Optical fiber embedded sheet, optical fiber installation method, and attachment device

Abstract

To provide an optical fiber embedded sheet that has sufficient temporary fixing properties until attachment to an installation target is completed.SOLUTION: The present invention is an optical fiber embedded sheet having an optical fiber used as a sensor embedded therein. A substrate 11, an adhesive layer 12, and a viscous adhesive layer 13 are laminated in this order. At least part of the optical fiber 14 is embedded in the viscous adhesive layer. The adhesive layer has a larger width than the viscous adhesive layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical fiber embedded sheet having optical fibers embedded therein, an optical fiber installation method, and an optical fiber embedded sheet attachment device used therefor. [Background technology]

[0002] Optical fibers have the characteristic that they can measure strain and temperature distributions over their entire length by analyzing scattered light observed when pulsed laser light is incident on them.

[0003] Taking advantage of this property, optical fiber sensors are currently being put to practical use for detecting deformation and measuring temperature in structures. For example, Patent Document 1 describes an example in which a sensor with an optical fiber fixed between sheets is attached to the surface of concrete with an adhesive to detect deformation (damage) in a concrete structure from the strain of the optical fiber. Furthermore, Patent Document 2 describes an example in which an optical fiber sensor with an optical fiber fixed to an installation member is bonded to the structure with a bonding material provided on the installation member, and deformation of the structure is detected from the strain of the optical fiber.

[0004] In Patent Document 1, the optical fiber is fixed between sheets, and in Patent Document 2, the optical fiber is fixed to a sheet-like installation member, and the sheet or installation member is attached to the installation target, thereby reducing the labor required for installation. However, this requires costs to manufacture the sensor, and because the sheet or installation member is interposed between the installation target and the optical fiber, deformation of the installation target may not be easily reflected in the sensor's measurement results.

[0005] Therefore, Patent Document 3 discloses an optical fiber embedded sheet incorporating optical fibers used as sensors. The optical fibers are embedded in an adhesive layer, and no sheet or other material is interposed between the optical fibers and the installation target, so deformation of the installation target is easily reflected in the measurement results of the optical fibers, and the layer structure is simple and low cost. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-131025 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-48516 [Patent Document 3] Patent Publication No. 2021-148713 Summary of the Invention [Problem to be solved by the invention]

[0007] However, it has been found that conventional optical fiber embedded sheets have room for further improvement in terms of their temporary fixation to the installation target. In the optical fiber embedded sheet described in Patent Document 3, the adhesive layer has tackiness, which allows the sheet to be temporarily fixed to the installation target, and the sheet is then fixed to the installation target by hardening the adhesive layer. However, when attaching the sheet to, for example, a ceiling, the tackiness of the adhesive layer alone is insufficient for temporary fixation, and there is a risk that the sheet will peel off before the adhesive layer has completely hardened.

[0008] Therefore, an object of the present invention is to provide an optical fiber embedded sheet or the like that has sufficient temporary fixation until attachment to an installation target is completed. [Means for solving the problem]

[0009] In order to solve the above problems and achieve the object, the present invention has the following configuration.

[0010] [1] An optical fiber embedded sheet incorporating an optical fiber used as a sensor, a substrate, a pressure-sensitive adhesive layer, and a pressure-sensitive adhesive layer are laminated in this order; At least a portion of the optical fiber is embedded in the adhesive layer, The pressure-sensitive adhesive layer is wider than the pressure-sensitive adhesive layer. Optical fiber embedded sheet. [2] The optical fiber embedded sheet according to [1], wherein, when the width (cm) of the pressure-sensitive adhesive layer is X and the width (cm) of the adhesive layer is Y, 0.05≦Y / X≦0.95. [3] The optical fiber embedded sheet according to [1] or [2], wherein the adhesive layer is provided with a wire for tearing the sheet. [4] A method for installing an optical fiber, comprising adhering the optical fiber embedded sheet according to any one of [1] to [3] to an installation target using the pressure-sensitive adhesive layer and the adhesive layer, and then bonding the sheet to the installation target using the cured adhesive layer. [5] The optical fiber installation method according to [4], wherein a primer that hardens the adhesive layer by chemical reaction with the adhesive layer is applied to the installation target, and then the optical fiber embedded sheet is attached to the installation target at the application position of the primer. [6] [4] The optical fiber installation method according to [4], wherein a primer that hardens the adhesive layer by chemical reaction with the adhesive layer is applied to the adhesive layer, and then the adhesive layer is brought into contact with the installation target, and the optical fiber embedded sheet is attached. [7] Using a bonding device having a reel around which the optical fiber embedded sheet is wound and a pressure roller, The optical fiber installation method according to any one of [4] to [6], wherein the optical fiber embedded sheet is attached by moving the attachment device in the attachment direction of the optical fiber embedded sheet while pressing the optical fiber embedded sheet unwound from the reel toward the installation target side with the pressure roller. [8] An attachment device for attaching the optical fiber embedded sheet according to any one of [1] to [3] to an installation target, a reel around which the optical fiber embedded sheet is wound; a presser roller for pressing the optical fiber embedded sheet unwound from the reel toward the installation target; An application device having the above structure. [Effects of the Invention]

[0011] The optical fiber embedded sheet of the present invention has a pressure-sensitive adhesive layer and a pressure-sensitive adhesive layer that is wider than the pressure-sensitive adhesive layer, so it can provide sufficient temporary fixation to the installation target. Therefore, peeling of the sheet can be suppressed until the pressure-sensitive adhesive layer is completely cured. Furthermore, it reduces the labor required for installing the optical fiber and enables suitable sensing at low cost. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a first optical fiber incorporated sheet according to one embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing a second optical fiber incorporated sheet according to another embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing a third optical fiber incorporated sheet according to another embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing a method for applying a primer 9 to an optical fiber installation target 3. In FIG. [Figure 5] FIG. 5 is a diagram showing a method for installing the optical fiber 14. As shown in FIG. [Figure 6] FIG. 6 is a diagram showing the adhering device 5a. [Figure 7] FIG. 7 is a cross-sectional view showing the vicinity of the cracked portion 3a of the installation target 3. As shown in FIG. [Figure 8] FIG. 8 is a diagram showing the optical fiber embedded sheet 1a. [Figure 9] FIG. 9 is a diagram showing an optical fiber embedded sheet 1c. [Figure 10] FIG. 10 shows optical fiber embedded sheets 1d and 1e. [Figure 11] FIG. 11 is a diagram showing the results of measuring adhesive strength in the examples. [Figure 12] FIG. 12 is a diagram showing the results of measuring the tape feeding force in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0013] In this specification, the term "A to B" indicating a range means "greater than or equal to A and less than or equal to B." Furthermore, in this specification, "weight" and "mass," "wt %" and "mass %" are treated as synonyms.

[0014] In addition, in this specification, the term "adhesive" refers to a material that exhibits peel resistance without solidifying. Specifically, an adhesive is also called a pressure-sensitive adhesive, and refers to a material that is in a soft solid (viscoelastic) state in a temperature range around room temperature and has the property of easily adhering to an adherend by pressure. The adhesive referred to here is generally a material having a complex tensile modulus E as defined in "C A Ahlquist, "Adhesion: Fundamentals and Practice", McLaren & Sons, (1966) p. 143". * (1Hz)<10 7 dyne / cm 2 The adhesive layer may be a material having properties that satisfy the above (typically, a material having the above properties at 25°C). Furthermore, the term "adhesive layer" refers to a layer formed from an adhesive. Furthermore, "adhesiveness" refers to the above properties possessed by an adhesive.

[0015] In this specification, the term "adhesive" refers to a material that has the above-mentioned pressure-sensitive adhesive function and increases peel resistance upon curing, and the term "adhesive layer" refers to a layer formed from an adhesive.

[0016] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described below. Furthermore, in the following drawings, components and parts that perform the same function may be described using the same reference numerals, and duplicated descriptions may be omitted or simplified. Furthermore, the embodiments shown in the drawings are schematic in order to clearly explain the present invention, and do not necessarily accurately represent the size or scale of an actual product.

[0017] (1. Optical fiber embedded sheet) An optical fiber embedded sheet according to an embodiment of the present invention is an optical fiber embedded sheet incorporating an optical fiber to be used as a sensor, characterized in that a base material, an adhesive layer, and a tacky adhesive layer are laminated in this order, at least a portion of the optical fiber is embedded in the tacky adhesive layer, and the adhesive layer is wider than the tacky adhesive layer.

[0018] In one embodiment of the present invention, the optical fiber embedded sheet is adhered to an optical fiber installation target by bringing the adhesive layer into contact with the target, and then the adhesive layer gradually hardens, thereby fixing the sheet to the target. As shown in FIG. 1( a), the adhesive layer 12 of the sheet is wider than the adhesive layer 13. Therefore, when the sheet is attached to the target via the adhesive layer 13, the adhesive layer 12 conforms to the step formed between the surface of the target and the adhesive layer 13, and adheres to the target where the optical fiber 14 is to be installed. In this way, the adhesive layer 12 of the sheet adheres to the target where the optical fiber 14 is to be installed, in addition to the adhesive layer 13, and therefore the adhesive layer 12 also adheres to the target where the optical fiber 14 is to be installed, thereby achieving sufficient temporary fixation and preventing the sheet from peeling off before the adhesive layer 13 has completely hardened. Here, "temporary fixation" means that the optical fiber embedded sheet is temporarily fixed to the installation target of the optical fiber 14 by the adhesive properties of the adhesive layer 12 and the adhesive layer 13 until the hardening of the adhesive layer 13 is completed.

[0019] Furthermore, by adhering the optical fiber embedded sheet of one embodiment of the present invention to the target for optical fiber installation using its adhesive layer and pressure-sensitive adhesive layer, and then bonding it using the adhesive layer, sufficient temporary fixation can be achieved, thereby reducing the labor required for optical fiber installation work.

[0020] Furthermore, the substrate, pressure-sensitive adhesive layer, and adhesive layer of the optical fiber embedded sheet function as protective layers for the optical fiber, reducing the risk of damage to the optical fiber due to external contact.

[0021] Furthermore, at least a portion of the optical fiber is embedded in the above-mentioned adhesive layer, and deformation of the installation object, etc. is easily reflected in the measurement results of the optical fiber through the hardened adhesive layer, and the layer structure is simple and low-cost.

[0022] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0023] (1.1. First Optical Fiber Embedded Sheet) 1 is a diagram showing a first optical fiber embedded sheet according to one embodiment of the present invention. The first optical fiber embedded sheet is a strip-shaped sheet material incorporating optical fibers 14 used as sensors, and detects deformation of an object to which the optical fibers 14 are attached by detecting strain in the optical fibers 14.

[0024] Fig. 1(a) is a cross-sectional view perpendicular to the longitudinal direction of the first optical fiber embedded sheet, and Fig. 1(b) is a top view of the first optical fiber embedded sheet of Fig. 1(a). As shown in Fig. 1(a), the first optical fiber embedded sheet has a laminated structure of a substrate 11, a pressure-sensitive adhesive layer 12, and a tacky adhesive layer 13, and at least a portion of an optical fiber 14 is embedded in the tacky adhesive layer 13. By embedding at least a portion of the optical fiber 14 in the tacky adhesive layer 13, no sheet or the like is interposed between the optical fiber and the installation object, and therefore deformation of the installation object and the like are more likely to be reflected in the measurement results of the optical fiber.

[0025] (base material) The material of the substrate 11 is not particularly limited, and can be a resin film or the like, and can be appropriately selected depending on the use mode of the optical fiber embedded sheet, etc. Examples of resin materials that can be used to form the resin film include polyester, polyolefin, polycycloolefin derived from a monomer having an alicyclic structure such as a norbornene structure, polyamide (PA) such as nylon 6, nylon 66, and partially aromatic polyamide, polyimide (PI), polyamide-imide (PAI), polyether ether ketone (PEEK), polyether sulfone (PES), polyphenylene sulfide (PPS), polycarbonate (PC), polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), polystyrene, fluororesins such as polyvinyl chloride, polyvinylidene chloride, and polytetrafluoroethylene (PTFE), acrylic resins such as polymethyl methacrylate, cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose, vinyl butyral-based polymers, arylate-based polymers, polyoxymethylene-based polymers, and epoxy-based polymers. The resin film may be formed using a resin material containing one of these resins alone, or may be formed using a resin material in which two or more of these resins are blended. The resin film may be unstretched or stretched (for example, uniaxially or biaxially stretched).

[0026] When the optical fiber embedded sheet is used outdoors or in other environments exposed to sunlight, deterioration of the optical fiber embedded sheet due to sunlight can be prevented by using a material with known ultraviolet resistance for the base material 11. Furthermore, when the optical fiber embedded sheet is used in an environment where it will come into contact with concrete, such as inside concrete, deterioration of the optical fiber embedded sheet due to the alkaline components of the concrete can be prevented by using a material with known alkali resistance for the base material 11.

[0027] The thickness of the substrate 11 is not particularly limited and can be selected depending on the usage mode of the optical fiber embedded sheet, etc. The thickness of the substrate 11 may be, for example, 1000 μm or less, 500 μm or less, 100 μm or less, 70 μm or less, 50 μm or less, 25 μm or less, 10 μm or less, or 5 μm or less. As the thickness of the substrate decreases, the flexibility of the optical fiber embedded sheet and its ability to conform to the surface shape of the installation target tend to improve. Furthermore, from the viewpoint of handleability and processability, the thickness of the substrate 11 may be, for example, 2 μm or more, 5 μm or more, 10 μm or more, 20 μm or more, 35 μm or more, or 55 μm or more.

[0028] (Adhesive layer) The adhesive layer 12 is a layer that is mainly used to temporarily fix the optical fiber embedded sheet to an installation target. The adhesive layer 12 may be provided on one side of the substrate 11 across the entire width of the substrate 11, or it may not be provided across the entire width. The adhesive layer 12 is wider than the adhesive layer 13 described below. Because the adhesive layer 12 is wider than the adhesive layer 13, when the sheet is attached to an installation target via the adhesive layer 13, the adhesive layer 12 conforms to the step formed between the installation target surface and the adhesive layer 13, and is adhered to the installation target of the optical fiber 14. The adhesive layer 12 adheres to the installation target of the optical fiber 14 together with the adhesive layer 13, thereby increasing the adhesive strength of the sheet, achieving sufficient temporary fixation, and preventing the sheet from peeling off until the adhesive layer 13 has completely hardened.

[0029] The "width" mentioned above refers to the length in the direction perpendicular to the longitudinal direction of the optical fiber embedded sheet on a plane, and corresponds to the length in the left-right direction in FIG. 1(a).

[0030] 1(a), when the width (cm) of the pressure-sensitive adhesive layer 12 is X and the width (cm) of the pressure-sensitive adhesive layer 13 described later is Y, Y / X is preferably 0.95 or less, more preferably 0.9 or less, and even more preferably 0.8 or less. When Y / X is in the above range, sufficient temporary fixation by the pressure-sensitive adhesive layer 12 can be obtained. Furthermore, Y / X is preferably 0.05 or more, more preferably 0.1 or more, and even more preferably 0.3 or more. By keeping Y / X within the above range, an increase in the sheet feeding force is suppressed, workability is improved, and excessive stress on the optical fiber can be suppressed.

[0031] The width (cm) X of the adhesive layer 12 is preferably 1 cm or more, more preferably 1.5 cm or more, and is preferably 5 cm or less, more preferably 3 cm or less. When the width X of the adhesive layer 12 is 1 cm or more, the adhesion area increases and the adhesive strength improves, which is advantageous in terms of the adhesiveness of the optical fiber embedded sheet. When the width X of the adhesive layer 12 is 5 cm or less, it is possible to avoid an increase in weight when the optical fiber embedded sheet is rolled up and a deterioration in manual adhesion, which is advantageous in terms of handleability.

[0032] Known adhesives can be used for the adhesive layer 12, and examples thereof include adhesives containing base polymers such as acrylic polymers, rubber polymers, vinyl alkyl ether polymers, silicone polymers, polyester polymers, polyamide polymers, urethane polymers, fluorine-based polymers, and epoxy polymers. Among these, adhesives containing acrylic polymers (acrylic adhesives) are preferred in terms of adhesive strength and weather resistance. Note that such polymers may be used alone or in combination of two or more.

[0033] Furthermore, when the optical fiber 14 is to be installed in a concrete member, the adhesive layer 12 can be made of a material known to be alkali-resistant, thereby preventing deterioration of the optical fiber embedded sheet due to the alkali components of the concrete.

[0034] The thickness of the pressure-sensitive adhesive layer 12 is, for example, 200 μm or more, preferably 400 μm or more, more preferably 600 μm or more, and for example, 1400 μm or less, preferably 1200 μm or less, more preferably 1000 μm or less. Having a thickness of 200 μm or more for the pressure-sensitive adhesive layer 12 is advantageous in that the optical fiber is embedded in the pressure-sensitive adhesive layer, reducing external pressure and providing adequate protection for the optical fiber. Having a thickness of 1400 μm or less for the pressure-sensitive adhesive layer 12 is advantageous in that it avoids weight gain and poor manual application when the optical fiber embedded sheet is rolled, thereby improving handleability.

[0035] (Adhesive layer) The adhesive layer 13 is a layer that mainly adheres and fixes the optical fiber embedded sheet to an installation target. Known adhesives can be used for the adhesive layer 13, and among them, it is preferable to use a material that hardens by chemical reaction with a primer, which will be described later, for the adhesive layer 13. For example, it can be the main component of a two-component adhesive that contains an epoxy resin as the main component and can form a layer. Components that can be contained other than the epoxy resin include, for example, silicone compounds, polyol compounds such as polypropylene glycol, and urethane resins. By containing an epoxy resin as the main component, the adhesive can firmly adhere to an installation target. Here, the term "main component" refers to the component that is contained in the largest amount by mass in the composition or layer.

[0036] Examples of epoxy resins include bisphenol-based epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, and hydrogenated bisphenol A-type epoxy resins; naphthalene-type epoxy resins, biphenyl-type epoxy resins, dicyclo-type epoxy resins, alicyclic-type epoxy resins, triglycidyl isocyanurate epoxy resins, hydantoin epoxy resins, glycidyl ether-type epoxy resins, and glycidylamino-type epoxy resins. Furthermore, polyfunctional epoxy resins having three or more functionalities can also be used as the epoxy resin, such as phenol novolac epoxy resins, orthocresol novolac epoxy resins, triphenyl novolac epoxy resins, bisphenol A novolac epoxy resins, and aliphatic epoxy resins.

[0037] The epoxy resin is preferably a bisphenol-based epoxy resin, more preferably a bisphenol A-type epoxy resin. The epoxy resins can be used alone or in combination of two or more kinds. When a polyfunctional epoxy resin is used, its content is preferably 1 to 50 mass %, more preferably 3 to 30 mass %, based on the total amount of the epoxy resin.

[0038] The epoxy resin may be in any of a liquid, semi-solid and solid form at room temperature, but preferably, a semi-solid epoxy resin is used alone, or a liquid epoxy resin and a solid epoxy resin are used in combination, which allows a tacky adhesive layer to be reliably formed from the adhesive composition.

[0039] Specifically, an epoxy resin that is liquid at room temperature is liquid at 25° C. The viscosity of the liquid epoxy resin at 25° C. is, for example, 30 Pa·s or more, or preferably 80 Pa·s or more, and for example, 500 Pa·s or less, or preferably 300 Pa·s or less.

[0040] Specifically, an epoxy resin that is solid at room temperature is solid at 25° C. The softening point of the solid epoxy resin is, for example, 70° C. or higher, preferably 75° C. or higher.

[0041] When a liquid epoxy resin and a solid epoxy resin are used in combination, the blending ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin / solid epoxy resin) is, for example, 1.0 or more, preferably 1.5 or more, and for example, 4.0 or less, preferably 3.0 or less.

[0042] When the blending ratio of the liquid epoxy resin to the solid epoxy resin is equal to or greater than the above lower limit, the viscosity of the adhesive composition can be reduced, the occurrence of unevenness in the coating film can be prevented, and a uniform adhesive layer can be obtained.When the blending ratio of the liquid epoxy resin to the solid epoxy resin is equal to or less than the above upper limit, a tacky adhesive layer can be obtained.

[0043] The content of the epoxy resin in the adhesive layer is preferably 30 to 99 mass %, more preferably 50 to 90 mass %.

[0044] Furthermore, when the optical fiber 14 is to be installed in a concrete member, the adhesive layer 13 can be made of a material known to be alkali-resistant, thereby preventing deterioration of the optical fiber embedded sheet due to the alkali components of the concrete.

[0045] The width (cm) Y of the adhesive layer 13 is preferably 0.2 cm or more, more preferably 0.5 cm or more, and is preferably 3 cm or less, more preferably 2.5 cm or less. When the width (cm) Y of the adhesive layer 13 is 0.2 cm or more, the optical fiber embedded sheet can be sufficiently adhered and fixed to the installation target, and when it is 3 cm or less, it is possible to prevent deterioration of handling due to an increase in the overall width of the optical fiber embedded sheet and to keep the area requiring primer application small.

[0046] The thickness of the adhesive layer 13 is, for example, 3 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and for example, 100 μm or less, preferably 90 μm or less, more preferably 75 μm or less. Having a thickness of 3 μm or more of the adhesive layer 13 is advantageous in that it provides excellent peel strength before curing and excellent impact resistance after curing. Having a thickness of 100 μm or less of the adhesive layer 13 is also advantageous in that a primer, which will be described below, can easily penetrate into the adhesive layer 13, thereby improving the curing rate.

[0047] (optical fiber) The optical fiber 14 is a linear member made of glass or the like. A known fiber member for sensors can be used for the optical fiber 14. The optical fiber 14 is arranged so that its longitudinal direction is aligned with the longitudinal direction of the optical fiber embedded sheet, and at least a portion of the optical fiber 14 is embedded in the adhesive layer. Also, at least a portion of the optical fiber 14 may be embedded in the adhesive layer.

[0048] (Release liner) In the optical fiber incorporated sheet of this embodiment, the pressure-sensitive adhesive layer 12 and the pressure-sensitive adhesive layer 13 may be protected by a release liner (separator, release film) until use.

[0049] As the release liner, a conventional release paper or the like can be used, and is not particularly limited. For example, a substrate having a release treatment layer, a low-adhesion substrate made of a fluorine-based polymer, or a low-adhesion substrate made of a non-polar polymer can be used. Examples of substrates having a release treatment layer include plastic films and papers that have been surface-treated with a release agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide-based release agent. Examples of fluoropolymers for low-adhesion substrates made of fluoropolymers include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, and chlorofluoroethylene-vinylidene fluoride copolymer. Examples of the non-polar polymer in the low-adhesion substrate made of a non-polar polymer include olefin resins (e.g., polyethylene, polypropylene, etc.). The release liner can be formed by a known or conventional method. There are also no particular limitations on the thickness of the release liner.

[0050] (1.2. Second optical fiber embedded sheet) Fig. 2 is a diagram showing a second optical fiber embedded sheet according to another embodiment of the present invention. The second optical fiber embedded sheet is a strip-shaped sheet material incorporating multiple optical fibers 24 (first optical fiber 24a, second optical fiber 24b) used as sensors. Note that, although Fig. 2 shows two optical fibers 24 incorporated in the sheet, the number is not limited to this and may be three or more. Furthermore, unless otherwise specified, the explanations given for the first embodiment of the optical fiber embedded sheet described above apply to each configuration of the second optical fiber embedded sheet of this embodiment.

[0051] Fig. 2(a) is a cross-sectional view perpendicular to the longitudinal direction of the second optical fiber embedded sheet, and Fig. 2(b) is a top view of the second optical fiber embedded sheet of Fig. 2(a). As shown in Fig. 2(a), the second optical fiber embedded sheet has a configuration in which a substrate 21, a pressure-sensitive adhesive layer 22, and a tacky adhesive layer 23 are laminated, and at least a portion of each of the multiple optical fibers 24 (first optical fiber 24a, second optical fiber 24b) is embedded in the tacky adhesive layer 23.

[0052] (1.3. Third optical fiber embedded sheet) Fig. 3 is a diagram showing a third optical fiber embedded sheet according to another embodiment of the present invention. The third optical fiber embedded sheet is a strip-shaped sheet material having a plurality of adhesive layers 33 (first adhesive layer 33a, second adhesive layer 33b) on an adhesive layer 32, and a plurality of optical fibers 34 (optical fibers 34a, optical fibers 34b) used as sensors embedded in each adhesive layer 33 so as to be partially embedded. In Fig. 3, at least one optical fiber is embedded in each of the two adhesive layers so as to be partially embedded, but the number of adhesive layers and optical fibers is not limited to this and may be two or more, or three or more, respectively. Furthermore, a plurality of optical fibers may be embedded in one adhesive layer so as to be partially embedded. Furthermore, unless otherwise specified, the explanations given for the first embodiment of the optical fiber embedded sheet described above apply to each configuration of the third optical fiber embedded sheet of this embodiment.

[0053] Fig. 3(a) is a cross-sectional view perpendicular to the longitudinal direction of the third optical fiber embedded sheet, and Fig. 3(b) is a top view of the third optical fiber embedded sheet of Fig. 3(a). As shown in Fig. 3(a), the third optical fiber embedded sheet has a structure in which a substrate 31, a pressure-sensitive adhesive layer 32, and a pressure-sensitive adhesive layer 33 (first pressure-sensitive adhesive layer 33a, second pressure-sensitive adhesive layer 33b) are laminated together, and at least a portion of the optical fiber 34a is embedded in the first pressure-sensitive adhesive layer 33a, and at least a portion of the optical fiber 34b is embedded in the second pressure-sensitive adhesive layer 33b.

[0054] Furthermore, in the third optical fiber embedded sheet, the width Y (cm) of the adhesive layer 33 means the sum of the widths of the multiple adhesive layers, and for example, in (a) of Figure 3, it means the sum (Y1 + Y2) of the width Y1 of the first adhesive layer 33a and the width Y2 of the second adhesive layer 33b.

[0055] (2. Optical fiber installation method) Next, a description will be given of a method for installing the optical fibers 14 using the optical fiber embedded sheet 1. In this embodiment, the optical fiber embedded sheet 1 is adhered to an installation target of the optical fibers 14 with the pressure-sensitive adhesive layer 12 and the adhesive layer 13, and then the optical fibers 14 are installed by bonding the optical fiber embedded sheet 1 to the installation target with the adhesive layer 13. The installation target is, for example, concrete members or steel members that constitute pillars, beams, girders, floors, walls, etc. of a structure, but is not particularly limited thereto.

[0056] One embodiment of a method for installing the optical fiber 14 is to apply a primer 9 to the installation target 3, which hardens the adhesive layer 13 through a chemical reaction with the adhesive layer 13, and then attach the optical fiber embedded sheet 1 to the installation target at the application position of the primer 9.

[0057] In this embodiment, when installing an optical fiber, first, a primer 9 is applied to the installation surface of the installation target 3 on which the optical fiber is to be installed, as shown in Fig. 4. In this embodiment, the optical fiber 14 is installed on the lower surface of the installation target 3, and the primer 9 is applied to this lower surface, but the installation surface of the optical fiber (the surface on which the primer 9 is applied) is not particularly limited.

[0058] The primer 9 is applied in a strip shape in accordance with the attachment position of the optical fiber embedded sheet 1. Fig. 4(a) is a cross section of the application position of the primer 9 viewed along its longitudinal direction, and Fig. 4(b) is a cross section taken along line AA in Fig. 4(a).

[0059] As described above, in this embodiment, a material that cures the adhesive layer 13 through a chemical reaction with the adhesive layer 13 is used as the primer 9. For example, an epoxy resin curing agent is used as the primer 9. Although not particularly limited, examples thereof include an imidazole compound and an amine compound.

[0060] Examples of the imidazole compound include methylimidazole, 2-ethyl-4-methylimidazole, 1-isobutyl-2-methylimidazole (IBMI12), 1-benzyl-2-methylimidazole (1B2MZ), 1,2-dimethylimidazole (1,2DMZ), 1-butylimidazole (1BZ), 1-decyl-2-methylimidazole (1D2MZ), 1-octylimidazole (1OZ), 2-ethyl-4-methylimidazole, ethylimidazole, isopropylimidazole, 2,4-dimethylimidazole (2E4MZ), 1-phenylimidazole (1PZ), undecylimidazole, heptadecylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Imidazole, and from the viewpoint of curing speed, 1-substituted imidazole compounds are preferred.

[0061] Examples of the amine compound include ethylenediamine, propylenediamine, diethylenetriamine, triethylenetetramine, amine adducts thereof, metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

[0062] The primer 9 is preferably a curing agent having catalytic activity for epoxy resins, and a specific example thereof is an imidazole compound. Primer 9 can be used alone or in combination of two or more kinds. If the curing agent is in a solid form, the curing agent may be dissolved in a solvent as necessary to prepare a varnish for use.

[0063] However, the materials listed above are only examples, and the combination of the materials of the primer 9 and the adhesive layer 13 is not particularly limited as long as the adhesive layer 13 can be cured by a chemical reaction between the primer 9 and the adhesive layer 13, and the type of chemical reaction is also not particularly limited.

[0064] After applying the primer 9 in this manner, the optical fiber embedded sheet 1 is adhered to the installation target 3 by the pressure-sensitive adhesive layer 12 and the adhesive layer 13. The primer 9 then penetrates the adhesive layer 13, hardening the adhesive layer 13 and adhering the optical fiber embedded sheet 1 to the installation target 3 by the adhesive layer 13. The optical fiber embedded sheet 1 is attached to the installation target 3 at the application position of the primer 9, and at this time the positions of the optical fibers 14 are aligned with the application position of the primer 9.

[0065] Another embodiment of the optical fiber installation method is to apply a primer 9 to the adhesive layer 13, which hardens the adhesive layer 13 by chemical reaction with the adhesive layer 13, and then bring the adhesive layer 13 into contact with the installation target 3 and attach the optical fiber embedded sheet 1.

[0066] In this embodiment, when installing the optical fiber 14, first, a primer 9 is applied to the surface of the adhesive layer 13, which cures the adhesive layer 13 through a chemical reaction. After the primer 9 is applied, the optical fiber embedded sheet 1 is adhered to the installation target 3 by the adhesive layer 12 and the adhesive layer 13. The primer 9 penetrates the adhesive layer 13, which cures the adhesive layer 13, and the adhesive layer 13 adheres the optical fiber embedded sheet 1 to the installation target 3.

[0067] In this embodiment, when attaching the optical fiber embedded sheet 1, an attachment device 5 shown in FIG. 5(a) may be used.

[0068] The laminating device 5 has a main body 51, a mounting member 52, a pressure roller 53, a reel 54, etc. The main body 51 is a rod-shaped member, and the pressure roller 53 is provided at the tip of the main body 51. The reel 54 has the optical fiber embedded sheet 1 wound in a roll shape, and is attached to the main body 51 at the middle in the longitudinal direction via the mounting member 52.

[0069] The worker grasps the base end of the main body 51, which is the end opposite the pressure roller 53, and while pressing the optical fiber embedded sheet 1 unwound from the reel 54 against the installation target 3 with the pressure roller 53, moves the attachment device 5 in the attachment direction of the optical fiber embedded sheet 1 (the direction in which the optical fiber embedded sheet 1 is attached) as shown by arrow a in Figure 5 (a).

[0070] At this time, the pressure roller 53 and the reel 54 rotate as indicated by arrows b and c, respectively, in a plane (the plane shown in FIG. 5(a)) perpendicular to the installation surface of the optical fibers 14, and the pressure-sensitive adhesive layer 12 and the tacky adhesive layer 13 of the optical fiber embedded sheet 1 unwound from the reel 54 are sequentially adhered or bonded to the installation target 3 by the pressure roller 53. By setting the rotational resistance T of the reel 54 to an appropriate value, the attachment work can be performed while applying a certain initial tension resulting from the rotational resistance T to the optical fibers 14 of the optical fiber embedded sheet 1.

[0071] By attaching the optical fiber embedded sheet 1 to the installation target 3 at the application position of the primer 9, the adhesive layer 13 hardens through a chemical reaction with the primer 9, and a hardened portion 131 of the adhesive layer 13 is formed as shown in Fig. 5(b) . The hardened portion 131 is formed in at least a part of the periphery of the optical fiber 14, but the formation range of the hardened portion 131 differs depending on the application width and application amount of the primer 9, and is not particularly limited.

[0072] By hardening the adhesive layer 13 in this manner, the optical fiber 14 is firmly fixed to the installation target 3, and the integrity of the optical fiber 14 and the installation target 3 is improved.

[0073] If the optical fiber embedded sheet 1 attached to the installation target 3 is exposed to sunlight, such as outdoors, or if concrete is poured under the installation target 3 and the optical fiber embedded sheet 1 is to be in contact with concrete, the optical fiber embedded sheet 1 may be covered with a coating material 7 as shown in Figure 5(c). In the former case, an ultraviolet-resistant material is used for the coating material 7, and in the latter case, an alkali-resistant material is used for the coating material 7, thereby effectively preventing deterioration of the optical fiber embedded sheet 1.

[0074] In this manner, the optical fiber 14 is installed on the installation target 3. Thereafter, the end of the optical fiber 14 embedded in the adhesive layer 13 is taken out and connected to a measuring device (not shown), and deformation of the installation target 3 is detected from the strain of the optical fiber 14. Known measurement methods for this purpose include BOTDR (Brillouin Optical Time Domain Reflectometer), BOCDA (Brillouin Optical Correlation Domain Analysis), and FBG (Fiber Bragg Grating), and any of these methods can be applied, and the optical fiber 14 and measuring device appropriate for each method may be used.

[0075] According to the present embodiment described above, the optical fiber embedded sheet 1 is adhered to the installation target 3 using its adhesive layer 12 and adhesive layer 13, and then bonded using the adhesive layer 13, thereby increasing the adhesive strength of the optical fiber embedded sheet 1, achieving sufficient temporary fixation, and preventing the sheet from peeling off until the adhesive layer 13 has completely hardened. Furthermore, by adhering the optical fiber embedded sheet 1 to the installation target 3 using its adhesive layer 12 and tacky adhesive layer 13, and then bonding it with the tacky adhesive layer 13, the labor required for installing the optical fiber 14 can be reduced, making it possible to perform efficient installation work with a small number of people. Furthermore, the substrate 11, adhesive layer 12, and tacky adhesive layer 13 of the optical fiber embedded sheet 1 function as protective layers for the optical fiber 14, reducing the risk of damage to the optical fiber 14 due to external contact during and after installation. Furthermore, at least a portion of the optical fiber 14 is embedded in the adhesive layer 13, and no sheet or the like is interposed between the optical fiber 14 and the installation target 3. Therefore, deformation of the installation target 3 is easily reflected in the measurement results by the optical fiber 14, enabling suitable sensing, and the layer structure is simple and low-cost.

[0076] In addition, in this embodiment, the adhesive layer 13 in which the optical fiber 14 is embedded is hardened by reacting with the primer 9, thereby improving the integrity of the optical fiber 14 and the installation target 3, preventing it from easily coming off and improving durability.

[0077] Furthermore, in this embodiment, by using the above-mentioned attachment device 5 when attaching the optical fiber embedded sheet 1, the attachment work of the optical fiber embedded sheet 1 is further simplified, even by one person, and attachment accuracy is improved. Also, since the attachment work can be performed while applying a constant initial tension to the optical fibers 14 of the optical fiber embedded sheet 1, a constant initial strain can be introduced over the entire length of the optical fibers 14, preventing variation in measurement results.

[0078] However, it is also possible to attach the optical fiber embedded sheet 1 without using the attachment device 5, and it is also possible to use an attachment device 5a shown in FIG. 6 further reduces the optical fiber installation work by adding a primer applicator 57 to the above-mentioned applicator 5, thereby enabling application of the primer 9 and application of the optical fiber embedded sheet 1 in a single operation. Note that the applicator 5a can be used in the above-mentioned optical fiber installation modes in which the primer 9, which hardens the adhesive layer through a chemical reaction with the adhesive layer, is applied to the installation target 3, and then the optical fiber embedded sheet 1 is attached to the installation target 3 at the application position of the primer 9.

[0079] The primer applicator 57 is attached to the tip of a support member 55 extending from the middle of the main body 51 of the laminating device 5a, and in the example of Fig. 6, an auxiliary roller 58 that assists the running of the laminating device 5a is attached to the middle of the main body 51 via a mounting member 56. The pressure roller 53, primer applicator 57, and auxiliary roller 58 are arranged in this order in the laminating direction a of the optical fiber embedded sheet 1.

[0080] The worker grasps the base end of the main body 51, presses the pressure roller 53, primer applicator 57, and auxiliary roller 58 against the installation target 3, and moves the attachment device 5a in the attachment direction a of the optical fiber embedded sheet 1 while using the pressure roller 53 to press the optical fiber embedded sheet 1 unwound from the reel 54 toward the installation target 3. This causes the primer applicator 57 to apply the primer 9 before attaching the optical fiber embedded sheet 1, allowing this series of operations to be performed by one person. The support member 55 may be provided with an expansion / contraction mechanism using a spring or the like, which allows the primer applicator 57 to follow the irregularities of the surface of the installation target 3 and ensures that the required amount of primer 9 is always applied.

[0081] In this embodiment, the adhesive layer 13 of the optical fiber embedded sheet 1 is cured by the primer 9 applied to the installation target 3, but the adhesive layer 13 of the optical fiber embedded sheet 1 may be bonded to the installation target 3 without applying the primer 9. In this case, there is no need to cure the adhesive layer 13 by a chemical reaction with the primer 9.

[0082] When the adhesive layer 13 of the optical fiber embedded sheet 1 is adhered to the installation object 3 without applying the primer 9, and when the adhesive layer 13 is hardened with the primer 9, the latter allows for more sensitive detection of locations where distortion has occurred in the optical fiber 14 due to deformation of the installation object 3.

[0083] The reason for this will be explained using the example of a case where a crack 3a occurs in the installation target 3 as shown in Figures 7(a) and 7(b). Figures 7(a) and 7(b) show cross sections along the longitudinal direction of the optical fiber 14.

[0084] That is, in the case of FIG. 7(a) in which the adhesive layer 13 of the optical fiber embedded sheet 1 is adhered to the installation target 3 without applying a primer, the crack 3a of the installation target 3 has a certain length L a7(b) in which the adhesive layer 13 is hardened by the primer, the optical fiber 14 is firmly fixed to the installation target 3, so the crack 3a of the installation target 3 is fixed to the short length L b The optical fiber 14 outside this range is firmly fixed to the installation target 3, so no strain occurs. b The strain ε per unit length of the optical fiber 14 in this range becomes large, and this can be detected sensitively.

[0085] In this way, by hardening the adhesive layer 13 in which the optical fiber 14 is embedded by reaction with the primer 9, the integrity of the optical fiber 14 and the installation target 3 is improved, and deformation of the installation target 3 can be sensitively detected. However, there is a risk that a small and insignificant deformation may be detected as noise, the measured value may exceed the measurable range, or the optical fiber 14 may be damaged, so in some cases it may be preferable to adhere the adhesive layer 13 to the installation target 3 without applying the primer 9. This also makes it easier to follow unevenness on the surface of the installation target 3 and deformation of the installation target 3.

[0086] Therefore, which method to adopt can be determined by taking into consideration the purpose of measurement, the installation target 3, etc., and the material of the adhesive layer 13, etc., can be selected so that the rigidity of the cured portion 131 when cured with primer 9, or the rigidity of the adhesive layer 13 itself when not cured, is an appropriate value depending on the purpose of measurement, the installation target 3, etc.

[0087] Furthermore, the substrate 11 is not limited to the above, and may be a high-strength layer using a carbon fiber sheet, an aramid sheet, etc. Also, a scale may be provided in the longitudinal direction of the substrate 11 so that the applied length of the optical fiber embedded sheet 1 can be grasped.

[0088] Furthermore, the configuration of the optical fiber embedded sheet is not limited to that described above, and for example, as shown in the optical fiber embedded sheet 1a in Fig. 8, in addition to the optical fiber 14 described above, an optical fiber 15 used as a sensor for measuring temperature may be further embedded in the adhesive layer or its cured portion 131. The optical fiber 15 is used to measure the temperature distribution along its longitudinal direction, and is arranged parallel to the optical fiber 14 along the longitudinal direction of the optical fiber embedded sheet 1a.

[0089] 8, a cylindrical body 16 is embedded in the adhesive layer or its hardened portion 131, and an optical fiber 15 for temperature measurement is inserted into the cylindrical body 16, thereby cutting the edge between the optical fiber 15 and the adhesive layer or its hardened portion 131. The outer diameter of the optical fiber 15 is smaller than the inner diameter of the cylindrical body 16, and the optical fiber 15 is arranged with some slack to prevent distortion. In this case, the temperature distribution measured by the optical fiber 15 in the longitudinal direction can be used to perform temperature correction on the measurement results by the optical fiber 14, enabling more accurate detection of deformation of the installation target 3.

[0090] In addition, only the optical fiber 15 for the purpose of temperature measurement may be embedded in the adhesive layer or its hardened portion 131. In this case, there is also an advantage that the temperature in the vicinity of the installation object 3 is more likely to be reflected in the measurement results by the optical fiber 15, since no sheet or the like is interposed between the optical fiber 15 and the installation object 3.

[0091] In addition, to simplify the process of connecting the optical fiber 14 to the measuring instrument, a wire 17 for tearing the sheet along the longitudinal direction of the optical fiber 14 may be embedded near the optical fiber 14, as shown in the optical fiber embedded sheet 1c in Figure 9(a).

[0092] Steel or stainless steel, for example, can be used for the wire 17, and after the optical fiber embedded sheet 1c is attached, for example, before the adhesive layer is completely cured by the primer 9, the end of the wire 17 protruding from the longitudinal end of the optical fiber embedded sheet 1c, or the end of the wire 17 extracted from the optical fiber embedded sheet 1c by making an incision in the substrate 11, etc., is pulled toward the outside of the optical fiber embedded sheet 1c, i.e., toward the substrate 11, as shown by arrow d in Figure 9(a) . This causes the optical fiber embedded sheet 1c to tear, forming a tear portion 111, as shown in Figure 9(b), which makes it easy to extract the optical fiber 14 inside and simplify the process of connecting it to a measuring device.

[0093] As mentioned above, the number of optical fibers 14 is not limited to one, and it is also possible to arrange multiple optical fibers 14 (two in the illustrated example) in parallel along the longitudinal direction of the optical fiber embedded sheet 1d, as shown in the optical fiber embedded sheet 1d in Fig. 10(a). In this case, even if one optical fiber 14 is broken, measurement can be continued using the other optical fibers 14, reducing the risk of measurement becoming impossible due to a break. Furthermore, when performing measurement using BOCDA, the ends of the two optical fibers 14 on the same side can be connected with an optical connector (not shown) or the like, and the round trip path of the optical fiber 14 required for measurement can be easily configured.

[0094] Furthermore, the optical fibers 14 are not limited to those that are installed in only one direction, and multiple optical fibers 14 may be installed in different directions, as shown in the optical fiber embedded sheet 1e of Figure 10(b). In the example of Figure 10(b), the optical fibers 14 are arranged in two perpendicular directions on a plane, allowing measurements in each direction to be performed simultaneously. It is difficult to accurately arrange optical fibers in multiple directions at a construction site, but by using an optical fiber embedded sheet 1e in which optical fibers 14 are installed in multiple directions in advance, the optical fibers 14 can be installed accurately in the desired direction.

[0095] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas disclosed in this application, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Example]

[0096] Hereinafter, the embodiment of the present invention will be described in more detail using examples.

[0097] (Adhesive strength measurement) The adhesive layer and adhesive surface of the pressure-sensitive adhesive layer of the optical fiber embedded sheet were placed on a 2.0 mm thick SS400 plate. After bonding, the sheets were pressed together by rolling a 2 kg roller back and forth once. Three minutes after bonding, the peel adhesion strength (N) was measured using a tension and compression tester (device name "TG-1kN", manufactured by Minebea Co., Ltd.) at a peel angle of 180° and a peel speed of 300 mm / min, and the adhesive strength was calculated using the following formula. Adhesive strength (N / 10mm) = Peel adhesive strength (N) / width of adhesive layer x (cm) The adhesive strength was evaluated as follows: ◎: Adhesive strength is 1.00N / 10mm or more 〇: Adhesive strength is 0.75N / 10mm or more and less than 1.00N / 10mm ×: Adhesive strength is less than 0.75N / 10mm The results are shown in Table 1 and FIG.

[0098] (Measurement of tape feeding force) The adhesive layer and adhesive layer of the optical fiber embedded sheet were placed on the PVDF side of a resin film (KFC Film, FT-50Y, manufactured by Kureha Extron Co., Ltd.). After lamination, the sheets were pressed together with a 2 kg roller, rolling it back and forth once. 24 hours after pressing, the peel adhesion strength (N) was measured using a tension and compression tester (TG-1kN, manufactured by Minebea Co., Ltd.) at a peel angle of 180° and a peel speed of 300 mm / min. Tape pulling force (N / 10mm) = Peel adhesive strength (N) / width of adhesive layer x (cm) The tape payout force was evaluated as follows: ◎: Tape feeding force is 4.00N / 10mm or less 〇: Tape feeding force is 5.00N / 10mm or less, over 4.00N / 10mm ×: Tape feeding force is over 5.00N / 10mm The results are shown in Table 2 and FIG.

[0099] Example 1 (Adhesive layer) A pressure-sensitive adhesive composition was prepared by mixing 20 mass% of a liquid polyfunctional phenol novolac epoxy resin (trade name "jER152", manufactured by Mitsubishi Chemical Corporation), 30 mass% of a solid bisphenol A epoxy resin (trade name "jER1256", manufactured by Mitsubishi Chemical Corporation), and 50 mass% of an acrylic rubber particle-dispersed bisphenol A epoxy resin (trade name "Acryset BPA 328", manufactured by Nippon Shokubai Co., Ltd., acrylic rubber particles: 20 mass%, average particle size=200 to 300 nm), and then diluting the mixture with methyl ethyl ketone to a concentration of 60% to prepare a pressure-sensitive adhesive composition. This was coated onto the release-treated surface of a release-treated polyethylene terephthalate film (PET film) (trade name "Diafoil MRF#38", manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 50 μm, and then heated and dried at 80° C. for 3 minutes to obtain a pressure-sensitive adhesive layer. Thereafter, the pressure-sensitive adhesive layer was brought into contact with another polyethylene terephthalate film so that the pressure-sensitive adhesive layer was sandwiched between the two polyethylene terephthalate films, to obtain a pressure-sensitive adhesive sheet.

[0100] (Adhesive layer) As the adhesive, double-sided adhesive tape (trade name "Hyper Joint H9008", manufactured by Nitto Denko Corporation, thickness 0.8 mm) was used.

[0101] (base material) A resin film (KFC Film, FT-50Y, manufactured by Kureha Extron Co., Ltd., thickness: 50 μm) was used as the substrate. The resin film has a PVDF surface and an acrylic resin surface.

[0102] (optical fiber) The optical fiber used was coated with acrylic resin (outer diameter Φ500 μm).

[0103] (Primer) As a primer, an 80% by mass ethanol solution of 1,2-dimethylimidazole (manufactured by Shikoku Chemicals Co., Ltd.) was used.

[0104] (Production of optical fiber embedded sheet) First, a double-sided adhesive tape was attached to the acrylic resin surface of the substrate so as to have the width shown in Table 1 below, thereby forming an adhesive layer. Next, an optical fiber was laminated so as to be positioned at the center of the width direction of the adhesive layer. Then, the width of the adhesive sheet prepared above was adjusted to have the width shown in Table 1 below, the PET film was peeled off, and the tape was attached to the adhesive layer so as to surround the optical fiber. After all layers were laminated, a 2 kg roller was rolled back and forth once to press them together, thereby obtaining an optical fiber embedded sheet of Example 1. The substrate had the same width as the adhesive layer.

[0105] Examples 2 to 7, Comparative Example 1 Optical fiber embedded sheets of Examples 2 to 7 and Comparative Example 1 were obtained in the same manner as in Example 1, except that the width X of the pressure-sensitive adhesive layer and the width Y of the adhesive layer were changed as shown in Table 1.

[0106] [Table 1]

[0107] The results in Table 1 show that the optical fiber embedded sheet of the example has a pressure-sensitive adhesive layer that is wider and has higher adhesive strength than the adhesive layer, so it has sufficient temporary fixation until attachment to the installation target is complete. In addition, the optical fiber embedded sheet of the example has low tape payout force, so it is easy to work with and can suppress excessive stress on the optical fiber. On the other hand, the optical fiber embedded sheet of the comparative example had the same width for the adhesive layer and the tacky adhesive layer, and therefore had low adhesive strength and was found to not have sufficient temporary fixation until attachment to the installation object was complete. [Explanation of symbols]

[0108] 1, 1a, 1c, 1d, 1e: Optical fiber embedded sheet 3: Installation target 5, 5a: Pasting device 7: Covering material 9: Primer 11, 21, 31: Base material 12, 22, 32: adhesive layer 13, 23, 33, 33a, 33b: Adhesive layer 14, 24, 34, 34a, 34b: Optical fiber 16: Cylinder 17: Wire rod 51: Main body 52, 56: Mounting material 53: Presser roller 54: Reel 55: Support material 57: Primer application device 58: Auxiliary roller 111: Tear part 131: Hardened part

Claims

1. An optical fiber embedded sheet incorporating an optical fiber used as a sensor, a substrate, a pressure-sensitive adhesive layer, and a pressure-sensitive adhesive layer are laminated in this order; At least a portion of the optical fiber is embedded in the adhesive layer, The pressure-sensitive adhesive layer is wider than the pressure-sensitive adhesive layer, When the width (cm) of the pressure-sensitive adhesive layer is X and the width (cm) of the pressure-sensitive adhesive layer is Y, 0.05≦Y / X≦0.95 is satisfied. Optical fiber embedded sheet.

2. 2. The optical fiber embedded sheet according to claim 1, wherein the adhesive layer is provided with a wire for tearing the sheet.

3. 3. A method for installing an optical fiber, comprising adhering the optical fiber embedded sheet according to claim 1 or 2 to an installation target using the adhesive layer and the tacky adhesive layer, and then bonding the sheet to the installation target using the hardened tacky adhesive layer.

4. 4. The optical fiber installation method according to claim 3, further comprising the steps of: applying a primer to the installation target, the primer reacting chemically with the adhesive layer to harden the adhesive layer; and then attaching the optical fiber embedded sheet to the installation target at the application position of the primer.

5. 4. The optical fiber installation method according to claim 3, further comprising applying a primer to the adhesive layer, the primer causing the adhesive layer to harden by a chemical reaction with the adhesive layer, and then contacting the adhesive layer with the installation target to attach the optical fiber embedded sheet.

6. Using a bonding device having a reel around which the optical fiber embedded sheet is wound and a pressure roller, The optical fiber installation method described in claim 3, wherein the optical fiber embedded sheet is attached by pressing the optical fiber embedded sheet unwound from the reel toward the installation target side with the pressure roller while moving the attachment device in the attachment direction of the optical fiber embedded sheet.

7. 3. A bonding device for bonding the optical fiber embedded sheet according to claim 1 or 2 to an installation target, a reel around which the optical fiber embedded sheet is wound; a presser roller for pressing the optical fiber embedded sheet unwound from the reel toward the installation target; An application device having the above structure.

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