JP5910044B2 - Optical fiber and optical fiber manufacturing method - Google Patents

Description

  The present invention has a primary resin layer formed on the outer periphery of the glass fiber, a secondary resin layer formed on the outer periphery of the primary resin layer, and a colored layer formed on the outer periphery of the secondary resin layer, and the secondary resin layer The present invention relates to an optical fiber in which an identification mark for identifying an optical fiber is formed between a colored layer and a colored layer, and a method for manufacturing the same.

  Conventionally known is an optical fiber having a structure in which a soft primary resin layer having a relatively low Young's modulus is provided on the outside of a glass fiber and a hard secondary resin layer having a high Young's modulus is provided on the outside thereof. In such an optical fiber, if a minute foreign substance exists on the line when drawing or rewinding the optical fiber, an external force is locally applied, and peeling may occur at the interface between the optical fiber and the primary resin layer. is there.

  In order to solve such a problem, for example, Patent Document 1 discloses an optical fiber in which the Young's modulus of the primary resin layer is 0.1 MPa or less and the ratio of the Young's modulus of the secondary resin layer to the primary resin layer is 10,000 or more. It is disclosed.

  Conventionally, the optical fiber in the optical fiber cable has been identified by the color of the colored layer of the optical fiber. However, in order to identify more optical fibers as the number of optical fiber cables increases, the type of optical fiber is changed. In general, an identification mark for identification is attached to an optical fiber. For example, in Patent Document 2, an identification layer (identification mark) that enables an optical fiber to be identified by ejecting ink by an ink jet printer is formed on an optical fiber, and transparent or translucent is formed thereon. An optical fiber cable having a colored layer is disclosed.

JP 2001-108874 A Japanese Patent Laid-Open No. 2004-77536

  However, in the techniques of Patent Documents 1 and 2 described above, when an ink droplet is sprayed by an ink jet method and an identification mark for identifying an optical fiber is formed on an optical fiber, the Young's modulus of the primary resin layer and the secondary resin layer is light. No consideration was given to the effect on fiber transmission loss.

  In the manufacture of an optical fiber with a normal identification mark, after the identification mark is formed, the identification mark is further coated with an ultraviolet curable resin that becomes a transparent or translucent colored layer, and ultraviolet irradiation is performed. When the ultraviolet curable resin is cured by the irradiation of ultraviolet rays, the identification mark may press the secondary resin layer, the primary resin layer, and the glass fiber, and transmission loss due to microbending may occur. The magnitude of this transmission loss is related to the Young's modulus of the primary resin layer and the secondary resin layer.

  The present invention has been made in view of the above-described circumstances, and effectively suppresses transmission loss due to microbending in consideration of the Young's modulus of the primary resin layer and the secondary resin layer when forming the identification mark. An object of the present invention is to provide an optical fiber that can be used and a method of manufacturing the optical fiber.

The optical fiber according to the present invention has a primary resin layer formed on the outer periphery of the glass fiber, a secondary resin layer formed on the outer periphery of the primary resin layer, and a colored layer formed on the outer periphery of the secondary resin layer. This optical fiber has an identification mark for identification formed by spraying ink droplets by an ink jet method between the secondary resin layer and the colored layer. The Young's modulus of the primary resin layer is 0.4 MPa to 1.0 MPa, and the Young's modulus of the secondary resin layer is 800 MPa to 1800 MPa. The identification marks are formed in contact with each other, h is the minimum height of the recessed portion of the identification mark from the outer peripheral surface of the secondary resin layer, and H is the maximum height of the identification mark from the outer peripheral surface of the secondary resin layer. In this case, the ratio H / h is set to 2.5 or less.

Also, in a cross section perpendicular to the longitudinal direction of the optical fiber, the central angle of the part identification mark is formed may be 180 degrees or more. Furthermore, the number per unit length in the longitudinal direction of the identification mark formed on the outer peripheral surface of the secondary resin layer may be 2 / mm or more and 4 / mm or less.

Moreover, in the manufacturing method of the optical fiber by this invention, a primary resin layer is formed in the outer periphery of a glass fiber, a secondary resin layer is formed in the outer periphery of a primary resin layer, and a colored layer is further formed in the outer periphery of a secondary resin layer. Then, the Young's modulus of the primary resin layer is set to 0.4 MPa to 1.0 MPa, and the Young's modulus of the secondary resin layer is set to 800 MPa to 1800 MPa. Further, ink droplets are sprayed on the outer peripheral surface of the secondary resin layer by an ink jet method to form an identification mark for identification between the secondary resin layer and the colored layer. The identification marks are formed in contact with each other, h is the minimum height of the recessed portion of the identification mark from the outer peripheral surface of the secondary resin layer, and H is the maximum height of the identification mark from the outer peripheral surface of the secondary resin layer. In this case, the ratio H / h is set to 2.5 or less.

  According to the present invention, even when an ink droplet is sprayed onto an optical fiber by an ink jet method to form an identification mark, transmission loss due to microbending can be effectively suppressed.

It is a figure which shows an example of a cross section perpendicular | vertical to the longitudinal direction of the optical fiber which concerns on this invention. It is a figure which shows an example of the longitudinal direction cross section of the optical fiber which concerns on this invention. It is a figure which shows an example of the external appearance of the optical fiber which concerns on this invention. It is a figure which shows the relationship between the increase amount of the transmission loss of an optical fiber, the Young's modulus of a primary resin layer, and the Young's modulus of a secondary resin layer. It is a figure which shows the relationship between the increase amount of the transmission loss of an optical fiber, and the height ratio H / h of an identification mark. It is a figure which shows the relationship between the increase amount of the transmission loss of an optical fiber, and the number N / L of the identification marks per unit. It is a figure which shows the relationship between the increase amount of the transmission loss of an optical fiber, and the center angle of an identification mark. It is a figure which shows an example of the manufacturing apparatus of the optical fiber which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an example of a cross section perpendicular to the longitudinal direction of an optical fiber 10 according to the present invention, and FIG. 2 is a diagram showing an example of a longitudinal section of the optical fiber 10 according to the present invention.

  The optical fiber 10 includes a glass fiber 13, a primary resin layer 14, a secondary resin layer 15, an identification mark 11, and a colored layer 16. A glass fiber 13 whose outer periphery is covered with a primary resin layer 14 and whose outer periphery is covered with a secondary resin layer 15 is also called an optical fiber 17.

  The glass fiber 13 is an optical waveguide having a core part and a clad part, for example, having a standard outer diameter of 125 μm. The glass fiber 13 is made of quartz glass. The primary resin layer 14 is a coating layer made of a soft resin having an outer diameter of about 190 to 200 μm and a relatively low Young's modulus. The secondary resin layer 15 is a coating layer made of a hard resin having an outer diameter of about 240 to 250 μm and a relatively high Young's modulus. The colored layer 16 is a transparent or translucent colored layer made of ultraviolet curable ink and having a thickness of about 5 to 10 μm. Examples of the ultraviolet curable ink used include urethane acrylate.

  Here, the identification mark 11 is formed by spraying ink droplets by an ink jet method as described above. At that time, since the ink droplet has surface tension, the portion to which the ink droplet is sprayed does not become flat, and the shape of the identification mark 11 is crater-like (on the concave surface when viewed in cross section) as shown in FIG. It becomes. In FIG. 2, the maximum height of the identification mark 11 from the secondary resin layer 15 is represented by H, and the minimum height of the depression of the identification mark 11 is represented by h. As shown in FIG. 1, the identification mark 11 covers a certain range of the outer periphery of the secondary resin layer 15. In FIG. 1, the central angle of the identification mark 11 covering the certain range is represented by θ.

  Moreover, FIG. 3 is a figure which shows an example of the external appearance of the optical fiber 10 which concerns on this invention. As shown in FIG. 3, a plurality of identification marks 11 indicating the type of optical fiber are continuously formed on the optical fiber 10 by spraying ink droplets by an ink jet method (seven in the example of FIG. 3). An identification mark 12 is formed. Further, the continuous identification mark 12 is repeatedly formed with a predetermined interval.

  When the colored layer 16 as shown in FIGS. 1 and 2 is irradiated with ultraviolet rays and the colored layer 16 is cured, the identification mark 11 is pressed against the secondary resin layer 15, and the secondary resin layer 15 becomes the primary resin layer 14. The primary resin layer 14 is further pressed against the glass fiber 13. As a result, a lateral pressure is applied to the glass fiber 13, and microbending may occur in the glass fiber 13. In order to suppress this, in the present invention, the Young's modulus of the primary resin layer 14 and the secondary resin layer 15, the shape of the identification mark 11, the configuration of the continuous identification mark 12, and the like are adjusted.

  FIG. 4 is a diagram illustrating the relationship between the increase in transmission loss of the optical fiber 10 and the Young's modulus of the primary resin layer 14 and the Young's modulus of the secondary resin layer 15. FIG. 5 is a diagram showing the relationship between the increase in transmission loss of the optical fiber 10 and the height ratio H / h of the identification mark 11. FIG. 6 is a diagram illustrating a relationship between an increase in transmission loss of the optical fiber 10 and the number N / L of identification marks 11 per unit. FIG. 7 is a diagram illustrating the relationship between the increase in transmission loss of the optical fiber 10 and the center angle θ of the identification mark 11. 4 to 7, the linear velocity at the time of manufacturing the optical fiber is 800 m / min, and the length of the continuous identification mark is 2 mm.

  Here, the amount of increase in the transmission loss of the optical fiber 10 is the transmission loss of the optical fiber 10 when the identification mark 11 is formed compared to the transmission loss of the optical fiber when the identification mark 11 is not formed. It is an amount that indicates whether it has increased. However, here, the amount of increase when the transmission loss is measured using light having a wavelength of 1550 nm is shown.

  As shown in FIG. 4, when the Young's modulus of the primary resin layer 14 is 0.4 MPa or more and 1.0 MPa or less, and the Young's modulus of the secondary resin layer 15 is 800 MPa or more and 1800 MPa or less, the increase in transmission loss is 0. Less than 0.01 dB / km (samples S1 to S7 indicated by “◎” in FIG. 4).

  On the other hand, in an area other than the above range, the increase in transmission loss is an order of magnitude greater than 0.01 dB / km (samples S8 to S11 indicated by “x” in FIG. 4). Sample S24 (sample S24 indicated by “Δ” in FIG. 4) has a transmission loss of less than 0.01 dB / km, but poor adhesion between the glass fiber 13 and the primary resin layer 14 occurred. . In addition, although the sample S25 (sample S25 indicated by “Δ” in FIG. 4) has a transmission loss of less than 0.01 dB / km, a phenomenon in which the colored layer 16 is peeled off from the secondary resin layer 14 was observed.

  Further, as shown in FIGS. 5, 6, and 7, when the height ratio H / h of the identification mark 11 exceeds 2.5, the number N / L of the identification marks 11 per unit is 4 / When the distance exceeds mm, when the center angle of the identification mark 11 is less than 180 degrees, the increase in transmission loss exceeds 0.01 dB / km, which increases rapidly. 5, 6, and 7, the same optical fiber 17 is used and the optical fiber 10 is manufactured by changing the conditions of the identification mark. Therefore, the primary resin layer 14 and the secondary resin layer are used. The Young's modulus of 15 is almost the same value in each figure.

As described above, the amount of increase in transmission loss increases according to each condition because the degree of unevenness increases as the height ratio of the identification mark increases, and the influence of unevenness increases as the density of the identification mark increases. This is because the smaller the central angle, the more likely it is that the local force is applied, and the greater the transmission loss due to microbending. In addition, the identification marks are preferably formed in contact with each other, rather than discretely, from the viewpoint of transmission loss for the same reason as described above. The transmission loss is reduced by increasing.
In FIG. 6, when the number N / L of identification marks 11 per unit length is less than 2 / mm, an increase in transmission loss hardly occurs, but it is difficult to visually recognize the identification marks 11. The number N / L of identification marks 11 per unit needs to be 2 pieces / mm or more.

  As described above, if the Young's modulus of the primary resin layer 14 is set to 0.4 MPa or more and 1.0 MPa or less and the Young's modulus of the secondary resin layer 15 is set to 800 MPa or more and 1800 MPa or less, generation of transmission loss can be effectively suppressed. Furthermore, the height ratio H / h of the identification mark 11 is set to 2.5 or less, the number N / L of the identification marks 11 per unit is set to 2 / mm or more and 4 / mm or less, and the identification mark 11 If the central angle is 180 degrees or more, the generation of transmission loss can be more effectively suppressed.

  Below, an example of the manufacturing apparatus 20 of the optical fiber 10 which concerns on embodiment of this invention is demonstrated. FIG. 8 is a diagram illustrating an example of the manufacturing apparatus 20 for the optical fiber 10 according to the embodiment of the present invention. As shown in FIG. 8, the manufacturing apparatus 20 includes a supply bobbin 21, a roller 22, an ink jet head 23, a colored layer forming device 24, ultraviolet irradiation devices 25a and 25b, a control device 26, a capstan 27, and a winding bobbin 28. Prepare.

  The supply bobbin 21 is a bobbin that supplies the optical fiber 17 before the identification mark 11 is added to the manufacturing apparatus 20. The optical fiber strand 17 is fed out through the roller 22, and an ink droplet is sprayed onto the secondary resin layer 15 of the optical fiber strand 17 by the inkjet head 23 to form the identification mark 11.

  The colored layer forming device 24 is a device that forms the colored layer 16 from above the identification mark 11. The colored layer forming apparatus 24 forms the colored layer 16 by applying ultraviolet curable ink from above the identification mark 11. The ultraviolet irradiation devices 25 a and 25 b are devices that cure the colored layer 16 by irradiating the colored layer 16 with ultraviolet rays. The control device 26 is a device for controlling the ultraviolet irradiation amount of the ultraviolet irradiation devices 25a and 25b.

  Thereafter, the optical fiber 10 is pulled by the capstan 27 via the roller 22. The winding bobbin 28 winds the optical fiber 10 taken up by the capstan 27 after the colored layer 15 is cured.

DESCRIPTION OF SYMBOLS 10 ... Optical fiber, 11 ... Identification mark, 12 ... Continuous identification mark, 13 ... Glass fiber, 14 ... Primary resin layer, 15 ... Secondary resin layer, 16 ... Colored layer, 17 ... Optical fiber strand, 20 ... Manufacturing apparatus, DESCRIPTION OF SYMBOLS 21 ... Supply bobbin, 22 ... Roller, 23 ... Inkjet head, 24 ... Colored layer formation apparatus, 25a, 25b ... Ultraviolet irradiation apparatus, 26 ... Control apparatus, 27 ... Capstan, 28 ... Winding bobbin.

Claims (4)

An optical fiber having a primary resin layer formed on the outer periphery of the glass fiber, a secondary resin layer formed on the outer periphery of the primary resin layer, and a colored layer formed on the outer periphery of the secondary resin layer,
An identification mark for identification formed by spraying ink droplets by an ink jet method is provided between the secondary resin layer and the colored layer, and the Young's modulus of the primary resin layer is 0.4 MPa or more and 1.0 MPa or less. , a Young's modulus of the secondary resin layer Ri 1800MPa der less than 800 MPa,
The identification marks are formed in contact with each other, and h is the minimum height of the recessed portion of the identification mark from the outer peripheral surface of the secondary resin layer, and the maximum height of the identification mark from the outer peripheral surface of the secondary resin layer An optical fiber characterized in that the ratio H / h when H is H is 2.5 or less . 2. The optical fiber according to claim 1 , wherein a central angle of a portion where the identification mark is formed is 180 degrees or more in a cross section perpendicular to the longitudinal direction of the optical fiber. The number per unit length in the longitudinal direction of the identification mark formed on the outer peripheral surface of the secondary resin layer is 2 pieces / mm or more and 4 pieces / mm or less or more. Optical fiber.   A primary resin layer is formed on the outer periphery of the glass fiber, a secondary resin layer is formed on the outer periphery of the primary resin layer, and a colored layer is further formed on the outer periphery of the secondary resin layer,
  The primary resin layer has a Young's modulus of 0.4 MPa to 1.0 MPa and the secondary resin layer has a Young's modulus of 800 MPa to 1800 MPa. Forming an identification mark for identification between the resin layer and the colored layer;
  The identification marks are formed in contact with each other, and h is the minimum height of the recessed portion of the identification mark from the outer peripheral surface of the secondary resin layer, and the maximum height of the identification mark from the outer peripheral surface of the secondary resin layer A method of manufacturing an optical fiber, wherein the ratio H / h when H is H is 2.5 or less.

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