Opto-electric hybrid board, connector kit, and producing method of connector kit

An opto-electric hybrid board is capable of being mounted on a connector having a bottom wall. The opto-electric hybrid board sequentially includes an optical waveguide and an electric circuit board toward one side in a thickness direction of these. The optical waveguide includes an under clad layer, a core layer disposed on a one-side surface of the tinder clad layer, and an over clad layer disposed on the one-side surface of the under clad layer so as to cover the core layer. The under clad layer is in contact with an other-side surface in the thickness direction of the electric circuit board. The one-side surface in the thickness direction of the electric circuit board is capable of being placed on the bottom wall.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a 35 U.S.C. 371 National Stage Entry of PCT/JP2018/013651, filed on Mar. 30, 2018, the contents of all of which are herein incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to an opto-electric hybrid board, a connector kit, and a producing method thereof, to be specific, to an opto-electric hybrid board, a connector kit including the opto-electric hybrid board, and a producing method of a connector kit.

BACKGROUND ART

Conventionally, an opto-electric hybrid board on which an electric wire and an optical waveguide are mixedly mounted has been known.

For example, an opto-electric hybrid board that includes an optical element-mounted board having an insulating board and an electric wire, and an optical circuit layer having a plurality of core portions and a clad layer covering them has been proposed (ref: for example, Patent Document 1).

In the opto-electric hybrid board of Patent Document 1, the optical circuit layer has a belt shape that is long in a front-rear direction, and the optical element-mounted board is laminated on a rear end portion of the optical circuit layer. Meanwhile, a PMT connector is provided in a front end portion of the optical circuit layer, and the optical circuit layer is optically connected to an optical fiber by using the PMT connector.

The PMT connector (first connector) is specified so as to have a PMT main body m a U-shape when viewed from the front having two pin holes (first pin holes) (ref: for example, Non-Patent Document 1). To mount the opto-electric hybrid board on the PMT connector, the front end portion of the opto-electric hybrid board is disposed on the PMT main body.

When the opto-electric hybrid board is mounted on the PMT connector, a first phantom line connecting the center in the thickness direction of the plurality of core portions matches a second phantom line connecting the two pin holes.

Thereafter, a guiding pin (not shown) is inserted into the pin hole, and the guiding pin is inserted into a second pin hole (not shown) held by another PMT connector (second connector) mounted with the optical fiber, so that the optical circuit layer can be optically connected to the optical fiber.

CITATION LIST

Patent Document

Patent Document 1: Japanese Unexamined Patent Publication No. 2011-170251 Non-Patent Document 1: Detail Specification for PMT Connector, JPCA-PE03-01-07S-2006 Japan Electronics Packaging and Circuits Association

SUMMARY OF THE INVENTION

Problem to be Solved by the Invention

As shown inFIG. 16, in an opto-electric hybrid board103, an optical element-mounted board115may be laminated on both the rear end portion and the front end portion of an optical circuit layer114in accordance with its purposes and uses.

In this case, as shown inFIG. 17A, it is tentatively considered that in the opto-electric hybrid board103, the optical circuit layer114is disposed at the lower side thereof, and the optical circuit layer114is placed on a bottom wall107of a PMT main body104. In this tentative plan, a tolerance at a position in a thickness direction of a first line L11from the bottom wall107can be reduced because the thickness of an over clad layer118is mainly included.

Thus, the tolerance at the position in the thickness direction of the first line L11from the bottom wall107is recently required to be furthermore reduced.

On the other hand, a thickness T of the over clad layer118is a thickness from the lower surface of a core portion121to the lower surface of the over clad layer118, and changes in accordance with the thickness of the core portion121, so that the thickness T of the over clad layer118easily varies. In this case, there is a disadvantage that the unevenness of the thickness T of the over clad layer118is included in the above-described tolerance, so that the tolerance cannot be sufficiently reduced.

The present invention provides a connector kit that is capable of reducing a tolerance at a position in a thickness direction of a core layer from a bottom wall provided in a connector, a method for producing a connector kit, and an opto-electric hybrid board provided in the connector kit.

Means for Solving the Problem

The present invention (1) includes an opto-electric hybrid board being capable of being mounted on a connector having a bottom wall and sequentially including an optical waveguide and an electric circuit board toward one side in a thickness direction of these, wherein the optical waveguide includes an under clad layer, a core layer disposed on a one-side surface of the under clad layer, and an over clad layer disposed on the one-side surface of the under clad layer so as to cover the core layer, the under clad layer is in contact with an other-side surface in the thickness direction of the electric circuit board; and the one-side surface in the thickness direction of the electric circuit board is capable of being placed on the bottom wall.

In the opto-electric hybrid board, the under clad layer in the optical waveguide is in contact with the other-side surface in the thickness direction of the electric circuit board. When the opto-electric hybrid board is mounted on the connector, the one-side surface in the thickness direction of the electric circuit board is in contact with the bottom wall. Thus, a tolerance at a position in the thickness direction of the core layer from the bottom wall includes the tolerance between the electric circuit board and the under clad layer that is in contact therewith, and does not include the tolerance (unevenness) of the thickness of the over clad layer. As a result, the tolerance at the position in the thickness direction of the core layer can be reduced. Accordingly, the opto-electric hybrid board has excellent optical connecting reliability.

The present invention (2) includes the opto-electric hybrid board described in (1), wherein an end edge of the electric circuit board is located at the inside with respect to the end edge of the optical waveguide.

In the opto-electric hybrid board, the end edge of the electric circuit board is located at the inside with respect to that of the optical waveguide, so that when an adhesive having flowability is excessively disposed between the electric circuit board and the bottom wall, the excessive adhesive can be released outwardly from the end edge of the electric circuit board to be accommodated at the outside of the end edge of the electric circuit board and at one side in the thickness direction of the end edge of the optical waveguide.

The present invention (3) includes the opto-electric hybrid board described in (1) or (2), wherein the electric circuit board has a central portion and an end portion, and a distance between the central portion and the bottom wall is shorter than the distance between the end portion and the bottom wall.

According to the connector kit, the central portion of the electric circuit board can be surely brought into close contact with the bottom wall compared to the end portion. Thus, the tolerance at the position in the thickness direction of the core layer from the bottom wall can be reduced.

The present invention (4) includes the opto-electric hybrid board described in any one of (1) to (3), wherein the other-side surface in the thickness direction of the optical waveguide has a groove.

When the connector has a protruding portion, the protruding portion of the connector fits the groove of the optical waveguide, so that the opto-electric hybrid board can be surely mounted on the connector.

The present invention (5) includes a connector kit including the opto-electric hybrid board described in any one of (1) to (4) and a connector mounted with the opto-electric hybrid board and having a bottom wall, wherein a one-side surface in a thickness direction of an electric circuit board in the opto-electric hybrid board is placed on the bottom wall.

In the connector kit, the under clad layer in the optical waveguide is in contact with the other-side surface in the thickness direction of the electric circuit board, and the one-side surface in the thickness direction of the electric circuit board is placed on the bottom wall. Thus, the tolerance at the position in the thickness direction of the core layer from the bottom wall includes the tolerance of the thickness between the electric circuit board and the wider clad layer that is in contact therewith, and does not include the tolerance (unevenness) of the thickness of the over clad layer. As a result, the tolerance at the position in the thickness direction of the core layer from the bottom wall can be reduced. Accordingly, the connector kit of the present invention has excellent optical connecting reliability.

The present invention (6) includes a connector kit including the opto-electric hybrid board described in (4), and a connector mounted with the opto-electric hybrid board and including a main body having a bottom wall and a lid disposed at the other side m a thickness direction of the bottom wall, wherein a one-side surface in the thickness direction of an electric circuit board in the opto-electric hybrid board is placed on the bottom wall, and the lid has a protruding portion that can fit a groove.

According to the connector kit, the protruding portion of the lid can fit the groove of the optical waveguide, and thus, the opto-electric hybrid board can be positioned with respect to the connector.

The present invention (7) includes a method for producing a connector kit including a first step of preparing the opto-electric hybrid board described in any one of (1) to (4), a second step of preparing a connector having a bottom wall, and a third step of mounting the opto-electric hybrid board on the connector so as to place a one-side surface in a thickness direction of an electric circuit board in the opto-electric hybrid board on the bottom wall.

In the method for producing a connector kit, when the third step is carried out, the under clad layer in the optical waveguide is in contact with the other-side surface in the thickness direction of the electric circuit board, and the one-side surface in the thickness direction of the electric circuit board is in contact with the bottom wall. Thus, the tolerance at the position in the thickness direction of the core layer disposed on the one-side surface of the under clad layer includes the tolerance of the thickness between the under clad layer and the electric circuit board, and does not include the tolerance (unevenness) of the thickness of the over clad layer. As a result, the tolerance at the position in the thickness direction of the core layer can be reduced. Accordingly, the producing method of the present invention can produce the connector kit having excellent optical connecting reliability.

Effect of the Invention

The opto-electric hybrid board of the present invention can reduce a tolerance at a position in a thickness direction of a core layer, and has excellent optical connecting reliability.

The connector kit of the present invention can reduce the tolerance at the position in the thickness direction of the core layer from a bottom wall, and has excellent optical connecting reliability.

According to the connector kit of the present invention, the opto-electric hybrid board can be positioned with respect to a connector.

The method for producing a connector kit of the present invention can produce the connector kit having excellent optical connecting reliability.

DESCRIPTION OF EMBODIMENTS

One Embodiment of Connector Kit

InFIGS. 4A and 4B, the up-down direction on the plane of the sheet is an up-down direction (one example of a thickness direction, a first direction), the lower side on the plane of the sheet is a lower side (one side in the thickness direction, one side in the first direction), and the upper side on the plane of the sheet is an upper side (the other side in the thickness direction, the other side in the first direction).

InFIGS. 4A and 4B, the right-left direction on the plane of the sheet is a right-left direction (width direction perpendicular to the thickness direction (first perpendicular direction), or a second direction perpendicular to the first direction).

InFIGS. 3A and 3B, the right-left direction on the plane of the sheet is a front-rear direction (longitudinal direction (second perpendicular direction), a third direction perpendicular to the first direction and the second direction), the right side on the plane of the sheet is a front side (one side in the longitudinal direction, one side in the third direction), and the left side on the plane of the sheet is a rear side (the other side in the longitudinal direction, the other side in the third direction).

To be specific, directions are in conformity with direction arrows described in each view.

The definition of the directions does not mean to limit the directions at the time of production and use of an opto-electric hybrid board and a connector kit.

One embodiment of a connector kit of the present invention is described with reference toFIG. 1A to 4B.

InFIG. 2A, an over clad layer18to be described later is omitted so as to clearly show the relative arrangement and shape of a core layer17in an optical waveguide14to be described later.

InFIG. 2B, a cover insulating layer54to be described later is omitted so as to clearly show the relative arrangement and shape of a conductive layer53and a metal support layer51in an electric circuit board15to be described later.

As shown inFIGS. 1A and 1B, a connector kit1is configured to be connected (joined) to a second connector kit22having an optical fiber23(phantom line) as one example of an external optical circuit. To be specific, the connector kit1includes a connector2and an opto-electric hybrid board3.

An example of the connector2includes a PMT connector conforming to the JPCA specification (Detail Specification for PMT Connector. JPCA-PE03-01-07S-2006. Japan Electronics Packaging and Circuits Association). The connector2has a generally square tubular shape slightly extending in the front-rear direction. In this manner, the connector2has a generally rectangular frame shape when viewed from the front. The connector2includes a main body4, a lid5, and a mounting assisting member6as separate bodies.

The main body4has a U-shape when viewed from the front having an opening upwardly. The main body4integrally includes a bottom wall7and two extending walls8.

The bottom wall7has a generally rectangular flat plate shape extending in the right-left direction. The bottom wall7includes a bottom surface77in the main body4. The bottom surface77is the upper surface of the bottom wall7, and is a flat surface along the right-left direction (plane direction).

The extending walls8have a shape extending from both end edges in the right-left direction of the bottom wall7upwardly. Each of the two extending walls8has a generally rectangular flat plate shape extending in the up-down direction.

Each of the two extending walls8has a reference hole85as one example of a reference portion. Each of the two reference holes85is a hole that is perforated from each of the front surfaces of the two extending walls8rearwardly. Both of the two reference holes85are located at a predetermined position in the thickness direction from the bottom surface77of the bottom wall7. The two reference holes85are overlapped with each other when projected in the right-left direction.

As referred toFIGS. 4A and 4B, the two reference holes85are a reference of optical connection of the core layer17to the optical fiber23(ref:FIG. 1B) to be described later. Each of the two reference holes85is located at a predetermined position in the thickness direction from the bottom surface77of the bottom wall7. To be specific, the two reference holes85are located at the position in the thickness direction that is set (fixed) in advance by a length from the lower surface in the front end portion of the opto-electric hybrid board3to the center in the thickness direction of a core portion21from the bottom surface77. The two reference holes85can form a second phantom line L2connecting the two reference holes85along the right-left direction.

As shown inFIG. 1B, the main body4has a main body cut-out portion9. The main body cut-out portion9is formed by cutting out the inner surface of the rear end portion of the main body4. To be more specific, the main body cut-out portion9is formed by continuously cutting out the upper surface of the rear end portion of the bottom wall7, and the inner surface from the lower end portions of the rear end portions to the central portions in the up-down direction of the two extending walls8.

The lid5has a generally rectangular flat plate shape extending in the right-left direction. A length in the front-rear direction of the lid5is substantially the same as that in the front-rear direction of the main body4. A length in the right-left direction of the lid5is substantially the same as a gap between the two extending walls8. The lid5has a lid cut-out portion10. The lid cut-out portion10is formed by cutting out the lower surface of the rear end portion of the lid5. The lid cut-out portion10, along with the main body cut-out portion9, configures a connector cut-out portion24. The connector cut-out portion24continuously has the lid cut-out portion10and the main body cut-out portion9.

The mounting assisting member6is disposed in the rear end portion of the connector2. The mounting assisting member6has a generally square tubular (square ring) shape that is long in the right-left direction and extends in the front-rear direction. To be specific, the mounting assisting member6has a size in which the front end portion thereof fits the connector cut-out portion24. The rear end portion of the mounting assisting member6protrudes from the main body cut-out portion9and the lid cut-out portion10rearwardly. The mounting assisting member6is, for example, referred to as a boot in the JPCA specification.

A material for the connector2is not particularly limited as long as it can be accurately formed into a shape of the main body4, the lid5, and the mounting assisting member6described above, and can accurately mount the opto-electric hybrid board3thereon. Examples of the material for the connector2include resins and metals. Preferably, a resin is used.

A size of the connector2is appropriately set in accordance with the size of the opto-electric hybrid board3to be mounted.

The opto-electric hybrid board3is mounted on the connector2. The opto-electric hybrid board3has a generally flat plate shape extending in the front-rear direction. To be more specific, the opto-electric hybrid board3has a generally T-shape when viewed from the top in which the rear end portion thereof has a wide width (long length in the right-left direction). The opto-electric hybrid board3integrally includes an optical element-mounted region11and an optical waveguide region12.

As shown inFIGS. 2A and 2B, the optical element-mounted region11is a region that is located in the rear end portion of the opto-electric hybrid board3. The optical element-mounted region11is a region on which an optical element13to be described later is mounted. The optical element-mounted region11has a generally rectangular shape when viewed from the top. The optical element-mounted region11has rigidity.

The optical waveguide region12is a region that is located at the front side of the opto-electric hybrid board3. To be specific, the optical waveguide region12has a shape extending from the central portion in the right-left direction of the front end edge of the optical element-mounted region11forwardly. The optical waveguide region12has a generally rectangular shape when viewed from the top having a narrow width (short length in the right-left direction) with respect to the optical element-mounted region11. A length in the front-rear direction of the optical waveguide region12is longer than that in the front-rear direction of the optical element-mounted region11. The optical waveguide region12has soft flexibility compared to the optical element-mounted region11.

As shown inFIGS. 3A and 4A, the opto-electric hybrid board3sequentially includes the optical waveguide14and the electric circuit board15downwardly. The opto-electric hybrid board3includes the optical waveguide14, and the electric circuit board15that is located below the optical waveguide14.

As shown inFIGS. 2A and 2B, the optical waveguide14has the same outer shape as that of the opto-electric hybrid board3when viewed from the top. The optical waveguide14has flexibility. The optical waveguide14is a strip-type optical waveguide. To be specific, as shown inFIGS. 3A and 4A, the optical waveguide14sequentially includes an under clad layer16, the core layer17, and the over clad layer18upwardly. To be more specific, the optical waveguide14includes the under clad layer16, the core layer17that is disposed on a first upper surface20as one example of a one-side surface of the under clad layer16, and the over clad layer18that is disposed on the first upper surface20of the under clad layer16so as to cover the under clad layer16. The optical waveguide14preferably consists of only the under clad layer16, the core layer17, and the over clad layer18.

As shown inFIG. 2A, the under clad layer16has the same outer shape as that of the optical waveguide14when viewed from the top. The under clad layer16has a generally sheet (flat plate) shape extending in the front-rear direction. The under clad layer16is disposed over both the optical element-mounted region11and the optical waveguide region12. As shown inFIGS. 3A and 4A, the under clad layer16continuously has a first lower surface19, the first upper surface20that is disposed above the first lower surface19at spaced intervals to face thereto, and a first connecting surface that connects the end edges of these.

The first lower surface19forms the lower-most surface of the optical waveguide14. The first lower surface19extends in the plane direction. The first lower surface19is in contact with the upper surface (one example of an other-side surface in the thickness direction) of the electric circuit board15to be described later.

The first upper surface20is a flat surface in parallel in the plane direction.

The first connecting surface includes two first side surfaces25(refFIG. 4A) that connect both end edges in the right-left direction of the first lower surface19to both end edges in the right-left direction of the first upper surface20, and one first front surface26(ref:FIG. 3A) that connects the front end edge of the first lower surface19to that of the first upper surface20. The first side surfaces25and the first front surface26are a flat surface along the thickness direction. The first side surfaces25are flat surfaces (left side surface and right side surface) extending along the front-rear direction. The first front surface26is a front end surface along the right-left direction.

As a material for the under clad layer16, for example, a resin having transparency and flexibility is used, preferably, a resin having insulating properties, transparency, and flexibility is used. To be specific, examples thereof include epoxy resin, polyamic acid resin, and polyimide resin.

The under clad layer16has a thickness of, for example, 2 μm or more, preferably 10 μm or more, and for example, 100 μm or less, preferably 40 μm or less. A thickness of the under clad layer16is a length from the lower-most portion of the first lower surface19to the first upper surface20.

The core layer17is in contact with the first upper surface20of the wider clad layer16. As shown inFIG. 2A, the core layer17has the plurality of (three) core portions21that are disposed at spaced intervals to each other in the right-left direction. The plurality of core portions21have a shape extending in the front-rear direction. The plurality of core portions21are disposed over both the optical element-mounted region11and the optical waveguide region12. As shown inFIG. 4A, each of the plurality of core portions21has a generally rectangular shape when viewed from the front. In this manner, each of the plurality of core portions21continuously has a second lower surface31, a second upper surface32that is disposed above the second lower surface31at spaced intervals to face thereto, and a second connecting surface that connects the end edges of these.

The second lower surface31is a flat surface extending in the front-rear direction. The second lower surface31is in contact with the first upper surface20of the under clad layer16. The entire plurality of second lower surfaces31corresponding to the plurality of core portions21are located at the same position when projected in the right-left direction.

The second upper surface32is a flat surface extending in the front-rear direction. The second upper surface32is in parallel with the second lower surface31. The entire plurality of second upper surfaces32corresponding to the plurality of core portions21are located at the same position when projected in the right-left direction.

As shown inFIGS. 3A and 4, the second connecting surface continuously has two second side surfaces33that connect both end edges in the right-left direction of the second lower surface31to both end edges in the right-left direction of the second upper surface32, a second front surface34that connects the front end edges of the two third side surfaces31, and a mirror surface35that connects the rear end edges of the two second side surfaces31.

The second side surfaces33, along with the second lower surface31and the second upper surface32, are flat surfaces (left side surface and right side surface) extending in the front-rear direction.

The second front surface34is a flat surface extending in the right-left direction. The second front surface34is formed so as to be flush with the first front surface26in the thickness direction. The second front surface34is continuous to the first front surface26. The entire lower end edges of the plurality of second front surfaces34corresponding to the plurality of core portions21are located at the same position when projected in the right-left direction. Also, the entire upper end edges of the plurality of second front surfaces34corresponding to the plurality of core portions21are located at the same position when projected in the right-left direction.

Thus, the center in the thickness direction of the plurality of second front surfaces34corresponding to the plurality of core portions21(intermediate point between the lower end edge and the upper end edge of the second front surface34) forms a first phantom line L1passing them.

The mirror surface35is a second rear surface in the core layer17, and is an inclined surface making an angle of 45 degrees with respect to the second lower surface31(phantom surface along the plane direction). The mirror surface35is also a light transmission direction conversion member (or optical path conversion member) that changes a transmission direction of light (light signal) entering from the optical element13from the up-down direction to the front-rear direction.

A refractive index of the under clad layer16of the core laser17is set high with respect to that of the under clad layer16.

As a material for the core layer17, a material that satisfies the above-described refractive index is selected. To be specific, a resin having a high refractive index, excellent insulating properties, excellent transparency, and excellent flexibility is selected. To be specific, a resin illustrated in the under clad layer16is selected.

A size of the core layer17is appropriately set in accordance with its uses and purposes of the opto-electric hybrid board3. To be specific, the size of the core layer17may change in accordance with the plurality of opto-electric hybrid boards3to be produced (each opto-electric hybrid board3or each batch of the opto-electric hybrid board3).

The core layer17has a thickness of, for example, 10 μm or more, preferably 30 μm or more, and for example, 2000 μm or less, preferably 70 m or less. The core portion21has a width of, for example, 10 μm or more, preferably 150 μm or more, and for example, 200 μm or less, preferably 100 μm or less. A gap between the core portions21that are next to each other is, for example, 10 μm or more, preferably 150 μm or more, and for example, 2000 μm or less, preferably 1500 μm or less.

The over clad layer18covers the under clad layer16. The over clad layer18has the same outer shape as that of the under clad layer16when viewed from the top. The over clad layer18has a generally sheet (flat plate) shape extending in the front-rear direction. The over clad layer18is located over both the optical element-mounted region11and the optical waveguide region12. As shown inFIG. 4A, the over clad layer18is in contact with a portion other than the portion in contact with the second lower surface31of the core layer17on the first upper surface20of the under clad layer16, and is also in contact with the second upper surface32and the second side surfaces33of the core layer17. In this manner, the over clad layer18covers (embeds) the core layer17. The over clad layer18continuously has a third lower surface41, a third upper surface42that is disposed above the third lower surface41at spaced intervals to face thereto, and a third connecting surface that connects the end edges of these.

The third lower surface41is in contact with a portion with which the second lower surface31of the core layer17is not in contact of the first upper surface20of the under clad layer16, and is also in contact with the second upper surface32and the second side surfaces33of the core layer17. The third lower surface41extends in the front-rear direction, and has a plurality of flat surfaces facing the first upper surface20, the second upper surface32, and the second side surface33. The plurality of flat surfaces are continuous to each other.

The third upper surface42forms the upper-most surface of the optical waveguide14. The third upper surface42is along the front-rear direction, and extends along the front-rear direction. The third upper surface42is in parallel with the first upper surface20.

As shown inFIGS. 3A and 4A, the third connecting surface continuously has two third side surfaces43(ref:FIG. 4A) that connect both end edges in the right-left direction of the third lower surface41to both end edges in the right-left direction of the third upper surface42and a third front surface44(ref:FIG. 3A) that connects the front end surfaces of the two third side surfaces43.

The third side surfaces43are flat surfaces (left side surface and right side surface) along the front-rear direction. The third side surfaces43are formed so as to be flush with the first side surfaces25of the under clad layer16in the thickness direction. The third side surfaces43are continuous to the first side surfaces25.

The third front surface44is a front end surface along the right-left direction. The third front surface44is formed so as to be flush with the second front surface34in the thickness direction. The third front surface44is continuous to the second front surface34.

Then, the third front surface44, the second front surface34, and the first front surface26form one optical connecting surface45extending in the thickness direction and the right-left direction. The optical connecting surface45is a flat surface having the first front surface26, the second front surface34, and the third front surface44. The optical connecting surface45preferably consists of only the first front surface26, the second front surface34, and the third front surface44.

A refractive index of the over clad layer18is set low with respect to that of the core layer17. Preferably, the refractive index of the over clad layer18is the same as that of the under clad layer16.

As a material for the over clad layer18, a material that satisfies the above-described refractive index is selected. To be specific, a resin having a low refractive index, excellent insulating properties, excellent transparency, and excellent flexibility is selected. To be specific, the same resin as that for the under clad layer16is selected.

The over clad layer18has a thickness T of, for example, 2 μm or more, preferably 5 μm or more, and for example, 50 μm or less, preferably 40 μm or less. The thickness T of the over clad layer18is a length from the second upper surface32of the core layer17to the third upper surface42of the over clad layer18. To be more specific, the thickness T of the over clad layer18is a length from the first upper surface20of the wider clad layer16to a portion located at the upper-most portion on the third upper surface42of the over clad layer18.

When the plurality of opto-electric hybrid boards3are produced in the plurality of batches or in a single sheet, the thickness T of the plurality of over clad layers18corresponding to the plurality of opto-electric hybrid boards3greatly varies even wider the same conditions of production formulations. To be specific, a standard deviation of the thickness T of the plurality of over clad layers18is, for example, 0.5 μm or more, furthermore 1.0 μm or more, furthermore 1.5 μm or more, and for example, 3.0 μm or less.

As shown inFIG. 3A, the electric circuit board15is disposed on the lower surface of the optical waveguide14. The electric circuit board15is disposed over both the optical element-mounted region11and the optical waveguide region12.

As shown inFIG. 2B, the electric circuit board15has a similar shape that is smaller than the optical waveguide14when viewed from the bottom. To be specific, the electric circuit board15has each of both end edges in the right-left direction disposed at the inside in the right-left direction (inside in the width direction) with respect to each of both end edges in the right-left direction of the optical waveguide14when viewed from the bottom. That is, the electric circuit board15in the optical waveguide region12has a narrow width (short length in the right-left direction) with respect to the optical waveguide14in the optical waveguide region12.

As shown inFIG. 3A, the electric circuit board15sequentially includes the metal support layer51, a base insulating layer52, the conductive layer53, and the cover insulating layer54downwardly in the thickness direction. To be specific, the electric circuit board15includes the metal support layer51, the base insulating layer52that is disposed below the metal support layer51, the conductive layer53that is disposed below the base insulating layer52, and the cover insulating layer54that is disposed below the base insulating layer52so as to cover a portion of the conductive layer53. The electric circuit board15preferably consists of only the metal support layer51, the base insulating layer52, the conductive layer53, and the cover insulating layer54.

The metal support layer51is a reinforcement layer that supports the conductive layer53.

As shown inFIG. 2B, the metal support layer51is provided in the optical element-mounted region11. To be more specific, the metal support layer51is not provided in the optical waveguide region12, and is provided only in the optical element-mounted region11. The metal support layer51has a generally rectangular flat plate shape extending in the right-left direction. The metal support layer51has a similar shape that is slightly smaller than the outer shape of the electric circuit board15in the optical element-mounted region11. The metal support layer51has a plurality of (three) opening portions55corresponding to the plurality of (three) core portions21. As shown inFIG. 3B, each of the plurality of opening portions55passes through the metal support layer51in the thickness direction. Each of the plurality of opening portions55has a generally circular shape (or elliptical shape) when viewed from the top. As shown inFIG. 3A, each of the plurality of opening portions55includes the mirror surface35when viewed from the top.

As shown inFIG. 3A, the metal support layer51continuously has a metal upper surface56, a metal lower surface57that is disposed below the metal upper surface56at spaced intervals to face thereto, and a metal connecting surface58that connects the end edges of these.

The metal upper surface56is a flat surface extending in the plane direction. The metal lower surface57is a flat surface in parallel with the metal upper surface56. The metal upper surface56and the metal connecting surface58are in contact with the first lower surface19of the under clad layer16. In this manner, the metal support layer51gets under (is embedded in) the under clad layer16.

Examples of a material for the metal support layer51include metals such as stainless steel, 42-alloy, aluminum, copper-beryllium, phosphor bronze, copper, silver, aluminum, nickel, chromium, titanium, tantalum, platinum, and gold. In view of reinforcing properties (mechanical strength), stainless steel is used.

The metal support layer51has a thickness of, for example, 3 μm or more, preferably 10 μm or more, and for example, 100 μm or less, preferably 50 μm or less. The thickness of the metal support layer51is preferably thinner than that of the under clad layer16.

The base insulating layer52, along with the metal support layer51, is a support layer (base layer) that supports the conductive layer53. The base insulating layer52is an insulating layer that insulates the conductive layer53from the metal support layer51.

The base insulating layer52is provided in both the optical element-mounted region11and the optical waveguide region12. The base insulating layer52has the same outer shape as that of the electric circuit board15when viewed from the bottom. That is, the base insulating layer52continuously has the outer shape of the electric circuit board15corresponding to the optical element-mounted region11, and that of the electric circuit board15corresponding to the optical waveguide region12. The base insulating layer52has a generally rectangular flat plate shape extending in the front-rear direction in the optical element-mounted region11and the optical waveguide region12.

As shown inFIGS. 3A and 4A, the base insulating layer52continuously has a base upper surface61, a base lower surface62that is disposed below the base upper surface61at spaced intervals to face thereto, and a base connecting surface that connects the end edges of these.

The base upper surface61is a flat surface along the plane direction. The base upper surface61is in contact with the metal upper surface56of the metal support layer51, and the first lower surface19of the under clad layer16.

The base lower surface62is in parallel with the base upper surface61. The base lower surface62is in contact with the conductive layer53and the cover insulating layer54to be described later.

The base connecting surface has a base front surface63that connects the front end edge of the base upper surface61to that of the base lower surface62, and two base side surfaces64that connect both end edges in the right-left direction of the base upper surface61to those in the right-left direction of the base lower surface62.

The base front surface63is flush with the optical connecting surface45of the optical waveguide14in the thickness direction, and is continuous to the optical connecting surface45.

A connecting surface48is formed from the base front surface63and the optical connecting surface45.

The two base side surfaces64are flat surfaces that are m parallel with each other. The two base side surfaces64are disposed at the inside with respect to the first side surface25and the third side surface43of the optical waveguide14when viewed from the bottom. That is, both end edges in the right-left direction of the base insulating layer52are located at the inside with respect to both end edges in the right-left direction of the optical waveguide14. Thus, the base side surfaces64expose both end portions of the first lower surface19of the optical waveguide14downwardly. In this manner, an exposed portion65is formed in the first lower surface19.

As a material for the base insulating layer52, for example, a resin having insulating properties is used, preferably, a resin having insulating properties and flexibility is used. Examples of a material for the base insulating layer52include resins such as polyimide resin, polyether nitrile resin, polyether sulfone resin, polyethylene terephthalate resin, polyethylene naphthalate resin, and polyvinyl chloride resin. Preferably, polyimide is used.

The base insulating layer52has a thickness of, for example, 2 μm or more, preferably 5 μm or more, and for example, 20 μm or less, preferably 15 μm or less. A width (length in the right-left direction) of the exposed portion65is, for example, 2 μm or more, preferably 5 μm or more, and for example, 2 mm or less, preferably 1 mm or less.

The conductive layer53is a signal layer that transmits electricity (electric signals) between an external circuit board (not shown) and the optical element13.

The conductive layer53is provided in the optical element-mounted region11. The conductive layer53is in contact with the base lower surface62of the base insulating layer52in the optical element-mounted region11. The conductive layer53has a pattern shape that continuously has an optical-side terminal71, a wire72continuous to the optical-side terminal71, and an external terminal76.

As shown inFIG. 2A, the optical-side terminals71are disposed in alignment at spaced intervals to each other in each of the front-rear direction and the right-left direction. The two (one pair of) optical-side terminals71are provided with respect to the plurality of core portions21. To be specific, a first terminal73, and a second terminal74that is disposed at the rear side thereof at spaced intervals to face thereto are provided with respect to each of the core portions21. The plurality of first terminals73are disposed in alignment at spaced intervals to each other in the right-left direction. The plurality of second terminals74are disposed in alignment at spaced intervals to each other in the right-left direction. The plurality of second terminals74are disposed at the rear side of the plurality of first terminals73with the opening portion55sandwiched therebetween. Each of the first terminals73and the second terminals74has a generally rectangular shape (square land shape) when viewed from the bottom.

The plurality of wires72are continuously provided with respect to each of the first terminals73and the second terminals74. The plurality of wires72extend in the front-rear direction, and are disposed in parallel at spaced intervals to each other in the right-left direction at the rear side of the first terminals73. Of the plurality of wires72, a portion continuous to the first terminal73extends in the right-left direction.

The external terminals76are provided at the rear side of the optical-side terminals71. The plurality of (six) external terminals76are disposed in alignment at spaced intervals to each other in the right-left direction. The rear end edges of the plurality of external terminals76are along the rear end edge of the opto-electric hybrid board3. Each of the plurality of external terminals76is continuous to each of the plurality of wires72. Each of the plurality of external terminals76has a generally rectangular shape (square land shape) that is long in the front-rear direction when viewed from the bottom.

As a material for the conductive layer53, for example, conductors such as copper, nickel, gold, and solder are used, preferably, copper is used.

As shown inFIG. 3A, the cover insulating layer54is provided so as to correspond to the conductive layer53, to be specific, is provided in the optical waveguide region12. The cover insulating layer54is in contact with the base lower surface62(excluding a portion with which the conductive layer53is in contact) of the base insulating layer52in the optical element-mounted region11. The cover insulating layer54has the same outer shape as that of the base insulating layer52in the optical element-mounted region11when viewed from the bottom.

The cover insulating layer54has a pattern shape that covers the wire72and exposes the optical-side terminal71and the external terminal76.

The cover insulating layer54continuously includes a cover upper surface91, a cover lower surface92that is disposed below the cover upper surface91at spaced intervals to face thereto, and a cover connecting surface93that connects the end edges of these.

An example of a material for the cover insulating layer54includes the resin illustrated in the base insulating layer52.

A thickness of the electric circuit board15is the total thickness of the metal support layer51, the base insulating layer52, and the cover insulating layer54(to be specific, a length in the thickness direction from the upper-most portion on the metal upper surface56of the metal support layer51to the lower-most portion on the cover lower surface92of the cover insulating layer54), and is, for example, 13 μm or more, preferably 20 μm or more, and for example, 110 μm or less, preferably 60 μm or less.

When the plurality of opto-electric hybrid boards3are produced in the plurality of batches or in a single sheet under the same formulation, the unevenness of the thickness of the plurality of electric circuit boards15corresponding to the plurality of opto-electric hybrid boards3is small. To be specific, a standard deviation of the thickness of the plurality of electric circuit boards15is, for example, 2.0 μm or less, preferably 1.0 μm or less, more preferably 0.5 μm or less, and for example, 01 μm or more.

Next, a method for producing the connector kit1is described.

To produce the connector kit1, first, as shown inFIG. 1B, the opto-electric hybrid board3is prepared (first step), and the connector2is prepared (second step).

To prepare the opto-electric hybrid board3(to carry out the first step), for example, as shown inFIG. 3A, first, the electric circuit board15and the optical waveguide14are sequentially formed.

To be specific, first, the metal support layer51is prepared in a flat plate shape (to be specific, as a metal plate without having the opening portion55).

Next, the base insulating layer52is formed on the metal lower surface57of the metal support layer51. To be specific, a photosensitive resin composition containing the above-described resin is applied to the metal lower surface57, and thereafter, the base insulating layer52is formed by a photolithography method to be then heated (cured) as needed. The base insulating layer52is formed to have a larger size than or the same size as the optical waveguide14to be formed (fabricated) later.

Next, the conductive layer53is formed on the base lower surface62of the base insulating layer52. To be specific, the conductive layer53is formed in a pattern having the optical-side terminal71and the wire72by an additive method or a subtractive method, preferably by an additive method.

Next, the cover insulating layer54is formed below the base insulating layer52so as to expose the optical-side terminal71and cover the wire72. To be specific, the photosensitive resin composition containing the above-described resin is applied to the base lower surface62of the base insulating layer52and the surface (exposed surface) of the conductive layer53, and thereafter, the base insulating layer52is formed by the photolithography method to be then heated (cured) as needed.

Thereafter, the metal support layer51is, for example, trimmed by etching or the like, thereby forming the opening portion55.

In this manner, the electric circuit board15is prepared (fabricated).

Thereafter, the optical waveguide14is fabricated at the upper side of the opto-electric hybrid board3. To be more specific, the optical waveguide14is fabricated on the base insulating layer52and the metal support layer51.

To be specific, the photosensitive resin composition containing the above-described resin is applied to the base upper surface61of the base insulating layer52, and the metal upper surface56and the metal connecting surface58of the metal support layer51, and thereafter, the under clad layer16is formed by the photolithography method.

Next, the photosensitive resin composition containing the above-described resin is applied to the first upper surface20of the under clad layer16, and thereafter, the core layer17is formed by the photolithography method.

Next, as referred toFIG. 4A, the photosensitive resin composition containing the above-described resin is applied to the first upper surface20of the under clad layer16, and the second upper surface32and the second side surface33of the core layer17, and thereafter, the over clad layer18is formed by the photolithography method.

Subsequently, as referred toFIG. 3A, the mirror surface35is formed by laser processing or cutting processing.

In this manner, the optical waveguide14is fabricated.

Thereafter, the base insulating layer52is formed into the above-described shape (preferably, shape that is smaller than the optical waveguide14) by trimming such as laser processing. In this manner, both end edges in the right-left direction of the first lower surface19of the base insulating layer52are defined as the exposed portion65.

In this manner, the opto-electric hybrid board3is prepared (fabricated).

The opto-electric hybrid board3is a component for fabricating the connector kit1, furthermore, is a component in which the electric circuit board15in the opto-electric hybrid board3can be placed with respect to the bottom wall7of the connector2, and does not include the optical element13and the connector2to be described later. To be specific, the opto-electric hybrid board3is an industrially available device whose component alone is circulated. To be more specific, the opto-electric hybrid board3can be circulated alone separated from the connector2. Or, the opto-electric hybrid board3can be also circulated in a set with the connector2. In this case, the opto-electric hybrid board3is in a state in which the connector kit1is not yet configured (produced), and in the above-described set, the connector2and the opto-electric hybrid board3are circulated in separate members (two members) (to be specific, sold in a set).

Next, the optical element13is mounted on the opto-electric hybrid board3. Along with this, an external circuit (not shown) is mounted on the external terminal76.

The optical element13is, for example, a light emitting element and a light receiving element, and has two terminals (not shown) and a light emitting port (not shown).

To mount the optical element13on the opto-electric hybrid board3, as shown by a bold phantom line ofFIG. 3Aand a bold phantom line ofFIG. 2B, the two terminals (not shown) of each of the three optical elements13are electrically connected to the two optical-side terminals71corresponding to each of the three core portions21, and the optical elements13are mounted on the optical element-mounted region11. The optical elements13are supported by the metal support layer51, the base insulating layer52, and the cover insulating layer54. The light emitting port (not shown) of the optical element13is included in the opening portion55, and is overlapped with the mirror surface35when viewed from the bottom.

As shown inFIG. 1B, separately, the connector2is prepared (second step is carried out). To prepare the connector2, each of the main body4, the lid5, and the mounting assisting member6is prepared.

Next, the opto-electric hybrid board3is mounted on the connector2(third step).

To mount the opto-electric hybrid board3on the connector2(to carry out the third step), first, the front end portion of the opto-electric hybrid board3(the opto-electric hybrid board3that is mounted with the optical element13and the external terminal76) is put (inserted) into the mounting assisting member6.

Next, the opto-electric hybrid board3is placed on the bottom wall7of the main body4in a state where the electric circuit board15faces downwardly and the optical waveguide14faces upwardly. To be specific, as shown mFIGS. 3A and 4A, in the optical waveguide region12, the lower surface of the electric circuit board15, that is, the base lower surface62of the base insulating layer52in the optical waveguide region12is brought into contact with the bottom surface77of the bottom wall7in a state where the base lower surface62of the base insulating layer52faces downwardly and the third upper surface42of the over clad layer18of the optical waveguide14faces upwardly. Along with this, the front end portion of the mounting assisting member6fits the main body cut-out portion9.

Then, as shown inFIGS. 4A and 4B, a second phantom line L2based on the two reference holes85in the connector2matches a first phantom line L1in the opto-electric hybrid board3.

Subsequently, the lid5is disposed between the upper end portions of the two extending walls S. and the lid cut-out portion10of the lid5fits the upper end portion of the mounting assisting member6.

In this manner, the opto-electric hybrid board3is mounted on the connector2. In this manner, the connector kit1is produced.

Next, the connection of the connector kit1to the second connector kit22is described.

As shown inFIGS. 1A and 3A, the second connector kit22includes a second connector27and the optical fiber23.

The second connector27substantially has the same structure as that of the connector2, and has two second reference holes (not shown).

The optical fiber23has a plurality of second core portions28that are disposed in parallel in the right-left direction corresponding to the core portions21of the optical waveguide14.

In the second connector kit22, a phantom line formed by the two second reference holes in the second connector27matches a phantom line passing the center in the thickness direction of the plurality of second core portions28in the optical fiber23.

First, the connector kit1, the second connector kit22, and two guiding pins29are prepared, and each of the rear portions and the front portions of the guiding pins29is inserted into the reference hole85of the connector kit1and a second reference hole (not shown) of the second connector kit22. Then, the connecting surface48is brought into contact with the rear surface (second contact surface) of the optical fiber23. In this manner, the second front surface34of the core portion21is brought into surface-contact with the rear surface49of the second core portion28. The core portion21is overlapped with the second core portion28when projected in the front-rear direction. The connector2and the second connector27are joined by a clamp (not shown) or the like.

In this manner, the optical waveguide14is optically connected to the optical fiber23.

As shown inFIG. 4B, in the connector kit1, the under clad layer16in the optical waveguide14is in contact with the base upper surface61of the base insulating layer52in the electric circuit board15, and the base lower surface62of the base insulating layer52in the electric circuit board15is placed on the bottom wall7.

Thus, a tolerance of the central position in the thickness direction of the core layer17disposed on the first upper surface20of the under clad layer16includes the tolerance of the thickness of the under clad layer16and the electric circuit board15, and does not include the tolerance (unevenness) of the thickness T of the over clad layer18.

As a result, the tolerance at the central position in the thickness direction of the core layer17can be reduced.

Accordingly, the connector kit1has excellent optical connecting reliability.

As shown inFIG. 17A, in Comparative Example 1 (ref. Patent Document 1), the third upper surface42of the over clad layer18is placed on the bottom surface77. Meanwhile, a shape and a size of the core layer17change in accordance with the plurality of opto-electric hybrid boards3to be produced. Then, the thickness T of the over clad layer18also changes. Then, the tolerance of the central position in the thickness direction of the core layer17increases, since it includes the above-described thickness T of the over clad layer18. As shown inFIG. 17B, the first phantom line L1deviates from (does not match) the second phantom line L2, and in such a case, when the second phantom line L2of the connector2matches a phantom line (not shown) of the second reference hole (not shown) of the second connector27, the first phantom line L1deviates from the phantom line (not shown) of the second core portion28. That is, the core portion21of the optical waveguide14deviates from the second core portion28of the optical fiber23. As a result, the connecting reliability with the optical fiber23is remarkably reduced.

Meanwhile, in one embodiment, as shown inFIG. 4A, for example, the tolerance of the central position in the thickness direction of the core layer17does not include the tolerance (unevenness) of the thickness T of the over clad layer18.

Thus, the tolerance at the central position in the thickness direction of the core layer17can be surely reduced.

Accordingly, the connector kit1has furthermore excellent optical connecting reliability.

The connector kit1can use the reference hole85of the extending wall8as a reference of the optical connection of the core layer17in the optical waveguide14to the second core portion28.

That is, when the first phantom line L1matches the second phantom line L2, and a phantom line (not shown) of the second core portion28matches a phantom line (not shown) of the second reference hole (not shown) of the second connector27, by matching the second phantom line L2of the connector2in the connector kit1and the phantom line (not shown) of the second reference hole (not shown) of the second connector27using the guiding pin29, the first phantom line L1can match the phantom line (not shown) of the second core portion28. That is, the positioning in the thickness direction of the core portion21in the connector kit1with the second core portion28in the second connector kit22can be surely and easily carried out.

Thus, the optical connection of the optical waveguide14to the optical fiber23can be surely achieved.

Modified Examples

In the following each of the modified examples, the same reference numerals are provided for members and steps corresponding to each of those m the above-described one embodiment, and their detailed description is omitted.

Each of the modified examples can be appropriately used in combination.

Furthermore, each of the modified examples can achieve the same function and effect as that of one embodiment unless otherwise specified.

First Modified Example

In one embodiment, as shown inFIGS. 4A and 4B, the base lower surface62of the base insulating layer52is in direct contact with the bottom surface77of the bottom wall7. Alternatively, the base lower surface62(lower surface of the electric circuit board15) may be placed with respect to the bottom wall7.

In the first modified example, for example, as shown inFIG. 5B, the base lower surface62adheres (is fixed) to the mounting assisting member6via an adhesive layer37.

The adhesive layer37is interposed between the base lower surface62and the bottom surface77.

To allow the base lower surface62to adhere to the mounting assisting member6via the adhesive layer37, as shown inFIG. 5A, first, an adhesive composition38is disposed on the bottom surface77of the bottom wall7.

The adhesive composition38is, for example, liquid, semi-solid, or solid. Preferably, in view of forming the thin adhesive layer37, the adhesive composition38is liquid or semi-solid. That is, the adhesive composition38preferably has flowability Examples of the adhesive composition38include curable type and pressure-sensitive adhesive type. Preferably, in view of obtaining high adhesive properties, a curable type is used.

When the adhesive composition38is liquid or semi-solid, the adhesive composition38can be applied to the base lower surface62.

Next, the bottom surface77of the bottom wall7is brought into contact with the adhesive composition38(the adhesive layer37in the case of solid). In this manner, the adhesive composition38is sandwiched (pinched) between the bottom surface77and the base lower surface62in the thickness direction.

Thereafter, when the adhesive composition38is the curable type, the adhesive composition38is cured by heating, active energy ray application, moisture, or the like, thereby forming the adhesive layer37.

As shown inFIG. 5B, the base lower surface62of the base insulating layer52is fixed to the bottom wall7by the adhesive layer37.

When the adhesive composition38has flowability, the adhesive composition38tends to be released (flow) outwardly in a case of being sandwiched (pinched) between the bottom surface77and the base lower surface62in the thickness direction. In the opto-electric hybrid board3, however, both end edges in the right-left direction of the base insulating layer52are located at the inside with respect to both end edges in the right-left direction of the optical waveguide14, so that the adhesive composition38can be released outwardly from both end edges in the right-left direction of the base insulating layer52to be accommodated at the outside of both end edges in the right-left direction of the base insulating layer52and at the lower side of both end edges in the right-left direction of the optical waveguide14.

Second Modified Example and Third Modified Example

As shown inFIG. 6A, in the second modified example, in the optical waveguide region12, the electric circuit board15has the same width as that of the optical waveguide14. To be more specific, in the optical waveguide region12, each of both end edges in the right-left direction of the electric circuit board15is located at the same position as that of each of both end edges in the right-left direction of the optical waveguide14when viewed from the bottom.

As shown inFIG. 6B, in the third modified example, in the optical waveguide region12, the electric circuit board15has a wide width with respect to the optical waveguide14. To be more specific, in the optical waveguide region12, each of both end edges in the right-left direction of the electric circuit board15is located at the outside with respect to each of both end edges in the right-left direction of the optical waveguide14when viewed from the bottom.

The first modified example is, however, more preferable than the second modified example and the third modified example. In the case of the use of the adhesive composition38having flowability, as referred toFIG. 6A, in the second modified example, the adhesive composition38may crawl upwardly along both side surfaces (the base insulating layer52, the first side surface25, and the third side surface43) in the right-left direction of the opto-electric hybrid board3, so that the thickness of the adhesive layer37may not be stabilized. As referred toFIG. 6B, in the third modified example, when the adhesive composition38crawls up to both end portions in the right-left direction of the electric circuit board15, the electric circuit board15may be bent, so that the position in the right-left direction may deviate, or the position in the right-left direction may deviate due to a difference in thickness of the adhesive composition38on the right and left sides of the electric circuit board15. Furthermore, as referred toFIGS. 6A and 6B, in the second modified example and the third modified example, when the width of the electric circuit board15is the same length as a gap between the two extending walls8, a void may be generated by the excessive adhesive composition38that loses an escape space.

As shown inFIGS. 5A and 5B, however, in the first modified example, when the width of the optical waveguide14is the same length as the gap between the two extending walls8, the width of the electric circuit board15is narrower than the optical waveguide14, so that in a case where the base lower surface62is placed on the bottom surface77, the excessive adhesive composition38that is sandwiched therebetween can be released to be accommodated at the outside of the end edge of the base insulating layer52and at the lower side of the end edge of the optical waveguide14. Thus, in the first modified example, the thickness of the adhesive composition38can be stabilized, and the tolerance at the central position in the thickness direction of the core layer17from the bottom wall7can be reduced.

Fourth Modified Example and Fifth Modified Example

In one embodiment, as shown inFIG. 4A, the base lower surface62is a flat surface. To be more specific, a distance between the central portion of the base lower surface62and the bottom surface77is the same as that between both end portions in the right-left direction of the base lower surface62and the bottom surface77.

Meanwhile, as shown inFIGS. 7A and 7B, in the fourth modified example and the fifth modified example, the central portion of the base lower surface62warps either upwardly or downwardly, and the distance between the central portion of the base lower surface62and the bottom surface77is different from that between both end portions in the right-left direction of the base lower surface62and the bottom surface77.

In the fourth modified example, as shown inFIG. 7A, the distance between the central portion of the base lower surface62and the bottom surface77is shorter than that between both end portions in the right-left direction of the base lower surface62and the bottom surface77. To be specific, the opto-electric hybrid board3has a generally circular arc (arch) shape when viewed from the cross section in which the central portion in the right-left direction thereof is located at the lower side with respect to both end portions in the right-left direction thereof. To be more specific, the opto-electric hybrid board3sags (warps) so as to go upwardly from the central portion in the right-left direction toward both end portions in the right-left direction.

Meanwhile, in the fifth modified example, as shown inFIG. 7B, the distance between the central portion of the base lower surface62and the bottom surface77is longer than that between both end portions in the right-left direction of the base lower surface62and the bottom surface77. To be specific, the opto-electric hybrid board3has a generally circular arc (arch) shape when viewed from the cross section in which the central portion in the right-left direction thereof is located at the upper side with respect to both end portions in the right-left direction thereof. To be more specific, the opto-electric hybrid board3sags (warps) so as to go downwardly from the central portion in the right-left direction toward both end portions m the right-left direction.

Of the fourth modified example and the fifth modified example, preferably, a fourth modified example is used.

In the fifth modified example, as shown inFIG. 7B, in a case where the adhesive composition38having flowability is disposed between the base lower surface62and the bottom surface77of the bottom wall7, when the base lower surface62is brought into close contact with the bottom wall7, both end portions in the right-left direction of the base lower surface62easily catches (bites) air (foam, void)39. Then, the air39continues to stay at the lower side of the electric circuit board15. Then, the position of the first phantom line L1in the opto-electric hybrid board3increases due to the air39, and thus, the first phantom line L may not match the second phantom line L2based on the two reference holes85.

Meanwhile, in the fourth modified example, when the adhesive composition38having flowability is disposed between the base lower surface62and the bottom surface77of the bottom wall7, the adhesive composition38can be released from the central portion in the right-left direction outwardly in the right-left direction. Furthermore, the central portion in the right-left direction of the base lower surface62can be brought into close contact with the bottom surface77to be surely contact therewith compared to both end portions in the right-left direction of the base lower surface62. Thus, the base lower surface62can surely adhere to the bottom surface77, and the possibility generated in the fourth modified example can be removed.

Although not shown, the opto-electric hybrid board3can also have a generally circular arc (arch) shape when viewed from the cross section in which the central portion in the front-rear direction of the base lower surface62warps either downwardly or upwardly.

Sixth Modified Example

In the sixth modified example, as shown inFIG. 8B, the third upper surface42of the over clad layer IS has grooves66that are dented downwardly. The plurality of (two) grooves66are provided between the core portions21that are next to each other along the core portions21when viewed from the top. The plurality of grooves66are disposed at spaced intervals to each other in the right-left direction.

As shown inFIG. 8A, the lid5has a plurality of lid protruding portions67as one example of protruding portions that can it the plurality of grooves66on the lower surface thereof. The plurality of lid protruding portions67have a rail shape.

In the connector kit1, the lid5is disposed with respect to the over clad layer18so that the lid protruding portions67fit (key-fit) the grooves66when the lid5is disposed.

In this manner, the position in the right-left direction of the core portion21in the connector2can be positioned.

Although not shown, the same fitting as the description above is also tentatively considered to be carried out by providing a third groove in the lower surface (to be specific, the base lower surface62of the base insulating layer52) of the electric circuit board15, and providing a bottom protruding portion in the bottom surface77of the bottom wall7. When the adhesive composition38is sandwiched between the lower surface of the electric circuit board15and the bottom surface77, however, the adhesive composition38greatly flows by the above-described fitting. To be specific, the adhesive composition38overflows from the third groove. Thus, there may be a case where the tolerance in the thickness direction of the core layer17cannot be reduced.

In the sixth modified example, however, as described above, the upper surface of the optical waveguide14, to be specific, the second upper surface32of the over clad layer18has the groove66. Thus, an increase in the tolerance in the thickness direction of the core layer17caused by the above-described adhesive composition38can be prevented.

Seventh Modified Example

In the sixth modified example, the entire grooves66are along the core portion21.

Meanwhile, in the seventh modified example, as shown inFIG. 9B, for example, a portion of the grooves66crosses (to be specific, is perpendicular to) the core portion21.

The groove66continuously has first grooves68and a second groove69.

The plurality of (two) first grooves68are provided between the core portions21that are next to each other along the core portions21.

The second groove69connects the first grooves68that are next to each other. The second groove69is perpendicular to the core portions21when viewed from the top. A depth of the second groove69is adjusted (cut out) to have a depth that does not expose the core layer17(or depth that is not in contact with the core layer17) in the over clad layer18.

As shown inFIG. 9A, the lid protruding portion67of the lid5has a shape corresponding to the first groove68and the second groove69.

The lid protruding portion67fits the groove66, so that both the position in the right-left direction and the position in the front-rear direction of the core portion21in the connector2can be positioned.

Eighth Modified Example to Thirteenth Modified Example

In one embodiment, as shown inFIGS. 3A and 4A, in the optical waveguide region12, the electric circuit board15includes the base insulating layer52. However, a layer structure of the electric circuit board15in the core portion21is not limited to this, and to be specific, in the eighth modified example to the thirteenth modified example, a layer structure is disclosed with reference toFIGS. 10 to 15.

Eighth Modified Example

As shown inFIG. 10, in the eighth modified example, in the optical waveguide region12, the electric circuit board15includes the base insulating layer52and the cover insulating layer54.

The cover lower surface92of the cover insulating layer54is in contact with the bottom surface77of the bottom wall7.

Ninth Modified Example

As shown inFIG. 11, in the ninth modified example, in the optical waveguide region12, the electric circuit board15includes the base insulating layer52, the conductive layer53(the wire72), and the cover insulating layer54.

The cover lower surface92of the cover insulating layer54is in contact with the bottom surface77of the bottom wall7.

Tenth Modified Example

As shown inFIG. 12, in the tenth modified example, in the optical waveguide region12, the electric circuit board15includes the metal support layer51and the base insulating layer52.

The metal upper surface56and the metal connecting surface58of the metal support layer51are in contact with the first lower surface19of the under clad layer16.

The base lower surface62of the cover insulating layer54is in contact with the bottom surface77of the bottom wall7.

Eleventh Modified Example

As shown inFIG. 13, in the eleventh modified example, in the optical waveguide region12, the electric circuit board15includes the metal support layer51, the base insulating layer52, and the cover insulating layer54.

The metal upper surface56and the metal connecting surface58of the metal support layer51are in contact with the first lower surface19of the under clad layer16in the optical waveguide14.

The cover lower surface92of the cover insulating layer54is in contact with the bottom surface77of the bottom wall7.

Twelfth Modified Example

As shown inFIG. 14, in the twelfth modified example, in the optical waveguide region12, the electric circuit board15includes the metal support layer51.

The metal upper surface56and the metal connecting surface58of the metal support layer51are in contact with the first lower surface19of the under clad layer16.

The metal lower surface57of the metal support layer51is in contact with the bottom surface77of the bottom wall7.

Thirteenth Modified Example

As shown inFIG. 15, in the optical waveguide region12, the electric circuit board15includes the metal support layer51, the base insulating layer52, the conductive layer53(the wire72), and the cover insulating layer54.

The metal upper surface56and the metal connecting surface58of the metal support layer51are in contact with the first lower surface19of the under clad layer16.

The cover lower surface92of the cover insulating layer54is in contact with the bottom surface77of the bottom wall7.

Other Modified Examples

A timing for mounting of the optical element13on the opto-electric hybrid board3is not particularly limited. For example, first, the opto-electric hybrid board3is mounted on the connector2, and the connector kit1is produced. Thereafter, the optical element13can be also mounted on the opto-electric hybrid board3in the connector kit1.

In one embodiment, as shown inFIG. 4A, the base front surface63is continuous to the optical connecting surface45. That is, the front end edge of the base insulating layer52is located at the same position as the front end edge of the optical waveguide14when projected in the thickness direction.

As referred toFIG. 3A, however, the front end edge of the electric circuit board15can be, for example, also disposed to deviate rearwardly or forwardly, preferably rearwardly with respect to the front end edge of the optical waveguide14. In this case, a range of deviation of the front end edge of the electric circuit board15is within a range in which the base lower surface62faces the bottom wall7.

In this case, the connecting surface48does not include the base front surface63, and includes only the optical connecting surface45(the third front surface44, the second front surface34, and the first front surface26).

In one embodiment, the optical waveguide14is fabricated on the electric circuit board15. However, the method for producing the opto-electric hybrid board3(first step) is not limited to this. For example, first, the under clad layer16, the core layer17, and the over clad layer18are formed, and the optical waveguide14is produced. Then, the optical waveguide14can be also attached onto (laminated on, adheres to) the electric circuit board15via, for example, an adhesive or the like.

In the optical waveguide14, the mirror surface35may be also a light transmission direction conversion member (or optical path conversion member) that changes the transmission direction of light transmitted in the plurality of core portions21from the front-rear direction to the up-down direction.

Although not shown, the third upper surface42of the over clad layer18may also have an uneven surface.

INDUSTRIAL APPLICATION

The opto-electric hybrid board of the present invention is provided in a connector kit.

DESCRIPTION OF REFERENCE NUMBER

1Connector kit2Connector5Lid7Bottom wall8Extending wall14Optical waveguide15Electric circuit board16Under clad layer17Core layer18Over clad layer20First upper surface (one example of one-side surface)23Optical fiber61Base upper surface (one example of other-side surface in thickness direction of electric circuit board)62Base lower surface (one example of other-side surface in thickness direction of electric circuit board)66Groove67Lid protruding portion68First groove69Second groove85Reference hole