WO2022107762A1

WO2022107762A1 - Optical connection structure

Info

Publication number: WO2022107762A1
Application number: PCT/JP2021/042073
Authority: WO
Inventors: 直人古根川; 誠喜寺地; 正高山路; 雄一辻田; 直幸田中
Original assignee: 日東電工株式会社
Priority date: 2020-11-18
Filing date: 2021-11-16
Publication date: 2022-05-27
Also published as: TW202227867A

Abstract

An optical connection structure (1) is provided with: an optical waveguide (5); an optical fiber (31) that is optically connected to the optical waveguide (5); an electric circuit board (6) and a printed wiring board (8) that are adjacent to the optical waveguide (5); and one adhesive member (4) that adheres the optical waveguide (5), the optical fiber (31), the electric circuit board (6), and the printed wiring board (8).

Description

Optical connection structure

The present invention relates to an optical connection structure.

An optical connection structure for connecting an optical waveguide and an optical fiber is known. For example, an optical connection structure including a substrate, an optical waveguide arranged on one side in the thickness direction of the substrate, an optical fiber having an end surface facing the end surface of the optical waveguide, and an adhesive is proposed (for example, the following). See Patent Document 1). Two adhesives having an optical connection structure are provided. One adhesive contacts the end face of the optical waveguide and the end face of the optical fiber. The other adhesive contacts the concave surface of the recess formed in the substrate and the peripheral surface of the optical fiber. The two adhesives are independent of each other.

Japanese Unexamined Patent Publication No. 2019-8115

Since two adhesives described in Patent Document 1 are provided independently, the shrinkage state at the time of adhesion tends to be different. In this case, the optical fiber is deformed. Then, there is a problem that the optical connection reliability is lowered. Further, since the adhesive body is arranged separately in two, there is a problem that the adhesive strength tends to decrease.

The present invention provides an optical connection structure that suppresses deformation of an optical fiber, improves optical connection reliability, and has excellent adhesive strength.

The present invention (1) is one that adheres an optical waveguide, an optical fiber optically connected to the optical waveguide, a substrate adjacent to the optical waveguide, and the optical waveguide, the optical fiber, and the substrate. Includes an optical connection structure with an adhesive member.

In the present invention, even if the adhesive member shrinks, there is only one adhesive member, which adheres the optical waveguide, the optical fiber, and the substrate. Therefore, it is possible to suppress the deformation of the optical fiber caused by the difference in the contracted state of the two adhesive members as in Patent Document 1. Therefore, the optical connection reliability can be improved. Since there is only one adhesive member in the optical connection structure, it is possible to suppress a decrease in adhesive strength.

As a result, the optical connection structure suppresses the deformation of the optical fiber, improves the optical connection reliability, and has excellent adhesive strength.

The present invention (2) includes the optical connection structure according to (1), wherein the substrate includes a printed wiring board.

In this optical connection structure, the board includes a printed wiring board. The printed wiring board is rigid. Therefore, the reliability of the optical connection between the optical waveguide and the optical fiber can be further improved.

The present invention (3) includes the optical connection structure according to (1) or (2), wherein the substrate includes an electric circuit board arranged on the main surface of the optical waveguide.

In this optical connection structure, the substrate includes an electric circuit board arranged on the main surface of the optical waveguide. Since the optical waveguide and the electric circuit board that can support the main surface of the optical waveguide are bonded by one adhesive member, the strength is excellent.

In the present invention (4), the optical waveguide includes a core and a clad covering the core, and the substrate includes a support plate made of the same material as the clad. The optical connection according to (1). Includes structure.

In this optical connection structure, the substrate includes a support plate made of the same material as the clad. Therefore, the support plate can be easily formed. Further, the support plate is excellent in strength.

The present invention (5) includes the optical connection structure according to (1), wherein the substrate includes a pedestal.

In this optical connection structure, the substrate includes a pedestal. Therefore, the pedestal ensures that the optical waveguide and the optical fiber are aligned. Therefore, the optical connection reliability can be improved.

The present invention (6) further includes a positioning member for positioning the optical fiber, and the positioning member adheres to the optical waveguide, the optical fiber, and the substrate by the one adhesive member (1). The optical connection structure according to any one of (5) is included.

This optical connection structure further includes a positioning member for positioning the optical fiber. Therefore, the positioning member ensures that the optical waveguide and the optical fiber are aligned. Therefore, the optical connection reliability can be improved.

The optical connection structure of the present invention suppresses deformation of the optical fiber, improves optical connection reliability, and has excellent adhesive strength.

1A and 1B are the first embodiments of the optical connection structure of the present invention. FIG. 1A is a plan view. FIG. 1B is a bottom view. 2C to 2E are the first embodiments of the optical connection structure of the present invention. FIG. 2C is a cross-sectional view taken along the line XX of FIG. 1A. FIG. 2D is a cross-sectional view taken along the line YY of FIGS. 1A and 1B. FIG. 2E is a cross-sectional view taken along the line ZZ of FIG. 2C. FIG. 3 is a modification of the first embodiment. FIG. 3 is a cross-sectional view corresponding to FIG. 2C. FIG. 4 is a modification of the first embodiment. FIG. 4 is a cross-sectional view corresponding to FIG. 2C. FIG. 5 is a modification of the first embodiment. FIG. 5 is a cross-sectional view corresponding to FIG. 2E. 6A and 6B are second embodiments of the optical connection structure of the present invention. FIG. 6A is a plan view. FIG. 6B is a cross-sectional view taken along the line XX of FIG. 6A. FIG. 7 is a modification of the second embodiment. FIG. 7 is a cross-sectional view corresponding to FIG. 6B. FIG. 8 is a cross-sectional view of a third embodiment of the optical connection structure of the present invention. FIG. 9 is a cross-sectional view of a modified example of the third embodiment. FIG. 10 is a cross-sectional view of a modified example of the third embodiment. FIG. 11 is a cross-sectional view of a modified example of the third embodiment. FIG. 12 is a cross-sectional view of a modified example of the third embodiment. FIG. 13 is a cross-sectional view of a fourth embodiment of the optical connection structure of the present invention. FIG. 14 is a cross-sectional view of a modified example of the fourth embodiment. FIG. 15 is a cross-sectional view of a modified example of the fourth embodiment. FIG. 16 is a cross-sectional view of a modified example of the fourth embodiment. FIG. 17 is a cross-sectional view of a modified example of the fourth embodiment. FIG. 18 is a cross-sectional view of a fifth embodiment of the optical connection structure of the present invention. FIG. 19 is a cross-sectional view of a modified example of the fifth embodiment. FIG. 20 is a cross-sectional view of a sixth embodiment of the optical connection structure of the present invention. FIG. 21 is a cross-sectional view of a modified example of the sixth embodiment. FIG. 22 is a cross-sectional view of the seventh embodiment of the optical connection structure of the present invention. FIG. 23 is a cross-sectional view of a modified example of the seventh embodiment. FIG. 24 is a cross-sectional view of an eighth embodiment of the optical connection structure of the present invention. FIG. 25 is a cross-sectional view of a modified example of the eighth embodiment.

[First Embodiment]
The first embodiment of the optical connection structure of the present invention will be described with reference to FIGS. 1A and 2E. The dimensions of the members in each figure may be exaggerated in order to clearly grasp the structure.

As shown in FIGS. 1A to 2E, the optical connection structure 1 has, for example, a plate shape extending in one direction. Hereinafter, the direction in which the optical connection structure 1 extends is referred to as a longitudinal direction. The optical connection structure 1 includes a photoelectric composite transmission unit 2, an optical fiber member 3, and an adhesive member 4.

The photoelectric composite transmission unit 2 has a plate shape long in the longitudinal direction. The photoelectric composite transmission unit 2 includes an optical waveguide 5, an electric circuit board 6 as an example of a substrate, a photoelectric conversion unit 7, a printed wiring board 8 as an example of a substrate, and an electric connector 9.

As shown in FIGS. 1B and 2C, the optical waveguide 5 has a film shape extending in the longitudinal direction. The optical waveguide 5 has a substantially rectangular shape when viewed from the bottom. The optical waveguide 5 includes an underclad 11 as an example of the cladding, a core 12, and an overclad 13.

The underclad 11 has the same bottom view shape as the optical waveguide 5. The core 12 is arranged on the other side of the underclad 11 in the thickness direction. A plurality of cores 12 are provided corresponding to a plurality of fiber cores 33 described later. The plurality of cores 12 are arranged to face each other at intervals in the width direction. The width direction is orthogonal to the longitudinal direction and the thickness direction. After that, the width direction is the same as described above. The core 12 contacts a part of the other surface of the underclad 11 in the thickness direction and does not contact the rest. Each of the plurality of cores 12 extends in the longitudinal direction. One end surface in the longitudinal direction of the core 12 is flush with one end surface in the longitudinal direction of the underclad 11. A mirror 10 is formed in the middle of the core 12 in the longitudinal direction. The overclad 13 has the same bottom view shape as the underclad 11. The overclad 13 is arranged on the other surface of the underclad 11 in the thickness direction. The overclad 13 covers the core 12. Specifically, the overclad 13 contacts the other surface and side surface of the core 12 in the thickness direction and the rest of the other surface of the underclad 11 in the thickness direction. One end surface in the longitudinal direction of the overclad 13 is flush with one end surface in the longitudinal direction of the underclad 11 and the core 12. As a result, the one end surface 14 in the longitudinal direction of the optical waveguide 5 is single. Examples of the material of the underclad 11, the core 12, and the overclad 13 include a transparent resin. The refractive index of the core 12 is higher than the refractive index of the underclad 11 and the overclad 13.

The electric circuit board 6 is arranged on one side (an example of the main surface) in the thickness direction of the optical waveguide 5. That is, the electric circuit board 6 is adjacent to the optical waveguide 5 in the thickness direction. The electric circuit board 6 extends in the longitudinal direction. The electric circuit board 6 includes, for example, a flexible printed circuit board (FPC).

The longitudinal length of the electric circuit board 6 is the same as the longitudinal length of the optical waveguide 5. When projected in the thickness direction, the electric circuit board 6 overlaps the entire optical waveguide 5. Specifically, the one end surface and the other end surface in the longitudinal direction of the electric circuit board 6 are flush with the one end surface 14 and the other end surface in the longitudinal direction of the optical waveguide 5, respectively. The width of the electric circuit board 6 is, for example, the same as the width of the optical waveguide 5. The width is the length in the width direction. The electric circuit board 6 includes, for example, a support layer 25 and a conductor layer (not shown) arranged on one side of the support layer in the thickness direction. Examples of the material of the support layer 25 include a resin and a metal. The conductor layer comprises a series of terminals and wiring. The material of the conductor layer is a conductor.

The laminated body of the optical waveguide 5 and the electric circuit board 6 forms the optical-electric mixed board 44. That is, the optical / electric mixed mounting substrate 44 includes an optical waveguide 5 and an electric circuit board 6. The photoelectric mixed substrate 44 has flexibility. As shown in FIGS. 2C and 2D, the intermediate portion in the longitudinal direction of the photoelectric mixed mounting substrate 44 is curved to one side in the thickness direction.

The photoelectric conversion unit 7 is arranged on one side of the electric circuit board 6 in the thickness direction. Specifically, the photoelectric conversion unit 7 is electrically connected to a terminal (not shown) of the electric circuit board 6. Further, the photoelectric conversion unit 7 includes a light receiving / receiving element 17 that overlaps with the mirror 10 when projected in the thickness direction.

The light receiving / receiving element 17 includes a photodiode that converts an optical signal into an electric signal, and / or a laser diode that converts an electric signal into an optical signal. The photoelectric conversion unit 7 may further include an auxiliary element 18. The auxiliary element 18 includes, for example, a drive integrated circuit, an impedance conversion amplifier circuit, and a retimer integrated circuit. For example, the auxiliary elements 18 are arranged to face each other on the other side in the longitudinal direction of the light receiving / receiving element 17 at intervals.

As shown in FIGS. 2C and 2D, the printed wiring board 8 is arranged on one side of the electric circuit board 6 in the thickness direction. Therefore, in the optical connection structure 1, the optical waveguide 5, the electric circuit board 6, the photoelectric conversion unit 7, and the printed wiring board 8 are arranged in order toward one side in the thickness direction. The printed wiring board 8 is adjacent to the optical waveguide 5 in the thickness direction.

As shown in FIGS. 1A and 1B, the printed wiring board 8 has the same outer shape as the photoelectric composite transmission unit 2 in a plan view. The printed wiring board 8 has a substantially flat plate shape extending in the longitudinal direction. The length of the printed wiring board 8 is longer than the length of the electric circuit board 6. As shown in FIG. 2D, the longitudinal end surface of the printed wiring board 8 is arranged at the same position as the longitudinal end surface of the electric circuit board 6 when projected in the thickness direction. On the other hand, the other end surface in the longitudinal direction of the printed wiring board 8 is arranged on one side in the longitudinal direction with respect to the other end surface in the longitudinal direction of the electric circuit board 6. As shown in FIG. 1B, the width of the printed wiring board 8 is wider than the width of the electric circuit board 6. Specifically, as shown in FIG. 1A, the printed wiring board 8 has a shape in which the central portion in the width direction is cut out from one end surface in the longitudinal direction toward the other side in the longitudinal direction. That is, the printed wiring board 8 has a notch 19. In other words, the printed wiring board 8 has a substantially U-shaped (or U-shaped) shape in a plan view. The notch 19 has a substantially rectangular shape in a plan view. The area around the notch 19 of the printed wiring board 8 overlaps with the electric circuit board 6 when projected in the thickness direction. This region is referred to as an inner region 20. The printed wiring board 8 has an inner region 20 and an outer region 21. The outer region 21 is arranged outside the inner region 20. Specifically, the outer region 21 is arranged on both outer sides in the width direction and the other side in the longitudinal direction of the inner region 20. The outer region 21 does not overlap with the electric circuit board 6 when projected in the thickness direction. The printed wiring board 8 includes a substrate 26 and terminals (not shown).

As shown in FIGS. 2C and 2D, the other side of the printed wiring board 8 in the thickness direction comes into contact with one side of the optical / electric mixed circuit board 44. One side portion of the photoelectric mixed mounting substrate 44 is a portion arranged on one side in the longitudinal direction from the middle portion on one side in the thickness direction of the photoelectric mixed mounting substrate 44. In the first embodiment, the other side of the printed wiring board 8 in the thickness direction comes into contact with one side of the electric circuit board 6 in the thickness direction. On the other hand, the other side of the printed wiring board 8 in the thickness direction is separated from the other side of the one side of the electric circuit board 6 in the thickness direction in the thickness direction. The other side portion is a portion arranged on the other side of the middle portion in the longitudinal direction. That is, in the first embodiment, the other side portion of the optical / electric mixed mounting substrate 44 extends toward one side in the longitudinal direction while being spaced apart from the printed wiring board 8. The intermediate portion of the optical / electric mixed circuit board 44 approaches the printed wiring board 8 toward one side in the longitudinal direction. One side of the optical / electric mixed circuit board 44 extends toward one side in the longitudinal direction while being in contact with the printed wiring board 8.

The board 26 has the above-mentioned plan view shape of the printed wiring board 8. Examples of the material of the substrate 26 include a hard material. Examples of the hard material include glass fiber reinforced epoxy resin. The terminal (not shown) is provided on the other surface of the substrate 26 in the thickness direction.

As shown in FIGS. 2C and 2D, the electric connector 9 is arranged on the other side of the printed wiring board 8 in the thickness direction. As shown in FIG. 1B, the electric connector 9 has a substantially rectangular shape that is long in the width direction, for example, when viewed from the bottom. Further, as shown in FIGS. 2C and 2D, the electric connector 9 has a substantially U-shaped (or U-shaped) cross-sectional view. The electric connector 9 has an insertion port 23 and a connector terminal (not shown). The insertion port 23 is configured so that the other end portion of the optical / electric mixed mounting substrate 44 in the longitudinal direction can be inserted. Specifically, the insertion port 23 is open toward one side in the longitudinal direction. A connector terminal (not shown) is provided in the insertion port 23. The other end of the optical / electric mixed board 44 in the longitudinal direction is inserted into the insertion port 23, and the terminal of the electric circuit board 6 comes into contact with the connector terminal, whereby the electric connector 9 is electrically connected to the electric circuit board 6. Examples of the electric connector 9 include an FPC connector, a ZIF connector, and a board connector.

As shown in FIGS. 1A and 1B, the optical fiber member 3 is arranged to face each other on one side in the longitudinal direction of the photoelectric composite transmission unit 2. The optical fiber member 3 includes an optical fiber 31 and a holding member 32 as an example of a positioning member.

As shown in FIG. 2C, the optical fiber 31 extends in the longitudinal direction. The optical fiber 31 includes a fiber core 33, a fiber clad 34, and a fiber coating layer (not shown). As shown in FIG. 1B, a plurality of fiber cores 33 are arranged at intervals in the width direction. The other end surface in the longitudinal direction of the fiber core 33 is arranged to face the one end surface 14 in the longitudinal direction of the core 12 in the longitudinal direction.

As shown in FIG. 2C, the fiber clad 34 covers the peripheral surface of the fiber core 33. The other end surface in the longitudinal direction of the fiber clad 34 is flush with the other end surface in the longitudinal direction of the fiber core 33. The fiber clad 34 is branched into a plurality of pieces at the other end in the longitudinal direction. As shown in FIG. 2E, the plurality of branched fiber clads 34 have a substantially annular shape in cross section. The fiber coating layer (not shown) covers the peripheral surface of the unbranched fiber clad 34. That is, the fiber coating layer (not shown) exposes the peripheral surface of the branched fiber clad 34. Examples of the material of the fiber core 33 and the fiber clad 34 include plastic and resin. The fiber core 33 has a higher refractive index than the fiber clad 34.

In the optical fiber 31, a plurality of fiber cores 33 and a plurality of fiber clads 34 corresponding thereto are connected in the width direction via a resin on one side portion in the longitudinal direction from the holding member 32. That is, the above-mentioned portion has a ribbon shape (strip shape) in which a plurality of fiber cores 33 are arranged in parallel in the width direction. Alternatively, the plurality of fiber cores 33 may be independent of each other (separated) in the width direction without using a resin.

As shown in FIGS. 2C and 2D, the holding member 32 is arranged at the other end of the optical fiber 31 in the longitudinal direction. As shown in FIG. 2E, the holding member 32 includes a groove plate 35 and a lid plate 36.

The groove plate 35 has a substantially rectangular plate shape extending in the width direction. One surface of the groove plate 35 in the thickness direction has, for example, a V-shaped groove 27 and a flat portion 28.

The groove 27 is arranged in the middle of the width direction on one side of the groove plate 35 in the thickness direction. A plurality of grooves 27 are provided corresponding to the plurality of fiber cores 33 and the plurality of fiber clads 34. Each of the plurality of grooves 27 is along the longitudinal direction. The bottom surface 37 of the plurality of grooves 27 comes into contact with a part of the peripheral surface of the plurality of fiber clads 34. The holding member 32 positions the fiber core 33 with respect to the core 12 of the optical waveguide 5. That is, the fiber core 33 is centered with respect to the core 12.

The flat portions 28 are arranged at both ends in the width direction on one side in the thickness direction of the groove plate 35. Specifically, the flat portion 28 is arranged on both outer sides of the groove 27 in the width direction. The flat portion 28 is a flat surface along the width direction and the longitudinal direction.

The lid plate 36 is arranged on one side of the groove plate 35 in the thickness direction. The lid plate 36 has a substantially rectangular plate shape extending in the width direction. The other surface 38 of the lid plate 36 in the thickness direction is a flat surface. The intermediate portion in the width direction of the other surface 38 in the thickness direction of the lid plate 36 comes into contact with a part of the peripheral surface of the plurality of fiber clads 34.
The groove plate 35 and the lid plate 36 sandwich the fiber core 33 and the fiber clad 34 in the thickness direction. Both ends in the width direction of the other surface 38 in the thickness direction of the lid plate 36 are spaced apart from the flat portion 28 of the groove plate 35 in the thickness direction.

As shown in FIGS. 2C and 2D, the other end surface of the holding member 32 in the thickness direction and the other end surface of the optical fiber 31 (fiber core 33 and fiber clad 34) in the thickness direction are flush with each other. Examples of the material of the holding member 32 include glass. Examples of the glass include borosilicate glass. A configuration of the holding member 32 and a method of holding the holding member 32 with respect to the optical fiber 31 are described in Japanese Patent Application Laid-Open No. 2020-079862.

The other end surface in the longitudinal direction of the optical fiber 31 (fiber core 33 and fiber clad 34) is in contact with the one end surface 14 in the longitudinal direction of the optical waveguide 5. The other end surface in the longitudinal direction of the lid plate 36 is in contact with one end surface in the longitudinal direction of the electric circuit board 6 and one end surface in the longitudinal direction of the printed wiring board 8. The above-mentioned surfaces face each other with a boundary line L (virtual line) between the photoelectric composite transmission unit 2 and the optical fiber member 3 interposed therebetween.

The boundary line L extends in the width direction. Specifically, the boundary line L is a boundary between the optical waveguide 5, the electric circuit board 6, and the optical fiber member 3.

As shown in FIGS. 1A and 1B, one adhesive member 4 is provided in the optical connection structure 1. The adhesive member 4 is arranged along the boundary line L. The adhesive member 4 is in contact with one end in the longitudinal direction of the photoelectric composite transmission unit 2 and the other end in the longitudinal direction of the optical fiber member 3.

Specifically, as shown in FIGS. 1B and 2C, the adhesive member 4 is in contact with one end edge in the longitudinal direction and its vicinity on the other surface in the thickness direction of the optical waveguide 5. The adhesive member 4 is in contact with one end edge in the longitudinal direction and its vicinity on both side surfaces in the width direction of the optical waveguide 5.

The adhesive member 4 is in contact with one end edge in the longitudinal direction and its vicinity on one surface in the thickness direction of the electric circuit board 6. Further, the adhesive member 4 is in contact with one end edge in the longitudinal direction and its vicinity on both side surfaces in the width direction of the electric circuit board 6.

As shown in FIGS. 1A and 1B, the adhesive member 4 is in contact with one end edge in the longitudinal direction and its vicinity on the inner side surface in the width direction of the printed wiring board 8. Further, as shown in FIG. 2D, the adhesive member 4 is in contact with one end edge in the longitudinal direction and its vicinity on one surface in the thickness direction of the printed wiring board 8. Further, the adhesive member 4 is in contact with one end edge in the thickness direction and its vicinity on one end surface in the longitudinal direction of the printed wiring board 8.

As shown in FIGS. 1A and 2C to 2E, the adhesive member 4 is in contact with the other end edge in the longitudinal direction on one surface in the thickness direction of the lid plate 36 and its vicinity. As shown in FIGS. 1B and 2C to 2E, the adhesive member 4 is in contact with the other end edge in the longitudinal direction and its vicinity on the other surface in the thickness direction of the groove plate 35. Further, the adhesive member 4 is in contact with the other end edge in the longitudinal direction and its vicinity on both side surfaces in the width direction of the groove plate 35 and the lid plate 36. Further, as shown in FIG. 2E, the adhesive member 4 has a portion that does not come into contact with the peripheral surface of the fiber core 33 on the bottom surface 37 of the groove plate 35 and a peripheral surface of the fiber core 33 on the other surface 38 in the thickness direction of the lid plate 36. It is in contact with a part that does not contact. The adhesive member 4 is in contact with the flat portion 28 of the groove plate 35 and both ends of the lid plate 36 on the other surface 38 in the thickness direction.

Thereby, one adhesive member 4 adheres the optical waveguide 5, the electric circuit board 6, the printed wiring board 8, the optical fiber 31, and the holding member 32. Further, the holding member 32 is adhered to the optical waveguide 5, the electric circuit board 6, and the printed wiring board 8 by one adhesive member 4.

In order to manufacture this optical connection structure 1, first, each of the photoelectric composite transmission unit 2 and the optical fiber member 3 is prepared.

A photoelectric composite transmission unit 2 is manufactured by using an optical waveguide 5, an electric circuit board 6, a photoelectric conversion unit 7, and a printed wiring board 8 by a known method.

The fiber coating layer (not shown) at the other end of the optical fiber 31 in the longitudinal direction is peeled from the fiber clad 34, and then the fiber clad 34 is branched corresponding to the plurality of fiber cores 33, and then a plurality. The fiber clad 34 of the above is fitted into each of the plurality of grooves 27 of the groove plate 35. After that, the lid plate 36 is arranged on the plurality of fiber clads 34. As a result, the optical fiber member 3 is manufactured.

Next, the one end surface in the longitudinal direction of the photoelectric composite transmission unit 2 and the other end surface in the longitudinal direction of the optical fiber member 3 are brought into contact with each other (specifically, they are butted against each other). At this time, the core 12 and the fiber core 33 are aligned.

After that, the adhesive composition is placed along the boundary line L. The properties of the adhesive composition are liquid or semi-solid. The adhesive composition comprises, for example, a curable adhesive. Examples of the curable adhesive include a photocurable adhesive and a thermosetting adhesive. Examples of the adhesive composition include an epoxy adhesive composition and an acrylic adhesive composition.

After that, if the adhesive composition is a curable adhesive, the adhesive composition is cured. As a result, the adhesive member 4 is formed. As a result, the single adhesive member 4 adheres the optical waveguide 5, the electric circuit board 6, the printed wiring board 8, the optical fiber 31, and the holding member 32.

[Action and effect of the first embodiment]
In this optical connection structure 1, even if the adhesive member 4 shrinks due to curing, there is only one adhesive member 4, which is an optical waveguide 5, an optical fiber 31, an electric circuit board 6, and a printed wiring board 8. And glue. Therefore, it is possible to suppress the deformation of the optical fiber 31 due to the difference in the contracted state of the two adhesive members 4 as in Patent Document 1. Therefore, the optical connection reliability can be improved. Since there is only one adhesive member 4 in the optical connection structure 1, it is possible to suppress a decrease in adhesive strength.

As a result, the optical connection structure 1 suppresses the deformation of the optical fiber 31, improves the optical connection reliability, and has excellent adhesive strength.

Further, in this optical connection structure 1, the photoelectric composite transmission unit 2 includes a printed wiring board 8 as an example of a substrate. The printed wiring board 8 is rigid. Therefore, the optical connection reliability between the optical waveguide 5 and the optical fiber 31 can be further improved.

Further, in the optical connection structure 1, the photoelectric composite transmission unit 2 further includes an electric circuit board 6 as an example of the substrate. Since the optical waveguide 5 and the electric circuit board 6 capable of supporting one surface in the thickness direction thereof are bonded by one adhesive member 4, the strength is further improved.

Furthermore, the optical connection structure 1 further includes a holding member 32. Therefore, the optical waveguide 5 and the optical fiber 31 are surely aligned by the holding member 32. Therefore, the optical connection reliability can be improved.

[Modified example of the first embodiment]
In the following modification, the same members and processes as those in the first embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the modified example can exhibit the same effect as that of the first embodiment, except for special mention. Further, the first embodiment and its modifications can be combined as appropriate.

As shown in FIG. 3, the photoelectric composite transmission unit 2 and the optical fiber member 3 do not have to come into contact with each other. Specifically, the longitudinal end surface 14 of the optical waveguide 5 is spaced apart from the longitudinal end surface of the optical fiber 31. The one end surface in the longitudinal direction of the electric circuit board 6 is spaced apart from the other end surface in the longitudinal direction of the lid plate 36. The length of the above-mentioned interval in the longitudinal direction is, for example, 100 μm or less, preferably 75 μm or less, and more than 0 μm, for example, from the viewpoint of ensuring the optical connection reliability between the optical waveguide 5 and the optical fiber 31. It is preferably 10 μm or more.

The total light transmittance of the adhesive member 4 is, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and for example, 100% or less.

As shown in FIG. 4, in the optical connection structure 1 of the modified example of the first embodiment, the photoelectric conversion unit 7, the electric circuit board 6, the optical waveguide 5, and the printed wiring board 8 face one side in the thickness direction. Are arranged in order. That is, the arrangement of the optical waveguide 5 and the electric circuit board 6 on the optical / electric mixed board 44 is turned upside down. In this modification, the one end surface in the longitudinal direction of the electric circuit board 6 comes into contact with the other end surface in the longitudinal direction of the groove plate 35.

As shown in FIG. 5, in the holding member 32 of the modified example of the first embodiment, the flat portion 28 of the groove plate 35 and both ends in the width direction on the other surface 38 in the thickness direction of the lid plate 36 are in contact with each other. .. There is no adhesive member 4 between them. Therefore, the adhesive member 4 does not come into contact with the flat portion 28 of the groove plate 35 and both ends in the width direction on the other surface 38 in the thickness direction of the lid plate 36. In this modification, the lid plate 36 in contact with the groove plate 35 comes into contact with the printed wiring plate 8 (see FIG. 2D), so that the fiber core 33 and the core 12 are well aligned. On the other hand, in the first embodiment, as shown in FIG. 2E, since the adhesive member 4 exists between the flat portion 28 of the groove plate 35 and the other surface 38 in the thickness direction of the lid plate 36, the adhesive strength is excellent.

In the method for manufacturing the optical connection structure 1, the adhesive composition is arranged on either one or both of the one end surface in the longitudinal direction of the photoelectric composite transmission unit 2 and the other end surface in the longitudinal direction of the optical fiber member 3, and then the photoelectric composition is arranged. The composite transmission unit 2 and the optical fiber member 3 can also be bonded to each other.

[Second Embodiment]
In the following second embodiment, the same members and processes as those in the first embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the second embodiment can exhibit the same effects as those of the first embodiment, except for special mention. Further, the first embodiment, the second embodiment and their variations can be appropriately combined.

As shown in FIGS. 6A and 6B, the printed wiring board 8 has a through hole 39 penetrating the substrate 26 in the thickness direction. The through hole 39 is arranged substantially in the center of the printed wiring board 8 in a plan view. The through hole 39 has a substantially rectangular shape extending in the longitudinal direction. The inner region 20 of the printed wiring board 8 is arranged around the through hole 39.

As shown in FIG. 6A, the adhesive member 4 does not come into contact with the inner surface facing the through hole 39. As shown in FIG. 6B, the adhesive member 4 comes into contact with the printed wiring board 8 arranged on one side in the thickness direction of one end in the longitudinal direction of the optical waveguide 5. Specifically, the adhesive member 4 is in contact with one end edge in the longitudinal direction on one side in the thickness direction of the printed wiring board 8 described above, its vicinity, and one end surface in the longitudinal direction of the printed wiring board 8 described above.

In the second embodiment, the contact area between the printed wiring board 8 and the adhesive member 4 can be increased as compared with the first embodiment, as shown in FIGS. 2C and 6B. Therefore, the optical connection reliability between the optical waveguide 5 and the optical fiber 31 can be further improved.

[Modified example of the second embodiment]
In the following modification, the same members and processes as those in the second embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the modified example can exhibit the same effect as that of the second embodiment, except for special mention. Further, the second embodiment and its modifications can be combined as appropriate.

As shown in FIG. 7, in the optical connection structure 1 of the modified example of the second embodiment, the photoelectric conversion unit 7, the electric circuit board 6, the optical waveguide 5, and the printed wiring board 8 face one side in the thickness direction. Are arranged in order. That is, the arrangement of the optical waveguide 5 and the electric circuit board 6 on the optical / electric mixed board 44 is turned upside down. One end surface in the longitudinal direction of the electric circuit board 6 comes into contact with the other end surface in the longitudinal direction of the groove plate 35.

[Third Embodiment]
In the following third embodiment, the same members and processes as those in the first and second embodiments described above are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the third embodiment can exhibit the same effects as those of the first and second embodiments, except for special mention. Further, the first embodiment, the second embodiment, the third embodiment and their modified examples can be appropriately combined.

As shown in FIG. 8, the printed wiring board 8 may have a flat plate shape in a cross section passing through the core 12. That is, the printed wiring board 8 does not have to have the notch 19 and the through hole 39. In the cross section passing through the core 12, one side of the optical / electric mixed circuit board 44 in the longitudinal direction is in contact with the printed wiring board 8.

[Modified example of the third embodiment]
In the following modification, the same members and processes as those in the third embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the modified example can exhibit the same effect as that of the third embodiment, except for special mention. Further, the third embodiment and its modifications can be combined as appropriate.

As shown in FIG. 9, the photoelectric mixed mounting substrate 44 includes a protrusion 51. The protruding portion 51 projects from the printed wiring board 8 to one side in the longitudinal direction when projected in the thickness direction. The adhesive member 4 comes into contact with the protruding portion 51 of the opto-electrically mixed substrate 44 and the optical fiber member 3.

As shown in FIGS. 10 to 12, the adhesive member 4 may come into contact with one side of the printed wiring board 8 in the thickness direction.

As shown in FIG. 10, the printed wiring board 8 includes a second protrusion 52. When projected in the thickness direction, the second projecting portion 52 projects from the opto-electrically mixed substrate 44 to one side in the longitudinal direction. In this modification, the optical fiber member 3 does not include the holding member 32 and includes only the optical fiber 31. The entire longitudinal direction of the optical fiber 31 has, for example, a ribbon shape (strip shape) in which a plurality of fiber cores 33 are arranged in parallel in the width direction. Alternatively, in the optical fiber 31, the plurality of fiber cores 33 may be independent of each other (separated) in the width direction. The one end surface 14 in the longitudinal direction of the optical waveguide 5 and the other end surface in the longitudinal direction of the optical fiber 31 are adjacent to each other with a minute interval in the longitudinal direction. The adhesive member 4 comes into contact with one end surface 14 in the longitudinal direction of the opto-electric mixed mounting substrate 44, the other end portion in the longitudinal direction of the optical fiber member 3, and one surface in the thickness direction of the second protrusion 52.

As shown in FIGS. 11 and 12, the printed wiring board 8 includes a recess 53 or a pedestal 54.

As shown in FIG. 11, the recess 53 is formed by removing one surface in the thickness direction at one end in the longitudinal direction of the substrate 26 of the printed wiring board 8. One end surface 14 in the longitudinal direction of the optical / electric mixed substrate 44 faces the recess 53. The optical fiber member 3 is placed on one side of the recess 53 in the thickness direction. The adhesive member 4 includes a one end surface 14 in the longitudinal direction of the opto-electric mixed mounting substrate 44, a side surface of the recess 53, and one surface of the recess 53 in the thickness direction in which the optical fiber member 3 is not in contact with the holding member 32. Contact.

As shown in FIG. 12, the printed wiring board 8 further includes a pedestal 54. The pedestal 54 is arranged on the other side portion in the longitudinal direction on one side in the thickness direction of the printed wiring board 8. The pedestal 54 is provided integrally with or separately from the substrate 26. An optical fiber member 3 is arranged on one side of the printed wiring board 8 in the thickness direction of one side in the longitudinal direction. The pedestal 54 has a plate shape extending in the longitudinal direction. One end surface in the longitudinal direction of the pedestal 54 and one end surface in the longitudinal direction of the opto-electric mixed mounting substrate 44 are flush with each other. The adhesive member 4 comes into contact with one end surface in the longitudinal direction of the optical / electric mixed circuit board 44, one end surface in the longitudinal direction of the pedestal 54, the other end surface in the longitudinal direction of the optical fiber member 3, and one surface in the thickness direction of the printed wiring board 8. do.

As shown in FIGS. 13 to 17, the other side portion in the longitudinal direction of the optical / electric mixed circuit board 44 may come into contact with one side in the thickness direction of the printed wiring board 8. The terminals (not shown) of the printed wiring board 8 are arranged to face the electrodes of the optical / electric mixed circuit board 44 in the thickness direction.

As shown in FIG. 13, the longitudinal end surface 14 of the optical / electric mixed circuit board 44 is flush with the longitudinal end surface of the printed wiring board 8. The adhesive member 4 comes into contact with the longitudinal end surface 14 of the optical / electric mixed circuit board 44, the longitudinal end surface of the printed wiring board 8, and the longitudinal end surface of the optical fiber member 3.

As shown in FIG. 14, the opto-electric mixed mounting substrate 44 includes a protrusion 51. The protruding portion 51 has the same configuration as the protruding portion 51 shown in FIG.

In FIG. 15, the printed wiring board 8 includes a second protrusion 52. The second protruding portion 52 has the same configuration as the second protruding portion 52 shown in FIG.

As shown in FIGS. 16 and 17, the printed wiring board 8 includes a recess 53 or a pedestal 54. The recess 53 shown in FIG. 16 has the same configuration as the recess 53 shown in FIG. The pedestal 54 shown in FIG. 17 has the same configuration as the pedestal 54 shown in FIG.

[Fifth Embodiment]
In the following fifth embodiment, the same members and processes as those in the first and second embodiments described above are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the fifth embodiment can exhibit the same effects as those of the first and second embodiments, except for special mention. Further, the first to fifth embodiments and variations thereof can be appropriately combined.

As shown in FIG. 18, in the optical connection structure 1 of the fifth embodiment, the printed wiring board 8 overlaps the boundary line L when projected in the thickness direction. Specifically, the printed wiring board 8 straddles the boundary line L.

The printed wiring board 8 has an overlapping region 41 that overlaps with one end in the longitudinal direction of the electric circuit board 6, and a protruding region 42 that protrudes from the overlapping region 41 toward one side in the longitudinal direction. The projecting region 42 projects from the optical waveguide 5 and the electric circuit board 6 toward one side in the longitudinal direction. The protruding region 42 overlaps with the optical fiber 31 when projected in the thickness direction. The protruding region 42 is adjacent to the optical waveguide 5 in the longitudinal direction.

On the other hand, in the fifth embodiment, the optical fiber member 3 does not include the holding member 32 but includes only the optical fiber 31. The other end surface of the optical fiber 31 in the longitudinal direction comes into contact with one end surface of the optical waveguide 5 in the longitudinal direction.

In this fifth embodiment, the adhesive member 4 comes into contact with the optical waveguide 5, the electric circuit board 6, the printed wiring board 8, and the optical fiber 31. Specifically, the adhesive member 4 is in contact with one end edge in the longitudinal direction and its vicinity on the other surface in the thickness direction of the optical waveguide 5. The adhesive member 4 is in contact with one end edge in the longitudinal direction and its vicinity on both side surfaces in the width direction of the optical waveguide 5.

The adhesive member 4 is in contact with one end surface in the longitudinal direction of the electric circuit board 6. The adhesive member 4 is in contact with one end edge in the longitudinal direction and its vicinity on both side surfaces in the width direction (not drawn in FIG. 18) of the electric circuit board 6.

The adhesive member 4 contacts the other surface in the thickness direction and one end surface in the longitudinal direction in the protruding region 42 of the printed wiring board 8. Further, the adhesive member 4 is in contact with one end edge in the longitudinal direction and its vicinity on one surface in the thickness direction of the protruding region 42.

The adhesive member 4 is in contact with the other end edge in the longitudinal direction and its vicinity on the other surface in the thickness direction of the optical fiber 31. The adhesive member 4 is in contact with a region of the printed wiring board 8 facing the protruding region 42 and a region facing the space on one side in the longitudinal direction from the protruding region 42 on one side of the optical fiber 31 in the thickness direction.

Compare the first to fifth embodiments. In the fifth embodiment, the adhesive member 4 contacts the protruding region 42 of the printed wiring board 8, and the adhesive member 4 contacts the optical fiber 31. From that point of view, the fifth embodiment can improve the adhesive strength. On the other hand, in the first embodiment and the second embodiment, the optical fiber member 3 includes the holding member 32, and the holding member 32 can align the core 12 and the fiber core 33, so that the optical connection reliability can be obtained. Excellent for.

[Variation example of the fifth embodiment]
In the following modification, the same members and processes as in the above-mentioned fifth embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the modified example can exhibit the same effect as that of the fifth embodiment, except for special mention. Further, the fifth embodiment and its modifications can be combined as appropriate.

As shown in FIG. 19, in the modified example of the fifth embodiment, the optical fiber 31 does not come into contact with the optical waveguide 5, but comes into contact with the protruding region 42.

Specifically, the one end surface in the longitudinal direction of the optical waveguide 5 is separated from the other end surface in the longitudinal direction of the optical fiber 31. The adhesive member 4 is filled between the optical waveguide 5 and the optical fiber 31. Therefore, the adhesive member 4 comes into contact with the longitudinal end surface 14 of the optical waveguide 5 and the longitudinal end surface of the optical fiber 31.

The other side of the protruding region 42 in the thickness direction contacts the other side of the optical fiber 31 in the thickness direction.

Further, the electric circuit board 6 is spaced apart from the fiber clad 34 in the longitudinal direction. The adhesive member 4 is filled between them.

Both the modified example and the fifth embodiment are suitable from the viewpoint of connection strength.

[Sixth Embodiment]
In the following sixth embodiment, the same members and processes as those in the first to fifth embodiments described above are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the sixth embodiment can exhibit the same effects as those of the first to fifth embodiments, except for special mention. Further, the first to sixth embodiments and variations thereof can be appropriately combined.

As shown in FIG. 20, in the photoelectric composite transmission unit 2 of the sixth embodiment, the underclad 11 of the optical waveguide 5 has a clad protruding portion 43. The clad protrusion 43 is made of the same material as the underclad 11 (a portion other than the clad protrusion 43) described above. The clad protrusion 43 is a support plate extending in the longitudinal direction. The clad protrusion 43 is an example of a substrate.

The clad protrusion 43 does not overlap with the core 12 but overlaps with the optical fiber 31 when projected in the thickness direction. The clad projecting portion 43 projects from one end surface 14 in the longitudinal direction of the core 12 toward one side in the longitudinal direction. Therefore, the underclad 11 including the clad protruding portion 43 overlaps the boundary line L when projected in the thickness direction. Specifically, the underclad 11 straddles the boundary line L. The underclad 11 has a substantially L-shaped cross section. The other surface of the clad protrusion 43 in the thickness direction is spaced apart from the optical fiber 31 in the thickness direction. The adhesive member 4 is filled between them. The clad protrusion 43 is adjacent to the optical waveguide 5 in the longitudinal direction.

The adhesive member 4 contacts the other surface in the thickness direction and one end surface in the longitudinal direction of the clad protrusion 43. Further, the adhesive member 4 is in contact with one end edge in the longitudinal direction and its vicinity on one surface in the thickness direction of the clad protrusion 43.

The optical connection structure 1 of the sixth embodiment does not include, for example, a printed wiring board 8. That is, the photoelectric composite transmission unit 2 includes, for example, an optical / electric mixed circuit board 44 and a photoelectric conversion unit 7, and does not include a printed wiring board 8.

[Action and effect of the sixth embodiment]
In the optical connection structure 1 of the sixth embodiment, the optical waveguide 5 includes a clad protrusion 43 as an example of the substrate. Since the clad projecting portion 43 is made of the same material as the under clad 11, it can be easily formed.

Further, since the optical connection structure 1 does not include the printed wiring board 8, the configuration of the photoelectric composite transmission unit 2 is simple.

[Variation example of the sixth embodiment]
In the following modification, the same members and processes as those in the sixth embodiment will be designated by the same reference numerals, and detailed description thereof will be omitted. Further, the modified example can exhibit the same action and effect as those of the sixth embodiment, except for special mention. Further, the sixth embodiment and its modifications can be combined as appropriate.

As shown in FIG. 21, in the modified example of the sixth embodiment, the optical fiber 31 does not come into contact with the underclad 11 other than the clad protrusion 43, the core 12, and the overclad 13, while the optical fiber 31 has a clad protrusion. Contact with the portion 43.

Specifically, the one end surface in the longitudinal direction of the underclad 11 other than the clad protrusion 43, the core 12, and the overclad 13 is spaced apart from the other end surface in the longitudinal direction of the optical fiber 31. The adhesive member 4 is filled between them. Therefore, the adhesive member 4 comes into contact with the one end surface of the underclad 11 other than the clad protrusion 43, the core 12 and the overclad 13 in the longitudinal direction, and the other end surface of the optical fiber 31 in the longitudinal direction.

The other side of the clad protrusion 43 in the thickness direction comes into contact with the other side of the optical fiber 31 in the thickness direction.

Both the modified example and the sixth embodiment are suitable from the viewpoint of connection strength.

[7th Embodiment]
In the following seventh embodiment, the same members and processes as those in the first to sixth embodiments described above are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the seventh embodiment can exhibit the same effects as those of the first to sixth embodiments, except for special mention. Further, the first to seventh embodiments and variations thereof can be appropriately combined.

As shown in FIG. 22, the optical connection structure 1 of the seventh embodiment further includes a pedestal 45. The pedestal 45 is a member for aligning the fiber core 33 with respect to the core 12. The pedestal 45 is arranged on the other side of the electric circuit board 6 and the optical fiber 31 in the thickness direction at intervals. The pedestal 45 extends in the longitudinal direction. When projected in the thickness direction, the pedestal 45 overlaps the boundary line L. Specifically, the pedestal 45 straddles the boundary line L. The pedestal 45 has one side portion 46 and the other side portion 47 in order in the longitudinal direction.

The other side portion 47 is thicker than the one side portion 46. The other surface in the thickness direction of the other side portion 47 and the other surface in the thickness direction of the one side portion 46 are flush with each other. On the other hand, the one side in the thickness direction of the other side portion 47 is arranged on one side in the thickness direction with respect to the one side in the thickness direction of the one side portion 46. The other side portion 47 contacts and supports the other surface of the optical waveguide 5 in the thickness direction. The one-side portion 46 supports the other surface of the optical fiber 31 in the thickness direction via the adhesive member 4. That is, the adhesive member 4 comes into contact with the other surface of the optical fiber 31 in the thickness direction and the one surface of the one side portion 46 in the thickness direction. The pedestal 45 is adjacent to the optical waveguide 5.

Further, the adhesive member 4 comes into contact with one end surface in the longitudinal direction of the electric circuit board 6, one end in the longitudinal direction on one end surface in the thickness direction of the electric circuit board 6, and its vicinity. The above-mentioned adhesive member 4 is single.

[Action and effect of the seventh embodiment]
The optical connection structure 1 includes a pedestal 45 as an example of a substrate. Therefore, the pedestal 45 ensures that the core 12 and the fiber core 33 are aligned. Therefore, the optical connection reliability can be improved.

[Modified example of the seventh embodiment]
In the following modification, the same members and processes as those in the above-mentioned seventh embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the modified example can exhibit the same effect as that of the seventh embodiment, except for special mention. Further, the seventh embodiment and its modifications can be combined as appropriate.

As shown in FIG. 23, in the modified example of the seventh embodiment, the optical fiber 31 does not come into contact with the optical waveguide 5. On the other hand, the optical fiber 31 comes into contact with one side portion 46 of the pedestal 45.

The pedestal 45 has one side portion 46 and the other side portion 47, and further has a boundary portion 48. The other side portion 47 has the same thickness as the one side portion 46. The boundary portion 48 is arranged between the one-sided portion 46 and the other-sided portion 47. The boundary portion 48 faces between the optical fiber 31 and the optical waveguide 5. The boundary portion 48 is thinner than the one-sided portion 46 and the other-sided portion 47.

The one-sided portion 46, the other-sided portion 47, and the boundary portion 48 described above form a recess 49. The recess 49 is recessed from one side of the pedestal 45 in the thickness direction toward the other side in the thickness direction. The recess 49 is filled with the adhesive member 4.

Both the modified example and the seventh embodiment are suitable from the viewpoint of connection strength.

[Eighth Embodiment]
In the following eighth embodiment, the same members and processes as those in the first to seventh embodiments described above are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the eighth embodiment can exhibit the same effects as those of the first to seventh embodiments, except for special mention. Further, the first to eighth embodiments and variations thereof can be appropriately combined.

As shown in FIG. 24, the optical connection structure 1 of the eighth embodiment does not include the pedestal 45.

The photoelectric composite transmission unit 2 does not include the printed wiring board 8 and the clad protrusion 43. The photoelectric composite transmission unit 2 includes a photoelectric mixed mounting substrate 44 and a photoelectric conversion unit 7.

The optical fiber member 3 does not include the holding member 32, but includes only the optical fiber 31.

[Action and effect of the eighth embodiment]
In the eighth embodiment, the optical connection structure 1 does not have a pedestal 45, the photoelectric composite transmission unit 2 does not have a printed wiring board 8 and a clad protrusion 43, and the optical fiber member 3 has a holding member 32. Since it is not provided, the configuration of the optical connection structure 1 can be simplified.

[Variation example of the eighth embodiment]
In the following modification, the same members and processes as those in the eighth embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the modified example can exhibit the same effect as that of the first embodiment, except for special mention. Further, the eighth embodiment and its modifications can be combined as appropriate.

As shown in FIG. 25, the optical fiber member 3 further includes a holding member 32 as an example of the positioning member. The configuration of the holding member 32 is the same as that of the first embodiment.

The optical connection structure 1 of the modified example further includes a holding member 32. Therefore, the optical waveguide 5 and the optical fiber 31 are surely aligned by the holding member 32. Therefore, the optical connection structure 1 of the modified example can improve the optical connection reliability as compared with the eighth embodiment.

Although the above invention has been provided as an exemplary embodiment of the present invention, this is merely an example and should not be construed in a limited manner. Modifications of the invention that are apparent to those skilled in the art are included in the claims below.

The optical connection structure is used for the optical connection between the optical waveguide and the optical fiber.

1 Optical connection structure 4 Adhesive member 5 Optical waveguide 6 Electric circuit board 8 Printed wiring board 11 Underclad 12 Core 26 Board 31 Optical fiber 32 Holding member (example of positioning member)
43 Clad protrusion 42 Projection area 45 Pedestal

Claims

Optical waveguide and
An optical fiber optically connected to the optical waveguide,
The substrate adjacent to the optical waveguide and
An optical connection structure comprising one adhesive member for adhering the optical waveguide, the optical fiber, and the substrate.
The optical connection structure according to claim 1, wherein the substrate includes a printed wiring board.
The optical connection structure according to claim 1 or 2, wherein the substrate includes an electric circuit board arranged on the main surface of the optical waveguide.
The optical waveguide includes a core and a cladding covering the core.
The optical connection structure according to claim 1, wherein the substrate includes a support plate made of the same material as the clad.
The optical connection structure according to claim 1, wherein the substrate includes a pedestal.
Further provided with a positioning member for positioning the optical fiber,
The optical connection structure according to any one of claims 1 to 5, wherein the positioning member is adhered to the optical waveguide, the optical fiber, and the substrate by the one adhesive member.