in which the longitudinal positions of the adhesive portions 5 on the upper and lower surfaces correspond to each other. As shown in the figure, the forming positions and forming areas of the adhesive portions 5 are the same on the upper and lower surfaces of the optical fiber ribbon 1. That is, on the back surface of the adhesive portions 5 formed continuously on the upper surface, the connecting portions 5a and the missing portions 5b are arranged. Conversely, on the back surface side of the portions other than the adhesive portions 5 (non-adhesive portions) on the upper surface, the connecting portions 5a and the missing portions 5b between the connecting portions 5a are not arranged, and they become non-adhesive portions.

[0026] FIG. 2(b) is an enlarged view of part A in FIG. 2(a). The length C of the missing portion 5b in the longitudinal direction is desirably 0.2 mm or more and 3 mm or less. If the length C of the missing portion 5b is less than 0.2 mm, the effect of forming the missing portion 5b is reduced. If the length C of the missing portion 5b exceeds 3 mm, the connecting portion 5a becomes relatively short, and the adhesive strength of the adhesive portion 5 decreases. For this reason, the adhesive portion 5 is more likely to be separated unexpectedly during manufacturing or installation work. The length of the missing portion 5b is shorter than the length of the pitch (non-adhesive portion) of the adhesive portion 5.

[0027] In addition, it is desirable that the length B of the connecting portion 5a in the longitudinal direction is 0.2 mm or more and 3 mm or less. If the length B of the connecting portion 5a is less than 0.2 mm, the amount of adhesive filled in the cross-sectional direction is also reduced, and the adhesive strength of the connecting portion 5a is weakened. Therefore, the adhesive portion 5 is more likely to be separated unexpectedly during manufacturing or installation work. Conversely, if the length B of the connecting portion 5a exceeds 3 mm, the effect of forming the missing portion 5b is reduced.

[0028] The number and shape of the connecting portions 5a in the adhesive portion 5 are not limited to the illustrated example. The pitch and size of the adhesive portions 5 and the connecting portions 5a are not limited to the illustrated example. For example, the shape of the connecting portions 5a does not have to be circular as illustrated, and may be an ellipse, oval, rectangle, or the like having a longer adhesive margin in the longitudinal direction of the optical fiber ribbon 1.

[0029] In the illustrated example, the connecting portions 5a are formed at a substantially constant pitch, but the present invention is not limited to this. For example, it is sufficient that at least one missing portion 5b is formed within the adhesive portion 5, and even if multiple missing portions 5b are formed, the pitch and length of the missing portions 5b (i.e., the length and interval of the connecting portions 5a) may be random.

[0030] Next, a method for manufacturing an optical fiber ribbon will be described. First, a predetermined number of optical fibers are individually fed from a supply drum and collected in parallel by a concentrator or the like. An adhesive (resin) is intermittently applied to the parallel optical fibers at predetermined positions in the longitudinal direction by a coating device such as a coating roll.

[0031] Here, the adhesive portions 5 can be intermittently formed in the longitudinal direction by, for example, intermittently applying an adhesive with an applicator. The applied adhesive can be cured by a curing device such as an ultraviolet ray irradiation device to form the adhesive portions 5. The method for intermittently arranging the adhesive portions 5 is not particularly limited, and may include a method of applying the adhesive over the entire length, followed by mechanically cutting with a blade, or a method of chemically removing the adhesive with a solution.

[0032] Next, a method for forming a continuous adhesive portion 5 on the upper surface and a connecting portion 5a and a missing portion 5b on the lower surface will be described. A method for changing the shape of the adhesive portion 5 on the upper and lower surfaces of the optical fiber ribbon 1 includes changing the coating conditions of coating devices installed on the upper and lower surfaces of the optical fiber ribbon 1. For example, there is a method for disposing coating rolls of different shapes separately on the upper and lower surfaces. Note that, as long as a missing portion can be formed in part of the adhesive portion 5 on one surface, the coating device may be disposed on only one side, and the manufacturing method is not particularly limited.

[0033] In this manner, the optical fiber ribbon 1 having the adhesive portion 5 with a different shape on one side is manufactured. After that, the optical fiber ribbon 1 is wound up by a winding device. Note that the manufacturing method of the optical fiber ribbon 1 is not limited to the above-mentioned example, and any method may be used.

[0034] As described above, according to this embodiment, on one side of the optical fiber ribbon 1, the adhesive portion 5 that connects the optical fiber strands is formed of a plurality of connecting portions 5a and a missing portion 5b. Therefore, the propagation of a crack that starts from a notch or the like generated in one connecting portion 5a can be stopped by the missing portion 5b. Therefore, the adhesive portion 5 can be prevented from being broken in its entirety.

[0035] In addition, by providing the connecting portion 5a and the cutout portion 5b in this manner, a tool (brush) or the like can be inserted into the cutout portion 5b, making the separation work easy. In addition, by partially providing the cutout portion 5b in the adhesive portion 5, the amount of adhesive used can be reduced.

[0036] Furthermore, since the adhesive portion 5 is continuous on the opposite side of the optical fiber ribbon 1, even if a foreign object or the like is unintentionally caught in the defective portion 5b, causing the connecting portion 5a to break, it is possible to prevent the entire adhesive portion 5 from immediately breaking.

[0037] In this manner, in this embodiment, at least at the connecting portion 5a, adhesive is disposed on both sides of the optical fiber ribbon 1 to bond the optical fiber strands together, so that it is possible to obtain adhesive strength that is approximately the same as that in the case where adhesive portions are formed continuously on both the top and bottom surfaces.

[0038] In addition, since the adhesive is uniformly applied to one side of the optical fiber ribbon 1 and the coating is integrated, the coating can be easily removed all at once during the fusion process compared to when the missing portions 5b are formed on both sides of the optical fiber ribbon 1. In addition, since the adhesive is uniformly applied to one side of the optical fiber ribbon 1, microbending loss is less likely to occur, and it is possible to suppress an increase in loss.

[0039] In the above-described embodiment, an example in which all the adhesive portions 5 are arranged intermittently in the longitudinal direction is shown, but this is not limited to this. Fig. 3(a) is a top perspective view showing the optical fiber ribbon 1a, and Fig. 3(b) is a bottom perspective view showing the optical fiber ribbon 1a.

[0040] The optical fiber ribbon 1a has a configuration substantially similar to that of the optical fiber ribbon 1, but is different in the number of optical fiber strands and the shape of the bonding parts 5. In the optical fiber ribbon 1a, not all of the bonding parts 5 are arranged intermittently in the longitudinal direction, but some of the bonding parts 5 are arranged continuously in the longitudinal direction.

[0041] For example, in the illustrated example, eight optical fiber strands 3a to 3h are connected, but the adhesive parts 5 between the optical fiber strands 3a and 3b, between the optical fiber strands 3c and 3d, between the optical fiber strands 3e and 3f, and between the optical fiber strands 3g and 3h are not arranged intermittently but are formed continuously in the longitudinal direction. Also, the adhesive parts 5 between the optical fiber strands 3b and 3c, between the optical fiber strands 3d and 3e, and between the optical fiber strands 3f and 3g are arranged intermittently in the longitudinal direction, similar to the optical fiber ribbon 1 described above.

[0042] Even in this case, the connecting portions 5a and the missing portions 5b on the lower surface side are formed at positions corresponding to the adhesive portions 5 on the upper surface side. That is, the arrangement of the adhesive portions 5 is the same on the upper and lower surfaces. Therefore, between the optical fiber strands corresponding to the adhesive portions 5 formed continuously over the entire longitudinal length on the upper surface side, the connecting portions 5a and the missing portions 5b are also formed over the entire longitudinal length on the lower surface. Moreover, between the optical fiber strands corresponding to the adhesive portions 5 arranged intermittently in the longitudinal direction on the upper surface side, the connecting portions 5a and the missing portions 5b (i.e., the adhesive portions 5) are also similarly formed intermittently in the longitudinal direction on the lower surface.

[0043] In this manner, the present invention relates to an optical fiber ribbon in which a plurality of optical fiber strands are arranged in parallel and adjacent optical fiber strands are connected to each other, and as long as at least some of the adjacent optical fiber strands are intermittently bonded to each other at bonding sections 5 formed at predetermined intervals in the longitudinal direction of the optical fiber ribbon, it is not necessary for all of the bonding sections 5 to be arranged intermittently.

[0044] Although the embodiment of the present invention has been described above with reference to the attached drawings, the technical scope of the present invention is not limited to the above-described embodiment. It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0045] 1, 1a: Optical fiber ribbon 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h……Optical fiber wire 5……Adhesive part 5a……Connection part 5b………Defective part

Claims

1. An optical fiber ribbon having a plurality of optical fiber strands arranged in parallel, At least some of the adjacent optical fibers are intermittently bonded to each other at bonding sections formed at predetermined intervals in the longitudinal direction of the optical fiber ribbon, the adhesive portions on one side and the other side of the optical fiber ribbon are provided at substantially the same positions in the longitudinal direction of the optical fiber ribbon, An optical fiber ribbon core wire characterized in that the adhesive portion on one side of the optical fiber ribbon core wire is formed by continuously bonding adjacent optical fiber strands, and the adhesive portion on the other side of the optical fiber ribbon core wire has a missing portion formed in part, and a portion where the connection portion is not continuous.

2. 2. The optical fiber ribbon according to claim 1, wherein the length of the missing portion is 0.2 mm or more and 3 mm or less.

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