Resin composition for reinforcing optical element junctions and optical module using the same

Abstract

Provided is an optical module in which a space between a light-emitting part (or a light-receiving part) 11a in an optical element 11 and an insulation layer 1 in an electric circuit board E is filled with a cured product of a light-transmissive resin composition that contains only a non-antimony curing agent component as a curing agent component (i.e., an optical element joining-reinforcing resin cured product X) and a joined part between the optical element 11 and the electric circuit board E is reinforced by the cured product. The problem of black discoloration which occurs when a light-transmissive resin composition is used in contact with the light-emitting part or the light-receiving part in the optical element can be resolved, and the problem of reduction in output which is caused as the result of the inhibition of the light emission and light reception of the optical element due to the black discoloration can also be resolved.

Description

[Technical Field]

[0001] The present invention relates to a resin composition for reinforcing the bonding of optical elements, which is used to reinforce the mounting (bonding between the optical element and the electric circuit board) when mounting an optical element such as a light-emitting element or a light-receiving element on an electric circuit board, and to an optical module using the resin composition. [Background technology]

[0002] As an optical module in which optical elements such as light-emitting elements and light-receiving elements are mounted on an optical waveguide, for example, the following optoelectronic hybrid board (first conventional example) has been proposed. This optoelectronic hybrid board includes an electric circuit board having electrical wiring formed on the surface of an insulating layer, an optical waveguide (first cladding layer, core (optical wiring), second cladding layer) laminated on the back surface of the insulating layer of the electric circuit board (the surface opposite to the surface on which the electrical wiring is formed), and a light-emitting element and a light-receiving element mounted on portions of the surface on which the electrical wiring is formed corresponding to both ends of the optical waveguide. In this optoelectronic hybrid board, both ends of the optical waveguide are formed on inclined surfaces inclined at 45° with respect to the longitudinal direction of the core (the direction of light propagation), and the portions of the core located on the inclined surfaces serve as light-reflecting surfaces (mirrors). The insulating layer is optically transparent, allowing light to propagate through the insulating layer between the light-emitting element and the light-reflecting surface at one end and between the light-receiving element and the light-reflecting surface at the other end.

[0003] Light propagates in the above-mentioned opto-electric hybrid board as follows. First, light is emitted from the light-emitting element toward the light-reflecting surface at one end. After passing through the insulating layer, the light passes through the first cladding layer at one end of the optical waveguide, is reflected by the light-reflecting surface at one end of the core (changing its optical path by 90°), and travels longitudinally within the core. The light that has propagated within the core is then reflected by the light-reflecting surface at the other end of the core (changing its optical path by 90°) and travels toward the light-receiving element. Next, the light passes through the first cladding layer at the other end, is emitted, passes through the insulating layer, and is received by the light-receiving element.

[0004] However, there is a problem in that the light emitted from the light-emitting element is diffused or reflected before reaching the light-receiving element, reducing the amount of light that is effectively propagated, resulting in a decrease in the output of the optical-electrical hybrid board.

[0005] Therefore, various proposals have been made to reduce the propagation loss of light (second conventional example) by providing a lens between an optical element such as a light-emitting element or a light-receiving element and an optical waveguide in the configuration shown in the first conventional example (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-40011 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the lens-equipped device as in the second conventional example has a complex structure, a large number of parts, and a complicated manufacturing process, which creates a problem in terms of cost, and there is room for improvement in this regard.

[0008] Therefore, the present inventors investigated the use of an optically transparent resin composition containing an epoxy resin as a main component as an underfill for optical elements such as light-emitting elements and light-receiving elements in the configuration shown in the first conventional example. That is, by using the optically transparent resin composition to fill the gap between the light-emitting or light-receiving part of the optical element and the insulating layer of the electric circuit board, the inventors investigated the possibility of simplifying the structure and manufacturing process, reducing light propagation loss, and further reinforcing the joint between the optical element and the electric circuit board. However, when an optical module was actually fabricated in the manner described above, the underfill near the light-emitting and light-receiving sections of the optical element turned black over time, hindering light emission and reception, and this phenomenon resulted in a decrease in the output of the optical module.

[0009] The present invention has been made in consideration of the above circumstances, and provides a resin composition for reinforcing the junction of optical elements, which can solve the problem of blackening when a light-transmitting resin composition is used in contact with the light-emitting or light-receiving part of an optical element, and can solve the problem of reduced output due to the blackening inhibiting the light emission and reception of the optical element, and an optical module using the above resin composition. [Means for solving the problem]

[0010] The present inventors have conducted extensive research to solve the above-mentioned problems. During the course of their research, they have discovered that the problem of blackening when a light-transmitting resin composition is used in contact with the light-emitting or light-receiving portion of an optical element is caused by an antimony-based curing agent that is commonly used as a curing agent component of light-transmitting resin compositions (particularly a curing agent component of epoxy resins). That is, as shown in Figure 5, SbF6, derived from the antimony-based curing agent, contained in the cured product Y of the light-transmitting resin composition, - Research by the present inventors has revealed that ions are attracted to the positively charged light-emitting portion (or light-receiving portion) 11a of the optical element 11 (in the direction of the arrow in the figure), segregating (ion migration), and this segregation appears as the black discoloration. Therefore, the present inventors have discovered that the desired object can be achieved by using only a non-antimony-based curing agent component as the curing agent component of the light-transmitting resin composition used for the above-mentioned application, contrary to conventional technical common sense.

[0011] That is, the gist of the present invention is the following [1] to

[11] . [1] A resin composition for reinforcing the bond between an optical element and an electric circuit board, which is used in contact with the light-emitting or light-receiving part of the optical element, characterized in that the resin composition for reinforcing the bond between the optical element is a light-transmitting resin composition containing only a non-antimony-based curing agent component as a curing agent component. [2] The resin composition for reinforcing a bond between optical elements according to [1], wherein 50% by weight or more of the resin components of the optically transparent resin composition is an epoxy resin. [3] The resin composition for reinforcing bonding of optical elements according to [2], wherein the optically transparent resin composition further contains an acrylic resin. [4] The resin composition for reinforcing bonds of optical elements according to any one of [1] to [3], wherein the non-antimony-based curing agent component is a phosphorus-based curing agent component. [5] The resin composition for reinforcing optical element bonds according to any one of [1] to [3], wherein the non-antimony-based curing agent component is a boron-based curing agent component. [6] The resin composition for reinforcing optical element bonds according to any one of [1] to [3], wherein the non-antimony-based curing agent component is an amine-based curing agent component. [7] The resin composition for reinforcing a bond between optical elements according to any one of [1] to [6], wherein the light-transmitting resin composition exhibits at least one of ultraviolet curing and heat curing properties. [8] An optical module comprising an electric circuit board, an optical element bonded to the electric circuit board, and a cured resin for reinforcing the bond of an optical element, which reinforces the bond between the optical element and the electric circuit board and is placed in contact with the light-emitting portion or the light-receiving portion of the optical element, wherein the cured resin for reinforcing the bond of an optical element is a cured product made from a resin composition for reinforcing the bond of an optical element according to any one of [1] to [7]. [9] An optical module according to [8], wherein the optical element is bonded with the light-emitting or light-receiving part of the optical element facing the electric circuit board, and the cured resin for reinforcing the optical element bond is used as an underfill for the optical element.

[10] An optical module according to [8], in which the optical element is bonded with the light-emitting or light-receiving part of the optical element facing away from the electric circuit board, and the cured resin for reinforcing the optical element bond is used as a covering material for the optical element.

[11] The optical module according to any one of [8] to

[10] , further comprising an optical waveguide, the core of which is optically coupled to the light emitting portion or the light receiving portion of the optical element. [Effects of the Invention]

[0012] As described above, the resin composition for reinforcing the bonding of optical elements of the present invention is composed of a light-transmitting resin composition containing only a non-antimony-based curing agent component as a curing agent component, and can solve the problem of blackening when the light-transmitting resin composition is used in contact with the light-emitting portion or light-receiving portion of an optical element, and can solve the problem of the blackening interfering with the light emission and reception of the optical element. The optical module of the present invention is an optical module comprising an electric circuit board, an optical element bonded onto the electric circuit board, and a cured resin for reinforcing the bond of the optical element, which reinforces the bond between the optical element and the electric circuit board and is placed in contact with the light-emitting portion or the light-receiving portion of the optical element, and since the cured resin for reinforcing the bond of the optical element is a cured product made from the specific resin composition for reinforcing the bond of the optical element, the problem of blackening that occurs over time with use is solved, and the problem of reduced output of the optical module caused by this phenomenon can be solved. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a longitudinal sectional view schematically showing an example of an optical module of the present invention. [Figure 2] FIG. 10 is a longitudinal sectional view schematically showing another example of the optical module of the present invention. [Figure 3] FIG. 10 is a longitudinal sectional view schematically showing another example of the optical module of the present invention. [Figure 4] 5(a) to 5(d) are explanatory views schematically showing the manufacturing process of the optical module of the present invention. [Figure 5]1 is an explanatory diagram schematically illustrating a phenomenon that occurs when a conventional resin composition for reinforcing the bond of an optical element is used. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, an embodiment of the present invention will be described in detail, but the present invention is not limited to this embodiment.

[0015] As described above, the resin composition for reinforcing junctions of optical elements of the present invention (hereinafter sometimes abbreviated as "the resin composition of the present invention") is a resin composition for reinforcing junctions of optical elements that reinforces the junction between an optical element and an electric circuit board and is used in contact with the light-emitting or light-receiving part of the optical element. The resin composition for reinforcing junctions of optical elements is characterized in that it is a light-transmitting resin composition containing only a non-antimony-based curing agent component as a curing agent component. In the present invention, "light-transmitting" refers to a transmittance of 40% or more at a wavelength of 400 nm when the resin composition is cured and formed into a film with a thickness of 100 μm, preferably a transmittance of 60% or more, and more preferably a transmittance of 80% or more. As described above, the resin composition of the present invention is intended to reinforce the joint between an optical element and an electric circuit board and to be used in contact with the light-emitting portion or the light-receiving portion of the optical element. Therefore, resin compositions used for purposes other than this are not included in the scope of the present invention. Furthermore, since the resin composition of the present invention reinforces the joint between the optical element and the electric circuit board and is used in contact with the light-emitting portion or the light-receiving portion of the optical element, a resin composition having either thermosetting or ultraviolet curing properties is typically used. In particular, from the viewpoint of more efficiently manufacturing the optical module of the present invention, it is preferable that the resin composition of the present invention has both thermosetting and ultraviolet curing properties. Note that the above properties are usually determined by the combination of the resin component (main component) and the curing agent component.

[0016] The resin component of the resin composition of the present invention is a resin exhibiting optical transparency. Examples of such resins include epoxy resins, acrylic resins, silicone resins, and urethane resins, which may be used alone or in combination. Among these, epoxy resins are preferred. The resin composition of the present invention is typically a liquid that exhibits fluidity at room temperature (25°C), and is diluted with an organic solvent as needed. Furthermore, it is preferred that 50% by weight or more of the resin component in the resin composition of the present invention be epoxy resin, more preferably 65% ​​by weight or more of the resin component, and even more preferably 80% by weight or more of the resin component be epoxy resin. Epoxy resins exhibit both thermosetting and UV-curing properties when combined with, for example, a phosphorus-based or boron-based curing agent, but only exhibit thermosetting properties when combined with an amine-based curing agent. Therefore, to achieve both thermosetting and UV-curing properties when using an amine-based curing agent, it is preferable to use an acrylic resin in combination with the epoxy resin. The proportion of the acrylic resin in the combined use is preferably 5 to 50% by weight of the resin components, more preferably 10 to 25% by weight of the resin components.

[0017] The epoxy resin may be a bisphenol epoxy resin, an alicyclic epoxy resin, a novolac epoxy resin, or the like, and may be used alone or in combination. Of these, bisphenol epoxy resins and alicyclic epoxy resins are preferred. Such epoxy resins generally have an epoxy equivalent of 100 to 1000 and a softening point of 120°C or less. The bisphenol epoxy resin and alicyclic epoxy resin preferably account for 50% by weight or more of the total epoxy resin.

[0018] As the curing agent component of the resin composition of the present invention, only a non-antimony curing agent component is used. Note that, in the present invention, the curing agent component includes not only so-called curing agents (polymerization initiators) such as heat curing agents and ultraviolet curing agents, but also curing accelerators. Examples of the non-antimony-based curing agent component include phosphorus-based curing agent components, boron-based curing agent components, amine-based curing agent components, acid anhydride-based curing agent components, and phenol-based curing agent components, and these may be used alone or in combination of two or more. When the resin component contains an acrylic resin, it is preferable to use a radical polymerization initiator. Examples of the radical polymerization initiator include a phosphorus-based curing agent component, a phenone-based curing agent component, an ester-based curing agent component, a peroxide-based curing agent component, a nitrogen-based curing agent component, and a sulfur-based curing agent component, and these may be used alone or in combination of two or more.

[0019] Examples of the phosphorus-based curing agent component include triarylsulfonium phosphorus anion salt (manufactured by San-Apro Co., Ltd., CPI-200K) and benzylmethyl-p-methoxycarbonyloxyphenylsulfonium hexafluorophosphate (manufactured by Sanshin Chemical Industry Co., Ltd., SAN-AID SI-300), which may be used alone or in combination of two or more.

[0020] Furthermore, examples of the boron-based curing agent component include triarylsulfonium borate salts (manufactured by San-Apro Co., Ltd., CPI-310B) and benzylmethyl-p-hydroxyphenylsulfonium borate salts (manufactured by Sanshin Chemical Industry Co., Ltd., SAN-AID SI-B3), which may be used alone or in combination of two or more.

[0021] Examples of the amine-based curing agent component include tertiary amines (manufactured by Mitsubishi Chemical Corporation, jER Cure 3010), modified aliphatic amines (manufactured by Mitsubishi Chemical Corporation, jER Cure T, TO184, U, 3012PF, 3050, XD580), modified alicyclic amines (manufactured by Mitsubishi Chemical Corporation, jER Cure 113, WA), ketimines (manufactured by Mitsubishi Chemical Corporation, jER Cure H3, H30), and imidazoles (manufactured by Mitsubishi Chemical Corporation, jER Cure IBM112, P200H50), which may be used alone or in combination. Among these, modified alicyclic amines are preferred, and jER Cure WA, manufactured by Mitsubishi Chemical Corporation, is particularly preferred because of its high transparency and ability to cure resins with a small amount added.

[0022] The amount of the curing agent component blended is preferably set in the range of 3 to 60 parts by weight, more preferably 5 to 45 parts by weight, and even more preferably 5 to 30 parts by weight, per 100 parts by weight of the resin component (main component).

[0023] The resin composition of the present invention has optical transparency and does not contain any antimony-based compounds. It contains the resin component and curing agent component described above. In addition, the resin composition may contain, as necessary, a curing catalyst, a dye, a modifier, a discoloration inhibitor, an antiaging agent, a release agent, a reactive or non-reactive diluent, and the like.

[0024] The resin composition of the present invention can be prepared, for example, by blending and mixing the resin component, curing agent component, etc., and then, if necessary, kneading or melt-mixing the mixture with a kneader.

[0025] The resin composition of the present invention thus prepared can be used to manufacture the optical module of the present invention. The optical module of the present invention includes an electric circuit board, an optical element bonded to the electric circuit board, and a cured resin for reinforcing the bond between the optical element and the electric circuit board, the cured resin being in contact with the light-emitting portion or the light-receiving portion of the optical element, and the cured resin for reinforcing the bond between the optical element is a cured product made from the resin composition of the present invention.

[0026] The optical module may have the configurations shown in FIGS. 1 to 3, for example. 1 and 2 show examples in which the optical element is bonded with its light-emitting or light-receiving portion facing the electric circuit board side of the opto-electric hybrid board, and the cured resin for reinforcing the bond of the optical element is used as an underfill for the optical element. Also, Fig. 3 shows an example in which the optical element is bonded with its light-emitting or light-receiving portion facing the side opposite to the electric circuit board side, and the cured resin for reinforcing the bond of the optical element is used as a covering material for the optical element.

[0027] 1 and 2, reference numeral 11 denotes an optical element, 11a denotes a light-emitting portion (or a light-receiving portion), and 11b denotes bumps. As shown in the figures, the optical element 11 is mounted with its light-emitting portion (or light-receiving portion) 11a facing the electric circuit board E, so as to be connected to the electric circuit of the electric circuit board E via the bumps 11b and mounting pads 2a. The electric circuit board E is formed by forming an electric circuit (not shown) and the mounting pads 2a on the surface of an insulating layer 1 having optical transparency. The space between the light-emitting portion (or light-receiving portion) 11a of the optical element 11 and the insulating layer 1 of the electric circuit board E is filled with a cured product of the resin composition of the present invention prepared as described above (cured resin X for reinforcing the bond of optical elements). As shown in the figure, the cured resin X for reinforcing the bond of optical elements reinforces the joint between the optical element 11 and the electric circuit board E and is provided in contact with the light-emitting portion (or light-receiving portion) 11a of the optical element 11. This embodiment also includes an optical waveguide W, and the core 7 of the optical waveguide W is optically coupled to the light-emitting portion (or light-receiving portion) 11a of the optical element 11 via the cured resin X for reinforcing optical element coupling and the insulating layer 1. The optical waveguide W is composed of a laminate of a first cladding layer 6, a core 7, and a second cladding layer 8. As shown in the figure, one end of the optical waveguide W corresponding to the optical element 11 is formed on an inclined surface inclined at 45° with respect to the longitudinal direction of the core 7, and the portion of the core 7 located on this inclined surface serves as a light-reflecting surface 7a. With this configuration, the light-emitting portion (or light-receiving portion) 11a of the optical element 11 is optically coupled to the core 7. When 11a is the light-emitting portion, an optical signal L flows through the core 7 of the optical waveguide W in the direction indicated by the arrow in the figure. When 11a is the light-receiving portion, the optical signal L flows in the opposite direction to the arrow in the figure. In this embodiment, a reinforcing metal layer M is provided between the electric circuit board E and the optical waveguide W. The metal layer M is provided with a through hole 5 so as not to interfere with the optical signal L transmitted and received at the light emitting section (or light receiving section) 11a of the optical element 11, and a first clad layer 6 is inserted in the through hole 5 to fill it.

[0028] 2 is a modified example of Fig. 1, in which the cured resin X for reinforcing the bond of an optical element not only serves as an underfill for the optical element 11 but also as a mold that covers the entire optical element 11. By covering the entire optical element 11 in this way, the bond reinforcement of the optical element 11 is enhanced, durability is improved, and reliability is enhanced.

[0029] In FIG. 3, the optical element 11 is bonded to the electric circuit board E' via an adhesive layer 14, with the light-emitting portion (or light-receiving portion) 11a of the optical element 11 facing away from the electric circuit board E'. The optical element 11 is mounted so as to be connected to the electric circuit of the electric circuit board E' via wires 12 and connection terminals 13. A cured product of the resin composition of the present invention prepared as described above (cured resin X for reinforcing the bond of an optical element) is used as a covering material for the optical element 11 mounted in this manner. As shown in the figure, the cured resin X for reinforcing the bond of an optical element reinforces the joint between the optical element 11 and the electric circuit board E' and is provided in contact with the light-emitting portion (or light-receiving portion) 11a of the optical element 11. The electric circuit board E' is formed by forming an electric circuit (not shown) and connection terminals 13 on the surface of the insulating layer 1'. The insulating layer 1' does not need to be optically transparent. In this embodiment, a lens 15 and an optical fiber 16 are provided as shown in the figure. A portion of the lens 15 is formed on an inclined surface (light-reflecting surface 15a) inclined at 45° with respect to the optical path of the light-emitting portion (or light-receiving portion) 11a of the optical element 11. With this configuration, the light-emitting portion (or light-receiving portion) 11a of the optical element 11 is optically coupled to the optical fiber 16 via the cured resin X for reinforcing optical element bonding and the lens 15, and an optical signal from the optical element 11 flows through the optical fiber 16. That is, when 11a is the light-emitting portion, the optical signal L flows through the core 7 of the optical waveguide W in the direction indicated by the arrow in the figure, and when 11a is the light-receiving portion, the optical signal L flows in the opposite direction to the direction indicated by the arrow in the figure.

[0030] The method for underfilling or coating an optical element using the resin composition of the present invention is not particularly limited, and can be carried out by a known molding method such as ordinary transfer molding or casting. FIG. 4 is a schematic diagram illustrating an example of a manufacturing process for the optical module of the present invention (the optical module shown in FIG. 1 ), with the process proceeding in the order of (a) to (d) in the figure. First, as shown in (a), an optical element 11 is mounted on an electric circuit board E, and then, as shown in (b), an underfill X′ (the resin composition of the present invention) is applied. The application is performed using a syringe or the like. Then, UV (ultraviolet rays) are irradiated in the direction of arrow U shown in (c) to partially cure the underfill X′ and temporarily fix the optical element 11. Then, as shown in (d), the uncured portions of the underfill X′ (portions not irradiated with UV) are thermally cured by heating to form a completely cured product (cured resin product X for reinforcing the bond of the optical element). In this manner, the optical element 11 is permanently fixed. The ultraviolet irradiation conditions for ultraviolet curing the resin composition of the present invention are 4,000 to 30,000 mJ / cm using a UV irradiation device. 2 It is preferable that ultraviolet irradiation is carried out at a dose of 12,000 to 24,000 mJ / cm using the above-mentioned device. 2 The heating conditions for thermally curing the resin composition of the present invention are preferably heating in an oven at 25 to 150°C for 10 to 180 minutes, and more preferably heating in the above-mentioned device at 80 to 120°C for 30 to 120 minutes. When an optical module is manufactured by the above-described process, it is preferable that the underfill X' (the resin composition of the present invention) has both heat-curable and ultraviolet-curable properties. Although the above-described temporary fixing step can be omitted, it is preferable to include the above-described temporary fixing step in order to improve yield.

[0031] [Formation of Electric Circuit Board E] 1 and 2, first, a metal sheet material is prepared for forming the metal layer M. Examples of materials for forming this metal sheet material include stainless steel and 42 alloy, and among these, stainless steel is preferred from the viewpoint of dimensional accuracy, etc. The thickness of the metal sheet material (metal layer M) is set within the range of 10 to 100 μm, for example.

[0032] Next, a photosensitive insulating resin is applied to the surface of the metal sheet material, and a predetermined pattern of insulating layer 1 is formed by photolithography. Examples of materials for forming this insulating layer 1 include synthetic resins such as polyimide, polyethernitrile, polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, and polyvinyl chloride, and silicone-based sol-gel materials. The thickness of the insulating layer 1 is set within the range of 10 to 100 μm, for example.

[0033] Next, electrical wiring (not shown) and mounting pads 2a are formed on the insulating layer 1 by, for example, a semi-additive method, a subtractive method, or the like.

[0034] Furthermore, a photosensitive insulating resin such as polyimide resin is usually applied to the electrical wiring portion, and a coverlay is formed by photolithography. In this way, an electric circuit board E is formed on the surface of the metal sheet material.

[0035] Thereafter, the metal sheet material is subjected to etching or the like to form through holes 5 in the metal sheet material, thereby forming the metal layer M.

[0036] [Formation of optical waveguide W] 1 and 2, when an optical waveguide W is formed on the back surface of a laminate of the electric circuit board E and the metal layer M, a photosensitive resin, which is a material for forming the first cladding layer 6, is first applied to the back surface (the bottom surface in the figures) of the laminate, and the first cladding layer 6 is formed by photolithography. As shown in the figures, the first cladding layer 6 is formed in a state in which the through holes 5 of the metal layer M are filled. The thickness of the first cladding layer 6 (thickness from the back surface of the metal layer M) is set, for example, in the range of 5 to 80 μm. When the optical waveguide W is formed (when the first cladding layer 6, the core 7 described below, and the second cladding layer 8 described below are formed), the back surface of the laminate is faced upward. Next, a photosensitive resin, which is a material for forming the core 7, is applied to the surface (the lower surface in the figure) of the first cladding layer 6, and the core 7 is formed in a predetermined pattern by photolithography. As a result, the dimensions of the core 7 are set, for example, in the range of 20 to 100 μm in width, 20 to 100 μm in thickness, and 0.5 to 100 cm in length. Then, a material for forming the second cladding layer 8 is applied to the surface (the lower surface in the figure) of the first cladding layer 6 so as to cover the core 7, and the second cladding layer 8 is formed by a photolithography method. The thickness of this second cladding layer 8 (thickness from the interface with the core 7) is set in the range of 3 to 50 μm, for example. The material for forming the second cladding layer 8 can be, for example, the same photosensitive resin as that for the first cladding layer 6. Thereafter, an inclined surface (light reflecting surface 7a) inclined at 45° with respect to the longitudinal direction of the core 7 is formed on the optical waveguide W formed as described above, for example, by laser processing, etc. In this way, the optical waveguide W is formed on the back surface of the metal layer M. The photosensitive resins are prepared so that the refractive index of the core 7 is greater than the refractive indexes of the first cladding layer 6 and the second cladding layer 8 described below.

[0037] The optical module of the present invention can be used as an optical transceiver such as QSFP (Quad Small Form-factor Pluggable) or OSFP (Octal Small Form Factor Pluggable), which are communication interface standards for optical communications, an AOC (Active Optical Cable), an AOC for consumer use, or internal wiring for electrical devices such as smartphones, tablets, and PCs (Personal Computers). [Example]

[0038] Next, examples will be described together with comparative examples, but the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

[0039] [Example 1] 100 parts by weight of epoxy resin (jER828, manufactured by Mitsubishi Chemical Corporation) and phosphorus-based curing agent (2 parts by weight of CPI-200K manufactured by San-Apro Co., Ltd. and 4 parts by weight of SAN-AID SI-300 manufactured by Sanshin Chemical Industry Co., Ltd.) were premixed, and then the mixture was melt-mixed and kneaded in a kneader. This was then cooled to 23°C to prepare a light-transmitting resin composition (underfill).

[0040] An optical module was manufactured using the resin composition according to the steps shown in (a) to (d) of Figure 4. Specifically, first, an optical element 11 was mounted on an electric circuit board E as shown in (a), and then the resin composition (underfill X') prepared as shown in (b) was applied. Next, a spot UV irradiation device (Ushio Inc., SP-9) was used to irradiate the underfill with UV (ultraviolet rays) at a dose of 12,000 mJ / cm as shown in (c). 2 The UV-irradiated portion of the underfill X' was cured to temporarily fix the optical element 11. After that, the underfill X' was thermally cured by heating in an oven at 100°C for 60 minutes, as shown in (d), to form a completely cured product (cured resin X for reinforcing the bond of the optical element), and the optical element 11 was permanently fixed.

[0041] [Example 2] 100 parts by weight of epoxy resin (jER828, manufactured by Mitsubishi Chemical Corporation) and boron-based curing agent (2 parts by weight of CPI-310B manufactured by San-Apro Co., Ltd. and 4 parts by weight of SAN-AID SI-B3 manufactured by Sanshin Chemical Industry Co., Ltd.) were premixed, and then the mixture was melt-mixed and kneaded in a kneader. This was then cooled to room temperature to prepare a light-transmitting resin composition (underfill). An optical module was produced in the same manner as in Example 1, except that the optically transparent resin composition prepared above was used instead of the optically transparent resin composition of Example 1.

[0042] [Example 3] 100 parts by weight of an epoxy resin (jER828, manufactured by Mitsubishi Chemical Corporation) and 25 parts by weight of an amine-based curing agent (jER Cure WA, manufactured by Mitsubishi Chemical Corporation) were premixed, then melted and mixed in a kneader, and cooled to room temperature to prepare a light-transmitting resin composition (underfill). Then, an optical module was manufactured in the same manner as in Example 1, except that the optically transparent resin composition prepared above was used instead of the optically transparent resin composition of Example 1, and the UV irradiation step shown in Example 1 (the step shown in Figure 4(b)) was omitted.

[0043] [Example 4] 90 parts by weight of epoxy resin (jER828, manufactured by Mitsubishi Chemical Corporation), 10 parts by weight of acrylic resin (ABE-400, manufactured by Shin-Nakamura Chemical Co., Ltd.), 22.5 parts by weight of an amine-based curing agent (jER Cure WA, manufactured by Mitsubishi Chemical Corporation), and 0.2 parts by weight of a radical initiator (Irgacure 819, manufactured by BASF Japan Ltd.) were premixed, and then the mixture was melt-mixed and kneaded in a kneader. This was then cooled to room temperature to prepare a light-transmitting resin composition (underfill). An optical module was produced in the same manner as in Example 1, except that the optically transparent resin composition prepared above was used instead of the optically transparent resin composition of Example 1.

[0044] [Comparative Example 1] 100 parts by weight of an epoxy resin (jER828, manufactured by Mitsubishi Chemical Corporation), 2 parts by weight of an antimony-based curing agent (CPI-101A, manufactured by San-Apro Co., Ltd.), and 4 parts by weight of an antimony-based curing agent (SAN-AID SI-60, manufactured by Sanshin Chemical Industry Co., Ltd.) were premixed, and then melt-mixed by kneading in a kneader. The mixture was then cooled to room temperature to prepare a light-transmitting resin composition (underfill). Then, an optical module was manufactured in the same manner as in Example 1, except that the optically transparent resin composition prepared above was used instead of the optically transparent resin composition of Example 1, and the UV irradiation step shown in Example 1 (the step shown in Figure 4(b)) was omitted.

[0045] <Presence or absence of blackening> Each optical module manufactured in this manner was placed in an 85°C x 85% RH environment for 500 hours with a current of 10 mA applied, and then the cured product of each resin composition (underfill) was visually evaluated for blackening due to segregation of the curing agent, according to the following evaluation criteria. ◯ (very good): No blackening due to segregation from the hardener is observed. △ (good): Blackening due to segregation of hardener is observed to a degree that does not affect the output reduction of the optical module. × (poor): Blackening due to segregation from the hardener was observed to an extent that it affected the output reduction of the optical module.

[0046] [Table 1]

[0047] From the results in Table 1 above, the optical module of the example shows almost no blackening of the underfill after long-term use, and there is no risk of this resulting in a decrease in the output of the optical module. In contrast, the optical module of the comparative example shows results that raise concerns about a decrease in the output of the optical module due to blackening of the underfill after long-term use. When the light-transmitting resin compositions of the Examples and Comparative Examples were used as coating materials for optical elements (see FIG. 3), the same results as those of the Examples and Comparative Examples were obtained.

[0048] Although the above examples show specific embodiments of the present invention, the examples are merely illustrative and should not be construed as limiting. Various modifications that are obvious to those skilled in the art are intended to fall within the scope of the present invention. [Industrial Applicability]

[0049] The optical module of the present invention can be used as an optical transceiver such as an OSFP (Octal Small Form Factor Pluggable) or QSFP (Quad Small Form Factor Pluggable), which is a communication interface standard for optical communications, an AOC (Active Optical Cable), an AOC for consumer use, or internal wiring in electrical devices such as smartphones, tablets, and PCs (Personal Computers). [Explanation of symbols]

[0050] E. Electrical circuit board X Resin hardened material for reinforcing the bonding of optical elements 1. Insulation layer 11 Optical elements 11a Light emitting unit (or light receiving unit)

Claims

1. A resin composition for reinforcing a joint between an optical element and an electric circuit board, and used in contact with a light-emitting portion or a light-receiving portion of the optical element, the resin composition for reinforcing a joint between an optical element and an electric circuit board, the resin composition for reinforcing a joint between an optical element and an electric circuit board being made of a light-transmitting resin composition containing only a non-antimony-based curing agent component as a curing agent component, the amount of the non-antimony curing agent is set in the range of 3 to 30 parts by weight per 100 parts by weight of the resin component, A resin composition for reinforcing the bonding of optical elements, characterized in that the non-antimony-based curing agent contains a curing agent selected from the group consisting of phosphorus-based curing agents, boron-based curing agents, and modified alicyclic amine-based curing agents.

2. 2. The resin composition for reinforcing the bond of an optical element according to claim 1, wherein 50% by weight or more of the resin component of said light-transmitting resin composition is an epoxy resin.

3. 3. The resin composition for reinforcing the bond of optical elements according to claim 2, wherein the light-transmitting resin composition further contains an acrylic resin.

4. 4. The resin composition for reinforcing optical element bonds according to claim 1, wherein the non-antimony-based curing agent component is a phosphorus-based curing agent component.

5. 4. The resin composition for reinforcing bonds of optical elements according to claim 1, wherein the non-antimony-based curing agent component is a boron-based curing agent component.

6. 4. The resin composition for reinforcing optical element bonds according to claim 1, wherein the non-antimony-based curing agent component is a modified alicyclic amine-based curing agent component.

7. 7. The resin composition for reinforcing optical element junctions according to claim 1, wherein the light-transmitting resin composition exhibits at least one of ultraviolet curing and heat curing properties.

8. An optical module comprising: an electric circuit board; an optical element bonded onto the electric circuit board; and a cured resin for reinforcing the bond between the optical element and the electric circuit board, the cured resin reinforcing the bond between the optical element and the electric circuit board, and the cured resin being provided in contact with a light-emitting portion or a light-receiving portion of the optical element, An optical module, wherein the cured resin for reinforcing the bond of an optical element is a cured product made from the resin composition for reinforcing the bond of an optical element according to any one of claims 1 to 7.

9. 9. The optical module according to claim 8, wherein the optical element is bonded with the light-emitting portion or the light-receiving portion of the optical element facing the electrical circuit board, and the cured resin for reinforcing the optical element bond is used as an underfill for the optical element.

10. 9. The optical module according to claim 8, wherein the optical element is bonded with the light-emitting portion or the light-receiving portion of the optical element facing away from the electric circuit board, and the cured resin for reinforcing the optical element bond is used as a covering material for the optical element.

11. 11. The optical module according to claim 8, further comprising an optical waveguide, the core of which is optically coupled to the light emitting portion or the light receiving portion of the optical element.

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