Photoelectric hybrid substrate, optical module, and electronic apparatus

Abstract

To provide a photoelectric hybrid substrate, an optical module, and an electronic apparatus that can manage heat generated in a conductive layer.SOLUTION: A photoelectric hybrid substrate 1 comprises an optical waveguide film 2 that extends along a longitudinal direction, and a flexible circuit board 3 that extends along the longitudinal direction and is arranged on one side in a thickness direction of the optical waveguide film 2. The optical waveguide film 2 includes an under cladding layer 21 and a core layer 22 in order from one side toward the other side of the thickness direction. The flexible circuit board 3 includes a base insulating layer 12 and a conductive layer 13 from the other side toward one side of the thickness direction. The conductive layer 13 has flat wiring 25 that extends along the longitudinal direction. The length W1 in a width direction of the flat wiring 25 and the length H1 in the thickness direction satisfy H1 / W1≤0.15. The interval S1 between a surface on one side in the thickness direction of the core layer 22 and a surface on one side of the thickness direction of the base insulating layer 12 satisfies S1≥3 μm.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an optoelectronic hybrid board, an optical module, and an electronic device. [Background technology]

[0002] Conventionally, an optoelectronic hybrid board has been known. The optoelectronic hybrid board includes, for example, an optical waveguide and an electric circuit board. For example, an optoelectronic conversion element and a driving element are mounted on the optoelectronic hybrid board. Meanwhile, the driving element may generate heat during operation, and the heat generated in the driving element may be transferred to the optoelectronic conversion element, resulting in a deterioration in the function of the optoelectronic conversion element. For this reason, heat management is required for the optoelectronic hybrid board.

[0003] Therefore, for example, the following opto-electrical hybrid board has been proposed. That is, the opto-electrical hybrid board includes an optical waveguide and an electric circuit board. The electric circuit board includes terminals for mounting optical elements and terminals for electrically connecting to a printed wiring board on which drive elements are mounted (see, for example, Patent Document 1 below).

[0004] That is, if the printed wiring board on which the drive elements are mounted and the opto-electric hybrid board on which the optical elements are mounted are separate bodies, it is possible to prevent heat generated in the drive elements from being transmitted to the photoelectric conversion elements. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-113887 Summary of the Invention [Problem to be solved by the invention]

[0006] On the other hand, depending on the field of use of the optoelectronic hybrid board, further heat management is required. In particular, optoelectronic hybrid boards that comply with the MIPI (Mobile Industry Processor Interface) standard require management of heat generated in the conductor layers.

[0007] The present invention provides an optoelectronic hybrid board, an optical module, and an electronic device that are capable of managing heat generated in a conductor layer. [Means for solving the problem]

[0008] The present invention [1] includes an optoelectronic hybrid substrate comprising an optical waveguide layer extending along the longitudinal direction, and a wiring circuit board extending along the longitudinal direction and disposed on one side of the optical waveguide layer in a thickness direction, wherein the optical waveguide layer comprises an underclad layer and a core layer, in that order from one side to the other in the thickness direction, and the wiring circuit board comprises a base insulating layer and a conductor layer, in that order from the other side to the one side in the thickness direction, and the conductor layer has flat wiring extending along the longitudinal direction, wherein a length W1 in the width direction of the flat wiring and a length H1 in the thickness direction of the flat wiring satisfy the following formula (1), and a distance S1 between a surface on one side in the thickness direction of the core layer and a surface on one side in the thickness direction of the base insulating layer satisfies the following formula (2).

[0009] H1 / W1≦ 0.15 (1) S1≧ 3μm (2)

[0010] In the above-mentioned optoelectronic hybrid board, the conductor layer has flat wiring that satisfies the above formula (1). Such flat wiring is less likely to accumulate heat than non-flat wiring that does not satisfy the above formula (1). Furthermore, in the above-mentioned optoelectronic hybrid board, the distance between the conductor layer and the core layer satisfies the above formula (2), so that heat generated in the conductor layer is less likely to be transmitted to the core layer.

[0011] Therefore, the optoelectronic hybrid board can prevent heat generated in the conductor layer from being transferred to the core layer, ie, the optoelectronic hybrid board can manage heat in the conductor layer.

[0012] The present invention [2] includes the optoelectronic hybrid substrate described in [1] above, in which the conductor layer has non-flat wiring extending along the longitudinal direction, and the length W2 of the non-flat wiring in the width direction and the length H2 of the non-flat wiring in the thickness direction satisfy the following formula (3).

[0013] In the above-mentioned optoelectronic hybrid board, flat wires are less likely to accumulate heat than non-flat wires, so as long as the optoelectronic hybrid board includes at least one flat wire, it can also include a non-flat wire.

[0014] The present invention [3] includes the optoelectronic hybrid substrate described in [2] above, in which, for at least one of the non-flat wirings, at least a portion of the projection surface in the thickness direction of the non-flat wiring does not overlap with the projection surface in the thickness direction of the core layer.

[0015] In the above-mentioned photoelectric hybrid board, the non-flat wiring is more likely to accumulate heat than the flat wiring, and in such a case, unless at least a part of the projection surface in the thickness direction of the non-flat wiring overlaps with the projection surface in the thickness direction of the core layer, heat is less likely to be transferred to the core layer.

[0016] Therefore, the optoelectronic hybrid board can prevent heat generated in the conductor layer from being transferred to the core layer.

[0017] The present invention [4] includes the optoelectronic hybrid substrate described in [3] above, in which, for at least one of the non-flat wirings, the entire projection surface in the thickness direction of the non-flat wiring does not overlap with the projection surface in the thickness direction of the core layer.

[0018] In the above-mentioned photoelectric hybrid board, the non-flat wiring is more likely to accumulate heat than the flat wiring. In such a case, if the projection surface of the non-flat wiring in the thickness direction does not entirely overlap the projection surface of the core layer in the thickness direction, heat is even less likely to be transmitted to the core layer.

[0019] Therefore, the above-described optoelectronic hybrid board can further suppress the heat generated in the conductor layer from being transmitted to the core layer.

[0020] The present invention [5] includes an optoelectronic hybrid substrate according to any one of the above [2] to [4], in which a part of the projection surface in the thickness direction of the flat wiring overlaps with the projection surface in the thickness direction of the core layer.

[0021] In the above-mentioned photoelectric hybrid board, the flat wiring is less likely to accumulate heat than the non-flat wiring, and therefore, when the projection surface of the flat wiring in the thickness direction overlaps the projection surface of the core layer in the thickness direction, heat is less likely to be transferred to the core layer than when the projection surface of the non-flat wiring in the thickness direction overlaps the projection surface of the core layer in the thickness direction.

[0022] Furthermore, when a portion of the projection surface in the thickness direction of the flat wiring overlaps with the projection surface in the thickness direction of the core layer, heat is less likely to be transmitted to the core layer than when the entire projection surface in the thickness direction of the flat wiring overlaps with the projection surface in the thickness direction of the core layer.

[0023] Therefore, the above-described optoelectronic hybrid board can further suppress the heat generated in the conductor layer from being transmitted to the core layer.

[0024] The present invention [6] includes the optoelectronic hybrid board according to any one of the above [1] to [5], wherein the wired circuit board includes a metal supporting board.

[0025] In the above-mentioned optoelectronic hybrid board, the metal supporting board has relatively excellent heat dissipation properties, so if the optoelectronic hybrid board includes a metal supporting board, heat can be dissipated efficiently.

[0026] Therefore, the optoelectronic hybrid board can prevent heat generated in the conductor layer from being transferred to the core layer.

[0027] The present invention [7] includes the optoelectronic hybrid board according to any one of the above [1] to [6], further comprising a heat dissipation member, the heat dissipation member being in contact with the wiring circuit board and / or the optical waveguide layer.

[0028] In the above-mentioned optoelectronic hybrid board, if the heat dissipation member is in contact with the wiring circuit board and / or the optical waveguide layer, heat can be dissipated efficiently.

[0029] Therefore, with the above-described optoelectronic hybrid board, it is possible to more efficiently prevent the heat generated in the conductor layer from being transmitted to the core layer.

[0030] The present invention [8] includes the optoelectronic hybrid substrate according to any one of [1] to [7] above, wherein the undercladding layer has a glass transition temperature of 50°C or higher, and the core layer has a glass transition temperature of 50°C or higher.

[0031] In the above optoelectronic hybrid substrate, if the glass transition temperature of the undercladding layer is equal to or higher than a predetermined value and the glass transition temperature of the core layer is equal to or higher than a predetermined value, the optical waveguide layer has excellent heat resistance.

[0032] The present invention [9] includes an optical module comprising the optoelectronic hybrid board according to any one of the above [1] to [8] and an optoelectronic conversion element mounted on the optoelectronic hybrid board.

[0033] The optical module includes the optoelectronic hybrid board, and therefore can prevent heat generated in the conductor layer from being transferred to the core layer.

[0034] The present invention

[10] includes an electronic device comprising the optical module described in [9] above.

[0035] The electronic device includes the optical module, and therefore can prevent heat generated in the conductor layer from being transferred to the core layer.

[0036] The present invention

[11] further comprises a housing for accommodating the optical module, the housing being in contact with the wiring circuit board and / or the optical waveguide layer of the optical module. The electronic device according to the above

[10] .

[0037] In the optical module described above, if the housing is in contact with the wiring circuit board and / or the optical waveguide layer, heat can be dissipated efficiently.

[0038] Therefore, according to the electronic device, the heat generated in the conductor layer can be more efficiently prevented from being transferred to the core layer. [Effects of the Invention]

[0039] The optoelectronic hybrid board, optical module, and electronic device of the present invention can prevent heat generated in the conductor layer from being transferred to the core layer. That is, the optoelectronic hybrid board, optical module, and electronic device described above can manage heat in the conductor layer. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is a schematic plan view of an embodiment of the optoelectronic hybrid board of the present invention. [Figure 2] 2A is a cross-sectional view of the optoelectronic hybrid board shown in FIG. 1 taken along line AA, and FIG. 2B is a cross-sectional view of the optoelectronic hybrid board shown in FIG. 1 taken along line BB. [Figure 3] FIG. 3A is a cross-sectional view taken along line AA in another embodiment of the optoelectronic hybrid board of the present invention, and FIG. 3B is a cross-sectional view taken along line BB in another embodiment of the optoelectronic hybrid board of the present invention. [Figure 4] FIG. 4 is a schematic diagram showing a heat dissipation sheet provided on the optoelectronic hybrid board. [Figure 5] FIG. 5 is a schematic diagram showing a housing that houses the optoelectronic hybrid board. DETAILED DESCRIPTION OF THE INVENTION

[0041] 1. Optoelectronic hybrid board 1) Overall structure Hereinafter, one embodiment of the optoelectronic hybrid board of the present invention will be described with reference to FIG. 1 and FIGS. 2A and 2B.

[0042] 1, the optoelectronic hybrid board 1 has a long, flat band shape extending along the longitudinal direction. The optoelectronic hybrid board 1 is a member used for transmitting optical signals (hereinafter referred to as optical transmission), and more specifically, is a flexible member for optical transmission that complies with, for example, the MIPI (Mobile Industry Processor Interface) standard.

[0043] The optoelectronic hybrid substrate 1 has a plurality of terminal portions and is electrically connected to two external substrates 100. More specifically, one longitudinal end of the optoelectronic hybrid substrate 1 is electrically connected to a first external substrate 101 (see imaginary line) serving as the external substrate 100. Furthermore, the other longitudinal end of the optoelectronic hybrid substrate 1 is electrically connected to a second external substrate 102 (see imaginary line) serving as the external substrate 100.

[0044] The optoelectronic hybrid board 1 is also capable of mounting a photoelectric conversion element 200. More specifically, a light emitting element 201 and a light receiving element 202 as the photoelectric conversion element 200 are mounted on the optoelectronic hybrid board 1.

[0045] The light-emitting element 201 is a photoelectric conversion element 200 that converts an electrical signal into an optical signal, and is, for example, a vertical cavity surface-emitting light-emitting diode (VCSEL). In Fig. 1, two light-emitting elements 201 are mounted on the photoelectric hybrid substrate 1, more specifically, a first light-emitting element 201A and a second light-emitting element 201B are mounted.

[0046] The first light-emitting element 201A is mounted to convert an electrical signal output from the first external substrate 101 into an optical signal and output the optical signal. The first light-emitting element 201A is mounted near the first external substrate 101 on one side of the optoelectronic hybrid substrate 1 in the longitudinal direction.

[0047] The second light-emitting element 201B is mounted to convert an electrical signal output from the second external substrate 102 into an optical signal and output the optical signal. The second light-emitting element 201B is mounted near the second external substrate 102 on the other longitudinal side of the optoelectronic hybrid substrate 1.

[0048] The light receiving element 202 is a photoelectric conversion element 200 that converts an optical signal into an electrical signal, and is, for example, a photodiode (PD). In Fig. 1, two light receiving elements 202 are mounted on the optoelectronic hybrid substrate 1, more specifically, a first light receiving element 202A and a second light receiving element 202B are mounted.

[0049] The first light receiving element 202A is mounted to convert the optical signal output from the first light emitting element 201A into an electrical signal and output the electrical signal. The first light receiving element 202A is mounted near the second external substrate 102 on the other longitudinal side of the optoelectronic hybrid substrate 1. The second light emitting element 201B and the first light receiving element 202A are arranged in parallel and spaced apart in the width direction (i.e., the direction perpendicular to both the longitudinal direction and the thickness direction).

[0050] The second light receiving element 202B is mounted to convert the optical signal output from the second light emitting element 201B into an electrical signal and output the electrical signal. The second light receiving element 202B is mounted near the first external substrate 101 on one longitudinal side of the optoelectronic hybrid substrate 1. The first light emitting element 201A and the second light receiving element 202B are arranged in parallel with a gap in the width direction.

[0051] Such an optoelectronic hybrid board 1 includes an optical waveguide film 2 as an optical waveguide layer and a flexible circuit board 3 as a wiring circuit board to enable optical transmission between a first external board 101 and a second external board 102. Each of these will be described in detail below.

[0052] 2) Optical waveguide film 2A and 2B, the optical waveguide film 2 has a flat band shape extending in the longitudinal direction. The optical waveguide film 2 is disposed from one end to the other end in the longitudinal direction of the optoelectronic hybrid substrate 1. The optical waveguide film 2 is also disposed from one end to the other end in the width direction of the optoelectronic hybrid substrate 1.

[0053] The optical waveguide film 2 includes an undercladding layer 21, a core layer 22, and an overcladding layer 23, which are arranged in this order from one side to the other in the thickness direction.

[0054] The undercladding layer 21 has a flat band shape extending along the longitudinal direction. The undercladding layer 21 is disposed so as to be in contact with the surface on the other side in the thickness direction of the flexible circuit board 3 (described later).

[0055] The undercladding layer 21 is made of, for example, a resin. Examples of the resin include a photosensitive resin. Examples of the photosensitive resin include an epoxy resin, an acrylic resin, and a silicone resin, and preferably an epoxy resin. The resin of the undercladding layer 21 is preferably selected so that the refractive index of the undercladding layer 21 is lower than the refractive index of the core layer 22. The specific refractive index of the undercladding layer 21 is selected depending on the purpose and application.

[0056] From the viewpoint of heat resistance, the glass transition temperature of the undercladding layer 21 is, for example, 50° C. or higher, preferably 70° C. or higher, and more preferably 85° C. or higher. The glass transition temperature is calculated as the peak value of tan δ obtained in dynamic viscoelasticity measurement in shear mode at a frequency of 1 Hz and a heating rate of 5° C. / min (the same applies hereinafter).

[0057] The thickness of the undercladding layer 21 is, for example, 2 μm or more and 200 μm or less, preferably 3 μm or more and 100 μm or less, more preferably 4 μm or more and 75 μm or less, and even more preferably 5 μm or more and 50 μm or less.

[0058] The core layer 22 has a rectangular columnar shape extending in the longitudinal direction. The core layer 22 has a generally rectangular cross-sectional shape. A plurality of core layers 22 (four in FIG. 1) are arranged at intervals in the width direction on the surface on the other side in the thickness direction of the undercladding layer 21.

[0059] The core layer 22 is made of, for example, a resin. Examples of the resin include the above-mentioned photosensitive resins, and preferably, an epoxy resin. The resin of the core layer 22 is preferably selected so that the refractive index of the core layer 22 is higher than the refractive index of the undercladding layer 21 and the refractive index of the overcladding layer 23. The specific refractive index of the core layer 22 is selected depending on the purpose and application.

[0060] From the viewpoint of heat resistance, the glass transition temperature of the core layer 22 is, for example, 50° C. or higher, preferably 70° C. or higher, and more preferably 85° C. or higher.

[0061] The thickness of the core layer 22 is, for example, 5 μm or more and 100 μm or less, preferably 10 μm or more and 90 μm or less, more preferably 15 μm or more and 80 μm or less, and even more preferably 20 μm or more and 60 μm or less.

[0062] In a plan view, the overcladding layer 23 is disposed at the same position as the undercladding layer 21. Specifically, the overcladding layer 23 is disposed on the surface on the other side in the thickness direction of the undercladding layer 21 so as to cover the other surface in the thickness direction and the side surface of the core layer 22.

[0063] The over-cladding layer 23 is made of, for example, a resin. Examples of the resin include the above-mentioned photosensitive resins, and preferably, an epoxy resin. The resin of the over-cladding layer 23 is preferably selected so that the refractive index of the over-cladding layer 23 is lower than the refractive index of the core layer 22.

[0064] The resin of the overcladding layer 23 is preferably the same as the resin of the undercladding layer 21. The refractive index of the overcladding layer 23 is preferably the same as the refractive index of the undercladding layer. The glass transition temperature of the overcladding layer 23 is preferably the same as the glass transition temperature of the undercladding layer.

[0065] The thickness of the overcladding layer 23 is, for example, 2 μm or more and 600 μm or less, preferably 3 μm or more and 100 μm or less, more preferably 4 μm or more and 60 μm or less, and even more preferably 5 μm or more and 45 μm or less.

[0066] The thickness of the over cladding layer 23 is the distance between the other surface in the thickness direction of the under cladding layer 21 and the other surface in the thickness direction of the over cladding layer 23. The ratio of the thickness of the over cladding layer 23 to the thickness of the under cladding layer 21 is, for example, 0.25 or more and 10 or less, or preferably 0.75 or more and 3 or less.

[0067] 2A, the optical waveguide film 2 includes a plurality of mirrors 24. More specifically, the mirrors 24 include a light-emitting side mirror 24A corresponding to the light-emitting element 201 and a light-receiving side mirror 24B corresponding to the light-receiving element 202.

[0068] The light-emitting side mirror 24A is formed by cutting the core layer 22 at a predetermined angle (for example, 45°). The light-emitting side mirror 24A faces, in the thickness direction, a light inlet / outlet (not shown) for the light emitting element 201. The light-emitting side mirror 24A also faces, in the thickness direction, a light-emitting side through-hole 15A of the metal supporting board 11, which will be described later.

[0069] The light-receiving side mirror 24B is formed by cutting the core layer 22 at a predetermined angle (for example, 45°). The light-receiving side mirror 24B faces, in the thickness direction, a light inlet / outlet (not shown) for the light-receiving element 202. The light-receiving side mirror 24B also faces, in the thickness direction, a light-receiving side through-hole 15B of the metal supporting board 11, which will be described later.

[0070] The method for forming the optical waveguide film 2 is not particularly limited. For example, by a known method, an undercladding layer 21, a core layer 22, and an overcladding layer 23 are sequentially laminated on the surface on the other side in the thickness direction of a metal supporting board 11 (described later). Next, by a known method, an emitter-side mirror 24A and a receiver-side mirror 24B are formed. By this method, the optical waveguide film 2 is formed on the surface on the other side in the thickness direction of a flexible circuit board 3 (described later).

[0071] The thickness of the optical waveguide film 2 is not particularly limited and may be set appropriately. The thickness of the optical waveguide film 2 is, for example, 20 μm or more and 250 μm or less, or preferably 50 μm or more and 150 μm or less.

[0072] 3) Wired circuit board 2A and 2B, the flexible circuit board 3 has a flat band shape extending in the longitudinal direction. The flexible circuit board 3 is disposed from one end to the other end in the longitudinal direction of the optoelectronic hybrid substrate 1. The flexible circuit board 3 is also disposed from one end to the other end in the width direction of the optoelectronic hybrid substrate 1.

[0073] Furthermore, the flexible circuit board 3 is arranged on one side of the optical waveguide film 2 in the thickness direction, and more specifically, the flexible circuit board 3 is arranged so as to be in contact with the entire surface of the one side of the optical waveguide film 2 in the thickness direction.

[0074] The flexible circuit board 3 includes a metal supporting board 11, an insulating base layer 12, a conductor layer 13, and an insulating cover layer 14, arranged in this order from the other side to the one side in the thickness direction.

[0075] The metal supporting board 11 has a flat band shape extending along the longitudinal direction. The metal supporting board 11 is disposed on one side in the thickness direction of the optical waveguide film 2. More specifically, the metal supporting board 11 is disposed in contact with one side in the thickness direction of the undercladding layer 21 without an adhesive layer therebetween.

[0076] The metal supporting board 11 is made of, for example, a metal. Examples of metals include 42 alloy, aluminum, copper-beryllium, phosphor bronze, copper, silver, and aluminum. From the viewpoint of ensuring excellent rigidity and toughness, stainless steel is preferable.

[0077] 2A , the metal supporting board 11 has a plurality of through holes 15. More specifically, the through holes 15 have light-emitting side through holes 15A corresponding to the light-emitting elements 201 and light-receiving side through holes 15B corresponding to the light-receiving elements 202.

[0078] The light-emitting side through hole 15A is formed by drilling through the metal supporting board 11 using a known method. The light-emitting side through hole 15A faces a light inlet / outlet (not shown) of the light-emitting element 201 in the thickness direction. The light-emitting side through hole 15A also faces a light-emitting side mirror 24A of the optical waveguide film 2 in the thickness direction.

[0079] The light-receiving-side through hole 15B is formed by drilling through the metal supporting board 11 using a known method. The light-receiving-side through hole 15B faces, in the thickness direction, a light inlet / outlet (not shown) of the light-receiving element 202. The light-receiving-side through hole 15B also faces, in the thickness direction, a light-receiving-side mirror 24B of the optical waveguide film 2.

[0080] The thickness of the metal supporting board 11 is selected within a range that does not impair the flexibility of the flexible circuit board 3. The thickness of the metal supporting board 11 is, for example, 3 μm or more and 100 μm or less, or preferably 10 μm or more and 50 μm or less.

[0081] The insulating base layer 12 has a flat band shape extending in the longitudinal direction. The insulating base layer 12 is disposed on one side in the thickness direction of the metal supporting board 11. That is, the insulating base layer 12 is laminated on the metal supporting board 11 so as to be in contact with the surface of the metal supporting board 11 on one side in the thickness direction.

[0082] The insulating base layer 12 is made of, for example, an insulating material such as polyimide, and the thickness of the insulating base layer 12 is set appropriately.

[0083] 2A, the insulating base layer 12 has a plurality of openings 16. More specifically, the openings 16 have a light-emitting side opening 16A corresponding to the light-emitting element 201 and a light-receiving side opening 16B corresponding to the light-receiving element 202.

[0084] The light-emitting side opening 16A is formed by photolithography of the insulating base layer 12 using a known method. The light-emitting side opening 16A faces a light inlet / outlet (not shown) of the light-emitting element 201 in the thickness direction. The light-emitting side opening 16A also faces a light-emitting side mirror 24A of the optical waveguide film 2 in the thickness direction.

[0085] The light-receiving side opening 16B is formed by photolithography of the insulating base layer 12 using a known method. The light-receiving side opening 16B faces, in the thickness direction, a light inlet / outlet (not shown) of the light-receiving element 202. The light-receiving side opening 16B also faces, in the thickness direction, a light-receiving side mirror 24B of the optical waveguide film 2.

[0086] The conductor layer 13 is disposed on one side in the thickness direction of the insulating base layer 12. That is, the conductor layer 13 is laminated on the insulating base layer 12 so as to be in contact with the surface of the insulating base layer 12 on one side in the thickness direction.

[0087] The conductor layer 13 is made of, for example, a conductor material such as copper, and the thickness of the conductor layer 13 is set appropriately.

[0088] The conductor layer 13 includes a wiring portion 17 extending along the longitudinal direction and a terminal portion 27 continuous with the wiring portion 17 .

[0089] As shown in FIG. 1, the wiring section 17 includes an optical-electrical transmission wiring 18 and an electrical transmission wiring 19.

[0090] The optical-electrical transmission wiring 18 is a wiring that can transmit an electrical signal converted into an optical signal. The optical-electrical transmission wiring 18 is disposed between the first external substrate 101 and the second external substrate 102, and can be connected to the external substrates 100 (i.e., the first external substrate 101 and the second external substrate 102) and the photoelectric conversion element 200 (i.e., the light-emitting element 201 and the light-receiving element 202).

[0091] 1, the opto-electrical hybrid board 1 includes four optical-electrical transmission lines 18. Hereinafter, the four optical-electrical transmission lines 18 will be distinguished as an optical-electrical transmission line 18a, an optical-electrical transmission line 18b, an optical-electrical transmission line 18c, and an optical-electrical transmission line 18d.

[0092] The optical-electrical transmission wiring 18a is arranged so as to enable electrical connection between the first external substrate 101 and the first light-emitting element 201A when the external substrate 100 and the photoelectric conversion element 200 are mounted. In other words, the optical-electrical transmission wiring 18a enables an electrical signal output from the first external substrate 101 to be input to the first light-emitting element 201A.

[0093] The optical-electrical transmission wiring 18b is arranged so as to enable electrical connection between the second external substrate 102 and the first light-receiving element 202A when the external substrate 100 and the photoelectric conversion element 200 are mounted. In other words, the optical-electrical transmission wiring 18b enables an electrical signal output from the first light-receiving element 202A to be input to the second external substrate 102.

[0094] The optical-electrical transmission wiring 18c is arranged so as to enable electrical connection between the second external substrate 102 and the second light-emitting element 201B when the external substrate 100 and the photoelectric conversion element 200 are mounted. In other words, the optical-electrical transmission wiring 18c enables an electrical signal output from the second external substrate 102 to be input to the second light-emitting element 201B.

[0095] The optical-electrical transmission wiring 18d is arranged so as to enable electrical connection between the first external substrate 101 and the second light-receiving element 202B when the external substrate 100 and the photoelectric conversion element 200 are mounted. In other words, the optical-electrical transmission wiring 18d enables an electrical signal output from the second light-receiving element 202B to be input to the first external substrate 101.

[0096] The electrical transmission wiring 19 is connected to the first external substrate 101 and the second external substrate 102 to enable the transmission of power and / or the transmission of electrical signals directly (i.e., without conversion to optical signals) between the first external substrate 101 and the second external substrate 102.

[0097] More specifically, in FIG. 1, the optoelectronic hybrid board 1 includes four electrical transmission lines 19.

[0098] At approximately the center in the width direction of the optoelectronic hybrid substrate 1, two electrical transmission wirings 19 are formed in a linear pattern along the longitudinal direction of the optoelectronic hybrid substrate 1. Hereinafter, the electrical transmission wirings 19 formed in a linear pattern will be referred to as linear wirings 19A. The two linear wirings 19A are arranged so as to enable electrical connection between the first external substrate 101 and the second external substrate 102 when the external substrate 100 and the photoelectric conversion element 200 are mounted.

[0099] On both sides of the optoelectronic hybrid substrate 1 in the width direction, two electrical transmission wirings 19 are routed so as to bypass the light emitting element 201 and the light receiving element 202. Hereinafter, the electrical transmission wirings 19 that bypass the light emitting element 201 and the light receiving element 202 will be referred to as bypass wirings 19B. The bypass wirings 19B are arranged so as to enable electrical connection between the first external substrate 101 and the second external substrate 102 when the external substrate 100 and the photoelectric conversion element 200 are mounted.

[0100] The terminal portions 27 are junctions between the conductor layer 13 and the external substrate 100 and the photoelectric conversion element 200. The terminal portions 27 are formed at both ends of the wiring portion 17 in the longitudinal direction.

[0101] More specifically, the terminal portions 27 are formed at both longitudinal ends of the optical-electrical transmission wiring 18 and are exposed from the cover insulating layer 14 (described later). The optical-electrical transmission wiring 18 is electrically connected to the external substrate 100 and the photoelectric conversion element 200 via the terminal portions 27.

[0102] Terminal portions 27 are formed on both longitudinal ends of electrical transmission wiring 19 and are exposed from cover insulating layer 14 (described later). Electrical transmission wiring 19 and external substrate 100 are electrically connected via terminal portions 27.

[0103] 2A and 2B, the insulating cover layer 14 has a flat band shape extending in the longitudinal direction. The insulating cover layer 14 is disposed on one side in the thickness direction of the conductor layer 13. In other words, the insulating cover layer 14 is laminated so as to contact the surface of the conductor layer 13 on one side in the thickness direction.

[0104] More specifically, the cover insulating layer 14 is in contact with one surface in the thickness direction of the base insulating layer 12 around the wiring portion 17 so as to cover the wiring portion 17 .

[0105] The insulating cover layer 14 is made of, for example, an insulating material such as polyimide, and the thickness of the insulating cover layer 14 is set appropriately.

[0106] The thickness of the flexible circuit board 3 is not particularly limited and may be set appropriately. The thickness of the flexible circuit board 3 is, for example, 10 μm or more and 150 μm or less, or preferably 15 μm or more and 100 μm or less.

[0107] 4) Electrical and optical transmission In the above-described optoelectronic hybrid board 1, any information is transmitted between the first external board 101 and the second external board 102 as an electrical signal and an optical signal.

[0108] More specifically, any information is output as an electrical signal from the first external substrate 101 and input to the first light emitting element 201A via the optical-electrical transmission wiring 18a.

[0109] In the first light-emitting element 201A, the above electrical signal is converted into an optical signal, which is output from the first light-emitting element 201A and input to the second light-receiving element 202B via the light-emitting side mirror 24A, the core layer 22, and the light-receiving side mirror 24B (see dashed line in Figure 2B).

[0110] In the second light receiving element 202B, the optical signal is converted into an electrical signal, and the electrical signal is output from the second light receiving element 202B and input to the second external substrate 102 via the optical-electrical transmission wiring 18b.

[0111] That is, any information is transmitted from the first external board 101 to the second external board 102 as an electrical signal and an optical signal.

[0112] In the same manner as described above, any information is transmitted as an electrical signal and an optical signal from the second external substrate 102 to the first external substrate 101. That is, an electrical signal is output from the second external substrate 102, the electrical signal is converted into an optical signal in the second light-emitting element 201B, the optical signal is transmitted via the core layer 22, the optical signal is converted into an electrical signal in the second light-receiving element 202B, and the optical signal is input to the first external substrate 101.

[0113] Furthermore, in the above-described optoelectronic hybrid board 1, power and / or electrical signals are transmitted between the first external board 101 and the second external board .

[0114] That is, in the above-described photoelectric hybrid board 1, for example, power is output from the first external board 101 and input to the second external board 102 via the electrical transmission wiring 19. In addition, power can also be output from the second external board 102 and input to the first external board 101 via the electrical transmission wiring 19.

[0115] Furthermore, in the above-described optoelectronic hybrid board 1, for example, an electrical signal is output from the first external board 101 and input to the second external board 102 via the electrical transmission wiring 19. Furthermore, an electrical signal can also be output from the second external board 102 and input to the first external board 101 via the electrical transmission wiring 19.

[0116] 5) Heat management In the above-described optoelectronic hybrid board 1, the shape of the wiring portion 17 is designed from the viewpoint of heat management.

[0117] More specifically, in the above-described optoelectronic hybrid substrate 1, power and / or electrical signals are transmitted via the electrical transmission wiring 19. Also, in the above-described optoelectronic hybrid substrate 1, optical signals are transmitted via the core layer 22 of the optical waveguide film 2.

[0118] 2A, power and / or electrical signals and optical signals are transmitted in parallel in the longitudinal direction in the region between the light-emitting element 201 and the light-receiving element 202. Hereinafter, the region between the light-emitting element 201 and the light-receiving element 202 will be referred to as the optical-electrical transmission region.

[0119] In such a case, the transmission of power and / or electrical signals may cause heat accumulation in electrical transmission wiring 19. When heat accumulation occurs in electrical transmission wiring 19, core layer 22 of optical waveguide film 2 may be heated, causing deformation or a decrease in physical properties (refractive index). In other words, the heat from electrical transmission wiring 19 may cause problems in the transmission of optical signals.

[0120] Therefore, in the above-described optoelectronic hybrid board 1, heat of the electrical transmission wiring 19 is managed as follows.

[0121] More specifically, in the above-described optoelectronic hybrid substrate 1, the electrical transmission wiring 19 is formed in a flat shape in the optoelectronic transmission region (i.e., the region between the light emitting element 201 and the light receiving element 202). That is, the conductor layer 13 has flat wiring 25.

[0122] As shown in Figures 1 and 2A, the flat wiring 25 is part of the detour wiring 19B, extends along the longitudinal direction, and is arranged in the optical-electrical transmission area (i.e., the area between the light-emitting element 201 and the light-receiving element 202).

[0123] 1 and 2B, the flat wires 25 have a relatively flat, generally rectangular cross-sectional shape compared to the non-flat wires 26 described later. The length W1 of the flat wires 25 in the width direction and the length H1 of the flat wires 25 in the thickness direction satisfy the following formula (1).

[0124] H1 / W1≦ 0.15 (1)

[0125] The length W1 of the flat wire 25 in the width direction is, for example, 100 μm or more and 10,000 μm or less, preferably 200 μm or more and 7,500 μm or less, and more preferably 500 μm or more and 5,000 μm or less.

[0126] The length H1 of the flat wire 25 in the thickness direction is, for example, 1 μm or more and 50 μm or less, preferably 2 μm or more and 30 μm or less, and more preferably 5 μm or more and 15 μm or less.

[0127] The ratio of the length H1 in the thickness direction of the flat wire 25 to the length W1 in the width direction of the flat wire 25 is 0.15 or less. The ratio of the length H1 in the thickness direction of the flat wire 25 to the length W1 in the width direction of the flat wire 25 is preferably 0.05 or less, and more preferably 0.01 or less. The ratio of the length H1 in the thickness direction of the flat wire 25 to the length W1 in the width direction of the flat wire 25 is, for example, 0.001 or more.

[0128] That is, the ratio of the length H1 in the thickness direction of the flat wire 25 to the length W1 in the width direction of the flat wire 25 is, for example, 0.001 or more and 0.15 or less, preferably 0.001 or more and 0.05 or less, and more preferably 0.001 or more and 0.001 or less.

[0129] The flat wires 25 have superior heat dissipation properties and are less likely to accumulate heat than the non-flat wires 26 described below. Therefore, the flat wires 25 can suppress heat accumulation and suppress deformation and deterioration of the physical properties of the core layer 22. In other words, if the electrical transmission wires 19 include the flat wires 25, the heat of the electrical transmission wires 19 can be efficiently managed.

[0130] On the other hand, in the above-described optoelectronic hybrid board 1, if the wiring section 17 is formed in a flat shape as a whole, a large space is required, which may cause the optoelectronic hybrid board 1 to become large.

[0131] Therefore, in the above-described optoelectronic hybrid board 1, in order to manage the heat of the electrical transmission wiring 19 and to save space, the straight wiring 19A of the electrical transmission wiring 19 is formed in a non-flat shape. Also, the detour wiring 19B of the electrical transmission wiring 19 is formed in a non-flat shape in an area other than the optoelectronic transmission area (i.e., the area between the light emitting element 201 and the light receiving element 202). That is, the electrical transmission wiring 19 has non-flat wiring 26.

[0132] 2A, the non-flat wiring 26 is the entire straight wiring 19A and the remainder of the aforementioned part of the detour wiring 19B. The non-flat wiring 26 extends in the longitudinal direction and is arranged in an area other than the photoelectric transmission area (i.e., the area between the light-emitting element 201 and the light-receiving element 202).

[0133] 1 and 2B, the non-flat wiring 26 has a generally rectangular cross-sectional shape that is relatively less flat than the above-described flat wiring 25. A length W1 of the non-flat wiring 26 in the width direction and a length H1 of the non-flat wiring 26 in the thickness direction satisfy the following formula (3).

[0134] H1 / W1> 0.15 (3)

[0135] The length W1 of the non-flat wire 26 in the width direction is, for example, 100 μm or more and 10,000 μm or less, preferably 200 μm or more and 7,500 μm or less, and more preferably 500 μm or more and 5,000 μm or less.

[0136] The length H1 of the non-flat wire 26 in the thickness direction is, for example, 1 μm or more and 50 μm or less, preferably 2 μm or more and 30 μm or less, and more preferably 5 μm or more and 15 μm or less.

[0137] The ratio of the length H1 in the thickness direction of the non-flat wiring 26 to the length W1 in the width direction of the non-flat wiring 26 exceeds 0.15. The ratio of the length H1 in the thickness direction of the non-flat wiring 26 to the length W1 in the width direction of the non-flat wiring 26 is preferably 0.2 or more, and more preferably 0.5 or more. The ratio of the length H1 in the thickness direction of the non-flat wiring 26 to the length W1 in the width direction of the non-flat wiring 26 is, for example, 2.0 or less, and preferably 1.5 or less.

[0138] That is, the ratio of the length H1 in the thickness direction of the non-flat wiring 26 to the length W1 in the width direction of the non-flat wiring 26 is, for example, greater than 0.15 and not more than 2.0, preferably not less than 0.2 and not more than 1.5, and more preferably not less than 0.5 and not more than 1.5.

[0139] The non-flat wiring 26 has excellent space-saving properties compared to the flat wiring 25. Therefore, if the wiring section 17 includes both the flat wiring 25 and the non-flat wiring 26, it is possible to manage the heat of the electrical transmission wiring 19 and also to achieve space saving.

[0140] Furthermore, in the above-described optoelectronic hybrid board 1, the relative arrangement of the conductor layer 13 and the optical waveguide film 2 is designed from the viewpoint of heat management.

[0141] 2B, the distance S1 between one surface of the core layer 22 in the thickness direction and one surface of the insulating base layer 12 in the thickness direction satisfies the following formula (2): The distance S1 is the shortest distance in the thickness direction of the optoelectronic hybrid substrate 1.

[0142] S1≧ 3μm (2)

[0143] That is, from the viewpoint of heat management, the lower limit of the distance S1 between one surface in the thickness direction of the core layer 22 and one surface in the thickness direction of the base insulating layer 12 is, for example, 3 μm or more, preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 25 μm or more. Also, from the viewpoint of space saving, the distance S1 between one surface in the thickness direction of the core layer 22 and one surface in the thickness direction of the base insulating layer 12 is, for example, 300 μm or less, preferably 150 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

[0144] That is, the distance S1 between one thickness-wise surface of the core layer 22 and one thickness-wise surface of the base insulating layer 12 is, for example, 3 μm or more and 300 μm or less, preferably 10 μm or more and 150 μm or less, more preferably 15 μm or more and 100 μm or less, and even more preferably 25 μm or more and 50 μm or less.

[0145] In the above-mentioned photoelectric hybrid substrate 1, if the distance between the conductor layer 13 and the core layer 22 satisfies the above formula (2), the conductor layer 13 and the core layer 22 are separated from each other, and therefore, in particular, heat generated in the conductor layer 13 is less likely to be transmitted to the core layer 22.

[0146] Therefore, the optoelectronic hybrid board 1 can prevent the heat generated in the conductor layer 13 from being transmitted to the core layer 22. That is, the optoelectronic hybrid board 1 can manage the heat of the conductor layer 13.

[0147] Furthermore, from the viewpoint of thermal management, in the above-mentioned photoelectric hybrid substrate 1, as shown in Figure 2B, in at least one of the non-flat wirings 26, at least a portion of the projection surface in the thickness direction of the non-flat wiring 26 does not overlap with the projection surface in the thickness direction of the core layer 22.

[0148] Preferably, from the viewpoint of heat management, in the above-mentioned photoelectric hybrid board 1, for all non-flat wirings 26, at least a portion of the projection surface in the thickness direction of the non-flat wirings 26 does not overlap with the projection surface in the thickness direction of the core layer 22.

[0149] Furthermore, from the viewpoint of thermal management, in the above-mentioned photoelectric hybrid substrate 1, for at least one of the non-flat wirings 26, the entire projection surface of the non-flat wiring 26 in the thickness direction does not overlap with the projection surface of the core layer 22 in the thickness direction.

[0150] Particularly preferably, in the above-described photoelectric hybrid board 1, the entire projection surface of all the non-flat wirings 26 in the thickness direction does not overlap the projection surface of the core layer 22 in the thickness direction.

[0151] In other words, it is particularly preferable that the non-flat wiring 26 and the core layer 22 are not disposed opposite each other in the thickness direction.

[0152] That is, in the above-described optoelectronic hybrid substrate 1, the non-flat wiring 26 is more likely to accumulate heat than the flat wiring 25. In such a case, if the non-flat wiring 26 and the core layer 22 are arranged opposite each other in the thickness direction, the heat generated in the non-flat wiring 26 is more likely to be transferred to the core layer 22. In contrast, if the non-flat wiring 26 and the core layer 22 are not arranged opposite each other in the thickness direction, the heat generated in the non-flat wiring 26 is less likely to be transferred to the core layer 22.

[0153] Therefore, according to the above-described photoelectric hybrid board 1, the heat generated in the non-flat wiring 26 can be prevented from being transmitted to the core layer 22.

[0154] On the other hand, from the viewpoint of space saving, in the above-described photoelectric hybrid board 1, a part of the projection surface of the flat wires 25 in the thickness direction overlaps with the projection surface of the core layer 22 in the thickness direction.

[0155] That is, as described above, if the non-flat wires 26 and the core layer 22 are not disposed opposite each other in the thickness direction, the heat generated in the non-flat wires 26 can be prevented from being transmitted to the core layer 22.

[0156] Similarly, if the flat wires 25 and the core layer 22 are not disposed opposite to each other in the thickness direction, the heat generated in the flat wires 25 can be prevented from being transmitted to the core layer 22.

[0157] However, if the flat wiring 25 and the core layer 22 are not arranged opposite each other in the thickness direction, and the non-flat wiring 26 and the core layer 22 are not arranged opposite each other in the thickness direction, a large space is required, which may cause the optoelectronic hybrid substrate 1 to become larger.

[0158] Therefore, in the above-described optoelectronic hybrid board 1, in order to manage the heat of the electrical transmission wiring 19 and to save space, a part of the flat wiring 25 and the core layer 22 are disposed opposite each other in the thickness direction. In other words, a part of the projection surface of the flat wiring 25 in the thickness direction overlaps with the projection surface of the core layer 22 in the thickness direction.

[0159] That is, in the above-described photoelectric hybrid substrate 1, the flat wiring 25 is less likely to accumulate heat than the non-flat wiring 26. Therefore, when the projection surface in the thickness direction of the flat wiring 25 overlaps with the projection surface in the thickness direction of the core layer 22, heat is less likely to be transmitted to the core layer 22 than when the projection surface in the thickness direction of the non-flat wiring 26 overlaps with the projection surface in the thickness direction of the core layer 22.

[0160] In particular, when only a portion of the projection surface in the thickness direction of the flat wiring 25 overlaps with the projection surface in the thickness direction of the core layer 22, heat is less likely to be transmitted to the core layer 22 than when the entire projection surface in the thickness direction of the flat wiring 25 overlaps with the projection surface in the thickness direction of the core layer 22.

[0161] Therefore, the optoelectronic hybrid board 1 can reduce space while suppressing the heat generated in the conductor layer 13 from being transferred to the core layer 22.

[0162] 6) Action and effect According to the above-described optoelectronic hybrid board 1, heat generated in the conductor layer 13 can be prevented from being transferred to the core layer 22, thereby enabling efficient heat management.

[0163] More specifically, in recent years, there has been a demand for smaller and / or thinner devices of various kinds. Therefore, in the field of the optoelectronic hybrid board 1, there has also been a demand for smaller and / or thinner electric circuit boards 3. Therefore, miniaturization and / or thinner wiring of the electric circuit boards 3 have been considered.

[0164] However, miniaturizing and / or thinning the wiring of the electric circuit board 3 causes an increase in resistance, resulting in electrical loss. Furthermore, electrical energy resulting from electrical loss may be converted into thermal energy and conducted to the optical waveguide layer. In such cases, optical transmission loss may occur in the optical waveguide layer. Therefore, in the field of optoelectronic hybrid boards 1, a new challenge is being faced: the management of heat generated in the wiring.

[0165] In contrast, in the above-mentioned optoelectronic hybrid substrate 1, the conductor layer 13 includes flat wiring 25 that satisfies the above formula (1). Such flat wiring 25 is less likely to accumulate heat than non-flat wiring 26 that does not satisfy the above formula (1). Furthermore, in the above-mentioned optoelectronic hybrid substrate 1, the distance between the conductor layer 13 and the core layer 22 satisfies the above formula (2), so that heat generated in the conductor layer 13 is less likely to be transmitted to the core layer 22.

[0166] Therefore, the optoelectronic hybrid board 1 can prevent the heat generated in the conductor layer 13 from being transmitted to the core layer 22. That is, the optoelectronic hybrid board 1 can manage the heat of the conductor layer 13.

[0167] Furthermore, in the above-described optoelectronic hybrid substrate 1, the flat wiring 25 is less likely to accumulate heat than the non-flat wiring 26. Therefore, as long as the optoelectronic hybrid substrate 1 includes at least one flat wiring 25, it can further include a non-flat wiring 26.

[0168] Furthermore, in the above-described photoelectric hybrid substrate 1, the non-flat wiring 26 is more likely to accumulate heat than the flat wiring 25. In such a case, unless at least a part of the projection surface in the thickness direction of the non-flat wiring 26 overlaps with the projection surface in the thickness direction of the core layer 22, heat is less likely to be transmitted to the core layer.

[0169] Therefore, according to the above-described photoelectric hybrid board 1, the heat generated in the conductor layer 13 can be prevented from being transmitted to the core layer 22.

[0170] Furthermore, in the above-described photoelectric hybrid substrate 1, the non-flat wiring 26 is more likely to accumulate heat than the flat wiring 25. In such a case, if the entire projection surface in the thickness direction of the non-flat wiring 26 does not overlap the projection surface in the thickness direction of the core layer 22, heat is even less likely to be transmitted to the core layer 22.

[0171] Therefore, according to the above-described photoelectric hybrid board 1, the transfer of heat generated in the conductor layer 13 to the core layer 22 can be further suppressed.

[0172] Furthermore, in the above-described photoelectric hybrid board 1, the flat wiring 25 is less likely to accumulate heat than the non-flat wiring 26. Therefore, when the projection surface in the thickness direction of the flat wiring 25 overlaps with the projection surface in the thickness direction of the core layer 22, heat is less likely to be transmitted to the core layer 22 than when the projection surface in the thickness direction of the non-flat wiring 26 overlaps with the projection surface in the thickness direction of the core layer 22.

[0173] Furthermore, when a portion of the projection surface in the thickness direction of the flat wiring 25 overlaps with the projection surface in the thickness direction of the core layer 22, heat is less likely to be transmitted to the core layer 22 than when the entire projection surface in the thickness direction of the flat wiring 25 overlaps with the projection surface in the thickness direction of the core layer 22.

[0174] Therefore, according to the above-described photoelectric hybrid board 1, the transfer of heat generated in the conductor layer 13 to the core layer 22 can be further suppressed.

[0175] Furthermore, in the above-described optoelectronic hybrid board 1, the metal supporting board 11 has relatively excellent heat dissipation properties. Therefore, if the optoelectronic hybrid board 1 includes the metal supporting board 11, heat can be dissipated efficiently.

[0176] Therefore, according to the above-described photoelectric hybrid board 1, the heat generated in the conductor layer 13 can be prevented from being transmitted to the core layer 22.

[0177] Furthermore, in the above-mentioned optoelectronic hybrid substrate 1, if the glass transition temperature of the undercladding layer 21 is equal to or higher than the predetermined temperature and the glass transition temperature of the core layer 22 is equal to or higher than the predetermined temperature, the optical waveguide film 2 has excellent heat resistance.

[0178] 7) Variation In the following modifications, the same components and steps as those in the above-described embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. Each modification can achieve the same effects as those in the above-described embodiment. Furthermore, the embodiment and its modifications can be combined as appropriate.

[0179] In the above-described photoelectric hybrid board 1, the flexible circuit board 3 includes a metal supporting board 11, but as shown in FIGS. 3A and 3B, the flexible circuit board 3 does not necessarily have to include a metal supporting board 11.

[0180] More specifically, as shown in Figures 3A and 3B, the wired circuit board may be a flexible circuit board 3 that includes a base insulating layer 12, a conductor layer 13, and a cover insulating layer 14, and does not include a metal supporting board 11.

[0181] From the viewpoint of heat management, the flexible circuit board 3 preferably includes a metal supporting board 11. More specifically, the metal supporting board 11 has heat dissipation properties. Therefore, if the flexible circuit board 3 includes the metal supporting board 11, it is possible to prevent heat generated in the conductor layer 13 from being transmitted to the core layer 22. Furthermore, if the flexible circuit board 3 includes the metal supporting board 11, the optoelectronic hybrid board 1 has excellent mechanical strength.

[0182] Although not shown in detail, the arrangement of the metal supporting board 11 in the above-described optoelectronic hybrid board 1 is not particularly limited. For example, the metal supporting board 11 may be arranged so as to be in contact with the surface on the other side in the thickness direction of the optical waveguide film 2 (i.e., the other side in the thickness direction of the overclad layer 23). The metal supporting board 11 may also be arranged so as to be in contact with the surface on one side in the thickness direction of the cover insulating layer 14.

[0183] Although not shown in detail, the shape of the metal supporting board 11 in the above-described optoelectronic hybrid board 1 may be, for example, such that the metal supporting board 11 is partially cut out at any position. For example, the metal supporting board 11 may be cut out in a slit shape so as not to overlap any conductor layer 13 in the thickness direction. When the metal supporting board 11 is cut out, excellent impedance characteristics are obtained.

[0184] Although not shown in detail, the number of metal supporting boards 11 in the above-described optoelectronic hybrid board 1 is not particularly limited. For example, the flexible circuit board 3 may include a plurality of metal supporting boards 11. In such a case, the arrangement and shape of each metal supporting board 11 are not particularly limited, and may be any of the arrangements and shapes described above.

[0185] Furthermore, in the above-mentioned photoelectric hybrid substrate 1, the base insulating layer 12 has an opening 16, but if the base insulating layer 12 has sufficient optical transparency, i.e., if an optical signal can pass through the base insulating layer 12, the base insulating layer 12 does not need to have the opening 16.

[0186] Although not shown in detail, the number of optical-electrical transmission wirings 18 and the number of electrical transmission wirings 19 are not particularly limited and can be changed to any number. The number of light-emitting elements 201 and the number of light-receiving elements 202 mounted on the optoelectronic hybrid board 1 are not particularly limited and can be changed to any number. For example, the above-described optoelectronic hybrid board 1 can mount two light-emitting elements 201 and two light-receiving elements 202, enabling bidirectional communication between the first external board 101 and the second external board 102. However, the optoelectronic hybrid board 1 may also be configured to mount, for example, one light-emitting element 201 and one light-receiving element 202, enabling unidirectional communication between the first external board 101 and the second external board 102.

[0187] Although not shown in detail, the number of core layers 22 is not particularly limited and can be changed to any number. For example, the number of core layers 22 may be one, or three or more. Although not shown in detail, the optical waveguide film 2 may include, as necessary, dummy core layers (not shown) and dummy mirrors (not shown) that do not transmit optical signals.

[0188] 4, the above-described optoelectronic hybrid board 1 can include a heat dissipation member 5 in addition to the metal supporting board 11. Preferably, the optoelectronic hybrid board 1 includes the heat dissipation member 5.

[0189] The heat dissipation member 5 is made of, for example, a known heat dissipation material. Examples of the heat dissipation material include resin members containing thermally conductive fillers. Examples of resins include known thermoplastic resins and thermosetting resins. Examples of the thermally conductive fillers include metal fillers and inorganic fillers. Examples of the metal fillers include metal oxides, specifically aluminum oxide, silver oxide, copper oxide, titanium oxide, and barium oxide. Examples of the inorganic fillers include silicon and carbon. Examples of the heat dissipation member 5 also include metal members (excluding the metal supporting board 11). The shape of the heat dissipation member 5 is not particularly limited, but may be, for example, a sheet shape. The shape of the heat dissipation member 5 is not particularly limited, but may be, for example, one.

[0190] The arrangement of the heat dissipation member 5 is not particularly limited. From the viewpoint of heat dissipation efficiency, the heat dissipation member 5 preferably contacts the flexible circuit board 3 and / or the optical waveguide film 2, as shown in Fig. 4. That is, the heat dissipation member 5 preferably contacts the cover insulating layer 14 of the flexible circuit board 3 (see the solid line in Fig. 4), or the overclad layer 23 of the optical waveguide film 2 (see the phantom line in Fig. 4), or both.

[0191] In the above-mentioned optoelectronic hybrid board 1, heat can be efficiently dissipated if the heat dissipation member 5 is in contact with the flexible circuit board 3 and / or the optical waveguide film 2. Therefore, according to the above-mentioned optoelectronic hybrid board 1, it is possible to more efficiently suppress the heat generated in the conductor layer 13 from being transmitted to the core layer 22.

[0192] Furthermore, in the above-described optoelectronic hybrid board 1, the conductor layer 13 is a single layer, but the conductor layer 13 may be multi-layered. That is, although not shown in detail, the flexible circuit board 3 may be a multi-layer wiring circuit board (not shown) that includes multi-layer wiring as the conductor layer 13. When the conductor layer 13 is multi-layered, for example, the electrical transmission wiring 19 may be multi-layered, the optical-electrical transmission wiring 18 may be multi-layered, or both of these may be multi-layered.

[0193] From the viewpoint of heat management, the conductor layer 13 is preferably a single layer (one layer). That is, if the conductor layer 13 is a multilayer, the conductor layer 13 is prone to heat accumulation. In contrast, if the conductor layer 13 is a single layer (one layer), heat accumulation in the conductor layer 13 can be suppressed. As a result, the heat generated in the conductor layer 13 can be suppressed from being transferred to the core layer 22.

[0194] Although not shown in detail, the optical waveguide film 2 may be disposed on only a part of the flexible circuit board 3. Preferably, the optical waveguide film 2 is disposed over the entire surface of the flexible circuit board 3.

[0195] Although not shown in detail, the number of optical-electrical transmission wirings 18 and the number of electrical transmission wirings 19 are not particularly limited and can be changed to any number. Although not shown in detail, the number of flat wirings 25 and non-flat wirings 26 are not particularly limited and can be changed to any number.

[0196] Although not shown in detail, the number of core layers 22 is not particularly limited and can be changed to any number. For example, the number of core layers 22 may be one, or three or more. Although not shown in detail, the optical waveguide film 2 may include, as necessary, dummy core layers (not shown) and dummy mirrors (not shown) that do not transmit optical signals.

[0197] Furthermore, although not shown in detail, the relative arrangement of the projection surface in the thickness direction of the flat wiring 25, the projection surface in the thickness direction of the non-flat wiring 26, and the projection surface in the thickness direction of the core layer 22 is not limited to the above.

[0198] In other words, in the above description, a portion of the projection surface in the thickness direction of the flat wiring 25 overlaps with the projection surface in the thickness direction of the core layer 22, and the projection surface in the thickness direction of the non-flat wiring 26 does not overlap with the projection surface in the thickness direction of the core layer 22.

[0199] In contrast to this, for example, a portion of the projection surface in the thickness direction of the flat wiring 25 may overlap with a portion of the projection surface in the thickness direction of the core layer 22, and a portion of the projection surface in the thickness direction of the non-flat wiring 26 may overlap with the projection surface in the thickness direction of the core layer 22.

[0200] Also, for example, a portion of the projection surface in the thickness direction of the flat wiring 25 may overlap with a portion of the projection surface in the thickness direction of the core layer 22, and the entire projection surface in the thickness direction of the non-flat wiring 26 may overlap with the projection surface in the thickness direction of the core layer 22.

[0201] Also, for example, the entire projection surface in the thickness direction of the flat wiring 25 may overlap with the projection surface in the thickness direction of the core layer 22, and the projection surface in the thickness direction of the non-flat wiring 26 may not overlap with the projection surface in the thickness direction of the core layer 22.

[0202] Also, for example, the entire projection surface in the thickness direction of the flat wiring 25 may overlap with a portion of the projection surface in the thickness direction of the core layer 22, and a portion of the projection surface in the thickness direction of the non-flat wiring 26 may overlap with the projection surface in the thickness direction of the core layer 22.

[0203] Also, for example, the entire projection surface in the thickness direction of the flat wiring 25 may overlap with a portion of the projection surface in the thickness direction of the core layer 22, and the entire projection surface in the thickness direction of the non-flat wiring 26 may overlap with the projection surface in the thickness direction of the core layer 22.

[0204] Furthermore, for example, the projection surface in the thickness direction of the flat wiring 25 and the projection surface in the thickness direction of the core layer 22 may not overlap, and the projection surface in the thickness direction of the non-flat wiring 26 and the projection surface in the thickness direction of the core layer 22 may not overlap.

[0205] Also, for example, the projection surface in the thickness direction of the flat wiring 25 and the projection surface in the thickness direction of the core layer 22 may not overlap, and a portion of the projection surface in the thickness direction of the non-flat wiring 26 may overlap with the projection surface in the thickness direction of the core layer 22.

[0206] Also, for example, the projection surface in the thickness direction of the flat wiring 25 and the projection surface in the thickness direction of the core layer 22 may not overlap, and the entire projection surface in the thickness direction of the non-flat wiring 26 may overlap with the projection surface in the thickness direction of the core layer 22.

[0207] 2. Optical Module The above-described optoelectronic hybrid board 1 is suitable for use in the field of optical modules.

[0208] 1, the optical module 10 includes the above-described optoelectronic hybrid board 1 and an optoelectronic conversion element 200 mounted on the optoelectronic hybrid board 1. More specifically, as shown in FIG. 1, the optical module 10 includes the above-described optoelectronic hybrid board 1, a plurality of (e.g., two) light-emitting elements 201 mounted on the optoelectronic hybrid board 1, and a plurality of (e.g., two) light-receiving elements 202 mounted on the optoelectronic hybrid board 1.

[0209] Although not shown, the optical module 10 may also include a known driving element as needed. The driving element is disposed, for example, upstream of the light-emitting element 201 in the optical-electrical transmission wiring 18a and the optical-electrical transmission wiring 18c. Although not shown, the optical module 10 may also include a known amplifying element as needed. The amplifying element is disposed, for example, downstream of the light-receiving element 202 in the optical-electrical transmission wiring 18b and the optical-electrical transmission wiring 18d.

[0210] Such an optical module 10 includes the above-described optoelectronic hybrid substrate 1. Therefore, such an optical module 10 can prevent heat generated in the conductor layer 13 from being transmitted to the core layer 22. In other words, the above-described optical module 10 can manage the heat of the conductor layer 13.

[0211] 3.Electronic equipment The above-described optoelectronic hybrid board 1 and optical module 10 are suitably used in the field of electronic devices. That is, as shown in FIG.

[0212] The electronic device 20 also includes a housing 30 that houses the optical module 10. The housing 30 is not particularly limited and is made of a known material. The housing 30 is preferably made of the above-mentioned heat dissipation material.

[0213] The arrangement of the housing 30 is not particularly limited. From the viewpoint of heat dissipation efficiency, the housing 30 preferably contacts the flexible circuit board 3 and / or the optical waveguide film 2, as shown in FIG. 5. That is, the housing 30 preferably contacts the cover insulating layer 14 of the flexible circuit board 3 (see the solid line in FIG. 5), or the overclad layer 23 of the optical waveguide film 2 (see the imaginary line in FIG. 5), or both. Furthermore, if the optoelectronic hybrid board 1 includes a heat dissipation member 5, the housing 30 can contact the heat dissipation member.

[0214] Such an electronic device 20 includes the above-described optoelectronic hybrid substrate 1. Therefore, such an electronic device 20 can prevent heat generated in the conductor layer 13 from being transferred to the core layer 22. That is, the above-described electronic device 20 can manage the heat of the conductor layer 13. [Explanation of symbols]

[0215] 1 Optoelectronic mixed board 2. Optical waveguide film 3 Flexible Circuit Board 5 Heat dissipation material 10 Optical Modules 11 Metal support substrate 12 Base insulation layer 13 Conductor layer 14 Cover insulation layer 15 through holes 15A Light-emitting side through hole 15B Receiving side through hole 16 Opening 16A Light-emitting side opening 16B Receiving side aperture 17 Wiring section 18 Optical transmission wiring 19 Electrical transmission wiring 19A straight wiring 19B Detour wiring 20 Electronic equipment 21 Underclad layer 22 Core layer 23 Overclad layer 24. Mirror 24A Light-emitting side mirror 24B Receiving mirror 25 Flat wiring 26 Non-flat wiring 27 Terminal section 30 Case 100 External board 101 First external board 102 Second external board 200 Photoelectric conversion element 201 Light-emitting element 201A First light-emitting element 201B second light-emitting element 202 Photodetector 202A First light receiving element 202B Second light receiving element

Claims

1. an optical waveguide layer extending along the longitudinal direction; a wiring circuit board extending along the longitudinal direction and disposed on one side of the optical waveguide layer in the thickness direction, the optical waveguide layer includes an underclad layer and a core layer in this order from one side to the other side in a thickness direction; the wired circuit board includes an insulating base layer and a conductor layer in this order from the other side to the one side in a thickness direction, the conductor layer has flat wiring extending along the longitudinal direction, The length W in the width direction of the flat wire １ and, The length H of the flat wire in the thickness direction １ and satisfy the following formula (1), The distance S between the surface of one side in the thickness direction of the core layer and the surface of one side in the thickness direction of the base insulating layer １ An optoelectronic hybrid board that satisfies the following formula (2). H １ / W １ ≦ 0.15 (1) S １ ≧ 3μm (2)

2. the conductor layer includes non-flat wiring extending along a longitudinal direction, The length W in the width direction of the non-flat wiring ２ and, The length H of the non-flat wiring in the thickness direction ２ The optoelectronic hybrid substrate according to claim 1 , wherein H ２ / W ２ > 0.15 (3)

3. In at least one of the non-flat wirings, At least a part of the projection surface in the thickness direction of the non-flat wiring is The optoelectronic hybrid board according to claim 2 , wherein the core layer does not overlap with a projection plane in a thickness direction thereof.

4. In at least one of the non-flat wirings, The entire projection surface in the thickness direction of the non-flat wiring is The optoelectronic hybrid board according to claim 3 , wherein the core layer does not overlap with a projection plane in a thickness direction thereof.

5. A part of the projection surface in the thickness direction of the flat wiring is The optoelectronic hybrid board according to claim 2 , which overlaps with a projection plane in a thickness direction of the core layer.

6. the printed circuit board includes a metal supporting substrate; The optoelectronic hybrid board according to claim 1 , wherein the metal supporting board is disposed on the other side in the thickness direction of the insulating base layer.

7. Further, a heat dissipation member is provided, The optoelectronic hybrid board according to claim 1 , wherein the heat dissipation member is in contact with the wiring circuit board and / or the optical waveguide layer.

8. The undercladding layer has a glass transition temperature of 50°C or higher, The optoelectronic hybrid board according to claim 1 , wherein the core layer has a glass transition temperature of 50° C. or higher.

9. The photoelectric hybrid substrate according to any one of claims 1 to 8, a photoelectric conversion element mounted on the photoelectric hybrid board; An optical module comprising:

10. An electronic device comprising the optical module according to claim 9.

11. Further, a housing for accommodating the optical module is provided, The electronic device according to claim 10 , wherein the housing is in contact with the printed circuit board and / or the optical waveguide layer of the optical module.

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