WO2011125799A1 - Optical waveguide structure and electronic apparatus - Google Patents

Abstract

Disclosed is an optical waveguide structure that has a wide degree of freedom of pattern shape design, can form a core section (light path) having high dimensional precision via a simple method, and has excellent durability. Further disclosed is an electronic apparatus provided with the aforementioned optical waveguide structure. One embodiment of the present disclosures is cited below. The optical waveguide structure (1) is provided with: an optical waveguide body (2) that forms a block shape; and five light-emitting elements (61-65). The optical waveguide body (2) is formed from a plurality of cladding layers and a plurality of core layers being laminated in a predetermined order. In each core layer, a predetermined pattern of core sections (94) and cladding sections (95) is formed. The core sections (94) are portions that form a light path for transmitted light, and are three-dimensionally disposed within the optical waveguide body (2). The core sections (94) have as a primary material a resin composition containing, for example, a norbornene resin, and are formed to a desired shape by selectively radiating actinic radiation to the core layer (93) configured from a material of which the refractive index changes by means of irradiation by actinic radiation and also by means of heating.

Description

Optical waveguide structure and electronic device

The present invention relates to an optical waveguide structure and an electronic device.
This application claims priority based on Japanese Patent Application No. 2010-089402 filed in Japan on April 8, 2010, the contents of which are incorporated herein by reference.

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 versatile, in addition to conventional quartz optical waveguides. Has been actively conducted.

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 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. In particular, since the arrangement of the optical path (core part) is planar, the degree of freedom in designing the optical path is narrow.
2. The core pattern shape accuracy and dimensional accuracy are poor.
3. When combined with a wiring pattern, the degree of freedom in designing the wiring pattern is narrow.

JP 2004-146602 A

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical waveguide structure having an optical waveguide with a wide degree of freedom in designing a pattern shape and capable of forming a core portion (optical path) with high dimensional accuracy by a simple method. To provide a body. Moreover, it is providing the electronic device provided with the said optical waveguide structure.

Such an object is achieved by the present inventions (1) to (36) below.
(1) having an optical waveguide body having a core part forming an optical path and a clad part formed on the outer periphery of the core part and having a refractive index different from that of the core part;
The core portion is three-dimensionally arranged in the optical waveguide body,
The core part is
(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 has any one of the above (5) to (7) having 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.
(11) The optical waveguide structure according to (10), wherein the norbornene addition polymer has a repeating unit represented by the following formula (101).

(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 optical waveguide according to any one of (1) to (16), wherein the core portion has a portion extending in at least one of the X, Y, and Z directions orthogonal to each other. Structure.
(18) The optical waveguide according to any one of (1) to (16), wherein the core portion includes a portion extending in at least two of the X, Y, and Z directions orthogonal to each other. Structure.
(19) The optical waveguide structure according to any one of (1) to (18), wherein the optical waveguide body has a portion in which a clad layer and a core layer constituting the clad portion are alternately laminated.
(20) The optical waveguide body has any one of the above (1) to (19) having a portion in which two or more laminated bodies each formed by joining the clad layers constituting the clad portion are laminated on both surfaces of the core layer. An optical waveguide structure according to claim 1.
(21) The optical waveguide structure according to any one of (1) to (20), wherein the optical waveguide main body includes a core layer stacked portion in which a plurality of the core layers are stacked.
(22) The optical waveguide structure according to any one of (8) to (21), including a portion configured to transmit and receive transmission light between the core portions formed between different core layers. .
(23) The optical waveguide structure according to any one of (1) to (22), further including an optical path conversion unit that bends an optical path of transmission light transmitted through the core unit.
(24) The optical waveguide structure according to (23), wherein the optical path conversion unit has a reflection surface that reflects at least a part of the transmission light.
(25) The optical waveguide structure according to (23) or (24), wherein the optical path conversion unit has a function of dividing an optical path of the transmission light in a plurality of directions.
(26) The said core part is arrange | positioned so that the transmission light which injects into the predetermined site | part of the said core part from the outside of the said optical waveguide main body may not cross | intersect the other site | part of a core part. 25) The optical waveguide structure according to any one of 25).
(27) The optical waveguide structure according to any one of (1) to (26), wherein the core portion includes a portion where an optical path branches and / or merges.
(28) When transmission light is incident on a predetermined part of the core part from one incident direction among X, Y, and Z directions orthogonal to each other, the transmission light is transmitted from another part of the core part to the incident direction. The optical waveguide structure according to any one of (1) to (27), wherein the optical waveguide structure is configured to emit in an orthogonal direction.
(29) The optical waveguide structure according to any one of (1) to (28), wherein the optical waveguide body is configured with an inclined surface having at least one surface inclined with respect to a transverse section of the core portion. .
(30) The optical waveguide structure according to any one of (1) to (29), wherein the optical waveguide structure includes at least one element having a light emitting part or a light receiving part and a terminal.
(31) The optical waveguide structure according to any one of (1) to (30), wherein the element is bonded to a surface of the optical waveguide body.
(32) The optical waveguide structure according to any one of (1) to (30), wherein at least a part of the element is installed inside the optical waveguide body.
(33) The optical waveguide structure according to any one of (30) to (32), wherein the optical waveguide structure has two or more elements that operate independently of each other, operate in conjunction with each other, or operate synchronously.
(34) The optical waveguide structure according to any one of (1) to (33), which has a conductor layer.
(35) The optical waveguide structure according to any one of (30) to (34), further including a conductor layer, wherein the terminal is electrically connected to the conductor layer.
(36) An electronic device comprising the optical waveguide structure according to any one of (1) to (35).

According to the present invention, the core part is three-dimensionally arranged, and the patterning of the core part can be performed by a simple method of irradiation with active radiation (active energy ray, electron beam, X-ray, etc.). Therefore, a core part having a wide degree of freedom in designing the pattern shape of the core part, that is, the arrangement of the optical path, and high dimensional accuracy is obtained.

In addition, when the core layer is made of a desired material, even if stress is applied to the optical waveguide body or deformation occurs, delamination between the core and cladding and microcracks occur in the core. As a result, the optical transmission performance of the optical waveguide is maintained and the durability is excellent.

Furthermore, when the core part is composed of a resin composition mainly composed of norbornene-based resin, the effect of being particularly strong against the deformation and being difficult to cause defects is high, and the difference in refractive index between the core part and the cladding part is increased. The optical waveguide can be made larger, and has excellent heat resistance, and as a result, an optical waveguide with higher performance and durability can be obtained.

When the optical waveguide structure has an element (light emitting element or light receiving element), the light emitted from the light emitting portion of the element is guided to another place by the optical waveguide by being optically connected to the optical waveguide, or Light from other places can be guided to the light receiving portion of the element by the optical waveguide, and a small and integrated optical circuit can be formed.

In addition, when a conductor layer is formed, wiring to the element is easy, and wiring suitable for the element can be made regardless of the type of element (terminal installation location), and the versatility is high. Moreover, such a wiring circuit pattern using a conductor layer has a wide degree of freedom in design (for example, a degree of freedom in selection of a terminal installation location).

Such an optical waveguide structure of the present invention has a wide range of optical circuit (optical waveguide pattern) and electrical circuit design, good yield, high optical transmission performance, excellent reliability and durability, Rich in versatility. Therefore, the present invention can be used for various electronic components, electronic devices, and the like.

It is a perspective view which shows 1st Embodiment of the optical waveguide structure of this invention. It is a figure which shows arrangement | positioning of the core part of the 1st step | paragraph core layer in the optical waveguide structure shown in FIG. It is a figure which shows arrangement | positioning of the core part of the 2nd step | paragraph core layer in the optical waveguide structure shown in FIG. It is a figure which shows arrangement | positioning of the core part of the 3rd step | paragraph core layer in the optical waveguide structure shown in FIG. It is sectional drawing which shows the example of the layer structure of an optical waveguide main body. It is sectional drawing which shows the example of the layer structure of an optical waveguide main body. It is sectional drawing which shows the example of the layer structure of an optical waveguide main body. It is a perspective view which shows 2nd Embodiment of the optical waveguide structure of this invention. It is sectional drawing which shows typically the example of a process of the manufacturing method of an optical waveguide. It is sectional drawing which shows typically the example of a process of the manufacturing method of an optical waveguide. It is sectional drawing which shows typically the example of a process of the 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 of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is a perspective view showing a first embodiment of the optical waveguide structure of the present invention, and FIG. 2 is an arrangement (pattern) of the core portion of the first core layer in the optical waveguide structure shown in FIG. FIG. 3 is a diagram showing the arrangement (pattern) of the core portion of the second-stage core layer in the optical waveguide structure shown in FIG. 1, and FIG. 4 is the three-stage in the optical waveguide structure shown in FIG. It is a figure which shows arrangement | positioning (pattern) of the core part of the core layer of an eye. Hereinafter, a configuration example of the optical waveguide structure will be described with reference to these drawings.

In the following description, directions of X, Y, and Z (X, Y, and Z are directions orthogonal to each other) shown in FIG. 1 are respectively referred to as “X direction”, “Y direction”, and “Z direction”. In other words, directions opposite to the X direction, Y direction, and Z direction are referred to as “−X direction”, “−Y direction”, and “−Z direction”, respectively. Further, the upper part in FIG. 1 of the optical waveguide structure is referred to as “upper” or “upper stage”, the lower part is referred to as “lower” or “lower stage”, and an intermediate portion between the upper stage and the lower stage is referred to as “middle stage”. In addition, the upper surface of the optical waveguide body in FIG. 1 (FIG. 8) is the “upper surface”, the lower surface is the “lower surface”, the right surface is the “right surface”, the front surface is the “front surface”, and the back surface. The side surface is called the “back”.

<First Embodiment: FIG. 1>
As shown in FIG. 1, the optical waveguide structure 1 of the present invention includes a block-shaped optical waveguide body 2 and five light emitting elements 61, 62, 63, 64 and 65.

The light emitting elements 61, 62, 63, 64 and 65 have light emitting portions 610, 620, 630, 640 and 650 and a pair of terminals (not shown), respectively. For example, when a current is applied (given a potential difference) between the terminals of the light emitting element 61, the light emitting unit 610 is turned on (emits light). The same applies to the other light emitting elements 62-65.

The light emitting units 610 to 650 of the light emitting elements 61 to 65 may each be composed of a single light emitting point, or may be a set of a plurality of light emitting points. As a set of a plurality of light emitting points, for example, the light emitting points are arranged in a row (for example, 1 × 4, 1 × 12) or in a matrix (for example, n × m: n, m And those in which a plurality of light emitting points are arranged randomly (irregularly). The same applies to a light receiving portion in a light receiving element to be described later.

The light emitting elements 61 to 65 are joined to the surface of the optical waveguide body 2 such that the light emitting portions 610 to 650 are in contact with or face the surface of the optical waveguide body 2. However, in the present invention, all or a part of each of the light emitting elements 61 to 65 may be installed (embedded) inside the optical waveguide body 2. The same applies to the case where a light receiving element is installed together with the light emitting elements 61 to 65 or instead of the light emitting elements 61 to 65.

Each of the light emitting elements 61 to 65 operates (emits light) independently, but any two or more of them emit light in conjunction (particularly simultaneously) or emit light synchronously. You may do it. The light emission pattern of each of the light emitting elements 61 to 65 can be arbitrarily set, and the light emission pattern may change with time.

The optical waveguide body 2 is formed by laminating a clad layer 91 and a core layer 93 in a predetermined order. In this case, the optical waveguide body 2 includes a plurality of cladding layers 91 and a plurality of core layers 93 (three steps in the Z direction).

Each core layer 93 is formed with a core portion 94 and a clad portion 95 having a predetermined pattern (see FIGS. 1 to 4). The core portion 94 is a portion that forms an optical path of the transmission light, and the cladding portion 95 is a portion that is formed in the core layer 93 but does not form an optical path of the transmission light and performs the same function as the cladding layer 91. is there.

The core portion 94 has a higher refractive index than the clad portion 95, and also has a higher refractive index than the clad layer 91. The clad portion 95 exists on both sides of the core portion 94, and the clad portion 95 or the clad layer 91 exists below and above the core portion 94. With such a configuration, the core portion 94 functions as a light guide path (optical waveguide) surrounded by the clad portion on the entire outer periphery.

As shown in FIG. 1, the core portion 94 is three-dimensionally arranged in the optical waveguide body 2. That is, the core portion 4 preferably has a portion extending in at least one of the X (-X), Y (-Y) and Z (-Z) directions, and X (-X ), Y (-Y), and Z (-Z) directions, and more preferably has a portion extending in at least two directions.

The clad layer 91 transmits the transmitted light with a relatively high transmittance when the transmitted light is incident on the clad layer 91 in a layer thickness direction (a direction perpendicular to the clad layer).

As a constituent material of the core layer 93, a material whose refractive index is changed by irradiation with active radiation (active energy ray, electron beam, X-ray or the like) or further heating is used. Preferable examples of such materials include those mainly composed of a resin composition containing a cyclic olefin resin such as a benzocyclobutene resin polymer and a norbornene polymer (resin), including a norbornene polymer ( The main 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 layer 91 or the other core layer 93) 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 is maintained, and an optical waveguide excellent in durability can be 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 types) is preferably about 0.5 to 40% by weight, preferably 3 to 30% by weight, based on the entire constituent material of the core layer 93. The degree is more preferred. 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 actinic radiation using a mask to pattern the core portion 94 having a desired shape.

Examples of active radiation used for exposure include active energy rays such as visible light, ultraviolet light, infrared light, and laser light, electron beams, and X-rays. The electron beam can be irradiated at an irradiation dose of, for example, about 50 to 2000 KGy.

In the core layer 93, the refractive index of the portion irradiated with the active radiation changes (the refractive index may increase or decrease depending on the material of the core layer 93), and the active radiation is not irradiated. A difference in refractive index occurs between the parts. For example, a portion of the core layer 93 that has been irradiated with active radiation becomes the cladding portion 95, and a portion that has not been irradiated becomes the core portion 94. The reverse is also true. The refractive index of the cladding part 95 is substantially equal to the refractive index of the cladding layer 91.

Further, the core portion 94 may be formed by irradiating the core layer 93 with active radiation in a predetermined pattern and then heating the core layer 93. 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.

The pattern shape of the core portion 94 to be formed is not particularly limited, and is a straight shape, a shape having a curved portion, an irregular shape, a shape having a branching portion of a light path, a merging portion or a crossing portion, a condensing portion (a width etc. is reduced). Or a light diffusing part (a part where the width or the like is increased), or a combination of two or more of these. The feature of the present invention is that the core portion 94 having any shape can be easily formed by setting the irradiation pattern of the active radiation.

Hereinafter, the arrangement (pattern) of the core portion 94 in each core layer in the optical waveguide body 2 will be specifically described.

<First (upper) core layer>
As shown in FIG. 2, three core portions 94 having a longitudinal shape extending in the Y direction are spaced apart from each other in the X direction by a core layer 93 in the first stage (upper stage) from the top in the optical waveguide body 2. And formed (arranged) substantially in parallel.

2, one end of the core portion 94 in the left column is exposed on the back surface of the optical waveguide body 2, and the exposed surface constitutes an output end 942 of the transmission light 711. An optical path conversion unit (light emitting unit side optical path conversion unit) 4 a that bends the optical path of the core unit 94 is provided at the end of the core unit 94 opposite to the emission end 942.

The optical path conversion unit 4a is composed of a reflecting surface (mirror) 5a that reflects at least a part of the transmitted light. The same applies to reflecting surfaces 5b, 5c, 5d and 5e described later.

The reflecting surface 5a is inclined by approximately 45 ° with respect to the longitudinal direction of the core portion 94, reflects a part of the transmitted light 71 (for example, 50% of the light amount), and transmits the remaining part of the beam splitter (half mirror or dichroic mirror). The transmission light 71 emitted from the light emitting unit 610 is divided into a plurality of directions (two directions orthogonal to each other). Then, by setting the reflectance (transmittance) of the reflecting surface 5a, the light amounts of the divided transmission lights 711 and 712 can be set to a predetermined ratio. As a typical example, the light amounts of the transmission lights 711 and 712 can be made substantially equal.

The optical path conversion unit 4a can, for example, form an inclined surface by obliquely cutting (removing) a part (end portion) of the core portion 94 and using the inclined surface as the reflecting surface 5a. The reflecting surface 5a may have a reflecting film or a reflection increasing film such as a multilayer optical thin film or a metal thin film (for example, an aluminum vapor deposition film). Although not shown, the inclined surface of the optical path changing portion 4a may be filled or joined with a filler, particularly a filler having a refractive index different from that of the core portion 94. The same applies to reflective surfaces 5b, 5c, 5d and 5e described later.

The core portions 94 in the right column in FIG. 2 are continuously formed from the back surface to the front surface of the optical waveguide body 2, and the light emitting element 640 faces the exposed surface of the core portion 94 on the back surface. 64, and the exposed surface of the core portion 94 to the front surface constitutes an output end 943 of the transmission light 741. Moreover, the core part 94 of the right row in FIG. 2 branches in the branch part 941 in the middle, and forms the core part 94 of the center row | line | column in FIG. The core portion 94 is exposed on the front surface of the optical waveguide body 2, and the exposed surface constitutes an output end 944 of the transmission light 742.

In the branching section 941, the transmission light 74 emitted from the light emitting section 640 is separated into transmission lights 741 and 742. The ratio of the light amounts of the transmission light 741 and the transmission light 742 is not particularly limited, and can be, for example, about 1: 9 to 9: 1. Instead of the branching portion 941, a reflection surface (beam splitter: half mirror or dichroic mirror) similar to the reflection surface 5a may be provided to branch (divide) the optical path in a plurality of directions.

Moreover, you may have the confluence | merging part of the structure similar to the branch part 941. FIG. In this case, in the illustrated branching portion 941, the direction of the transmitted light is opposite, and the two core portions (optical paths) are merged into one core portion (optical path).

<Second (middle) core layer>
As shown in FIG. 3, one long core portion 94 extending in the X direction is formed (arranged) on the second (middle) core layer 93 from the top in the optical waveguide body 2. One end of the core portion 94 is exposed on the right side surface of the optical waveguide body 2, and the exposed surface constitutes an output end 945 of the transmission light 72. An optical path conversion section (light emitting section side optical path conversion section) 4b that bends the optical path of the core section 94 is provided at the end of the core section 94 opposite to the emission end 945.

The optical path changing unit 4b is composed of a reflecting surface (mirror) 5b that reflects at least a part of the transmitted light. The reflecting surface 5b is inclined by approximately 45 ° with respect to the longitudinal direction of the core portion 94, and constitutes a total reflection mirror that reflects almost all of the transmitted light 72 (for example, 90% or more of the light amount).

<Third (lower) core layer>
As shown in FIG. 4, in the core layer 93 at the third level (lower level) from the top in the optical waveguide body 2, three longitudinal core portions 94 extending in the Y direction have a predetermined interval in the X direction. And formed (arranged) substantially in parallel.

4, one end of the core portion 94 in the left column is exposed on the back surface of the optical waveguide body 2, and the exposed surface constitutes the output end 946 of the transmission light 712. An optical path conversion section (light emitting section side optical path conversion section) 4 c that bends the optical path of the core section 94 is provided at the end of the core section 94 opposite to the emission end 946.

The optical path changing unit 4c is composed of a reflecting surface (mirror) 5c that reflects at least a part of the transmitted light. The reflection surface 5c is inclined by approximately 45 ° with respect to the longitudinal direction of the core portion 94, and reflects the entire transmission light 712 (for example, 90% or more of the amount of light) transmitted through the reflection surface 5a located above. Is configured.

4, one end of the core portion 94 in the center row is exposed on the front surface of the optical waveguide body 2, and the exposed surface constitutes an output end 947 of the transmission light 73. An optical path conversion unit (light emitting unit side optical path conversion unit) 4d that bends the optical path of the core unit 94 is provided at the end of the core unit 94 opposite to the emission end 947.

The optical path changing unit 4d is composed of a reflecting surface (mirror) 5d that reflects at least a part of the transmitted light. The reflecting surface 5d is inclined by approximately 45 ° with respect to the longitudinal direction of the core portion 94, and constitutes a total reflection mirror that reflects almost all of the transmitted light 73 (for example, 90% or more of the light amount).

4, one end of the core portion 94 in the right column is exposed on the front surface of the optical waveguide body 2, and the exposed surface constitutes the emission end 948 of the transmission light 75. The core portion 94 is bent in an L shape in the X direction in the middle, and an end portion thereof (an end portion opposite to the emission end 948) is exposed on the right side surface of the optical waveguide body 2. On the exposed surface, the light emitting element 65 is installed so that the light emitting unit 650 faces. The bent portion of the core portion 94 is provided with an optical path changing portion (light emitting portion side optical path changing portion) 4e for bending the optical path of the core portion 94.

The optical path conversion unit 4e is composed of a reflective surface (mirror) 5e that reflects at least a part of the transmitted light. The reflection surface 5e is inclined by approximately 45 ° with respect to the longitudinal direction of the core portion 94, and constitutes a total reflection mirror that reflects almost all of the transmitted light 75 (for example, 90% or more of the light amount).

As shown in FIG. 1, light emitting elements 61, 62, and 63 are installed at predetermined positions on the upper surface of the optical waveguide body 2 so that the light emitting portions 610, 620, and 630 face each other.

The light emitting element 61 is installed at a position where the reflecting surface 5a of the optical path changing unit 4a is located directly below the light emitting unit 610. Further, the reflection surface 5c of the optical path conversion unit 4c is located directly below the reflection surface 5a. In other words, when viewed in the Z direction, the light emitting unit 610, the reflective surface 5a, and the reflective surface 5c coincide.

Further, the light emitting element 62 is installed at a position where the reflecting surface 5b of the optical path changing unit 4b is located directly below the light emitting unit 620. That is, when viewed in the Z direction, the light emitting unit 620 and the reflecting surface 5b coincide. In this case, the core portion 94 (see FIG. 2) of the first-stage core layer 93 does not exist immediately below the light emitting portion 620. That is, the transmission light 72 emitted from the light emitting unit 620 does not intersect the core part 94 of the first-stage core layer 93 (transmits through the clad part 95 of the first-stage core layer 93) and is a reflective surface. 5b is reached so that crosstalk is prevented.

Further, the light emitting element 63 is installed at a position where the reflecting surface 5d of the optical path changing unit 4d is located directly below the light emitting unit 630. That is, when viewed in the Z direction, the light emitting unit 630 and the reflecting surface 5d are coincident with each other. In this case, the core portion 94 (see FIG. 2) of the first-stage core layer 93 and the core portion 94 (see FIG. 3) of the second-stage core layer 93 are not present immediately below the light emitting portion 630. That is, the transmission light 73 emitted from the light emitting unit 630 does not intersect the core part 94 of the first-stage core layer 93 (transmits through the cladding part 95 of the first-stage core layer 93), and further 2 It does not intersect with the core portion 94 of the core layer 93 at the stage (transmits through the clad portion 95 of the core layer 93 at the second stage) and reaches the reflection surface 5d. Is prevented.

Further, the light emitting element 65 is installed at a position where the light emitting unit 650 and the reflecting surface 5e of the optical path changing unit 4e coincide when viewed in the X direction.

Although not shown, a light receiving element may be installed in a part or all of the emission ends 942, 943, 944, 945, 946, 947, and 948. The light receiving element includes a light receiving unit and a terminal that photoelectrically converts light received by the light receiving unit and outputs an electrical signal. When the transmission light emitted from the emission ends 942 to 948 is received by the light receiving portion of the light receiving element, an electronic signal is output from the terminal of the light receiving element.

Next, configuration examples of the core layer and the clad layer constituting the optical waveguide body 2 will be described with reference to FIGS.

In the configuration shown in FIG. 5, the clad layers 91 and the core layers 93 are alternately stacked. Each core layer 93 includes a core portion 94 and a clad portion 95 having a predetermined pattern.

In the configuration shown in FIG. 6, a laminate having a three-layer structure in which the clad layers 91 are bonded to both surfaces of one core layer 93 (in other words, the core layer 93 is interposed between the two clad layers 91). (Optical waveguide) 90 is one unit, and two or more of the laminates 90 are stacked. The core layer 93 in each stacked body 90 includes a core portion 94 and a clad portion 95 having a predetermined pattern.

7 includes a core layer stacking portion 92 in which a plurality of core layers 93 are stacked (in the illustrated case, four layers are stacked). Cladding layers 91 are bonded to the upper surface and the lower surface of the core layer stack portion 92, respectively.

Each core layer 93 constituting the core layer laminated portion 92 includes a core portion 94 and a clad portion 95 having a predetermined pattern. In this case, the core layer 93 located at the uppermost part in FIG. 7 and the core layer 93 located at the lowermost part are respectively provided with optical path changing parts 4f and 4g composed of reflecting surfaces 5f and 5g. The two core layers 93 are provided with core portions 94 respectively. Thereby, the transmission light 76 transmitted in the Y direction through the core portion 94 of the core layer 93 positioned at the top in FIG. 7 is reflected by the reflecting surface 5f and bent at a right angle downward (Z direction). The core portion 94 formed in the two core layers 93 in the middle proceeds in the Z direction, is reflected by the reflecting surface 5g and bent at a right angle again, and the core portion 94 of the core layer 93 located at the bottom in FIG. Proceed in the Y direction.

The optical waveguide body 2 in the present invention has at least one of the configurations shown in FIGS. Further, two or more or all of the configurations shown in FIGS. 5 to 7 may be included.

The constituent materials for the core layer 93 and the clad layer 91, the method for forming the core portion 94, and the like will be described in detail later.

The optical waveguide structure 1 of the present invention preferably has a conductor layer (not shown) on the surface and / or inside of the optical waveguide body 2. The conductor layer is preferably patterned into a predetermined shape to form a desired wiring (circuit). Such a conductor layer is preferably electrically connected to the terminals of the light emitting elements 61 to 65 and constitutes a current-carrying wiring to the light emitting elements 61 to 65. In the case where the light receiving element is installed, the conductor layer is preferably electrically connected to a terminal (output terminal) of the light receiving element and used as a circuit for detecting an output signal from the terminal.

Such a conductor layer can also be arranged three-dimensionally on the surface and / or inside of the optical waveguide body 2. That is, the wiring in the conductor layer can be installed so as to extend in two or three directions of the X, Y, and Z directions, for example.

Examples of the constituent material of the conductor layer include various metal materials such as copper, copper-based alloy, aluminum, and aluminum-based alloy. The thickness of the conductor layer is not particularly limited, but is usually preferably about 3 to 120 μm, more preferably about 5 to 70 μm.
Moreover, it is preferable that a conductor layer is formed by methods, such as joining (adhesion) of metal foil, metal plating, vapor deposition, sputtering, etc., for example. For example, etching, printing, masking, or the like can be used for patterning the conductor layer.

Next, the operation of the optical waveguide structure 1 shown in FIGS. 1 to 4 will be described. When the terminal of the light emitting element 61 is energized, the light emitting portion 610 is turned on, and the transmitted light 71 emitted in the Z direction is transmitted through the cladding portion (cladding layer 91 and cladding portion 95) and reflected on the reflecting surface 5a. It is separated into reflected light and transmitted light (see FIG. 1). The transmitted light (reflected light) 711 reflected by the reflecting surface 5a and bent by approximately 90 ° enters the core portion 94 of the first-stage core layer 93, proceeds in the −Y direction, and reaches the emission end 942 (FIG. 2). reference). The transmitted light (transmitted light) 712 that has passed through the reflecting surface 5 a and traveled in the Z direction is reflected (substantially totally reflected) by the reflecting surface 5 c and bent by approximately 90 °, and the core portion 94 of the third-stage core layer 93. Enter the -Y direction and reach the exit end 946 (see FIG. 4).

When the terminal of the light emitting element 62 is energized, the light emitting portion 620 is turned on, and the transmitted light 72 emitted in the Z direction is transmitted through the cladding portion (the cladding layer 91 and the cladding portion 95) and reflected by the reflecting surface 5b. The light is reflected (substantially total reflection) and bent by approximately 90 °, enters the core portion 94 of the second-stage core layer 93, proceeds in the X direction, and reaches the emission end 945 (see FIGS. 1 and 3).

When the terminal of the light emitting element 63 is energized, the light emitting portion 630 is turned on, and the transmitted light 73 emitted in the Z direction is transmitted through the clad portion (the clad layer 91 and the clad portion 95) and reflected by the reflecting surface 5d. The light is reflected (substantially total reflection) and bent by approximately 90 °, enters the core portion 94 of the third-stage core layer 93, proceeds in the Y direction, and reaches the emission end 947 (see FIGS. 1 and 4).

When the terminal of the light emitting element 64 is energized, the light emitting portion 640 is turned on, and the transmitted light 74 emitted in the Y direction enters the core portion 94 of the first core layer 93 and proceeds in the Y direction to branch. In the section 941, the transmission light 741 and the transmission light 742 are separated. The transmitted light 741 and 742 respectively travel in the core portion 94 on the Y direction side from the branch portion 941 and reach the emission ends 943 and 944 (see FIGS. 1 and 2).

When the terminal of the light emitting element 65 is energized, the light emitting portion 650 is turned on, and the transmitted light 75 emitted toward the −X direction enters the core portion 94 of the third core layer 93 and proceeds in the −X direction. Then, it is reflected by the reflecting surface 5e (substantially totally reflected) and bent by approximately 90 °, proceeds in the Y direction, and reaches the emission end 948 (see FIGS. 1 and 4).

FIG. 8 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.

The optical waveguide structure 1 of the present embodiment has an inclined surface 3 in which at least one surface of the optical waveguide body 2 is inclined. That is, as shown in FIG. 8, the front surface of the optical waveguide body 2 is a cross section (= XZ plane) of the core portion (core portion extending in the Y direction) 94 of the first and third core layers 93. In contrast, the inclined surface 3 is inclined at an angle of approximately 45 ° (θ = 45 °). As a result, the exposed surfaces (exposed end surfaces) 961, 962, 963, 964, and 965 of the core portion 94 exposed on the inclined surface 3 are also inclined surfaces having the same angle. These exposed surfaces 961, 962, 963, 964, and 965 can be used as reflecting surfaces (total reflection surfaces: reflectance of 90% or more). For example, a reflective film such as a multilayer optical thin film or a metal thin film (for example, an aluminum vapor deposition film) or a reflection increasing film can be provided on these exposed surfaces 961 to 965 as described above.

With this configuration, the exposed surface 961 reflects the transmitted light 71 in the Z direction emitted from the light emitting unit 610 of the light emitting element 61 so as to bend in the −Y direction, thereby exposing the exposed surfaces 962, 963, and 964. And 965 respectively reflect the transmitted lights 742, 741, 73, and 75 traveling in the core portion 94 so as to bend in the −Z direction.

In the present embodiment, since the exposed surface 961 is a reflection surface that substantially totally reflects, the left row of core portions 94 (corresponding to the left row of core portions 94 in FIG. 4) of the third-stage core layer 93 and the optical path. There is no conversion unit 4c.

Note that the inclination angle θ (angle formed with the XZ plane) θ of the inclined surface 3 is not limited to 45 °, and for example, θ can be about 20 to 70 °. Further, the exposed surfaces 961 to 965 are not limited to the total reflection surface, but may be ones having a function of separating transmitted light into reflected light and transmitted light (beam splitter) such as a half mirror or a dichroic mirror. .

Further, it goes without saying that the inclined surface 3 is not limited to the one formed for the purpose of bending the optical path by reflection or the like. Such an inclined surface may be formed on a surface other than the front surface of the optical waveguide body 2, or may be formed on two or more surfaces of the optical waveguide body 2.

As mentioned above, although each 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 any two or more of the embodiments described above.

In the optical waveguide structure of the present invention as described above, by performing a bending operation, the substrate 2 and the optical waveguide 9 are bent (bent), the bending operation is released, and the substrate 2 and the optical waveguide 9 are extended. It is possible to freely take the stretched state. For this reason, for example, it can be suitably used for hinges and slides of electronic devices such as mobile phones, game machines, PDAs, and notebook personal computers having hinges or slides. For example, in a mobile phone, when two points via a hinge part are connected by an optical waveguide structure, when the hinge part of the mobile phone is closed, the optical waveguide structure is bent and when the hinge part is opened, The optical waveguide structure is in an extended state.

In this way, the optical waveguide structure can maintain the electrical connection and the optical connection between two points sandwiching the movable part over a long period of time. For this reason, the mobile phone (electronic device) provided with the optical waveguide structure can improve the reliability.
Note that the electronic device to which the optical waveguide structure of the present invention is applied is not limited to the above-described ones. For example, it is suitable for application to electronic devices such as router devices, WDM devices, personal computers, televisions, home servers, and the like. is there. 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, by providing such an electronic device with the opto-electric hybrid board according to the present invention, problems such as noise and signal deterioration peculiar to the electric wiring are eliminated, and a dramatic improvement in the 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.

Next, the manufacturing method of the optical waveguide main body (optical waveguide) 2 and the constituent materials of each part in each of the above embodiments will be described. In particular, the method of 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.

In the present embodiment, the photosensitive resin composition used for forming the core portion 94 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 preferably contains a monomer of the above 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.

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) addition copolymers of norbornene monomers with ethylene and 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).

Of these, addition (co) polymers are preferred as the norbornene-based resin. 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 norbornene repeating units containing such a polymeric group is used, both flexibility and heat resistance can be achieved.
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).

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

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.

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.

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.

(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.

As the norbornene-based polymer represented by the formula (4), for example, any one of butyl norbornene, hexyl norbornene or decyl norbornene, 2- (5-norbornenyl) methyl acrylate, norbornenyl ethyl trimethoxysilane, Terpolymer with either triethoxysilyl norbornene or trimethoxysilyl norbornene, butyl bornene, hexyl norbornene or decyl norbornene, terpolymer of 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 norbornene or trimethoxysilyl norbornene.

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.

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 in which 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.

Further, 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 to 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, 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.
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 are cases where the Si—O—X ₃ portion of the alkoxysilyl group is eliminated.

For example, when the norbornene-based resin of the 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.

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 group of 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.

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 the compound represented by the formula (32), trade name TOSOX manufactured by Toagosei Co., Ltd., and as the compound represented by formula (33), trade name OX-SQ manufactured by Toagosei Co., Ltd. can be used.

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. Among them, it is preferable to use an alicyclic epoxy monomer represented by the formulas (36) to (39) from the viewpoint that the strain energy of the epoxy ring is large and the reactivity is excellent.
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. As this compound, for example, E0327 manufactured by Tokyo Chemical Industry can be used.
Further, 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. The compound represented by the formula (38) is 1,2-epoxy-4-vinylcyclohexane, and 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 have 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 actinic radiation, a light irradiated part and an unirradiated part The refractive index difference 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 can generate Bronsted acid or Lewis acid by absorbing light (active radiation) energy. For example, triphenylsulfonium trifluoromethanesulfonate, tris (4-t-butyl) can be used. Sulfonium salts such as phenyl) sulfonium-trifluoromethanesulfonate, diazonium salts such as p-nitrophenyldiazonium hexafluorophosphate, ammonium salts, phosphonium salts, diphenyliodonium trifluoromethanesulfonate, (triccumyl) iodonium-tetrakis (pentafluorophenyl) borate, etc. Iazonium salts, quinonediazides, diazomethanes such as bis (phenylsulfonyl) diazomethane, 1-phenyl-1- (4-methylpheny ) Sulfonic acid esters such as sulfonyloxy-1-benzoylmethane, N-hydroxynaphthalimide-trifluoromethanesulfonate, disulfones such as diphenyldisulfone, tris (2,4,6-trichloromethyl) -s-triazine, 2 Mention may be made of 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 and an antioxidant in addition to the components (A), (B), and (C).
The sensitizer increases the sensitivity of the photoacid generator to actinic radiation, reduces the time and energy required to activate (react or decompose) the photoacid generator, and activates the photoacid generator. It has a function of changing the wavelength of actinic radiation to a suitable 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.

Furthermore, an antioxidant can be added to the core layer forming material 900. Thereby, generation | occurrence | production of an undesirable free radical and the natural oxidation of the polymer 915 can be prevented. As a result, the characteristics of the obtained core layer 93 (optical waveguide 9) can be improved.

Examples of the antioxidant include Ciba (registered trademark, the same applies hereinafter) IRGANOX (registered trademark, the same applies hereinafter) 1076 and Ciba IRGAFOS (registered trademark, available) from Ciba Specialty Chemicals of Tarrytown, New York. The same applies hereinafter.) 168 is preferably used.

Other antioxidants include, for example, Ciba Irganox (registered trademark, hereinafter the same) 129, Ciba Irganox 1330, Ciba Irganox 1010, Ciba Cyanox (registered trademark, the same applies below) 1790, CibaI. (Registered trademark) 3114, Ciba Irganox 3125, etc. can also be used.

It should be noted that such an antioxidant can be omitted, for example, when the film 910 is not exposed to oxidation conditions or when the period of time is very short.

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 above 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, a polymer of a monocyclic monomer such as cyclohexene or 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 copolymerizable monomers 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. 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 above-described —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 above formula (101) and / or the above formula (102) is preferable. Thereby, the refractive index of resin can be made high.

The photosensitive resin composition contains 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 the photosensitive resin composition as described above is used, it is excellent in the refractive index modulation between the core and the clad when the first monomer starts a polymerization reaction due to an acid generated by actinic radiation irradiation or the like. This is because the first monomer is excellent in 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 active radiation irradiated region and the unirradiated 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, particularly preferably 0 by weight ratio (weight of the second monomer / weight of the first monomer). .1 to 0.6 is preferable. 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.

(Optical waveguide manufacturing method)
9, 10, and 11 are cross-sectional views schematically showing process examples of the 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. 9A, 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 a varnish form 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), N, N-dimethylacetamide (DMA), halogen compound solvents such as dichloromethane, chloroform, 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. As a result, as shown in FIG. 9B, 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 irradiation with actinic radiation 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 active radiation (for example, ultraviolet rays).
At this time, as shown in FIG. 10A, a mask M in which an opening is formed is disposed above the film 910. The film 910 is irradiated with active radiation through the opening of the mask M.
Examples of the actinic radiation used include those having a peak wavelength in the wavelength range of 200 to 450 nm. Thereby, although depending on the composition of the photoacid generator, the photoacid generator can be activated relatively easily.

The constituent material of the mask M is appropriately selected depending on the active radiation to be irradiated. Specifically, the constituent material of the mask M is a material that can block the active radiation applied to the film 910. Any known material can be used for the mask M as long as it has such characteristics.

The mask M may be formed in advance (separately formed) (for example, plate-shaped) or may be formed on the film 910 by, for example, a vapor deposition method or a coating method.

Preferred examples of the mask M include photomasks made of quartz glass and PET base materials, stencil masks, metal thin films formed by vapor deposition methods (evaporation, sputtering, etc.), etc. Among these, it is particularly preferable to use a photomask or a stencil mask. This is because a fine pattern can be formed with high accuracy, and handling is easy, which is advantageous in improving productivity.

The irradiation amount of the active radiation is not particularly limited, but is preferably about 0.1 to 9 J / cm ² , more preferably about 0.2 to 6 J / cm ² , and 0.2 to 3 J More preferably, it is about / cm ² .
In addition, when using active radiation with high directivity like a laser beam, use of the mask M can also be abbreviate | omitted.

In the region of the film 910 that has been irradiated with actinic radiation, an acid is generated from the photoacid generator. The component (B) is polymerized by the generated acid.
In the region not irradiated with actinic radiation, 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 difference in refractive index 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 above-described photosensitive resin composition is used, the polymerization of the component (B) can be initiated by the acid generated from the photoacid 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 actinic radiation, 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, —Si-diphenyl structure, and —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 actinic radiation 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. 10B, the region irradiated with actinic radiation becomes the clad portion 95 and the unirradiated 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., more preferably about 40 to 160 ° C.
The heating time is preferably set so that the polymerization reaction of the component (B) in the irradiated part irradiated with actinic radiation is almost completed, and specifically, it is 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 96. The pair of clad layers 91 and 96 are arranged so as to sandwich the core portion 94 from a direction different from the clad portion 95.
The clad layer 94 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.
Further, when an optical waveguide structure having a core layer laminated portion as shown in FIG. 7 is manufactured, a core layer 93 is further laminated instead of the cladding layer 96. The core layer 93 may be laminated by repeating the method for forming the core layer 93 as described above, or a desired number of film-like core layers produced on another base material may be laminated. . Moreover, you may combine these methods.

As a method for forming the clad layer 91 (96), a varnish containing a clad material (clad layer forming material) is applied and cured (solidified), or a curable monomer composition is applied and cured (solidified). Any method may be used.

When the clad layer 91 (96) is formed by a coating method, examples thereof include 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.

Examples of the constituent material of the cladding layer 91 (96) include cyclic olefins such as acrylic resin, methacrylic resin, polycarbonate, polystyrene, epoxy resin, polyamide, polyimide, polybenzoxazole, benzocyclobutene resin, and norbornene resin. These resins can be used, and one or more of these can be used in combination (polymer alloy, polymer blend (mixture), copolymer, composite (laminate), etc.).

Of these, epoxy resins, polyimides, polybenzoxazoles, cyclic olefin resins such as benzocyclobutene resins and norbornene resins, and those containing them (mainly) in terms of particularly excellent heat resistance It is preferable to use, and particularly, those mainly composed of norbornene-based resins (norbornene-based polymers) are preferable.

Since the norbornene-based polymer is excellent in heat resistance, in the optical waveguide 9 using this as a constituent material of the cladding layer 91 (96), when the conductor layer is formed on the optical waveguide 9, the conductor layer is processed to form a wiring. In this case, even when the optical element is heated to mount it, the clad layer 91 (96) can be softened and prevented from being deformed.

Further, since it has high hydrophobicity, it is possible to obtain the clad layer 91 (96) which is less likely to cause dimensional change due to water absorption.

Further, norbornene-based polymers or norbornene-based monomers that are raw materials thereof are preferable because they are relatively inexpensive and easily available.

Further, when a material mainly composed of a norbornene-based polymer is used as the material of the clad layer 91 (96), the clad layers 91 and 96 and the core layer 93 are excellent in resistance to deformation such as bending, even when repeatedly bent and deformed. The delamination is difficult to occur, and the occurrence of microcracks in the clad layers 91 and 96 is also prevented. In addition, since it is the same type of material that is suitably used as the constituent material of the core layer 93, the adhesion to the core layer 93 is further increased, and delamination between the cladding layer 91 (96) and the core layer 93 is achieved. Can be prevented. For this reason, the optical transmission performance of the optical waveguide 9 is maintained, and the optical waveguide 9 having excellent durability can be obtained.

The average thickness of the cladding layers 91 and 96 is preferably about 0.1 to 1.5 times the average thickness of the core layer 93, more preferably about 0.3 to 1.25 times. Specifically, the average thickness of the clad layers 91 and 96 is not particularly limited, but each of them is usually preferably about 1 to 200 μm, more preferably about 5 to 100 μm, and about 10 to 60 μm. More preferably. Thereby, the function as a clad layer is suitably exhibited while preventing the optical waveguide 9 from becoming unnecessarily large (pressure film).

Through the above steps, the optical waveguide 9 shown in FIG. 11 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 96, and then the clad layer 91 and the clad layer 96 may be overlapped via the core layer 93. .
Examples of the substrate include a silicon substrate, a silicon dioxide substrate, a glass substrate, a quartz substrate, and a polyethylene terephthalate (PET) film.

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 irradiation with actinic radiation, the component (B) is volatilized 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 active radiation. 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, which has been conventionally used, is selectively irradiated with actinic radiation to generate an 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 difference can be made.
On the other hand, when the photosensitive resin composition used in this embodiment is selectively irradiated with actinic radiation, the amount of the component (B) in the irradiated portion is reduced due to the generation of acid, so the component (B ) Diffuses to the irradiated part, and as a result, a difference in refractive index occurs between the irradiated part and the unirradiated part.

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 actinic radiation 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 that the core portion and the cladding portion are refracted depending on conditions such as irradiation with actinic radiation and heating. It can suppress that a rate fluctuates.

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 monomers, the monomer can form a reactant upon irradiation with actinic radiation, and the refractive index of a region irradiated with actinic radiation can be made different from that of an 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 irradiation with actinic radiation. Due to the change in the activation temperature, the temperature at which the monomer reaction is started is different between the irradiated region and the non-irradiated region, and as a result, a reactant can be formed only in the irradiated region.

On the other hand, the photosensitive resin composition used in this embodiment does not require a substance containing such a large amount of metal elements. For this reason, the increase of the propagation loss as described above is prevented, and the optical waveguide 9 excellent in propagation efficiency and heat resistance can be obtained.
Even when such a conventional composition is used, the core part and the clad part can be separately formed by irradiation with actinic radiation. However, according to the photosensitive resin composition used in the present embodiment, the core part 94 and the clad part are formed. Since the difference in refractive index with the portion 95 is further expanded and the heat resistance is improved, the optical waveguide 9 with higher reliability can be obtained. This is mainly due to the optimization of the composition of component (A) and component (B).

By using such a photosensitive resin composition, the present invention can provide an optical waveguide film or the like in which generation of light propagation loss is suppressed. In particular, when a curved optical waveguide is formed, generation of light propagation loss can be remarkably suppressed.

When the structure shown in FIG. 7 is manufactured, a plurality of core layers 93 are produced by the above-described method, and the core layer laminated portion 92 is obtained by overlapping (bonding) these layers. In this case, the pattern of the core portion 94 in each core layer 93 can form a predesigned three-dimensional optical path pattern when the core layers 93 are laminated in a desired order.

Further, the configuration shown in FIG. 7 is completed by bonding (crimping) the above-described cladding layer 91 to the upper surface and the lower surface of the core layer laminated portion 92, respectively. As another method, a plurality of core layers 93 may be sequentially laminated (bonded) to the lower clad layer 91 in FIG. 6, and finally the upper clad layer 91 in FIG. 6 may be bonded (crimped).

6 is manufactured, a plurality of optical waveguides (laminated body 90) are prepared by the above-described method, and these are overlapped and bonded (crimped). In this case, the pattern of the core portion 94 in the core layer 93 of each stacked body 90 can form a pre-designed three-dimensional optical path pattern when the stacked bodies 90 are stacked in a desired order. .

Further, when manufacturing the configuration shown in FIG. 5, for example, the following three methods are possible. First, as a first method, there is a method in which one optical waveguide (laminated body 90) is produced, a core layer 93 and a clad layer 91 are repeatedly laminated in this order, and these are pressure-bonded. As a second method, there is a method in which two optical waveguides (laminated body 90) are produced, a core layer 93 is interposed between the optical waveguides (laminated body 90), and these are crimped and integrated. As a third method, there is a method in which a plurality of two-layer laminates in which the clad layer 91 and the core layer 93 are laminated are produced, and the respective two-layer laminates are laminated in a desired order, followed by pressure bonding. As a fourth method, there is a method in which each of the clad layer 91 and the core layer 93 is produced one by one, these are laminated in a desired order, and pressure-bonded.

In the manufacturing method of the optical waveguide body (optical waveguide) 2 as described above, the pattern of the core portion 94 in each core layer 93 is designed in advance when the clad layers 91 and the core layers 91 are laminated in a desired order. An optical path pattern in a three-dimensional direction can be formed.

Further, according to the manufacturing method as described above, an optical waveguide having a core portion 94 having a desired shape and high dimensional accuracy can be obtained with a simple process and in a short time.

In the present invention, it goes without saying that the basic structure, layer structure, shape, number, arrangement, etc. of the optical waveguide structure are not limited to those shown in the drawings.

In each of the above embodiments, the configuration including the light emitting elements 61 to 65 as the element has been described. However, the configuration may include one or more light receiving elements, or one or more light emitting elements and one or more. The light receiving element may be provided. Of course, the structure which has two or more sets of a light emitting element and a light receiving element may be sufficient.

The present invention has been described based on the illustrated embodiments. However, the present invention is not limited to these embodiments, and the configuration of each part can be replaced with any configuration that can exhibit the same function. In addition, an arbitrary configuration may be added.

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 according to 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 according to identification by NMR. The refractive index by Metricon was 1.55 (measurement wavelength: 633 nm).

(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) 1st 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 difference in refractive index between the left and right core portions and the clad portion formed in the above (formation of the core layer) in the horizontal direction was determined as follows.
Optical waveguide analyzer OWA-9500 manufactured by EXFO of 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 washing process three times in total, the oil layer was dropped into a large excess of acetone to reprecipitate the polymer produced, and the polymer was 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 according to 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 according to identification by NMR. The refractive index by Metricon was 1.54 (measurement wavelength: 633 nm).

(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 Toagosei Co., Ltd. CHOX, CAS # 483303-25-9, 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), Toa Gosei, 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, 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 and 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 Toa Gosei Co., Ltd. 1 g of alicyclic epoxy monomer (manufactured by Daicel Chemical Industries, Celoxide 2021P), 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 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 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, and a stirrer chip is put in, tightly plugged, 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 washing process three times in total, the oil layer was dropped into a large excess of acetone to reprecipitate the polymer produced, and the polymer was 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 according to GPC measurement. According to the identification by NMR, the molar ratio of each structural unit in polymer # 3 is 40 mol% for hexylbornene structural unit, 30 mol% for diphenylmethylnorbornenemethoxysilane structural unit, and 30 mol% for epoxynorbornene structural unit. there were. The refractive index by Metricon was 1.53 (measurement wavelength: 633 nm).

(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) And 1.0 g of CHO manufactured by Toa Gosei Co., Ltd. and a photoacid generator Rhodosil Photoinitiator 2074 (manufactured by Rhodia, CAS # 178233-72-2) (1.36E-2 g in 0.1 mL of ethyl acetate) were 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.

In Examples 1 to 7, when light is applied to the photosensitive resin composition, an acid is generated from the photoacid generator, and the 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 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 according to GPC measurement. Further, according to the identification by NMR, the molar ratio of each structural unit was 50 mol% for the hexylnorbornene structural unit and 50 mol% for the phenyldimethylnorbornenemethoxysilane structural unit. The refractive index by Metricon was 1.53 (measurement wavelength: 633 nm).

(2) Production of photosensitive resin composition A photosensitive resin composition was obtained in the same manner as in Example 1 except that norbornene resin B was used instead of 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 0.1mL) and add Then, it was filtered with a 0.2 μm PTFE filter to prepare a clean photosensitive resin composition varnish for the 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 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 0.1 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 0.1 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) 2.4 g, the above catalyst precursor (2.6E-2 g), photoacid generator Rhodorsil Photoinitiator 2074 (manufactured by Rhodia, CAS # 178233-72-2) (1.36E-2 g, in ethyl acetate 0.1 mL) ) 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 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 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 films having the same length are bent is defined as “bending loss”. As shown in FIG. 12, the insertion loss and the optical waveguide film when the optical waveguide film is curved are linear. The “bending loss” is expressed by the difference from the insertion loss when the shape is made.
Insertion loss [dB] =-10 log (outgoing light intensity / incident light intensity)
Bending loss = (insertion loss on a curve)-(insertion loss on a straight line)

As apparent from Table 2, Examples 1 and 8-12 showed low optical loss and excellent optical waveguide performance.
In addition, Examples 1 and 8-12 showed small light loss after high-temperature and high-humidity treatment and after reflow treatment, and excellent 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.

The optical waveguide structure of the present invention has a wide range of optical circuit (optical waveguide pattern) and electrical circuit design, good yield, high optical transmission performance, excellent reliability and durability, and versatility. Rich. Therefore, the present invention can be used for various electronic parts, electronic devices, and the like, and therefore the present invention is extremely useful in industry.

DESCRIPTION OF SYMBOLS 1 Optical waveguide structure 2 Optical waveguide main body 3 Inclined surface 4a, 4b, 4c, 4d, 4e, 4f, 4g Optical path conversion part 5a, 5b, 5c, 5d, 5e, 5f, 5g Reflecting surface 61, 62, 63, 64 , 65 Light emitting element 610, 620, 630, 640, 650 Light emitting part 71, 711, 712 Transmitted light 72 Transmitted light 73 Transmitted light 74, 741, 742 Transmitted light 75 Transmitted light 76 Transmitted light 9 Optical waveguide 90 Laminate (optical waveguide) )
91 Cladding layer 92 Core layer laminated part 93 Core layer 94 Core part 941 Branch part 942, 943, 944, 945, 946, 947, 948 Outgoing end 95 Cladding part 96 Cladding layer 961, 962, 963, 964, 965 Exposed surface ( Exposed end face)
900 Varnish (core layer forming material)
910 Film M Mask

Claims (21)

1. An optical waveguide body having a core part forming an optical path and a clad part formed on an outer periphery of the core part and having a refractive index different from the core part;
   The core portion is three-dimensionally arranged in the optical waveguide body,
   The core part is
   (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 claim 1, wherein the cyclic ether group (B) is an oxetanyl group or an epoxy group.
3. 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).
   [Chemical 1]
   

   
4. 4. The optical waveguide structure according to claim 1, wherein the core portion has a portion extending in at least one of X, Y, and Z directions orthogonal to each other.
5. The optical waveguide structure according to any one of claims 1 to 4, wherein the core portion has a portion extending in at least two of the X, Y, and Z directions orthogonal to each other.
6. The optical waveguide structure according to any one of claims 1 to 5, wherein the optical waveguide body has a portion in which a clad layer and a core layer constituting the clad portion are alternately laminated.
7. The optical waveguide according to any one of claims 1 to 6, wherein the optical waveguide body has a portion in which two or more laminated bodies each formed by joining the clad layers constituting the clad portion are overlapped on both surfaces of the core layer. Structure.
8. The optical waveguide structure according to any one of claims 1 to 7, wherein the optical waveguide body has a core layer laminated portion in which a plurality of the core layers are laminated.
9. The optical waveguide structure according to claim 6, further comprising a portion configured to transmit and receive transmission light between the core portions formed between the different core layers.
10. The optical waveguide structure according to any one of claims 1 to 9, further comprising an optical path conversion unit that bends an optical path of transmission light transmitted through the core unit.
11. The optical waveguide structure according to claim 10, wherein the optical path conversion unit has a reflection surface that reflects at least a part of the transmission light.
12. The optical waveguide structure according to claim 10 or 11, wherein the optical path conversion unit has a function of dividing an optical path of the transmission light in a plurality of directions.
13. The core part is arranged so that transmission light incident on a predetermined part of the core part from the outside of the optical waveguide body does not intersect with other parts of the core part. The optical waveguide structure described.
14. The optical waveguide structure according to any one of claims 1 to 13, wherein the core portion has a portion where an optical path branches and / or merges.
15. When transmission light is incident on a predetermined part of the core part from one incident direction of X, Y, and Z directions orthogonal to each other, the transmission light is orthogonal to the incident direction from the other part of the core part The optical waveguide structure according to any one of claims 1 to 14, wherein the optical waveguide structure is configured to emit light to a light source.
16. The optical waveguide structure according to any one of claims 1 to 15, wherein at least one surface of the optical waveguide body is configured by an inclined surface inclined with respect to a transverse section of the core portion.
17. The optical waveguide structure according to claim 1, comprising at least one element having a light emitting part or a light receiving part and a terminal.
18. The optical waveguide structure according to claim 17, comprising two or more elements that operate independently of each other, operate in conjunction with each other, or operate synchronously.
19. The optical waveguide structure according to claim 1, comprising a conductor layer.
20. The optical waveguide structure according to claim 17, further comprising a conductor layer, wherein the terminal is electrically connected to the conductor layer.
21. An electronic apparatus comprising the optical waveguide structure according to any one of claims 1 to 20.

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