JP5691493B2 - Optical fiber connector and manufacturing method thereof - Google Patents

Description

  The present invention relates to an optical fiber connector and a manufacturing method thereof, and in particular, an optical fiber that is easy to attach an optical fiber regardless of a substrate, easily aligns an optical fiber and an optical waveguide core, and is not easily displaced. The present invention relates to a connector and a manufacturing method thereof.

In general, an optical cable (also referred to as an optical fiber cable) is widely used for home and industrial information communication because it enables high-speed communication of a large amount of information. For example, automobiles are equipped with various electrical components (for example, a car navigation system), and are also used for optical communication of these electrical components. As an optical cable connector for connecting the ends of optical fibers included in such an optical cable, there is one disclosed in Patent Document 1.
In addition, with the increase in information capacity, development of optical interconnection technology using optical signals not only for communication fields such as trunk lines and access systems but also for information processing in routers and servers is underway. Specifically, since light is used for short-distance signal transmission between boards in a router or server device, the optical transmission path has a higher degree of freedom of wiring and higher density than optical fibers. Possible optical waveguides are used.
An example of a method for joining the optical waveguide and the optical fiber is an optical fiber connector described in Patent Document 2.
However, in such an optical fiber connector, it is necessary to cut the optical fiber mounting groove by dicing, so that the work efficiency is low, and the optical waveguide core is formed by photolithography and process in a process different from the groove cutting process. Since the optical fiber is manufactured by etching, the optical fiber may be misaligned. Furthermore, if the above method is not formed on a hard substrate with good dimensional stability such as a silicon wafer, a larger optical fiber misalignment occurs.
In addition, the waveguide substrate on which the optical waveguide described in Patent Document 3 is formed and the optical connector on which the optical fiber is carrier are mounted on different holders, and the optical fiber and the optical fiber that fix the end faces of each holder are fixed. There is a method for connecting waveguides, but the number of steps until connection is large and complicated.
Further, it has been desired to make it easy to attach the optical fiber when connecting the optical fiber and the optical waveguide.

JP 2010-48925 JP 2001-201646 A JP-A-7-13040

  The present invention has been made in order to solve the above-described problems. An optical fiber connector and an optical fiber connector in which the alignment between the optical fiber and the optical waveguide core is easy, the optical fiber can be easily attached, and the positional deviation is difficult to be performed regardless of the substrate. It aims at providing the manufacturing method.

  In order to solve the above problems, the present inventor uses an optical fiber guide member in which a core pattern for a fiber guide having a groove for fixing an optical fiber is formed, and an optical fiber connector in which the optical waveguide is provided in parallel with the optical waveguide. The present inventors have found that the above problem can be solved by increasing the width of the groove from the joint portion on the optical fiber and optical waveguide side toward the opposite side. The present invention has been completed based on such findings.

That is, the present invention provides the following inventions.
(1) An optical fiber guide member in which a fiber guide core pattern having a groove for fixing an optical fiber is formed on a substrate;
An optical signal transmission core pattern is formed on the first lower clad layer, and an optical waveguide having an upper clad layer formed on the optical signal transmission core pattern is provided in parallel.
The groove of the fiber guide core pattern is formed from the opposite side of the optical waveguide to the groove so that the optical fiber is bonded to a position where the optical signal can be transmitted to the optical signal transmission core pattern of the optical waveguide. An optical fiber connector for guiding an end of the optical fiber to be inserted into the optical waveguide,
An optical fiber connector in which the groove has a width that increases from the joint between the optical fiber and the optical waveguide toward the opposite side.
(2) The optical fiber connector according to (1), wherein a fiber guide core pattern and a cover material covering the upper cladding layer on the fiber guide core pattern are formed.
(3) The optical signal transmission core pattern is formed on a first lower clad layer formed on the substrate, and the fiber guide core pattern is formed on the substrate. The optical fiber connector as described in 2).
(4) The optical fiber connector according to any one of (1) to (3), wherein the substrate has an adhesive layer, and the first lower cladding layer and the fiber guide core pattern are formed on the adhesive layer. .
(5) The optical fiber connector according to (4), wherein the adhesive layer is a second lower cladding layer.
(6) The optical fiber connector according to any one of (1) to (4), wherein an upper cladding layer is provided on the fiber guide core pattern.
(7) The optical waveguide of the optical fiber connector is an optical waveguide with an optical path conversion mirror, and the lid member has a function as a reinforcing material for the optical path conversion mirror. The optical fiber connector as described.
(8) The optical fiber connector according to any one of (1) to (7), wherein the substrate is an electric wiring board.
(9) A first lower clad layer forming film is laminated on a substrate, and the first lower clad layer forming film is etched to form a first lower clad layer at a site where a groove for fixing an optical fiber is formed. A core forming film is laminated on the substrate from which the first lower cladding layer and the first lower cladding layer forming film have been removed by the first step of removing the film for forming the first lower cladding layer and the first step; A method for manufacturing an optical fiber connector, comprising: a second step of forming a core pattern for guiding and a core pattern for transmitting optical signals at once, wherein the groove of the core pattern for fiber guiding is from the side opposite to the optical waveguide An end portion of the optical fiber inserted into the groove is guided to the optical waveguide, and the groove joins the optical fiber and the optical waveguide side. Toward et opposite method of manufacturing an optical fiber connector for forming the fiber guide core pattern so that the width is increased.
(10) The method for manufacturing an optical fiber connector according to (9), further including a third step of forming a cover material covering the fiber guide core pattern after the second step.
(11) Between the second step and the third step, an upper clad layer forming film is laminated from the fiber guide core pattern and the optical signal transmission core pattern forming surface side, and light is etched. The method for manufacturing an optical fiber connector according to (10), further including a fourth step of removing the film for forming the upper clad layer in the groove portion for fixing the fiber.
(12) A fifth step of forming a slit groove by a dicing saw immediately before or after the fourth step is characterized in that the depth of the slit groove is equal to or less than the surface of the first lower cladding layer. The manufacturing method of the optical fiber connector according to (10) or (11).

  The optical fiber connector of the present invention makes it easy to align the optical fiber and the optical waveguide core without depending on the substrate, makes it easy to attach the optical fiber, and makes it difficult to shift the position of the optical fiber. The optical fiber and the optical waveguide can be easily coupled simply by being inserted into the space formed by the above.

FIG. 2 is a cross-sectional view (a) in a fiber guide core pattern parallel direction showing the optical fiber connector of the present invention, and a cross-sectional view (b) in a parallel direction of a light transmission core pattern and grooves. FIG. 2 is a cross-sectional view (c) perpendicular to a light transmitting core pattern and a core pattern for a fiber guide according to the present invention; It is a top view which shows the optical fiber connector of this invention. It is a principal part enlarged plan view of the optical fiber connector of the present invention. It is a perspective view of an optical fiber connector.

The optical fiber connector of the present invention will be described with reference to FIGS. 5 is a diagram showing a state before processing the optical fiber guide core pattern 5, and in the present invention, the optical fiber guide core pattern 5 is as shown in FIG. The width increases from the joint between the optical fiber 30 and the optical waveguide 20 toward the opposite side.
The optical fiber connector of the present invention is an optical fiber in which a fiber guide core pattern 5 having grooves 8 (hereinafter sometimes referred to as “fiber grooves”) for fixing the optical fibers 30 on the substrate 1 is formed. The guide member 10 and the optical waveguide 20 having the optical signal transmission core pattern 4 formed on the first lower cladding layer 3 and the upper cladding layer 6 formed on the optical signal transmission core pattern are juxtaposed. It has a structure.
In the present invention, it is preferable that both the depth of the groove 8 and the lateral width a of the joint between the optical fiber 30 and the optical waveguide 20 are equal to or larger than the diameter of the optical fiber 30 fixed in the groove of the optical fiber guide member. . That is, when the depth of the groove is larger than the diameter of the optical fiber 30 and the width a of the groove is larger than the diameter of the optical fiber 30, the optical fiber 30 can be easily inserted into the groove 8. It is preferable that the optical fiber guide member 10 is formed with a lid member 7 that covers the core pattern 5 because it can be more easily inserted.
A feature of the present invention is that the optical fiber 30 is joined to the optical signal transmitting core pattern 4 of the optical waveguide at a position where the optical signal can be transmitted in a state where the optical fiber 30 is inserted. An optical fiber in which optical waveguides 20 are arranged in parallel and the grooves 8 of the fiber guide core pattern 5 guide the end portions of the optical fibers 30 inserted into the grooves 8 from the side opposite to the optical waveguides 20 to the optical waveguides 20. It is a connector, Comprising: The groove | channel 8 has the opening width large toward the opposite side from the junction part by the side of the optical fiber 30 and the optical waveguide 20 (refer FIG. 4).
As described above, by increasing the width of the insertion portion of the optical fiber 30, it becomes easier to insert the optical fiber into the groove 8 of the fiber guide core pattern 5.
As the shape of the fiber guide core pattern 5 forming the groove 8, as shown in FIG. 4, a shape having a curved surface shape from the joint portion toward the opposite side (see FIG. 4A), linear (See FIG. 4B) and the like.

In the present invention, it is preferable that the optical signal transmission core pattern 4 is formed on the first lower clad layer 3 formed on the substrate 1 and the fiber guide core pattern 5 is formed on the substrate 1.
It is preferable that the substrate 1 has an adhesive layer 2, and the first lower cladding layer 3 and the fiber guide core pattern 5 are formed on the adhesive layer 2.
The adhesive layer 2 is preferably the second lower cladding layer 201.
The optical waveguide 20 in the present invention preferably has the optical path conversion mirror 11, and in that case, it is preferable that the lid member 7 also has a reinforcing plate of the optical path conversion mirror 11.

In the optical fiber guide member 10, the fiber guide core pattern 5 is preferably formed on the second lower cladding layer 201 which is a part of the substrate 1.
In the present invention, the fiber guide core pattern 5 is for fixing the optical fiber 30 and does not function as a core for transmitting optical signals.
Further, although there is no limitation on the optical fiber to be used, when it is expressed as “optical fiber diameter” below, it represents the cladding outer diameter of the optical fiber or the coating outer diameter of the optical fiber.
Moreover, it is preferable to have an upper clad layer 6 on the fiber guide core pattern 5 in the optical fiber guide member 10. By having the upper clad layer 6, the flatness of the optical fiber connector of the present invention is improved.

Hereinafter, each layer constituting the optical fiber connector of the present invention will be described.
(Lower cladding layer and upper cladding layer)
Hereinafter, the lower clad layers (first lower clad layer, second lower clad layer) 201 and 3 and the upper clad layer 6 used in the present invention will be described. As the lower cladding layers 201 and 3 and the upper cladding layer 6, a cladding layer forming resin or a cladding layer forming resin film can be used.

  The clad layer forming resin used in the present invention is not particularly limited as long as it is a resin composition that has a lower refractive index than the optical signal transmission core pattern 4 and is cured by light or heat, and a thermosetting resin composition or photosensitive resin. Can be suitably used. The resin composition used for the resin for forming the clad layer may be the same or different in the components contained in the resin composition in the lower clad layers 201 and 3 and the upper clad layer 6. The refractive indexes may be the same or different. Further, the second lower clad layer 201 is not required to have a refractive index or a photocurable property as long as it has a function as the adhesive layer 2, and an adhesive or a core forming resin film described later may be used.

In the present invention, the method for forming the clad layer is not particularly limited, and for example, the clad layer may be formed by applying a clad layer forming resin or laminating a clad layer forming resin film.
In the case of application, the method is not limited, and the clad layer forming resin composition may be applied by a conventional method.
The clad layer-forming resin film used for laminating can be easily produced by, for example, dissolving the clad layer-forming resin composition in a solvent, applying it to a carrier film, and removing the solvent.

The thicknesses of the lower cladding layers 201 and 3 and the upper cladding layer 6 are not particularly limited, but the thickness after drying is preferably in the range of 5 to 500 μm. When the thickness is 5 μm or more, a clad thickness necessary for light confinement can be secured, and when the thickness is 500 μm or less, it is easy to control the film thickness uniformly. From the above viewpoint, it is more preferable that the thicknesses of the lower cladding layers 201 and 3 and the upper cladding layer 6 are further in the range of 10 to 100 μm. The first lower clad layer 3 has a cured film thickness of [(radius of optical fiber) − (first lower clad layer 3) in order to align the center of the optical fiber with the optical signal transmission core pattern. It is more preferable to use a film having a thickness of the optical signal transmission core pattern formed on top) / 2].
As a specific example, a preferable thickness of the lower cladding layer 3 when an optical fiber having an optical fiber diameter of 80 μm and an optical fiber core diameter of 50 μm is used is shown. First, when the optical signal propagates from the optical fiber to the optical signal transmission core pattern, the square circumscribing the core diameter of the optical fiber can propagate without optical loss. In this case, the core of the optical waveguide is 50 μm × 50 μm (core height: 50 μm). Applying the above formula, the optimum thickness of the lower cladding layer 3 is 15 μm. Further, when an optical signal propagates from the optical fiber to the optical signal transmission core pattern using the same optical fiber as described above, a square inscribed in the core diameter of the optical fiber can propagate without optical loss. In this case, the core of the optical waveguide is 40 μm × 40 μm (core height: 40 μm). Applying the above equation, the optimum thickness of the lower cladding layer 3 is 20 μm.
In the optical waveguide 20, the thickness of the upper clad layer 6 for embedding the optical signal transmission core pattern 4 is preferably equal to or greater than the thickness of the core pattern 4, but from the substrate 1 surface to the upper clad layer upper surface. What is necessary is just to adjust suitably so that height may become more than the diameter of an optical fiber, and adjusting to a groove | channel higher 0.1-15 micrometers than the diameter of an optical fiber is more preferable. The thickness of the upper clad layer formed on the fiber guide core pattern may be adjusted to the same height as described above.

(Core layer forming resin and core layer forming resin film)
In the present invention, the method for forming the core layer laminated on the lower clad layers 201 and 3, the optical signal transmission core pattern 4, and the fiber guide core pattern 5 is not particularly limited. Alternatively, the core layer may be formed by laminating a core layer-forming resin film, and the core pattern may be formed by etching.
At this time, in the present invention, the fiber guide core pattern 5 is formed so that the width of the groove 8 increases from the joint where the optical fiber 30 and the optical waveguide 20 are joined to the opposite side.
In the present invention, the optical waveguide 20 and the optical fiber guide member 10 are each formed with a core layer, and then simultaneously etched to form the optical signal transmission core pattern 4 and the fiber guide core pattern 5 at the same time. An optical fiber connector can be manufactured well.

  The core layer forming resin, in particular, the core layer forming resin used for the optical signal transmission core pattern 4 is designed to have a higher refractive index than the cladding layer 3 and uses a resin composition capable of forming a core pattern with actinic rays. It is preferable. The method of forming the core layer before patterning is not limited, and examples thereof include a method of applying the core layer forming resin composition by a conventional method.

The thickness of the resin film for forming the core layer is not particularly limited, and the thickness of the core layer after drying is usually adjusted to be 10 to 100 μm. When the thickness of the optical signal transmission core pattern 4 after finishing the film is 10 μm or more, there is an advantage that the alignment tolerance can be increased in coupling with the light emitting / receiving element or the optical fiber after the optical waveguide is formed. In the case of the following, there is an advantage that the coupling efficiency is improved in coupling with the light emitting / receiving element or the optical fiber after the optical waveguide is formed. From the above viewpoint, the thickness of the film is preferably in the range of 30 to 90 μm, and the film thickness may be appropriately adjusted in order to obtain the thickness.
Further, when the thickness of the optical signal transmission core pattern 4 after curing is larger than the core diameter of the optical fiber when transmitting light from the optical fiber to the optical signal transmission core pattern, the loss of light is small. In the case of transmitting light from the transmission core pattern to the optical fiber, it is further preferable to adjust the rectangle formed by the thickness and width of the optical signal transmission core pattern to be inside the core diameter of the optical fiber.

(Cover material)
The material of the lid member 7 is not particularly limited, but when the upper clad layer 6 is adhesive, for example, a glass epoxy resin substrate, a ceramic substrate, a glass substrate, a silicon substrate, a plastic substrate, a metal substrate, a substrate with a resin layer , A substrate with a metal layer, a plastic film, a plastic film with a resin layer, a plastic film with a metal layer, an electric wiring board, and the like.
Furthermore, as the cover material 7 having flexibility and toughness, for example, polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyamide, polycarbonate, polyphenylene ether, polyether sulfide, polyarylate, liquid crystal Polymer, polysulfone, polyethersulfone, polyetheretherketone, polyetherimide, polyamideimide, or polyimide may be used as the lid member 7. Of these, polyamideimide and polyimide are particularly preferable from the viewpoints of heat resistance and dimensional stability.
If the upper clad layer 6 has no adhesiveness, an adhesive layer may be laminated on the lid material 7 listed above to form the lid material 7 with an adhesive layer. The thickness of the lid member 7 may be appropriately changed depending on the warp of the plate and dimensional stability, but is preferably 10 μm to 10.0 mm. Further, the thickness of the adhesive layer formed on the lid member 7 may be 0.1 μm to 50 μm, and if it is 20 μm or less, the flow of the adhesive into the groove 8 is further suppressed.

(substrate)
There is no restriction | limiting in particular as a material of the board | substrate 1, For example, a glass epoxy resin substrate, a ceramic substrate, a glass substrate, a silicon substrate, a plastic substrate, a metal substrate, a substrate with a resin layer, a substrate with a metal layer, a plastic film, with a resin layer Examples thereof include a plastic film, a plastic film with a metal layer, and an electric wiring board.
Base material having flexibility and toughness as the substrate 1, for example, polyester such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyamide, polycarbonate, polyphenylene ether, polyether sulfide, polyarylate, liquid crystal polymer, A flexible optical fiber connector may be used by using polysulfone, polyethersulfone, polyetheretherketone, polyetherimide, polyamideimide, or polyimide as a substrate. The thickness of the substrate may be appropriately changed depending on the warp and dimensional stability of the plate, but is preferably 10 μm to 10.0 mm. Further, the substrate 1 may be peeled off after the optical waveguide is formed. When the optical signal whose optical path has been changed passes through the substrate 1 without removing the substrate 1, it is preferable to use the substrate 1 that is transparent to the wavelength of the optical signal.
The electric wiring board is not particularly limited, but may be an electric wiring board in which the metal wiring 103 is formed on FR-4, or a flexible wiring board in which the metal wiring 103 is formed on polyimide or polyamide film. There may be. The metal wiring 103 can be formed from the metal layer 102.

In the present invention, the optical fiber 30 is inserted into the groove 8 or a space formed by the groove 8 and the lid member 7, and is fixed with an adhesive or the like as necessary. The optical fiber and the optical waveguide can be aligned.
At this time, alignment in the X direction shown in FIGS. 2 and 3 can be performed by the fiber guide core pattern 5, and alignment in the Z direction can be performed by the substrate 1 and / or the lid member 7.

  In the present invention, the diameter of the optical fiber is preferably 200 μm or less from the viewpoint of easy control of the film thickness of the core layer forming resin film, and it is more preferable to use an optical fiber having a diameter of 125 μm or 80 μm. As described above, the width of the groove 8 of the fiber guide core pattern 5 may be a width equal to or larger than the diameter of the optical fiber. It is preferably 1-10 μm wide.

(Manufacturing method of optical fiber connector of the present invention)
The manufacturing method of the present invention has the following steps (1) and (2) in order, and when the lid member 7 is formed, has a step (3). That is,
(1) A first lower clad layer forming film is laminated on a substrate 1 and the first lower clad layer forming film is etched to form a groove for fixing an optical fiber. A first step of removing the forming film;
(2) A core forming film is laminated on the first lower cladding layer 3 and the substrate from which the first lower cladding layer forming film has been removed in the first step, and the core pattern 5 for fiber guide is formed by etching. A second step of collectively forming the optical signal transmission core pattern 4;
(3) a third step of forming a cover material covering the fiber guide core pattern 5;
It is.

In the first step, the first lower cladding layer 3 is formed only in the portion of the optical waveguide 20 in the optical fiber connector, and the first lower cladding layer 3 is removed from the portion of the optical fiber guide member 10. . As a result, in the optical waveguide 20, a lower clad for optical transmission is formed, and the optical waveguide 20 and the optical fiber 30 are aligned in the Z direction. Therefore, the thickness of the first lower cladding layer 3 is appropriately set according to the diameter of the optical fiber 30 to be used, and the preferred thickness is as described above.
Next, in the second step, the optical signal transmission core pattern 4 is formed on the first lower cladding layer 3 in the optical waveguide 20, and the optical fiber is fixed on the substrate in the optical fiber guide member 10. The fiber guide core pattern 5 is formed.
In the present invention, in the second step, it is necessary to form the fiber guide core pattern 5 so that the width of the groove 8 increases from the joint where the optical fiber 30 and the optical waveguide 20 are joined to the opposite side. (See FIG. 4).
Finally, if necessary, the optical fiber connector of the present invention is manufactured by covering the fiber guide core pattern 5 with the lid member 7 in the third step. The method of forming the lid member 7 is appropriately determined according to the material, but it is preferable to form the lid member using a roll laminator, a vacuum laminator, or the like.

Further, in the manufacturing method of the present invention, the upper clad layer forming film is laminated between the fiber guide core pattern 5 and the optical signal transmission core pattern 4 forming surface side between the second step and the third step. Then, it is preferable to have a fourth step of removing the upper clad layer forming film in the groove 8 (fiber groove) for fixing the optical fiber 30 by etching.
By this step, the upper clad layer 6 is formed in the optical waveguide 20, and high light transmission efficiency is achieved. On the other hand, in the optical fiber guide member 10, in order to secure the groove 8, the portion of the cladding layer is removed by etching. Here, although the upper clad layer 6 on the fiber guide core pattern 5 may be removed by etching or left, as described above, in order to ensure flatness, the fiber guide core pattern 6 It is preferable to leave the upper upper cladding layer. In the step of etching and removing the upper clad layer forming resin film in the groove 8 portion, the removed portion may be on the fiber guide core pattern 5. It is preferable because the upper cladding layer 6 is formed on the fiber guide core pattern 5 to suppress the deflection of the lid member 7.

Furthermore, in the manufacturing method of the present invention, it is preferable to have a fifth step of forming the slit groove 9 with a dicing saw immediately before or after the fourth step, and in particular, the depth of the slit groove 9 is the first lower portion. The surface is preferably equal to or less than the surface of the cladding layer 3.
By this step, as will be described later, the end face of the optical waveguide connecting the optical fiber 30 and the optical waveguide 20 is smoothed. Moreover, the optical fiber 30 can be mounted favorably by setting the depth of the slit groove 9 as described above.

Further, when the optical signal transmission core pattern 4 and the fiber guide core pattern 5 are not particularly adhesive to the substrate 1, the substrate 1 with the adhesive layer 2 may be used, and the adhesive layer is the second lower cladding. The layer 201 may also be used.
Although it does not specifically limit as a kind of contact bonding layer 2, Various adhesives used for a double-sided tape, UV or a thermosetting adhesive, a prepreg, a buildup material, and an electrical wiring board manufacture use are mentioned suitably. When the optical signal passes through the substrate 1, it is sufficient that the optical signal is transparent at the wavelength of the optical signal. In this case, the substrate 1 is bonded using a resin film for forming a clad layer or a resin film for forming a core layer that has an adhesive force. Layer 2 is preferred.

  The method for smoothing the end face of the optical waveguide connecting the optical fiber 30 and the optical waveguide 20 is not particularly limited. For example, the end face of the optical waveguide is cut using a dicing saw to form the slit groove 9 and smooth the surface. You just have to. The cutting depth of the dicing blade at this time is preferably less than the surface of the substrate 1 because the optical fiber 30 can be satisfactorily mounted.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.
Example 1
[Preparation of resin film for forming clad layer]
[(A) Base polymer; production of (meth) acrylic polymer (A-1)]
46 parts by mass of propylene glycol monomethyl ether acetate and 23 parts by mass of methyl lactate were weighed in a flask equipped with a stirrer, a cooling pipe, a gas introduction pipe, a dropping funnel, and a thermometer, and stirred while introducing nitrogen gas. . The liquid temperature was raised to 65 ° C., 47 parts by weight of methyl methacrylate, 33 parts by weight of butyl acrylate, 16 parts by weight of 2-hydroxyethyl methacrylate, 14 parts by weight of methacrylic acid, 2,2′-azobis (2,4-dimethylvaleronitrile ) A mixture of 3 parts by mass, 46 parts by mass of propylene glycol monomethyl ether acetate and 23 parts by mass of methyl lactate was added dropwise over 3 hours, followed by stirring at 65 ° C. for 3 hours, and further stirring at 95 ° C. for 1 hour. A (meth) acrylic polymer (A-1) solution (solid content: 45% by mass) was obtained.
[Measurement of weight average molecular weight]
As a result of measuring the weight average molecular weight (in terms of standard polystyrene) of (A-1) using GPC (“SD-8022”, “DP-8020”, and “RI-8020” manufactured by Tosoh Corporation), 3. It was 9 × 10 ⁴ . The column used was “Gelpack GL-A150-S” and “Gelpack GL-A160-S” manufactured by Hitachi Chemical Co., Ltd.
[Measurement of acid value]
As a result of measuring the acid value of A-2, it was 79 mgKOH / g. The acid value was calculated from the amount of 0.1 mol / L potassium hydroxide aqueous solution required to neutralize the A-2 solution. At this time, the point at which the phenolphthalein added as an indicator changed color from colorless to pink was defined as the neutralization point.
[Preparation of resin varnish for forming clad layer]
(A) As the base polymer, 84 parts by mass (solid content: 45% by mass) of the A-1 solution (solid content: 45% by mass), (B) Urethane (meth) acrylate having a polyester skeleton as the photocuring component (Shin Nakamura) 33 parts by mass of “U-200AX” manufactured by Chemical Industry Co., Ltd., and 15 parts by mass of urethane (meth) acrylate having a polypropylene glycol skeleton (“UA-4200” manufactured by Shin-Nakamura Chemical Co., Ltd.), (C) heat As a curing component, 20 parts by mass of a polyfunctional block isocyanate solution (solid content: 75% by mass) obtained by protecting an isocyanurate type trimer of hexamethylene diisocyanate with methyl ethyl ketone oxime (“Sumijour BL3175” manufactured by Sumika Bayer Urethane Co., Ltd.) (Solid content 15 parts by mass), (D) As a photopolymerization initiator, 1- [4- (2-hydroxy ester) Xyl) phenyl] -2-hydroxy-2-methyl-1-propan-1-one (“Irgacure 2959” manufactured by Ciba Japan Co., Ltd.), 1 part by mass, bis (2,4,6-trimethylbenzoyl) phenylphosphine 1 part by mass of oxide (“Irgacure 819” manufactured by Ciba Japan Co., Ltd.) and 23 parts by mass of propylene glycol monomethyl ether acetate as an organic solvent for dilution were mixed with stirring. After pressure filtration using a polyflon filter having a pore size of 2 μm (“PF020” manufactured by Advantech Toyo Co., Ltd.), degassing was performed under reduced pressure to obtain a resin varnish for forming a cladding layer.
The resin composition for forming a clad layer obtained above was applied onto the non-treated surface of a PET film (“Cosmo Shine A4100” manufactured by Toyobo Co., Ltd., thickness 50 μm) using the coating machine. After drying at 20 ° C. for 20 minutes, a surface release treatment PET film (“Purex A31” manufactured by Teijin DuPont Films, Inc., thickness 25 μm) was applied as a protective film to obtain a resin film for forming a cladding layer. At this time, the thickness of the resin layer can be arbitrarily adjusted by adjusting the gap of the coating machine. In this embodiment, the thickness of the first lower cladding layer and the second lower cladding layer (adhesive layer) is used. Are described in the Examples. Moreover, the film thickness after hardening of the 1st lower clad layer and the 2nd lower clad layer and the film thickness after coating were the same. The film thickness of the upper clad layer forming resin film used in this example is also described in the examples. The film thickness of the upper clad layer forming resin film described in the examples is the film thickness after coating.

[Preparation of resin film for core layer formation]
(A) As a base polymer, 26 parts by mass of phenoxy resin (trade name: Phenototo YP-70, manufactured by Toto Kasei Co., Ltd.), (B) 9,9-bis [4- (2-acryloyl) as a photopolymerizable compound Oxyethoxy) phenyl] fluorene (trade name: A-BPEF, Shin-Nakamura Chemical Co., Ltd.) 36 parts by mass, and bisphenol A type epoxy acrylate (trade name: EA-1020, Shin-Nakamura Chemical Co., Ltd.) 36 mass Parts, (C) 1 part by mass of bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (trade name: Irgacure 819, manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, and 1- [4 -(2-Hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one (trade name: yl Cure 2959, manufactured by Ciba Specialty Chemicals) 1 part by weight, and using resin varnish B for forming a core layer under the same method and conditions as in the above production example, except that 40 parts by weight of propylene glycol monomethyl ether acetate was used as the organic solvent Prepared. Thereafter, pressure filtration and degassing under reduced pressure were performed under the same method and conditions as in the above production example.
The core layer-forming resin varnish B obtained above is applied to the non-treated surface of a PET film (trade name: Cosmo Shine A1517, manufactured by Toyobo Co., Ltd., thickness: 16 μm) in the same manner as in the above production example. After coating and drying, a release PET film (trade name: PUREX A31, Teijin DuPont Films Co., Ltd., thickness: 25 μm) is applied as a protective film so that the release surface is on the resin side, and a core layer forming resin A film was obtained. At this time, the thickness of the resin layer can be arbitrarily adjusted by adjusting the gap of the coating machine. In this example, the thickness of the resin film for forming the core layer used in this example is described in the following examples. Describe. The film thickness of the core layer forming resin film described in the examples is the film thickness after coating.

[Production of substrate]
(Electric wiring formation by subtractive method)
Polyimide film 101 with a single-sided copper foil as the metal layer 102 ((polyimide; Upilex VT (manufactured by Ube Nitto Kasei), thickness: 25 μm), (copper foil; NA-DFF (manufactured by Mitsui Kinzoku Mining Co., Ltd.)), thickness: 9 μm) A photosensitive dry film resist (trade name: Photec, manufactured by Hitachi Chemical Co., Ltd., thickness: 25 μm) is applied to the copper foil surface of FIGS. 1 (a) -1 and 2 (c) -1) with a roll laminator ( Hitachi Chemical Techno Plant Co., Ltd., HLM-1500) was applied under the conditions of pressure 0.4 MPa, temperature 110 ° C., laminating speed 0.4 m / min, and then an ultraviolet exposure machine (EXM-1172, manufactured by Oak Manufacturing Co., Ltd.). Exposed to ultraviolet light (wavelength 365 nm) at 120 mJ / cm ² from the photosensitive dry film resist side through a negative photomask with a width of 50 μm, and no dew The photosensitive portion of the photosensitive dry film resist was removed with a dilute solution of 0.1-5 wt% sodium carbonate at 35 ° C. Thereafter, using a ferric chloride solution, the exposed copper foil of the photosensitive dry film resist was removed by etching, and exposure was performed using a 1-10 wt% sodium hydroxide aqueous solution at 35 ° C. A portion of the photosensitive dry film resist was removed, and an electric wiring 103 having L (line width) / S (gap width) = 60/65 μm was formed to obtain a flexible wiring board.

(Formation of Ni / Au plating)
Thereafter, the flexible wiring board is degreased, soft etched, acid washed, immersed in an electroless Ni plating sensitizer (trade name: SA-100, manufactured by Hitachi Chemical Co., Ltd.) at 25 ° C. for 5 minutes, and then washed with water. It was immersed in an electroless Ni plating solution at 83 ° C. (manufactured by Okuno Pharmaceutical Co., Ltd., ICP Nicolon GM-SD solution, pH 4.6) for 8 minutes to form a 3 μm Ni film, and then washed with pure water.
Next, a substitution gold plating solution (100 mL; HGS-500 and 1.5 g; a bath with potassium gold cyanide / L) (trade name: HGS-500, manufactured by Hitachi Chemical Co., Ltd.) at 85 ° C. for 8 minutes. Immersion was performed to form a 0.06 μm displacement gold film on the Ni film. Thereby, the flexible wiring board by which the electrical wiring 103 part without a cover-lay film was coat | covered with plating of Ni and Au was obtained (refer Fig.1 (a) -2, FIG.2 (c) -2).
The 10 μm-thick clad layer-forming resin film obtained above as the adhesive layer 2 is cut into a size of 100 × 100 mm, the release PET film (Purex A31) as a protective film is peeled off, and the flexible film formed as described above A vacuum pressurization laminator (manufactured by Meiki Seisakusho Co., Ltd., MVLP-500) is used as a flat plate laminator on the polyimide surface of the wiring board, vacuumed to 500 Pa or less, pressure 0.4 MPa, temperature 100 ° C., pressurization time An electric wiring board with the second lower cladding layer 201 was formed by thermocompression bonding under a condition of 30 seconds. By irradiating 4 J / cm ^{2 of} ultraviolet rays (wavelength 365 nm) from the carrier film side with an ultraviolet exposure machine (EXM-1172, manufactured by Oak Manufacturing Co., Ltd.), then peeling the carrier film and heat-treating at 170 ° C. for 1 hour. Then, the substrate 1 with the second lower cladding layer 201 having a thickness of 10 μm was formed (see FIG. 1A-3 and FIG. 2C-3).

[Fabrication of optical fiber connector]
The 15 μm-thick lower clad layer-forming resin film obtained above is cut into a size of 100 × 100 μm, the protective film is peeled off, and a vacuum laminator is formed on the second lower clad layer 201 surface side under the same conditions as described above. Laminated. Through a negative photomask having 95 μm × 3.0 mm × 4 non-exposed portions, ultraviolet rays (wavelength 365 nm) were emitted from the carrier film side by an ultraviolet exposure machine (manufactured by Oak Manufacturing Co., Ltd., EXM-1172) at 250 mJ / Irradiated cm ² . Thereafter, the carrier film was peeled off, and the first lower cladding layer 3 was etched using a developer (1% potassium carbonate aqueous solution). Subsequently, the substrate was washed with water, heated and dried at 170 ° C. for 1 hour, and cured to produce a substrate 1 with a first lower cladding layer 3 in which an opening of 95 μm × 3.0 mm was formed in the optical fiber groove forming part (FIG. 1 (a) -4, FIG. 2 (c) -4, FIG. 2 (d) -4). As a result, the first lower cladding layer 3 is formed in the portion where the optical waveguide 20 is formed, and the first lower cladding layer 3 is not present in the groove 8 portion where the optical fiber is mounted.
Next, a roll laminator (manufactured by Hitachi Chemical Technoplant Co., Ltd., HLM-1500) is used on the surface of the first lower clad layer 3, and the pressure is 0.4 MPa, the temperature is 50 ° C., and the lamination speed is 0.2 m / min. After laminating the resin film for forming a core layer having a thickness of 50 μm from which the protective film has been peeled off, and then vacuuming to 500 Pa or less using the above-described vacuum pressure laminator (manufactured by Meiki Seisakusho Co., Ltd., MVLP-500), pressure Thermocompression bonding was performed under the conditions of 0.4 MPa, a temperature of 70 ° C., and a pressing time of 30 seconds. Then, optical signal transmission core pattern width 50 μm (pattern pitch of optical fiber connection portion: 125 μm, pattern pitch of optical path conversion mirror forming portion (5 mm point from optical fiber connection portion); 250 μm, 4), core pattern for fiber guide The optical signal transmission core pattern 4 is formed on the first lower cladding layer 3 on the first lower clad layer 3 through a negative photomask having a width of 40 μm (fiber groove pitch: 125 μm, four, and fiber guide core patterns at both ends only 150 μm). Alignment is performed so that the groove 8 formed by the core pattern 5 is formed on the substrate 1 (second lower clad layer 201), and ultraviolet rays (wavelength 365 nm) are irradiated with 700 mJ / cm ² by the ultraviolet exposure machine. Subsequently, post-exposure heating was performed at 80 ° C. for 5 minutes.

Here, the optical fiber insertion side guide width b of the fiber guide core pattern 5 shown in FIGS. 4A and 4B is determined by the pitch dimension of the optical fiber 30 when the optical fiber 30 is mounted in a multi-core configuration. For example, in the case of a 250 μm pitch, if the minimum guide width dimension is considered at a fiber diameter of 80 μm, the guide width b needs to be 250 μm or less calculated by (pitch dimension−fiber diameter) + fiber diameter. When mounting the optical fiber 30 as a single core, it is better to take the guide width b as wide as possible, but it is easier to insert the optical fiber 30 without resistance if it is within the range of 1.5 to 3.5 times the fiber diameter. .
Thereafter, the PET film as the carrier film was peeled off, and the core pattern was etched using a developer (propylene glycol monomethyl ether acetate / N, N-dimethylacetamide = 8/2, mass ratio). Subsequently, the substrate was washed with a cleaning solution (isopropanol), dried by heating at 100 ° C. for 10 minutes to form an optical signal transmission core pattern 4 and a fiber guide core pattern 5, and at the same time, a groove 8 having a width of 85 μm was formed. . The size of each pattern in the fiber guide core pattern 5 is such that when the optical fiber is fixed in the groove 8, the optical fiber is bonded to the optical signal transmitting core pattern 4 at a position where an optical signal can be transmitted and received. It is designed (see FIG. 1 (a) -5, FIG. 1 (b) -5, FIG. 2 (c) -5, FIG. 2 (d) -5, FIG. 3 (e)).

Next, after the upper cladding layer resin film having a thickness of 85 μm from which the protective film has been peeled is evacuated to 500 Pa or less using the above-described vacuum pressure laminator (MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.) from the core pattern forming surface side. The film was laminated by thermocompression bonding under the conditions of a pressure of 0.4 MPa, a temperature of 110 ° C., and a pressing time of 30 seconds. Further, after irradiating 150 J / cm ^{2 of} ultraviolet rays (wavelength 365 nm) using the negative photomask used in forming the first lower cladding layer 3, the carrier film was peeled off, and a developer (1% potassium carbonate aqueous solution) Was used to etch the upper clad layer forming resin film in the groove 8 portion. Subsequently, it was washed with water, dried and cured at 170 ° C. for 1 hour.
As described above, an optical fiber connector for 125 μm pitch, fiber diameter of 80 μm, and 4 channels was produced.
In the obtained optical fiber connector, the lateral width a of the joint between the optical fiber 30 and the optical waveguide 20 in the groove 8 of the fiber guide core pattern 5 was 85 μm, and the lateral width (guide width) b of the opposite end was 120 μm. (See FIG. 4). The height of the fiber guide core pattern 5 (height from the surface of the second lower cladding layer 201) is 64 μm, the height from the substrate surface to the upper surface of the upper cladding layer is 85.5 μm, and the thickness of the optical signal transmission core pattern 4 Was 50 μm (see FIG. 1 (a) -6, FIG. 1 (b) -6, FIG. 2 (c) -6, FIG. 2 (d) -6).

(Slit groove formation)
In order to smooth the optical fiber connection end face of the obtained optical waveguide 20, a slit groove 9 having a width of 40 μm was formed using a dicing saw (DAC552, manufactured by Disco Corporation) (FIG. 1 (a) -7, FIG. 1 (b) -7). At the same time, the substrate was cut in parallel to the fiber guide core pattern (3 mm from the end face of the optical waveguide), and the outer shape was processed so that the groove 8 for mounting the optical fiber appeared on the end face of the substrate.
(Formation of optical path conversion mirror)
A 45 ° optical path conversion mirror 11 was formed using a dicing saw (DAC552, manufactured by Disco Corporation) from the upper clad layer 6 side of the obtained optical waveguide 20 (FIGS. 1A-7 and 1B). ) -7). Next, a metal mask having an opening in the mirror formation portion was placed on an optical fiber connector with a mirror, and Au was vapor-deposited by 0.5 μm as a vapor-deposited metal layer 12 using a vapor deposition apparatus (RE-0025, manufactured by First Giken) (FIG. 1 (a) -8, see FIG. 1 (b) -8).

(Cover material formation)
Thereafter, the protective film of the 10 μm-thick clad layer forming resin film obtained above as a lid adhesive layer 701 on the polyimide film (Upilex RN (manufactured by Ube Nitto Kasei), thickness: 25 μm) is peeled off, and Were laminated by a vacuum laminator under the same conditions as above to form a lid member 7 with an adhesive layer 701 (FIGS. 1 (a) -9, 1 (b) -9, 2 (c) -7, 2 (See (d) -7). Next, the carrier film of the clad layer forming resin film laminated on the lid member 7 is peeled off, and heat-pressed with a vacuum laminator under the same conditions as above from the upper clad layer 6 forming surface side of the optical fiber connector. . Subsequently, the optical fiber connector with the cover material 7 was formed by heating and curing at 180 ° C. for 1 h. The height from the surface of the substrate 1 (second lower cladding layer 201) of the groove 8 for mounting an optical fiber to the bottom surface of the lid member 7 (bottom surface of the adhesive layer 701 of the lid member) was 82 μm.
The optical fiber 30 (core diameter: 50 μm, clad diameter: 80 μm) having a 125 μm pitch and 4 channels is inserted into the space formed by the groove 8 and the cover material 7 of the optical fiber connector obtained as described above. It can be easily inserted and bonded to the optical transmission surface of the optical signal transmission core pattern 5 of the optical waveguide 20 so that the optical signal can be transmitted from the optical fiber 30 and the optical fiber 30 is displaced. There was not.

As described above in detail, the optical fiber connector of the present invention is easy to attach an optical fiber regardless of the substrate, easy to align the optical fiber and the optical waveguide core, and hardly misaligns the optical fiber. In addition, the optical fiber and the optical waveguide can be easily coupled simply by inserting the optical fiber into the space formed by the groove and the lid member.
Therefore, it is useful as a photoelectric conversion substrate for optical fibers.

1. Substrate 101. Polyimide film 102. Metal layer 103. Metal wiring, electrical wiring Adhesive layer 201. Lower cladding layer (second lower cladding layer)
3. Lower cladding layer (first lower cladding layer)
4). 4. Optical signal transmission core pattern 5. Core pattern for fiber guide 6. Upper clad layer Lid 701. 7. Adhesive layer (for lid material) Groove (fiber groove)
9. Slit groove 10. 10. Optical fiber guide member Optical path conversion mirror 12. Deposition metal layer 20. Optical waveguide 30. Optical fiber

Claims (12)

An optical fiber guide member in which a core pattern for fiber guide having a fiber groove for fixing an optical fiber is formed on a substrate;
An optical signal transmission core pattern is formed on the first lower clad layer, and an optical waveguide having an upper clad layer formed on the optical signal transmission core pattern is provided in parallel.
The fiber groove is inserted into the fiber groove from the side opposite to the optical waveguide so that the optical fiber is bonded to a position where an optical signal can be transmitted to the optical signal transmission core pattern of the optical waveguide. An optical fiber connector for guiding an end of an optical fiber to the optical waveguide,
The width of the fiber groove is larger from the optical fiber and the optical waveguide side joint toward the opposite side,
The optical signal transmission core pattern and the fiber guide core pattern are formed together,
The portion of the fiber guide core pattern exposed on the side surface of the fiber groove extends to the upper surface of the substrate while being exposed so as to be in contact with the optical fiber inserted into the fiber groove .
An optical fiber connector in which a flexible lid is formed to cover the upper cladding layer on the fiber guiding core pattern of the fiber guiding core pattern and the upper cladding layer . The optical fiber connector according to claim 1, wherein the lid member is polyamideimide or polyimide. The optical fiber connector according to claim 1, wherein the lid member has an adhesive layer on a surface on a side where a groove for fixing the optical fiber is provided. The optical signal transmitting core pattern is formed on the first lower cladding layer formed on said substrate, said fiber guide core pattern was formed on the substrate, any one of claims 1 to 3 An optical fiber connector as described in 1. 5. The optical fiber connector according to claim 1 , wherein the substrate has an adhesive layer, and the first lower cladding layer and the fiber guide core pattern are formed on the adhesive layer of the substrate . The optical fiber connector according to claim 5 , wherein the adhesive layer of the substrate is a second lower cladding layer. 6. The optical fiber connector according to claim 1 , further comprising an upper clad layer on the fiber guide core pattern. The optical fiber connector according to any one of claims 1 to 7 , wherein the optical waveguide of the optical fiber connector is an optical waveguide with an optical path conversion mirror, and the lid member functions as a reinforcing material for the optical path conversion mirror. . The optical fiber connector according to claim 1 , wherein the substrate is an electric wiring board. A method of manufacturing an optical fiber connector according to any one of claims 1 to 9 ,
A first lower clad layer forming film is laminated on the substrate, and the first lower clad layer forming film is etched to remove the first lower clad layer forming film at a portion where the fiber groove is to be formed. The process of
A core forming film is laminated on the first lower clad layer and the substrate from which the first lower clad layer forming film has been removed in the first step, and then etched to form the optical signal transmission core pattern. A second step of collectively forming a fiber guide core pattern so that the fiber groove is formed;
A third step of sequentially forming the lid material so as to cover the upper cladding layer on the fiber guide core pattern of the fiber guide core pattern and the upper cladding layer ;
The fiber groove guides the end of the optical fiber inserted into the fiber groove from the side opposite to the optical waveguide to the optical waveguide,
Forming the fiber guide core pattern so that the groove of the fiber groove becomes larger toward the opposite side from the joint where the optical fiber and the optical waveguide side are joined;
A method of manufacturing an optical fiber connector, wherein a portion of the fiber guide core pattern exposed to the side surface of the fiber groove extends to the upper surface of the substrate. Wherein between the second step and the third step, from said fiber guide core pattern the optical signal transmitting core pattern formation surface side and laminating the upper cladding layer-forming film, by etching, the fiber groove The method of manufacturing an optical fiber connector according to claim 10, further comprising a fourth step of removing the upper clad layer forming film in the portion.   A fifth step of forming a slit groove by a dicing saw immediately before or after the fourth step is characterized in that the depth of the slit groove is equal to or less than the surface of the first lower cladding layer. Item 12. A method for producing an optical fiber connector according to Item 10 or 11.

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