JP2011221195A - Optical waveguide structure and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical waveguide structure and an electronic device which have a high degree of freedom for designing a pattern shape, which enable the formation of a core portion (optical path) having high dimensional accuracy by a simple method, and which include an optical waveguide having high optical coupling efficiency with light-emitting and light-receiving elements and is excellent in durability.SOLUTION: An optical waveguide structure includes an optical waveguide 9 which is configured such that a core layer 93 and cladding layers 91 and 92 are laminated. The core layer 93 includes a core portion 94 and a cladding portion 95. The core portion 94 has a broad portion 941 in which a width of the core portion 94 is gradually wider toward one end and a narrow portion 942 in which a width of the core portion 94 is gradually narrower toward the other end. The core portion 94 is formed by selectively irradiating light on the core layer 93 comprising a composition including: (A) cyclic olefin resin; (B) at least one of a monomer and an oligomer having cyclic ether group, which are different in refractive index from (A); and (C) a photoacid generator.

Description

  The present invention relates to an optical waveguide structure and an electronic device.

  In recent years, optical branching couplers (optical couplers), optical multiplexers / demultiplexers, and the like have been developed as optical components in the field of optical communications, and optical waveguide devices used for these are promising. As this optical waveguide type element (hereinafter, also simply referred to as “optical waveguide”), there are polymer optical waveguides that are easy to manufacture (patterning) and are versatile, in addition to conventional quartz optical waveguides. Is being actively developed.

  Such an optical waveguide is usually formed in a predetermined arrangement (pattern) on a substrate and handled as an optical waveguide structure. As this optical waveguide structure, a structure in which a predetermined electric wiring circuit and an optical waveguide composed of a core portion and a cladding portion are formed on a substrate, and a light emitting element and a light receiving element are attached to the optical waveguide is disclosed. (For example, refer to Patent Document 1).

However, the optical waveguide structure described in Patent Document 1 has the following problems.
1. The process of forming the optical waveguide is complicated, and the degree of freedom in designing and selecting the pattern shape of the core part constituting the optical path of the transmitted light is narrow.
2. The core pattern shape accuracy and dimensional accuracy are poor.
3. Optical signal transmission efficiency is low.
4). When combined with an electrical wiring pattern, the degree of freedom in designing the electrical wiring pattern is narrow.

JP 2004-146602 A

  An object of the present invention is to form a core part (optical path) with a wide degree of freedom in design of a pattern shape and high dimensional accuracy by a simple method, and also to optical coupling efficiency and durability with a light emitting element and a light receiving element. An object of the present invention is to provide an optical waveguide structure and an electronic device including an optical waveguide having excellent properties.

Such an object is achieved by the present inventions (1) to (34) below.
(1) having an optical waveguide provided with a core part and a clad part having different refractive indexes,
The core portion has an extended portion whose cross-sectional area continuously increases toward one end portion, and
(A) a cyclic olefin resin;
(B) The refractive index is different from that of (A), and at least one of a monomer having a cyclic ether group and an oligomer having a cyclic ether group;
(C) a photoacid generator;
An optical waveguide structure characterized by being formed into a desired shape by selectively irradiating active radiation to a core layer composed of a composition comprising:

  (2) The optical waveguide structure according to (1), wherein the cyclic ether group of (B) is an oxetanyl group or an epoxy group.

  (3) The optical waveguide structure according to (1) or (2), wherein the cyclic olefin resin (A) is a norbornene resin.

(4) The refractive index of (B) is lower than that of (A),
(1) The cyclic olefin resin has a leaving group that is desorbed by an acid generated from the photoacid generator of (C) and lowers the refractive index of (A) by desorption. Thru | or the optical waveguide structure in any one of (3).

(5) The cyclic olefin resin of (A) has a leaving group that is eliminated by an acid generated from the photoacid generator of (C) in the side chain,
Said (B) is an optical waveguide structure as described in said (2) containing the 1st monomer as described in following formula (100).

  (6) The optical waveguide structure according to (5), wherein (B) further includes at least one of the epoxy compound and the oxetane compound having two oxetanyl groups as the second monomer.

  (7) The ratio of the second monomer to the first monomer is 0.1 to 1.0 in a weight ratio (weight of the second monomer / weight of the first monomer). The optical waveguide structure described.

  (8) The leaving group may have at least one of an -O- structure, an -Si-aryl structure, and an -O-Si- structure. The optical waveguide structure described.

  (9) The optical waveguide structure according to any one of (5) to (8), wherein the cyclic olefin resin of (A) is a norbornene resin.

  (10) The optical waveguide structure according to (9), wherein the norbornene-based resin is a norbornene addition polymer.

［式中のｎは、０以上９以下の整数である。］ (11) The optical waveguide structure according to (10), wherein the norbornene addition polymer has a repeating unit represented by the following formula (101).

[N in the formula is an integer of 0 or more and 9 or less. ]

(12) The optical waveguide structure according to (10) or (11), wherein the norbornene addition polymer has a repeating unit represented by the following formula (102).

  (13) The content of the first monomer described in the formula (100) is 1 part by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the cyclic olefin resin. An optical waveguide structure according to claim 1.

  (14) The light according to any one of (1) to (13), wherein the concentration of the structure derived from (B) is different between a region irradiated with active radiation of the core layer and a non-irradiated region. Waveguide structure.

  (15) The optical waveguide structure according to any one of (1) to (14), wherein the refractive index difference between the region irradiated with active radiation and the non-irradiated region of the core layer is 0.01 or more.

  (16) The structure according to any one of (1) to (15), wherein the region of the core layer that has been irradiated with active radiation is at least a part of the cladding part, and an unirradiated region is at least a part of the core part. Optical waveguide structure.

  (17) The expansion portion according to any one of (1) to (16), wherein a width of the core portion in plan view continuously increases toward one end of the optical waveguide. Optical waveguide structure.

  (18) The optical waveguide according to any one of (1) to (17), wherein the thickness of the core portion is continuously increased toward one end of the optical waveguide in the extended portion. Structure.

  (19) In the extended portion, the core portion is formed such that a boundary line between the core portion and the cladding portion in plan view is along a parabola that opens toward one end portion of the optical waveguide. The optical waveguide structure according to any one of (1) to (18) above.

  (20) In the extended portion, the core portion may have a boundary line between the core portion and the cladding portion in a plan view or a boundary line between the core portion and the cladding portion in the thickness direction. The optical waveguide structure according to any one of (1) to (19), wherein an angle of 45 degrees or more and less than 90 degrees is formed with respect to an end face of one end portion.

  (21) The optical waveguide structure according to any one of (1) to (20), wherein an area of an end face of the one end is larger than an area of an end face of the other end. body.

  (22) The width in plan view of the one endmost part of the core part is larger than the width in plan view of the other endmost part. Optical waveguide structure.

  (23) The optical waveguide structure according to any one of (1) to (22), wherein a thickness of the one endmost portion of the core portion is greater than a thickness of the other endmost portion.

  (24) The core portion further includes a reduced portion that is provided on the other end side with respect to the extended portion and that has a reduced cross-sectional area continuously decreasing toward the other end portion. (23) The optical waveguide structure according to any one of (23).

  (25) The optical waveguide structure according to (24), wherein in the reduced portion, the width of the core portion in plan view continuously decreases toward the other end of the optical waveguide.

  (26) The optical waveguide structure according to (24) or (25), wherein in the reduced portion, the thickness of the core portion is continuously reduced toward the other end of the optical waveguide.

  (27) In the reduced portion, the core portion is formed such that a boundary line between the core portion and the clad portion in plan view is along a parabola that opens toward one end portion of the optical waveguide. The optical waveguide structure according to any one of (24) to (26) above.

  (28) In the reduced portion, the core portion may have a boundary line between the core portion and the cladding portion in a plan view or a boundary line between the core portion and the cladding portion in the thickness direction. The optical waveguide structure according to any one of (24) to (27), wherein an angle of 45 degrees or more and less than 90 degrees is formed with respect to an end face of one end portion.

  (29) The optical waveguide structure according to any one of (1) to (28), wherein the optical waveguide includes a plurality of the core portions.

(30) The plurality of core portions are provided in parallel,
The optical waveguide structure according to (29), wherein at least two of the plurality of core portions adjacent to each other have at least one of a position of one end and a position of the other end shifted in the longitudinal direction. body.

  (31) In the at least two adjacent cores, the position of the one end and the position of the other end are configured to be opposite to each other ( The optical waveguide structure according to 29) or (30).

(32) The optical waveguide has an optical path conversion unit that bends the optical path,
The optical path conversion unit is configured to bend light from the outside and guide it to the core part, or to bend and guide the light propagating through the core part to the outside (1) to (31) An optical waveguide structure according to claim 1.

  (33) The above (1) further including a wiring board provided on at least one surface of the optical waveguide and including a substrate and a conductor layer provided on at least one surface of the optical waveguide and provided with electrical wiring. ) To (32).

  (34) An electronic apparatus comprising the optical waveguide structure according to any one of (1) to (33).

  According to the present invention, the core portion can be patterned by a simple method of light irradiation, and the core portion having a wide degree of freedom in designing the pattern shape of the core portion and high dimensional accuracy can be obtained.

  Moreover, since the dimensional accuracy of the core portion is high, an optical waveguide having excellent optical coupling efficiency with respect to the light emitting element and the light receiving element can be obtained.

  In addition, when the core part is composed of a resin composition mainly composed of norbornene resin (cyclic olefin resin), the effect of being particularly strong against deformation and being difficult to cause defects is high, and the core part and the clad part The difference in refractive index can be further increased, and the optical waveguide is excellent in heat resistance. As a result, an optical waveguide having higher performance and excellent durability can be obtained.

  In addition, both electric circuits and optical circuits can be easily formed, and various shapes can be formed with high dimensional accuracy. In particular, the optical circuit can be formed with any shape and arrangement of the optical path (core part) by selecting the exposure pattern, and it can be sharply formed even with a thin optical path. This contributes to reducing the size of the device.

  Such an optical waveguide structure of the present invention has a wide range of optical circuit (optical waveguide pattern) and electrical circuit design, high yield, high optical transmission performance, excellent reliability and durability, Rich in versatility. Therefore, by providing the optical waveguide structure of the present invention, various highly reliable electronic parts and electronic devices can be obtained.

It is sectional drawing which shows 1st Embodiment of the optical waveguide structure of this invention. It is a perspective view of the optical waveguide shown in FIG. It is a top view which shows the core layer of the optical waveguide shown in FIG. It is a top view which shows the core layer of 2nd Embodiment of the optical waveguide structure of this invention. It is sectional drawing which shows 3rd Embodiment of the optical waveguide structure of this invention. It is sectional drawing which shows 4th Embodiment of the optical waveguide structure of this invention. It is sectional drawing which shows 5th Embodiment of the optical waveguide structure of this invention. It is a top view which shows the core layer of 5th Embodiment of the optical waveguide structure of this invention. It is a top view which shows the core layer of 6th Embodiment of the optical waveguide structure of this invention. It is a top view which shows 6th Embodiment of the optical waveguide structure of this invention. It is sectional drawing which shows typically the process example of the 1st manufacturing method of an optical waveguide. It is sectional drawing which shows typically the process example of the 1st manufacturing method of an optical waveguide. It is sectional drawing which shows typically the process example of the 1st manufacturing method of an optical waveguide. It is a perspective view which shows typically the example of a process of the 2nd manufacturing method of an optical waveguide. It is a perspective view which shows typically the example of a process of the 2nd manufacturing method of an optical waveguide. It is a perspective view which shows typically the example of a process of the 2nd manufacturing method of an optical waveguide. It is a figure which shows typically the measuring method of the bending loss in an Example.

  Hereinafter, the optical waveguide structure and electronic device of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<First embodiment: FIGS. 1 to 3>
1 is a sectional view showing a first embodiment of the optical waveguide structure of the present invention, FIG. 2 is a perspective view of the optical waveguide shown in FIG. 1, and FIG. 3 shows a core layer of the optical waveguide shown in FIG. It is a top view. In the following description, the upper side in FIG. 1 is “upper” and the lower side is “lower”. 1 and 2 are exaggerated in the layer thickness direction (vertical direction in each figure).

  As shown in FIG. 1, an optical waveguide structure 1 of the present invention includes a substrate 2, a conductor layer 5 provided on the lower surface of the substrate 2, a light emitting element 3 and a light receiving element 4 provided on the substrate 2, An optical waveguide 9 provided between the light emitting part 31 of the light emitting element 3 and the light receiving part 41 of the light receiving element 4 is provided. The board 2 and the conductor layer 5 constitute a wiring board.

  The optical waveguide 9 is a belt-like structure in which a clad layer (lower clad layer) 91, a core layer 93, and a clad layer (upper clad layer) 92 are laminated in this order from the lower side in FIG. Are formed with a core portion 94 and a clad portion 95 having a predetermined long and narrow pattern set along the longitudinal direction of the optical waveguide 9 having a strip shape. The core portion 94 is a portion that forms an optical path of the transmission light, and the cladding portion 95 does not form an optical path of the transmission light although it is formed in the core layer 93 and performs the same function as the cladding layers 91 and 92. Part.

  As a constituent material of the core layer 93, a material whose refractive index changes by irradiation with light (for example, ultraviolet rays) or by further heating is used. Preferable examples of such materials include those containing a resin composition containing a cyclic olefin resin such as a benzocyclobutene polymer and a norbornene polymer (resin) as a main material, and include a norbornene polymer (mainly The material) is particularly preferred.

  The core layer 93 made of such a material is excellent in resistance to deformation such as bending, and even when it is repeatedly curved and deformed, the core layer 94 and the clad portion 95 are separated from each other, and the layer adjacent to the core layer 93 ( The delamination with the clad layers 91 and 92) hardly occurs, and the occurrence of microcracks in the core portion 94 and the clad portion 95 is also prevented. As a result, the optical transmission performance of the optical waveguide 9 is maintained, and the optical waveguide 9 having excellent durability is obtained.

  Examples of the constituent material of the core layer 93 include an antioxidant, a refractive index adjuster, a plasticizer, a thickener, a reinforcing agent, a sensitizer, a leveling agent, an antifoaming agent, an adhesion aid, and a flame retardant. The additive may be contained. Addition of an antioxidant has the effect of improving high temperature stability, improving weather resistance, and suppressing light deterioration. Examples of such an antioxidant include phenols such as monophenols, bisphenols, and triphenols, and aromatic amines. Further, the resistance to bending can be further increased by adding a plasticizer, a thickener, and a reinforcing agent.

  The content of additives typified by the antioxidant (the total in the case of two or more) is preferably about 0.5 to 40% by weight, and 3 to 30% by weight with respect to the entire constituent material of the core layer 93. The degree is more preferable. If this amount is too small, the function of the additive cannot be sufficiently exhibited. If the amount is too large, the transmittance of light (transmitted light) transmitted through the core portion 94 depends on the type and characteristics of the additive. Decrease, patterning failure, refractive index instability and the like.

  An example of a method for forming the core layer 93 is a coating method. Examples of the coating method include a method in which a core layer forming composition (varnish or the like) is applied and cured (solidified), and a method in which a curable monomer composition is applied and cured (solidified). In addition, a method other than the coating method, for example, a method of joining separately manufactured sheet materials may be employed.

  The core layer 93 obtained as described above is selectively irradiated with light (active radiation) using a mask to pattern the core portion 94 having a desired shape.

  Examples of light used for exposure include active energy rays such as visible light, ultraviolet light, infrared light, and laser light. Further, instead of using light, electromagnetic waves such as X-rays or particle beams such as electron beams may be used.

  In the core layer 93, the portion irradiated with light has a lower refractive index, and a difference in refractive index occurs between the portion not irradiated with light. For example, a portion of the core layer 93 that is irradiated with light becomes the cladding portion 95, and a portion that is not irradiated becomes the core portion 94. The refractive index of the cladding part 95 is substantially equal to the refractive index of the cladding layers 91 and 92.

  Moreover, the core part 94 may be formed by irradiating the core layer 93 with light in a predetermined pattern and then heating. By adding this heating step, the difference in refractive index between the core portion 94 and the cladding portion 95 becomes larger, which is preferable. This principle will be described later in detail.

  As shown in FIG. 2, the pattern shape of the core portion 94 formed is a widened portion (expanded portion) 941 whose width continuously increases toward the left end portion (one end portion in the longitudinal direction), A reduced width portion (reduced portion) 942 whose width continuously decreases toward the right end portion (the other end portion in the longitudinal direction), and is provided between the widened portion 941 and the reduced width portion 942. It is composed of a uniform width portion 940 having a constant width. On the other hand, the core layer 93 in which the core portion 94 is formed has a constant thickness as shown in FIG. Accordingly, the widened portion 941 shown in FIG. 2 is a portion in which the cross-sectional area of the core portion 94 continuously increases toward the left end portion, and the reduced width portion 942 is the core toward the right end portion. This is a portion where the cross-sectional area of the portion 94 is continuously reduced. Furthermore, the equal width portion 940 is a portion where the cross-sectional area of the core portion 94 is constant.

  The pattern shape of the core portion 94 is a shape having a curved portion, a shape having a branching portion, a merging portion or a crossing portion, or a combination of two or more of these, in addition to the widened portion 941 and the reduced width portion 942 described above. Any shape may be used. In the formation of these patterns, the feature of the present invention is that any pattern shape can be easily realized by setting the light irradiation pattern.

  The constituent material of each part of the optical waveguide 9 and the method of forming the core part 94 will be described in detail later.

The substrate 2 is a flexible substrate having flexibility and insulation.
Examples of the constituent material of the substrate 2 include epoxy resin, phenol resin, bismaleimide resin, bismaleimide / triazine resin, triazole resin, polycyanurate resin, polyisocyanurate resin, benzocyclobutene resin, polyimide resin, and polybenzoxazole. Examples thereof include resins and norbornene resins. These materials may be used alone or in combination.

  Moreover, the board | substrate 2 may be a laminated body of a some layer. For example, a first layer and a second layer made of a resin material having the same composition (kind) are laminated, and a first layer and a second layer made of resin materials having different compositions (kinds) are laminated. The thing which was done is mentioned. In addition, it cannot be overemphasized that the layer structure in a laminated body is not limited to this.

  Although the thickness of the board | substrate 2 is not specifically limited, Usually, it is preferable that it is about 5-50 micrometers, and it is more preferable that it is about 10-40 micrometers. If the thickness of the substrate 2 is within the above range, the optical waveguide structure 1 has sufficient flexibility.

  The flexibility of the substrate 2 is, for example, such that it can be easily bent by a human hand. Specifically, the Young's modulus (tensile modulus) of the substrate 2 is preferably about 1 to 20 GPa and more preferably about 2 to 12 GPa in a general room temperature environment (around 20 to 25 ° C.). preferable.

  Each of the conductor layers 5 bonded to the lower surface of the substrate 2 is patterned into a predetermined shape to constitute a desired wiring or circuit. Examples of the constituent material of the conductor layer 5 include various metal materials such as copper, a copper-based alloy, aluminum, and an aluminum-based alloy. Although the thickness of the conductor layer 5 is not specifically limited, Usually, about 3-120 micrometers is preferable and about 5-70 micrometers is more preferable.

  The conductor layer 5 is formed, for example, by a method such as metal foil bonding (adhesion), metal plating, vapor deposition, or sputtering. For patterning on the conductor layer 5, for example, methods such as etching, printing, masking, etc. can be used.

  On the other hand, a through hole 21 is formed in the substrate 2, and the through hole 21 is filled with a conductive material (for example, various metal materials such as copper, copper alloy, aluminum, aluminum alloy, etc.), and a conductor post. 22 is provided. The conductor post 22 electrically connects the conductor layer 5 and the upper surface side of the substrate 2.

  The light emitting element 3 includes a base 30, a light emitting unit 31 fixed to the surface of the base 30, a metal wire 32 connecting the electrode pad of the light emitting unit 31 and the electrode pad of the base 30, An external electrode 33 is provided on the lower surface for connecting the light emitting unit 31 to an external circuit. The light emitting unit 31 and the metal wire 32 are covered with a resin mold 34 hemispherically stacked on the surface of the base 30.

When the external electrode 33 is energized, the light emitting unit 31 emits light.
The light emitting element 3 is mounted on the substrate 2 such that the external electrode 33 is joined (electrically connected) to the conductor post 22.

  On the other hand, the light receiving element 4 includes a base 40, a light receiving part 41 fixed to the surface of the base 40, a metal wire 42 connecting the electrode pad of the light receiving part 41 and the electrode pad of the base 40, and a base 40, and has an external electrode 43 for connecting the light receiving unit 41 to an external circuit. Further, the light receiving portion 41 and the metal wire 42 are covered with a resin mold 44 hemispherically stacked on the surface of the base 40.

  When the light receiving unit 41 receives an optical signal, it is converted into an electric signal and output from the external electrode 43.

  The light receiving element 4 is mounted on the substrate 2 such that the external electrode 43 is joined (electrically connected) to the conductor post 22.

  The light emitting unit 31 in the light emitting element 3 and the light receiving unit 41 in the light receiving element 4 may each be composed of one light emitting point or one light receiving point, or may be a group of a plurality of light emitting points or light receiving points. . As a collection of a plurality of light emitting points or light receiving points, for example, light emitting points or light receiving points are arranged in a row (for example, 1 × 4 light emitting points or 1 × 12 light emitting points or light receiving points) or a matrix (for example, light emitting points or light receiving points). Examples include n × m light receiving points: n and m are integers of 2 or more, and a plurality of light emitting points or light receiving points arranged randomly (irregularly).

  The resin mold 34 seals the light emitting unit 31 and the like on the right side of the base 30 of the light emitting element 3. Thereby, since the light emitting unit 31 is sealed without being exposed to the outside, the light emitting unit 31 is protected from dirt, damage, oxidation, and the like. As a result, the reliability of the light emitting element 3 is improved.

  The resin mold 44 seals the light receiving portion 41 and the like on the left side of the base 40 of the light receiving element 4. As a result, the light receiving portion 41 is sealed without being exposed to the outside, so that the light receiving portion 41 is protected from dirt, damage, oxidation, and the like. As a result, the reliability of the light receiving element 4 is improved.

  Moreover, as a constituent material of the resin molds 34 and 44, an insulating resin material is preferable, and examples thereof include an epoxy resin, a phenol resin, a norbornene resin, and a silicon resin.

  The optical waveguide 9 is provided between the light emitting element 3 and the light receiving element 4 so as to connect the light emitting point of the light emitting unit 31 and the light receiving point of the light receiving unit 41. Thereby, the light emitting point and the light receiving point are optically connected by the optical waveguide 9.

  The core portion 94 of the optical waveguide 9 is formed in a pattern shape that overlaps each light emitting point and each light receiving point in a plan view (when viewed from above in FIG. 1). The core portion 94 has a higher refractive index than that of the cladding portion 95 and has a higher refractive index than the cladding layers 91 and 92. The clad layers 91 and 92 constitute the clad portions located at the lower part and the upper part of the core part 94, respectively. With such a configuration, as shown in FIG. 2, the core portion 94 functions as a light guide path surrounded by the clad portion on the entire outer periphery.

  Both end portions of the optical waveguide 9 (connection portions between the light emitting element 3 and the light receiving element 4) are covered with a resin mold 34 provided on the light emitting element 3 and a resin mold 44 provided on the light receiving element 4. 3 and the light receiving element 4. Thereby, the optical waveguide 9, the light emitting element 3, and the light receiving element 4 are integrated and can be handled as one component (optical wiring).

  The optical waveguide 9 shown in FIG. 2 has one core portion 94, but the number of core portions 94 formed in one optical waveguide 9 is, for example, light emission provided in one light emitting portion 31. It is set according to the number of points and the number of light receiving points provided in one light receiving unit 41 and is not particularly limited.

  In the optical waveguide structure 1 of the present embodiment, when the external electrode 33 of the light emitting element 3 is energized through the conductor layer 5 and the conductor post 22, the light emitting point of the light emitting portion 31 emits light, and the right side in FIG. The light emitted toward the light enters the core portion 94 of the optical waveguide 9. The optical waveguide 9 repeats reflection at the interface between the core portion 94 and the clad portion (the clad layers 91 and 92 and the side clad portion 95), and the inside of the core portion 94 is in the longitudinal direction (right direction in FIG. 1). Proceed along. When the light reaches the light receiving point of the light receiving unit 41, the light signal is converted into an electric signal in the light receiving unit 41 and output from the external electrode 43.

  Although such an optical waveguide structure 1 will be described in detail later, since the optical waveguide 9 is made of a polymer material, the optical waveguide structure 1 is flexible and has a difference in refractive index between the core portion 94 and the cladding portion 95. Therefore, even when the optical waveguide 9 is bent, the transmission efficiency is sufficient.

  Further, since the optical waveguide 9 and the substrate 2 are not directly fixed, the optical waveguide 9 and the substrate 2 can freely move when a bending operation is performed. Then, local stress concentration is prevented, and the optical waveguide 9 can be prevented from being broken due to the bending operation. As a result, the optical waveguide structure 1 having excellent durability can be obtained.

  Here, the optical waveguide 9 of the optical waveguide structure 1 includes a widened portion 941 in which the width of the core portion 94 continuously increases toward the left end portion in plan view, and the width of the core portion 94 on the right side. It has a reduced width portion 942 that continuously decreases toward the end.

  In the widened portion 941 shown in FIG. 3A, the width continuously increases toward the left end portion at a constant rate. Further, in the reduced width portion 942 shown in FIG. 3A, the width continuously decreases toward the right end portion at a constant rate.

  As shown in FIG. 1, by arranging the light emitting point of the light emitting element 3 so as to face the left end face of the widened portion 941, light can be incident on the widened portion 941 with high efficiency. That is, since the area of the left end face of the widened portion 941 is larger than that of the right end face, light emitted from the light emitting point can be received efficiently. In particular, when a semiconductor laser is used as the light emitting element 3, since light is emitted with a predetermined spread angle, the area of the left end face of the widened portion 941 is large, so that the light coupling between the light emitting element 3 and the core portion 94 is large. This is effective from the viewpoint of increasing efficiency. In addition, since the area of the left end face of the widened portion 941 is large, the optical coupling efficiency between the light emitting element 3 and the core portion 94 is significantly reduced even if the position of the light emitting point is slightly deviated from the left end face of the widened portion 941. It is suppressed. Therefore, the allowable position when mounting the light emitting element 3 can be increased, and mounting ease is improved.

  When the width of the leftmost end of the widened portion 941 is W1, and the width of the rightmost end is W2, W2 is preferably about 0.1 to 0.9 times W1, more preferably It is about 0.2 to 0.8 times W1. Thereby, the widened part 941 which suppressed the leakage of the light from the core part 94 can be formed. As a result, the optical coupling efficiency between the light emitting element 3 and the core portion 94 can be further increased.

  In the widened portion 941, the angle α1 formed by the boundary line between the core portion 94 and the clad portion 95 and the end face of the left end portion of the core portion 94 is preferably 45 degrees or more and less than 90 degrees, more preferably It is set to 50 degrees or more and 85 degrees or less. Thereby, the widened portion 941 can be formed without impairing the reflection condition at the boundary surface between the core portion 94 and the clad portion 95. As a result, the optical coupling efficiency between the light emitting element 3 and the core portion 94 can be further increased. The angle between the boundary line between the core portion 94 and the clad portion 95 and the end face of the left end portion of the core portion 94 is α1 when the angle is 90 degrees or less.

  On the other hand, as shown in FIG. 1, by arranging the light receiving point of the light receiving element 4 so as to face the right end face of the reduced width portion 942, the light emitted from the reduced width portion 942 can be converted into a light receiving point with high efficiency. It can be made incident. In other words, the right end face of the reduced width portion 942 has a smaller area than the left end face, so that it is possible to emit more narrowly focused light and reliably enter the effective area of the light receiving point. Can be made. As a result, the optical coupling efficiency between the core portion 94 and the light receiving element 4 can be increased. In addition, since the area on the right side of the reduced width portion 942 is small, even if the position of the light receiving point with respect to the right end surface of the reduced width portion 942 is slightly shifted, the optical coupling efficiency between the light receiving element 4 and the core portion 94 is significantly reduced. It is suppressed. Therefore, the allowable position when mounting the light receiving element 4 can be increased, and mounting ease is improved.

  When the width of the leftmost end of the reduced width portion 942 is W3 and the width of the rightmost end is W4, W4 is preferably about 0.1 to 0.9 times W3, and more preferably. Is about 0.2 to 0.8 times W3. As a result, a reduced width portion 942 that suppresses light leakage from the core portion 94 can be formed. As a result, the optical coupling efficiency between the core portion 94 and the light receiving element 4 can be further increased.

  In the reduced width portion 942, the angle α2 formed by the boundary line between the core portion 94 and the cladding portion 95 and the end surface of the right end portion of the core portion 94 is preferably 45 degrees or more and less than 90 degrees, more preferably. Is 50 degrees or more and 85 degrees or less. Thereby, the reduced width portion 942 can be formed without impairing the reflection condition at the boundary surface between the core portion 94 and the cladding portion 95. As a result, the optical coupling efficiency between the core portion 94 and the light receiving element 4 can be further increased. The angle between the boundary line between the core portion 94 and the clad portion 95 and the end surface of the right end portion of the core portion 94 is α2 when the angle is 90 degrees or less.

  The width W1 is set to be larger than the width W4. As a result, the area of the left end face of the widened portion 941 becomes larger than the area of the right end face of the reduced width portion 942, so that the above-described effect can be obtained more reliably.

  The lengths of the widened portion 941 and the reduced portion 942 are not particularly limited, but are preferably about 3 to 10 times the width W2, for example.

FIG. 3B is another configuration example of the optical waveguide 9 shown in FIG.
The optical waveguide 9 shown in FIG. 3B is the same as the optical waveguide 9 shown in FIG. 3A except that the positions of the widened portion 941 and the reduced width portion 942 are different. That is, in FIG. 3A, the widened portion 941 is provided at the left end of the core portion 94 and the reduced portion 942 is provided at the right end, whereas in FIG. The portion 941 is moved inward (right side) by a predetermined distance from the left end of the core portion 94, and the reduced width portion 942 is inward (left side) by a predetermined distance from the right end of the core portion 94. Has moved to. A uniform width portion 940 having a constant cross-sectional area between the widened portion 941 and the left end surface of the core portion 94 and between the reduced width portion 942 and the right end surface of the core portion 94. Is located.

  In such an optical waveguide 9 shown in FIG. 3B, the width W1 of the left end portion of the widened portion 941 and the width W4 of the right end portion of the reduced width portion 942 are the same as in the case of FIG. Therefore, the same operation and effect as in FIG. That is, the optical waveguide 9 has high optical coupling efficiency with respect to the light emitting element 3 and the light receiving element 4.

  In addition, the position, the number, and the like of the widened portion 941 and the reduced portion 942 are not particularly limited, and a plurality of each may be provided.

Second Embodiment: FIG. 4
FIG. 4 shows a second embodiment of the optical waveguide structure 1 of the present invention. Hereinafter, although this optical waveguide structure 1 is demonstrated, the description is abbreviate | omitted about the matter similar to the said 1st Embodiment, and it demonstrates centering around difference.
FIG. 4 is a plan view showing the core layer of the second embodiment.

  The optical waveguide structure 1 of the present embodiment is the same as the optical waveguide 9 except for the configuration of the optical waveguide 9.

  That is, in the optical waveguide 9 shown in FIG. 4A, the boundary line between the core portion 94 and the cladding portion 95 in the widened portion 941 'and the reduced width portion 942' in a plan view forms a curve. This curve is a parabola that opens toward the left end (one end) of the core portion 94 in the widened portion 941 ′. In the reduced width portion 942 ′, this curve is a parabola that opens toward the left end (one end) of the core portion 94.

  In such a widened portion 941 ', the area of the left end face is large, so that the incident efficiency of incident light is improved. Further, when the light emitted from the light emitting element 3 and incident on the core portion 94 is reflected on the boundary surface between the core portion 94 and the clad portion 95, it is reflected so as to be condensed at the focal point of the parabola. As a result, the amount of light leakage in the core portion 94 can be reduced. In the reduced width portion 942 ′, the light propagating through the core portion 94 is condensed when reflected by the boundary surface between the core portion 94 and the cladding portion 95. As a result, more narrowly focused light can be emitted from the right end face of the reduced width portion 942 '. Thereby, the optical waveguide 9 shown in FIG. 4A has a high optical coupling efficiency with respect to the light emitting element 3 and the light receiving element 4.

FIG. 4B shows another configuration example of the optical waveguide 9 shown in FIG.
The optical waveguide 9 shown in FIG. 4B is the same as the optical waveguide 9 shown in FIG. 4A except that the positions of the widened portion 941 ′ and the reduced portion 942 ′ are different. That is, in FIG. 4A, the widened portion 941 ′ is provided at the left end portion of the core portion 94 and the reduced width portion 942 ′ is provided at the right end portion, whereas in FIG. The widened portion 941 ′ is moved inward (right side) by a predetermined distance from the left end portion of the core portion 94, and the reduced width portion 942 ′ is only a predetermined distance from the right end portion of the core portion 94. Moves inward (left side). The width (cross-sectional area) is constant between the widened portion 941 ′ and the left end portion of the core portion 94, and between the reduced width portion 942 ′ and the right end portion of the core portion 94. An equal width portion 940 is located.

  In such an optical waveguide 9 shown in FIG. 4B, the width W1 of the left end portion of the widened portion 941 ′ and the width W4 of the right end portion of the reduced width portion 942 ′ are as shown in FIG. 4A. Therefore, the same operations and effects as in FIG. That is, the optical waveguide 9 has high optical coupling efficiency with respect to the light emitting element 3 and the light receiving element 4.

<Third Embodiment: FIG. 5>
FIG. 5 shows a third embodiment of the optical waveguide structure 1 of the present invention. Hereinafter, although this optical waveguide structure 1 is demonstrated, the description is abbreviate | omitted about the matter similar to the said 1st Embodiment, and it demonstrates centering around difference.
FIG. 5 is a cross-sectional view showing a third embodiment.

  The optical waveguide structure 1 of the present embodiment is the same as the optical waveguide 9 except for the configuration of the optical waveguide 9.

  That is, the optical waveguide 9 shown in FIG. 5A has a thick film portion (expanded portion) 943 in which the thickness of the core layer 93 continuously increases toward the left end portion, and the right end portion. A thin film portion (reduced portion) 944 in which the thickness of the core layer 93 continuously decreases, and an equal thickness portion provided between the thick film portion 943 and the thin film portion 944 and having a constant thickness. 945. On the other hand, the width of the core portion 94 in plan view is constant although not shown. Accordingly, the thick film portion 943 shown in FIG. 5A is a portion where the cross-sectional area of the core portion 94 continuously increases toward the left end portion, and the thin film portion 944 is formed at the right end portion. This is a portion where the cross-sectional area of the core portion 94 continuously decreases. Furthermore, the equal thickness portion 945 is a portion where the cross-sectional area of the core portion 94 is constant.

  With respect to such an optical waveguide 9, the light emitting point of the light emitting element 3 is disposed so as to face the left end face of the thick film portion 943, thereby allowing light to enter the thick film portion 943 with high efficiency. be able to. That is, the optical coupling efficiency between the light emitting element 3 and the core portion 94 can be increased. In addition, since the area of the left end surface of the thick film portion 943 is large, the light coupling efficiency between the light emitting element 3 and the core portion 94 is remarkably increased even if the position of the light emitting point is slightly deviated from the left end surface of the thick film portion 943. Decrease is suppressed. Therefore, the allowable position when mounting the light emitting element 3 can be increased, and mounting ease is improved.

  When the thickness of the leftmost end of the thick film portion 943 is T1, and the thickness of the rightmost end is T2, T2 is preferably about 0.1 to 0.9 times T1. More preferably, it is about 0.2 to 0.8 times T1. Thereby, the thick film part 943 which suppressed the leakage of the light from the core part 94 can be formed. As a result, the optical coupling efficiency between the light emitting element 3 and the core portion 94 can be further increased.

  In the thick film portion 943, the angle β1 formed by the boundary line between the core portion 94 and each of the cladding layers 91 and 92 in the longitudinal section and the end face of the left end portion of the core portion 94 is preferably 45 degrees or more. It is less than 90 degrees, more preferably 50 degrees or more and 85 degrees or less. Thereby, the thick film portion 943 can be formed without impairing the reflection condition at the boundary surface between the core portion 94 and the clad layers 91 and 92. As a result, the optical coupling efficiency between the light emitting element 3 and the core portion 94 can be further increased. The angle between the boundary line between the core portion 94 and each of the cladding layers 91 and 92 and the end face of the left end portion of the core portion 94 is β1 when the angle is 90 degrees or less.

  On the other hand, as shown in FIG. 5A, by arranging the light receiving point of the light receiving element 4 so as to face the right end face of the thin film portion 944, the light emitted from the thin film portion 944 can be received with high efficiency. Can be made incident. In other words, the right end face of the thin film portion 944 has a smaller area than the left end face, so that it is possible to emit light that is more narrowly focused and reliably enter the effective area of the light receiving point. be able to. As a result, the optical coupling efficiency between the core portion 94 and the light receiving element 4 can be increased. In addition, since the area on the right side of the thin film portion 944 is small, even if the position of the light receiving point with respect to the right end surface of the thin film portion 944 is slightly shifted, the optical coupling efficiency between the light receiving element 4 and the core portion 94 may be significantly reduced. It is suppressed. Therefore, the allowable position when mounting the light receiving element 4 can be increased, and mounting ease is improved.

  Further, when the thickness of the leftmost end portion of the thin film portion 944 is T3 and the thickness of the rightmost end portion is T4, T4 is preferably about 0.1 to 0.9 times T3. Preferably, it is about 0.2 to 0.8 times T3. Thereby, the thin film part 944 which suppressed the leakage of the light from the core part 94 can be formed. As a result, the optical coupling efficiency between the core portion 94 and the light receiving element 4 can be further increased.

  In the thin film portion 944, an angle β2 formed by the boundary line between the core portion 94 and each of the cladding layers 91 and 92 in the longitudinal section and the end face of the right end portion of the core portion 94 is preferably 45 ° or more. It is less than 50 degrees, more preferably 50 degrees or more and 85 degrees or less. Thereby, the thin film portion 944 can be formed without impairing the reflection conditions at the boundary surface between the core portion 94 and the clad layers 91 and 92. As a result, the optical coupling efficiency between the core portion 94 and the light receiving element 4 can be further increased. The angle between the boundary line between the core portion 94 and each of the cladding layers 91 and 92 and the end face of the right end portion of the core portion 94 is β2 when the angle is 90 degrees or less.

  Further, the thickness T1 is set to be larger than the thickness T4. As a result, the area of the left end face of the thick film portion 943 is larger than the area of the right end face of the thin film portion 944, so that the above-described effect can be obtained more reliably.

  The lengths of the thick film portion 943 and the thin film portion 944 are not particularly limited, but are preferably about 3 to 10 times the width of the core portion 94, for example.

  On the other hand, the thickness of each cladding layer 91, 92 is constant regardless of the thick film portion 943 and the thin film portion 944.

FIG. 5B is another configuration example of the optical waveguide 9 shown in FIG.
The optical waveguide 9 shown in FIG. 5B is the same as the optical waveguide 9 shown in FIG. 5A except that the thicknesses of the clad layers 91 and 92 are partially different. That is, in FIG. 5B, the thickness of the portion corresponding to the thick film portion 943 in each of the cladding layers 91 and 92 continuously decreases toward the left end of the core portion 94, On the other hand, the thickness of the portion corresponding to the thin film portion 944 continuously increases toward the right end of the core portion 94. The total thickness of the optical waveguide 9 shown in FIG. 5B is constant as a whole.

  In such an optical waveguide 9, the optical coupling efficiency between the light emitting element 3 and the light receiving element 4 and the core portion 94 can be sufficiently increased as shown in FIG. 5A, and the mechanical strength of the thin film portion 944 can be increased. it can. That is, since the thickness of each of the cladding layers 91 and 92 is increased so as to compensate for the decrease in thickness in the thin film portion 944, the mechanical strength at the right end of the optical waveguide 9 is prevented from being lowered. Thereby, when the optical waveguide 9 and the light receiving element 4 are assembled, it is possible to prevent the right end from being damaged.

FIG. 5C shows another configuration example of the optical waveguide 9 shown in FIG.
The optical waveguide 9 shown in FIG. 5C is the same as the optical waveguide shown in FIG. 5A except that the thickness of the cladding layer 91 is partially different while the thickness of the cladding layer 92 is constant. The same as the waveguide 9. That is, in FIG. 5C, the thickness of the portion corresponding to the thick film portion 943 of the cladding layer 91 is continuously reduced toward the left end portion of the core portion 94, while the thin film portion 944 is formed. The thickness of the portion corresponding to is continuously increased toward the right end portion of the core portion 94. Further, the thickness of the cladding layer 92 is constant regardless of the thick film portion 943 and the thin film portion 944.

  In such an optical waveguide 9, the same operation and effect as the optical waveguide 9 shown in FIG.

FIG. 5D shows another configuration example of the optical waveguide 9 shown in FIG.
The optical waveguide 9 shown in FIG. 5D is the same as the optical waveguide 9 shown in FIG. 5A except that the positions of the thick film portion 943 and the thin film portion 944 are different. That is, in FIG. 5A, the thick film portion 943 is provided at the left end portion of the core portion 94 and the thin film portion 944 is provided at the right end portion, whereas in FIG. The membrane portion 943 is moved inward (right side) by a predetermined distance from the left end portion of the core portion 94, and the thin film portion 944 is inward (left side) by a predetermined distance from the right end portion of the core portion 94. Has moved to. A uniform thickness portion 945 having a constant cross-sectional area between the thick film portion 943 and the left end surface of the core portion 94 and between the thin film portion 944 and the right end surface of the core portion 94. Is located.

  In such an optical waveguide 9, the same operation and effect as the optical waveguide 9 shown in FIG.

  In the first and second embodiments described above, only the width of the core portion 94 is continuously changed. In the present embodiment (third embodiment), only the thickness of the core layer 93 is continuously changed. Although changing, both the width of the core portion 94 and the thickness of the core layer 93 may be continuously changed. That is, the thickness of the core layer 93 in the widened portion 941 may change as the thick film portion 943, and the thickness of the core layer 93 in the reduced width portion 942 may change as the thin film portion 944. . In this case, the operations and effects described above are more prominent than in each embodiment.

<Fourth Embodiment: FIG. 6>
FIG. 6 shows a fourth embodiment of the optical waveguide structure 1 of the present invention. Hereinafter, although this optical waveguide structure 1 is demonstrated, the description is abbreviate | omitted about the matter similar to the said 3rd Embodiment, and it demonstrates centering around difference.
FIG. 6 is a cross-sectional view showing the fourth embodiment.

  The optical waveguide structure 1 of the present embodiment is the same as the optical waveguide 9 except for the configuration of the optical waveguide 9.

  That is, in the optical waveguide 9 shown in FIG. 6A, the boundary lines between the core portion 94 and the clad layers 91 and 92 in the thick film portion 943 'and the thin film portion 944' in the cross section are curved. This curve is a parabola that opens toward the left end portion (one end portion) of the core portion 94 in the thick film portion 943 ′. In the thin film portion 944 ′, this curve is a parabola that opens toward the left end portion (one end portion) of the core portion 94.

  In such a thick film portion 943 ′, the area of the left end face is large, so that the incident efficiency of incident light is improved. Further, when the light emitted from the light emitting element 3 and incident on the core portion 94 is reflected on the boundary surface between the core portion 94 and the clad portion 95, it is reflected so as to be condensed at the focal point of the parabola. As a result, the amount of light leakage in the core portion 94 can be reduced. Also in the thin film portion 944 ′, the light propagating through the core portion 94 is condensed when reflected by the boundary surface between the core portion 94 and the clad portion 95. As a result, light narrowed down can be emitted from the right end face of the thin film portion 944 '. Accordingly, the optical waveguide 9 shown in FIG. 6A has a high optical coupling efficiency with respect to the light emitting element 3 and the light receiving element 4.

  FIG. 6B, FIG. 6C, and FIG. 6D are other configuration examples of the optical waveguide 9 shown in FIG.

  The boundary lines between the core portion 94 and the clad layers 91 and 92 in the thick film portion 943 and the thin film portion 944 shown in FIGS. 5 (b), 5 (c) and 5 (d) are parabolas. The optical waveguide 9 is the same as the optical waveguide 9 shown in FIG.

  In the first and second embodiments described above, only the width of the core portion 94 is continuously changed. In the present embodiment (fourth embodiment), only the thickness of the core layer 93 is continuously changed. Although changing, both the width of the core portion 94 and the thickness of the core layer 93 may be continuously changed. That is, the thickness of the core layer 93 in the widened portion 941 and the widened portion 941 ′ may change as in the thick film portion 943 and the thick film portion 943 ′, and the core layer in the reduced width portion 942 and the reduced width portion 942 ′. The thickness of 93 may be changed like the thin film portion 944 or the thin film portion 944 ′. In this case, the operations and effects described above are more prominent than in each embodiment.

<Fifth Embodiment: FIGS. 7 and 8>
FIG. 7 shows a fifth embodiment of the optical waveguide structure 1 of the present invention. Hereinafter, although this optical waveguide structure 1 is demonstrated, the description is abbreviate | omitted about the matter similar to the said 1st Embodiment, and it demonstrates centering around difference.
FIG. 7 is a cross-sectional view showing the fifth embodiment.

  The optical waveguide structure 1 of the present embodiment is the same as the above except for the configuration of the wiring board composed of the substrate 2 and the conductor layer 5.

  That is, the wiring board shown in FIG. 7 has the substrate 2 laminated on the upper surface of both ends in the longitudinal direction of the optical waveguide 9 and the conductor layer 5 provided on the upper surface of each substrate 2.

  On the left substrate 2 in FIG. 7, a surface-mounted light emitting element 3 and a light emitting IC (light emitting electrical element) 35 that drives light emission of the light emitting element 3 are mounted. The light emitting element 3 and the light emitting IC 35 are electrically connected via electric wiring formed on the conductor layer 5. Thereby, the light emission of the light emitting element 3 can be controlled by the light emitting IC 35. That is, the light emitting circuit 300 including the light emitting element 3 and the light emitting IC 35 is constructed on the left substrate 2.

  On the other hand, on the substrate 2 on the right side of FIG. 7, a surface mount type light receiving element 4 and a light receiving IC (light receiving electric element) 45 for amplifying a signal received by the light receiving element 4 are mounted. The light receiving element 4 and the light receiving IC 45 are electrically connected through electric wiring formed on the conductor layer 5. Thus, after receiving light by the light receiving element 4 and converting it to an electric signal, this electric signal is input to the light receiving IC 45 and amplified. That is, the light receiving circuit 400 having the light receiving element 4 and the light receiving IC 45 is constructed on the right substrate 2.

  In addition, an optical path conversion unit 971 is formed in the optical waveguide 9 at a position corresponding to a position directly below the light emitting unit 31 of the light emitting element 3. On the other hand, an optical path conversion unit 972 is formed in the optical waveguide 9 at a position corresponding to a position immediately below the light receiving unit 41 of the light receiving element 4.

  Each of the optical path conversion units 971 and 972 has a sloped surface in which a part of the inner surface of the removed part is inclined by approximately 45 ° with respect to the axis of the core part 94 of the optical waveguide 9 by removing a part of the optical waveguide 9. Formed to have. The inclined surface reflects the light from the light emitting unit 31 at an angle of 90 ° so as to guide the light to the core portion 94 or reflects the light propagated through the core portion 94 at an angle of 90 ° so as to guide the light to the light receiving portion 41. It functions as a reflective surface.

  The light emitting unit 31 and the light receiving unit 41 can be optically connected by the optical path conversion unit 971, the core unit 94, and the optical path conversion unit 972. Thereby, optical communication can be performed by transmitting and receiving light between the light emitting circuit 300 and the light receiving circuit 400.

  When the thickness of the substrate 2 is thin or the substrate 2 has translucency, the light-emitting element 3 and the light-receiving element 4 and the optical waveguide 9 are transmitted through the substrate 2 as shown in FIG. Can be optically connected, but if necessary, a through hole may be formed along the optical path of the light transmitted through the substrate 2.

  Moreover, you may make it provide a reflective film which consists of a metal film etc. in a reflective surface as needed. Furthermore, the removed portion may be filled with a material having a lower refractive index than that of the core portion 94.

FIG. 8 is a plan view showing the core layer 93 of the optical waveguide 9 provided in the fifth embodiment.
The core layer 93 (optical waveguide 9) shown in FIG. 8 includes a widened portion 941 in which the width of the core portion 94 continuously increases toward the left end portion in plan view, and the width of the core portion 94 at the right end. And a reduced width portion 942 that continuously decreases toward the portion.

  Further, the optical path conversion unit 971 adjacent to the widened portion 941 has an elongated shape so that the shape in plan view includes the left end face of the widened portion 941. Such an optical path changing unit 971 can efficiently receive and reflect the light emitted from the light emitting point of the light emitting element 3. As a result, the optical path conversion unit 971 contributes to an improvement in optical coupling efficiency between the light emitting element 3 and the core unit 94.

  On the other hand, the optical path conversion unit 972 adjacent to the reduced width portion 942 also has a shape including the right end surface of the reduced width portion 942 in a plan view. Since the narrowed light is emitted from the reduced width portion 942, the size of the optical path changing portion 972 can be reduced.

  The optical wiring 98 is constructed by the optical path conversion units 971 and 972 and the core unit 94.

  In FIG. 7, the substrates 2 are laminated on both ends of the optical waveguide 9, but the size of the substrate 2 may be large enough to be laminated over the entire optical waveguide 9. In this case, by providing the conductor layer 5 over the entire length of the substrate 2 and forming electric wiring in the conductor layer 5, electric communication can be performed in parallel with the optical communication described above. Thereby, the freedom degree of the circuit design of the optical waveguide structure 1 increases dramatically, and the integration degree of a circuit can also be improved. In addition, there is an advantage that it is not necessary to separately prepare a structure for telecommunications.

<Sixth Embodiment: FIGS. 9 and 10>
FIG. 9 shows a sixth embodiment of the optical waveguide structure 1 of the present invention. Hereinafter, although this optical waveguide structure 1 is demonstrated, the description is abbreviate | omitted about the matter similar to the said 1st, 5 embodiment, and it demonstrates centering around difference.
FIG. 9 is a plan view showing a core layer of an optical waveguide included in the sixth embodiment.

  The optical waveguide structure 1 of the present embodiment is the same as the optical waveguide 9 except for the configuration of the optical waveguide 9.

  That is, in the core layer 93 (optical waveguide 9) shown in FIG. 9, the optical wiring 98 constituted by the core portion 94 according to the fifth embodiment and the corresponding optical path changing portions 971 and 972 in plan view. Four (plural) are formed in parallel.

  Each of the four optical wirings 98 has an optical path conversion unit 971 and an optical path conversion unit 972 at each end, but the positions of the optical path conversion unit 971 and the optical path conversion unit 972 are inverted between adjacent ones. Yes. That is, among the four optical wirings 98, the one located at the top in FIG. 9 and the one located third from the top are formed such that the optical path conversion portion 971 is located on the left side of the core layer 93. Yes. On the other hand, among the four optical wirings 98, the ones located second and fourth from the top in FIG. 9 are formed so that the optical path conversion part 971 is located on the right side of the core layer 93.

  As described above, adjacent ones of the optical wirings 98 are alternately inverted in the longitudinal direction, so that the widened portions 941 that require a larger space are not adjacent to each other. Thereby, the optical wirings 98 can be arranged closer to each other, and the arrangement density of the optical wirings 98 can be increased. As a result, the optical waveguide structure 1 can be miniaturized and highly integrated.

  Of the four optical wirings 98, two of which the optical path conversion unit 971 is located on the right side and two of which the optical path conversion unit 971 is located on the left side are formed so as to be shifted in the longitudinal direction. Yes. As a result, the distance between the optical wirings 98 can be further reduced. This is because the optical path conversion unit 971 and the optical path conversion unit 972 that require a relatively large space are displaced in the longitudinal direction, so that these interferences can be avoided and a space can be provided between the optical wirings 98.

  The lengths of the four optical wirings 98 shown in FIG. 9 are almost the same, but when the lengths of the four optical wirings 98 are different, they are formed so that either the left side or the right side of the core part 94 is shifted. May be.

  In FIG. 9, of the four optical wirings 98, two of which the optical path conversion unit 971 is located on the right side and two of which the optical path conversion unit 971 is located on the left side are respectively in the longitudinal direction. Although they are formed at the same position, they may be formed so as to be displaced in the longitudinal direction. Thereby, the separation distance between the optical wirings 98 can be further reduced.

FIG. 10 is a plan view showing the sixth embodiment.
An optical waveguide structure 1 shown in FIG. 10 has a wiring board including a substrate 2 laminated on the upper surface of both end portions in the longitudinal direction of the optical waveguide 9 and a conductor layer 5 provided on the upper surface of each substrate 2. is doing.

  On the left substrate 2 in FIG. 10, two surface-mounted light emitting elements 3 and one light emitting IC 35 are mounted in accordance with the position of each optical path conversion unit 971. Each light emitting element 3 and the light emitting IC 35 are electrically connected through an electric wiring 51 formed in the conductor layer 5. Thereby, the light emission of the light emitting element 3 can be controlled by the light emitting IC 35. That is, the light emitting circuit 300 including the light emitting element 3 and the light emitting IC 35 is constructed on the left substrate 2.

  Also, on the left substrate 2, two surface-mounted light receiving elements 4 and one light receiving IC 45 are mounted in accordance with the position of each optical path conversion unit 972. Each light receiving element 4 and the light receiving IC 45 are electrically connected through an electric wiring 51 formed in the conductor layer 5. Thus, after receiving light by the light receiving element 4 and converting it to an electric signal, this electric signal is input to the light receiving IC 45 and amplified. That is, the light receiving circuit 400 including the light receiving element 4 and the light receiving IC 45 is also constructed on the left substrate, and the light emitting circuit 300 and the light receiving circuit 400 are mounted together.

  On the other hand, the light emitting circuit 300 and the light receiving circuit 400 are mixedly mounted on the right substrate 2 in FIG.

  According to such an optical waveguide structure 1, the light emitting circuit 300 corresponding to a plurality of channels and the light receiving circuit are formed on the substrate 2 having a relatively small area, despite having a plurality of optical communication channels (optical wirings 98). The circuit 400 can be mixedly mounted. As a result, the optical waveguide structure 1 can be miniaturized and highly integrated.

  As mentioned above, although 1st-6th embodiment was described, this invention is not limited to these, As long as the summary of invention is not changed, the thing of another structure may be sufficient. Further, the present invention may be a combination of configurations included in any two or more of the first to sixth embodiments.

  The optical waveguide structure of the present invention as described above is an optical waveguide that can increase the optical coupling efficiency when optically connected to a light emitting element, a light receiving element, another optical waveguide, or an optical communication component of an optical fiber. It will have. In particular, even when a light emitting element with low directivity or a light receiving element with a narrow effective light receiving area is connected, the transmission efficiency can be increased. In addition, since the allowable range of positional deviation between the optical waveguide and the optical communication component can be widened, the mounting of the optical waveguide or the optical communication component is facilitated, and the manufacturability of the optical waveguide structure is improved.

  In addition, since the optical waveguide structure of the present invention is provided, high-quality optical communication can be performed between two points, and thus a highly reliable electronic device (electronic device of the present invention) is obtained.

  Note that examples of the electronic device including the optical waveguide structure of the present invention include electronic devices such as a mobile phone, a game machine, a router device, a WDM device, a personal computer, a television, and a home server. In any of these electronic devices, it is necessary to transmit a large amount of data at high speed between an arithmetic device such as an LSI and a storage device such as a RAM. Therefore, since such an electronic device includes the optical waveguide structure according to the present invention, problems such as noise and signal degradation peculiar to electric wiring are eliminated, and a dramatic improvement in performance can be expected.

  In addition, the amount of heat generated in the optical waveguide portion is greatly reduced compared to electrical wiring. Therefore, the degree of integration in the substrate can be increased to reduce the size, the power required for cooling can be reduced, and the power consumption of the entire electronic device can be reduced.

<Optical waveguide manufacturing method>
Next, the manufacturing method of the optical waveguide 9 and the constituent materials of each part in each of the above embodiments will be described. In particular, the method for forming the core part 94 will be described in detail.

  First, prior to the description of the method for forming the core portion 94, the photosensitive resin composition used for forming the core portion 94 will be described.

(Photosensitive resin composition)
The photosensitive resin composition used in this embodiment is
(A) a cyclic olefin resin;
(B) The refractive index is different from (A), and at least one of a monomer having a cyclic ether group and an oligomer having a cyclic ether group;
(C) a photoacid generator;
Is provided.

Among these, from the viewpoint of reliably suppressing the occurrence of light propagation loss,
(C) a cyclic olefin resin (A) having a leaving group capable of leaving by an acid generated from a photoacid generator in the side chain;
It is preferable to contain the monomer of following formula (100).

  Such a photosensitive resin composition is formed into a film to be an optical waveguide forming film, and further used as a film including regions having different refractive indexes, for example, an optical waveguide film.

  That is, by using such a photosensitive resin composition, it is possible to provide an optical waveguide film or the like in which the occurrence of light propagation loss is suppressed. In particular, when a curved optical waveguide is formed, generation of light propagation loss can be remarkably suppressed.

  Furthermore, an optical / electrical hybrid substrate including an optical wiring using such an optical waveguide film, the optical wiring, and an electric circuit can be provided. According to such an optical wiring and an opto-electric hybrid board, it is possible to improve EMI (electromagnetic wave interference), which has been a problem with the conventional electrical wiring, and the signal transmission speed can be greatly improved as compared with the conventional one.

  In addition, an electronic device using the optical waveguide film can be provided. By using the optical waveguide film, space saving can be achieved, which contributes to downsizing of electronic devices.

  Specific examples of such an electronic device include a computer, a server, a mobile phone, a game device, a memory tester, and an appearance inspection robot.

Hereinafter, the components of the photosensitive resin composition will be described in detail.
((A) Cyclic olefin resin)
The cyclic olefin resin of component (A) is added in order to ensure the film moldability of the photosensitive resin composition, and serves as a base polymer.

  Here, the cyclic olefin resin may be unsubstituted, or hydrogen may be substituted with another group.

  Examples of the cyclic olefin resin include norbornene resins and benzocyclobutene resins.

  Especially, it is preferable to use norbornene-type resin from viewpoints, such as heat resistance and transparency.

As norbornene resin, for example,
(1) addition (co) polymer of norbornene type monomer obtained by addition (co) polymerization of norbornene type monomer,
(2) an addition copolymer of a norbornene monomer and ethylene or α-olefins,
(3) an addition polymer such as an addition copolymer of a norbornene-type monomer and a non-conjugated diene and, if necessary, another monomer;
(4) a ring-opening (co) polymer of a norbornene-type monomer, and a resin obtained by hydrogenating the (co) polymer if necessary,
(5) a ring-opening copolymer of a norbornene-type monomer and ethylene or α-olefins, and a resin obtained by hydrogenating the (co) polymer if necessary,
(6) Ring-opening copolymers such as norbornene-type monomers and non-conjugated dienes, or other monomers, and polymers obtained by hydrogenating the (co) polymers as necessary. Examples of these polymers include random copolymers, block copolymers, and alternating copolymers.

  These norbornene resins include, for example, ring-opening metathesis polymerization (ROMP), combination of ROMP and hydrogenation reaction, polymerization by radical or cation, polymerization using cationic palladium polymerization initiator, other polymerization initiators ( For example, it can be obtained by any known polymerization method such as polymerization using a polymerization initiator of nickel or another transition metal).

  Among these, as the norbornene-based resin, an addition (co) polymer is preferable. Addition (co) polymers are also preferred because they are rich in transparency, heat resistance and flexibility. For example, after forming a film with the photosensitive resin composition, an electrical component or the like may be mounted via solder. In such a case, an addition (co) polymer is preferable because it needs to have high heat resistance, that is, reflow resistance. Further, when a film is formed from the photosensitive resin composition and incorporated in a product, it may be used in an environment of about 80 ° C., for example. Even in such a case, an addition (co) polymer is preferable from the viewpoint of ensuring heat resistance.

  Among them, the norbornene-based resin preferably includes a norbornene repeating unit having a substituent containing a polymerizable group or a norbornene repeating unit having a substituent containing an aryl group.

  As the repeating unit of norbornene having a substituent containing a polymerizable group, the repeating unit of norbornene having a substituent containing an epoxy group, the repeating unit of norbornene having a substituent containing a (meth) acryl group, and an alkoxysilyl group At least one of the repeating units of norbornene having a substituent containing is preferable. These polymerizable groups are preferable because of their high reactivity among various polymerizable groups.

  Moreover, if the thing containing 2 or more types of repeating units of norbornene containing such a polymeric group is used, both flexibility and heat resistance can be aimed at.

  On the other hand, by including a norbornene repeating unit having a substituent containing an aryl group, dimensional change due to water absorption can be more reliably prevented by the extremely high hydrophobicity derived from the aryl group.

  Furthermore, the norbornene-based polymer preferably contains an alkylnorbornene repeating unit. The alkyl group may be linear or branched.

  By including the repeating unit of alkyl norbornene, the norbornene-based polymer has high flexibility, and thus can provide high flexibility (flexibility).

  A norbornene-based polymer containing an alkylnorbornene repeating unit is also preferable because of its excellent transmittance with respect to light in a specific wavelength region (particularly, a wavelength region near 850 nm).

  Therefore, as the norbornene-based resin, those represented by the following formulas (1) to (4) and (8) to (10) are preferable.

（式（１）中、Ｒ_１は、炭素数１〜１０のアルキル基を表し、ａは、０〜３の整数を表し、ｂは、１〜３の整数を表し、ｐ_１／ｑ_１が２０以下である。）

(In Formula (1), R ₁ represents an alkyl group having 1 to 10 carbon atoms, a represents an integer of 0 to 3, b represents an integer of 1 to 3, and p ₁ / q ₁ is 20 or less.)

The norbornene-based resin of the formula (1) can be produced as follows.
(1) is obtained by dissolving norbornene having R ₁ and norbornene having an epoxy group in the side chain in toluene and solution polymerization using Ni compound (A) as a catalyst.

  In addition, the manufacturing method of norbornene which has an epoxy group in a side chain is as (i) (ii), for example.

(I) Synthesis of norbornene methanol (NB—CH ₂ —OH) CPD (cyclopentadiene) and α olefin (CH ₂ ═CH—CH ₂ —OH) produced by cracking of DCPD (dicyclopentadiene) are heated under high temperature and high pressure. React.

(Ii) Synthesis of epoxy norbornene It is formed by the reaction of norbornene methanol and epichlorohydrin.

  In the formula (1), when b is 2 or 3, an epichlorohydrin in which the methylene group is an ethylene group, a propylene group or the like is used.

Among the norbornene-based resins represented by the formula (1), from the viewpoint that both flexibility and heat resistance can be achieved, in particular, R ₁ is an alkyl group having 4 to 10 carbon atoms, and a and A compound in which each b is 1, for example, a copolymer of butylbornene and methyl glycidyl ether norbornene, a copolymer of hexyl norbornene and methyl glycidyl ether norbornene, a copolymer of decyl norbornene and methyl glycidyl ether norbornene, or the like is preferable.

（式（２）中、Ｒ_２は、炭素数１〜１０のアルキル基を表し、Ｒ_３は、水素原子またはメチル基を表し、ｃは、０〜３の整数を表し、ｐ_２／ｑ_２が２０以下である。）

(In Formula (2), R ₂ represents an alkyl group having 1 to 10 carbon atoms, R ₃ represents a hydrogen atom or a methyl group, c represents an integer of 0 to 3, and p ₂ / q _2. Is 20 or less.)

The norbornene-based resin of the formula (2) is obtained by dissolving norbornene having R ₂ and norbornene having acryl and methacryl groups in the side chain in toluene, and performing solution polymerization using the Ni compound (A) described above as a catalyst. Obtainable.

Among the norbornene-based polymers represented by the formula (2), R ₂ is an alkyl group having 4 to 10 carbon atoms and c is 1 from the viewpoint of achieving both flexibility and heat resistance. Compounds such as copolymers of butylbornene and 2- (5-norbornenyl) methyl acrylate, copolymers of hexylnorbornene and 2- (5-norbornenyl) methyl acrylate, decylnorbornene and 2- (5-norbornenyl) methyl acrylate And a copolymer thereof are preferred.

（式（３）中、Ｒ_４は、炭素数１〜１０のアルキル基を表し、各Ｘ_３は、それぞれ独立して、炭素数１〜３のアルキル基を表し、ｄは、０〜３の整数を表し、ｐ_３／ｑ_３が２０以下である。）

(In Formula (3), R ₄ represents an alkyl group having 1 to 10 carbon atoms, each X ₃ independently represents an alkyl group having 1 to 3 carbon atoms, and d represents 0 to 3 carbon atoms. Represents an integer, and p ₃ / q ₃ is 20 or less.)

The resin of the formula (3) can be obtained by dissolving norbornene having R ₄ and norbornene having an alkoxysilyl group in the side chain in toluene, and solution polymerization using the Ni compound (A) described above as a catalyst. it can.

Among the norbornene-based polymers represented by the formula (3), in particular, a compound in which R ₄ is an alkyl group having 4 to 10 carbon atoms, d is 1 or 2, and X ₃ is a methyl group or an ethyl group, For example, a copolymer of butylbornene and norbornenylethyltrimethoxysilane, a copolymer of hexylnorbornene and norbornenylethyltrimethoxysilane, a copolymer of decylnorbornene and norbornenylethyltrimethoxysilane, butylbornene and triethoxysilylnorbornene Copolymer of hexyl norbornene and triethoxysilyl norbornene, copolymer of decyl norbornene and triethoxysilyl norbornene, copolymer of butylbornene and trimethoxysilyl norbornene, hexyl norbornene And copolymers of trimethoxysilyl norbornene, copolymers, etc. of decyl norbornene and trimethoxysilyl norbornene are preferred.

（式中、Ｒ_５は、炭素数１〜１０のアルキル基を表し、Ａ_１およびＡ_２は、それぞれ独立して、下記式（５）〜（７）で表される置換基を表すが、同時に同一の置換基であることはない。また、ｐ_４／ｑ_４＋ｒが２０以下である。）

(In the formula, R ₅ represents an alkyl group having 1 to 10 carbon atoms, and A ₁ and A ₂ each independently represent a substituent represented by the following formulas (5) to (7), (It is not the same substituent at the same time, and p ₄ / q ₄ + r is 20 or less.)

(4) is obtained by dissolving norbornene having R ₅ and norbornene having A ₁ and A ₂ in the side chain in toluene and solution polymerization using Ni compound (A) as a catalyst.

（式（５）中、ｅは、０〜３の整数を表し、ｆは、１〜３の整数を表す。）

(In formula (5), e represents an integer of 0 to 3, and f represents an integer of 1 to 3.)

（式（６）中、Ｒ_６は、水素原子またはメチル基を表し、ｇは、０〜３の整数を表す。）

(In formula (6), R ₆ represents a hydrogen atom or a methyl group, and g represents an integer of 0 to 3.)

（式（７）中、Ｘ_４は、それぞれ独立して、炭素数１〜３のアルキル基を表し、ｈは、０〜３の整数を表す。）

(Equation (7) in, _{X 4} each independently represents an alkyl group having 1 to 3 carbon atoms, h is. Represents an integer of 0 to 3)

  In addition, as a norbornene-type polymer represented by Formula (4), for example, any of butyl norbornene, hexyl norbornene or decyl norbornene, 2- (5-norbornenyl) methyl acrylate, norbornenyl ethyltrimethoxysilane, Terpolymer with either triethoxysilyl norbornene or trimethoxysilyl norbornene, terpolymer of butylbornene, hexylnorbornene or decylnorbornene, 2- (5-norbornenyl) methyl acrylate and methylglycidyl ether norbornene, butylbornene, Either hexyl norbornene or decyl norbornene and methyl glycidyl ether norbornene, norbornenyl ethyltrimethoxysilane, triethoxysilyl Terpolymers, etc. with either Ruborunen or trimethoxysilyl norbornene.

（式（８）中、Ｒ_７は、炭素数１〜１０のアルキル基を表し、Ｒ_８は、水素原子、メチル基またはエチル基を表し、Ａｒは、アリール基を表し、Ｘ_１は、酸素原子またはメチレン基を表し、Ｘ_２は、炭素原子またはシリコン原子を表し、ｉは、０〜３の整数を表し、ｊは、１〜３の整数を表し、ｐ_５／ｑ_５が２０以下である。）

(In formula (8), R ₇ represents an alkyl group having 1 to 10 carbon atoms, R ₈ represents a hydrogen atom, a methyl group or an ethyl group, Ar represents an aryl group, and X ₁ represents oxygen. X ₂ represents a carbon atom or a silicon atom, i represents an integer of 0 to 3, j represents an integer of 1 to 3, and p ₅ / q ₅ is 20 or less. is there.)

Norbornene having R ₇ and norbornene containing-(CH ₂ ) -X ₁ -X ₂ (R ₈ ) _3-j (Ar) _j in the side chain are dissolved in toluene, and solution polymerization is performed using a Ni compound as a catalyst. (8) is obtained.

Of the norbornene polymers represented by the formula (8), those in which X ₁ is an oxygen atom, X ₂ is a silicon atom, and Ar is a phenyl group are preferable.

Further, particularly from the viewpoint of flexibility, heat resistance and refractive index control, R ₇ is an alkyl group having 4 to 10 carbon atoms, X ₁ is an oxygen atom, X ₂ is a silicon atom, Ar is a phenyl group, R _A compound in which ₈ is a methyl group, i is 1 and j is 2, for example, a copolymer of butylbornene and diphenylmethylnorbornenemethoxysilane, a copolymer of hexylnorbornene and diphenylmethylnorbornenemethoxysilane, decylnorbornene and diphenylmethylnorbornenemethoxysilane Of these, the copolymer is preferred.
Specifically, it is preferable to use the following norbornene resin.

（式（９）におけるＲ_７、ｐ_５、ｑ_５、ｉは、式（８）と同じである。）

(R ₇ , p ₅ , q ₅ , and i in formula (9) are the same as in formula (8).)

From the viewpoint of flexibility, heat resistance, and refractive index control, in Formula (8), R ₇ is an alkyl group having 4 to 10 carbon atoms, X ₁ is a methylene group, X ₂ is a carbon atom, and Ar is Compounds having a phenyl group, R ₈ is a hydrogen atom, i is 0, and j is 1, for example, a copolymer of butylbornene and phenylethylnorbornene, a copolymer of hexylnorbornene and phenylethylnorbornene, a copolymer of decylnorbornene and phenylethylnorbornene Etc.
Further, the following may be used as the norbornene resin.

（式（１０）において、Ｒ_１０は、炭素数１〜１０のアルキル基を表し、Ｒ_１１は、アリール基を示し、ｋは０以上、４以下である。ｐ_６／ｑ_６は２０以下である。）

(In Formula (10), R ₁₀ represents an alkyl group having 1 to 10 carbon atoms, R ₁₁ represents an aryl group, and k is 0 or more and 4 or less. P ₆ / q ₆ is 20 or less. is there.)

P ₁ / q _{1 to} p ₃ / q ₃ , p ₅ / q ₅ , p ₆ / q ₆ or p ₄ / q ₄ + r may be 20 or less, preferably 15 or less, About 0.1-10 is more preferable. Thereby, the effect including the repeating unit of multiple types of norbornene is exhibited.

  The norbornene-based resin as described above preferably has a leaving group. Here, the leaving group is a group that is released by the action of an acid.

  Specifically, those having at least one of an —O— structure, an —Si—aryl structure, and an —O—Si— structure in the molecular structure are preferable. Such an acid leaving group is released relatively easily by the action of a cation.

  Among these, as the leaving group that causes a decrease in the refractive index of the resin by leaving, at least one of the -Si-diphenyl structure and the -O-Si-diphenyl structure is preferable.

For example, among the norbornene polymers represented by the formula (8), those in which X ₁ is an oxygen atom, X ₂ is a silicon atom, and Ar is a phenyl group have a leaving group.

In the formula (3), there is a case where the Si—O—X ₃ part of the alkoxysilyl group is eliminated.

  For example, when the norbornene resin of formula (9) is used, it is presumed that the reaction proceeds as follows by the acid generated from the photoacid generator (denoted as PAG). Here, only the leaving group portion is shown, and the case where i = 1 is described.

Furthermore, in addition to the structure of the formula (9), the side chain may have an epoxy group. By using such a material, there is an effect that a film having excellent adhesion can be formed.
A specific example is as follows.

（式（３１）において、ｐ_７／ｑ_７＋ｒ_２は、２０以下である。）

(In formula (31), p ₇ / q ₇ + r ₂ is 20 or less.)

The compound represented by the formula (31) includes, for example, hexyl norbornene, diphenylmethyl norbornene methoxysilane (norbornene containing -CH ₂ -O-Si (CH ₃ ) (Ph) ₂ in the side chain) and epoxy norbornene in toluene. It can be obtained by dissolving and solution polymerization using a Ni compound as a catalyst.

((B) Monomer having a cyclic ether group, oligomer having a cyclic ether group)
Next, the component (B) will be described.

  Component (B) is at least one of a monomer having a cyclic ether group and an oligomer having a cyclic ether group. This component (B) may have any refractive index different from that of the resin of component (A) and is compatible with the resin of component (A). The refractive index difference between the component (B) and the resin of the component (A) is preferably 0.01 or more.

  The refractive index of the component (B) may be higher than that of the resin of the component (A), but the refractive index of the component (B) is preferably lower than that of the resin of the component (A).

  The monomer having a cyclic ether group and the oligomer having a cyclic ether group as component (B) are polymerized by ring-opening in the presence of an acid. Considering the diffusibility of the monomer and oligomer, the molecular weight (weight average molecular weight) of the monomer and the molecular weight (weight average molecular weight) of the oligomer are preferably 100 or more and 400 or less, respectively.

  Component (B) has, for example, an oxetanyl group or an epoxy group. Such a cyclic ether group is preferable because it is easily opened by an acid.

  As the monomer having an oxetanyl group and the oligomer having an oxetanyl group, those selected from the following formulas (11) to (20) are preferable. By using these, there is an advantage that transparency in the vicinity of a wavelength of 850 nm is excellent and both flexibility and heat resistance are possible. These may be used alone or in combination.

（式（１８）においてｎは０以上、３以下である。）

(In formula (18), n is 0 or more and 3 or less.)

  Among the above monomers and oligomers, they are represented by the formulas (13), (15), (16), (17), and (20) from the viewpoint of ensuring a difference in refractive index from the resin of the component (A). It is preferable to use a compound.

  Furthermore, considering the point that there is a difference in refractive index from the resin of component (A), the point that the molecular weight is small, the mobility of the monomer is high, and the point that the monomer does not easily volatilize, the formulas (20) and (15) It is particularly preferable to use a compound represented by:

  Moreover, as a compound which has an oxetanyl group, the compound represented by the following formula | equation (32) and a formula (33) can be used. As a compound represented by Formula (32), Toagosei Co., Ltd. trade name TESOX etc., and as a compound represented by Formula (33), Toagosei Co., Ltd. trade name OX-SQ etc. can be used.

（式（３３）において、ｎは１または２である）

(In formula (33), n is 1 or 2)

  Examples of the monomer having an epoxy group and the oligomer having an epoxy group include the following. The monomer and oligomer having an epoxy group are polymerized by ring-opening in the presence of an acid.

  As the monomer having an epoxy group and the oligomer having an epoxy group, those represented by the following formulas (34) to (39) can be used. Especially, it is preferable to use the alicyclic epoxy monomer represented by Formula (36)-(39) from a viewpoint that the distortion energy of an epoxy ring is large and is excellent in reactivity.

  In addition, the compound represented by Formula (34) is epoxy norbornene. As such a compound, for example, EpNB manufactured by Promerus Corporation can be used. The compound represented by the formula (35) is γ-glycidoxypropyltrimethoxysilane. As this compound, for example, Z-6040 manufactured by Toray Dow Corning Silicone can be used. The compound represented by the formula (36) is 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and as this compound, for example, E0327 manufactured by Tokyo Chemical Industry can be used.

  Furthermore, the compound represented by the formula (37) is 3,4-epoxycyclohexenylmethyl-3, '4'-epoxycyclohexenecarboxylate. As this compound, for example, Celoxide 2021P manufactured by Daicel Chemical Industries, Ltd. is used. can do. Further, the compound represented by the formula (38) is 1,2-epoxy-4-vinylcyclohexane. As this compound, for example, Celoxide 2000 manufactured by Daicel Chemical Industries, Ltd. can be used.

  Furthermore, the compound represented by the formula (39) is 1,2: 8,9 diepoxy limonene. As this compound, for example, (Celoxide 3000 manufactured by Daicel Chemical Industries, Ltd.) can be used.

  Furthermore, as the component (B), a monomer having an oxetanyl group, an oligomer having an oxetanyl group, a monomer having an epoxy group, and an oligomer having an epoxy group may be used in combination.

  Monomers having an oxetanyl group and oligomers having an oxetanyl group have a slow initiation reaction but a fast growth reaction. On the other hand, a monomer having an epoxy group and an oligomer having an epoxy group have a fast initiation reaction for initiating polymerization but a slow growth reaction. Therefore, by using a monomer having an oxetanyl group, an oligomer having an oxetanyl group, a monomer having an epoxy group, and an oligomer having an epoxy group, when irradiated with light, the light irradiated portion and the unirradiated portion A difference in refractive index can be reliably generated.

  The addition amount of the component (B) is preferably 1 part by weight or more and 50 parts by weight or less, more preferably 2 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the component (A). . Thereby, the refractive index modulation between the core and the clad is possible, and there is an effect that both flexibility and heat resistance can be achieved.

((C) Photoacid generator)
Any photoacid generator may be used as long as it absorbs light energy to generate Bronsted acid or Lewis acid. For example, triphenylsulfonium trifluoromethanesulfonate, tris (4-t-butylphenyl) sulfonium- Sulfonium salts such as trifluoromethanesulfonate, diazonium salts such as p-nitrophenyldiazonium hexafluorophosphate, ammonium salts, phosphonium salts, diphenyliodonium trifluoromethanesulfonate, iodonium salts such as (triccumyl) iodonium-tetrakis (pentafluorophenyl) borate, Quinonediazides, diazomethanes such as bis (phenylsulfonyl) diazomethane, 1-phenyl-1- (4-methylphenyl) sulfonyl Sulfonic acid esters such as xyl-1-benzoylmethane and N-hydroxynaphthalimide-trifluoromethanesulfonate, disulfones such as diphenyldisulfone, tris (2,4,6-trichloromethyl) -s-triazine, 2- ( And compounds such as triazines such as 3.4-methylenedioxyphenyl) -4,6-bis- (trichloromethyl) -s-triazine. These photoacid generators can be used alone or in combination.

  The content of the photoacid generator is preferably 0.01 parts by weight or more and 0.3 parts by weight or less with respect to 100 parts by weight of the component (A), and is 0.02 parts by weight or more and 0.2 parts by weight or less. It is more preferable that Thereby, there exists an effect of a reactive improvement.

  The photosensitive resin composition may contain additives such as a sensitizer in addition to the above components (A), (B), and (C).

  The sensitizer increases the sensitivity of the photoacid generator to light and is suitable for reducing the time and energy required for activation (reaction or decomposition) of the photoacid generator and for activating the photoacid generator. It has a function of changing the wavelength of light to a wavelength.

  Such a sensitizer is appropriately selected according to the sensitivity of the photoacid generator and the peak wavelength of absorption of the sensitizer, and is not particularly limited. For example, 9,10-dibutoxyanthracene (CAS No. 76275) is selected. -14-4) anthracenes, xanthones, anthraquinones, phenanthrenes, chrysene, benzpyrenes, fluoranthenes, rubrenes, pyrenes, indanthrines, thioxanthen-9-one (Thioxanthen-9-ones) and the like, and these can be used alone or as a mixture.

  Specific examples of the sensitizer include, for example, 2-isopropyl-9H-thioxanthen-9-one, 4-isopropyl-9H-thioxanthen-9-one, 1-chloro-4-propoxythioxanthone, phenothiazine. Or a mixture thereof.

  The content of the sensitizer in the photosensitive resin composition is preferably 0.01% by weight or more, more preferably 0.5% by weight or more, and further preferably 1% by weight or more. preferable. In addition, it is preferable that an upper limit is 5 weight% or less.

  Among the above photosensitive resin compositions, the cyclic olefin resin having a leaving group in the side chain as the component (A), the photoacid generator of the component (C), and the following formula (100) as the component (B) The photosensitive resin composition containing the 1st monomer as described in above is especially preferable.

Hereinafter, this particularly preferable photosensitive resin composition will be described.
As the cyclic olefin resin (A) constituting the cyclic olefin resin having a leaving group in the side chain, those described above can be used. For example, polymers of monocyclic monomers such as cyclohexene and cyclooctene, Examples include polymers of polycyclic monomers such as norbornene, norbornadiene, dicyclopentadiene, dihydrodicyclopentadiene, tetracyclododecene, tricyclopentadiene, dihydrotricyclopentadiene, tetracyclopentadiene, and dihydrotetracyclopentadiene. Among these, one or more cyclic olefin resins selected from polymers of polycyclic monomers are preferably used. Thereby, the heat resistance of resin can be improved.

  In addition, as polymerization forms, known forms such as random polymerization and block polymerization can be applied. For example, specific examples of polymerization of norbornene type monomers include (co) polymers of norbornene type monomers, copolymers of norbornene type monomers and other monomers capable of copolymerization such as α-olefins, and the like. A hydrogenated product of the above copolymer corresponds to a specific example. These cyclic olefin resins can be produced by a known polymerization method. The polymerization methods include an addition polymerization method and a ring-opening polymerization method. Among the above, the cyclic olefin resin (particularly, the addition polymerization method) Norbornene resin) is preferable (that is, an addition polymer of a norbornene compound). Thereby, it is excellent in transparency, heat resistance, and flexibility.

As the leaving group, a part of the molecule is cleaved by the action of an acid (H ⁺ ) generated from a photoacid generator, and then leaves. Specifically, those having at least one of the aforementioned -O- structure, -Si-aryl structure and -O-Si- structure in the molecular structure (side chain) are preferable. The leaving group as described above is released relatively easily by the action of acid (H ⁺ ).

  Among the above-described leaving groups, the leaving group that causes a decrease in the refractive index of the resin by leaving is preferably at least one of a -Si-diphenyl structure and a -O-Si-diphenyl structure.

  The content of the leaving group is not particularly limited, but is preferably 10 to 80% by weight, particularly 20 to 60% by weight in the cyclic olefin resin having a leaving group in the side chain. Is more preferable. When the content is within the above range, it is particularly excellent in both flexibility and refractive index modulation function (effect of increasing the refractive index difference).

  As such a cyclic olefin resin having a leaving group in the side chain, one having a repeating unit represented by the following formula (101) and / or the following formula (102) is preferable. Thereby, the refractive index of resin can be made high.

（式１０１においてｎは０以上、９以下の整数である。）

(In Formula 101, n is an integer of 0 or more and 9 or less.)

  The photosensitive resin composition includes a monomer described in the above formula (100) (hereinafter referred to as a first monomer). Thereby, the refractive index difference between the left and right cores / claddings can be further expanded.

  The content of the first monomer is not particularly limited, but is preferably 1 part by weight or more and 50 parts by weight or less, particularly 2 parts by weight, based on 100 parts by weight of the cyclic olefin resin having a leaving group in the side chain. It is preferable that it is 20 parts by weight or more. Thereby, the refractive index modulation between the core / cladding is made possible, and both flexibility and heat resistance can be achieved.

  Thus, when the first monomer described above is used in combination with a cyclic olefin resin having a leaving group in the side chain, the reason for excellent balance between the refractive index modulation between the core and the clad and flexibility is as follows. It is considered as follows.

  First, when using the photosensitive resin composition as described above, it is excellent in the refractive index modulation between the core and the clad when the first monomer starts a polymerization reaction by an acid generated by light irradiation or the like. This is because the first monomer is excellent in the reactivity. When the reactivity of the first monomer is excellent, the curability of the first monomer is increased, and the diffusibility of the first monomer caused by the concentration gradient of the first monomer is improved. Thereby, the refractive index difference between the light irradiation region and the non-irradiation region can be increased.

  Further, since the first monomer is monofunctional, the polymerization reaction proceeds and the crosslinking density as the photosensitive resin composition does not become so high. Therefore, it is excellent in flexibility.

  Although the said photosensitive resin composition is not specifically limited, The 2nd monomer different from the said 1st monomer may be included. The second monomer different from the first monomer may be a monomer having a different structure or a monomer having a different molecular weight.

  Especially, the 2nd monomer is contained as a component (B), for example, an oxetane compound different from what is shown by an epoxy compound, Formula (100), a vinyl ether compound, etc. are mentioned. Among these, at least one of an epoxy compound (particularly an alicyclic epoxy compound) and a bifunctional oxetane compound (a monomer having two oxetanyl groups) is preferable. Thereby, the reactivity of the first monomer and the cyclic olefin resin can be improved, whereby the heat resistance of the waveguide can be improved while maintaining transparency.

  Specifically, the second monomer includes the compound of the above formula (15), the compound of the above formula (12), the compound of the above formula (11), the compound of the above formula (18), and the compound of the above formula (19). And compounds of the above formulas (34) to (39).

  The content of the second monomer is not particularly limited, but is preferably 1 part by weight or more and 50 parts by weight or less, particularly 2 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the cyclic olefin resin. More preferably. Thereby, the reactivity with the first monomer can be improved.

  Further, the combined ratio of the second monomer and the first monomer is not particularly limited, but is preferably 0.1 to 1 in weight ratio (weight of the second monomer / weight of the first monomer), particularly 0. .1 to 0.6 are preferred. When the combined ratio is within the above range, the balance between the speed of reactivity and the heat resistance of the waveguide is excellent.

  Although content of a photo-acid generator is not specifically limited, It is 0.01 weight part or more and 0.3 weight part or less with respect to 100 weight part of cyclic olefin resin which has a leaving group in the said side chain. In particular, it is more preferably 0.02 parts by weight or more and 0.2 parts by weight or less. If the content is less than the lower limit, the reactivity may decrease, and if the content exceeds the upper limit, the optical waveguide may be colored and light loss may decrease.

  The photosensitive resin composition may contain a curing catalyst, an antioxidant, and the like in addition to the above-mentioned cyclic olefin resin, photoacid generator, first monomer and second monomer.

  Further, the above-described photosensitive resin composition can be used as a composition for forming the core portion 94.

(First optical waveguide manufacturing method)
11 to 13 are cross-sectional views schematically showing process examples of the first method for manufacturing an optical waveguide.

  Here, a method for producing an optical waveguide using a photosensitive resin composition when the component (B) has a lower refractive index than the cyclic olefin resin of the component (A) will be described as an example.

  First, as shown in FIG. 11A, a varnish 900 is prepared by dissolving a photosensitive resin composition in a solvent, and this varnish 900 is applied onto a clad layer 91.

  Examples of the solvent for preparing the photosensitive resin composition in the form of varnish include diethyl ether, diisopropyl ether, 1,2-dimethoxyethane (DME), 1,4-dioxane, tetrahydrofuran (THF), tetrahydropyran (THP), Ether solvents such as anisole, diethylene glycol dimethyl ether (diglyme), diethylene glycol ethyl ether (carbitol), cellosolv solvents such as methyl cellosolve, ethyl cellosolve, phenyl cellosolve, aliphatic hydrocarbon solvents such as hexane, pentane, heptane, cyclohexane , Toluene, xylene, benzene, mesitylene and other aromatic hydrocarbon solvents, pyridine, pyrazine, furan, pyrrole, thiophene, methylpyrrolidone and other aromatic heterocyclic compounds Amide solvents such as N, N-dimethylformamide (DMF) and N, N-dimethylacetamide (DMA), halogen compound solvents such as dichloromethane, chloroform and 1,2-dichloroethane, ethyl acetate, methyl acetate, ethyl formate, etc. Ester solvents, various organic solvents such as sulfur compound solvents such as dimethyl sulfoxide (DMSO) and sulfolane, or mixed solvents containing them.

  Next, the varnish 900 is applied on the cladding layer 91 of the optical waveguide 9 and then dried to evaporate (desolve) the solvent. Accordingly, as shown in FIG. 11B, the varnish 900 becomes a film 910 for forming an optical waveguide. The film 910 becomes a core layer 93 in which a core portion 94 and a clad portion 95 are formed by light irradiation described later.

  Here, examples of the method of applying the varnish 900 include a doctor blade method, a spin coating method, a dipping method, a table coating method, a spray method, an applicator method, a curtain coating method, and a die coating method. It is not limited. As the clad layer 91, for example, a sheet having a refractive index lower than that of a core portion 94 described later is used, and for example, a sheet containing a norbornene-based resin and an epoxy resin is used.

Next, the film 910 is selectively irradiated with light (for example, ultraviolet rays).
At this time, as shown in FIG. 12A, a mask M in which an opening is formed is disposed above the film 910. The film 910 is irradiated with light through the opening of the mask M.

  As light used, what has a peak wavelength in the range of wavelength 200-450 nm is mentioned, for example. Thereby, although depending on the composition of the photoacid generator, the photoacid generator can be activated relatively easily.

The irradiation amount of light is not particularly limited, and is preferably about 0.1~9J / cm ^2, more preferably about 0.2~6J / cm ^2, 0.2~3J / More preferably, it is about cm ² .

  Note that the use of the mask M can be omitted when highly directional light such as laser light is used.

  In the region of the film 910 that is irradiated with light, an acid is generated from the photoacid generator. The component (B) is polymerized by the generated acid.

  In the region not irradiated with light, no acid is generated from the photoacid generator, so that component (B) is not polymerized. In the irradiated part, since the component (B) is polymerized to become a polymer, the amount of the component (B) is reduced. In response to this, the component (B) of the unirradiated part diffuses into the irradiated part, thereby causing a refractive index difference between the irradiated part and the unirradiated part.

  Here, when the component (B) has a lower refractive index than the cyclic olefin resin, the component (B) of the unirradiated part diffuses into the irradiated part, and the refractive index of the unirradiated part increases. The refractive index of the irradiated part is lowered.

  In addition, the refractive index difference between the polymer obtained by polymerizing the component (B) and the monomer having a cyclic ether group is about 0 or more and 0.001 or less, and the refractive indexes are considered to be substantially the same.

  Thus, when the photosensitive resin composition mentioned above is used, it is possible to start superposition | polymerization of a component (B) with the acid generate | occur | produced from a photo-acid generator.

  Furthermore, the cyclic olefin resin used in the present invention does not necessarily have a leaving group, but when a cyclic olefin resin having a leaving group is used as the component (A), The following effects occur.

  In the portion irradiated with light, the leaving group of the cyclic olefin resin is eliminated by the acid generated from the photoacid generator. In the case of a leaving group such as a -Si-aryl structure, a -Si-diphenyl structure, and a -O-Si-diphenyl structure, the refractive index of the resin decreases due to the leaving. Therefore, the refractive index of the irradiated portion is further lowered as compared with that before the leaving group is removed.

  Next, the film 910 is heated. In this heating step, the component (B) of the irradiated portion irradiated with light is further polymerized. On the other hand, in this heating step, the component (B) in the unirradiated part is volatilized. Thereby, in an unirradiated part, a component (B) decreases and it becomes a refractive index close | similar to cyclic olefin resin.

  In this film 910, as shown in FIG. 12B, the region irradiated with light becomes the cladding portion 95, and the non-irradiated region becomes the core portion 94. The structure concentration derived from the component (B) in the core portion 94 and the structure concentration derived from the component (B) in the cladding portion 95 are different. Specifically, the structure concentration derived from the component (B) in the core portion 94 is lower than the structure concentration derived from the component (B) in the cladding portion 95.

  The clad part 95 has a lower refractive index than the core part 94, and the refractive index difference between the clad part 95 and the core part 94 is 0.01 or more. As described above, the core portion 94 and the clad portion 95 are formed on the film 910, and the core layer 93 is obtained.

  The heating temperature in this heating step is not particularly limited, but is preferably about 30 to 180 ° C, and more preferably about 40 to 160 ° C.

  In addition, the heating time is preferably set so that the polymerization reaction of the component (B) of the irradiated part irradiated with light is almost completed, specifically, preferably about 0.1 to 2 hours, More preferably, it is about 0.1 to 1 hour.

  Thereafter, a film similar to the clad layer 91 is attached on the core layer 93. This film becomes the clad layer 92. The pair of clad layers 91 and 92 are arranged so as to sandwich the core portion 94 from a direction different from the clad portion 95.

The clad layer 92 can also be formed by a method of applying a liquid material on the core layer 93 and curing (solidifying) instead of attaching a film-like one.
Through the above steps, the optical waveguide 9 shown in FIG. 13 is obtained.

  Further, when the optical waveguide 9 is obtained from the photosensitive resin composition used in the present invention, the solder reflow resistance is particularly excellent. Furthermore, even when the optical waveguide 9 is bent, the optical loss can be reduced.

  In the above description, the case where the photosensitive resin composition is directly supplied onto the clad layer 91 to form the film 910 (core layer 93) has been described, but the film 910 (core layer) is formed on another substrate. 93), the obtained core layer 93 may be transferred onto the clad layer 91 or the clad layer 92, and then the clad layer 91 and the clad layer 92 may be overlapped via the core layer 93. .

Next, the effect of this embodiment is demonstrated.
When light is applied to the photosensitive resin composition used in the present embodiment, an acid is generated from the photoacid generator, and the component (B) is polymerized only in the irradiated portion. Then, since the amount of the component (B) in the irradiated part is reduced, the component (B) in the non-irradiated part diffuses into the irradiated part, thereby causing a difference in refractive index between the irradiated part and the unirradiated part. Specifically, in this embodiment, since a substituted or unsubstituted cyclic olefin resin having a higher refractive index than that of the component (B) is used as the base polymer, the component (B) in the unirradiated portion is irradiated with the irradiated portion. The refractive index of the unirradiated part becomes higher than the refractive index of the irradiated part.

  In addition to this, when the photosensitive resin composition is heated after light irradiation, the component (B) volatilizes from the unirradiated portion. Thereby, a refractive index difference further occurs between the irradiated portion and the unirradiated portion.

  Thus, by using the photosensitive resin composition, a refractive index difference can be reliably formed between the irradiated portion and the unirradiated portion. Further, according to the present invention, the core portion can be patterned by a simple method of simply irradiating light. For example, by appropriately selecting an exposure pattern such as a photomask, an optical path (core part) of any shape and arrangement can be formed, and a thin optical path can be formed sharply. This contributes to integration, and the device can be miniaturized. That is, according to the present invention, a core portion having a wide degree of freedom in designing the pattern shape of the core portion and high dimensional accuracy can be obtained.

  Conventionally, a technique for crosslinking a norbornene-based resin having an oxetanyl group or the like with a thermal acid generator is known. However, the composition used in such a technique contains a norbornene-based resin having an oxetanyl group or the like as a base polymer. And the whole composition is heated and a crosslinked structure is produced in the whole composition. Therefore, this composition that has been conventionally used is selectively irradiated with light to generate acid, thereby selectively causing polymerization, and the monomer diffuses into the region where the monomer concentration is reduced, There is no technical idea that density differences can be made.

  In contrast, when the photosensitive resin composition used in the present embodiment is selectively irradiated with light, the amount of the component (B) in the irradiated portion is reduced due to the generation of acid, so the component (B) in the unirradiated portion Has been found to diffuse into the irradiated portion, which causes a difference in refractive index between the irradiated portion and the unirradiated portion.

  Further, when the cyclic olefin resin has a leaving group that is desorbed by an acid generated from the photoacid generator and reduces the refractive index of the cyclic olefin resin of the component (A) by desorption, The refractive index of the region irradiated with light can be reliably reduced as compared with the unirradiated region.

  On the other hand, when the cyclic olefin resin has no leaving group, the side chain is chemically stable, so the refractive index of the core part and the clad part depends on conditions such as light irradiation and heating. Can be prevented from fluctuating.

  Furthermore, in this embodiment, norbornene-type resin is used as a component (A). Thereby, the light transmittance in a specific wavelength can be improved reliably, and reduction of propagation loss can be aimed at reliably.

  Further, the clad part 95 has a lower refractive index than the core part 94, and the difference in refractive index between the clad part 95 and the core part 94 is 0.01 or more, so that light can be reliably confined in the core part 94. And the generation of light propagation loss can be suppressed.

  On the other hand, conventionally, as a composition for forming an optical waveguide, a composition containing a polymer, a monomer, a promoter and a catalyst precursor is known.

  Among these, the monomer can form a reaction product by irradiation of light, and can make the refractive index of the region irradiated with light different from the refractive index of the unirradiated region.

  The catalyst precursor is a substance capable of initiating a monomer reaction (polymerization reaction, crosslinking reaction, etc.), and is a substance whose activation temperature is changed by the action of a promoter activated by light irradiation. Due to the change in the activation temperature, the temperature at which the monomer reaction starts is different between the light irradiation region and the non-irradiation region, and as a result, a reactant can be formed only in the irradiation region.

  However, since this catalyst precursor contains a relatively large amount of a metal element such as palladium, it has the side effect of increasing the propagation loss by absorbing light propagating through the optical waveguide. In particular, the tendency was remarkable when the optical waveguide was bent. Further, since the catalyst precursor is contained, there is a problem that heat resistance is lowered and propagation efficiency is lowered during reflow.

Even when such a conventional composition is used, the core part and the clad part can be separately formed by light irradiation. However, according to the photosensitive resin composition used in the present embodiment, the core part 94 and the clad part. Since the difference in refractive index from 95 is further increased and the heat resistance is improved, the optical waveguide 9 having higher reliability can be obtained. This is because the compositions of the component (A) and the component (B) are optimized.
The optical waveguide 9 is obtained by the method for manufacturing an optical waveguide as described above.

(Second optical waveguide manufacturing method)
When manufacturing the optical waveguide 9 according to the third embodiment and the fourth embodiment, in addition to forming the shape of the core portion 94 in plan view by the above method, the core layer 93 in the longitudinal section by the following method is used. Shape the shape.

  Hereinafter, although the 2nd manufacturing method of an optical waveguide is explained, it is the same as that of the 1st manufacturing method except for forming the shape of core layer 93 in a longitudinal section.

  FIGS. 14 to 16 are perspective views schematically showing process examples of the second manufacturing method of the optical waveguide. 14 to 16 are drawn so as to pass through the core layer 93 and the cladding layer 92. In FIGS. 15 and 16, dots are added to the area corresponding to the core portion 94.

  First, as shown in FIG. 14A, a clad layer 91 is prepared. A predetermined step is formed on the upper surface of the cladding layer 91 in accordance with a change in the thickness of the core layer 93 to be manufactured. Here, a case where the optical waveguide 9 shown in FIG. 5C is manufactured will be described as an example. In the optical waveguide 9 shown in FIG. 5C, a thick film portion 943 is provided at the left end portion, and a thin film portion 944 is provided at the right end portion. On the other hand, the upper surface of the clad layer 91 moves up and down according to the thickness change of the core layer 93, while the lower surface is a horizontal smooth surface. In FIG. 14A, the clad layer 91 extended to both ends is prepared as a lower clad layer base material 91 '. The lower clad layer base material 91 ′ has a first surface 911 whose upper surface is gradually lowered to the left toward the left end portion at a position slightly moved to the right side from the left end surface in the longitudinal direction. And a second surface 912 that gradually increases to the left. Further, at a position slightly moved to the left side from the right end surface in the longitudinal direction, the third surface 913 whose upper surface gradually increases to the right toward the right end, and then gradually decreases to the right. And a fourth surface 914 that is lowered. Of these, the slopes of the top surfaces of the first surface 911 and the third surface 913 are the slopes of the bottom surface of the thick film portion 943 and the thin film portion 944 of the core layer 93 shown in FIG. 5C, respectively. Each corresponds. On the other hand, the degree of inclination of the upper surfaces of the second surface 912 and the fourth surface 914 is the same as that obtained by inverting the first surface 911 and the third surface 913, respectively. Moreover, the upper surfaces other than these surfaces are horizontal surfaces.

  Next, a varnish 900 is prepared by dissolving the photosensitive resin composition in a solvent, and this varnish 900 is applied onto the lower clad layer base material 91 ′. Thereafter, the film 910 is obtained through drying (see FIG. 14B).

  Next, the film 910 is selectively irradiated with light. At this time, as shown in FIG. 14C, a mask M having an opening formed thereon is disposed above the film 910, and the film 910 is irradiated with light through the opening. Thereby, a refractive index difference is generated between the irradiated region and the non-irradiated region. Here, the region irradiated with light becomes the clad portion 95, and the non-irradiated region becomes the core portion 94 (see FIG. 15D). As described above, the core layer 93 is formed on the film 910.

  Next, the obtained laminate of the film 910 and the lower clad layer base material 91 ′ is cut along two cut surfaces S shown in FIG. The two cut surfaces S are the boundary line between the first surface 911 and the second surface 912 provided on the upper surface of the lower clad layer base material 91 ′, and the third surface 913 and the fourth surface 912. Each of the surfaces is along a boundary line with the surface 914. By cutting the laminated body along the cut surface S, a laminated body of the (lower) clad layer 91 and the core layer 93 is obtained (see FIG. 15F).

  Next, as shown in FIG. 16G, a clad layer 92 is pasted on the core layer 93. Through the above steps, the optical waveguide 9 shown in FIG. 16 (h) is obtained.

  In the above description, the method of manufacturing the optical waveguide 9 shown in FIG. 5C has been described. However, when necessary, the top surface of the film 910 is formed (for example, machined) when the film 910 is dried. , Embossing, etc.) and drying. Thereby, the upper surface of the film 910 can be moved up and down, and the optical waveguide 9 shown in FIGS. 5A, 5B, and 5D can be manufactured.

  Further, the order of the steps is not limited to the above, and for example, the base material for forming the clad layer 92 may be attached and then cut along the cut surface S.

  Although the present invention has been described above, the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  Moreover, in the said embodiment, although the photosensitive resin composition was used and the optical waveguide film was formed, you may use for a hologram etc. not only in this. The above-mentioned photosensitive resin composition is suitable for forming a film in which a region having a high refractive index and a region having a low refractive index are mixed.

Next, examples of the present invention will be described.
A. Production of optical waveguide (Example 1)
(1) Synthesis of norbornene-based resin having a leaving group In a glove box filled with dry nitrogen in which the water and oxygen concentrations are both controlled to 1 ppm or less, 7.2 g (40.1 mmol) of hexylnorbornene (HxNB) ), 12.9 g (40.1 mmol) of diphenylmethylnorbornenemethoxysilane was weighed into a 500 mL vial, 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the top was sealed with a silicon sealer.

  Next, 1.56 g (3.2 mmol) of Ni catalyst represented by the following chemical formula (B) and 10 mL of dehydrated toluene are weighed in a 100 mL vial, put a stirrer chip and sealed, and the catalyst is thoroughly stirred to completely Dissolved in.

  When 1 mL of the Ni catalyst solution represented by the following chemical formula (B) is accurately weighed with a syringe, and quantitatively injected into the vial bottle in which the above two types of norbornene are dissolved, and stirred at room temperature for 1 hour, a marked increase in viscosity occurs. Was confirmed. At this point, the stopper was removed, 60 g of tetrahydrofuran (THF) was added, and the mixture was stirred to obtain a reaction solution.

  In a 100 mL beaker, 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (concentration 30%) and 30 g of ion-exchanged water were added and stirred to prepare an aqueous solution of peracetic acid on the spot. Next, the total amount of this aqueous solution was added to the above reaction solution and stirred for 12 hours to reduce Ni.

  Next, the treated reaction solution was transferred to a separatory funnel, the lower aqueous layer was removed, and then 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. The aqueous layer was removed after standing and completely separating the two layers. After repeating this water washing process three times in total, the oil layer was dropped into a large excess of acetone to reprecipitate the polymer produced, separated from the filtrate by filtration, and then in a vacuum dryer set at 60 ° C. Polymer # 1 was obtained by heating and drying for 12 hours. The molecular weight distribution of the polymer # 1 was Mw = 100,000 and Mn = 40,000 by GPC measurement. Moreover, the molar ratio of each structural unit in the polymer # 1 was 50 mol% for the hexylbornene structural unit and 50 mol% for the diphenylmethylnorbornenemethoxysilane structural unit, as determined by NMR. The refractive index was 1.55 (measurement wavelength: 633 nm) by Metricon.

(2) Production of photosensitive resin composition 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyl oxetane monomer (formula 20) First monomer represented by (Formula 100), Toa Gosei CHOX, CAS # 483303-25-9, molecular weight 186, boiling point 125 ° C./1.33 kPa) 2 g, photoacid generator Rhodorsil Photoinitiator 2074 (manufactured by Rhodia, CAS #) 178233-72-2) (1.36E-2 g in 0.1 mL of ethyl acetate) and uniformly dissolved, and then filtered through a 0.2 μm PTFE filter to obtain a clean photosensitive resin composition varnish V1. It was.

(3) Production of optical waveguide film (production of lower clad layer)
A photosensitive norbornene resin composition (Avatrel 2000P varnish manufactured by Promeras Co., Ltd.) was uniformly applied on a silicon wafer with a doctor blade, and then placed in a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, the entire coated surface was irradiated with 100 mJ of ultraviolet light and heated in a dryer at 120 ° C. for 1 hour to cure the coating film to form a lower clad layer. The formed lower cladding layer had a thickness of 20 μm, was colorless and transparent, and had a refractive index of 1.52 (measurement wavelength: 633 nm).

(Formation of core layer)
After the photosensitive resin composition varnish V1 was uniformly applied on the lower clad layer with a doctor blade, it was put into a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, a photomask was pressed and selectively irradiated with ultraviolet rays at 500 mJ / cm ² . The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating. Moreover, formation of the core part and the clad part was confirmed.

(Formation of upper cladding layer)
A dry film in which Avatrel 2000P is laminated in advance on a polyethersulfone (PES) film so as to have a dry thickness of 20 μm is bonded to the above core layer, and put into a vacuum laminator set at 140 ° C. for thermocompression bonding. It was. Thereafter, 100 mJ was irradiated on the entire surface and heated in a dryer at 120 ° C. for 1 hour to cure Avatrel 2000P to form an upper clad layer to obtain an optical waveguide. At this time, the upper cladding layer was colorless and transparent, and its refractive index was 1.52.

(4) Evaluation (Evaluation of optical waveguide loss)
Light emitted from an 850 nm VCSEL (surface emitting laser) was introduced into the optical waveguide via a 50 μmφ optical fiber, received by a 200 μmφ optical fiber, and the light intensity was measured. The cutback method was used for the measurement. When the longitudinal direction of the optical waveguide is taken on the horizontal axis and the insertion loss is plotted on the vertical axis, the measured values are neatly arranged on a straight line, and the propagation loss can be calculated as 0.03 dB / cm from the inclination. .

(Refractive index difference between core and clad)
The refractive index difference between the left and right core portions and the clad portion adjacent in the horizontal direction formed in the above (formation of the core layer) was determined as follows.

  Optical waveguide analyzer OWA-9500 manufactured by EXFO, Canada was used to irradiate the optical waveguide with laser light having a wavelength of 656 nm, and the refractive indexes of the core region and the cladding region were measured, and the difference between them was calculated. As a result, the refractive index difference was 0.02.

(Example 2)
(1) Synthesis of norbornene-based resin having no leaving group In a glove box filled with dry nitrogen in which the water and oxygen concentrations are both controlled to 1 ppm or less, 9.4 g of hexylnorbornene (HxNB) (53. 1 mmol) and 10.5 g (53.1 mmol) of phenylethylnorbornene were weighed into a 500 mL vial, 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the top was sealed with a silicon sealer.

  Next, weigh 2.06 g (3.2 mmol) of Ni catalyst represented by the above chemical formula (B) and 10 mL of dehydrated toluene in a 100 mL vial, put a stirrer chip and seal tightly, and thoroughly stir the catalyst. Dissolved in.

  When 1 mL of the Ni catalyst solution represented by the chemical formula (B) is accurately weighed with a syringe, and quantitatively injected into the vial bottle in which the two types of norbornene are dissolved and stirred at room temperature for 1 hour, a marked increase in viscosity is observed. confirmed. At this point, the stopper was removed, 60 g of tetrahydrofuran (THF) was added, and the mixture was stirred to obtain a reaction solution.

  In a 100 mL beaker, 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (concentration 30%) and 30 g of ion-exchanged water were added and stirred to prepare an aqueous solution of peracetic acid on the spot. Next, the total amount of this aqueous solution was added to the above reaction solution and stirred for 12 hours to reduce Ni.

  Next, the treated reaction solution was transferred to a separatory funnel, the lower aqueous layer was removed, and then 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. The aqueous layer was removed after standing and completely separating the two layers. After repeating this water washing process three times in total, the oil layer was dropped into a large excess of acetone to reprecipitate the polymer produced, separated from the filtrate by filtration, and then in a vacuum dryer set at 60 ° C. Polymer # 2 was obtained by heat drying for 12 hours. The molecular weight distribution of the polymer # 2 was Mw = 90,000 and Mn = 40,000 by GPC measurement. The molar ratio of each structural unit in polymer # 2 was 50 mol% for the hexylbornene structural unit and 50 mol% for the phenylethylnorbornene structural unit, as determined by NMR. The refractive index was 1.54 (measurement wavelength: 633 nm) by Metricon.

(2) Production of photosensitive resin composition 10 g of the purified polymer # 2 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of an antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyloxetane monomer (formula 20) 2 g, photoacid generator Rhodorsil Photoinitiator 2074 (manufactured by Rhodia, CAS # 178233-72-2), manufactured by Toa Gosei Co., Ltd. CHOX, CAS # 48333-3-25-9, molecular weight 186, boiling point 125 ° C./1.33 kPa) (1.36E-2 g, in 0.1 mL of ethyl acetate) was added and dissolved uniformly, and then filtered through a 0.2 μm PTFE filter to obtain a clean photosensitive resin composition varnish V2.

(3) Production of optical waveguide film (production of lower clad layer)
A lower clad layer similar to that in Example 1 was produced.

(Formation of core layer)
After the photosensitive resin composition varnish V2 was uniformly applied on the lower clad layer with a doctor blade, it was put into a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, a photomask was pressed and selectively irradiated with ultraviolet rays at 500 mJ / cm ² . The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating. Moreover, formation of the core part and the clad part was confirmed.

(Formation of upper cladding layer)
An upper clad layer similar to that in Example 1 was produced.

(4) Evaluation Evaluation was performed in the same manner as in Example 1. The propagation loss could be calculated as 0.04 dB / cm. The difference in refractive index between the core portion and the cladding portion was 0.01.

(Example 3)
(1) Synthesis of norbornene-based resin having a leaving group A norbornene-based resin was produced in the same manner as in Example 1.

(2) Production of photosensitive resin composition 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, an antioxidant Irganox 1076 (manufactured by Ciba Geigy) 0.01 g, a bifunctional oxetane monomer (formula (15), manufactured by Toa Gosei Co., Ltd., DOX, CAS # 18934-00-4, molecular weight 214, boiling point 119 ° C./0.67 kPa) 2 g, photoacid generator Rhodosil Photoinitiator 2074 (manufactured by Rhodia Co., CAS # 178233-) 72-2) (1.36E-2 g in 0.1 mL of ethyl acetate) was added and dissolved uniformly, and then filtered through a 0.2 μm PTFE filter to obtain a clean photosensitive resin composition varnish V3.

(3) Production of optical waveguide film (production of lower clad layer)
A lower clad layer similar to that in Example 1 was produced.

(Formation of core layer)
After the photosensitive resin composition varnish V3 was uniformly applied on the lower clad layer with a doctor blade, it was put into a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, a photomask was pressed and selectively irradiated with ultraviolet rays at 500 mJ / cm ² . The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating. Moreover, formation of the core part and the clad part was confirmed.

(Formation of upper cladding layer)
An upper clad layer similar to that in Example 1 was produced.

(4) Evaluation Evaluation was performed in the same manner as in Example 1. The propagation loss could be calculated as 0.04 dB / cm. The difference in refractive index between the core portion and the cladding portion was 0.01.

Example 4
(1) Synthesis of norbornene-based resin having a leaving group A norbornene-based resin was produced in the same manner as in Example 1.

(2) Production of photosensitive resin composition 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of an antioxidant Irganox 1076 (manufactured by Ciba Geigy), an alicyclic epoxy monomer ( Formula (37), manufactured by Daicel Chemical Industries, Celoxide 2021P, CAS # 2386-87-0, molecular weight 252, boiling point 188 ° C./4 hPa) 2 g, photoacid generator Rhodorsil Photoinitiator 2074 (manufactured by Rhodia, CAS # 178233-) 72-2) (1.36E-2 g in 0.1 mL of ethyl acetate) was added and dissolved uniformly, and then filtered through a 0.2 μm PTFE filter to obtain a clean photosensitive resin composition varnish V4.

(3) Production of optical waveguide film (production of lower clad layer)
A lower clad layer similar to that in Example 1 was produced.

(Formation of core layer)
After the photosensitive resin composition varnish V4 was uniformly applied on the lower clad layer with a doctor blade, it was put into a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, a photomask was pressed and selectively irradiated with ultraviolet rays at 500 mJ / cm ² . The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating. Moreover, formation of the core part and the clad part was confirmed.

(Formation of upper cladding layer)
An upper clad layer similar to that in Example 1 was produced.

(4) Evaluation Evaluation was performed in the same manner as in Example 1. The propagation loss could be calculated as 0.04 dB / cm. The difference in refractive index between the core portion and the cladding portion was 0.01.

(Example 5)
(1) Synthesis of norbornene-based resin having a leaving group A norbornene-based resin was produced in the same manner as in Example 1.

(2) Production of photosensitive resin composition 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyl oxetane monomer (formula 20) 1 g of CHOX manufactured by Toagosei Co., Ltd. 1 g of alicyclic epoxy monomer (manufactured by Daicel Chemical Industries, Celoxide 2021P), photoacid generator Rhodosil Photoinitiator 2074 (manufactured by Rhodia, CAS # 178233-72-2) (1.36E- 2 g in 0.1 mL of ethyl acetate) and uniformly dissolved, and then filtered through a 0.2 μm PTFE filter to obtain a clean photosensitive resin composition varnish V5.

(3) Production of optical waveguide film (production of lower clad layer)
A lower clad layer similar to that in Example 1 was produced.

(Formation of core layer)
After the photosensitive resin composition varnish V5 was uniformly applied on the lower clad layer with a doctor blade, it was put into a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, a photomask was pressed and selectively irradiated with ultraviolet rays at 500 mJ / cm ² . The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating. Moreover, formation of the core part and the clad part was confirmed.

(Formation of upper cladding layer)
An upper clad layer similar to that in Example 1 was produced.

(4) Evaluation Evaluation was performed in the same manner as in Example 1. The propagation loss could be calculated as 0.03 dB / cm. The difference in refractive index between the core portion and the cladding portion was 0.01.

(Example 6)
(1) Synthesis of norbornene-based resin having a leaving group A norbornene-based resin was produced in the same manner as in Example 1.

(2) Production of photosensitive resin composition 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyl oxetane monomer (formula 20) And 1.5 g of a photoacid generator, Rhodosil Photoinitiator 2074 (manufactured by Rhodia, CAS # 178233-72-2) (1.36E-2 g in 0.1 mL of ethyl acetate) and uniformly added. After dissolution, filtration was performed with a 0.2 μm PTFE filter to obtain a clean photosensitive resin composition varnish V6.

(3) Production of optical waveguide film (production of lower clad layer)
A lower clad layer similar to that in Example 1 was produced.

(Formation of core layer)
After the photosensitive resin composition varnish V6 was uniformly applied on the lower clad layer with a doctor blade, it was put into a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, a photomask was pressed and selectively irradiated with ultraviolet rays at 500 mJ / cm ² . The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating. Moreover, formation of the core part and the clad part was confirmed.

(Formation of upper cladding layer)
An upper clad layer similar to that in Example 1 was produced.

(4) Evaluation Evaluation was performed in the same manner as in Example 1. The propagation loss could be calculated as 0.03 dB / cm. The difference in refractive index between the core portion and the cladding portion was 0.01.

(Example 7)
(1) Synthesis of norbornene-based resin having a leaving group In a glove box whose water and oxygen concentrations are both controlled to 1 ppm or less and filled with dry nitrogen, 6.4 g (36.1 mmol) of hexylnorbornene (HxNB) ), Diphenylmethylnorbornene methoxysilane (diPhNB) 8.7 g (27.1 mmol), epoxy norbornene (EpNB) 4.9 g (27.1 mmol) were weighed into a 500 mL vial, 60 g of dehydrated toluene and 11 g of ethyl acetate were added, The top was sealed with a silicon sealer.

  Next, 1.75 g (3.2 mmol) of the Ni catalyst represented by the above chemical formula (B) and 10 mL of dehydrated toluene are weighed in a 100 mL vial, put a stirrer chip and sealed, and the catalyst is thoroughly stirred to completely Dissolved in.

  When 1 mL of the Ni catalyst solution represented by the above chemical formula (B) is accurately weighed with a syringe, and quantitatively injected into the vial bottle in which the three types of norbornene are dissolved, and stirred at room temperature for 1 hour, a marked increase in viscosity occurs. Was confirmed. At this point, the stopper was removed, 60 g of tetrahydrofuran (THF) was added, and the mixture was stirred to obtain a reaction solution.

  In a 100 mL beaker, 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (concentration 30%) and 30 g of ion-exchanged water were added and stirred to prepare an aqueous solution of peracetic acid on the spot. Next, the total amount of this aqueous solution was added to the above reaction solution and stirred for 12 hours to reduce Ni.

  Next, the treated reaction solution was transferred to a separatory funnel, the lower aqueous layer was removed, and then 100 mL of a 30% aqueous solution of isopropyl alcohol isopropyl alcohol was added and vigorously stirred. The aqueous layer was removed after standing and completely separating the two layers. After repeating this water washing process three times in total, the oil layer was dropped into a large excess of acetone to reprecipitate the polymer produced, separated from the filtrate by filtration, and then in a vacuum dryer set at 60 ° C. Polymer # 3 was obtained by heat drying for 12 hours. The molecular weight distribution of the polymer # 3 was Mw = 80,000 and Mn = 40,000 by GPC measurement. The molar ratio of each structural unit in polymer # 3 was 40 mol% for hexylbornene structural unit, 30 mol% for diphenylmethylnorbornenemethoxysilane structural unit, and 30 mol% for epoxynorbornene structural unit, as determined by NMR. It was. The refractive index was 1.53 (measurement wavelength: 633 nm) by Metricon.

(2) Production of photosensitive resin composition 10 g of the purified polymer # 3 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyloxetane monomer (formula 20) 1), CHOX manufactured by Toa Gosei Co., Ltd., and photoacid generator Rhodosil Photoinitiator 2074 (manufactured by Rhodia, CAS # 178233-72-2) (1.36E-2 g, in 0.1 mL of ethyl acetate) are uniformly added. After dissolution, filtration was performed with a 0.2 μm PTFE filter to obtain a clean photosensitive resin composition varnish V7.

(3) Production of optical waveguide film (production of lower clad layer)
A lower clad layer similar to that in Example 1 was produced.

(Formation of core layer)
After the photosensitive resin composition varnish V7 was uniformly applied on the lower clad layer with a doctor blade, it was put into a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, a photomask was pressed and selectively irradiated with ultraviolet rays at 500 mJ / cm ² . The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating. Moreover, formation of the core part and the clad part was confirmed.

(Formation of upper cladding layer)
An upper clad similar to that of Example 1 was produced.

(4) Evaluation Evaluation was performed in the same manner as in Example 1. The propagation loss could be calculated as 0.04 dB / cm. The refractive index difference between the core portion and the clad portion was 0.02.
The evaluation results of the optical waveguide films obtained in Examples 1 to 7 are shown in Table 1 above.

In Examples 1 to 7, when light is applied to the photosensitive resin composition, an acid is generated from the photoacid generator, and a monomer having a cyclic ether group is polymerized only in the irradiated portion. Then, since the amount of unreacted monomer in the irradiated part decreases, the monomer in the unirradiated part diffuses into the irradiated part in order to eliminate the concentration gradient generated between the irradiated part / unirradiated part.
Further, when heating is performed after light irradiation, the monomer volatilizes from the unirradiated portion.

  As described above, the structure concentration derived from the monomer is different between the core portion and the cladding portion, the structure derived from the monomer having a cyclic ether group increases in the cladding portion, and the monomer derived from the monomer having a cyclic ether group is present in the core portion. There are fewer structures. This is recognized from the fact that a relatively large refractive index difference of 0.01 or more occurs between the core portion and the cladding portion.

  In Examples 1 to 7, a linear optical waveguide is formed. However, when a curved optical waveguide (with a radius of curvature of about 10 mm) is formed, it is remarkable that optical loss is small.

  Furthermore, the optical waveguide films obtained in Examples 1 to 7 have high heat resistance and have reflow resistance of 260 ° C.

(Example 8)
(1) Synthesis of norbornene resin having a leaving group In the synthesis of a norbornene resin having a leaving group, phenyldimethylnorbornenemethoxysilane was used instead of 12.9 g (40.1 mmol) of diphenylmethylnorbornenemethoxysilane. Example 1 was repeated except that 4 g (40.1 mmol) was used. The molecular weight of the obtained norbornene resin B (Formula 103) having a leaving group in the side chain was Mw = 110,000 and Mn = 50,000 by GPC measurement. The molar ratio of each structural unit was 50 mol% for the hexylnorbornene structural unit and 50 mol% for the phenyldimethylnorbornenemethoxysilane structural unit, as determined by NMR. The refractive index was 1.53 (measurement wavelength: 633 nm) by Metricon.

(2) Production of photosensitive resin composition A photosensitive resin composition was obtained in the same manner as in Example 1 except that the norbornene resin B was used instead of the polymer # 1.

(3) Production of optical waveguide film An optical waveguide film was obtained in the same manner as in Example 1 except that the photosensitive resin composition containing the norbornene-based resin B was used.

  When the loss evaluation of the optical waveguide was performed in the same manner as in Example 1, the propagation loss of the obtained optical waveguide film was 0.03 dB / cm.

Example 9
(1) The procedure was the same as Example 1 except that the following photosensitive resin composition was used.

  10 g of norbornene-based resin obtained in Example 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of an antioxidant Irganox 1076 (manufactured by Ciba Geigy), and a cyclohexyloxetane monomer (formula (100) represented by formula (100)). 1 monomer, manufactured by Toa Gosei CHOX, CAS # 483303-25-9, molecular weight 186, boiling point 125 ° C./1.33 kPa) 1 g, bifunctional oxetane monomer (second monomer represented by formula (104), manufactured by Toa Gosei, DOX , CAS # 18934-00-4, molecular weight 214, boiling point 119 ° C./0.67 kPa) 1 g, photoacid generator Rhodosil Photoinitiator 2074 (manufactured by Rhodia, CAS # 178233-72-2) (1.36E-2 g, ethyl acetate In 0.1 mL) After dissolving one was filtered through 0.2 [mu] m PTFE filter to prepare a photosensitive resin composition varnish for clean core layer.

(2) Production of optical waveguide film An optical waveguide film was obtained in the same manner as in Example 1 except that the photosensitive resin composition of (1) above was used.

  When the loss evaluation of the optical waveguide was performed in the same manner as in Example 1, the propagation loss of the obtained optical waveguide film was 0.04 dB / cm.

(Example 10)
Example 1 was repeated except that the following were used as the cyclic olefin.

(1) Synthesis of norbornene-based resin C Norbornene represented by the following formula (105) is obtained by performing ring-opening metathesis polymerization of phenylethylnorbornene (PENB) monomer using a known method (for example, JP-A-2003-252963). System resin C was obtained.

(2) Production of photosensitive resin composition A photosensitive resin composition was obtained in the same manner as in Example 1 except that the norbornene resin C was used instead of the polymer # 1.

(3) Production of optical waveguide film An optical waveguide film was obtained in the same manner as in Example 1 except that the photosensitive resin composition containing the norbornene-based resin C was used.

  When the loss evaluation of the optical waveguide was performed in the same manner as in Example 1, the propagation loss of the obtained optical waveguide film was 0.05 dB / cm.

(Example 11)
An optical waveguide film was produced in the same manner as in Example 1 except that the amount of the first monomer was changed to 0.5 g.
The propagation loss of the obtained optical waveguide film was 0.10 dB / cm.

(Example 12)
An optical waveguide film was produced in the same manner as in Example 1 except that the blending amount of the first monomer was 4.0 g.
The propagation loss of the obtained optical waveguide film was 0.10 dB / cm.

(Comparative Example 1)
An optical waveguide film was produced in the same manner as in Example 1 except that the first monomer was not used.
The propagation loss of the obtained optical waveguide film was 0.90 dB / cm.

(Comparative Example 2)
(1) Synthesis of each component <Catalyst precursor: Synthesis of Pd (OAc) ₂ (P (Cy) ₃ ) ₂ >
In a 2-neck round bottom flask equipped with a funnel, a reddish brown suspension consisting of Pd (OAc) ₂ (5.00 g, 22.3 mmol) and CH ₂ Cl ₂ (30 mL) was stirred at −78 ° C.

A funnel was charged with a CH ₂ Cl ₂ solution (30 mL) of P (Cy) ₃ (13.12 mL (44.6 mmol)) and added dropwise to the stirred suspension over 15 minutes. As a result, the color gradually changed from reddish brown to yellow.

  After stirring at −78 ° C. for 1 hour, the suspension was warmed to room temperature, stirred for an additional 2 hours, and diluted with hexane (20 mL).

  The yellow solid was then filtered in air, washed with pentane (5 × 10 mL) and dried in vacuo.

  The secondary collection was separated by cooling the filtrate to 0 ° C., washed and dried as above. As a result, a catalyst precursor was obtained.

(2) Production of photosensitive resin composition 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, 40 g of mesitylene, 0.01 g of an antioxidant Irganox 1076 (manufactured by Ciba Geigy), and dimethylbis (norbornenemethoxy). Silane (SiX) 2.4g, the above catalyst precursor (2.6E-2g), photoacid generator Rhodosil Photoinitiator 2074 (manufactured by Rhodia, CAS # 178233-72-2) (1.36E-2g, in ethyl acetate 0.1mL) ) And uniformly dissolved, followed by filtration with a 0.2 μm PTFE filter to obtain a clean photosensitive resin composition varnish.

(3) Production of optical waveguide film (production of lower clad layer)
A lower clad layer similar to that in Example 1 was produced.

(Formation of core layer)
The varnish prepared on the lower clad layer was uniformly applied by a doctor blade, and then placed in a 45 ° C. dryer for 15 minutes. After completely removing the solvent, a photomask was pressed and selectively irradiated with ultraviolet rays at 500 mJ / cm ² . The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a waveguide pattern appeared after heating. Moreover, formation of the core part and the clad part was confirmed.

(Formation of upper cladding layer)
An upper clad layer similar to that in Example 1 was produced.

(4) Evaluation Evaluation was performed in the same manner as in Example 1. The propagation loss could be calculated as 0.05 dB / cm. The difference in refractive index between the core portion and the cladding portion was 0.005.

B. Evaluation of Optical Waveguide The following evaluations were performed on the optical waveguides obtained in the examples and comparative examples. The evaluation items are shown together with the contents. The obtained results are shown in Table 2.

1. Light loss Light emitted from an 850 nm VCSEL (surface emitting laser) was introduced into the optical waveguide via a 50 μmφ optical fiber, and received by a 200 μmφ optical fiber to measure the light intensity. The cutback method was used for the measurement, and the waveguide length was plotted on the horizontal axis and the insertion loss was plotted on the vertical axis. The measured values were neatly arranged on a straight line, and the propagation loss was calculated from the slope.

2. Heat resistance The optical waveguide was placed in a high-temperature and high-humidity tank (85 ° C., 85% RH), and propagation loss after 500 hours of wet heat treatment was evaluated. It was also confirmed in parallel presence or absence of degradation of the propagation loss due to reflow process (N ₂ atmosphere, a maximum temperature of 260 ° C. / 60 seconds).
Note that the measurement of the propagation loss here is the same as the one optical loss measurement method.

3. Bending loss of optical waveguide The bending loss of the light intensity of the optical waveguide film having a radius of curvature of 10 mm was evaluated. Light emitted from an 850 nm VCSEL (surface emitting laser) was introduced into the end face of the optical waveguide film via a 50 μmφ optical fiber, and the light intensity was measured from the other end with a 200 μmφ optical fiber (see the following formula) ). The increment of the loss that occurs when the optical waveguide film having the same length is bent is defined as “bending loss”. As shown in FIG. 17, the insertion loss and the optical waveguide film are linear when the optical waveguide film is curved. The “bending loss” is expressed by the difference from the insertion loss when the shape is made.

Insertion loss [dB] =-10 log (emitted light intensity / incident light intensity)
Bending loss = (insertion loss in a curve)-(insertion loss in a straight line)

  As is apparent from Table 2, Examples 1 and 8-12 showed low optical loss and excellent optical waveguide performance.

  Moreover, Examples 1 and 8-12 showed that the light loss after a high-temperature, high-humidity process and a reflow process was also small, and it was excellent also in heat resistance.

  In particular, Examples 1, 8, 9, and 10 have a small bending loss, and it was suggested that sufficient performance was exhibited even when the optical waveguide was bent.

  Furthermore, when the optical waveguide structure according to the first embodiment was produced using the optical waveguide film obtained in each example and comparative example, the optical waveguide using the optical waveguide film obtained in each example was produced. A structure having a low transmission loss was obtained as compared with the optical waveguide structure using the optical waveguide film obtained in each comparative example.

  That is, when an optical waveguide film having a widened portion and a reduced width portion was produced by the same method as each example and comparative example, the width of the core portion produced by the same method as each example and comparative example was A reduction in light loss was observed compared to a constant optical waveguide film.

  Similarly, when an optical waveguide film having a thick film portion and a thin film portion was produced by the same method as in each example and comparative example, a decrease in light loss was also observed.

DESCRIPTION OF SYMBOLS 1 Optical waveguide structure 2 Board | substrate 21 Through-hole 22 Conductor post 3 Light emitting element 30 Base 31 Light emitting part 32 Metal wire 33 External electrode 34 Resin mold 35 Light emitting IC (light emitting electric element)
300 light emitting circuit 4 light receiving element 40 base 41 light receiving part 42 metal wire 43 external electrode 44 resin mold 45 light receiving IC (light receiving electric element)
400 light receiving circuit 5 conductor layer 51 electric wiring 9 optical waveguide 91 clad layer 91 ′ base material for lower clad layer 911 first surface 912 second surface 913 third surface 914 fourth surface 92 clad layer 93 core layer 94 Core portion 940 Equal width portion 941, 941 ′ Widened portion (extended portion)
942, 942 'Reduced portion (reduced portion)
943, 943 'Thick film part (expanded part)
944, 944 'Thin film part (reduced part)
945 Equal thickness portion 95 Clad portion 971, 972 Optical path changing portion 98 Optical wiring 900 Varnish 910 Film M Mask S Cut surface

Claims (34)

An optical waveguide having a core part and a clad part having different refractive indexes from each other,
The core portion has an extended portion whose cross-sectional area continuously increases toward one end portion, and
(A) a cyclic olefin resin;
(B) The refractive index is different from that of (A), and at least one of a monomer having a cyclic ether group and an oligomer having a cyclic ether group;
(C) a photoacid generator;
An optical waveguide structure characterized by being formed into a desired shape by selectively irradiating active radiation to a core layer composed of a composition comprising:   The optical waveguide structure according to claim 1, wherein the cyclic ether group (B) is an oxetanyl group or an epoxy group.   The optical waveguide structure according to claim 1 or 2, wherein the cyclic olefin resin (A) is a norbornene resin. (B) has a lower refractive index than (A),
2. The cyclic olefin resin has a leaving group that is detached by an acid generated from the photoacid generator (C) and lowers the refractive index of (A) by the elimination. 4. The optical waveguide structure according to any one of 3 above. The cyclic olefin resin (A) has a leaving group that is eliminated by an acid generated from the photoacid generator (C) in the side chain,
The optical waveguide structure according to claim 2, wherein (B) includes the first monomer represented by the following formula (100).

  6. The optical waveguide structure according to claim 5, wherein (B) further contains at least one of the epoxy compound and the oxetane compound having two oxetanyl groups as a second monomer.   The optical waveguide according to claim 6, wherein a ratio of the second monomer to the first monomer is 0.1 to 1.0 in a weight ratio (weight of the second monomer / weight of the first monomer). Structure.   The optical waveguide structure according to claim 4, wherein the leaving group has at least one of an —O— structure, an —Si—aryl structure, and an —O—Si— structure. .   9. The optical waveguide structure according to claim 5, wherein the cyclic olefin resin (A) is a norbornene resin.   The optical waveguide structure according to claim 9, wherein the norbornene-based resin is an addition polymer of norbornene. The optical waveguide structure according to claim 10, wherein the addition polymer of norbornene has a repeating unit represented by the following formula (101).

[N in the formula is an integer of 0 or more and 9 or less. ] The optical waveguide structure according to claim 10 or 11, wherein the norbornene addition polymer has a repeating unit represented by the following formula (102).

  The optical waveguide according to any one of claims 5 to 12, wherein the content of the first monomer represented by the formula (100) is 1 part by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the cyclic olefin resin. Structure.   The optical waveguide structure according to any one of claims 1 to 13, wherein the concentration of the structure derived from (B) is different between a region irradiated with active radiation of the core layer and a non-irradiated region.   The optical waveguide structure according to any one of claims 1 to 14, wherein a difference in refractive index between an area irradiated with active radiation and an unirradiated area of the core layer is 0.01 or more.   The optical waveguide structure according to any one of claims 1 to 15, wherein a region of the core layer irradiated with actinic radiation is at least a part of the cladding part, and an unirradiated region is at least a part of the core part.   The optical waveguide structure according to any one of claims 1 to 16, wherein, in the extended portion, a width of the core portion in a plan view continuously increases toward one end of the optical waveguide.   The optical waveguide structure according to any one of claims 1 to 17, wherein a thickness of the core portion is continuously increased toward one end portion of the optical waveguide in the extended portion.   2. The extended portion has the core portion formed such that a boundary line between the core portion and the clad portion in plan view is along a parabola that opens toward one end portion of the optical waveguide. The optical waveguide structure according to any one of Items 18 to 18.   In the extended portion, the core portion is configured such that a boundary line between the core portion and the cladding portion in a plan view or a boundary line between the core portion and the cladding portion in the thickness direction is the one end of the core portion. The optical waveguide structure according to any one of claims 1 to 19, wherein the optical waveguide structure forms an angle of not less than 45 degrees and less than 90 degrees with respect to an end face of the portion.   21. The optical waveguide structure according to claim 1, wherein an area of an end surface of the one end portion of the core portion is larger than an area of an end surface of the other end portion.   The optical waveguide structure according to any one of claims 1 to 21, wherein a width of the one endmost portion of the core portion in plan view is larger than a width of the other endmost portion in plan view.   23. The optical waveguide structure according to claim 1, wherein a thickness of the one endmost portion of the core portion is larger than a thickness of the other endmost portion.   24. The core according to claim 1, further comprising a reduced portion that is provided closer to the other end than the extended portion, and whose cross-sectional area continuously decreases toward the other end. 2. An optical waveguide structure according to 1.   25. The optical waveguide structure according to claim 24, wherein a width of the core portion in plan view continuously decreases toward the other end of the optical waveguide in the reduced portion.   The optical waveguide structure according to claim 24 or 25, wherein a thickness of the core portion is continuously reduced toward the other end of the optical waveguide in the reduced portion.   25. In the reduced portion, the core portion is formed such that a boundary line between the core portion and the clad portion in a plan view is along a parabola that opens toward one end portion of the optical waveguide. 27. An optical waveguide structure according to any one of items 26 to 26.   In the reduced portion, the core portion is a boundary line between the core portion and the cladding portion in a plan view or a boundary line between the core portion and the cladding portion in the thickness direction is the one end of the core portion. The optical waveguide structure according to any one of claims 24 to 27, wherein the optical waveguide structure forms an angle of 45 degrees or more and less than 90 degrees with respect to an end face of the portion.   The optical waveguide structure according to any one of claims 1 to 28, wherein the optical waveguide includes a plurality of the core portions. The plurality of core portions are provided in parallel,
30. The optical waveguide structure according to claim 29, wherein at least two of the plurality of core portions adjacent to each other are at least one of a position of one end and a position of the other end shifted in the longitudinal direction. .   The position of the said one edge part and the position of the said other edge part are comprised so that it may become a mutually opposite position in at least 2 adjacent among these core parts. 2. An optical waveguide structure according to 1. The optical waveguide has an optical path conversion part that bends the optical path,
32. The optical path conversion unit according to any one of claims 1 to 31, wherein the optical path conversion unit is configured to bend light from the outside and guide the light to the core unit, or to bend and guide light transmitted through the core unit to the outside. Optical waveguide structure.   35. The wiring board according to claim 1, further comprising: a wiring board provided on at least one surface of the optical waveguide, and a substrate and a conductor layer provided on at least one surface of the optical waveguide and provided with electrical wiring. The optical waveguide structure according to any one of the above.   An electronic apparatus comprising the optical waveguide structure according to any one of claims 1 to 33.

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