JP2008122741A - Substrate for optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for an optical element such that transmission loss of an optical path is small and an electronic component which should be mounted is easily sealed. <P>SOLUTION: The substrate 1 for an optical element is made of a resin-made molding (s) having a top surface 2(2b) where the optical element 24 is mounted and a reverse surface 3, and has a plurality of insertion grooves 10 for optical fibers 20 formed on the top surface 2(2c) of the molding (s) and a light reflecting surface 8 which is disposed at one-end sides of the plurality of insertion grooves 10 and tilts as it spreads toward the top surface side 2b of the molding (s), where a recessed groove 14 where an electronic component 26 electrically connected to the optical element 24 to be mounted is mounted is formed on the side of the top surfaces 2a and 2b of the molding (s) on the opposite side from the insertion grooves 10 for the optical fibers 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical element substrate that has a small optical path transmission loss and can easily seal an optical element or electronic component to be mounted.

  Conventionally, in order to provide an optical transmission module that is excellent in productivity and inexpensive while ensuring alignment accuracy of an optical fiber used for optical communication, a light reflecting surface, and an optical element, the fixing groove and the optical path of the optical fiber are converted. In manufacturing an optical fiber holding member having an inclined reflecting surface, a semiconductor process and a method of performing anisotropic etching on a crystal substrate having a predetermined orientation have been proposed (for example, see Patent Document 1).

Japanese Patent No. 3677348 (pages 1 to 12, FIGS. 1 to 5)

As described in Patent Document 1, when a crystal substrate is anisotropically etched to form a light reflecting surface having a substantially V-shaped cross section, the crystal orientation of the substrate is used while high-precision processing is possible. Therefore, the shape to be formed is restricted. In addition, since anisotropic etching requires an etching mask made of silicon oxide or the like, there is a problem in that the productivity can be reduced.
Further, the coupling ratio of the optical path between the optical fiber fixed in the fixing groove of the manufactured optical fiber holding member and the optical element mounted on the holding member with the light reflection surface interposed therebetween is determined from the end face of the optical fiber to the optical element. Since it greatly depends on the distance to the light emitting / receiving surface, there is a problem that if there is a positional deviation in the optical path direction, transmission loss of the optical signal is caused.
Furthermore, since optical elements and electronic components to be mounted protrude on the surface of the optical transmission module, it is difficult to seal them from the outside, and there is a risk of damage due to inadvertent external force. There was also a problem.

  An object of the present invention is to solve the problems described in the background art, and to provide an optical element substrate in which an optical path transmission loss is small and an electronic component to be mounted can be easily sealed.

Means for Solving the Problems and Effects of the Invention

In order to solve the above-described problems, the present invention provides an optical element substrate having an optical fiber insertion groove and a light reflecting surface for converting an optical path, and an optical element substrate for mounting an optical element and an electronic component. It was conceived by applying the integrally molded body.
That is, the substrate for optical elements of the present invention is composed of a resin molded body having a front surface and a back surface on which the optical element is mounted, and a plurality of optical fiber insertion grooves opened on the surface of the molded body. A light reflecting surface that is located at one end of each insertion groove and that is inclined so as to spread toward the surface side of the molded body, and is opposite to the insertion groove for the optical fiber with respect to the light reflecting surface. On the surface side of the above-mentioned molded body located in the step, a concave groove or a concave portion for mounting an electronic component that conducts with an optical element to be mounted is formed.

  Since the optical element substrate is a resin molded body that can be collectively manufactured by an injection mold, the productivity is high and the positional accuracy is equivalent to that of a conventional optical fiber holding member obtained by anisotropic etching of a crystal substrate. In addition, since there is no restriction due to crystal orientation, the degree of freedom regarding the shape and the overall arrangement is remarkably increased. Furthermore, since the light reflection surface is located at one end of each insertion groove, the end surface of the optical fiber can be easily brought close to the light reflection surface by inserting the optical fiber into the insertion groove. For this reason, it becomes possible to reduce the transmission loss of an optical signal compared with the optical fiber holding member which anisotropically etched the conventional crystal substrate. Therefore, the optical fiber and the light reflecting surface can be accurately aligned with high accuracy, and the electronic component mounted on the surface side can be easily sealed with the sealing resin.

The insertion groove for the optical fiber has a substantially V-shaped cross section (for example, the bottom angle is 60 degrees) formed by a pair of symmetrical inclined surfaces, or between a pair of symmetrical inclined surfaces or vertical wall surfaces and their bottom sides. A substantially U-shaped configuration with a horizontal flat surface is also included.
Further, the light reflecting surface may be in the form of an inclination angle of 45 degrees, an inclination angle of 60 degrees or 30 degrees, and an inclination angle between these, for example, with respect to the surface.
Further, the concave groove is substantially along the longitudinal direction of the reflecting surface, and has a vertical surface standing from both sides of the flat bottom surface toward the surface, as well as from both sides of the flat bottom surface to the surface. The form which has the inclined surface which spreads toward is also contained.
The concave portion (cavity) includes not only a form having a vertical surface standing from the periphery of the flat bottom surface toward the surface, but also a form having an inclined surface extending from the periphery of the flat bottom surface toward the surface. It is.
Further, a step portion located on the reflection surface side may be formed on the surface between the groove or the recess and the reflection surface, and an optical element may be mounted on the horizontal surface of the step portion. In this case, the optical element mounted on the step portion can be easily sealed.
In addition, the optical element refers to any of a light emitting element, a light receiving element, and a light receiving / emitting element.

Moreover, a thermosetting resin or a thermoplastic resin is used for the resin of the molded body.
Examples of the thermosetting resin include epoxy resins (cresol novolac type, phenol novolac type, bisphenol type, biphenyl type, gincopentadiene type, naphthalene type, etc.) and phenolic resins.
On the other hand, the thermoplastic resin includes polystyrene, polyamide, polyacetal, polycarbonate, polybutylene / terephthalate, polyethylene / terephthalate, polyphenylene / ether, polyethersulfone / polysulfone, polyether / etherketone. , Polyphenylene sulfide, polymethylpentene, polytetrafluoroethylene, polycyclohexylenedimethyl terephthalate resin, liquid crystal polymer, and the like.
Furthermore, what added inorganic fillers, such as a silica which suppresses a thermal expansion coefficient with respect to said each resin material, is also contained.

Further, the present invention includes an optical element substrate in which the light reflecting surface is a part of a reflecting groove formed on the surface at a right angle in a plan view with respect to the optical fiber insertion groove. .
According to this, a plurality of optical elements having a plurality of optical fibers inserted into a plurality of insertion grooves and a light receiving / emitting surface corresponding thereto, or a single light having a plurality of light receiving / emitting surfaces. It is possible to reliably form a light reflecting surface in which the optical path direction is not displaced with respect to the element. For this reason, transmission loss can be further reduced.

The reflection groove has a substantially V-shaped cross section (for example, an angle of the bottom portion of 90 degrees) composed of a light reflection surface having an inclination angle of 45 degrees with respect to the surface and an inclined surface symmetrical to the light reflection surface. It includes a substantially letter-shaped cross section composed of a light reflecting surface and a vertical surface with an inclination angle of 45 degrees to 60 degrees with respect to the surface.
In other words, a fiber stop surface perpendicular to the surface and perpendicular to the surface is located at one end of each of the insertion grooves for the plurality of optical fibers, and the upper side of the fiber stop surface and the lowest part of the reflection groove are It is also possible to use a substrate for optical elements in substantially the same position.
In this case, since the fiber stop surface is located at one end of each of the insertion grooves, the optical fiber can be accurately mounted at a predetermined position simply by inserting the optical fiber into the insertion groove and abutting the end surface against the stop surface. Easy to do.

Further, in the present invention, the surface of the molded body located on the opposite side of the optical fiber insertion groove across the light reflection surface or the reflection groove including the light reflection surface includes the light reflection surface or the same. A first surface wiring for conducting the optical element to be mounted above the light reflecting groove and an electronic component to be mounted in the groove or recess, and a second surface for conducting the electronic component and an external wiring Also included is an optical element substrate on which wiring is formed.
According to this, the optical signal transmitted through the optical fiber is reflected by the light reflecting surface, taken into the optical element from the light receiving / emitting surface, converted into an electric signal, and then the first surface wiring is routed. Then, after being adjusted to a required electrical characteristic, it is transmitted to the external wiring via the second surface wiring. On the other hand, the electrical signal transmitted from the external wiring is converted into an optical signal through a path opposite to that described above, reflected by the light reflecting surface, and then transmitted through the optical fiber. Accordingly, communication between long distances can be performed using optical signals, and communication between short distances using electrical signals can be accurately performed.

The optical element substrate has a posture in which the surface side on which an electronic component such as an IC chip is mounted in the concave groove or the concave portion is a bottom surface, and the connection wiring (external wiring) of the wiring substrate and the second surface It is possible to fill and solidify a sealing resin between the wiring board and the optical element that is electrically connected to the wiring through solder and is mounted on the stepped portion. As a result, the mounted optical element and electronic component can be protected, and the positional relationship among the optical element, the light reflecting surface, and the optical fiber can be easily maintained. It becomes possible.
In addition, the first and second surface wirings have the insertion groove, the light reflection surface, a concave groove, and the like by being preset at a predetermined position on the inner surface of the mold when the molded body is injection molded. At the same time as molding the molded body, it can be placed on the surface of the molded body.

In the following, the best mode for carrying out the present invention will be described.
FIG. 1 is a perspective view showing an optical element substrate 1 according to one embodiment of the present invention, and FIG. 2 is a side view thereof.
The optical element substrate 1 is mainly composed of, for example, an integrally molded body s made of an epoxy resin, and as shown in FIGS. 1 and 2, the entire surface having a front surface 2 and a back surface 3 has a substantially plate shape. Yes. The surface 2 of the molded body s is rectangular in plan view, and has three surfaces 2a, 2b, 2c sandwiching the reflection groove 6 and the concave groove 14 along the direction perpendicular to the longitudinal direction of the surface 2 in the middle. It is divided into The front surfaces 2a and 2b are located slightly higher from the back surface 3 side than the front surface 2c.
In FIG. 1 and FIG. 2, four (a plurality of) optical fiber insertion grooves 10 having a substantially V-shaped cross-section opening on the surface 2 c are formed in parallel on the right surface 2 c. The insertion groove 10 includes a pair of inclined surfaces 11 inclined symmetrically by 60 degrees with respect to the surface 2c. In addition, a support portion 5 for a fiber whose upper surface is substantially the same height as the lowest portion of each insertion groove 10 extends on the outer side (right side) of the surface 2c including the four insertion grooves 10.

  As shown in FIGS. 1 and 2, an inverted triangular fiber stop surface 12 standing vertically from the lowest part of the pair of inclined surfaces 11 is located at one end (back end) of each of the four insertion grooves 10. ing. The reflection groove 6 includes a light reflection surface 8 and an inclined surface 7 that are inclined symmetrically by 45 degrees so as to spread toward the surfaces 2b and 2c. The lowest part of the reflection groove 6 is higher than the lowest part of the four insertion grooves 10. Therefore, the fiber stop surface 12 having a height corresponding to the difference in height is formed between the lowest part of the reflection groove 6 and the lowest part of each insertion groove 10. Furthermore, the upper half of one end of each insertion groove 10 is opened on the inclined surface 7 of the reflection groove 6.

As shown in FIGS. 1 and 2, a horizontal step 9 is located between the light reflecting surface 8 and the surface 2 b of the reflecting groove 6. In addition, the optical element 24 mentioned later is mounted in this step part 9. FIG.
Further, the concave groove 14 located between the surfaces 2 a and 2 b is composed of a horizontal bottom surface along the longitudinal direction of the reflection groove 6 and a pair of symmetrical inclined surfaces 15. A plurality of first surface wirings 18 are formed in parallel with each other and in a substantially hat shape across the concave groove 14, the surface 2 b, and the step portion 9. On the other hand, a plurality of second surface wirings 19 are formed in parallel from the concave groove 14 toward the surface 2a. The second surface wiring 19 is used for electrical connection with an external wiring described later, and one end thereof reaches the vicinity of the upper side of the side surface (end surface) 4 of the molded body s adjacent to the surface 2a.
An IC chip (electronic component) 26 (described later) connected across the first and second surface wirings 18 and 19 is mounted in the concave groove 14. Further, since the first and second surface wirings 18 and 19 pass through the inclined surface 15 and the inclined surface on the stepped portion 9 side, it is possible to reduce the return loss of the electrical signal that conducts them.

FIG. 3 is a perspective view showing an optical element substrate 1a of a different form, and FIG. 4 is a side view thereof. The optical element substrate 1a is also mainly composed of an integral molded body sa made of the same epoxy resin as described above, and the whole having the front surface 2 and the back surface 3 has a substantially plate shape as shown in FIGS. ing. The surface 2 of the molded body sa has a rectangular shape in plan view, and is divided into three surfaces 2a, 2b, and 2c with a reflection groove 6 and a recess 16 perpendicular to the longitudinal direction of the surface 2 interposed therebetween. . The surfaces 2a and 2b are continuous on both sides of the recess 16 along the longitudinal direction of the surface 2 as shown in FIG.
The optical element substrate 1 a is different from the optical element substrate 1 in that a concave portion (cavity) 16 is provided instead of the concave groove 14. The recess 16 includes a horizontal bottom surface, a pair of the inclined surfaces 15 and a pair of vertical surfaces 17 facing each other on the bottom surface. If the vertical surface 17 is an inclined surface similar to the inclined surface 15, the return loss of the wiring formed on the surface can be reduced.
As shown in FIGS. 3 and 4, a plurality of first surface wirings 18 are formed in the same manner as described above across the recess 16, the surface 2 b, and the stepped portion 9. On the other hand, a plurality of second surface wirings 19 are formed in the same manner as described above from the recess 16 along the surface 2a.

The optical element substrates 1 and 1a made of the molded bodies s and sa having the shapes (structures) as described above and having the surface wirings 18 and 19 are manufactured as follows.
A convex surface corresponding to the surface 2a, 2b, 2c, such as a convex shape corresponding to the reflection groove 6, the optical fiber insertion groove 10, and the fiber stop surface 12, and a convex corresponding to the concave groove 14 or the concave portion 16 in advance. A lower die having an inner surface including a part and a side surface corresponding to the side surface 4 and an upper die having an inner surface including a flat surface corresponding to the back surface 3 are manufactured by die processing. Shallow dents for accommodating the first and second surface wirings 18 and 19 are formed in portions corresponding to the vicinity of the surfaces 2a and 2b on the flat surface of the lower mold.
Next, after accommodating the first and second surface wirings 18 and 19 made of a copper alloy thin plate (copper foil) in each recess of the lower mold, the upper mold is set on the first and second surface wirings 18 and 19, and the mold is closed. In this state, the epoxy resin melted from the gate between the upper and lower molds is injection-molded into the mold. As a result, it is possible to obtain the optical element substrates 1, 1 a made of the molded bodies s, sa having the shapes as shown in FIGS. 1 to 4 and having the surface wirings 18, 19.
The first and second surface wirings 18 and 19 may be formed by performing thin film processing including patterning and etching on the surfaces of the molded bodies s and sa molded by the resin.

In the following, the method of using the optical element substrate 1 will be described as an example.
5 and 6 show a state in which the optical fiber 20 is inserted into the insertion groove 10 of the optical element substrate 1. The optical fiber 20 is a glass wire having a circular cross section made of quartz glass, and includes a core 22 having a high refractive index along a central portion and a clad 21 having a low refractive index surrounding the periphery of the core 22. Is transmitted along the axial direction in the core 22.
As shown by the arrows in FIGS. 5 and 6, the optical fiber 20 is inserted along the axial direction from the support portion 5 side for each insertion groove 10 of the optical element substrate 1. The outer diameter of the optical fiber 20 is substantially equal to the width of the intermediate position between the pair of inclined surfaces 11 and 11 in the insertion groove 10 and is substantially the same as or slightly smaller in depth than the insertion groove 10.

As shown in FIG. 6, the tip end surface of the optical fiber 20 cut in advance at an angle orthogonal to the axial direction is such that the lower portion of the clad 21 abuts against the fiber stop surface 12 located at one end (back end) of the insertion groove 10. Stop. At this time, the core 22 exposed at the distal end surface of the optical fiber 20 is located immediately above the fiber stop surface 12, enters the insertion groove 6 from the inclined surface 7, and reaches a position near the center thereof. In this state, an adhesive (not shown) is applied between the clad 21 of the optical fiber 20 and the inclined surface 11 of the insertion groove 10 to fix the position of the optical fiber 20.
As a result, as shown in FIG. 6, the four optical fibers 20 are positioned with the lower end of the tip surface in surface contact with the fiber stop surface 12 of each insertion groove 10 and positioned near the center of the reflection groove 6. The core 22 on the leading end face faces the light reflecting surface 8 while being closest.

Next, as shown in FIG. 7, a plurality of pads 23 are individually formed on each surface wiring 18 on the step portion 9, and the optical element 24 is interposed over these via a brazing material (not shown). Mount. A plurality of light receiving / emitting surfaces (not shown) exposed on the bottom surface of the optical element 24 are located immediately above the light reflecting surface 8. For this reason, as indicated by the arrows in FIG. 7, the optical signal transmitted through the core 22 of the optical fiber 20 is reflected at a right angle by the light reflecting surface 8 and rises vertically. Enter 24. The direction of the optical path is less likely to be misaligned by the four optical fibers 20 and the light reflecting surfaces 8 that are accurately positioned by the fiber stop surface 12 for each insertion groove 10.
The optical element 24 is a substantially rectangular parallelepiped having a rectangular shape in a plan view along the longitudinal direction of the reflection groove 6, and four (a plurality) of optical / electrical conversion elements are incorporated therein. The upper surface of the optical element 24 is substantially flush with the surfaces 2a and 2b of the molded body s. .

As shown in FIG. 7, an IC chip (electronic component) 26 is mounted via solder 25 across the first and second surface wirings 18 and 19 on the bottom surface of the groove 14. The IC chip 26 performs control such as increasing the electric signal converted by the optical element 24 to a predetermined voltage, and transmits the electric signal to the outside through the surface wiring 19 and converts the electric signal transmitted from the outside into an optical signal. It works to control the electrical characteristics that are easy to do. Note that the upper surface of the IC chip 26 is substantially flush with the surfaces 2a and 2b.
Thereby, the optical element 24 and the IC chip 26 are electrically connected to each other via the first surface wiring 18, and they are also electrically connected to the second surface wiring 19.
That is, the optical signals emitted from the front end surfaces of the four optical fibers 20 are reflected at a right angle by the light reflecting surface 8, converted into an electrical signal by the optical element 24, and passed through the first surface wiring 19 to the IC chip 26. After being controlled to be increased to a predetermined voltage at, it is output to the outside through the second surface wiring 19.

On the other hand, the electrical signal transmitted from the outside through the surface wiring 19 is adjusted to a required electrical characteristic in the IC chip 26, sent to the optical element 24 through the surface wiring 18 and converted into an optical signal, and then the light emitting surface. Then, the light is emitted vertically downward, reflected by the light reflecting surface 8 in a horizontal direction perpendicular to the light, and then transmitted through the core 22 of the optical fiber 20 that is closest.
As shown in FIGS. 1 and 3, the first surface wiring 18 corresponds to each of the four optical fibers 20, so that the total number is doubled to eight. The number of second surface wirings 19 is also the same.
Further, the insertion / fixation of the optical fiber 20 as described above and the mounting of the optical element 24 and the IC chip 26 are performed in the same manner for the optical element substrate 1a having the recess 16, and the same action as described above. Can be made.

  According to the optical element substrates 1 and 1a as described above, a plurality (four) of optical fiber insertion grooves 10 are formed on the surface 2c of the resin molded bodies s and sa, and one end thereof is formed. The vertical fiber stop surface 12 is positioned, and one end of the vertical fiber stop surface 12 is opened in the reflection groove 6 orthogonal to the insertion groove 10. For this reason, when the optical fiber 20 is inserted into the insertion groove 10 from the support portion 5 side, the lower coating portion 21 on the tip surface thereof comes into surface contact with the fiber stop surface 12 and stops at this position. The exposed core 22 is exposed inside the reflecting groove 6 and is closest to the light reflecting surface 8. As a result, the optical element 24 mounted above the light reflecting surface 8 is less likely to be displaced in the optical path direction and an accurate optical path can be formed, so that transmission loss can be reduced.

Furthermore, since the IC chip 26 is mounted in the concave groove 14 or the concave portion 16 and the optical element 24 is mounted in the stepped portion 9, it is possible to prevent inadvertent damage due to external force and to facilitate sealing described later. . Moreover, the molded body s, sa having the reflection groove 6, the insertion groove 10, the fiber stop surface 12, and the concave groove 14 or the concave portion 16 has high shape and dimensional accuracy by injection molding with an epoxy resin or the like, and has a conventional crystal structure. It can be manufactured efficiently and inexpensively compared to the substrate.
Therefore, according to the optical element substrates 1 and 1a, the optical fiber 20, the light reflecting surface 8, and the optical element 24 to be mounted can be accurately and reliably aligned, and the loss due to the optical signal misalignment or signal degradation. The IC chip 26 and the optical element 24 can be easily protected or sealed, and can be manufactured and provided at a low cost.

FIG. 8 is a perspective view showing a wiring board 30 using the optical element substrate 1 (1a).
The wiring substrate 30 is made of resin or ceramic, and integrally includes a substrate body 31 having a front surface 32 and a back surface 33, and a support portion 35 extending horizontally outward from one side along the back surface 33 side. ing. A mounting area for an electronic component (for example, LSI) 40 is located at the center of the surface 32 of the substrate body 31. Two sets of connection wirings 36a and 36b are formed between the mounting area and one side facing the support portion 35 side. Each of the connection wirings 36 a and 36 b is composed of six parallel wirings, and is electrically connected via an electrode (not shown) protruding from the bottom surface of the electronic component 40 and solder. The substrate body 31 is a multilayer substrate, and has a wiring layer with a required pattern (not shown) inside. The wiring layer can be electrically connected to pads (not shown) located on the front surface 32 and the back surface 33. Yes.

As shown in FIG. 8, the front and rear two optical element substrates 1 (1a) are fixed to the upper surface of the support portion 35 via an underfill material. In the optical element substrate 1 (1a), as described above, the optical fiber 20 is inserted and fixed in the insertion groove 10 on the surface 2c side, and the optical element 24 and the IC chip 26 are inserted in the recesses 14 on the surface 2a, 2b side. Has been implemented.
As shown in FIG. 8, the two optical element substrates 1 (1 a) mounted on the upper surface of the support portion 35 of the wiring substrate 30 are connected to the surface wiring 19 and the connection wiring 36 a on the surface 32 side of the wiring substrate 30. , 36b are individually connected via bonding wires w. At this time, for example, the front optical element substrate 1 (1a) in FIG. 8 may be used for reception, and the rear optical element substrate 1 (1a) in FIG. 8 may be used for transmission.

According to the wiring board 30 as described above, the optical signal transmitted from the optical fiber 20 of the receiving optical element substrate 1 (1 a) located on the near side in FIG. 8 is converted into an electrical signal by the optical element 24. Then, it is transmitted to the electronic component 40 mounted at the center of the surface 32 through the IC chip 26, the surface wiring 19, and the connection wiring 36a, and undergoes a required process.
On the other hand, the electrical signal transmitted from the electronic component 40 is transmitted to the optical element 24 via the connection wiring 36b, the surface wiring 19 of the optical element substrate 1 (1a) on the back side in FIG. After being converted into an optical signal, it is transmitted through the optical fiber 20 to the outside.

For this reason, the transmission loss of the optical signal can be reduced, and the converted electrical signal can be accurately received, and the transmission loss of the optical signal converted from the electrical signal can be reduced and transmitted to the outside. Therefore, for example, transmission of signals between long distances can be performed through the optical fiber 20 with reduced transmission loss, and required operations and processing can be accurately executed based on the converted and adjusted electrical signals. It becomes possible. In addition, since the IC chip 26 is mounted in the concave groove 14 and the optical element 24 is mounted on the stepped portion 9, it can be stably operated without being inadvertently damaged.
In place of the optical element substrate 1, the optical element substrate 1a may be used in the same manner. Alternatively, only one optical element substrate 1 (1a) may be used for the wiring substrate 30, and two optical fibers 20 may be used separately for reception and transmission.

FIG. 9 is a partial cross-sectional view in which the optical element substrate 1 (1 a) is used in a different manner with respect to the wiring substrate 30. A plurality of external terminals (external wirings) 37 that are electrically connected to a wiring layer (not shown) in the substrate body 31 extend on the upper surface of the support portion 35 of the wiring board 30.
In the optical element substrate 1 (1a), in the same manner as described above, the optical fiber 20 is inserted and fixed in the insertion groove 10 on the surface 2c side, and the optical element 24 and the step portion 9 or the concave portion 14 on the surface 2a, 2b side. An IC chip 26 is mounted.
As shown in FIG. 9, the optical element substrate 1 (1 a) is turned upside down, and the second surface wiring 19 and the external terminal 37 facing vertically are connected via a solder 38. Note that the first surface wiring 18 and the external terminal 37 located on the center side of the support portion 35 may be directly connected via a solder 38 as shown in the figure.

Next, as shown in FIG. 9, for example, an epoxy-based sealing resin (light-emitting element) is formed in the gap between the support portion 35 of the wiring substrate 30 facing the surface 2 a, 2 b, 2 c of the optical element substrate 1 (1 a). The underfill material for transmission) 39 is filled and solidified. As a result, the optical fiber 20, the optical element 24, and the IC chip 26 are fixed in position by the sealing resin 39 and simultaneously sealed from the outside.
As a result, the mounted optical element 24 and IC chip 26 can be sealed from the outside, and the positional relationship among the optical element 24, the light reflecting surface 8, and the optical fiber 20 can be easily maintained. Can be prevented over a long period of time.
Therefore, by using the optical element substrate 1 (1a) as described above, it is possible to further stabilize the reception / transmission of optical signals and the reception / transmission of electrical signals in the wiring substrate 30. Instead of the optical element substrate 1, the optical element substrate 1a may be used for the wiring substrate 30 as shown in FIG.

The present invention is not limited to the embodiments described above.
The molded body constituting the optical element substrate may be made of a thermosetting resin other than the epoxy resin or a thermoplastic resin such as a polyamide resin.
The insertion groove for the optical fiber has a pair of inclined surfaces and a horizontal bottom surface between these bottoms, or a cross section composed of a pair of vertical side walls and a bottom surface between these bottoms. It is good also as a substantially U-shaped form. In these cases, a substantially trapezoidal or rectangular fiber stop surface is formed on the bottom side at one end of the insertion groove.
Furthermore, the light reflection surface (8) of the light reflection groove may have an arbitrary inclination within a range of 30 degrees to 60 degrees with respect to the surface 2 (2b) of the optical element substrate.
In addition, the reflection groove may have a substantially letter-shaped cross section including an inclined light reflection surface and a vertical surface erected vertically from the bottom.
Further, the step portion (9) and the bottom surface of the concave groove (14) or the concave portion (16) may have the same height from the back surface (3) of the molded body (s, sa).
In addition, the upper surface of the support portion (5) of the optical element substrate is positioned lower on the back surface (3) side than the lowest portion of the optical fiber insertion groove (10). You may make it support the minimum part of the protective cover which covers the outer periphery of a coating | coated part (21). Or it is also possible to set it as the board | substrate for optical elements provided with the molded object (s, sa) which abbreviate | omitted the said support part (5).

The perspective view which shows the board | substrate for optical elements which is one form of this invention. The side view which shows the said board | substrate for optical elements. The perspective view which shows the board | substrate for optical elements of a different form. The side view which shows the said board | substrate for optical elements. The side view which shows the outline of the state which inserts an optical fiber in the board | substrate for optical elements of FIG. The side view which shows the said board | substrate for optical elements in which the optical fiber was inserted. Furthermore, the side view which shows the said board | substrate for optical elements in which the optical element etc. were mounted. The perspective view which shows the wiring board using the said board | substrate for optical elements. The fragmentary sectional view which shows the usage pattern from which the board | substrate for optical elements differs.

Explanation of symbols

1, 1a ............ Optical element substrate 2, 2a, 2b, 2c ... Front surface 3 …………………… Back surface 6 ………………………… Reflection groove 8… ……………………… Light reflecting surface 10 ……………………… Insertion groove 14 ……………………… Recess groove 16 ……………………… Recess 18 and 19 ……………… Surface wiring 20 ……………………… Optical fiber s, sa ………………… Molded body

Claims (3)

It consists of a resin molded body having a front surface and a back surface on which the optical element is mounted,
Insert grooves for a plurality of optical fibers formed on the surface of the molded body,
A light reflecting surface that is located at one end of each of the plurality of insertion grooves and is inclined so as to spread toward the surface side of the molded body,
On the surface side of the molded body located on the opposite side of the optical fiber insertion groove with respect to the light reflecting surface, a concave groove or a concave portion for mounting an electronic component that conducts with an optical element to be mounted is formed. Yes,
An optical element substrate characterized by the above. The light reflection surface is a part of a reflection groove formed on the surface at a right angle in a plan view with respect to the insertion groove for the optical fiber.
The optical element substrate according to claim 1. Mounted on the surface of the molded article located on the opposite side of the optical fiber insertion groove across the light reflection surface or the reflection groove including the light reflection surface or the reflection groove including the light reflection surface. A first surface wiring for conducting the optical element and the electronic component to be mounted in the concave groove or the concave portion, and a second surface wiring for conducting the electronic component and the external wiring are formed.
The optical element substrate according to claim 1, wherein the substrate is an optical element substrate.

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