JP2012078527A - Optical waveguide module and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical waveguide module with reduced optical coupling loss between optical components and an optical waveguide and enabling high quality optical communication, and to provide an electronic equipment which includes the optical waveguide module and enables high quality optical communication.SOLUTION: An optical waveguide module includes an optical waveguide 1 in which a mirror 16 is formed, a circuit board 2 which is provided above the optical waveguide 1 and has a through-hole 24 whose cross-sectional area gradually expands downwards, and a light-emitting device 3 mounted on the circuit board 2. The optical waveguide 1 includes a support film 18, a clad layer 11, a core layer 13, a clad layer 12 and a cover film 19, which are laminated in this order from the bottom. On a top surface of the cover film 19, a ball lens 100 of a substantially spherical shape is disposed at an area on an optical path connecting between the mirror 16 and the light-emitting device 3. A part of the ball lens 100 is inserted into the through-hole 24.

Description

  The present invention relates to an optical waveguide module and an electronic device.

  In recent years, with the wave of computerization, wideband lines (broadband) capable of communicating a large amount of information at high speed have been spreading. Also, as devices for transmitting information to these broadband lines, transmission devices such as router devices and WDM (Wavelength Division Multiplexing) devices are used. In these transmission apparatuses, a large number of signal processing boards in which arithmetic elements such as LSIs and storage elements such as memories are combined are installed, and each line is interconnected.

  Each signal processing board has a circuit in which arithmetic elements, storage elements, etc. are connected by electrical wiring. However, with the increase in the amount of information to be processed in recent years, each board has a very high throughput. It is required to transmit. However, with the speeding up of information transmission, problems such as generation of crosstalk and high frequency noise and deterioration of electric signals are becoming apparent. For this reason, electrical wiring becomes a bottleneck, making it difficult to improve the throughput of the signal processing board. Similar problems are also becoming apparent in supercomputers and large-scale servers.

  On the other hand, an optical communication technique for transferring data using an optical carrier wave has been developed, and in recent years, an optical waveguide is becoming popular 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.

  If the electrical wiring in the signal processing board is replaced by such an optical waveguide, it is expected that the problem of the electrical wiring as described above will be solved and the signal processing board can be further increased in throughput.

  By the way, when replacing electric wiring with an optical waveguide, a light emitting element and a light receiving element are provided in order to perform mutual conversion between an electric signal and an optical signal, and an optical waveguide formed by optically connecting the light emitting element and the light receiving element therebetween. A waveguide module is used.

  For example, Patent Document 1 discloses an optical interface having a printed circuit board, a light emitting element mounted on the printed circuit board, and an optical waveguide provided on the lower surface side of the printed circuit board. The optical waveguide and the light emitting element are optically connected through a through hole, which is a through hole for transmitting an optical signal, formed on the printed board.

  However, the optical interface as described above has a problem that the optical coupling loss is large in the optical coupling between the light emitting element and the optical waveguide. Specifically, when the signal light emitted from the light emitting portion of the light emitting element passes through the through hole and enters the optical waveguide, the signal light radiates radially, so that all the signal light does not enter the optical waveguide. . For this reason, a part of the signal light does not contribute to the optical communication, resulting in an increase in optical coupling loss.

JP 2005-294407 A

  An object of the present invention is to provide an optical waveguide module capable of high-quality optical communication with a small optical coupling loss between the optical element and the optical waveguide, and an electronic device including the optical waveguide module and capable of high-quality optical communication. Is to provide.

Such an object is achieved by the present inventions (1) to (9) below.
(1) A core part, a clad part provided so as to cover the side surface of the core part, and provided in the middle or on an extension line of the core part, and converts the optical path of the core part to the outside of the clad part. An optical waveguide comprising: an optical path conversion unit;
An optical element provided outside the cladding,
A substrate provided between the optical waveguide and the optical element, and having a through-hole formed along an optical path connecting the optical path conversion unit and the optical element, and
The through hole is configured such that a cross-sectional area gradually expands or contracts along the optical path,
An optical waveguide module comprising a substantially spherical ball lens having at least a portion inserted into the through hole.

  (2) The optical waveguide module according to (1), wherein the ball lens has at least half of its diameter inserted into the through hole.

  (3) The optical waveguide module according to (1) or (2), wherein, of the two openings of the through hole, an opening having a smaller area cannot be passed through the ball lens.

  (4) The optical waveguide module according to any one of (1) to (3), wherein the through hole is configured such that a cross-sectional area continuously expands toward the optical waveguide.

  (5) The optical waveguide module according to (4), wherein the ball lens is fixed to the optical waveguide via an adhesive and is in contact with an inner surface of the through hole.

  (6) The optical waveguide module according to any one of (1) to (3), wherein the through hole is configured such that a cross-sectional area continuously decreases toward the optical waveguide side.

  (7) The optical waveguide according to any one of (1) to (6), wherein the focal point of the ball lens is positioned in at least one of the vicinity of the optical path conversion unit and the vicinity of the light emitting / receiving unit of the optical element. module.

  (8) The optical waveguide module according to any one of (1) to (7), wherein the ball lens is configured of any one of a resin material, a glass material, and a crystal material.

  (9) An electronic apparatus comprising the optical waveguide module according to any one of (1) to (8).

  According to the present invention, since the ball lens is provided, the optical coupling loss between the optical element and the optical waveguide can be reduced, so that the optical carrier wave having a high S / N ratio and capable of high-quality optical communication. A waveguide module is obtained.

  In addition, according to the present invention, by providing such an optical waveguide module, a highly reliable electronic device capable of high-quality optical communication can be obtained.

It is a perspective view which shows 1st Embodiment of the optical waveguide module of this invention. It is the sectional view on the AA line of FIG. FIG. 3 is a partially enlarged view of FIG. 2. It is a longitudinal cross-sectional view which shows the other structural example of the optical waveguide module shown in FIG. It is a longitudinal cross-sectional view which shows the other structural example of a through-hole. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the optical waveguide module of this invention. It is a figure (longitudinal sectional view) for demonstrating the method to manufacture the optical waveguide module shown in FIG.

  The optical waveguide module and the electronic device of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings.

<Optical waveguide module>
<< First Embodiment >>
First, a first embodiment of the optical waveguide module of the present invention will be described.

  1 is a perspective view showing a first embodiment of the optical waveguide module of the present invention, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. 3 is a partially enlarged view of FIG. In the following description, the upper side of FIGS. 2 and 3 is referred to as “upper” and the lower side is referred to as “lower”. In each figure, the thickness direction is emphasized.

  An optical waveguide module 10 shown in FIG. 1 includes an optical waveguide 1, a circuit board 2 (substrate) provided above the optical waveguide 1, and a light-emitting element 3 (optical element) mounted on the circuit board 2. Yes.

  The optical waveguide 1 has a long band shape, and the circuit board 2 and the light emitting element 3 are provided at one end of the optical waveguide 1 (the left end in FIG. 2).

  The light emitting element 3 is an element that converts an electrical signal into an optical signal, emits the optical signal from the light emitting unit 31, and enters the optical waveguide 1. The light emitting element 3 shown in FIG. 2 has a light emitting part 31 provided on the lower surface thereof, and an electrode 32 for energizing the light emitting part 31. The light emitting unit 31 emits an optical signal downward in FIG. Note that the arrows shown in FIG. 2 are examples of the optical path of the signal light emitted from the light emitting element 3.

  On the other hand, a mirror (optical path conversion unit) 16 is provided corresponding to the position of the light emitting element 3 in the optical waveguide 1. The mirror 16 converts the optical path of the optical waveguide 1 extending in the left-right direction in FIG. 2 to the outside of the optical waveguide 1. In FIG. 2, the mirror 16 is optically connected to the light emitting portion 31 of the light emitting element 3. The optical path is converted by 90 °. Through such a mirror 16, the signal light emitted from the light emitting element 3 can be incident on the core portion 14 of the optical waveguide 1. Although not shown, a light receiving element is provided at the other end of the optical waveguide 1. This light receiving element is also optically connected to the optical waveguide 1, and the signal light incident on the optical waveguide 1 reaches the light receiving element. As a result, optical communication is possible in the optical waveguide module 10.

  In the circuit board 2, a through-hole 24 that penetrates in the thickness direction is formed at a portion through which an optical path connecting the mirror 16 and the light emitting unit 31 passes. The through hole 24 is configured such that its cross-sectional area gradually expands or contracts along the optical path. Then, a substantially spherical ball lens 100 is placed in the through hole 24 so that a part thereof is inserted.

  The ball lens 100 suppresses the divergence of the signal light by converting the signal light incident on the optical waveguide 1 from the light emitting unit 31 into convergent light or parallel light, and increases the number of signals for the effective region of the mirror 16. Let the light reach. Therefore, by providing such a ball lens 100, the optical coupling efficiency between the light emitting element 3 and the optical waveguide 1 is improved.

Hereinafter, each part of the optical waveguide module 10 will be described in detail.
(Optical waveguide)
The optical waveguide 1 shown in FIG. 1 has a strip-shaped laminate in which a clad layer (first clad layer) 11, a core layer 13, and a clad layer (second clad layer) 12 are laminated in this order from below. ing. Among these, as shown in FIG. 1, the core layer 13 is formed with a single core portion 14 that is linear in a plan view, and a side cladding portion 15 that is adjacent to the side surface of the core portion 14. The core part 14 is extended | stretched along the longitudinal direction of a strip | belt-shaped laminated body, and is located in the approximate center of the width | variety of a laminated body. In FIG. 1, the core portion 14 is provided with dots.

  In the optical waveguide 1 shown in FIG. 2, the light incident through the mirror 16 is totally reflected at the interface between the core portion 14 and the clad portion (each clad layer 11, 12 and each side clad portion 15). It can be propagated to the end. Thereby, optical communication can be performed based on at least one of the blinking pattern of light received at the emitting end and the intensity pattern of light.

  In order to cause total reflection at the interface between the core part 14 and the clad part, a difference in refractive index needs to exist at the interface. Although the refractive index of the core part 14 should just be larger than the refractive index of a clad part, and the difference is not specifically limited, It is preferable that it is 0.5% or more of the refractive index of a clad part, and it is 0.8% or more. Is more preferable. On the other hand, the upper limit value may not be set, but is preferably about 5.5%. If the difference in refractive index is less than the lower limit, the effect of transmitting light may be reduced, and even if the upper limit is exceeded, no further increase in light transmission efficiency can be expected.

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

  Moreover, in the structure shown in FIG. 1, although the core part 14 is formed in linear form by planar view, you may be curving, branching, etc. in the middle, The shape is arbitrary.

  The cross-sectional shape of the core portion 14 is generally a square such as a square or a rectangle (rectangle), but is not particularly limited, and is not limited to a circle, such as a perfect circle or an ellipse, a rhombus, a triangle, or a pentagon. A polygon such as

  The width and height of the core portion 14 are not particularly limited, but are preferably about 1 to 200 μm, more preferably about 5 to 100 μm, and still more preferably about 20 to 70 μm.

  The constituent material of the core layer 13 is not particularly limited as long as the above-described refractive index difference is generated. Specifically, the core layer 13 is an acrylic resin, a methacrylic resin, a polycarbonate, a polystyrene, an epoxy resin, or an oxetane resin. Other cyclic ether resins, polyamides, polyimides, polybenzoxazoles, polysilanes, polysilazanes, and various resin materials such as cyclic olefin resins such as benzocyclobutene resins and norbornene resins, quartz glass, borosilicate glass Such as a glass material.

  Of these, norbornene resins are particularly preferable. These norbornene-based polymers include, for example, ring-opening metathesis polymerization (ROMP), combination of ROMP and hydrogenation reaction, polymerization by radical or cation, polymerization using a cationic palladium polymerization initiator, and other polymerization initiators ( For example, it can be obtained by any known polymerization method such as polymerization using a polymerization initiator of nickel or another transition metal).

  On the other hand, the clad layers 11 and 12 are located below and above the core layer 13, respectively. The clad layers 11 and 12 together with the side clad parts 15 constitute a clad part surrounding the outer periphery of the core part 14, thereby allowing the optical waveguide 1 to propagate the signal light without leaking. Functions as an optical path.

  The average thickness of the clad layers 11 and 12 is preferably about 0.1 to 1.5 times the average thickness of the core layer 13 (average height of each core portion 14). More preferably, the average thickness of the clad layers 11 and 12 is not particularly limited, but is usually preferably about 1 to 200 μm, and preferably about 5 to 100 μm. More preferably, it is about 10 to 60 μm. Thereby, the function as a clad layer is suitably exhibited while preventing the optical waveguide 1 from becoming unnecessarily large (thickened).

  Further, as the constituent material of each 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, but a norbornene polymer is particularly preferable.

  Further, when selecting the constituent material of the core layer 13 and the constituent materials of the clad layers 11 and 12, the material may be selected in consideration of the refractive index difference between them. Specifically, the refractive index of the constituent material of the core layer 13 is sufficiently larger than the refractive index of the cladding layers 11 and 12 in order to surely totally reflect light at the boundary between the core layer 13 and the cladding layers 11 and 12. What is necessary is just to select a material so that it may become. Thereby, a sufficient refractive index difference is obtained in the thickness direction of the optical waveguide 1, and light can be prevented from leaking from the core portion 14 to the cladding layers 11 and 12.

  From the viewpoint of suppressing light attenuation, it is also important that the adhesiveness (affinity) between the constituent material of the core layer 13 and the constituent materials of the cladding layers 11 and 12 is high.

  The optical waveguide 1 shown in FIG. 2 further includes a support film 18 provided on the lower surface of the clad layer 11 and a cover film 19 provided on the upper surface of the clad layer 12. These support film 18 and cover film 19 may be provided as necessary and may be omitted.

  Examples of the constituent material of the support film 18 and the cover film 19 include various resin materials such as polyethylene terephthalate (PET), polyolefin such as polyethylene and polypropylene, polyimide, and polyamide.

  Moreover, although each average thickness of the support film 18 and the cover film 19 is not specifically limited, It is preferable that it is about 5-200 micrometers, and it is more preferable that it is about 10-100 micrometers. Thereby, since the support film 18 and the cover film 19 have moderate rigidity, it becomes difficult to inhibit the flexibility of the optical waveguide 1. Moreover, the cover film 19 becomes difficult to inhibit light transmission.

  Note that the support film 18 and the clad layer 11 and the cover film 19 and the clad layer 12 are bonded or bonded, and as a method therefor, thermocompression bonding, bonding with an adhesive or a pressure-sensitive adhesive is used. Etc.

  Among these, as an adhesive layer, various hot-melt-adhesives (polyester type | system | group, modified olefin type | system | group) etc. are mentioned other than an acrylic adhesive, a urethane type adhesive agent, a silicone type adhesive agent, for example. Moreover, as a thing with especially high heat resistance, thermoplastic polyimide adhesive agents, such as a polyimide, a polyimide amide, a polyimide amide ether, a polyester imide, a polyimide ether, are used preferably. Since the adhesive layer made of such a material is relatively flexible, even if the shape of the optical waveguide 1 changes, the change can be freely followed. As a result, it is possible to reliably prevent peeling due to shape change.

  The average thickness of such an adhesive layer is not particularly limited, but is preferably about 1 to 100 μm, and more preferably about 5 to 60 μm.

  As described above, the mirror 16 is provided in the middle of the optical waveguide 1 (see FIG. 2). The mirror 16 is formed of an inner wall surface of a space (cavity) obtained by digging in the middle of the optical waveguide 1. A part of this inner wall surface is a plane that crosses the core portion 14 at an angle of 45 °, and this plane becomes the mirror 16. The optical waveguide 1 and the light emitting unit 31 are optically connected via the mirror 16.

  A reflective film may be formed on the mirror 16 as necessary. As the reflective film, a metal film such as Au, Ag, or Al is preferably used.

  Further, the mirror 16 can be replaced by an optical path conversion means such as a bent waveguide that bends the optical axis of the core portion 14 by 90 °.

  A ball lens 100 is placed on the upper surface of the cladding layer 12. The ball lens 100 will be described in detail later.

(Light emitting element)
As described above, the light-emitting element 3 has the light-emitting portion 31 and the electrode 32 on the lower surface, and specifically, a semiconductor laser such as a surface-emitting laser (VCSEL), a light-emitting diode (LED), or the like. It is a light emitting element.

  On the other hand, the semiconductor element 4 is mounted on the circuit board 2 of the optical waveguide module 10 shown in FIGS. The semiconductor element 4 is an element that controls the operation of the light emitting element 3, and has an electrode 42 on the lower surface. Examples of the semiconductor element 4 include a combination IC including a driver IC, a transimpedance amplifier (TIA), a limiting amplifier (LA), and various LSIs and RAMs.

  The light emitting element 3 and the semiconductor element 4 are electrically connected by a circuit board 2 to be described later, and the semiconductor element 4 is configured so that the light emission pattern of the light emitting element 3 and the intensity pattern of light emission can be controlled.

(Circuit board)
A circuit board 2 is provided above the optical waveguide 1, and the lower surface of the circuit board 2 and the upper surface of the optical waveguide 1 are bonded via an adhesive layer 5.

  As shown in FIG. 2, the circuit board 2 includes an insulating substrate 21, a conductor layer 22 provided on the lower surface thereof, and a conductor layer 23 provided on the upper surface. The light emitting element 3 and the semiconductor element 4 mounted on the circuit board 2 are electrically connected via the conductor layer 23.

  Here, the insulating substrate 21 is formed with a through hole 24 formed along an optical path connecting the light emitting portion 31 of the light emitting element 3 and the mirror 16 of the optical waveguide 1. The through hole 24 is configured to penetrate the insulating substrate 21 in the thickness direction along the optical path.

  Further, in the insulating substrate 21 shown in FIG. 3, the through holes 24 have circular shapes in both openings, and the cross-sectional area gradually (continuously) expands downward. It has a tapered shape. In other words, the through hole 24 has a truncated cone shape.

  In addition, the shape of both opening parts of the through-hole 24 is not specifically limited, In addition to circles, such as a perfect circle, an ellipse, and an ellipse, polygons, such as a triangle, a rectangle, a hexagon, etc. may be sufficient.

Further, the shape of the through hole 24 may be a taper shape whose cross-sectional area continuously changes, but may be a shape whose cross-sectional area changes stepwise (discontinuously). That is, the shape in which the cross-sectional area gradually expands refers to both a shape in which the expansion method is continuous and a shape in which it is discontinuous.
In such a through hole 24, a substantially spherical ball lens described later is inserted.

  The insulating substrate 21 is preferably flexible. The flexible insulating substrate 21 contributes to improving the adhesion between the circuit board 2 and the optical waveguide 1 and has an excellent followability to a shape change. As a result, when the optical waveguide 1 is flexible, the entire optical waveguide module 10 is also flexible and has excellent mountability. Further, when the optical waveguide module 10 is bent, it is possible to reliably prevent the insulating substrate 21 and the conductor layers 22 and 23 from peeling and the circuit board 2 and the optical waveguide 1 from peeling. This prevents a decrease in insulation and a decrease in transmission efficiency.

  The Young's modulus (tensile modulus) of the insulating substrate 21 is preferably about 1 to 20 GPa and more preferably about 2 to 12 GPa in a general room temperature environment (around 20 to 25 ° C.). If the range of the Young's modulus is this level, the insulating substrate 21 has sufficient flexibility to obtain the above-described effects.

  Examples of the material constituting the insulating substrate 21 include various resin materials such as polyimide resins, polyamide resins, epoxy resins, various vinyl resins, and polyester resins such as polyethylene terephthalate resins. Of these, those mainly composed of a polyimide resin are preferably used. The polyimide resin is particularly suitable as a constituent material of the insulating substrate 21 because it has high heat resistance and excellent translucency and flexibility.

  Specific examples of the insulating substrate 21 include film substrates used for polyester copper-clad film substrates, polyimide copper-clad film substrates, aramid copper-clad film substrates, and the like.

  In addition, the average thickness of the insulating substrate 21 is preferably about 5 to 50 μm, and more preferably about 10 to 40 μm. The insulating substrate 21 having such a thickness has sufficient flexibility regardless of the constituent material. If the thickness of the insulating substrate 21 is within the above range, the optical waveguide module 10 can be thinned.

  Furthermore, if the thickness of the insulating substrate 21 is within the above range, it is possible to prevent the transmission efficiency from being lowered due to the divergence of the signal light. For example, the signal light emitted from the light emitting unit 31 of the light emitting element 3 is incident on the mirror 16 through the circuit board 2 while diverging at a constant emission angle, but the separation distance between the light emitting unit 31 and the mirror 16 is large. If it is too large, the signal light will diverge too much and the amount of light reaching the mirror 16 may be reduced. On the other hand, by setting the average thickness of the insulating substrate 21 within the above range, the separation distance between the light emitting unit 31 and the mirror 16 can be surely reduced, so that the signal light is diffused widely. The mirror 16 is reached. As a result, a decrease in the amount of light reaching the mirror 16 can be prevented, and a loss (optical coupling loss) associated with optical coupling between the light emitting element 3 and the optical waveguide 1 can be sufficiently reduced.

  The insulating substrate 21 may be a single substrate, or may be a multilayer substrate (build-up substrate) formed by stacking a plurality of substrates. In this case, a patterned conductor layer is included between the layers of the multilayer substrate, and an arbitrary electric circuit may be formed in the conductor layer. Thereby, a high-density electric circuit can be constructed in the insulating substrate 21.

  Further, the insulating substrate 21 may be provided with one or a plurality of through holes penetrating in the thickness direction, and these through holes are filled with a conductive material, or the through holes A conductive material film may be formed along the inner wall surface. This conductive material becomes a through via that electrically connects both surfaces of the insulating substrate 21.

  The conductor layer 22 and the conductor layer 23 provided on the insulating substrate 21 are each made of a conductive material. A predetermined pattern is formed on each of the conductor layers 22 and 23, and this pattern functions as a wiring. When the through via is formed in the insulating substrate 21, the through via and each of the conductor layers 22 and 23 are connected, whereby the conductor layer 22 and the conductor layer 23 are partially connected.

  Examples of the conductive material used for each of the conductor layers 22 and 23 include aluminum (Al), copper (Cu), gold (Au), silver (Ag), platinum (Pt), nickel (Ni), and tungsten (W ) And various metal materials such as molybdenum (Mo).

  Moreover, although the average thickness of each conductor layer 22 and 23 is suitably set according to the electrical conductivity etc. which are requested | required of wiring, it shall be about 1-30 micrometers, for example.

  Also, the width of the wiring pattern formed on each conductor layer 22 and 23 is appropriately set according to the electrical conductivity required for the wiring, the thickness of each conductor layer 22 and 23, etc., for example, about 2 to 1000 μm It is preferable that the thickness is about 5 to 500 μm.

  In addition, such a wiring pattern is patterned in advance on a separately prepared substrate, for example, a method of patterning a conductor layer once formed on the entire surface (for example, partially etching a copper foil of a copper-clad substrate). It is formed by a method of transferring a conductor layer.

  Also, each of the conductor layers 22 and 23 shown in FIG. 3 has openings 221 and 231 provided so as not to interfere with the optical path between the light emitting portion 31 of the light emitting element 3 and the mirror 16. As a result, a gap 222 having a height corresponding to the thickness of the conductor layer 22 is generated in the opening 221, and a gap 232 having a height corresponding to the thickness of the conductor layer 23 is generated in the opening 231.

  Further, the light emitting element 3 or the semiconductor element 4 and the conductor layer 23 are electrically and mechanically connected by various solders, various brazing materials and the like.

  Examples of the solder and brazing material include Sn—Pb lead solder, Sn—Ag—Cu, Sn—Zn—Bi, Sn—Cu, Sn—Ag—In—Bi, Sn—Zn. -Various Al-based lead-free solders, various low-temperature brazing materials defined by JIS, etc.

  In addition, as the light emitting element 3 and the semiconductor element 4, a package specification element such as a BGA (Ball Grid Array) type or an LGA (Land Grid Array) type is used, for example.

  Further, when the conductor layer 23 and the solder (or brazing material) are in contact with each other, there is a possibility that a part of the metal component constituting the conductor layer 23 is dissolved on the solder side. This phenomenon is called “copper erosion” because it often occurs particularly with respect to the copper conductor layer 23. If copper erosion occurs, the conductor layer 23 may be thinned or damaged, and the function of the conductor layer 23 may be impaired.

  Therefore, it is preferable to previously form a copper erosion prevention film (underlayer) as a solder underlayer on the surface of the conductor layer 23 in contact with the solder. By forming the copper erosion preventing film, copper erosion is prevented and the function of the conductor layer 23 can be maintained over a long period of time.

  Examples of the constituent material of the copper corrosion prevention film include nickel (Ni), gold (Au), platinum (Pt), tin (Sn), palladium (Pd), and the like. A single layer composed of one kind of metal composition may be used, or a composite layer containing two or more kinds (for example, a Ni—Au composite layer, a Ni—Sn composite layer, etc.) may be used.

  The average thickness of the copper erosion preventing film is not particularly limited, but is preferably about 0.05 to 5 μm, and more preferably about 0.1 to 3 μm. Thereby, it is possible to exhibit a sufficient copper erosion preventing action while suppressing the electrical resistance of the copper erosion preventing film itself.

  In addition, the electrical connection between the light emitting element 3 or the semiconductor element 4 and the conductor layer 23 is performed by wire bonding, anisotropic conductive film (ACF), anisotropic conductive paste (ACP), etc. in addition to the connection method described above. It may be carried out by a manufacturing method using

  Among them, according to wire bonding, even if a difference in thermal expansion occurs between the light emitting element 3 or the semiconductor element 4 and the circuit board 2, the difference in thermal expansion can be absorbed by a highly flexible bonding wire. , Stress concentration on the connecting portion is prevented.

  The circuit board 2 and the optical waveguide 1 are bonded to each other with an adhesive layer 5. Examples of the adhesive constituting the adhesive layer 5 include an epoxy adhesive, an acrylic adhesive, and a urethane adhesive. In addition to silicone adhesives, various hot melt adhesives (polyester-based, modified olefin-based) and the like can be mentioned. Moreover, as a thing with especially high heat resistance, thermoplastic polyimide adhesive agents, such as a polyimide, a polyimide amide, a polyimide amide ether, a polyester imide, a polyimide ether, are mentioned.

  In the optical waveguide module 10 as described above, the signal light emitted from the light emitting portion 31 of the light emitting element 3 passes through the gap 232, the ball lens 100 partially inserted into the through hole 24, the gap 222, and the adhesive layer 5. Then, the light enters the optical waveguide 1.

  Note that the optical waveguide module 10 may have the circuit board 2 at the other end of the optical waveguide 1 or may have a connector or the like responsible for connection with other optical components.

FIG. 4 is a longitudinal sectional view showing another configuration example of the optical waveguide module shown in FIG.
In the optical waveguide module 10 shown in FIG. 4A, the circuit board 2 is also provided on the upper surface of the other end of the optical waveguide 1 (the right end in FIGS. 2 and 4). A light receiving element 7 and a semiconductor element 4 are mounted on the circuit board 2. A mirror 16 is formed in the optical waveguide 1 corresponding to the position of the light receiving portion 71 of the light receiving element 7.

  In such an optical waveguide module 10, when the signal light emitted from the optical waveguide 1 through the mirror 16 reaches the light receiving portion 71 of the light receiving element 7, the optical signal is converted into an electrical signal. In this way, optical communication between both ends of the optical waveguide 1 is performed.

  On the other hand, in the optical waveguide module 10 shown in FIG. 4B, a connector 20 that is connected to other optical components is provided at the other end of the optical waveguide 1. Examples of the connector 20 include a PMT connector used for connection with an optical fiber. By connecting the optical waveguide module 10 to the optical fiber via the connector 20, optical communication over a longer distance becomes possible.

  In FIG. 4, the case where one-to-one optical communication is performed between one end and the other end of the optical waveguide 1 has been described. However, a plurality of optical paths are provided at the other end of the optical waveguide 1. An optical splitter that can be branched may be connected.

(Ball lens)
Here, on the surface of the optical waveguide 1 (the upper surface of the cladding layer 12), the ball lens 100 is placed in the through-hole 24 at the portion where the optical path connecting the mirror 16 and the light emitting portion 31 passes. It is placed in a state in which a part thereof is inserted.

  Without such a ball lens 100, signal light diverges until signal light emitted from the light emitting section 31 enters the optical waveguide 1, and signal light that protrudes from the effective area of the mirror 16 is generated. . At this time, the protruding signal light is lost, and the amount of the signal light reflected by the mirror 16 is reduced, so that the S / N ratio of the optical signal is lowered.

  On the other hand, by providing the ball lens 100, a signal light convergence (convergence) function is imparted to the surface of the optical waveguide 1. As a result, by causing more signal light to enter the mirror 16, occurrence of loss of signal light is suppressed, and the S / N ratio of optical communication can be increased. And the optical waveguide module 10 which can provide a reliable and high quality optical communication is obtained.

  The ball lens 100 is a substantially spherical lens made of a transparent material. The shape of the ball lens 100 may be a sphere similar to a true sphere, an elliptic sphere, or the like in addition to a true sphere.

  Further, the surface of the ball lens 100 may be subjected to an antireflection treatment for preventing the reflection of the signal light incident on the ball lens 100 as necessary. Examples of the antireflection treatment include a treatment for forming minute irregularities on the surface of the ball lens 100, a treatment for forming an antireflection film on the surface of the ball lens 100, and the like.

  Among these, when forming minute unevenness on the surface of the ball lens 100, it is preferable that the pitch or depth (height) of the unevenness is equal to or less than the wavelength of the signal light incident on the ball lens 100. If the pitch and depth (height) of the irregularities are made equal to or less than the wavelength of the signal light, the refractive index of this region can be regarded as an intermediate value between the refractive index of air and the refractive index of the ball lens 100. As a result, the reflection of the signal light incident on the ball lens 100 is suppressed, and the incident efficiency of the signal light is improved.

  In addition, since the wavelength of the signal light radiate | emitted from the light emitting element 3 is generally about 150-1600 nm, the upper limit of the pitch and depth (height) of an unevenness | corrugation is set according to it.

  On the other hand, the lower limit of the pitch and depth (height) of the unevenness is not particularly limited, but is about 20 nm from the viewpoint of the ease of forming the unevenness and long-term reliability.

  The antireflection film is formed of a thin film having an optical film thickness that is an odd multiple of λ / 4, where λ is the wavelength of the signal light incident on the ball lens 100, for example. The antireflection film is not limited to one layer, and may be a multi-coating having two or more layers.

  Examples of transparent materials include acrylic resins, methacrylic resins, polycarbonates, polystyrenes, cyclic ether resins such as epoxy resins and oxetane resins, polyamides, polyimides, polybenzoxazoles, polysilanes, polysilazanes, and benzocyclobutenes. In addition to various resin materials such as cyclic olefin resins such as a series resin and a norbornene resin, various glass materials such as quartz glass and borosilicate glass, and various crystal materials such as sapphire and quartz are included.

  By the way, the ball lens 100 has more than half of its diameter inserted into the through hole 24 from below the through hole 24. Thereby, the ball lens 100 is securely fixed in the through hole 24, and the reliability of the optical waveguide module 10 is improved.

  Specifically, 50 to 95% of the diameter of the ball lens 100 is preferably inserted, and more preferably 60 to 90% is inserted. As a result, the ball lens 100 is securely fixed in the through hole 24, and the mechanical and optical connection between the ball lens 100 and the optical waveguide 1 is ensured by partly protruding. As a result, the optical coupling efficiency between the light emitting element 3 and the optical waveguide 1 is improved.

  Further, the through hole 24 shown in FIG. 3 has a tapered shape as described above. For this reason, when the ball lens 100 is inserted from below the through hole 24, the ball lens 100 and the inner surface of the through hole 24 come into contact with each other at a position where the diameter of the ball lens 100 and the inner diameter of the through hole 24 coincide with each other. In this case, the ball lens 100 is fixed. Therefore, the fixing position of the ball lens 100 can be strictly controlled by appropriately setting the shape of the through hole 24 based on the contact position with the ball lens 100.

  When the through hole 24 has a tapered shape such as a truncated cone shape or a truncated pyramid shape, the fixing position of the ball lens 100 is uniquely determined in both the thickness direction and the surface direction of the insulating substrate 21. Can do. Therefore, the reproducibility of the fixed position of the ball lens 100 can be reliably improved as long as the shape and the formation position of the through hole 24 are set accurately.

  In this case, the inner surface of the through-hole 24 inevitably gives a pressing force toward the center direction of the ball lens 100. For this reason, the ball lens 100 is not easily deformed and can be reliably fixed without being displaced.

  In addition, when the through hole 24 has a circular shape in plan view, a contact portion between the ball lens 100 and the inner surface of the through hole 24 is an annular region. As a result, the inner surface of the through-hole 24 comes into contact with the ball lens 100 without deviation, so that the ball lens 100 is more reliably fixed.

  In the case of the through hole 24 shown in FIG. 3, the annular region and the inner surface of the through hole 24 are in contact with each other above the ball lens 100, and the adhesive layer 5 is in contact below the ball lens 100. Therefore, the ball lens 100 is fixed by being supported at these two points. With such a fixing method, the ball lens 100 can be reliably fixed by sandwiching the ball lens 100 from above and below. Furthermore, since the ball lens 100 and the optical waveguide 1 are mechanically and optically connected by the adhesive layer 5, the incident efficiency of the signal light converged by the ball lens 100 on the optical waveguide 1 is particularly improved.

  The number of support points for the ball lens 100 is not particularly limited, and may be three or more.

  Moreover, even if the whole through-hole 24 does not have a taper shape, a part may just be a taper shape.

  The angle formed by the inner surface of the tapered through hole 24 with respect to the optical path connecting the light emitting portion 31 of the light emitting element 3 and the mirror 16 of the optical waveguide 1 is preferably about 5 to 85 °. More preferably, it is about ˜80 °. Thereby, the ball lens 100 can be more reliably fixed in both the thickness direction and the surface direction of the insulating substrate 21.

  Here, in the through hole 24, the upper opening 242 has a smaller area than the lower opening 241 and is configured not to allow the ball lens 100 to pass therethrough. As a result, in the through hole 24, the inserted ball lens 100 is surely in contact with the inner surface in the middle of the through hole 24, so that the position of the ball lens 100 can be uniquely determined, and the ball lens 100 can be securely connected. Can be fixed to. Further, the thickness of the optical waveguide module 10 is reduced by the amount inserted. Therefore, it is possible to reduce the thickness of the optical waveguide module 10 while fixing the ball lens 100.

  In the case of the through hole 24 shown in FIG. 3, since the through hole 24 has a truncated cone shape, each of the opening 241 and the opening 242 has a circular shape. Therefore, the inner diameter of the lower opening 241 is L1, the inner diameter of the upper opening 242 is L2, the diameter (maximum diameter) of the ball lens 100 is D, and the central axis of the through-hole 24 (the light emitting portion 31 of the light emitting element 3). When the angle formed by the inner surface of the through-hole 24 with respect to the optical path) to the mirror 16 is θ, both the relationship of L2 <Dcosθ and the relationship of D / cosθ <L1 are established in the through-hole 24. . When the through hole 24 satisfies such a relational expression, the ball lens 100 is in a state in which more than half of the diameter D is inserted into the through hole 24 and is in contact with the inner surface of the through hole 24. Can do. As a result, reliable fixation of the ball lens 100 and thinning of the optical waveguide module 10 can be achieved at a high level.

  Further, the diameter D of the ball lens 100 is appropriately set according to the size of the effective area of the mirror 16 and the numerical aperture (NA) of the light emitting element 3, but is preferably about 10 μm to 1 mm. Preferably, it is about 30 μm to 500 μm.

  Further, the diameter D of the ball lens 100 is preferably about 1.5 to 6 times the diameter of the light emitting part 31 of the light emitting element 3 (the diameter of the light receiving part 71 of the light receiving element 7), and is about 2 to 5 times. More preferably.

  The ball lens 100 is preferably configured so that its focal point is located in the vicinity of the mirror 16. The ball lens 100 having such a configuration can convert the signal light emitted radially from the light emitting unit 31 of the light emitting element 3 into parallel light or convergent light, and change the optical path so as not to diverge any more. As a result, it is possible to reliably suppress a loss associated with signal light divergence.

  The ball lens 100 is preferably configured so that its focal point is located in the vicinity of the light emitting portion 31 of the light emitting element 3. The ball lens 100 having such a configuration can reduce the signal light protruding from the mirror 16 and reliably suppress the optical coupling loss of the signal light.

  As described above, by inserting a part of the ball lens 100 into the through hole 24, the thickness of the optical waveguide module 10 is avoided from being significantly increased (while the height of the relatively bulky ball lens 100 is offset). ), The position of the ball lens 100 can be uniquely determined, and can be securely fixed at that position. Thereby, the positional relationship between the ball lens 100, the light emitting element 3, and the mirror 16 can be reproduced as designed, and the optical coupling efficiency can be reliably increased. In other words, numerical aperture matching can be achieved between the light emitting element 3 and the mirror 16. As a result, the optical waveguide module 10 that can increase the S / N ratio of optical communication and can provide high-quality optical communication with high reliability is obtained.

  The ball lens 100 has the shortest focal length among lenses using other spherical surfaces. For this reason, even if the distance between the ball lens 100 and the light emitting element 3 and the mirror 16 is shortened by inserting the ball lens 100 into the through hole 24, the focus of the ball lens 100 can be easily adjusted to the target position. Thus, the signal light can be reliably converged.

  In addition, the ball lens 100 is easy to manufacture and inexpensive, and because of its high fluidity based on its shape, the mounting operation is relatively easy. For this reason, a decrease in yield due to manufacturing variations is suppressed, and the optical waveguide module 10 with little individual difference can be manufactured.

  If necessary, at least a gap between the light emitting element 3 and the circuit board 2, a gap 232, a region above the ball lens 100 in the through hole 24, a region below the ball lens 100 in the through hole 24, and at least the gap 222. One may be filled with a sealing material. In addition, the gap between the semiconductor element 4 and the circuit board 2 may be filled with a sealing material.

  These fillers enhance the weather resistance (heat resistance, moisture resistance, atmospheric pressure change, etc.) of the light emitting element 3 and the semiconductor element 4 and reliably protect the light emitting element 3 and the semiconductor element 4 from vibration, external force, foreign matter adhesion, and the like. can do.

  Examples of the sealing material include epoxy resins, polyester resins, polyurethane resins, silicone resins, and the like.

  Further, the ball lens 100 as described above may be provided on the light receiving element side. FIG. 4A shows a case where the ball lens 100 is provided on the light receiving element 7 side. The ball lens 100 provided on the light receiving element 7 side in FIG. 4A is placed in a state where a part thereof is inserted into the through hole 24 formed in the circuit board 2.

In such an optical waveguide module 10, when the signal light propagating through the optical waveguide 1 and reflected by the mirror 16 enters the light receiving portion 71 of the light receiving element 7, the signal light diverges and protrudes from the light receiving portion 71. Signal light can be reduced. As a result, the optical coupling loss on the light receiving element side of the optical waveguide module 10 can be reliably suppressed.
Further, the through hole 24 may have a vertical cross-sectional shape as shown in FIG.

FIG. 5 is a longitudinal sectional view showing another configuration example of the through hole.
Among these, the through holes 24 shown in FIGS. 5A and 5B are only partially tapered, and the through holes 24 shown in FIGS. 5C and 5D are inclined on the inner surface. The through holes 24 shown in FIGS. 5 (e) and 5 (f) are partially curved at the inner surface.

<< Second Embodiment >>
Next, a second embodiment of the optical waveguide module of the present invention will be described.
FIG. 6 is a longitudinal sectional view showing a second embodiment of the optical waveguide module of the present invention.

  Hereinafter, although the second embodiment will be described, the description will focus on differences from the first embodiment, and the description of the same matters will be omitted. In FIG. 6, 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 optical waveguide module 10 shown in FIG. 6 is such that the shape of the through hole 24 is upside down from that shown in FIG. 3, and a part of the through hole 24 is inserted into the through hole 24 from the opening above the through hole 24. Except that the ball lens 100 is placed, the present embodiment is the same as the first embodiment.

  That is, in the optical waveguide module 10 shown in FIG. 6, the shape of the through hole 24 is configured such that the cross-sectional area continuously decreases toward the optical waveguide 1 side. As in the case of FIG. 3, by inserting a part of the ball lens 100 into the through hole 24, the position of the ball lens 100 is unambiguous while avoiding a significant increase in the thickness of the optical waveguide module 10. And can be fixed securely at that position.

  In the case of FIG. 6, the upper part of the ball lens 100 protrudes so that the optical connection between the light emitting element 3 and the ball lens 100 is ensured. In particular, by disposing the ball lens 100 in the vicinity of the light emitting unit 31 of the light emitting element 3, the signal light emitted from the light emitting unit 31 is incident on the ball lens 100 and converged before it diverges widely. Therefore, for example, this embodiment is suitable when the light emitting element 3 having a high numerical aperture is used.

<Method for manufacturing optical waveguide module>
Next, an example of a method for manufacturing the optical waveguide module as described above will be described.

  An optical waveguide module 10 shown in FIG. 1 is manufactured by preparing an optical waveguide 1, a circuit board 2, a ball lens 100, a light emitting element 3, and a semiconductor element 4, and mounting them.

  Among these, the circuit board 2 is formed by forming a conductor layer so as to cover both surfaces of the insulating substrate 21 and then removing (patterning) unnecessary portions to leave the conductor layers 22 and 23 including the wiring pattern. The

  Examples of the method for producing the conductor layer include chemical vapor deposition methods such as plasma CVD, thermal CVD, and laser CVD, physical vapor deposition methods such as vacuum vapor deposition, sputtering, and ion plating, plating methods such as electrolytic plating and electroless plating, Examples include a thermal spraying method, a sol-gel method, and a MOD method.

  Moreover, as a patterning method of a conductor layer, the method which combined the photolithography method and the etching method is mentioned, for example.

Next, an example of a method for manufacturing an optical waveguide will be described.
The optical waveguide 1 has a laminated body (base material) formed by laminating a support film 18, a clad layer 11, a core layer 13, a clad layer 12 and a cover film 19 in this order from the lower side, and a part of the laminated body is removed. Thus, the mirror 16 is formed.

  Hereinafter, the manufacturing method of the optical waveguide will be described by dividing into [1] a step of forming a laminated body and [2] a step of forming the mirror 16.

  [1] Of the laminate (base material), the cladding layer 11, the core layer 13, and the cladding layer 12 are formed by sequentially forming the cladding layer 11, the core layer 13, and the cladding layer 12, or The clad layer 11, the core layer 13 and the clad layer 12 are formed on a base material in advance, and then manufactured by a method in which each of them is peeled off and bonded to the substrate.

  On the other hand, the support film 18 and the cover film 19 are manufactured by a method of bonding to the three layers manufactured as described above.

  Each of the clad layer 11, the core layer 13 and the clad layer 12 is formed by applying a composition for formation on a substrate to form a liquid film, and then homogenizing the liquid film and removing volatile components. It is formed.

  Examples of the coating method include a doctor blade method, a spin coating method, a dipping method, a table coating method, a spray method, an applicator method, a curtain coating method, and a die coating method.

  In order to remove volatile components in the liquid film, a method of heating the liquid film, placing the liquid film under reduced pressure, or spraying a dry gas is used.

  In addition, as a composition for formation of each layer, the solution (dispersion liquid) formed by melt | dissolving or disperse | distributing the constituent material of the clad layer 11, the core layer 13, or the clad layer 12 in various solvents is mentioned, for example.

  Here, examples of a method for forming the core portion 14 and the side clad portion 15 in the core layer 13 include a photobleaching method, a photolithography method, a direct exposure method, a nanoimprinting method, and a monomer diffusion method. It is done. In any of these methods, the refractive index of the core layer 13 is relatively different from that of the core portion 14 having a relatively high refractive index by changing the refractive index of the partial region of the core layer 13 or changing the composition of the partial region. A side cladding portion 15 having a low height can be formed.

  [2] Next, a digging process for removing a part from the lower surface side of the support film 18 is performed on the laminate. The inner wall surface of the space (cavity) thus obtained becomes the mirror 16.

The digging process on the stacked body can be performed by, for example, a laser processing method, a dicing method using a dicing saw, or the like.
The optical waveguide 1 is obtained as described above.

  FIG. 7 is a view (longitudinal sectional view) for explaining a method of manufacturing the optical waveguide module shown in FIG.

  Hereinafter, the method of manufacturing the optical waveguide module is divided into [1] a process of placing the ball lens 100 between the optical waveguide 1 and the circuit board 2 and [2] a process of mounting the light emitting element 3 and the semiconductor element 4. I will explain.

  [1] First, the circuit board 2 is prepared, and the ball lens 100 is disposed in the opening 241 (see FIG. 7A).

  The arrangement method is not particularly limited. For example, the circuit board 2 is arranged so that the opening 241 faces vertically upward, a large number of ball lenses 100 are supplied onto the circuit board 2, and the circuit board 2 is dropped into the opening 241. A method of reducing the pressure on the side of the opening 242 and sucking the ball lens 100 into the through hole 24 according to a pressure difference from the side of the opening 241 is used.

  Among these, in the former method, when the ball lens 100 is supplied onto the circuit board 2, the ball lens 100 moves while rolling on the circuit board 2. Thereafter, the circuit board 2 is swung as necessary, and the ball lens 100 is rolled. As a result, one ball lens 100 falls into the opening 241 after a predetermined time has elapsed.

  On the other hand, the latter method has an advantage that the orientation of the circuit board 2 is not limited because the ball lens 100 is disposed by the suction force accompanying the pressure difference. Further, since the ball lens 100 is pressure-bonded to the inner surface of the through hole 24 by the suction force, the position of the ball lens 100 in the through hole 24 can be accurately guided.

  Thereafter, the ball lens 100 is fixed in the through hole 24 as necessary. Examples of the fixing method include adhesion with an adhesive or a pressure-sensitive adhesive, thermocompression bonding, and fusion.

  [2] Next, the circuit board 2 is laminated on the optical waveguide 1 using an adhesive (see FIG. 7B). Then, the light emitting element 3 and the semiconductor element 4 are mounted on the circuit board 2 (see FIG. 7C). The optical waveguide module 10 is efficiently manufactured as described above.

<Electronic equipment>
The electronic device (the electronic device of the present invention) including the optical waveguide module of the present invention can be applied to any electronic device that performs signal processing of both an optical signal and an electric signal. For example, a router device, a WDM device, Application to electronic devices such as mobile phones, game machines, personal computers, televisions, home servers, etc. is preferable. 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, since such an electronic device includes the optical waveguide module of the present invention, problems such as noise and signal degradation peculiar to the electric 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. Therefore, the degree of integration in the substrate can be increased to reduce the size, the power required for cooling can be reduced, and the power consumption of the entire electronic device can be reduced.

  As described above, the embodiments of the optical waveguide module and the electronic device of the present invention have been described. However, the present invention is not limited to this, and for example, each part constituting the optical waveguide module is an arbitrary one that can exhibit the same function. It can be replaced with the configuration of Moreover, arbitrary components may be added, and a plurality of embodiments may be combined.

  Moreover, in each said embodiment, although the number of the channels (core part) which the optical waveguide 1 has is one, the number of channels may be two or more in the optical waveguide module of this invention. In this case, the number of mirrors, ball lenses, light emitting elements, light receiving elements, etc. may be set according to the number of channels. As for the light emitting element and the light receiving element, one element having a plurality of light emitting units or a plurality of light receiving units may be used.

DESCRIPTION OF SYMBOLS 1 Optical waveguide 10 Optical waveguide module 11 Clad layer (1st clad layer)
12 Cladding layer (second cladding layer)
DESCRIPTION OF SYMBOLS 13 Core layer 14 Core part 15 Side surface clad part 16 Mirror 18 Support film 19 Cover film 2 Circuit board 20 Connector 21 Insulating board 22, 23 Conductive layer 221,231 Opening part 222,232 Air gap 24 Through-hole 241,242 Opening 3 Light emission Element 31 Light emitting part 32 Electrode 4 Semiconductor element 42 Electrode 5 Adhesive layer 7 Light receiving element 71 Light receiving part 100 Ball lens

Claims (9)

A core part, a clad part provided so as to cover a side surface of the core part, and an optical path conversion part provided in the middle of the core part or on an extension line, for converting the optical path of the core part to the outside of the clad part And an optical waveguide comprising:
An optical element provided outside the cladding,
A substrate provided between the optical waveguide and the optical element, and having a through-hole formed along an optical path connecting the optical path conversion unit and the optical element, and
The through hole is configured such that a cross-sectional area gradually expands or contracts along the optical path,
An optical waveguide module comprising a substantially spherical ball lens having at least a portion inserted into the through hole.   2. The optical waveguide module according to claim 1, wherein at least half of the diameter of the ball lens is inserted into the through hole.   3. The optical waveguide module according to claim 1, wherein, of the two openings of the through hole, an opening having a smaller area cannot be passed through the ball lens.   The optical waveguide module according to any one of claims 1 to 3, wherein the through hole is configured so that a cross-sectional area continuously expands toward the optical waveguide side.   The optical waveguide module according to claim 4, wherein the ball lens is fixed to the optical waveguide through an adhesive and is in contact with an inner surface of the through hole.   The optical waveguide module according to any one of claims 1 to 3, wherein the through hole is configured so that a cross-sectional area continuously decreases toward the optical waveguide side.   The optical waveguide module according to any one of claims 1 to 6, wherein the focal point of the ball lens is positioned in at least one of the vicinity of the optical path changing unit and the vicinity of the light receiving and emitting unit of the optical element.   The optical waveguide module according to any one of claims 1 to 7, wherein the ball lens is made of any one of a resin material, a glass material, and a crystal material.   An electronic apparatus comprising the optical waveguide module according to claim 1.

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