JP2012083488A - Opto-electric composite substrate, circuit substrate, and opto-electric composite device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an opto-electric composite substrate for achieving both of ease of mounting and repair of an optical element and reduction in optical coupling loss of optical element and an optical waveguide.SOLUTION: An opto-electric composite substrate 10 comprises: an optical element mounting substrate 20 including an optical element mounting area 22 on which an optical element 110 is mounted; an electric circuit substrate 30 including an opening 32 larger than the optical element mounting substrate 20; and an optical circuit substrate 40 including an optical waveguide 42 provided with an optical path switching section 44. In the opto-electric composite substrate 10, the optical circuit substrate 40 and the electric circuit substrate 30 are stacked so that the optical path switching section 44 is arranged at a position facing the opening 32, and the optical path switching section 44 and the optical element mounting area 22 are arranged while facing each other by fitting the optical element mounting substrate 20 into the opening 32.

Description

  The present invention relates to an opto-electric composite substrate for mounting both an optical element and an electric element, a circuit board used therefor, and an opto-electric composite device on which the optical element and the electric element are mounted.

  With regard to this type of technology, Patent Document 1 discloses that an electrical circuit board with an optical waveguide is bonded to an optical circuit board on which an optical waveguide is formed and an electrical wiring board on which an electrical element is mounted with a sheet-like adhesive. A manufacturing method of the photoelectric composite substrate to be manufactured is described. Further, in Patent Document 2, an optical circuit board on which an optical waveguide is formed and an electric circuit board are joined, and an upper portion of the optical path conversion mirror is opened and filled with a light-transmitting resin, and the optical element is converted into an optical path conversion mirror. And positioning in an optically connected state and solder mounting on the optical circuit board.

  As described above, in the conventional photoelectric composite substrate, the optical circuit board and the electrical circuit board are joined, and the position of the optical waveguide is confirmed through the opening of the electrical circuit board. The optical element is mounted in alignment with the light receiving portion of the element.

  However, in the case of an opto-electric composite substrate (hereinafter sometimes abbreviated as a substrate) on which a large number of optical elements and electrical elements are mounted, such as a mother board of a large computer system, for example, the entire board every time an element fails It is difficult to remove and renovate the housing. In addition, since a large number of optical elements and electric elements are mounted, it takes a long time to perform the mounting operation.

  On the other hand, Patent Document 3 describes that an optical communication module in which an optical element and its drive circuit and amplifier circuit are mounted on a common substrate is solder-mounted so as to cover the opening of the electric circuit substrate. Yes. This optical communication module transmits and receives light to and from an optical waveguide formed on an optical circuit board below the electric circuit board. By mounting the optical element and the electric element on a common substrate in this way to make a module, the mounting and repairing work of the optical element is facilitated.

JP 2009-58923 A JP 2008-216712 A JP 2009-283712 A

  However, when a module substrate on which an optical element is mounted (hereinafter referred to as an optical element mounting substrate) is solder-mounted on an electric circuit board as in Patent Document 3, the mounting and repair work of the optical element is made more efficient. The problem is that the distance in the thickness direction from the optical waveguide is increased. This is because the optical path length between the light receiving and emitting part of the optical element and the optical waveguide (optical path conversion mirror) is increased by the thickness dimension of the optical element mounting substrate and the solder mounting portion, and the optical coupling loss is increased.

  The present invention has been made in view of the above-described problems, and is an optical device that can realize both the mounting and repair work of an optical element and the reduction of optical coupling loss between the optical element and the optical waveguide. The present invention provides an electric composite substrate and a photoelectric composite device, and a circuit board used for the photoelectric composite substrate.

  The optoelectric composite substrate of the present invention is provided with an optical element mounting substrate having an optical element mounting region on which an optical element is mounted, an electric circuit substrate having an opening larger than the optical element mounting substrate, and an optical path changing unit. An optical circuit board provided with an optical waveguide, wherein the optical circuit board and the electric circuit board are stacked such that the optical path conversion unit is disposed at a position facing the opening, and the optical circuit board is stacked in the opening. By fitting the element mounting substrate, the optical path changing portion and the optical element mounting area are arranged to face each other.

  Further, the circuit board of the present invention is an optical circuit board including an electric circuit board used by being laminated on an optical circuit board provided with an optical waveguide provided with an optical path conversion unit, and an optical element mounting area on which the optical element is mounted. And an opening into which the optical element mounting substrate can be fitted is formed through the electric circuit substrate.

  The photoelectric composite device of the present invention includes an optical element mounting substrate on which an optical element is mounted, an electric circuit substrate having an opening larger than the optical element mounting substrate, and an optical path conversion unit. An optical circuit board provided with an optical waveguide provided and laminated on the electric circuit board, wherein the optical element mounting substrate is fitted into the opening, and the optical element and the optical path conversion unit are arranged to face each other. Yes.

  According to the above invention, the optical path length which is the distance in the thickness direction between the optical element mounting region and the optical waveguide is reduced by fitting the optical element mounting board into the electric circuit board. For this reason, the merit of modularization of the optical element by the optical element mounting board | substrate can be enjoyed, reducing the optical coupling loss of the optical element mounted and the optical path conversion part.

  Note that the various components of the present invention do not have to be individually independent, that a plurality of components are formed as one member, and one component is formed of a plurality of members. That a certain component is a part of another component, a part of a certain component overlaps a part of another component, and the like.

  According to the present invention, it is possible to easily mount and modify the optical element, and to reduce the optical coupling loss between the optical element and the optical waveguide.

(A) is a perspective view which shows typically the photoelectric composite board | substrate concerning 1st embodiment, (b) is a perspective view which shows an optical element mounting substrate. It is a disassembled perspective view of the photoelectric composite board | substrate concerning 1st embodiment. 1 is a perspective view of a photoelectric composite device according to a first embodiment. It is a front view which shows the state which inserts the optical element mounting substrate concerning 1st embodiment in an opening part. It is a top view which shows typically the vicinity of an opening part and an optical element mounting substrate. (A) is a front view which shows the state which inserts the optical element mounting substrate concerning 2nd embodiment in an opening part, (b) is a front view of the photoelectric composite device concerning 2nd embodiment. It is a front view of the optical element mounting substrate concerning the modification of 2nd embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.
In the present embodiment, the vertical direction is defined and described. However, this is provided for convenience in order to explain the relative relationship between the components, and the product according to the present embodiment is manufactured or used. It does not limit the direction.

<First embodiment>
FIG. 1A is a perspective view schematically showing an optoelectric composite substrate 10 according to the first embodiment of the present invention, and FIG. 1B is a perspective view showing an optical element mounting substrate 20. FIG. 2 is an exploded perspective view of the photoelectric composite substrate 10 according to the present embodiment. FIG. 3 is a perspective view of the photoelectric composite device 14 according to the present embodiment.

  First, the outline | summary of the photoelectric composite board | substrate 10, the circuit board 12, and the photoelectric composite device 14 of this embodiment is demonstrated.

The optoelectric composite substrate 10 includes an optical element mounting substrate 20 including an optical element mounting region 22 on which the optical element 110 is mounted, an electric circuit substrate 30 including an opening 32 larger than the optical element mounting substrate 20, and an optical path conversion unit. And an optical circuit board 40 including an optical waveguide 42 provided with 44.
In the optoelectric composite substrate 10, the optical circuit board 40 and the electric circuit board 30 are laminated so that the optical path changing unit 44 is disposed at a position facing the opening 32, and the optical element mounting substrate 20 is fitted into the opening 32. As a result, the optical path changing unit 44 and the optical element mounting region 22 are arranged to face each other.

  According to such a configuration, the optical element 110 is modularized by the optical element mounting substrate 20 without being diffused, and the light L entering and exiting the optical path changing unit 44 and the optical element 110 (see FIG. 2) is mounted and modified. Workability is improved. If the optical element 110 fails, the optical element mounting board 20 can be easily repaired or replaced by removing the optical element mounting board 20 from the opening 32 without interfering with the electric circuit board 30 or the electric element 120 mounted thereon. Is possible.

The optical element mounting board 20 and the electric circuit board 30 constituting the optoelectric composite board 10 are collectively referred to as a circuit board 12.
That is, the circuit board 12 of the present embodiment is mounted on the optical circuit board 40 that is used by being laminated on the optical circuit board 40 including the optical waveguide 42 provided with the optical path conversion unit 44, and the optical element mounting on which the optical element 110 is mounted. And an optical element mounting substrate 20 having a region 22. In the circuit board 12 of the present embodiment, the electric circuit board 30 has an opening 32 through which the optical element mounting board 20 can be fitted.

Further, a substrate in which the optical element 110 and the electric element 120 are mounted on the photoelectric composite substrate 10 is collectively referred to as a photoelectric composite device 14.
That is, the photoelectric composite device 14 according to the present embodiment includes an optical element mounting substrate 20 on which the optical element 110 is mounted, and an electric circuit substrate on which the electric element 120 is mounted with an opening 32 larger than the optical element mounting substrate 20. 30 and an optical circuit board 40 provided with an optical waveguide 42 provided with an optical path changing unit 44 and laminated on the electric circuit board 30. In the photoelectric composite device 14 of the present embodiment, the optical element mounting substrate 20 is fitted into the opening 32, and the optical element 110 and the optical path changing unit 44 are disposed to face each other.

  Next, the photoelectric composite substrate 10 and the photoelectric composite device 14 of this embodiment will be described in detail.

The optoelectric composite substrate 10 is a substrate on which the optical element 110, its driving element 112, and the electric element 120 are mounted. The optoelectric composite substrate 10 is formed by bonding an optical circuit substrate 40 to a circuit substrate 12 composed of an electric circuit substrate 30 and an optical element mounting substrate 20. Examples of the optical element 110 include a light emitting element such as a surface emitting laser (VCSEL), a light receiving element such as a photodiode (PD, APD), and the like. For example, the drive element 112 is a combination of an amplifier such as a transimpedance amplifier (TIA) or a limiting amplifier (LA) and a driver IC for control.
As the electric element 120, various devices such as a resistor, a capacitor, and an inductor can be used in addition to a semiconductor device such as an LSI or an IC.

  The optical element mounting substrate 20 and the electric circuit substrate 30 may be a rigid substrate based on a hard material such as a glass epoxy substrate, or may be a flexible substrate based on a flexible film such as polyimide or polyester. Among these, the optical element mounting board 20 and the electric circuit board 30 are preferably rigid boards having a predetermined thickness from the viewpoint of easy fitting of the optical element mounting board 20 and good alignment accuracy.

  The optoelectric composite substrate 10 of this embodiment further includes a terminal portion 24 that protrudes outward from the optical element mounting substrate 20 and an electrode pad 34 provided on the surface of the electric circuit substrate 30. By fitting the optical element mounting substrate 20 into the opening 32, the tip of the terminal portion 24 is connected to the electrode pad 34.

  With this configuration, it is possible to easily electrically connect the optical element mounting substrate 20 and the electric circuit board 30 only by fitting the optical element mounting board 20 into the opening 32, and the large number of optical elements 110 can be connected to the electric circuit board. There is no need to bond to 30 individually.

  As shown in FIG. 1B, the optical element mounting substrate 20 is formed in the optical element mounting region 22 to mount the optical element 110, and is formed in the driving element mounting region 23 to form the optical element 110. The second electrode 27 for mounting the driving element 112 for driving the first electrode 26, and the driving circuit unit 28 for connecting the first electrode 26 and the second electrode 27 to the terminal unit 24 are included. The drive circuit unit 28 is formed inside the optical element mounting substrate 20. The base end side of the terminal portion 24 is connected to the drive circuit portion 28. The distal end portion 24 a of the terminal portion 24 is connected to an electrode pad 34 that is patterned on the surface of the electric circuit board 30.

  The optical element mounting region 22 is a region where the optical element 110 is to be mounted on the optical element mounting substrate 20, and is a partial region of the optical element mounting substrate 20 including at least a part of the first electrode 26. The drive element mounting region 23 is a region where the drive element 112 is to be mounted on the optical element mounting substrate 20, and is a partial region of the optical element mounting substrate 20 including at least a part of the second electrode 27.

  The electric circuit board 30 includes a wiring layer (not shown), and a large number of electric elements 120 and optical connectors 114 are individually mounted on electrode pads and connected to each other. The wiring layer is made of a conductive material, for example, a metal material such as Cu, Ni, Al, Au, or Pt. The optical connector 114 is a member that exchanges optical signals with the optical element 110. As shown in FIG. 2, the optical connector 114 may be mounted on the electric circuit board 30, or similarly to the optical element 110, the optical connector 114 may be mounted on the optical element mounting board 20 and fitted into the electric circuit board 30. You may connect.

  The opening 32 is a through hole formed in the electric circuit board 30. An electrode pad 34 is disposed in the vicinity of the opening 32 on the surface of the electric circuit board 30. The opening shape of the opening 32 is not particularly limited, but it is preferable that the opening portion 32 includes the optical element mounting substrate 20 and has a shape that substantially matches the optical element mounting substrate 20. In the present embodiment, the optical element mounting substrate 20 and the opening 32 both having a rectangular shape in plan view are illustrated.

The optical circuit board 40 is a board in which an optical waveguide 42 is formed on the surface or inside of a base material portion 48 that is attached to substantially the entire surface of the electric circuit board 30.
The optical waveguide 42 is provided with an optical path conversion unit 44 at an end or an intermediate part thereof. The optical path conversion unit 44 is an area in which light traveling in the plane of the base material portion 48 and light traveling in the crossing direction (typically in the perpendicular direction) with respect to the base material portion 48 are mutually converted. is there. The optical path conversion unit 44 is generally provided with an optical path conversion mirror 46 having a reflecting surface inclined. In the present embodiment, an example in which the optical path conversion mirror 46 is embedded in the optical waveguide 42 is illustrated. In the second embodiment to be described later, a mode in which the optical path conversion mirror 46 is fixed to the lower surface of the optical element mounting substrate 20 and is detachably attached to the optical waveguide 42 will be described. 1A and 2 illustrate a state in which the optical path conversion mirror 46 is exposed above the optical waveguide 42 for the sake of explanation.

  FIG. 4 is a front view showing a state in which the optical element mounting board 20 according to the present embodiment is fitted into the opening 32 of the electric circuit board 30.

  The optical path conversion mirror 46 of the present embodiment has a reflecting surface inclined at an angle of 45 degrees with respect to the extending direction of the optical waveguide 42, and the light traveling inside the optical waveguide 42 parallel to the base material portion 48 is reflected on the base. Reflects vertically upward with respect to the material part 48. The upward direction is the normal direction of the photoelectric composite substrate 10 from the optical circuit substrate 40 toward the electric circuit substrate 30 (or the optical element mounting substrate 20). The optical circuit board 40 is aligned and joined to the electric circuit board 30 so that the optical path changing unit 44 is accommodated in the opening 32. Then, the optical path conversion mirror 46 provided in the optical path conversion section 44 and the light emitting / receiving section 111 of the optical element 110 are aligned so that they coincide with the planar direction of the optoelectric composite substrate 10, and the optical element mounting substrate 20 is attached to the opening 32. As shown in FIG. 2, another optical path conversion mirror 46 is provided immediately below the optical connector 114 mounted on the electric circuit board 30 and at the end of the optical waveguide 42.

The optical waveguide 42 has a linear core portion 42a and a sheath-like clad portion 42b surrounding the core portion 42a. The core part 42a and the clad part 42b have different light refractive indexes. The optical circuit board 40 is an optical member that propagates light incident on the end portion or the intermediate portion of the core portion 42a while totally reflecting it at the interface between the core portion 42a and the clad portion 42b. A plurality of core parts 42a may be provided and separated from each other by the clad part 42b. The thickness of the optical waveguide 42 is preferably 15 to 200 μm, and more preferably 30 to 100 μm.
Hereinafter, the length direction of the optical waveguide 42, the core portion 42a, and the clad portion 42b refers to the left-right direction in FIG. 4, the thickness direction thereof refers to the up-down direction in FIG.

  The width of the core part 42a is preferably 1 to 200 μm, more preferably 5 to 100 μm, and further preferably 10 to 60 μm. 5-100 micrometers is preferable and, as for the thickness dimension of the core part 42a, 25-80 micrometers is more preferable. On the other hand, the thickness of the clad portion 42b is preferably 3 to 50 μm, and more preferably 5 to 30 μm.

  Each constituent material of the core part 42a and the clad part 42b is not particularly limited as long as it is a material that causes a difference in refractive index. Specifically, acrylic resins, methacrylic resins, polycarbonate, polystyrene, epoxy resins, polyamides, polyimides, polybenzoxazoles, polysilanes, polysilazanes, and cyclic olefin resins such as benzocyclobutene resins and norbornene resins In addition to such various resin materials, glass materials such as quartz glass and borosilicate glass can be selected and used.

  The base material portion 48 of the optical circuit board 40 can also be selected from the above materials. The base material portion 48 may be made of the same material as that of the clad portion 42b.

  Further, the optical path conversion mirror 46 of the present embodiment is formed inside the optical path conversion section 44 of the optical waveguide 42, and the refractive index on the inclined reflecting surface is different from that of the core section 42a. The optical path conversion mirror 46 of this embodiment can be formed by subjecting the optical waveguide 42 to laser processing or grinding processing. A reflective film may be formed on the reflective surface (mirror surface) of the optical path conversion mirror 46 as necessary. As the reflective film, a metal film such as Au, Ag, or Al is used.

  In the present embodiment shown in FIG. 4, the electric circuit board 30 is bonded to the front surface side of the optical circuit board 40, and the motherboard 130 is bonded to the back surface side. The mother board 130 is a multilayer printed circuit board. The mother board 130 may include another photoelectric composite substrate 10 (not shown) in the stack. In other words, the photoelectric composite substrate 10 of the present embodiment may be configured in multiple stages. Since the optoelectric composite substrate 10 of the present embodiment is in the substantially same plane with the optical element mounting substrate 20 and the electric circuit substrate 30 fitted together, the thickness dimension is suppressed as a whole. For this reason, by stacking the photoelectric composite substrates 10 in multiple stages, high mounting efficiency of the optical element 110 and the electric element 120 can be realized while suppressing the thickness dimension of the mother board 130.

  FIG. 5 is a plan view schematically showing the vicinity of the opening 32 of the electric circuit board 30 and the optical element mounting board 20.

Here, further effects of the photoelectric composite substrate 10 and the photoelectric composite device 14 of the present embodiment will be described. When the optical element 110 or the electric element 120 is mounted on the optoelectric composite substrate 10, for example, when a general reflow solder is used, the thermal distortion is caused by the difference in the linear expansion coefficient between the optical circuit substrate 40 and the electric circuit substrate 30. Occurs, and the relative position between the mounting area of the optical element 110 and the optical path changing unit 44 becomes a problem. In addition, there is a problem of individual difference due to a difference in position accuracy when the electric circuit board 30 and the optical circuit board 40 are stacked. Whereas the electric circuit board 30 and the optical circuit board 40 have a scale of several tens of centimeters (on the order of 100,000 μm), in the conventional photoelectric composite boards of Patent Documents 2 and 3, for example, light is transmitted through the electric circuit board. The passing aperture was a small hole having a diameter of about 100 μm at most. This is because the conventional photoelectric composite substrate needs to mount the optical element directly on the electric circuit board, so that the opening cannot be made larger than the optical element, and the opening is formed as a small hole directly under the light emitting / receiving section. This is because it was necessary to form. For this reason, in the conventional photoelectric composite substrate, the optical path conversion unit 44 (optical path conversion mirror 46) of the optical circuit board 40 is relatively moved with respect to the electric circuit board 30 due to thermal deformation at the time of solder mounting of the electric elements. The optical element 110 is difficult to adjust and mount because of being out of the small hole.
On the other hand, in the photoelectric composite substrate 10 and the photoelectric composite device 14 according to the present embodiment, the large opening portion 32 that can fit the optical element mounting substrate 20 on which the optical element 110 is mounted (for example, centimeter order) is provided. It is formed on the electric circuit board 30. For this reason, even if the optical circuit board 40 is thermally deformed, the optical path conversion unit 44 (optical path conversion mirror 46) can be reliably viewed from the opening 32. Therefore, the predicted position of the photoelectric composite device 14 in the operating temperature environment is determined from the visual position of the optical path conversion unit 44 (optical path conversion mirror 46) when the optical element mounting board 20 is fitted and mounted, and the optical element mounting board 20 ( The optical element 110) can be aligned and mounted on the electric circuit board 30.

As shown in FIG. 5, the electrode pad 34 of the present embodiment is in contact with the terminal portion 24 in accordance with the width dimension (ΔX, ΔY) of the gap portion 36 between the opening portion 32 and the optical element mounting substrate 20. It is formed larger than the terminal portion 24 in the separating direction (X direction) and its intersecting direction (Y direction). Here, the electrode pad 34 being larger than the terminal portion 24 means that the envelope region of the electrode pad 34 is larger than the envelope region of the mounting portion (including the tip portion 24a) of the terminal portion 24.
In FIG. 5, a large number of electrode pads 34 and terminal portions 24 are provided, and a part of repetition is not shown. As shown in the figure, when the terminal portion 24 is a terminal group composed of a plurality of terminals, the electrode pad 34 is larger than the terminal portion 24. The plurality of electrode pads 34 corresponding to the individual terminals are respectively connected to the tips. In addition to including the portion 24 a, each tip portion 24 a can be connected to the electrode pad 34 even when the entire terminal portion 24 (terminal group) is moved by a predetermined length with respect to the electric circuit board 30. .
In addition, the electrode pad 34 is formed to be larger than the terminal portion 24 corresponding to the width dimension (ΔX, ΔY) of the gap portion 36 when the electric circuit board 30 and the optical element mounting board 20 are aligned. The tip portion 24a of the band-shaped gap portion 36 generated in the (reference state) by the position (direction of the gap) and width (ΔX in the + X direction and ΔY in the −Y direction) as viewed from the optical element mounting substrate 20 Is movable relative to the electrode pad 34. The same applies to the width dimension of the gap portion 36 in the −X direction and the + Y direction with respect to the optical element mounting substrate 20.

  As described above, since the electrode pad 34 is formed larger than the terminal portion 24 by the width dimension (ΔX, ΔY) of the gap portion 36, the position of the optical element mounting substrate 20 in the opening portion 32 is various. Even if it fluctuates, the tip 24a of the terminal portion 24 and the electrode pad 34 can be connected. For this reason, the optical element mounting substrate 20 has a degree of freedom in selecting a fitting position with respect to the opening 32. Therefore, even when the positional deviation between the opening 32 and the optical path conversion unit 44 due to an error in the bonding position between the electric circuit board 30 and the optical circuit board 40 or thermal distortion between the two occurs, the fitting position of the optical element mounting board 20 Thus, the alignment of the light emitting / receiving unit 111 of the optical element 110 and the optical path conversion mirror 46 of the optical path conversion unit 44 can be adjusted with high accuracy.

  The electrode pad 34 is formed larger than the terminal portion 24, and the optical element mounting substrate 20 is loosely fitted into the opening 32. Here, the optical element mounting substrate 20 being loosely fitted into the opening 32 means that the opening 32 is formed larger than the optical element mounting substrate 20 in at least one direction in the plane. That is, in the state of the photoelectric composite device 14, the movement of the optical element mounting substrate 20 inside the opening 32 may be restricted, for example, the gap 36 is filled with the resin material 38. Also in this case, the optical element mounting substrate 20 is said to be loosely fitted in the opening 32.

  In the photoelectric composite device 14 of this embodiment, a thermoplastic or thermoplastic resin material 38 is filled between the opening 32 and the optical element mounting substrate 20 (gap 36).

  With such a configuration, the resin material 38 filled is softened by heating the optical element mounting substrate 20 or locally irradiating the optical element mounting substrate 20 with light such as ultraviolet rays. The mounting board 20 can be detached from the electric circuit board 30. For this reason, the optical element mounting substrate 20 can be fixed to the electric circuit board 30 during normal use of the opto-electric composite device 14, and if the optical element 110 fails, the optical element mounting substrate 20 Can be easily removed and repaired or replaced.

  In the photoelectric composite device 14 of the present embodiment, the optical circuit board 40 includes an alignment mark 66. The optical element mounting substrate 20 is fixed to the optical circuit substrate 40 by positioning pins 60.

  With this configuration, the alignment mark 66 can be used to align the optical element mounting substrate 20 with respect to the optical path conversion unit 44 (optical path conversion mirror 46) of the optical circuit board 40. Then, the positioning pins 60 are fixed to the optical circuit board 40 or the optical element mounting board 20 with the alignment adjusted. As a result, even when the optical element mounting substrate 20 is once removed from the electric circuit substrate 30 and repair or replacement of the optical element 110 is performed, the optical element mounting substrate 20 can easily be placed in the opening 32 with high alignment accuracy. It can be fitted again.

  In the present embodiment, for example, a plurality of alignment marks 66 such as a cross shape are provided on the optical element mounting substrate 20. These alignment marks 66 and the optical path conversion mirror 46 (or another alignment mark provided on the optical circuit board 40) facing the opening 32 are observed with an alignment device (not shown), and the optical element mounting substrate 20 is observed. And the optical waveguide 42 are aligned. Then, the positioning pins 60 are erected with respect to the optical circuit board 40 in a state where the optical element mounting board 20 is aligned with the optical waveguide 42 with desired position accuracy. For example, pin holes 64 are formed in three places on the optical element mounting substrate 20, and positioning pins 60 are erected on the optical circuit substrate 40 through the pin holes 64 of the optical element mounting substrate 20. As a result, only by inserting the positioning pins 60 placed on the optical circuit board 40 into the pin holes 64, the alignment between the optical element mounting board 20 and the optical circuit board 40 is automatically performed. In the case of this embodiment, one of the pin holes 64 is a circular hole having an opening diameter that fits with the positioning pin 60, and the other two are lengths in which one of the X direction and the Y direction is formed with a long diameter, respectively. It is a hole.

  The width dimension (ΔX, ΔY) of the gap 36 in the X direction and the Y direction is the expected value of the relative displacement between the optical circuit board 40 and the electric circuit board 30 due to thermal strain in the element mounting process, and the electric circuit board 30. Greater than the sum of the alignment accuracy when the optical circuit board 40 and the optical circuit board 40 are stacked. The electrode pad 34 is formed to have a sufficient size so that the terminal portion 24 can be mounted on the electrode pad 34 when the optical element mounting substrate 20 is attached to any position inside the opening 32.

  In other words, the circuit board 12 of the present embodiment includes the terminal portion 24 that is formed to protrude outward from the optical element mounting substrate 20, the contact / separation direction (X direction) with respect to the terminal portion 24 on the surface of the electric circuit board 30, and And an electrode pad 34 formed larger than the terminal portion 24 in the intersecting direction (Y direction). Then, the tip of the terminal portion 24 is connected to the electrode pad 34 by loosely fitting the optical element mounting substrate 20 into the opening 32.

  The terminal portion 24 extending from the optical element mounting substrate 20 is drawn from the optical element mounting substrate 20 in both the X direction and the Y direction. That is, the width dimension W (Y direction dimension in FIG. 5) of the terminal portion 24 is larger than the width dimension of the optical element mounting substrate 20. Here, the width dimension W of the terminal portion 24 is a dimension of an area that envelops all of the terminal group including a plurality of terminals provided along any one side of the optical element mounting substrate 20. Then, using the state where the optical element mounting substrate 20 is aligned with the center of the opening 32 as a reference state, the distal end portion 24a of each terminal may be positioned at the center of each electrode pad 34, respectively. Further, even if the optical element mounting substrate 20 is displaced in the X direction or the Y direction with respect to the opening 32 from the reference state (± ΔX, ± ΔY at the maximum), each terminal does not cause poor connection to the electrode pad 34. Thus, the contact / separation direction (X direction) dimension of each electrode pad 34 is preferably 2 · ΔX or more, and the width direction (Y direction) dimension is preferably 2 · ΔY or more (see FIG. 5). In the present embodiment, the terminal portion 24 (terminal group) is exemplified only on one side (the left side in FIG. 5) of the optical element mounting substrate 20, but the present invention is not limited to this. Terminal portions 24 (terminal groups) may be provided along a plurality of sides adjacent to or facing each other in the optical element mounting substrate 20.

  The optoelectric composite device 14 includes a fixing unit that removably fixes the optical element mounting substrate 20 fitted in the opening 32 to the electric circuit substrate 30.

  With this configuration, the optical element mounting substrate 20 does not unexpectedly shift in the opening 32, and high alignment between the optical path conversion unit 44 and the optical element 110 can be maintained. And since the fixation of the optical element mounting substrate 20 can be detached, workability such as repair and replacement of the optical element 110 is not impaired.

Examples of the fixing means include a peelable adhesive member such as the tape 62, and a pressing member that detachably presses the upper surface of the optical element mounting substrate 20 like a ridge. In FIG. 5, the tape 62 is illustrated by a two-dot chain line for explanation. The fixing means (tape 62) of the present embodiment fixes one side or a plurality of pieces of the optical element mounting substrate 20 to the electric circuit substrate 30.
The tape 62 is also used as a fixing means for fixing the distal end portion 24 a to the electrode pad 34. In this way, the optical element mounting substrate 20 and the electric circuit board 30, and the terminal portion 24 and the electrode pad 34 are detachably fixed, so that the optical element mounting board 20 is detached from the electric circuit board 30 and light is emitted. The work of exchanging or refurbishing the element 110 and the driving element 112 is easy.

<Second embodiment>
FIG. 6A is a front view showing a state in which the optical element mounting board 20 according to the present embodiment is fitted into the opening 32 of the electric circuit board 30. FIG. 2B is a front view of the photoelectric composite device 14 according to the present embodiment.

  In the present embodiment, an optical path conversion mirror 46 is provided so as to protrude to one surface side of the optical element mounting substrate 20, and the optical path conversion mirror 46 is fitted in the optical waveguide 42 by fitting the optical element mounting substrate 20 into the opening 32. It is characterized by penetrating into the optical path conversion unit 44.

  With this configuration, since the optical path conversion mirror 46 and the optical element mounting region 22 are integrally provided and the relative position does not change, the optical path conversion unit regardless of whether the electric circuit board 30 and the optical circuit board 40 are misaligned. High-accuracy light emission / reception between the optical element 44 and the optical element 110 is possible.

  More specifically, when the surface of the optical element mounting substrate 20 and the surface of the electric circuit substrate 30 are flush with each other, the optical path conversion mirror 46 penetrates into the optical waveguide 42 and exceeds the core portion 42a. It reaches a deep position. Here, that the optical path conversion mirror 46 reaches a position deeper than the core part 42a means that at least a part of the lower end of the optical path conversion mirror 46 reaches a position deeper than the core part 42a.

  The optical path conversion mirror 46 of this embodiment is made of a resin material. In this case, the optical path conversion mirror 46 is likely to be thermally distorted by a thermal load, and the alignment accuracy between the optical path conversion mirror 46 and the optical element mounting region 22 does not deteriorate. This is because the optical path conversion mirror 46 is provided on the optical element mounting substrate 20 even when a large thermal load acts on the optical circuit board 40 at the time of soldering the electric element 120 to the electric circuit board 30, for example. This is because the heat load does not act on the optical path conversion mirror 46.

The optical waveguide 42 of this embodiment also includes a core portion 42a and a cladding portion 42b having different refractive indexes.
A resin coupling portion 50 made of a resin material having a refractive index equivalent to that of the core portion 42 a is attached to the surface of the optical path conversion mirror 46, and optical path conversion is performed by fitting the optical element mounting substrate 20 into the opening 32. In the portion 44, the resin connecting portion 50 and the core portion 42a of the optical waveguide 42 are optically connected.

  As described above, the optical path conversion mirror 46 is light that travels in the in-plane direction (left-right direction in FIG. 6) through the core portion 42 a of the optical waveguide 42, and between the optical path conversion unit 44 and the optical element 110. The light traveling in the vertical direction (FIG. 6) is reflected and switched to each other. Here, when an air interface exists between the core part 42a and the optical path conversion mirror 46, light is unexpectedly reflected or scattered at the air interface and becomes signal noise. On the other hand, according to the above-described configuration of the present embodiment, the core portion 42a and the optical path conversion mirror 46 are optically coupled with the resin coupling portion 50 interposed therebetween, so that a high signal noise ratio (SN ratio) is achieved. Obtainable.

  Note that the refractive indexes of the resin connecting portion 50 and the core portion 42a are equivalent to the case where the resin connecting portion 50 and the core portion 42a are made of the same material and have the same refractive index, as well as the resin connecting portion 50 and the core portion. The case where the difference in refractive index from 42a is smaller than the difference in refractive index between the core part 42a and the cladding part 42b is included.

  In addition, an opening is formed in the optical element mounting substrate 20 immediately below the light emitting / receiving unit 111 so that the light reflected by the optical path conversion mirror 46 can pass through the electric circuit substrate 30 toward the light receiving / emitting unit 111. . A resin filling portion 52 is provided in this opening. For example, acrylic resin, polycarbonate resin, epoxy resin, silicone resin, or norbornene resin can be used for the resin filling portion 52. The resin filling part 52 has light transmittance (transparency). The resin filling unit 52 is filled over the entire optical path from the reflection surface of the optical path conversion mirror 46 to the light emitting / receiving unit 111.

  Accordingly, the optical path conversion mirror 46 and the resin coupling portion 50 are fitted and fitted to the optical path conversion portion 44 formed as a gap of the optical waveguide 42 in the intermediate portion of the optical circuit board 40, thereby FIG. As shown in b), the optical path between the optical circuit board 40 and the light emitting / receiving unit 111 is optically coupled via the optical path conversion mirror 46.

  As shown in the figure, a resin material 38 is filled between the optical element mounting substrate 20 and the electric circuit board 30, and the terminal portion 24 and the electrode pad 34 are fixed with a tape 62. The mounting substrate 20 and the optical circuit substrate 40 are relatively fixed, and the optical path of the light L is stabilized.

  The present invention is not limited to the above-described embodiment, and includes various modifications and improvements as long as the object of the present invention is achieved.

FIG. 7 is a front view of an optical element mounting substrate 20 according to a modification of the second embodiment.
As shown in the figure, a plurality of optical elements 110 may be mounted on the optical element mounting substrate 20, or one optical element 110 may include a plurality of light emitting / receiving units 111. In this case, it is effective to use an optical path conversion mirror 46 having a plurality of reflecting surfaces. In this modification, the resin coupling part 50 and the resin filling part 52 are mounted so as to cover each of the two reflecting surfaces of the optical path conversion mirror 46. As a result, in addition to light reception / emission with the outside of the optical element mounting substrate 20, the light waveguide 42 (not shown in FIG. 7) and the light reception / emission unit are also provided when light reception / emission is performed between the plurality of optical elements 110. No air interface is present in the optical path to the optical path 111, and the optical path is continued by the resin connecting part 50 and the resin filling part 52.

DESCRIPTION OF SYMBOLS 10 Photoelectric composite board | substrate 12 Circuit board 14 Photoelectric composite device 20 Optical element mounting board 22 Optical element mounting area 23 Drive element mounting area 24 Terminal part 24a Tip part 26 First electrode 27 Second electrode 28 Driving circuit part 30 Electric circuit board 32 Opening 34 Electrode Pad 36 Gap 38 Resin Material 40 Optical Circuit Board 42 Optical Waveguide 42a Core 42b Cladding 44 Optical Path Conversion 46 Optical Path Conversion Mirror 48 Base Material 50 Resin Connecting Portion 52 Resin Filling Portion 60 Positioning Pin 62 Tape 64 pin hole 66 alignment mark 110 optical element 111 light emitting / receiving unit 112 driving element 114 optical connector 120 electric element 130 motherboard L light W width dimension

Claims (12)

An optical element mounting substrate including an optical element mounting region on which an optical element is mounted, an electric circuit substrate including an opening larger than the optical element mounting substrate, and an optical circuit substrate including an optical waveguide provided with an optical path changing unit, Including,
The optical circuit board and the electric circuit board are stacked so that the optical path conversion unit is disposed at a position facing the opening, and the optical element mounting substrate is fitted into the opening to thereby form the optical path conversion unit. An optoelectric composite substrate on which the optical element mounting region is arranged to face.   A terminal portion projecting outward from the optical element mounting substrate; and an electrode pad provided on a surface of the electric circuit substrate; and by fitting the optical element mounting substrate into the opening, The photoelectric composite substrate according to claim 1, wherein a tip of the terminal portion is connected to the electrode pad.   The electrode pad is formed to be larger than the terminal portion in the contact / separation direction with respect to the terminal portion and in the intersecting direction corresponding to the width of the gap between the opening and the optical element mounting substrate. The optoelectric composite substrate according to claim 2.   An optical path conversion mirror is provided so as to protrude to one surface side of the optical element mounting substrate, and the optical path conversion mirror penetrates into the optical path conversion portion in the optical waveguide by fitting the optical element mounting substrate into the opening. The optoelectric composite substrate according to claim 1, wherein:   The photoelectric composite substrate according to claim 4, wherein the optical path conversion mirror is made of a resin material. The optical waveguide includes a core part and a clad part having different refractive indexes,
A resin coupling portion made of a resin material having a refractive index equivalent to that of the core portion is mounted on the surface of the optical path conversion mirror, and the optical element mounting substrate is fitted into the opening portion so that the optical path conversion portion 6. The photoelectric composite substrate according to claim 4, wherein the resin connecting portion and the core portion of the optical waveguide are optically connected. An electric circuit board used by being laminated on an optical circuit board including an optical waveguide provided with an optical path conversion unit, and an optical element mounting substrate including an optical element mounting region on which the optical element is mounted,
The circuit board, wherein an opening into which the optical element mounting board can be fitted is formed through the electric circuit board. A terminal part formed to protrude outward from the optical element mounting substrate;
An electrode pad formed on the surface of the electric circuit board that is larger than the terminal part in the direction of contact with and separating from the terminal part and in the direction intersecting the terminal part, and loosely fitting the optical element mounting board in the opening. The circuit board according to claim 7, wherein a tip of the terminal portion is connected to the electrode pad.   An optical element mounting board on which an optical element is mounted, an electric circuit board having an opening larger than the optical element mounting board and on which an electric element is mounted, and an optical waveguide on which an optical path conversion unit is provided. And an optical circuit board laminated on the optical device, wherein the optical element mounting substrate is fitted into the opening, and the optical element and the optical path conversion unit are arranged to face each other.   The photoelectric composite device according to claim 9, wherein a thermoplastic or thermoplastic resin material is filled between the opening and the optical element mounting substrate.   The photoelectric composite device according to claim 9 or 10, wherein the optical circuit board includes an alignment mark, and the optical element mounting board is fixed to the optical circuit board by a positioning pin.   The optoelectric composite device according to any one of claims 9 to 11, further comprising a fixing unit that removably fixes the optical element mounting substrate fitted in the opening to the electric circuit substrate.

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