JP6251989B2 - Opto-electric hybrid board and electronic equipment - Google Patents

Description

  The present invention relates to an opto-electric hybrid board and an electronic apparatus.

  An optical communication technique for transferring data using an optical carrier wave has been developed. In recent years, an optical waveguide has been widely used as a means for guiding the optical carrier wave from one point to another point. This optical waveguide has a linear core part and a clad part provided so as to cover the periphery thereof. The core part is made of a material that is substantially transparent to the light of the optical carrier wave, and the cladding part is made of a material having a refractive index lower than that of the core part.

  In the optical waveguide, light introduced from one end of the core portion is conveyed to the other end while being reflected at the boundary with the cladding portion. A light emitting element such as a semiconductor laser is disposed on the incident side of the optical waveguide, and a light receiving element such as a photodiode is disposed on the emission side. Light incident from the light emitting element propagates through the optical waveguide, is received by the light receiving element, and performs communication based on the flickering pattern of the received light or its intensity pattern.

  It has been studied to construct such an optical wiring by laying such an optical waveguide on a substrate. For example, in the electronic device described in Patent Document 1, a plurality of optical waveguides are laid on a substrate, and an electric wiring board on which light-emitting elements and light-receiving elements are mounted is disposed on the ends of the optical waveguides. Has been.

  By the way, such an optical wiring is often mounted in an electronic device for the purpose of replacing a part of the electrical wiring. For this reason, when space saving of the whole wiring is considered, the optical wiring is surface-mounted on the main substrate together with the electric wiring as described in Patent Document 1.

  On the other hand, a large number of electric elements are mounted on the substrate in addition to optical wiring and electric wiring. In recent years, there has been a strong demand for miniaturization of substrates, and along with this, the mounting density of electrical elements has also increased. However, since these electric elements need to be fixed to the substrate with solder or the like, it is difficult to coexist the electric element and the optical waveguide at the same position in plan view. For this reason, it is necessary to lay the optical waveguide so as to avoid the electric element, and it is also necessary to divide the optical waveguide into a plurality when the number of optical wirings is large. As a result, the higher the mounting density of electrical elements, the more complex the number of optical waveguides that must be laid, which increases the number of manufacturing steps and increases the total length of the optical waveguides, leading to an increase in transmission loss.

JP 2009-104064 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an opto-electric hybrid board in which optical wiring is freely laid without being restricted by the arrangement of electrical elements and the like, and enables high-density mounting of the electrical wiring and optical wiring, and the opto-electric hybrid board. It is providing the electronic device provided with.

Such an object is achieved by the present inventions (1) to (12) below.
(1) An electric wiring board comprising: a first substrate; an electric wiring laid inside or on the surface of the first substrate; and an electric element mounted on the first substrate;
A plurality of core portions provided so as to intersect with each other on the same plane, and a side clad portion provided adjacent to a side surface of each core portion, from the central portion of the core portion toward the side clad portion A core layer in which a refractive index distribution in which the refractive index continuously decreases, an optical path conversion unit that converts an optical path of the core unit, a metal layer provided on at least one surface side of the core layer, A film-shaped optical waveguide comprising:
Have
Between the optical waveguide and the electrical wiring board, configured to transmit and receive signals with photoelectric conversion,
The optical waveguide is disposed on the opposite side of the first substrate across the electrical element ,
The opto-electric hybrid board according to claim 1, wherein the metal layer is in direct contact with the electric element or in contact with a heat conducting part .

  (2) The opto-electric hybrid board according to (1), wherein the optical waveguide is detachably attached to the electric wiring board.

(3) The opto-electric hybrid board further includes a second substrate, an electrical wiring laid in or on the surface of the second substrate, and an optical element mounted on the second substrate. It has a conversion part,
The optical path included in the optical waveguide is optically connected to the optical element included in the photoelectric conversion unit, the electrical wiring included in the photoelectric conversion unit, and the electrical wiring included in the electrical wiring substrate; The opto-electric hybrid board according to (1) or (2), wherein are electrically connected.

  (4) The opto-electric hybrid board according to (3), wherein the electrical wiring of the photoelectric conversion unit and the electrical wiring of the electrical wiring board are electrically connected via an electrical connector.

  (5) The opto-electric hybrid board according to (3) or (4), wherein the photoelectric conversion unit further includes a heat dissipating member provided in contact with the optical element.

(6) The opto-electric hybrid board according to any one of (1) to (5), wherein the constituent material of the metal layer is mainly composed of aluminum, iron and copper alone or a base alloy thereof.

(7) The opto-electric hybrid board according to any one of (1) to (6) , wherein the optical waveguide is disposed so that a space is generated between the optical wiring board and the first board.

(8) Motherboard,
An electrical interposer mounted on the motherboard as the electrical wiring board;
The optical waveguide;
With
The optical waveguide according to any one of (1) to (7) , wherein the optical waveguide is disposed on the opposite side of the first substrate via the electric element so as to cover the electric element included in the electric interposer. The opto-electric hybrid board.

(9) The electrical wiring board includes metal layers provided on both sides of the first substrate, and via posts provided so as to connect the metal layers through the first substrate. The opto-electric hybrid board according to (8) .

(10) The opto-electric hybrid board according to any one of (1) to (9) , wherein the electrical wiring board includes a metal layer provided on at least one surface side of the first board.

(11) The opto-electric hybrid board according to any one of (1) to (10) , including the optical waveguide and an optical connector provided at an end of the core.

(12) An electronic apparatus comprising the opto-electric hybrid board according to any one of (1) to (11) .

  According to the present invention, it is possible to obtain an opto-electric hybrid board in which optical wiring is freely laid without being restricted by the arrangement of electric elements and the like, and high-density mounting of an electric circuit and optical wiring is possible.

  Moreover, since the optical waveguide on which the optical wiring is constructed can be easily removed, an opto-electric hybrid board that can be easily assembled and repaired can be obtained.

  In addition, according to the present invention, an electronic device that includes the opto-electric hybrid board and can be reduced in size and performance can be obtained.

It is a disassembled perspective view which shows 1st Embodiment of the opto-electric hybrid board of the present invention (partially see through). FIG. 2 is a cross-sectional view taken along line XX in a state where optical waveguides are overlapped as indicated by white arrows in FIG. 1. FIG. 2 is a perspective view showing a part of the optical waveguide shown in FIG. 1 in an enlarged manner (partially cut out and shown through). It is a figure which shows an example of the refractive index distribution in the width direction of the cross section of the core part of an optical waveguide. 5A is an example of a cross-sectional view cut across the core portion of the optical waveguide shown in FIG. 3, and FIG. 5B is a core layer of the cross-sectional view shown in FIG. 5A. It is a figure which shows typically an example of the refractive index distribution W on the centerline C1 which passes through the center of the thickness direction. 6A is another example of a cross-sectional view cut across the core portion of the optical waveguide shown in FIG. 3, and FIG. 6B is a cross-sectional view shown in FIG. It is a figure which shows typically the other example of the refractive index distribution W on the centerline C1 which passes the center of the thickness direction of a core layer. It is a figure which shows intensity distribution of the emitted light when light injects into the core part of the optical waveguide which has a refractive index distribution shown in FIG. FIG. 2 is a plan view showing the vicinity of an intersection of the optical waveguide shown in FIG. 1 and a diagram showing a refractive index distribution in the vicinity of the intersection. It is the elements on larger scale which show the other structural example vicinity of a cross | intersection part. It is a perspective view which shows the example in which the mirror (optical path conversion part) is formed in the middle of the core part of the optical waveguide shown in FIG. 2, and an extension line. FIG. 2 is an exploded perspective view of the optical connector shown in FIG. 1 and a perspective view of the optical connector shown in FIG. 1. It is sectional drawing which shows the other structural example of the optical module which concerns on 1st Embodiment. It is sectional drawing which shows a part of 2nd Embodiment of the opto-electric hybrid board | substrate of this invention. It is sectional drawing which shows a part of 3rd Embodiment of the opto-electric hybrid board | substrate of this invention. It is sectional drawing which shows a part of 4th Embodiment of the opto-electric hybrid board | substrate of this invention. It is a disassembled perspective view which shows 5th Embodiment of the opto-electric hybrid board of the present invention (partially see through). FIG. 17 is a cross-sectional view taken along line XX in a state where optical waveguides are stacked as indicated by white arrows in FIG. 16. FIG. 17 is a perspective view showing a part of the optical waveguide shown in FIG. 16 in an enlarged manner (partially cut out and shown through). It is sectional drawing which shows the other structural example of the optical module which concerns on 5th Embodiment. It is sectional drawing which shows a part of 6th Embodiment of the opto-electric hybrid board of this invention. It is sectional drawing which shows the other structural example of the optical module which concerns on 6th Embodiment. It is sectional drawing which shows a part of 7th Embodiment of the opto-electric hybrid board of this invention. It is sectional drawing which shows a part of 8th Embodiment of the opto-electric hybrid board | substrate of this invention. It is sectional drawing which shows a part of 9th Embodiment of the opto-electric hybrid board | substrate of this invention.

  The opto-electric hybrid board and electronic apparatus of the present invention will be described below in detail based on preferred embodiments shown in the accompanying drawings.

<Opto-electric hybrid board>
<< First Embodiment >>
First, a first embodiment of the opto-electric hybrid board according to the present invention will be described.

  FIG. 1 is an exploded perspective view showing a first embodiment of the opto-electric hybrid board according to the present invention (partially see through), and FIG. 2 is a state in which optical waveguides are stacked as shown by white arrows in FIG. It is XX sectional drawing in FIG.

  An optical module 100 shown in FIG. 1 includes an optical waveguide 1, an optical connector 101 provided at an end thereof, and a photoelectric conversion unit 4 provided below the optical waveguide 1. Further, the opto-electric hybrid board 1000 shown in FIG. 1 includes an optical module 100 and a mother board (electric wiring board) 5 provided below the photoelectric conversion unit 4.

  Among these, the optical waveguide 1 is a sheet-like member having a quadrangular shape in plan view. As shown in FIG. 2, the optical waveguide 1 is formed by laminating a clad layer 11, a core layer 13, and a clad layer 12 in this order from below, and a core portion 14 that propagates an optical signal to the core layer 13. Are formed in a desired pattern. In FIG. 1, the core portion 14 formed in the core layer 13 is indicated by a broken line together with the optical connector 101 and the photoelectric conversion portion 4 that are behind the optical waveguide 1.

  Moreover, the core part 14 is exposed to two opposite sides among the four sides of the optical waveguide 1, and the optical connector 101 is provided there. The optical wiring component 10 is configured to optically connect the core portion 14 of the optical waveguide 1 and other optical components via the optical connector 101. 1 illustrates an example in which the optical connector 101 is provided on two opposite sides of the optical waveguide 1, the arrangement of the optical connector 101 is not limited to this, and the optical connector 101 is provided on a side other than FIG. Alternatively, it may be provided at a portion other than the outer edge.

  A plurality of photoelectric conversion units 4 are provided on the lower surface of the optical waveguide 1. The photoelectric conversion unit 4 converts an electrical signal into an optical signal and sends it to the core unit 14 or receives an optical signal propagated through the core unit 14 and converts it into an electrical signal. The optical waveguide 1 is provided with a mirror (optical path conversion unit) 17 corresponding to the light receiving and emitting unit of the photoelectric conversion unit 4, and the optical path of the core unit 14 from the surface direction of the optical waveguide 1 by the mirror 17. It is converted in a direction perpendicular thereto, and the core portion 14 and the light receiving / emitting portion of the photoelectric conversion portion 4 are optically connected.

  On the other hand, a plurality of electric elements 50 for an electric wiring board such as a plurality of LSIs 501, capacitors 502, and chip resistors 503 are mounted on a mother board 5 provided below the photoelectric conversion unit 4. The photoelectric conversion unit 4 and the mother board 5 are electrically and mechanically connected via an electrical connector.

  In such an opto-electric hybrid board 1000, as shown in FIGS. 1 and 2, sheet-like optical waveguides 1 are stacked so as to cover a mother board (electric wiring board) 5. For this reason, when the opto-electric hybrid board 1000 is viewed from above, the electric circuit board electrical element 50 and the core part 14 can coexist in the same region, so the pattern of the core part 14 can be freely set. . That is, since the electric circuit and the optical wiring can be constructed in different levels, the electric circuit and the optical wiring can be freely designed in each level. As a result, for example, the distance between the core portions 14 can be minimized and the transmission efficiency of the optical signal can be optimized. In addition, since a margin is created in the region where the core portion 14 is formed, when a plurality of core portions 14 are formed, the interval between the adjacent core portions 14 can be widened to reduce crosstalk, and more Since the core part 14 can be formed, the density of the core part 14 can be increased. Furthermore, since it becomes easy to separate the optical waveguide 1 from the mother board 5, there is an advantage that the optical waveguide 1 and the electric element 50 for the electric wiring board can be easily replaced if necessary.

Hereinafter, each part of the opto-electric hybrid board 1000 will be described in detail.
(Optical waveguide)
First, the optical waveguide will be described.

  The optical waveguide 1 is a sheet-like member having a core portion 14 and a cladding portion, and is used as an optical wiring that transmits an optical signal from one end portion of the core portion 14 to the other end portion.

  FIG. 3 is an enlarged perspective view showing a part of the optical waveguide 1 shown in FIG. 1 (partially cut out and shown through).

((Core layer))
The optical waveguide 1 shown in FIG. 3 has three layers of a clad layer 11, a core layer 13, and a clad layer 12 from the lower side. Among these layers, the core layer 13 includes a long core portion 14, A side cladding portion 15 adjacent to the core portion 14 is formed. As a result, the core part 14 is surrounded by the clad part (the side clad part 15 and the clad layers 11 and 12), and can propagate light.

  Although the refractive index of the core part 14 should just be larger than the refractive index of a clad part, it is preferable that the difference is 0.3% or more, and it is more preferable that it is 0.5% or more. On the other hand, the upper limit value is not particularly set, but is preferably about 5.5%. If the difference in refractive index is less than the lower limit value, the effect of propagating light may be reduced. On the other hand, if the difference in refractive index exceeds the upper limit value, further improvement in light transmission efficiency cannot be expected.

The refractive index difference is expressed by the following equation when the refractive index of the core portion 14 is A and the refractive index of the cladding portion is B.
Refractive index difference (%) = | A / B-1 | × 100

  Further, the refractive index distribution in the cross section of the core portion 14 may be any shape distribution.

  FIG. 4 is a diagram illustrating an example of a refractive index distribution in the width direction of the cross section of the core portion 14 of the optical waveguide 1.

  This refractive index distribution may be a so-called step index (SI) type distribution in which the refractive index changes discontinuously as shown in FIG. 4A, and the refractive index distribution as shown in FIG. 4B. May be a so-called graded index (GI) type distribution in which the values continuously change. If the SI type distribution is used, it is easy to form a refractive index distribution. If the GI type distribution is used, the probability that the signal light is collected in a region having a high refractive index is increased, so that the transmission efficiency is improved.

  Further, as shown in FIG. 4C, the refractive index distribution has a shape in which the refractive index can be regarded as continuously changing although the refractive index changes stepwise. The distribution may also be The refractive index distribution shown in FIG. 4C is a distribution in which the refractive index changes stepwise, and the amount of change in the refractive index per step that changes in a stepped manner is the refractive index of the entire refractive index distribution. Since the amount of change in refractive index (refractive index difference) is sufficiently small (eg, 1/5 or less), the refractive index distribution as shown in FIG. . For this reason, the refractive index distribution shown in FIG. 4C has high transmission efficiency and can be easily formed.

  When the refractive index distribution is a GI type or a shape conforming thereto, the refractive index difference can be obtained by setting A as the maximum value of the refractive index in the core portion 14 and B as the minimum value of the refractive index in the cladding portion.

  In the distributions shown in FIGS. 4B and 4C, the refractive index change rate is preferably about 0.001 to 0.035 [/ 10 μm], and 0.002 to 0.030 [ / 10 μm] is more preferable. If the change rate of the refractive index is within the above range, effects such as a reduction in transmission loss, a reduction in the bluntness of the pulse signal, and suppression of crosstalk in each core portion 14 can be reliably obtained.

Hereinafter, the GI type refractive index distribution will be described in detail.
5A is an example of a cross-sectional view cut across the core portion of the optical waveguide shown in FIG. 3, and FIG. 5B is a core layer of the cross-sectional view shown in FIG. 5A. It is a figure which shows typically an example of the refractive index distribution W on the centerline C1 which passes the center of 13 thickness directions. In FIG. 5A, regarding the two long core portions 14 formed in the core layer 13 shown in FIG. 3, the left one is the core portion 141 and the right one is the core portion 142. . Similarly, for the three side clad parts 15 shown in FIG. 3, the left side is a side clad part 151, the center is the side clad part 152, and the right side is the side clad part 153.

  As shown in FIG. 5B, the refractive index distribution W is provided corresponding to the position of each core portion 14, and the refractive index continuously decreases toward both sides from the maximum value Wm and the maximum value Wm. A high refractive index region WH including two gradually decreasing portions and having a relatively high refractive index, and a low refractive index region WL provided corresponding to the position of each side cladding portion 15 and having a relatively low refractive index. Have. On both sides of the maximum value Wm in the high refractive index region WH, the refractive index continuously decreases toward the adjacent low refractive index region WL. That is, in the high refractive index region WH, the refractive index is distributed so that the maximum value Wm is at the apex and the both sides of the maximum value Wm are gradually lowered and lowered. On the other hand, in the low refractive index region WL, an almost constant refractive index is distributed which is lower than the refractive index of the high refractive index region WH.

  In addition, the plurality of maximum values Wm existing in the refractive index distribution W are preferably the same value, but may be slightly shifted. In this case, the deviation amount is preferably within 10% of the average value of the plurality of maximum values Wm.

  Note that the two core parts 14 arranged in parallel are each in the form of an elongated line, and the refractive index distribution W as described above is maintained substantially the same in the entire longitudinal direction of the core parts 14.

  On the other hand, the refractive index distribution W as described above is also formed in the core portion 14 intersecting with these core portions 14, and substantially the same distribution is maintained in the entire longitudinal direction of the core portion 14.

  Along with the refractive index distribution W as described above, the core layer 13 shown in FIG. 5 is formed with the core portion 14 and the side cladding portion 15 adjacent to the side surface thereof.

  More specifically, the core layer 13 shown in FIG. 5A includes two core portions 141 and 142 arranged in parallel and side clad portions 151, 152, and 153 provided in regions other than these core portions. Is provided. Thereby, each core part 141 and 142 will be in the state surrounded by each side cladding part 151,152,153 and each cladding layer 11,12, respectively. Here, since the refractive indexes of these core portions 141 and 142 are higher than the refractive indexes of the side cladding portions 151, 152, and 153, light can be confined in the width direction of the core portions 141 and 142. In addition, a dense dot is attached | subjected to each core part 14 shown to Fig.5 (a), and a sparse dot is attached | subjected to each side clad part 15. FIG.

  Further, in the optical waveguide 1, light incident on one end portion of the core portion 14 is propagated to the other while confining in the thickness direction of each core portion 14, so that the other end portion of the core portion 14 is transmitted. It can be taken out.

  In the refractive index distribution W, the refractive index changes continuously as a whole. Thereby, compared with an optical waveguide having a so-called step index type refractive index distribution in which the refractive index is changed stepwise, the effect of confining light in the core portion 14 is further enhanced, so that transmission loss can be further reduced.

  Further, in the refractive index distribution W, since the refractive index has a maximum value and the refractive index continuously changes, the speed of light increases as the distance from the center increases due to the property that the speed of light is inversely proportional to the refractive index. It is difficult for a difference in propagation time to occur. For this reason, the transmission waveform does not easily collapse, and for example, even when the transmission light includes a pulse signal, it is possible to suppress blunting of the pulse signal (spreading of the pulse signal). In addition, interference of transmitted light at the intersection is suppressed. As a result, the optical waveguide 1 that can further improve the quality of optical communication is obtained.

  Note that the refractive index continuously changing in the refractive index distribution W is a state in which the curve of the refractive index distribution W is rounded in each part and the curve is differentiable.

  Further, in the refractive index distribution W, the maximum value Wm is located in the core portions 141 and 142 as shown in FIG. 5A, but among the core portions 141 and 142, it is located in the center portion of the width. It is preferable. Thereby, in each core part 141 and 142, the probability that transmission light will gather in the center part of the width of core part 141 and 142 becomes high, and the probability that it will leak to side cladding parts 151, 152, and 153 becomes relatively low. As a result, the transmission loss of the core parts 141 and 142 can be further reduced.

  The central portion of the width of the core portion 141 is a region having a distance of 30% of the width of the high refractive index region WH on both sides from the center of the high refractive index region WH.

  Further, the difference between the maximum value Wm and the average refractive index in the low refractive index region WL is preferably as large as possible, but is preferably about 0.005 to 0.07, and is about 0.007 to 0.05. More preferably, it is about 0.01 to 0.03. Thereby, light can be reliably confined in the core portions 141 and 142. That is, when the refractive index difference is less than the lower limit value, light may leak from the core portions 141 and 142. On the other hand, when the difference in refractive index exceeds the upper limit value, further improvement in the effect of confining light cannot be expected, and the manufacture of the optical waveguide 1 becomes difficult.

  Further, as shown in FIG. 5B, the refractive index distribution W in the core portions 141 and 142 has a maximum value when the horizontal axis indicates the position of the cross section of the core layer 13 and the vertical axis indicates the refractive index. It is preferable that the shape in the vicinity of Wm is a substantially U shape convex upward. Thereby, the light confinement action in the core parts 141 and 142 becomes more remarkable.

  On the other hand, the amount of deviation from the average refractive index in the low refractive index region WL is preferably within 5% of the average refractive index. Thereby, the low refractive index region WL functions reliably as the side cladding portion 15.

  Here, according to the refractive index distribution W as described above, it is possible to obtain effects such as transmission loss reduction, pulse signal dullness reduction, crosstalk suppression, crosstalk suppression, and the like. The inventors have found that these effects are greatly influenced by the average width WCL of the side cladding part or the ratio of the average width WCO of the core part and the average width WCL of the side cladding part. And when these factors were in the predetermined range, it discovered that the above-mentioned effect became more remarkable and reliable.

  That is, in the present invention, the ratio (WCO / WCL) between the average width WCO of the core portion 14 and the average width WCL of the side cladding portion 15 is preferably in the range of 0.1 to 10. By optimizing the width ratio between the core portion 14 and the side clad portion 15, each effect described above can be enhanced. Therefore, for example, when WCO / WCL is less than the lower limit value, the average width of the core portion 14 becomes too narrow, so that crosstalk can be reduced, but transmission loss tends to increase, and the optical waveguide 1 can be downsized. May be hindered. Further, when WCO / WCL exceeds the upper limit value, the average width of the side cladding portion 15 becomes too narrow, so that crosstalk increases, and further, the average width of the core portion 14 becomes too wide. Dullness may increase.

  The WCO / WCL is more preferably about 0.1 to 5, and further preferably about 0.2 to 4.

  On the other hand, in the present invention, it is preferable that the average width WCL of the side cladding portion 15 be in the range of 5 to 250 μm independently of or in addition to WCO / WCL. Thereby, each effect mentioned above can each be advanced. Therefore, for example, when WCL is less than the lower limit value, the average width of the side clad portion 15 becomes too narrow, and there is a possibility that the dullness of the pulse signal increases or the crosstalk increases. Moreover, when WCL is more than the upper limit value, the shape of the refractive index distribution W cannot be optimized, and transmission loss may increase. Furthermore, there is a possibility that miniaturization of the optical waveguide 1 becomes difficult.

  The WCL is more preferably in the range of 10 to 200 μm, and still more preferably in the range of 10 to 120 μm.

  Further, the refractive index distribution W may include a flat portion in which the refractive index does not substantially change in the vicinity of each maximum value Wm. Even in this case, the optical waveguide of the present invention exhibits the effects and effects as described above. Here, the flat portion where the refractive index does not substantially change is a region where the refractive index fluctuation is less than 0.001, and the refractive index continuously decreases on both sides thereof. Say.

  Although the length of a flat part is not specifically limited, Preferably it is 100 micrometers or less, More preferably, it is 20 micrometers or less, More preferably, you may be 10 micrometers or less.

  In addition, the number of the core parts 14 is not specifically limited, Three or more may be sufficient. Also in this case, the refractive index distribution W has a high refractive index region WH corresponding to each core portion 14, and a low refractive index region WL exists between the high refractive index regions WH.

  Further, the refractive index distribution W may be a distribution having a minimum value between the high refractive index region WH and the low refractive index region WL. According to such a distribution, the function of confining and propagating light in a region having a high refractive index is enhanced, and transmission loss and blunting of the pulse signal can be suppressed particularly small.

  Further, in this case, the low refractive index region WL has a maximum value (this is referred to as “second maximum value”) that is smaller than the maximum value (this is referred to as “first maximum value”) included in the high refractive index region WH. ").) Is preferably included. By including such a second maximum value in the low refractive index region WL, crosstalk between core portions adjacent in the width direction is suppressed. As a result, even if a plurality of core portions are formed in the core layer 13 to be multi-channeled or the core portions 13 are narrowed to increase the density, the optical waveguide 1 can maintain high-quality optical communication. can do. And even when the several core part 14 mutually cross | intersects on the same plane, the interference of an optical signal will be suppressed.

  6A is another example of a cross-sectional view cut across the core portion of the optical waveguide shown in FIG. 3, and FIG. 6B is a cross-sectional view shown in FIG. It is a figure which shows typically the other example of the refractive index distribution W on the centerline C1 which passes the center of the thickness direction of the core layer.

  The refractive index distribution W shown in FIG. 6B has four minimum values Ws1, Ws2, Ws3, and Ws4, and five maximum values Wm1, Wm2, Wm3, Wm4, and Wm5. The five maximum values include a maximum value (first maximum value) Wm2 and Wm4 having a relatively high refractive index, and a maximum value (second maximum value) Wm1, Wm3 having a relatively low refractive index. Wm5 exists.

  Among these, the maximum value Wm2 and the maximum value Wm4 exist between the minimum value Ws1 and the minimum value Ws2, and between the minimum value Ws3 and the minimum value Ws4.

  In the optical waveguide 1 shown in FIG. 6, since the local maximum value Wm2 having a relatively large refractive index is located between the local minimum value Ws1 and the local minimum value Ws2, this region becomes the core portion 14, and similarly, Since the local maximum value Wm4 is located between the local minimum value Ws3 and the local minimum value Ws4, the core portion 14 is formed. Here, a core portion 141 is defined between the minimum value Ws1 and the minimum value Ws2, and a core portion 142 is defined between the minimum value Ws3 and the minimum value Ws4.

  Further, since the region on the left side of the minimum value Ws1, the region between the minimum value Ws2 and the minimum value Ws3, and the region on the right side of the minimum value Ws4 are regions adjacent to both side surfaces, the side cladding portion 15 is provided. It becomes. Here, the region on the left side of the minimum value Ws1 is the side cladding portion 151, the region between the minimum value Ws2 and the minimum value Ws3 is the side surface cladding portion 152, and the region on the right side of the minimum value Ws4 is the side surface cladding portion 153. .

  That is, the refractive index distribution W should have at least a region in which the second maximum value, the minimum value, the first maximum value, the minimum value, and the second maximum value are arranged in this order. Note that this region is repeatedly provided according to the number of core portions. When the number of core portions 14 is two as in the present embodiment, the refractive index distribution W has a second maximum value, a minimum value, and a first value. Local maximum values, local minimum values, second local maximum values, local minimum values, first local maximum values, local minimum values, second local maximum values, and the like. It is only necessary to have a region in which the maximum value of 1 and the second maximum value are alternately arranged.

  The plurality of local minimum values, the plurality of first local maximum values, and the plurality of second local maximum values are preferably substantially the same as each other, but the local minimum values are the first local maximum value and the second local maximum value. As long as the relationship that the second maximum value is smaller than the first maximum value and the second maximum value is smaller than the first maximum value is maintained, the values may be slightly different from each other. In that case, it is preferable that the amount of deviation is suppressed within 10% of the average value of the plurality of minimum values.

  Here, each of the four minimum values Ws1, Ws2, Ws3, and Ws4 is less than the average refractive index WA in the adjacent side cladding portion 15. As a result, a region having a smaller refractive index than the side cladding portion 15 exists at the boundary between each core portion 14 and each side cladding portion 15. As a result, a steeper refractive index gradient is formed in the vicinity of each local minimum value Ws1, Ws2, Ws3, and Ws4. This suppresses light leakage from each core portion 14, thereby reducing transmission loss. The optical waveguide 1 is obtained.

  Further, in the refractive index distribution W shown in FIG. 6B, the maximum values Wm1, Wm3, and Wm5 are located in the side cladding portions 151, 152, and 153. It is preferable to be located other than the vicinity of the edge (near the interface with the cores 141 and 142). As a result, the local maximum values Wm2, Wm4 in the core portions 141, 142 and the local maximum values Wm1, Wm3, Wm5 in the side cladding portions 151, 152, 153 are sufficiently separated from each other. , 142 can sufficiently reduce the probability that the transmitted light leaks into the side clad parts 151, 152, 153. As a result, the transmission loss of the core parts 141 and 142 can be reduced.

  Note that the vicinity of the edges of the side cladding portions 151, 152, and 153 is a region having a distance of 5% of the width of the side cladding portions 151, 152, and 153 from the above-described edge portion to the inside.

  In addition, the local maximum values Wm1, Wm3, Wm5 are located at the center of the width of the side cladding portions 151, 152, 153, and the local minimum values Ws1, Ws2, Ws3, which are adjacent to the local maximum values Wm1, Wm3, Wm5. It is preferable that the refractive index continuously decreases toward Ws4. As a result, the maximum distances between the maximum values Wm2, Wm4 in the core portions 141, 142 and the maximum values Wm1, Wm3, Wm5 in the side cladding portions 151, 152, 153 are secured, and the maximum values Wm1, Since light can be reliably confined in the vicinity of Wm3 and Wm5, leakage of transmission light from the core portions 141 and 142 described above can be more reliably suppressed.

  Furthermore, the local maximum values Wm1, Wm3, and Wm5 are smaller in refractive index than the local maximum values Wm2 and Wm4 located in the core portions 141 and 142 described above. Although it does not have, since the refractive index is higher than the surroundings, it has a slight light transmission property. As a result, the side clad parts 151, 152, and 153 have an effect of preventing transmission to other core parts by confining transmission light leaked from the core parts 141 and 142. That is, the presence of the maximum values Wm1, Wm3, and Wm5 can suppress crosstalk.

  Note that the minimum values Ws1, Ws2, Ws3, and Ws4 are less than the average refractive index WA of the adjacent side cladding portions 15 as described above, but the difference is desirably within a predetermined range. Specifically, the difference between the minimum value Ws1, Ws2, Ws3, Ws4 and the average refractive index WA of the side cladding portion 15 is the minimum value Ws1, Ws2, Ws3, Ws4 and the maximum value Wm2 in the core portions 141, 142. It is preferably about 3 to 80% of the difference from Wm4, more preferably about 5 to 50%, and still more preferably about 7 to 20%. As a result, the side clad portion 15 has a light transmission property necessary and sufficient for suppressing crosstalk. If the difference between the minimum value Ws1, Ws2, Ws3, Ws4 and the average refractive index WA of the side cladding 15 is below the lower limit, the light transmission in the side cladding 15 is too small and crosstalk is sufficient. If the value exceeds the upper limit, the light transmission property of the side cladding portion 15 is too large, and the light transmission properties of the core portions 141 and 142 may be adversely affected.

  The difference between the minimum values Ws1, Ws2, Ws3, Ws4 and the maximum values Wm1, Wm3, Wm5 is about 6 to 90% of the difference between the minimum values Ws1, Ws2, Ws3, Ws4 and the maximum values Wm2, Wm4. Is more preferable, about 10 to 70% is more preferable, and about 14 to 40% is further preferable. As a result, the balance between the refractive index height of the side cladding portion 15 and the refractive index height of the core portion 14 is optimized, and the optical waveguide 1 has particularly excellent optical transmission properties and more reliably suppresses crosstalk. It will be possible.

  The difference in refractive index between the minimum values Ws1, Ws2, Ws3, and Ws4 and the maximum values Wm2 and Wm4 in the core portions 141 and 142 is preferably as large as possible, but is about 0.005 to 0.07. Preferably, it is about 0.007 to 0.05, more preferably about 0.01 to 0.03. Thereby, the above-described difference in refractive index becomes necessary and sufficient for confining light in the core portions 141 and 142.

  Here, FIG. 7 is a diagram showing the intensity distribution of the emitted light when light is incident on the core portion 141 of the optical waveguide 1 having the refractive index distribution shown in FIG. This intensity distribution is the intensity distribution of the emitted light at the other end when the light is incident on the end of the core 141 out of the two parallel cores 141 and 142 formed in the optical waveguide 1.

  When light is incident on the core part 141, the intensity of the emitted light is highest at the center part of the emission end of the core part 141. The intensity of the emitted light decreases as the distance from the central portion of the core portion 141 decreases. However, in the optical waveguide 1, an intensity distribution is obtained such that a minimum value is obtained in the core portion 142 adjacent to the core portion 141. As described above, the minimum value of the intensity distribution of the emitted light matches the position of the core part 142, so that the crosstalk in the core part 142 can be suppressed to be extremely small. As a result, it is possible to obtain the optical waveguide 1 that can surely prevent the occurrence of crosstalk even by increasing the number of channels and increasing the density.

  In the conventional optical waveguide, the intensity distribution of the emitted light does not take the minimum value in the core portion adjacent to the core portion where the light is incident, but rather takes the maximum value, which causes a crosstalk problem. It was. On the other hand, the intensity distribution of the emitted light in the optical waveguide 1 according to the present embodiment as described above is extremely useful for suppressing crosstalk.

  Although the detailed reason why such an intensity distribution is obtained in the optical waveguide 1 according to the present embodiment is not clear, one reason is that the optical waveguide 1 has minimum values Ws1, Ws2, Ws3, and Ws4 and has a refractive index distribution. The characteristic refractive index distribution W in which the refractive index continuously changes over the entire W is the intensity distribution of the emitted light, which conventionally had a maximum value in the core 142, in the core 142. For example, it is shifted to the adjacent side clad portion 153 or the like. That is, the crosstalk is reliably suppressed by the shift of the intensity distribution.

  Even if the intensity distribution of the emitted light is shifted to the side clad portion 15, the light receiving element and the like are arranged in accordance with the position of the core portion 14, so there is almost no risk of crosstalk, and the quality of optical communication is improved. There is no deterioration.

  The intensity distribution of the emitted light as described above is not necessarily observed although there is a high probability of being observed when at least two core portions 14 are formed in parallel in the optical waveguide of the present invention. Depending on the NA (numerical aperture) of the incident light, the cross-sectional area of the core part 141, the pitch of the core parts 141, 142, etc., a clear minimum value is not observed, or the position of the minimum value deviates from the core part 142. Even in such a case, crosstalk is sufficiently suppressed.

  Further, in the refractive index distribution W shown in FIG. 6B, when the average refractive index in the side cladding portion 15 is WA, the refractive index in the vicinity of the maximum values Wm2 and Wm4 is continuously equal to or higher than the average refractive index WA. Is a [μm], and the width of the portion where the refractive index in the vicinity of the minimum values Ws1, Ws2, Ws3, and Ws4 is continuously less than the average refractive index WA is b [μm]. At this time, b is preferably about 0.01a to 1.2a, more preferably about 0.03a to 1a, and further preferably about 0.1a to 0.8a. As a result, the substantial widths of the minimum values Ws1, Ws2, Ws3, and Ws4 become necessary and sufficient for providing the above-described functions and effects. That is, when b is below the lower limit value, the substantial widths of the minimum values Ws1, Ws2, Ws3, and Ws4 are too narrow, and the action of confining light in the core portions 141 and 142 may be reduced. On the other hand, when b exceeds the upper limit value, the substantial widths of the local minimum values Ws1, Ws2, Ws3, and Ws4 are too wide, and the width and pitch of the core portions 141 and 142 are limited accordingly, and transmission is performed. There is a possibility that the efficiency may be lowered and the increase in the number of channels and the increase in density may be hindered.

  The average refractive index WA in the side cladding 15 can be approximated at the midpoint between the maximum value Wm1 and the minimum value Ws1.

  The refractive index distribution W is, for example, (1) a method of observing a refractive index dependent interference fringe using an interference microscope (dual-beam interference microscope) and specifying the refractive index distribution N from the interference fringe. ) Refraction Near Field Method (RNF) or the like. Among these, the refractive near field method can employ the measurement conditions described in, for example, JP-A-5-332880. On the other hand, the interference microscope is useful in that the refractive index distribution W can be easily specified.

  The core portion 14 may be linear or curved in plan view. Furthermore, the core part 14 may cross | intersecting on the way and may branch as needed. As shown in FIG. 1, since the optical signals can be crossed in the same plane by crossing the core portions 14 in the middle, the core having the shortest distance pattern without being crossed or detoured. The portion 14 can be formed. As a result, it is possible to minimize a decrease in transmission efficiency, a dull pulse signal, and the like in the optical waveguide 1. In this case, the refractive index distribution is preferably a distribution as shown in FIG. 4 (b), FIG. 4 (c), FIG. 5 (b) or FIG. 6 (b). Thereby, the interference of the optical signal in an intersection can be suppressed especially.

  The cross-sectional shape of the core portion 14 is not particularly limited, and may be a circle such as a perfect circle, an ellipse, or an oval, or a polygon such as a triangle, a quadrangle, a pentagon, or a hexagon. By being (rectangular shape), the core part 14 of the stable quality can be manufactured efficiently.

  The height of the core portion 14 (the thickness of the core layer 13) is not particularly limited, but is preferably about 1 to 200 μm, more preferably about 5 to 100 μm, and about 10 to 70 μm. More preferably. Thereby, it is possible to reduce the thickness of the core portion 14 while suppressing a decrease in transmission efficiency of the optical waveguide 1.

  The constituent material (main material) of the core layer 13 as described above is, for example, acrylic resin, methacrylic resin, polycarbonate, polystyrene, cyclic ether resin such as epoxy resin or oxetane resin, polyamide, polyimide, poly Benzoxazole, polysilane, polysilazane, silicone resin, fluorine resin, polyurethane, polyolefin resin, polybutadiene, polyisoprene, polychloroprene, polyester such as PET and PBT, polyethylene succinate, polysulfone, polyether, benzocyclo In addition to various resin materials such as cyclic olefin resins such as butene resin and norbornene resin, glass materials such as quartz glass and borosilicate glass can be used. Note that the resin material may be a composite material in which materials having different compositions are combined.

  Among these, at least one selected from the group consisting of (meth) acrylic resins, epoxy resins, silicone resins, polyimide resins, fluorine resins, and polyolefin resins is particularly preferable. A resin or epoxy resin is more preferable. Since these resin materials have high light transmittance, the optical waveguide 1 with particularly small transmission loss can be obtained.

((Clad layer))
On the other hand, the clad layers 11 and 12 are located below and above the core layer 13.
The average thickness of the cladding layers 11 and 12 is preferably about 0.05 to 1.5 times the average thickness of the core layer 13, and more preferably about 0.1 to 1.25 times. Specifically, the average thickness of the cladding layers 11 and 12 is preferably about 1 to 200 μm, more preferably about 3 to 100 μm, and further preferably about 5 to 60 μm. Thereby, the function as a clad part is ensured while preventing the optical waveguide 1 from becoming thicker than necessary. Moreover, moderate rigidity is given to the optical waveguide 1. For example, even when there is a space between the optical waveguide 1 and the mother board 5, the optical waveguide 1 becomes difficult to bend, and an optical path shift in the optical coupling portion can be suppressed. .

  Further, as the constituent material of the cladding layers 11 and 12, for example, the same material as the constituent material of the core layer 13 described above can be used, and in particular, (meth) acrylic resin, epoxy resin, silicone resin, It is preferably at least one selected from the group consisting of polyimide resins, fluorine resins, and polyolefin resins, and (meth) acrylic resins or epoxy resins are more preferable.

  Also, the refractive index distribution in the thickness direction of the cross section of the optical waveguide 1 may be an SI-type or GI-type distribution, or a distribution as shown in FIG.

  Since the optical waveguide 1 is disposed on the mother board 5 as will be described later, the size in plan view is preferably set to a size that can cover at least a part of the mother board 5, for example. Specifically, the major axis is preferably set to about 50 mm to 3000 mm.

  Moreover, the planar view shape of the optical waveguide 1 is not particularly limited, but may be a circle, an ellipse, or the like in addition to a polygon such as a quadrangle or a hexagon.

((Intersection))
FIG. 8 is a plan view showing the vicinity of the intersection of the optical waveguide 1 shown in FIG. 1 and a diagram showing the refractive index distribution in the vicinity of the intersection.

  As shown in FIG. 8, the intersecting portion 147 between the core portions 14 has a maximum value at the center portion, and the refractive index gradually decreases so as to draw a skirt toward the periphery (side clad portion 15). It preferably has a rate distribution. As a result, signal light easily gathers at the center of the intersection 147, so that interference at the intersection 147 is particularly suppressed.

  And it is preferable that the refractive index of the crossing part 147 is high compared with the circumference | surroundings. Based on this refractive index difference, the signal light that has entered the intersection 147 is less likely to enter the core 14 that intersects the core 14 through which the signal light has propagated. As a result, in the optical waveguide 1, interference of optical signals can be suppressed at the intersection 147. In this way, optical signals can be crossed on the same plane without making a three-dimensional intersection. As a result, the device (for example, the opto-electric hybrid board 1000) on which the optical waveguide 1 is mounted can be easily reduced in size, thickness, and density.

  The maximum refractive index of the intersecting portion 147 is preferably about 0.001 to 0.05 higher than the maximum refractive index in the core portion 14 other than the intersecting portion 147, and more preferably about 0.002 to 0.03 higher. .

  Here, the crossing angle of the optical axes of the intersecting core portions 14 is preferably 10 to 90 °, and more preferably 20 to 90 °. If the crossing angle is within this range, the occurrence of interference can be sufficiently suppressed. In addition, this intersection angle means an inner angle with a smaller angle among the inner angles formed by the intersecting optical axes.

  Note that, at the intersection 147 as described above, interference is suppressed and transmission loss of an optical signal when passing through one intersection 147 is suppressed to 0.02 dB or less. For this reason, even if the pattern of the core part 14 is set so that a plurality of core parts 14 intersect one core part 14, the transmission loss can be suppressed to be small, and an optical wiring having a complicated pattern is constructed. Can do.

FIG. 9 is a partially enlarged view showing another configuration example near the intersection.
Each of the optical waveguides shown in FIGS. 9A and 9B is configured so that the width of the core portion 14 gradually increases in the vicinity of the intersecting portion 147 toward the intersecting portion 147. Among these, in the optical waveguide shown in FIG. 9A, the width of the core portion 14 gradually increases linearly, whereas in the optical waveguide shown in FIG. 9B, the width of the core portion 14 increases gradually in a curve. Yes. With such a structure, interference at the intersection 147 is particularly suppressed, and transmission efficiency at the intersection 147 is improved.

  In the intersecting portion 148 shown in FIG. 9C, the three core portions 14 intersect, and the intersecting angle is set to 60 °. On the other hand, in the intersecting portion 148 shown in FIG. 9 (d), the four core portions 14 intersect, and the intersecting angle is set to 45 °.

  The number of core portions 14 that intersect at the intersection 148 may be five or more, and in that case, the number of intersections is appropriately set so that the intersection angle is within the above range. Moreover, each crossing angle may be equal to or different from each other.

((mirror))
A mirror 17 is provided in the optical waveguide 1 shown in FIG.
FIG. 10A is a perspective view showing an example in which a mirror (optical path changing unit) 17 is formed in the middle of the core part 14 of the optical waveguide 1 shown in FIG.

  In the optical waveguide 1 shown in FIG. 10A, a concave portion (hole) 170 having a V-shaped cross section is formed in the middle of the core portion 14 so as to penetrate the core portion 14 in the thickness direction. Yes. The mirror 17 is constituted by a part of the inner surface of the recess 170. The mirror 17 has a planar shape and is inclined by 45 ° with respect to the axis (optical axis) of the core portion 14. The light propagating through the core portion 14 is reflected by the mirror 17, and the optical path is converted by 90 ° downward in FIG. 10 (a). Further, the light propagating from below in FIG. 10A is reflected by the mirror 17 and enters the core portion 14. That is, the mirror 17 has an optical path conversion function for converting the optical path of light propagating through the core unit 14.

  If necessary, a reflective film may be formed on the surface of the processed surface constituting the mirror 17. Examples of the reflective film include a metal film such as Au, Ag, and Al, and a film made of a material having a lower refractive index than the core portion 14. Examples of the metal film forming method include physical vapor deposition such as vacuum vapor deposition, chemical vapor deposition such as CVD, and plating.

  Further, the mirror 17 may be provided not in the middle of the core part 14 but on the extension line of the core part 14 in the side clad part 15 as shown in FIG.

  The mirror 17 can be replaced with another optical path conversion unit such as a curved waveguide.

  Moreover, as shown in FIG. 3, the support film 2 may be provided in the lower surface of the optical waveguide 1, and the cover film 3 may be provided in the upper surface as needed, respectively.

  Examples of the constituent material of the support film 2 and the cover film 3 include various resin materials such as polyethylene terephthalate (PET), polyolefin such as polyethylene and polypropylene, polyimide, and polyamide.

  Moreover, although the average thickness of the support film 2 and the cover film 3 is not specifically limited, It is preferable that it is about 5-500 micrometers, and it is more preferable that it is about 10-400 micrometers. Thereby, since the support film 2 and the cover film 3 have moderate rigidity, while supporting the optical waveguide 1 reliably, the optical waveguide 1 can be reliably protected from external force and an external environment.

  In the optical waveguide 1 shown in FIG. 2, a lens 16 is provided on the lower surface of the cladding layer 11. The lens 16 converges the signal light passing between the mirror 17 and the optical element 6 and contributes to increasing the optical coupling efficiency.

  Examples of the constituent material of the lens 16 include various resin materials such as acrylic resin, various glass materials such as quartz glass, and the like.

  Further, the lens 16 may be a lens obtained by deforming a part of the clad layer 11 and imparting a function as a lens. For this deformation, for example, a nanoimprint technique or the like is used.

  The size and shape of the optical waveguide 1 in a plan view are appropriately set according to the size and shape of the mother board 5 and are not particularly limited. However, as an example, a rectangular shape having a side of about 20 mm to 2000 mm Is done. Further, the shape may be a circle, a polygon or the like.

(Optical connector)
The optical connector 101 is provided at the end of the optical waveguide 1 and can optically connect the core portion 14 to other optical components. The optical connector 101 may be compliant with various connector standards, such as a mini MT connector, an MT connector defined in JIS C 5981, a 16 MT connector, a two-dimensional array MT connector, an MPO connector, MPX connector etc. are mentioned.

  11A is an exploded perspective view of the optical connector 101 shown in FIG. 1, and FIG. 11B is a perspective view of the optical connector 101 shown in FIG.

  In the case of the optical connector 101 shown in FIG. 11, a notch 1c is provided in the vicinity of the core portion 14 to which the optical connector 101 is attached. Specifically, notches 1c having the same length as the optical connector 101 to be mounted are formed on both sides of the core portion 14, respectively.

  An optical connector 101 shown in FIG. 11 has a connector main body 1011 having two legs 1012 and a connector lid 1013 that can be attached to the connector main body 1011. As shown in FIG. 11B, the two legs 1012 of the connector main body 1011 can be fitted into the notches 1c, respectively. As a result, the core is interposed between the two legs 1012 of the connector main body 1011. The part 14 is inserted.

  The connector lid 1013 is also inserted between the two leg portions 1012 together with the core portion 14, and as a result, as shown in FIG. 11B, the connector body 1011, the connector lid 1013, The core portion 14 is sandwiched between and fixed.

  When the optical connector 101 is attached to the optical waveguide 1, the end portion of the core portion 14 is exposed from the end surface of the optical connector 101 as shown in FIG. By connecting another connector to the optical connector 101, for example, the core part 14 and another optical component such as another optical waveguide or optical fiber can be optically connected. Examples of the optical component to be connected include a wavelength conversion element, a filter, a diffraction grating, a polarizer, a prism, and a lens in addition to the optical waveguide and the optical fiber.

  Examples of the constituent material of the optical connector 101 include a resin material, a metal material, and a ceramic material.

  Further, the structure of the optical connector 101 is not limited to the structure shown in FIG. For example, the optical connector 101 may be configured to protrude from the end face of the optical waveguide 1, and in that case, it is not necessary to provide the notch 1 c in the optical waveguide 1. Further, the optical connector 101 may be configured such that the connector main body 1011 is simply bonded onto the end of the optical waveguide 1 without projecting the optical waveguide 1 or providing the notch 1c.

  In addition, the pattern of the core part 14 in the optical waveguide 1 is not limited to what is shown in FIG. 1, What kind of pattern may be sufficient.

(Photoelectric converter)
The photoelectric conversion unit 4 includes a photoelectric conversion unit substrate 41 provided below the optical waveguide 1, an optical element 6 and a photoelectric conversion unit electrical element 7 mounted on the lower surface of the photoelectric conversion unit substrate 41, an electrical connector 42, and the like. ,have. The photoelectric conversion unit 4 is bonded to the lower surface of the optical waveguide 1 by a fixing member such as an adhesive. Hereinafter, each part of the photoelectric conversion unit 4 will be described in detail.

((Photoelectric conversion part substrate))
As shown in FIG. 2, the photoelectric conversion unit substrate 41 includes an insulating substrate (second substrate) 411, electric wirings 412 provided on both surfaces thereof, and through wiring 413 that connects the electric wirings 412 on each surface. And a through hole 414 that penetrates the insulating substrate 411 and the like.

  Examples of the material constituting the insulating substrate 411 include various resin materials such as polyimide resins, polyamide resins, epoxy resins, various vinyl resins, and polyester resins such as polyethylene terephthalate resins. A resin mainly composed of a resin is preferably used. A polyimide resin is particularly suitable as a constituent material of the insulating substrate 411 because it has high heat resistance and excellent translucency and flexibility. Specific examples of the insulating substrate 411 include film substrates used for polyester copper-clad film substrates, polyimide copper-clad film substrates, aramid copper-clad film substrates, and the like.

  Here, in the optical module 100 shown in FIG. 2, the insulating substrate 411 is provided between the optical element 6 and the optical waveguide 1, and the signal light passes through the through hole 414 provided in the insulating substrate 411. To do. Note that when an insulating substrate 411 having a light-transmitting property is used, a through hole is not necessary.

  The average thickness of the insulating substrate 411 is preferably about 5 to 200 μm, and more preferably about 10 to 150 μm. With the insulating substrate 411 having such a thickness, the optical module 100 can be thinned and transmission loss of the insulating substrate 411 is suppressed. Furthermore, if the thickness of the insulating substrate 411 is within the above range, the distance between the mirror 17 and the optical element 6 is sufficiently short, so that it is possible to prevent the transmission efficiency from being lowered due to the divergence of signal light. .

  The insulating substrate 411 may be a single substrate or a multilayer substrate (build-up substrate) formed by stacking a plurality of substrates. In this case, an arbitrary electric circuit may be formed between the layers of the multilayer substrate. Thereby, a high-density electric circuit can be constructed in the insulating substrate 411.

  The insulating substrate 411 can be replaced with an insulating layer formed or laminated on the lower surface of the optical waveguide 1.

  The insulating layer is composed of a silicon compound such as silicon oxide or silicon nitride, a resin material such as polyimide resin or epoxy resin, or the like. As the film formation method, for example, a physical vapor deposition method such as vacuum vapor deposition or sputtering, a chemical vapor deposition method such as plasma CVD or thermal CVD, a liquid phase film formation method such as a coating method, or a printing method is used.

  The electric wiring 412 and the through wiring 413 are each made of a conductive material. Examples of the conductive material include metal materials such as simple metals such as copper, aluminum, nickel, chromium, zinc, tin, gold, and silver, or alloys containing these metal elements.

  Moreover, although the average thickness of the electrical wiring 412 is appropriately set according to the conductivity required for the wiring, it is set to about 1 to 30 μm, for example.

  In addition, the mounting method of the optical element 6 or the photoelectric conversion unit electrical element 7 on the photoelectric conversion unit substrate 41 is not particularly limited, and a die bonding method, a wire bonding method, or the like is used.

((Optical element))
The optical element 6 shown in FIG. 2 includes an element body 60, and a light emitting / receiving unit 61 and a terminal 62 provided on the upper surface of the element body 60. The light emitting / receiving unit refers to a light receiving unit, a light emitting unit, or a unit having both functions. The light receiving / emitting unit 61 of the optical element 6 and the mirror 17 of the optical waveguide 1 are optically connected.

  Examples of the optical element 6 include a light emitting element such as a surface emitting laser (VCSEL) and a light emitting diode (LED), and a light receiving element such as a photodiode (PD, APD).

  Further, the terminal 62 of the optical element 6 and the electric wiring 412 of the photoelectric conversion unit 4 are electrically connected via bumps. This bump is made of various metal materials.

((Electric element for photoelectric conversion part))
The photoelectric conversion unit electrical element 7 shown in FIG. 2 includes an element body 70 and a terminal 72 provided on the upper surface of the element body 70.

  As the electric element 7 for the photoelectric conversion unit, for example, a driver IC, a transimpedance amplifier (TIA), a limiting amplifier (LA), or a combination IC, LSI, RAM, ROM, capacitor, coil, resistor, or a combination of these elements. And diodes.

  Further, the terminal 72 of the photoelectric conversion unit electrical element 7 and the electrical wiring 412 of the photoelectric conversion unit 4 are electrically connected via bumps. Optical communication is performed in the core portion 14 of the optical module 100 by providing the photoelectric conversion portion 4 including the optical element 6 and the photoelectric conversion portion electrical element 7 at both ends of the core portion 14 of the optical waveguide 1. Can do.

  In addition, the electrical connection between the optical element 6 or the photoelectric conversion unit electrical element 7 and the electrical wiring 412 is performed by wire bonding, an anisotropic conductive film (ADF), an anisotropic conductive paste, in addition to the connection method described above. A connection method using (ACP) or the like may be used.

  Further, a sealing material 45 is provided between the optical element 6 and the photoelectric conversion unit electrical element 7 shown in FIG. 2 and the photoelectric conversion unit substrate 41. Examples of the sealing material 45 include an epoxy resin, a polyester resin, a polyurethane resin, and a silicone resin.

((Electrical connector))
The photoelectric conversion unit 4 is electrically connected to the mother board 5 via the electrical connector 42.

  The electrical connector 42 may be a connector conforming to various connector standards or a general-purpose product, and examples thereof include a board-to-board connector, an FPC / FFC connector, a ZIF connector, and a NON-ZIF connector.

  The optical waveguide 1 may be mechanically connected to the mother board 5 via the electrical connector 42. With such a fixing method, the optical waveguide 1 can be attached to and detached from the mother board 5. Thereby, since it becomes easy to separate the motherboard 5 and the optical waveguide 1, there is an advantage that the optical waveguide 1 can be easily replaced, for example.

(Motherboard)
The mother board (electric wiring board) 5 includes an insulating board (first board) 51, electric wiring 52 provided on the upper surface thereof, a plurality of LSIs 501, capacitors 502 and chip resistors mounted on the insulating board 51. A plurality of electrical elements 50 for electrical wiring boards, such as 503, and electrical connectors 53 are provided.

  The electrical connector 53 is fitted to the electrical connector 42 of the photoelectric conversion unit 4, and the electrical wiring 52 on the mother board 5 side and the electrical wiring 412 on the photoelectric conversion unit 4 side are electrically and mechanically connected by this fitting. And the operation of the optical element 6 of the photoelectric conversion unit 4 and the electric element 7 for the photoelectric conversion unit can be controlled from the mother board 5 side. In addition, transmission / reception of signals becomes possible.

  Examples of the material constituting the insulating substrate 51 include various resin materials such as polyimide resins, polyamide resins, epoxy resins, various vinyl resins, and polyester resins such as polyethylene terephthalate resins. In addition, paper, glass cloth, resin film, etc. are used as a base material, and this base material is impregnated with a resin material such as a phenol resin, a polyester resin, an epoxy resin, a cyanate resin, a polyimide resin, or a fluorine resin. In addition to insulating substrates used for composite copper-clad laminates such as glass cloth / epoxy copper-clad laminates, glass nonwoven fabrics / epoxy copper-clad laminates, polyetherimide resin substrates, polyethers It may be a heat-resistant / thermoplastic organic rigid substrate such as a ketone resin substrate or a polysulfone resin substrate, or a ceramic rigid substrate such as an alumina substrate, an aluminum nitride substrate, or a silicon carbide substrate.

  The electric wiring 52 is made of a conductive material. Examples of the conductive material include metal materials such as simple metals such as copper, aluminum, nickel, chromium, zinc, tin, gold, and silver, or alloys containing these metal elements.

  Moreover, although the average thickness of the electric wiring 52 is suitably set according to the electrical conductivity etc. which are requested | required of wiring, it shall be about 1-30 micrometers, for example.

  Since the mother board 5 is provided with such an electrical wiring 52, that is, a metal layer, the rigidity of the mother board 5 is improved as compared with the case where the mother board 5 is composed of only the insulating substrate 51. As a result, when the optical waveguide 1 is stacked on the mother board 5, not only the optical waveguide 1 but also the mother board 5 becomes difficult to bend. As a result, the arrangement of the optical waveguide 1 connected to the mother board 5 is maintained with higher accuracy. The Rukoto. Thereby, the transmission / reception efficiency of the signal between the optical waveguide 1 and the mother board 5 can be maintained higher.

  Here, in the opto-electric hybrid board 1000 shown in FIG. 2, the electric element 50 for the electric wiring board is accommodated under the optical waveguide 1. For this reason, when the opto-electric hybrid board 1000 is viewed from above, the electric circuit board electrical element 50 and the core part 14 can coexist in the same region as described above, so the pattern of the core part 14 can be freely set. can do. As a result, for example, the distance between the core portions 14 can be minimized, so that the transmission efficiency of the optical signal can be optimized.

  Further, since the optical waveguide 1 can be easily separated from the mother board 5, repair such as exchanging the optical waveguide 1 and the mother board 5 individually can be easily performed.

  Note that the electric element 50 for the electric wiring board mounted on the mother board 5 is not limited to the above-described one, and for example, IC, CPU, RAM, ROM, transistor, coil, diode, capacitor, vibrator, piezoelectric element, relay, It may be an optical element or the like.

  Here, the distance between the optical waveguide 1 and the motherboard 5 can be easily adjusted, for example, by changing the height of the electrical connector 42 on the photoelectric conversion unit 4 side or the electrical connector 53 on the motherboard 5 side. It is preferable to set to about 1-100 mm, and it is more preferable to set to about 2-80 mm.

  Note that in the opto-electric hybrid board 1000 according to the present embodiment, the electrical connector 42 on the photoelectric conversion unit 4 side and the electrical connector 53 on the motherboard 5 side are connected to each other to fix them. By fixing in this manner, the optical module 100 and the mother board 5 are fixed only partially, so that a large amount of space exists between the optical waveguide 1 and the mother board 5. In this state, for example, the thermal deformation of the mother board 5 hardly affects the optical module 100 side, and the reliability of the opto-electric hybrid board 1000 is improved.

  Further, when the optical module 100 is fixed to the mother board 5, a mechanism other than the electrical connectors 42 and 53, for example, fixing with an adhesive or the like, may be added.

FIG. 12 is a cross-sectional view illustrating another configuration example of the optical module 100 according to the present embodiment.
The photoelectric conversion unit 4 shown in FIG. 12 is obtained by adding a heat spreader 44 to the photoelectric conversion unit 4 shown in FIG. The heat spreader 44 illustrated in FIG. 12 has a box shape that covers the optical element 6 and the photoelectric conversion unit electrical element 7 mounted on the lower surface of the photoelectric conversion unit substrate 41. The bottom surface of the heat spreader 44 and the bottom surface of the photoelectric conversion unit electrical element 7 are in contact with each other. Thereby, the heat from the photoelectric conversion unit electrical element 7 is efficiently transmitted to the heat spreader 44 and diffused. As a result, the heat dissipation of the photoelectric conversion unit electrical element 7 is particularly promoted.

  As a constituent material of the heat spreader 44, a material having high thermal conductivity, for example, a metal material, a carbon material, a ceramic material, or the like is used. In particular, a simple substance or an alloy of copper, aluminum, iron, silver, gold, chromium, nickel, zinc, and tin is preferably used.

  The photoelectric conversion unit electrical element 7 and the heat spreader 44 may be merely in contact with each other, or may be in contact with each other via a heat conductive material. Examples of the heat conducting material include resin materials such as acrylic resins and silicone resins, carbon materials such as graphite, ceramic materials such as silica, alumina, and silicon nitride, metals such as aluminum and copper. A sheet or paste of a system material or the like is used. A composite material sheet or paste in which two or more of these materials are mixed may also be used.

  Further, the heat spreader 44 may be provided with an uneven shape that increases the surface area. As this uneven | corrugated shape, the fin shape etc. which are provided in the lower surface of the heat spreader 44 shown, for example in FIG. 12 are mentioned.

<< Second Embodiment >>
Next, an optical module according to a second embodiment of the opto-electric hybrid board of the present invention will be described.
FIG. 13: is sectional drawing which shows a part of 2nd Embodiment of the opto-electric hybrid board | substrate of this invention.

Hereinafter, although 2nd Embodiment is described, it demonstrates centering around difference with 1st Embodiment, The description is abbreviate | omitted about the same matter. In FIG. 13, the same components as those of the first embodiment are denoted by the same reference numerals as those described above, and detailed description thereof is omitted.
The second embodiment is the same as the first embodiment except that the configuration of the photoelectric conversion unit 4 is different.

  13 includes an insulating substrate 411a provided on the lower surface of the cladding layer 11 of the optical waveguide 1, an insulating substrate 411b provided on the upper surface of the cladding layer 12, and a lower surface of the insulating substrate 411a. An electrical wiring 412a provided on the insulating substrate 411b, a through-wiring 413 penetrating the optical waveguide 1 to connect the electrical wiring 412a and the electrical wiring 412b, and a sealing material 45. And an electrical connector 42, an optical element 6, and a photoelectric conversion unit electrical element 7. Further, the mirror 17 is configured by a part of the inner surface of the recess 170 formed from the electric wiring 412b to the insulating substrate 411b, the optical waveguide 1, and the insulating substrate 411a.

  The structure of the photoelectric conversion unit 4 shown in FIG. 13 is a structure in which the optical waveguide 1 is sandwiched between two insulating substrates 411a and 411b. For this reason, even if a thinner substrate is used as the insulating substrate 411a, the rigidity of the photoelectric conversion unit 4 can be maintained, and the separation distance between the optical element 6 and the mirror 17 can be further shortened. As a result, the optical coupling efficiency between the optical element 6 and the mirror 17 can be further increased.

  The average thickness of the insulating substrates 411a and 411b is preferably about 5 to 50 μm, and more preferably about 10 to 40 μm.

  In the photoelectric conversion unit 4 according to the present embodiment, the photoelectric conversion unit electrical element 7 and the like can be mounted on the upper surface side of the insulating substrate 411b. Is possible.

  Further, since the concave portion 170 is a concave portion opened on the upper surface of the electric wiring 412 b, the concave portion 170 can be formed after the photoelectric conversion portion 4 is bonded to the optical waveguide 1. For this reason, it becomes possible to form the recessed part 170 according to the position of the light receiving / emitting part of the optical element 6, and the optical axis alignment of the light receiving / emitting part and the mirror 17 can be performed very strictly.

«Third embodiment»
Next, a third embodiment of the opto-electric hybrid board according to the present invention will be described.
FIG. 14 is a cross-sectional view showing a part of a third embodiment of the opto-electric hybrid board according to the present invention.

  Hereinafter, the third embodiment will be described, but the description will focus on the differences from the first embodiment, and the description of the same matters will be omitted. In FIG. 14, the same components as those of the above-described embodiments are denoted by the same reference numerals as those described above, and detailed description thereof is omitted.

  In the third embodiment, an electrical interposer (electric wiring board) 55 is interposed between the photoelectric conversion unit 4 and the mother board 5, and the LSI 501 is mounted on the electrical interposer 55. It is the same as the form. In this embodiment, unlike the first and second embodiments, the electric interposer 55 corresponds to an “electric wiring board”.

  The electric interposer 55 shown in FIG. 14 includes a multilayer substrate 550 having a core substrate 551 and a buildup layer 552 laminated on both surfaces thereof, and bumps 553 provided on the lower surface of the multilayer substrate 550. Yes. As described above, the LSI 501 is mounted on the electric interposer 55, and the electrical wiring laid on the surface and inside of the electric interposer 55 and the photoelectric conversion unit 4 are electrically connected via the electric connector 53. It is connected. By using such an electrical interposer 55, it is possible to easily increase the density of electrical wiring and increase the signal transmission speed. As a result, it is possible to increase the speed and capacity of information transmission between the LSI 501 and the photoelectric conversion unit 4, and to maximize the benefits of speeding up by optical communication. That is, the opto-electric hybrid board 1000 that enables high-speed and large-capacity information processing is obtained.

  The electrical interposer 55 is electrically connected to the electrical wiring 52 of the mother board 5 through the bumps 553. Thereby, even when a plurality of electrical interposers 55 are mounted on the mother board 5, these can be linked to each other.

  The multilayer substrate 550 may be a multilayer substrate including a core substrate as shown in FIG. 14, but may be a coreless multilayer substrate not including a core substrate.

  The build-up layer 552 is formed by a build-up method such as an additive method, a semi-additive method, or a subtractive method.

  The electric interposer 55 may be mounted with other electric elements as described above, for example.

  Here, the electric interposer 55 shown in FIG. 14 is a reinforcing member (stiffener) bonded to a region other than the region where the electric element 50 for the electric wiring board such as the LSI 501 is mounted on the upper surface of the multilayer substrate 550. 554. Specifically, in the electrical interposer 55 shown in FIG. 14, a reinforcing member 554 is provided in a region other than the LSI 501 and the electrical connector 53.

  As a constituent material of the reinforcing member 554, a material having a smaller thermal expansion coefficient than the insulating layer of the buildup layer 552 is used. By using such a reinforcing member 554, the thermal expansion of the buildup layer 552 can be suppressed, and the deformation of the multilayer substrate 550 can be suppressed. Specific examples of the constituent material of the reinforcing member 554 include a metal material and a ceramic material, but a metal material is preferably used. Thereby, the heat dissipation of the reinforcement member 554 can be improved and the reliability of the electrical element 50 for electrical wiring boards can be improved.

  In particular, the thermal expansion coefficient of the reinforcing member 554 is preferably 0.5 ppm / ° C. or more and 10 ppm / ° C. or less, more preferably 1 ppm / ° C. or more and 7 ppm / ° C. or less, and 1 ppm / ° C. or more and 5 ppm / ° C. or less. More preferably. Thereby, the deformation of the multilayer substrate 550 can be more effectively prevented.

  The metal material is not particularly limited, and various metal materials can be used. From the viewpoint of realizing heat dissipation and low thermal expansion, it is preferable to use an alloy containing Fe.

  Examples of such Fe-containing alloys include Fe-Ni alloys, Fe-Co-Cr alloys, Fe-Co alloys, Fe-Pt alloys, Fe-Pd alloys, and the like. It is preferable to use a base alloy.

  Such a metal material is useful as a constituent material of the reinforcing member 554 because it has not only excellent heat dissipation but also a low coefficient of thermal expansion.

  The Fe—Ni alloy is not particularly limited as long as it contains Fe and Ni. In addition to Fe and Ni, the balance (M) is a metal such as Co, Ti, Mo, Cr, Pd, and Pt. Of these, one or more metals may be included.

  More specifically, examples of Fe-Ni alloys include Fe-Ni alloys such as Fe-36Ni alloy (Invar), Fe-32Ni-5Co alloy (Super Invar), and Fe-29Ni-17Co alloy (Kovar). Fe-Ni-Co alloys such as Fe-36Ni-12Co alloy (Erin bar), Ni-Mo-Fe alloys such as Fe-Ni-Cr-Ti alloy and Ni-28Mo-2Fe alloy. In addition, Fe-Ni-Co alloys are commercially available under trade names such as KV series (manufactured by NEOMAX Materials) such as KV-2, KV-4, KV-6, KV-15, and KV-25, and Nivarox. ing. Moreover, the Fe-Ni alloy is marketed with brand names, such as NS-5 and D-1 (made by NEOMAX material company), for example. Moreover, the Fe-Ni-Cr-Ti alloy is marketed by brand names, such as Ni-Span C-902 (made by Daido Special Metal), EL-3 (made by NEOMAX material company), for example.

  The Fe—Co—Cr alloy is not particularly limited as long as it contains Fe, Co, and Cr. For example, an Fe—Co—Cr alloy such as Fe-54Co-9.5Cr (stainless invar) is used. Is mentioned. Note that the Fe—Co—Cr-based alloy may contain one or more metals of metals such as Ni, Ti, Mo, Pd, and Pt in addition to Fe, Co, and Cr.

  The Fe—Co alloy is not particularly limited as long as it contains Fe and Co. In addition to Fe and Co, one of metals such as Ni, Ti, Mo, Cr, Pd, and Pt is used. It may contain seeds or two or more metals.

  The Fe—Pt alloy is not particularly limited as long as it contains Fe and Pt. In addition to Fe and Pt, one of metals such as Co, Ni, Ti, Mo, Cr, and Pd is used. It may contain seeds or two or more metals.

  Further, the Fe—Pd alloy is not particularly limited as long as it contains Fe and Pd, and in addition to Fe and Pd, one of metals such as Co, Ni, Ti, Mo, Cr, and Pt. It may contain seeds or two or more metals.

  The reinforcing member 554 is bonded to the upper surface of the multilayer substrate 550. Examples of the bonding method include an adhesive, a pressure-sensitive adhesive, and pressure welding. Among these, the reinforcing member 554 and the multilayer substrate 550 can be easily joined by using an adhesive. Such an adhesive is not particularly limited as long as it has an adhesive function, and various adhesives can be used, but those having excellent thermal conductivity are preferable.

  Examples of the adhesive having excellent thermal conductivity include an adhesive containing an inorganic filler. Examples of the inorganic filler include metals such as Au, Ag, and Pt, oxides such as silica, alumina, diatomaceous earth, titanium oxide, iron oxide, zinc oxide, magnesium oxide, and metal ferrite, boron nitride, silicon nitride, and nitride. Nitrides such as gallium and titanium nitride, hydroxides such as aluminum hydroxide and magnesium hydroxide, carbonates such as calcium carbonate (light and heavy), magnesium carbonate, dolomite, and dawsonite, calcium sulfate, barium sulfate, ammonium sulfate, Sulfates or sulfites such as calcium sulfite, talc, mica, clay, glass fiber, calcium silicate, montmorillonite, bentonite and other silicates, zinc borate, barium metaborate, aluminum borate, calcium borate, boric acid Sodium borate, carbon black, graph Carbon, etc., iron powder, copper powder, aluminum powder, zinc white, molybdenum sulfide, boron fiber, potassium titanate, lead zirconate titanate, one or more of these Is used. In addition, when the thing which has electroconductivity is used as an inorganic filler, an insulation process is performed to the site | part which an adhesive agent contacts as needed.

  Further, the electrical interposer 55 is provided with a reinforcing member 555 having the same configuration as the reinforcing member 554 in a region other than the bump 553 on the lower surface of the multilayer substrate 550. By providing such a reinforcing member 555, the deformation of the electric interposer 55 can be further suppressed.

  The multilayer substrate 550 is provided with a via hole penetrating in the thickness direction, and a heat transfer post 556 is provided in the via hole.

  The heat transfer post 556 passes through the entire multilayer substrate 550 in the thickness direction, and has an upper end exposed at the upper surface of the multilayer substrate 550 and a lower end exposed at the lower surface of the multilayer substrate 550. The heat transfer post 556 has an upper end in contact with the reinforcing member 554 and a lower end in contact with the reinforcing member 555. Thus, the heat transfer post 556 connects the reinforcing member 554 and the reinforcing member 555.

  The heat transfer post 556 has a higher heat transfer property than the multilayer substrate 550 described above. Thereby, heat can be efficiently transferred from the reinforcing member 554 to the reinforcing member 555 through the heat transfer post 556. As a result, the reinforcing members 554 and 555 can improve the performance as a heat spreader.

  Further, since the heat transfer post 556 penetrates the multilayer substrate 550 in the thickness direction, the heat transfer post 556 can be easily and accurately formed in the same manner as a known conductor post.

  Further, the heat transfer post 556 may be hollow or solid. Moreover, it does not specifically limit as a cross-sectional shape of the heat-transfer post 556, For example, circular, an ellipse, a polygon etc. are mentioned. Further, the number of heat transfer posts 556 is not particularly limited and is arbitrary, but it is preferable to increase the number as much as possible so as not to impair the mechanical strength of the multilayer substrate 550.

  The heat transfer post 556 does not contribute to the transmission of an electrical signal. Thereby, heat can be more efficiently transferred from the reinforcing member 554 to the reinforcing member 555 via the heat transfer post 556.

  In the present embodiment, the heat transfer post 556 is provided on the outer peripheral portion when the multilayer substrate 550 is viewed in plan view. Thereby, it is easy to make the temperature distribution of the multilayer substrate 550 uniform.

  Further, the heat transfer post 556 is provided so as not to come into contact with the electric wiring formed on the surface or inside of the multilayer substrate 550. Thereby, a short circuit between the heat transfer post 556 and the electrical wiring can be prevented.

  The constituent material of the heat transfer post 556 is not particularly limited as long as it has higher heat transfer than the multilayer substrate 550, but it is preferable to use a metal material.

  Examples of the metal material include various metals and various alloys such as copper, a copper-based alloy, aluminum, and an aluminum-based alloy. Especially, since it is excellent in heat conductivity, it is preferable to use copper, a copper-type alloy, aluminum, and an aluminum-type alloy. Since copper and a copper-based alloy are excellent in thermal conductivity, the heat dissipation of the electric element for electric wiring board 50 can be further improved.

<< Fourth Embodiment >>
Next, a fourth embodiment of the opto-electric hybrid board according to the present invention will be described.

  FIG. 15A is a cross-sectional view showing a part of the fourth embodiment of the opto-electric hybrid board of the present invention, and FIG. 15B is a top view of FIG.

  Hereinafter, although the fourth embodiment will be described, the description will focus on the differences from the third embodiment, and description of similar matters will be omitted. In FIG. 15, the same components as those of the above-described embodiments are denoted by the same reference numerals as those described above, and detailed description thereof is omitted.

  In the fourth embodiment, the optical waveguide 1 has a shape including a sheet-like portion 1a that extends so as to cover a part of the mother board 5, and a strip-like portion 1b that extends from the sheet-like portion 1a. The third embodiment is the same as the third embodiment except that the belt-like portion 1b is twisted by 90 ° at the connecting portion 1d between the sheet-like portion 1a and the belt-like portion 1b.

  That is, the optical waveguide 1 shown in FIG. 15 has a sheet-like portion 1a that covers the mother board 5 and the electric interposer 55 as in the third embodiment.

  Further, the optical waveguide 1 shown in FIG. 15 has a strip-shaped portion 1b, and the photoelectric conversion portion 4 is provided in the strip-shaped portion 1b. Here, since the band-like portion 1b is twisted by 90 ° at the connecting portion 1d, the arrangement of the photoelectric conversion unit 4 is also rotated by 90 ° with respect to the arrangement of the third embodiment. . As a result, the flat plate-like photoelectric conversion unit 4 is arranged so that the surface direction thereof is orthogonal to the upper surface of the electric interposer 55.

  A plurality of contacts 4120 connected to the electrical wiring 412 are arranged at the end of the insulating substrate 411 of the photoelectric conversion unit 4. By disposing the photoelectric conversion unit 4 as described above, the contact 4120 can be directly inserted into the electrical connector (socket) 53 of the electrical interposer 55. With such a connection structure, it is not necessary to provide the electrical connector 42 in the photoelectric conversion unit 4, and a so-called edge connector in which the contact 4120 is formed instead can be employed. Thereby, cost reduction and simplification of the photoelectric conversion part 4 can be achieved. Further, since the strip-shaped portion 1b is twisted by 90 °, the electrical connector 53 can be directly visually recognized from above the optical waveguide 1, and therefore, the connection work between the contact 4120 and the electrical connector 53 can be easily performed. There is also an advantage of being able to.

  In this case, the electrical connector 53 may be a card socket type connector other than those described above.

  In FIG. 15, the band-shaped portion 1 b is provided at the end of the optical waveguide 1 and the optical connector 101 is attached to the end, but the arrangement of the band-shaped portion 1 b is not limited to this. For example, the belt-like part 1b may be arranged at a position surrounded by the sheet-like part 1a.

  Furthermore, the twist angle in the connection portion 1d is not limited to 90 °, and is appropriately set within a range of about 10 to 90 ° according to the acceptance angle of the electrical connector 53.

«Fifth embodiment»
Next, a fifth embodiment of the opto-electric hybrid board according to the present invention will be described.

  FIG. 16 is an exploded perspective view showing a fifth embodiment of the opto-electric hybrid board of the present invention (partially shown), and FIG. It is XX sectional drawing in FIG.

  Hereinafter, the fifth embodiment will be described, but the description will focus on the differences from the first embodiment, and description of similar matters will be omitted. In FIG. 16, the same components as those of the above-described embodiments are denoted by the same reference numerals as those described above, and detailed description thereof is omitted.

  The fifth embodiment is the same as the first embodiment except that the optical waveguide 1 further includes a metal layer 18.

  The optical waveguide 1 shown in FIGS. 16 and 17 has metal layers 18 provided on the upper surface of the cladding layer 12 and the lower surface of the cladding layer 11, respectively. By providing the metal layer 18, the rigidity of the optical waveguide 1 can be increased. Thereby, when the optical waveguide 1 is overlaid on the mother board 5, the optical waveguide 1 becomes difficult to bend and its shape is easily maintained, so that the arrangement of the optical waveguide 1 and the mother board 5 is maintained with higher accuracy. Thereby, the transmission / reception efficiency of the signal between the optical waveguide 1 and the mother board 5 can be maintained higher. As a result, an opto-electric hybrid board 1000 with particularly high internal signal transmission efficiency (reliability) can be obtained.

(Optical waveguide)
FIG. 18 is an enlarged perspective view of a part of the optical waveguide 1 shown in FIG.

  The optical waveguide 1 shown in FIGS. 17 and 18 has metal layers 18 provided on the upper surface of the cladding layer 12 and the lower surface of the cladding layer 11, respectively. The upper surface of the LSI 501 is in contact (direct contact) with the metal layer 18 provided on the lower surface of the cladding layer 11. As a result, heat from the LSI 501 is easily transferred to the metal layer 18 and diffused. As a result, the heat radiation of the LSI 501 is particularly promoted. That is, the metal layer 18 functions as a heat spreader that dissipates heat from the LSI 501.

  In addition, another heat radiating member (not shown) may be connected to the metal layer 18. Heat from the LSI 501 can be conducted to the heat radiating member through the metal layer 18 to be radiated. As a heat radiating member, a heat radiating fin, a heat exchanger, etc. are mentioned, for example.

  Note that the upper surface of the LSI 501 may be in contact with the metal layer 18 via a heat conductive material. Examples of the heat conducting material include resin materials such as acrylic resins and silicone resins, carbon materials such as graphite, ceramic materials such as silica, alumina, and silicon nitride, metals such as aluminum and copper. A sheet or paste of a system material or the like is used. A composite material sheet or paste in which two or more of these materials are mixed may also be used.

  Moreover, the rigidity of the optical waveguide 1 can be increased by providing the metal layer 18. Thereby, when the optical waveguide 1 is overlaid on the mother board 5, the optical waveguide 1 becomes difficult to bend and its shape is easily maintained, so that the arrangement of the optical waveguide 1 and the mother board 5 is maintained with higher accuracy. Thereby, the transmission / reception efficiency of the signal between the optical waveguide 1 and the mother board 5 can be maintained higher. As a result, an opto-electric hybrid board 1000 with particularly high internal signal transmission efficiency (reliability) can be obtained.

  The average thickness of the metal layer 18 is not particularly limited, but is preferably about 1 to 1000 μm, and more preferably about 3 to 800 μm. Thereby, it is possible to prevent the optical waveguide 1 from being bent due to its own weight while enhancing heat dissipation. That is, when the average thickness of the metal layer 18 is less than the lower limit, sufficient heat dissipation may not be obtained, and sufficient rigidity may not be imparted to the optical waveguide 1. On the other hand, when the average thickness of the metal layer 18 exceeds the upper limit, the mass of the metal layer 18 increases, and the optical waveguide 1 is bent by its own weight, which may reduce the signal transmission efficiency.

  In addition, the total average thickness of the metal layers 18 is preferably about 0.01 to 20 times, more preferably about 0.05 to 15 times the average thickness of the optical waveguide 1. Thereby, it is possible to prevent the mass of the optical waveguide 1 from becoming unnecessarily heavy while ensuring sufficient heat dissipation and rigidity.

  Examples of the constituent material of the metal layer 18 include various metal materials, particularly copper, aluminum, iron, silver, gold, chromium, nickel, zinc, tin, or an alloy containing these metal elements is preferably used. More preferably, aluminum, iron and copper alone or a base alloy thereof is used as a main material. Since these materials have particularly high heat dissipation properties and give the optical waveguide 1 particularly sufficient rigidity, the arrangement of the optical waveguide 1 and the mother board 5 can be maintained with higher accuracy.

  As will be described in detail later, a via hole penetrating the optical waveguide 1 may be provided, and a heat transfer post may be provided there. By connecting the metal layer 18 provided on the upper surface of the clad layer 12 and the metal layer 18 provided on the lower surface of the clad layer 11 through this heat transfer post, the function as a heat spreader is further strengthened. It becomes. Examples of the constituent material of the heat transfer post include various metal materials such as copper, aluminum, nickel, chromium, zinc, tin, gold, silver and the like, or alloys containing these metal elements.

  A through hole is formed in the metal layer 18 provided on the lower surface of the cladding layer 11 at a portion overlapping the optical path. Thereby, it is possible to prevent the propagation of the signal light from being disturbed by the metal layer 18.

  Further, the metal layer 18 may be patterned as necessary to include a portion used as an electrical wiring.

FIG. 19 is a cross-sectional view illustrating another configuration example of the optical module 100 according to the present embodiment.
A photoelectric conversion unit 4 shown in FIG. 19 is obtained by adding a heat spreader (heat radiator) 44 to the photoelectric conversion unit 4 shown in FIG. The heat spreader 44 shown in FIG. 19 has a box shape that covers the optical element 6 and the photoelectric conversion unit electrical element 7 mounted on the lower surface of the photoelectric conversion unit substrate 41. The bottom surface of the heat spreader 44 and the bottom surface of the photoelectric conversion unit electrical element 7 are in contact with each other. Thereby, the heat from the photoelectric conversion unit electrical element 7 is efficiently transmitted to the heat spreader 44 and diffused. As a result, the heat dissipation of the photoelectric conversion unit electrical element 7 is particularly promoted.

  As the constituent material of the heat spreader 44, the same materials as described above are used.

  The photoelectric conversion unit electrical element 7 and the heat spreader 44 may be merely in contact with each other, or may be in contact with each other via a heat conductive material. As the heat conducting material, those described above are used.

  Further, the heat spreader 44 may be provided with an uneven shape that increases the surface area. As this uneven | corrugated shape, the fin shape etc. which are provided in the lower surface of the heat spreader 44 shown, for example in FIG. 19 are mentioned.

<< Sixth Embodiment >>
Next, an optical module according to a sixth embodiment of the opto-electric hybrid board of the present invention will be described.
FIG. 20 is a sectional view showing a part of a sixth embodiment of the opto-electric hybrid board according to the present invention.

Hereinafter, although the sixth embodiment will be described, the differences from the fifth embodiment will be mainly described, and description of similar matters will be omitted. In FIG. 20, the same components as those of the above-described embodiments are denoted by the same reference numerals as those described above, and detailed description thereof is omitted.
The sixth embodiment is the same as the fifth embodiment except that the configuration of the photoelectric conversion unit 4 is different.

  20 includes an insulating substrate 411a provided on the lower surface of the cladding layer 11 of the optical waveguide 1, an insulating substrate 411b provided on the upper surface of the cladding layer 12, and a lower surface of the insulating substrate 411a. An electrical wiring 412a provided on the insulating substrate 411b, a through-wiring 413 penetrating the optical waveguide 1 to connect the electrical wiring 412a and the electrical wiring 412b, and a sealing material 45. And an electrical connector 42, an optical element 6, and a photoelectric conversion unit electrical element 7. Further, the mirror 17 is configured by a part of the inner surface of the recess 170 formed from the electric wiring 412b to the insulating substrate 411b, the optical waveguide 1, and the insulating substrate 411a.

  The structure of the photoelectric conversion unit 4 shown in FIG. 20 is a structure in which the optical waveguide 1 is sandwiched between two insulating substrates 411a and 411b. For this reason, even if a thinner substrate is used as the insulating substrate 411a, the rigidity of the photoelectric conversion unit 4 can be maintained, and the separation distance between the optical element 6 and the mirror 17 can be further shortened. As a result, the optical coupling efficiency between the optical element 6 and the mirror 17 can be further increased.

  The average thickness of the insulating substrates 411a and 411b is preferably about 5 to 50 μm, and more preferably about 10 to 40 μm.

  In the photoelectric conversion unit 4 according to the present embodiment, the photoelectric conversion unit electrical element 7 and the like can be mounted on the upper surface side of the insulating substrate 411b. Is possible.

  Further, since the concave portion 170 is a concave portion opened on the upper surface of the electric wiring 412 b, the concave portion 170 can be formed after the photoelectric conversion portion 4 is bonded to the optical waveguide 1. For this reason, it becomes possible to form the recessed part 170 according to the position of the light receiving / emitting part of the optical element 6, and the optical axis alignment of the light receiving / emitting part and the mirror 17 can be performed very strictly.

FIG. 21 is a cross-sectional view illustrating another configuration example of the optical module 100 according to the present embodiment.
In the photoelectric conversion unit 4 shown in FIG. 21, the insulating substrates 411a and 411b and the electric wirings 412a and 412b of the photoelectric conversion unit 4 shown in FIG. Here, the electric wirings 412a and 412b are each made of a metal material and have the same function as the metal layer 18 according to the first embodiment. For this reason, in the optical module 100 shown in FIG. 21, the rigidity of the optical waveguide 1 is enhanced as a whole, and the optical waveguide 1 is protected from external force, external light, and the external environment.

<< Seventh Embodiment >>
Next, an optical module according to a seventh embodiment of the opto-electric hybrid board of the present invention will be described.
FIG. 22 is a sectional view showing a part of a seventh embodiment of the opto-electric hybrid board according to the present invention.

  Hereinafter, although the seventh embodiment will be described, the description will focus on the differences from the fifth embodiment, and description of similar matters will be omitted. In FIG. 22, the same components as those in the above-described embodiments are denoted by the same reference numerals as those described above, and detailed description thereof is omitted.

  In the optical module 100 according to the seventh embodiment, the insulating substrate 411 of the photoelectric conversion unit 4 and the electric wiring 412 provided on the upper surface thereof, and the metal layer 18 positioned thereon are omitted, while the optical waveguide 1 is the same as the optical module 100 according to the fifth embodiment, except that a through-wiring 18c that penetrates 1 and connects the metal layer 18 and the electric wiring 412 is formed. That is, the photoelectric conversion unit 4 shown in FIG. 22 is configured such that the optical waveguide 1 and the electric wiring 412 are in contact with each other. With such a structure, the distance between the optical element 6 and the mirror 17 can be further shortened as much as the insulating substrate 411 and the like are omitted. As a result, the optical coupling efficiency between the optical element 6 and the mirror 17 can be further increased. Further, since the separation distance can be shortened, the lens 16 can be omitted as shown in FIG.

  In addition, an electric circuit can be constructed in a wider range by patterning the metal layer 18 to create an electric wiring and connecting it to the electric wiring 412 through the through wiring 18c. Furthermore, heat from the optical element 6 and the photoelectric conversion unit electrical element 7 can also be diffused to the metal layer 18 through the through-wiring 18c to dissipate heat.

<< Eighth Embodiment >>
Next, an eighth embodiment of the opto-electric hybrid board according to the present invention will be described.
FIG. 23 is a sectional view showing a part of an eighth embodiment of the opto-electric hybrid board according to the present invention.

  Hereinafter, although the eighth embodiment will be described, the description will focus on the differences from the fifth embodiment, and the description of the same matters will be omitted. In FIG. 23, components similar to those in the above-described embodiments are denoted by the same reference numerals as those described above, and detailed description thereof is omitted.

  In the eighth embodiment, an electrical interposer (electric wiring board) 55 is interposed between the photoelectric conversion unit 4 and the mother board 5, and the LSI 501 is mounted on the electrical interposer 55. It is the same as the form. In this embodiment, unlike the fifth embodiment, the electrical interposer 55 corresponds to an electrical wiring board.

  The electric interposer 55 shown in FIG. 23 includes a multilayer substrate 550 having a core substrate 551 and a buildup layer 552 laminated on both surfaces thereof, and bumps 553 provided on the lower surface of the multilayer substrate 550. Yes. As described above, the LSI 501 is mounted on the electric interposer 55, and the electrical wiring laid on the surface and inside of the electric interposer 55 and the photoelectric conversion unit 4 are electrically connected via the electric connector 53. It is connected. By using such an electrical interposer 55, it is possible to easily increase the density of electrical wiring and increase the signal transmission speed. As a result, it is possible to increase the speed and capacity of information transmission between the LSI 501 and the photoelectric conversion unit 4, and to maximize the benefits of speeding up by optical communication. That is, the opto-electric hybrid board 1000 that enables high-speed and large-capacity information processing is obtained.

  The electrical interposer 55 is electrically connected to the electrical wiring 52 of the mother board 5 through the bumps 553. Thereby, even when a plurality of electrical interposers 55 are mounted on the mother board 5, these can be linked to each other.

  The multilayer substrate 550 may be a multilayer substrate including a core substrate as shown in FIG. 23, or may be a coreless multilayer substrate not including a core substrate.

  The build-up layer 552 is formed by a build-up method such as an additive method, a semi-additive method, or a subtractive method.

  The electric interposer 55 may be mounted with other electric elements as described above, for example.

  Here, the electric interposer 55 shown in FIG. 23 is a reinforcing member (stiffener) bonded to a region other than the region where the electric element 50 for the electric wiring board such as the LSI 501 is mounted on the upper surface of the multilayer substrate 550. 554. Specifically, in the electrical interposer 55 shown in FIG. 23, a reinforcing member 554 is provided in a region other than the LSI 501 and the electrical connector 53.

  As described above, the electrical interposer 55 includes the reinforcing members 554 and 555, that is, the metal layers, and these are connected via the heat transfer posts 556, so that the electrical interposer 55 has the metal layers. Its rigidity is improved compared to the case where it is not provided. Thereby, when the optical waveguide 1 is stacked on the electric interposer 55, not only the optical waveguide 1 but also the electric interposer 55 is difficult to be bent. As a result, the arrangement of the optical waveguide 1 connected to the electric interposer 55 is reduced. It will be maintained with higher accuracy. Thereby, the transmission / reception efficiency of the signal between the optical waveguide 1 and the electric interposer 55 can be maintained higher.

<< Ninth embodiment >>
Next, a ninth embodiment of the opto-electric hybrid board according to the present invention will be described.
FIG. 24A is a cross-sectional view showing a part of the ninth embodiment of the opto-electric hybrid board of the present invention, and FIG. 24B is a top view of FIG.

  Hereinafter, the ninth embodiment will be described, but the description will focus on the differences from the eighth embodiment, and description of similar matters will be omitted. In FIG. 24, the same components as those of the above-described embodiments are denoted by the same reference numerals as those described above, and detailed description thereof is omitted.

  In the ninth embodiment, the optical waveguide 1 has a shape including a sheet-like portion 1a extending so as to cover a part of the mother board 5, and a strip-like portion 1b extending from the sheet-like portion 1a. This is the same as in the eighth embodiment, except that the belt-like portion 1b is twisted by 90 ° at the connecting portion 1d between the sheet-like portion 1a and the belt-like portion 1b.

  That is, the optical waveguide 1 shown in FIG. 24 has a sheet-like portion 1a that covers the mother board 5 and the electric interposer 55 as in the eighth embodiment.

  Further, the optical waveguide 1 shown in FIG. 24 has a strip-shaped portion 1b, and the photoelectric conversion portion 4 is provided in the strip-shaped portion 1b. Here, since the band-like portion 1b is twisted by 90 ° at the connecting portion 1d, the arrangement of the photoelectric conversion unit 4 is also rotated by 90 ° with respect to the arrangement of the fourth embodiment. . As a result, the flat plate-like photoelectric conversion unit 4 is arranged so that the surface direction thereof is orthogonal to the upper surface of the electric interposer 55.

  A plurality of contacts 4120 connected to the electrical wiring 412 are arranged at the end of the insulating substrate 411 of the photoelectric conversion unit 4. By disposing the photoelectric conversion unit 4 as described above, the contact 4120 can be directly inserted into the electrical connector (socket) 53 of the electrical interposer 55. With such a connection structure, it is not necessary to provide the electrical connector 42 in the photoelectric conversion unit 4, and a so-called edge connector in which the contact 4120 is formed instead can be employed. Thereby, cost reduction and simplification of the photoelectric conversion part 4 can be achieved. Further, since the strip-shaped portion 1b is twisted by 90 °, the electrical connector 53 can be directly visually recognized from above the optical waveguide 1, and therefore, the connection work between the contact 4120 and the electrical connector 53 can be easily performed. There is also an advantage of being able to.

  In this case, the electrical connector 53 may be a card socket type connector other than those described above.

  In FIG. 24, the band-shaped portion 1b is provided at the end of the optical waveguide 1, and the optical connector 101 is attached to the end, but the arrangement of the band-shaped portion 1b is not limited to this. For example, the belt-like part 1b may be arranged at a position surrounded by the sheet-like part 1a.

  Furthermore, the twist angle in the connection portion 1d is not limited to 90 °, and is appropriately set within a range of about 10 to 90 ° according to the acceptance angle of the electrical connector 53.

<Method for manufacturing opto-electric hybrid board>
Next, a method for manufacturing the opto-electric hybrid board according to the present invention will be described.

  First, the optical waveguide 1 is manufactured. The optical waveguide 1 is manufactured by laminating the clad layer 11, the core layer 13, and the clad layer 12 in this order. Of these, the core portion 14 and the side clad portion 15 are formed in the core layer 13. For example, a nanoimprint method, a direct drawing method, a direct exposure self-forming method, or the like is used. Also, in the direct drawing method, radiation is irradiated locally toward a film having a refractive index modulation ability capable of forming a refractive index difference between an irradiated region and a non-irradiated region by irradiation of light such as light. The core part 14 and the side clad part 15 are formed by forming the rate difference.

  Examples of the principle of refractive index modulation include monomer diffusion, photobleaching, photoisomerization, photodimerization, and the like, and one or a combination of two or more of these is used. Of these, monomer diffusion is particularly preferably employed as the principle of refractive index modulation. In monomer diffusion, light is partially irradiated to a layer composed of a material in which a photopolymerizable monomer having a refractive index different from that of the polymer is dispersed in the polymer to cause polymerization of the photopolymerizable monomer. Along with this, the photopolymerizable monomer is moved and unevenly distributed to cause the refractive index in the layer to form the core portion 14 and the side cladding portion 15. In the refractive index modulation based on such a principle, the core portion 14 having any shape can be easily formed only by selecting the region to be irradiated with light, so that the optical waveguide 1 can be manufactured very efficiently. it can. Further, since the refractive index distribution formed by such a principle is formed corresponding to the concentration distribution of the photopolymerizable monomer, the refractive index distribution in the cross section of the formed core portion 14 has a smooth refractive index change. Will be accompanied. As a result, the manufactured optical waveguide 1 has a GI-type refractive index distribution, has high transmission characteristics, and can reliably suppress interference at the intersection.

  Examples of a material that causes such monomer diffusion include a photosensitive resin composition described in Japanese Patent Application Laid-Open No. 2010-090328.

  On the other hand, in the case of refractive index modulation based on the principles of photobleaching, photoisomerization, and photodimerization, the amount of change in refractive index can be adjusted according to the amount of irradiated light (radiation amount). In photobleaching, the molecular structure in the material is cleaved by light irradiation, and the leaving group is detached from the main chain. As a result, the refractive index of the material is changed to form the core portion 14. In photoisomerization and photodimerization, light irradiation causes photoisomerization or photodimerization of the material, and the refractive index of the material changes. Thereby, the core part 14 is formed.

  Examples of the material that causes photobleaching include core film materials described in JP-A-2009-145867.

  Examples of materials that cause photoisomerization include norbornene resins described in JP-A-2005-164650.

  Moreover, as a material which produces photodimerization, the photosensitive resin composition etc. which were described in Unexamined-Japanese-Patent No. 2011-105791 are mentioned, for example.

  In addition, by gradually changing the irradiation amount of the light to be irradiated, the formed refractive index distribution is accompanied by a smooth refractive index change. As a method of gradually changing the irradiation amount of the irradiated light, for example, a method using a multi-tone mask such as a gray-tone mask or a half-tone mask, a method of scanning a light beam having a distribution of light intensity, irradiation for each region Examples include a method of irradiating while changing the time.

  Alternatively, the refractive index difference may be formed by diffusing the refractive index adjusting agent in the polymer and continuously changing the concentration of the refractive index adjusting agent. Examples of a method for supplying the refractive index adjusting agent into the polymer include methods such as coating, spraying, adhesion, dipping, and deposition. When supplying the refractive index adjusting agent by such a supply method, an arbitrary refractive index distribution can be formed by adjusting the supply amount for each region. In addition, as a refractive index regulator, what was described in Unexamined-Japanese-Patent No. 2006-276735 is mentioned, for example.

  Further, a mirror 17 is formed on the obtained optical waveguide 1 and a lens 16 is provided. For the formation of the mirror 17, for example, mechanical processing such as dicing processing or transfer of a molding die, laser processing, electron beam processing, or the like is used.

  Next, a metal layer 18 is formed on the lower surface of the cladding layer 11 and the upper surface of the cladding layer 12 as necessary. The method for forming the metal layer 18 is not particularly limited, and examples thereof include physical vapor deposition such as vacuum vapor deposition, chemical vapor deposition such as CVD, plating, and printing.

  Alternatively, the metal layer 18 may be attached to the lower surface of the cladding layer 11 and the upper surface of the cladding layer 12. For this attachment, an adhesive, a pressure-sensitive adhesive, an adhesive sheet, or the like can be used. Alternatively, the metal layer 18 may be formed by depositing a metal material on the lower surface of the cladding layer 11 and the upper surface of the cladding layer 12.

  Next, the optical connector 101 is attached to the end of the optical waveguide 1. Thereby, the optical wiring component 10 is obtained.

  Next, the photoelectric conversion unit 4 is bonded to the lower surface of the optical waveguide 1. Thereby, the optical module 100 is obtained.

On the other hand, an electrical wiring board electrical element 50 such as an LSI 501 is mounted on the insulating substrate 51 to manufacture the mother board 5. Then, the optical waveguide 1 is overlapped so as to cover the mother board 5 and the electric connector 42 of the photoelectric conversion unit 4 and the electric connector 53 of the mother board 5 are connected.
The opto-electric hybrid board 1000 is obtained as described above.

<Electronic equipment>
As described above, the opto-electric hybrid board 1000 of the present invention as described above can shorten and increase the density of the core portion 14 of the optical waveguide 1 and improve the internal optical coupling efficiency. Optical signal transmission efficiency is high. Therefore, by providing the opto-electric hybrid board of the present invention, a highly reliable electronic device (electronic device of the present invention) capable of performing high-quality optical communication can be obtained.

  Examples of the electronic device provided with the opto-electric hybrid board of the present invention include electronic devices such as a mobile phone, a game machine, a router device, a WDM device, a personal computer, a television, and a home server. In any of these electronic devices, it is necessary to transmit a large amount of data at high speed between an arithmetic device such as an LSI and a storage device such as a RAM. Therefore, by providing such an electronic device with the opto-electric hybrid board of the present invention, problems such as noise and signal degradation peculiar to the electrical wiring are eliminated, and a dramatic improvement in performance can be expected.

  In addition, the amount of heat generated in the optical waveguide portion is greatly reduced compared to electrical wiring. For this reason, the electric power required for cooling can be reduced and the power consumption of the whole electronic device can be reduced.

  Moreover, since the opto-electric hybrid board of the present invention can be mounted on the mother board 5 via a connector or the like, it can be easily detached from the mother board 5 as necessary. For this reason, the optical waveguide 1 and the mother board 5 can be taken out individually and replaced or repaired.

  Although the opto-electric hybrid board and the electronic apparatus of the present invention have been described based on the illustrated embodiments, the present invention is not limited to these.

  For example, the optical waveguide 1 may be stacked so as to cover a part of the mother board 5 instead of the entire surface thereof, or may be stacked so as to protrude from the edge of the mother board 5.

  The photoelectric conversion unit substrate 41 included in the photoelectric conversion unit 4 may be a multilayer substrate including a buildup layer.

  Next, examples of the present invention will be described. However, the present invention is not limited to these examples. As long as there is no particular problem, the position, number, quantity, type, etc. may be changed, added, omitted, etc.

1. Production of optical waveguide having refractive index distribution shown in FIG. 5 First, optical waveguides having a linear core part having a refractive index distribution shown in FIG. 5 were produced under different conditions (Examples 1 to 18). The optical waveguides of Comparative Example 1 and Reference Examples 1 to 4 for comparison were also manufactured. The following 3. Then, these optical waveguides were evaluated.

Example 1
(1) Production of Cladding Layer Forming Resin Composition Daicel Chemical Industries, Ltd. Alicyclic Epoxy Resin: Celoxide 2081 20 g, ADEKA Corporation Cationic Polymerization Initiator: Adekaoptomer SP-170 0.6 g , And 80 g of methyl isobutyl ketone were mixed with stirring to prepare a solution.

  Next, the obtained solution was filtered with a 0.2 μm pore size PTFE filter to obtain a clean and colorless and transparent resin composition E1 for forming a cladding layer.

(2) Production of photosensitive resin composition As an epoxy polymer, phenoxy resin manufactured by Nippon Steel Chemical Co., Ltd .: 20 g of YP-50S, 5 g of Celoxide 2021P manufactured by Daicel Chemical Industries, Ltd. as a monomer, and a polymerization initiator Adekaoptomer SP-170 (0.2 g) manufactured by ADEKA Co., Ltd. was charged into 80 g of methyl isobutyl ketone and dissolved by stirring to prepare a solution.

  Next, the obtained solution was filtered through a PTFE filter having a pore size of 0.2 μm to obtain a clean, colorless and transparent photosensitive resin composition F1.

(3) Production of lower clad layer The clad layer-forming resin composition E1 was uniformly applied onto a polyimide film having a thickness of 25 µm by a doctor blade. Thereafter, it was put into a dryer at 50 ° C. for 10 minutes. After completely removing the solvent, the entire surface was irradiated with ultraviolet rays with a UV exposure machine to cure the applied resin composition E1. As a result, a colorless and transparent lower cladding layer having a thickness of 10 μm was obtained. The cumulative amount of ultraviolet light was 500 mJ / cm ² .

(4) Production of core layer On the produced lower clad layer, the photosensitive resin composition F1 was uniformly applied by a doctor blade. Thereafter, it was put into a dryer at 40 ° C. for 5 minutes. After completely removing the solvent to form a film, a photomask having a linear pattern of lines and spaces drawn on the entire surface was pressure-bonded onto the obtained film. Then, ultraviolet rays were irradiated from above the photomask with a parallel exposure machine. The cumulative amount of ultraviolet light was 1000 mJ / cm ² .

  Next, the photomask was removed and placed in an oven at 150 ° C. for 30 minutes. Upon removal from the oven, it was confirmed that a clear waveguide pattern appeared in the coating. Table 1 shows the average width WCO of the core portion and the average width WCL of the side cladding portion. Further, the thickness of the obtained core layer was 50 μm, and the number of core portions was eight.

(5) Production of upper clad layer On the produced core layer, the clad layer forming resin composition E1 was applied in the same manner as in (3) to obtain a colorless and transparent upper clad layer having a thickness of 10 µm. Thus, an optical waveguide was obtained.

(6) Evaluation of refractive index distribution And about the cross section of the core layer of the obtained optical waveguide, the refractive index distribution W of the width direction was acquired with the interference microscope. As a result, the refractive index distribution W had a plurality of low refractive index regions and high refractive index regions, and the refractive index changed continuously.

(Examples 2 to 8)
The composition of the polymer, the composition and content of the monomer, and the cumulative amount of ultraviolet light are set as shown in Table 1, and the average width WCO of the core portion and the average width WCL of the side cladding portions are values shown in Table 1, respectively. The optical waveguides of Examples 2 to 8 were obtained in the same manner as in Example 1 except that the photomask pattern was set as described above.

Example 9
(1) Synthesis of (meth) acrylic polymer 20.0 g of methyl methacrylate (MMA), 30.0 g of benzyl methacrylate (BzMA), and 450 g of methyl isobutyl ketone were charged into a separable flask. These were stirred and mixed, and then replaced with nitrogen gas to prepare a monomer solution.

  On the other hand, 0.25 g of azobisisobutyronitrile as a polymerization initiator was dissolved in 10 g of methyl isobutyl ketone and then replaced with nitrogen gas to prepare an initiator solution.

  And the said initiator solution was added to the said monomer solution using the syringe, stirring the said monomer solution in the state heated at 80 degreeC. The mixture was stirred at 80 ° C. for 1 hour and then cooled to prepare a polymer solution. Thereafter, 5 L of isopropanol was prepared in a beaker, and the polymer solution was dropped into the beaker while stirring at room temperature with a stirrer. After completion of dropping, the mixture was further stirred for 30 minutes, and then the precipitated polymer was taken out and dried at 60 ° C. under reduced pressure for 8 hours in a vacuum dryer. Thereby, acrylic polymer A1 was obtained.

(2) Manufacture of a resin composition for forming a cladding layer Aqueous acrylate resin solution manufactured by Kyoyo Chemical Industry Co., Ltd .: 20 g of RD-180, 20 g of isopropanol, and Carbodilite V-02- manufactured by Nisshinbo Chemical Co., Ltd. as a polymerization initiator A solution was prepared by stirring and mixing 0.4 g of L2.

  Next, the obtained solution was filtered through a PTFE filter having a pore size of 0.2 μm to obtain a clean and colorless and transparent resin composition B1 for forming a cladding layer.

(3) Production of photosensitive resin composition 20 g of synthesized acrylic polymer A1, 5 g of cyclohexyl methacrylate as a monomer, 0.2 g of Irgacure 651 manufactured by BASF Japan Ltd. as a polymerization initiator, in 80 g of methyl isobutyl ketone The solution was added and dissolved by stirring to prepare a solution.

  Subsequently, the obtained solution was filtered with a PTFE filter having a pore size of 0.2 μm to obtain a clean, colorless and transparent photosensitive resin composition C1.

(4) Production of lower clad layer The clad layer-forming resin composition B1 was uniformly applied onto a polyimide film having a thickness of 25 µm by a doctor blade, and then placed in a dryer at 80 ° C for 10 minutes. After completely removing the solvent, it was further put into an oven at 150 ° C. for 10 minutes and cured to obtain a colorless and transparent lower clad layer having a thickness of 10 μm.

(5) Preparation of core layer The photosensitive resin composition C1 was uniformly apply | coated with the doctor blade on the produced lower clad layer. Thereafter, it was put into a dryer at 40 ° C. for 5 minutes. After completely removing the solvent to form a film, a photomask having a linear pattern of lines and spaces drawn on the entire surface was pressure-bonded onto the obtained film. Then, ultraviolet rays were irradiated from above the photomask with a parallel exposure machine. The cumulative amount of ultraviolet light was 800 mJ / cm ² .

  Next, the photomask was removed and placed in an oven at 150 ° C. for 30 minutes. When taken out from the oven, it was confirmed that a clear waveguide pattern having a rectangular cross section appeared on the coating. Table 2 shows the average width WCO of the core portion and the average width WCL of the side cladding portions. Further, the thickness of the obtained core layer was 50 μm, and the number of core portions was eight.

(6) Production of upper clad layer On the produced core layer, the clad layer-forming resin composition B1 was applied in the same manner as in (4) to obtain a colorless and transparent upper clad layer having a thickness of 10 µm. An optical waveguide was obtained in the same manner as above.

(7) Evaluation of refractive index distribution And about the cross section of the core layer of the obtained optical waveguide, the refractive index distribution W of the width direction was acquired with the interference microscope. As a result, the refractive index distribution W had a plurality of low refractive index regions and high refractive index regions, and the refractive index changed continuously.

(Examples 10 to 12)
The composition and content of the monomer, and the cumulative amount of ultraviolet light are set as shown in Table 2, and the photo is taken so that the average width WCO of the core portion and the average width WCL of the side cladding portions are the values shown in Table 2, respectively. Optical waveguides of Examples 10 to 12 were obtained in the same manner as Example 9 except that the mask pattern was set.

(Example 13)
(1) Synthesis of polyolefin-based resin having a leaving group In a glove box filled with dry nitrogen, both moisture and oxygen concentrations are controlled to 1 ppm or less, and 7.2 g (40.1 mmol) of hexylnorbornene (HxNB) , And 12.9 g (40.1 mmol) of diphenylmethylnorbornenemethoxysilane were weighed into a 500 mL vial, and 60 g of dehydrated toluene and 11 g of ethyl acetate were added. The glove box was covered with a silicon sealer and sealed at the top.

  Next, 1.56 g (3.2 mmol) of Ni catalyst and 10 mL of dehydrated toluene were weighed in a 100 mL vial. A stirrer chip was put in, the bottle was sealed, and the catalyst was thoroughly stirred to dissolve completely.

  1 mL of this Ni catalyst solution was accurately weighed with a syringe, and quantitatively injected into the vial in which the two types of norbornene were dissolved, and stirred at room temperature for 1 hour. As a result, a significant increase in viscosity was confirmed. At this point, the stopper was removed, 60 g of tetrahydrofuran (THF) was added, and the mixture was stirred to obtain a reaction solution.

  In a 100 mL beaker, 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (concentration 30%), and 30 g of ion-exchanged water were added and stirred, and an aqueous solution of peracetic acid was prepared on the spot. Next, the total amount of this aqueous solution was added to the above reaction solution and stirred for 12 hours to perform Ni reduction treatment.

  Next, the treated reaction solution was transferred to a separatory funnel, and the lower aqueous layer was removed. Thereafter, 100 mL of a 30% aqueous solution of isopropyl alcohol was added and stirred vigorously. After standing and completely separating two layers, the aqueous layer was removed. This water washing process was repeated three times in total. Thereafter, the oil layer was dropped into a large excess of acetone to reprecipitate the produced polymer, and the filtrate was separated from the filtrate. Then, polymer # 1 was obtained by performing heat drying for 12 hours in the vacuum dryer set to 60 degreeC. The molecular weight distribution of the polymer # 1 was Mw = 100,000 and Mn = 40,000 by GPC measurement. The molar ratio of each structural unit in polymer # 1 was 50 mol% for the hexylnorbornene structural unit and 50 mol% for the diphenylmethylnorbornenemethoxysilane structural unit, as determined by NMR.

(2) Production of composition for forming core layer 10 g of the above-mentioned polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of an antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyloxetane monomer ( Toa Gosei CHOX, CAS # 483303-3-25-9, molecular weight 186, boiling point 125 ° C./1.33 kPa) 2 g, and polymerization initiator (photoacid generator) Rhodorsil Photoinitiator 2074 (Rhodia, CAS # 178233-72-2) ) (0.0125 g in 0.1 mL of ethyl acetate) was added and dissolved uniformly. Then, it filtered with a 0.2 micrometer PTFE filter, and obtained the composition for clean core layer formation. In addition, this composition differs from the photosensitive resin composition as described in each Example by the point in which a monomer is not contained. On the other hand, the polymer # 1 has a function of releasing a leaving group upon irradiation with actinic radiation, and a so-called photobleaching phenomenon occurs. The polymerization initiator is expressed as PI 2074 in Table 3.

(3) Manufacture of the composition for forming a clad layer The molar ratio of each structural unit of the purified polymer # 1 was changed to hexyl norbornene structural unit 80 mol% and diphenylmethylnorbornene methoxysilane structural unit 20 mol%, A clad layer forming composition was obtained in the same manner as the core layer forming composition except that the polymer # 1 was used instead.

(4) Production of lower clad layer The clad layer forming composition was uniformly applied onto a polyimide film having a thickness of 25 µm by a doctor blade. Thereafter, it was put into a dryer at 50 ° C. for 10 minutes. After completely removing the solvent, the entire surface was irradiated with UV light by a UV exposure machine to cure the applied composition. As a result, a colorless and transparent lower cladding layer having a thickness of 10 μm was obtained. The cumulative amount of ultraviolet light was 500 mJ / cm ² .

(5) Preparation of core layer The core layer resin composition was uniformly apply | coated with the doctor blade on the produced lower clad layer. Thereafter, it was put into a dryer at 40 ° C. for 5 minutes. After completely removing the solvent to form a film, a photomask having a linear pattern of lines and spaces drawn on the entire surface was pressure-bonded onto the obtained film. Then, ultraviolet rays were irradiated from above the photomask with a parallel exposure machine. The integrated light quantity of ultraviolet rays was 1300 mJ / cm ² .

  Next, the photomask was removed and placed in an oven at 150 ° C. for 30 minutes. When taken out from the oven, it was confirmed that a clear waveguide pattern having a rectangular cross section appeared on the coating. The thickness of the obtained core layer was 50 μm. The number of core portions was eight.

(6) Production of upper clad layer On the produced core layer, the clad layer-forming resin composition E1 was applied in the same manner as in (3) to obtain a colorless and transparent upper clad layer having a thickness of 10 µm. An optical waveguide was obtained as described above.

(7) Evaluation of refractive index distribution And about the cross section of the core layer of the obtained optical waveguide, the refractive index distribution W of the width direction was acquired with the interference microscope. As a result, the refractive index distribution W had a plurality of low refractive index regions and high refractive index regions, and the refractive index changed continuously.

(Examples 14 and 15)
The composition and content of the monomer, and the cumulative amount of UV light are set as shown in Table 3, and the average width WCO of the core portion and the average width WCL of the side cladding portions are set to values shown in Table 3, respectively. An optical waveguide was obtained in the same manner as in Example 13 except that the mask pattern was set.

(Example 16)
(1) Production of optical waveguide Using the composition for forming an optical waveguide used in Example 13, a multi-color extrusion molding (coextrusion molding) was performed on a polyethersulfone (PES) film by a die coater. As a result, a multicolor molded body was obtained in which three layers were extruded with the composition for forming the core layer as an intermediate layer and the composition for forming the clad layer as a lower layer and an upper layer. This was put into a dryer at 55 ° C. for 10 minutes to completely remove the solvent. Thereafter, a photomask was pressed and selectively irradiated with ultraviolet rays at 1300 mJ / cm ² . The mask was removed, and heating was performed at 150 ° C. for 1.5 hours in a dryer. After heating, a clear waveguide pattern appeared, and it was confirmed that a core part and a side cladding part were formed. Thereafter, a length of 10 cm was cut out from the obtained optical waveguide. Note that the formed optical waveguide has eight core portions formed in parallel. The total thickness of the optical waveguide was 100 μm.

(2) Evaluation of refractive index distribution And about the cross section of the core layer of the obtained optical waveguide, the refractive index distribution W of the width direction was acquired with the interference microscope. As a result, the refractive index distribution W had a plurality of low refractive index regions and high refractive index regions, and the refractive index changed continuously.

  On the other hand, regarding the cross section of the optical waveguide, a refractive index distribution T in the thickness direction was obtained by an interference microscope along a center line passing through the center of the width of the core portion in the vertical direction. As a result, the refractive index distribution T had a region where the refractive index continuously changed at the center thereof, and a region having a refractive index lower than that of the region and a substantially constant value on both sides thereof. . That is, the refractive index distribution T in the thickness direction of the obtained optical waveguide was a so-called graded index type.

(Examples 17 and 18)
The composition and content of the monomer and the integrated light quantity of ultraviolet rays are set as shown in Table 3, and the photomask is set so that the average width WCO of the core portion and the average width WCL of the side cladding portions are values shown in Table 3, respectively. The optical waveguides of Examples 17 and 18 were obtained in the same manner as Example 16 except that the above pattern was set.

(Comparative Example 1)
An optical waveguide of Comparative Example 1 was obtained in the same manner as Example 13 except that CHO was not added and the amount of PI2074 added was 0.01 g for the core forming composition and the cladding forming composition.

  In the obtained optical waveguide, the refractive index of the core part was constant, the refractive index of the side cladding part was also constant, and the refractive index of the core part and the cladding part was discontinuous. That is, the refractive index distribution of the core layer of the obtained optical waveguide was a so-called step index (SI) type distribution.

(Reference Examples 1 and 2)
Except that the pattern of the photomask was changed so that the average width WCO of the core portion and the average width WCL of the side cladding portions were values shown in Table 1, respectively, in the same manner as in Examples 1 and 2, The optical waveguides of Examples 1 and 2 were obtained.

(Reference Examples 3 and 4)
Except that the pattern of the photomask was changed so that the average width WCO of the core portion and the average width WCL of the side cladding portions were values shown in Table 2, respectively, in the same manner as in Examples 9 and 10, respectively. The optical waveguides of Examples 3 and 4 were obtained.

  Tables 1, 2, and 3 show the manufacturing conditions of the optical waveguides obtained in the above Examples, Comparative Examples, and Reference Examples.

2. 2. Production of Optical Waveguide Having Refractive Index Distribution Shown in FIG. 6 First, an optical waveguide having a linear core portion having a refractive index distribution shown in FIG. Then we evaluated it.

(Examples 19 to 37, Comparative Example 2 and Reference Examples 5 to 10)
The manufacturing conditions were changed as shown in Tables 4, 5, and 6, and the drying conditions at the time of forming the core layer in Examples 19 to 31 and Reference Examples 5 to 8 were set to 50 ° C. × 10 minutes. Optical waveguides were obtained in the same manner as in Example 1 except that the drying conditions for forming the core layer in Comparative Example 2 and Reference Examples 9 and 10 were changed to 60 ° C. × 15 minutes. Moreover, in Examples 35-37, after obtaining the multicolor molded object by coextrusion molding similar to Example 16, it was made to irradiate with an ultraviolet-ray.

3. 3.1 Evaluation of Optical Waveguide 3.1 Refractive Index Distribution of Optical Waveguide With respect to the cross section of the core layer of the obtained optical waveguide, the refractive index distribution is measured with an interference microscope along the center line in the thickness direction, A refractive index profile in the width direction of the surface was obtained. In addition, since the obtained refractive index distribution has the same refractive index distribution pattern repeated for every core part, a part was cut out from the obtained refractive index distribution, and this was made into the refractive index distribution W. Similarly, a refractive index distribution T was obtained.

  Of the refractive index distribution W, the shape of the distribution designated as “GI type” in Tables 1, 2 and 3 is a high refractive index region WH including a maximum value Wm and a low refractive index region WL as shown in FIG. It was a shape in which and were arranged alternately.

  Further, in the refractive index distribution W, the distribution shape of “W type” in Tables 4, 5 and 6 has four minimum values and five maximum values alternately arranged as shown in FIG. It was a shape. From this W-type refractive index distribution W, each minimum value Ws1, Ws2, Ws3 and Ws4 and each maximum value Wm1, Wm2, Wm3, Wm4 and Wm5 were obtained, and an average refractive index WA in the cladding part was obtained. The refractive index distribution W in the width direction of the optical waveguide obtained in each example and each reference example had a continuous change in the refractive index in the whole.

  Further, in this W-type refractive index distribution W, the width a [μm] of the portion where the refractive index in the vicinity of the maximum values Wm2 and Wm4 formed in the core portion is equal to or greater than the average refractive index WA, and The width b [μm] of the portion where the refractive index in the vicinity of each local minimum value Ws1, Ws2, Ws3 and Ws4 has a value less than the average refractive index WA was measured.

In each optical waveguide, the maximum change rate of the refractive index in the gradually decreasing portion was in the range of 0.008 to 0.025. Moreover, all the maximum values of the refractive index of the intersection were higher than the maximum value Wm, and the difference was within the range of 0.003 to 0.015.
The above measurement results are shown in Tables 7-13.

  The refractive index distribution W in the width direction of the optical waveguide obtained in Comparative Examples 1 and 2 was a step index type.

3.2 Transmission loss of optical waveguide Light emitted from an 850 nm VCSEL (surface emitting laser) is introduced into the optical waveguide obtained in each example and each comparative example via an optical fiber of 50 μmφ, and emitted light is 200 μmφ. The light was received by an optical fiber and the light intensity was measured. Note that the cutback method was used to measure the transmission loss. Then, when the measured values were plotted with the longitudinal direction of the optical waveguide taken on the horizontal axis and the insertion loss on the vertical axis, the measured values were arranged on a straight line. Therefore, the transmission loss was calculated from the slope of the straight line. The results are shown in Tables 14 to 19 below.

3.3 Retention of pulse signal waveform A pulse signal with a pulse width of 1 ns was incident on the obtained optical waveguide from a laser pulse light source, and the pulse width of the emitted light was measured.

  And about the measured pulse width of the emitted light, in Tables 14-16, the measured value of the optical waveguide obtained in Comparative Example 1 is set to 1, and in Tables 17-19, the measured value of the optical waveguide obtained in Comparative Example 2 is set. The relative value when set to 1 was calculated, and this was evaluated according to the following evaluation criteria. The results are shown in Tables 14 to 19 below.

<Evaluation criteria for pulse width>
A: Relative value of pulse width is less than 0.5 B: Relative value of pulse width is 0.5 or more and less than 0.8 Δ: Relative value of pulse width is 0.8 or more and less than 1 ×: The relative value of the pulse width is 1 or more

  As is apparent from Tables 14 to 19, it is recognized that the transmission loss and the blunting of the pulse signal are suppressed in the optical waveguides obtained in the respective examples as compared with the optical waveguides obtained in the respective comparative examples. It was.

  In addition, about the composition for core layer formation in which the photo bleaching phenomenon used in the comparative example 1 can be adjusted, the amount of modulation of the refractive index can be adjusted according to the amount of irradiation light. An attempt was made to form the refractive index profile W using a photomask set to change. When the refractive index distribution was evaluated as described above for the obtained optical waveguide, a high refractive index region and a low refractive index region were confirmed, but the change in refractive index was not as continuous as in each example. . In addition, the obtained optical waveguide had a larger transmission loss than the respective examples, and the retention of the pulse signal waveform was also low.

4). Manufacture of Optical Waveguide Having Intersection Next, an optical waveguide having an intersection was manufactured as follows under the same conditions as in the above-described Examples, Comparative Examples, and Reference Examples.

(Example A)
An optical waveguide having crossed portions is manufactured by manufacturing an optical waveguide in the same manner as in Example 1 except that a photomask used for producing the core layer is one corresponding to the pattern of the optical waveguide having crossed portions. Manufactured. In the manufacture of the optical waveguide, three types of optical waveguides having intersection angles of 30 °, 60 °, and 90 ° at each intersection were manufactured.

(Examples B to Z, a to k, Comparative Examples A and B, and Reference Examples A to J)
Except for using a photomask that corresponds to the pattern of the core portion having the intersection as the photomask used when producing the core layer, the same as in Examples 2 to 37, Comparative Examples 1 and 2, and Reference Examples 1 to 10 By manufacturing the optical waveguide, optical waveguides each having an intersecting portion were manufactured. In the manufacture of the optical waveguide, three types of optical waveguides having intersection angles of 30 °, 60 °, and 90 ° at each intersection were manufactured.

5. Evaluation of Optical Waveguide Having Intersection Next, the insertion loss between both ends of the obtained optical waveguide having the crossing portion was measured. The calculated transmission losses at the intersection are shown in Tables 14-19. As a result, the insertion loss value showed the same tendency as the transmission loss described above. That is, the optical waveguides having the intersections obtained in each example had a sufficiently small insertion loss, whereas the optical waveguides having the intersections obtained in each comparative example had a relatively large insertion loss. And 3. It was confirmed that the smaller the transmission loss measured in (3), the smaller the amount of signal light that interferes.

  Further, when the transmission loss at the intersection is calculated, the optical waveguide having the intersection obtained in each example has a smaller transmission loss at the intersection than the optical waveguide having the intersection obtained in each comparative example. Became clear. When the intersection angle was 90 °, the transmission loss was 0.02 dB or less.

  The method for calculating the transmission loss at the intersection is a method in which a plurality of samples having different numbers of intersections are prepared and the transmission loss per intersection is calculated from the comparison of the insertion loss.

  Further, the amount of signal light interfering with the core portion intersecting with the core portion to be measured (hereinafter referred to as “interference light amount”) was measured. And about the measured light amount of interference, in Tables 14-16, the measured value of the optical waveguide obtained by the comparative example 1 was set to 1, and in Tables 17-19, the measured value of the optical waveguide obtained by the comparative example 2 was set to 1. Relative values were calculated and shown in Tables 14-19.

  As a result, it was confirmed that by optimizing the refractive index distribution W, the amount of interfering signal light is reduced.

  From the above, it has been clarified that loss and interference can be suppressed in an optical waveguide having a core portion whose refractive index distribution is a continuous distribution that satisfies a specific condition.

DESCRIPTION OF SYMBOLS 1 Optical waveguide 1a Sheet-shaped part 1b Band-shaped part 1c Notch 1d Connection part 10 Optical wiring component 100 Optical module 1000 Opto-electric hybrid board 101 Optical connector 1011 Connector main body 1012 Leg part 1013 Connector lid body 11, 12 Cladding layer 13 Core Layer 14 Core part 141, 142 Core part 147, 148 Crossing part 15 Side cladding part 151, 152, 153 Side cladding part 16 Lens 17 Mirror 170 Recess 18 Metal layer 18c Through wiring 2 Support film 3 Cover film 4 Photoelectric conversion part 41 Photoelectric Conversion unit substrate 411, 411a, 411b Insulating substrate 412, 412a, 412b Electrical wiring 4120 Contact 413 Through wiring 414 Through hole 42 Electrical connector 44 Heat spreader 45 Sealing material 5 Motherboard 50 Electric element for electric wiring board 501 LSI
502 Capacitor 503 Chip Resistor 51 Insulating Board 52 Electrical Wiring 53 Electrical Connector 55 Electrical Interposer 550 Multilayer Board 551 Core Board 552 Build-up Layer 553 Bump 554, 555 Reinforcement Member 556 Heat Transfer Post 6 Optical Element 60 Element Main Body 61 Light Emitting / Receiving Light Part 62 Terminal 7 Electric element for photoelectric conversion part 70 Element body 72 Terminal C1 Center line W Refractive index distribution

Claims (12)

An electrical wiring board comprising: a first substrate; electrical wiring laid on or on the surface of the first substrate; and an electrical element mounted on the first substrate;
A plurality of core portions provided so as to intersect with each other on the same plane, and a side clad portion provided adjacent to a side surface of each core portion, from the central portion of the core portion toward the side clad portion A core layer in which a refractive index distribution in which the refractive index continuously decreases, an optical path conversion unit that converts an optical path of the core unit, a metal layer provided on at least one surface side of the core layer, A film-shaped optical waveguide comprising:
Have
Between the optical waveguide and the electrical wiring board, configured to transmit and receive signals with photoelectric conversion,
The optical waveguide is disposed on the opposite side of the first substrate across the electrical element ,
The opto-electric hybrid board according to claim 1, wherein the metal layer is in direct contact with the electric element or in contact with a heat conducting part .   The opto-electric hybrid board according to claim 1, wherein the optical waveguide is detachably attached to the electric wiring board. The opto-electric hybrid board further includes a photoelectric conversion unit including a second substrate, an electrical wiring laid on or inside the second substrate, and an optical element mounted on the second substrate. Have
The optical path included in the optical waveguide is optically connected to the optical element included in the photoelectric conversion unit, the electrical wiring included in the photoelectric conversion unit, and the electrical wiring included in the electrical wiring substrate; The opto-electric hybrid board according to claim 1 or 2, wherein are electrically connected.   The opto-electric hybrid board according to claim 3, wherein the electrical wiring of the photoelectric conversion unit and the electrical wiring of the electrical wiring board are electrically connected via an electrical connector.   5. The photoelectric hybrid substrate according to claim 3, wherein the photoelectric conversion unit further includes a heat dissipating body provided so as to be in contact with the optical element. The opto-electric hybrid board according to any one of claims 1 to 5, wherein the constituent material of the metal layer is mainly composed of aluminum, iron and copper alone or a base alloy thereof. The optical waveguide, the opto-electric hybrid board according to any one of claims 1 and is arranged such that a space occurs 6 between the first substrate of the electric wiring board. With the motherboard,
An electrical interposer mounted on the motherboard as the electrical wiring board;
The optical waveguide;
With
The optical waveguide, so as to cover the electrical element in which the electrical interposer comprises, according to any one of claims 1 is disposed on the opposite side of the first substrate via the electric element 7 Opto-electric hybrid board. The electrical wiring board includes a metal layer provided on each side of the first substrate, and a via post provided so as to connect the metal layers through the first substrate. Item 9. The opto-electric hybrid board according to Item 8 . The electric wiring board, the opto-electric hybrid board according to the any one of the first claims 1 comprises a metal layer provided on at least one surface side of the substrate 9. The opto-electric hybrid board according to any one of claims 1 to 10 , comprising the optical waveguide and an optical connector provided at an end of the core portion. An electronic apparatus comprising the optical-electric hybrid board according to any one of claims 1 to 11.

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