JP2012220621A - Receiver module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a loss of optical coupling caused by mounting deviation and reduce a manufacturing cost.SOLUTION: A receiver module includes a light-receiving element 3, a substrate 2, and a resin layer 6 in which the light-receiving element 3 and the like are sealed. The resin layer 6 includes an optical path conversion part 10 in which first and second lens parts 11 and 12 are stacked, provided at a position covering the light-receiving element 3; and a fixing mechanism 7 for attaching an optical fiber 14 to the vicinity of the optical path conversion part 10 via a ferrule 13. The first lens part 11 has a first reflection surface 11A that is located on a lower side near the light-receiving element 3 and formed with a first curvature radius R1. Meanwhile, the second lens part 12 has a second reflection surface 12A that is located at an upper side distant from the light-receiving element 3 and formed with a second curvature radius R2 larger than the first curvature radius R1.

Description

  The present invention relates to a receiving module that receives an optical signal propagating in an optical fiber.

  In general, an optical module having an optical element and an optical waveguide on a support substrate is known (see, for example, Patent Document 1). In the optical module described in Patent Document 1, since the optical waveguide is bonded and fixed in a state parallel to the surface of the support substrate, it is necessary to perform a 90 ° optical path conversion between the optical element and the optical waveguide. . For this reason, the tip of the optical waveguide is cut at an inclination angle of 45 ° with respect to the support substrate, and this cut surface is made to function as a mirror for performing optical path conversion of 90 °. The optical element mounted on the support substrate is sealed with a transparent resin. In order to prevent the optical axis from shifting due to the shrinkage of the sealing resin during curing, a gap is formed between the optical waveguide and the sealing resin.

JP 2007-286289 A

  By the way, in the above-described prior art, since the tip of the optical waveguide is cut at an inclination angle of 45 °, it is necessary to accurately control the cut angle of the optical waveguide and the surface roughness of the cut surface. Cost tends to rise.

  In addition, since a gap is formed between the optical element and the optical waveguide, there is a possibility that a foreign matter that has entered the gap adheres to the surface of the sealing resin or the optical waveguide and a transmission error occurs. Furthermore, since no condensing component such as a lens is provided between the optical element and the optical waveguide, the optical coupling loss between the optical element and the optical waveguide increases due to the positional deviation of the optical element and the optical waveguide. There is also a problem.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a receiver module that can suppress a loss of optical coupling due to a positional deviation between a light receiving element and an optical waveguide and reduce manufacturing costs. It is to provide.

  In order to solve the above-described problem, the invention of claim 1 includes a light receiving element, a substrate on which the light receiving element is mounted, and a resin layer that covers the surface of the substrate. A fixing mechanism having a surface opened and a recess for mounting a tip end of an optical fiber inserted through the ferrule from the opening, an extension direction of the ferrule via the first and second reflecting surfaces, and the light receiving element And an optical path conversion portion formed of an optically transparent resin material that matches the optical path of the first optical path. The optical path conversion portion includes a first reflection surface formed with a first radius of curvature. And a second lens portion having the second reflecting surface formed with a second radius of curvature larger than the first radius of curvature, and the lower surface of the second lens portion is On the outer periphery of the second reflecting surface and the upper surface of the first lens portion The first lens unit and the second lens unit are laminated so that the outer periphery of the first reflecting surface is inscribed, and the light emitted from the optical fiber is optically converted by the optical path conversion unit. Thus, the light is incident on the light receiving element.

  In the invention of claim 2, the outer periphery of the upper surface of the first lens portion and the second lens in the extending direction of the central axis of the optical fiber inserted through a ferrule mounted substantially horizontally with respect to the surface of the substrate The optical path changing part is formed so that an inner contact with the outer periphery of the lower surface of the part is located.

  According to the first aspect of the present invention, since the optical path changing unit is provided so as to cover the surface of the substrate, even when a light receiving element that receives an optical signal perpendicular to the substrate surface is used, The optical path of the optical signal can be easily converted so that the optical signal in the parallel direction is directed in the vertical direction. For this reason, the light receiving element can receive an optical signal from the optical fiber via the optical path changing unit.

  Moreover, since the resin layer having the fixing mechanism and the optical path changing portion is formed on the substrate surface in a state where the light receiving element is sealed, the bonding strength of the fixing mechanism to the substrate can be increased. Further, since the fixing mechanism and the optical path changing unit are integrally formed, the assembly process can be simplified and the manufacturing cost can be reduced. In addition, since the concave portion whose surface is opened is formed in the fixing mechanism, the ferrule through which the tip side of the optical fiber is inserted can be easily inserted into the concave portion and fixed to the concave portion.

  Furthermore, the light receiving element can be sealed inside the resin layer, and the optical fiber can be fixed to the fixing mechanism of the resin layer. At this time, since the optical signal from the optical fiber can be incident on the light receiving element through the transparent resin layer, there is no need to form a gap between the optical fiber and the light receiving element. For this reason, foreign matter does not adhere between the optical fiber and the light receiving element, and transmission errors can be prevented.

  In addition, since the optical path conversion unit is configured by laminating the first and second lens units having the first and second reflecting surfaces, the optical path conversion unit performs the optical path conversion at the same time as the first and first lens units. With the two reflecting surfaces, an optical signal from the optical fiber can be condensed toward the light receiving element. For this reason, even when mounting deviation occurs in the optical fiber and the light receiving element, loss of optical coupling due to this mounting deviation can be reduced.

  Further, the first lens portion has a first reflecting surface formed with a first radius of curvature, and the second lens portion is formed with a second radius of curvature larger than the first radius of curvature. It was set as the structure which has two reflective surfaces. For this reason, the 1st reflective surface can heighten the condensing effect | action condensed on a light receiving element by making 1st radius of curvature small. On the other hand, the second reflecting surface is formed with a second radius of curvature larger than the first radius of curvature. In the second lens unit, the size of the lens is increased in the height direction by the amount of curvature radius compared to the first lens unit. Therefore, even when the optical fiber is displaced in the height direction of the substrate so as to approach the second lens portion, more light can be condensed without leaking light out of the lens. As a result, even when the optical fiber is displaced in the height direction of the substrate, loss of optical coupling between the light receiving element and the optical fiber can be suppressed, and the influence of mounting deviation between the light receiving element and the optical fiber is reduced. can do.

  According to the second aspect of the present invention, the optical path conversion unit is arranged such that the inner contact point between the outer periphery of the upper surface of the first lens unit and the outer periphery of the lower surface of the second lens unit is located in the extending direction of the central axis of the optical fiber. Formed. For this reason, the area | region where the loss of each optical coupling in a 1st lens part and a 2nd lens part is small can be utilized efficiently.

It is a perspective view which shows the receiving module by the 1st Embodiment of this invention. It is a perspective view which shows the receiving module in FIG. 1 in the state which removed the optical fiber and the ferrule. It is a perspective view which shows the receiving module seen from the fixing mechanism side. It is a perspective view which shows the receiving module seen from the optical path conversion part side. It is a perspective view which expands and shows an optical path change part. It is a top view which shows a receiving module. It is sectional drawing which looked at the optical path conversion part, the light receiving element, the optical fiber, etc. from the arrow VII-VII direction in FIG. It is sectional drawing of the same position as FIG. 7 which shows the optical path changing part by a 1st comparative example. It is sectional drawing of the position similar to FIG. 7 which shows the optical path changing part by a 2nd comparative example. It is a characteristic diagram which shows the relationship between the deviation | shift amount of an optical fiber in the Z-axis direction, and the loss of optical coupling in the case of using the optical path change part by a 1st, 2nd comparative example and 1st Embodiment. In a 2nd comparative example, it is explanatory drawing which shows the state which has arrange | positioned the optical fiber to the upper part side of the optical path change part. In a 2nd comparative example, it is explanatory drawing which shows the state which has arrange | positioned the optical fiber to the lower part side of the optical path changing part. It is a perspective view which shows the receiving module by 2nd Embodiment. It is a perspective view shown in the state which decomposed | disassembled the receiving module in FIG. It is explanatory drawing which shows the state which takes out a receiving module from a parent board | substrate by a dicing process. It is a perspective view which shows the receiving module by 3rd Embodiment. It is a perspective view shown in the state which decomposed | disassembled the receiving module in FIG. It is a perspective view which shows the receiving module by a modification.

  Hereinafter, a receiving module according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  The receiving module 1 according to the first embodiment will be specifically described with reference to FIGS. 1 to 7. The receiving module 1 includes a resin layer 6 including a substrate 2, a light receiving element 3, a fixing mechanism 7, and an optical path changing unit 10.

  The substrate 2 is a rectangular flat plate formed using an insulating material. As the substrate 2, for example, a printed wiring board is used. On the surface of the substrate 2, a light receiving element 3, for example, a light receiving integrated circuit component 4 (hereinafter referred to as a limiting amplifier) for driving and controlling the light receiving element 3 and amplifying a detection signal from the light receiving element 3, for example, Various kinds of electronic components 5 such as resistors, capacitors, coils and the like are mounted. The light receiving element 3, the light receiving IC component 4 and the electronic component 5 are electrically connected to each other using bonding wires, wiring patterns, or the like.

  The light receiving element 3 is mounted on the surface corner of the substrate 2 so that the light receiving surface of the light receiving element 3 is parallel to the surface of the substrate 2 and is incident in a direction perpendicular to the surface of the substrate 2 (Z-axis direction). Receives infrared and visible light. As the light receiving element 3, for example, a photodiode (PD), a phototransistor or the like is used.

  The resin layer 6 in which the fixing mechanism 7 and the optical path changing unit 10 are integrally formed is formed on the surface of the substrate 2 by using a general molding method such as transfer molding or a simple method such as potting. The resin layer 6 is formed in a substantially rectangular parallelepiped shape that covers the entire surface of the substrate 2, and seals the light receiving element 3, the light receiving IC component 4, and the electronic component 5. The resin layer 6 is made of a resin material that is transparent to the light emitted from the optical fiber 14, that is, is capable of transmitting light and has a refractive index larger than that of air.

  The fixing mechanism 7 includes a fitting groove 8 as a concave portion and a locking portion 9 having locking protrusions 9A1 and 9A2.

  The fitting groove 8 is a groove formed on the short side edge of the resin layer 6 and extending from the vicinity of the light receiving element 3 to the opening 8 </ b> B provided on the long side surface of the resin layer 6. Note that the fitting groove 8 is a groove whose cross-sectional shape perpendicular to the extending direction (X-axis direction) of the fitting groove 8 is formed in a quadrangle and is located on the light receiving element 3 side and is substantially the same as the outer diameter of the ferrule 13. The fixed groove portion 8C having a width dimension and the guide groove portion 8D which is located on the opening 8B side and gradually increases in width as it approaches the opening 8B are configured. The fitting groove 8 has an opening 8 </ b> A on the upper surface of the resin layer 6. The ferrule 13 is mounted via the opening 8A on the upper surface of the resin layer 6 or from the opening 8B on the long side surface via the guide groove 8D.

  The locking projections 9A1 and 9A2 are obtained by projecting both wall surfaces sandwiching the fitting groove 8 inward. The locking projections 9A1 and 9A2 are arranged near the boundary position between the fixed groove 8C and the guide groove 8D in the fitting groove 8, for example. The ferrule 13 attached to the fitting groove 8 with its tip abutting against the closed end of the fixed groove 8C is held from both sides of the fitting groove 8 in the width direction by the locking projections 9A1 and 9A2. Thereby, the tip end side of the optical fiber 14 inserted through the ferrule 13 is locked in the fitting groove 8 together with the ferrule 13. Note that the tip side of the ferrule 13 is fixed in the fitting groove 8 using a transparent adhesive or the like. At this time, the end surface 14A of the optical fiber 14 is fixed using a transparent adhesive or the like in a state of contacting or facing the closed end of the fixing groove 8C.

  The locking portions 9 may be provided at a plurality of locations with respect to the extending direction of the fitting groove 8. Further, an annular groove may be formed on the outer peripheral side of the ferrule 13 so as to engage with the locking projections 9A1 and 9A2.

  The ferrule 13 is formed in a cylindrical shape by a metal material or a resin material, for example.

  In general, when the ferrule 13 and the optical fiber 14 are attached to the fitting groove 8, the tip end side of the optical fiber 14 is first attached to the ferrule 13, and the ferrule 13 is attached to the fitting groove 8 together with the optical fiber 14 in this state. Insert into. Then, the ferrule 13 and the optical fiber 14 are fixed to the fitting groove 8 using a transparent adhesive.

  However, it is not limited to this attachment method, and the tip end side of the optical fiber 14 may be inserted into the ferrule 13 after the ferrule 13 is attached to the fitting groove 8 in advance. In this case, a transparent adhesive is applied in the fitting groove 8 in advance, and only the ferrule 13 is attached in this state. Thereafter, the optical fiber 14 is inserted into the ferrule 13 and a transparent adhesive is additionally applied so that the entire ferrule 13 is covered. At this time, a transparent adhesive having a function of matching the refractive index is filled between the ferrule 13 and the optical fiber 14 so that no gap is formed between the tip of the ferrule 13 and the optical fiber 14 and the closed end of the fitting groove 8.

  The optical path conversion unit 10 includes dome-shaped first and second lens units 11 and 12 having curved surfaces exposed to the outside, and is provided so as to cover the light receiving element 3. The first and second lens portions 11 and 12 are stacked in a direction perpendicular to the surface of the substrate 2 (Z-axis direction), and the first lens portion 11 is disposed on the lower side near the light receiving element 3. Is done. At this time, the first lens unit is arranged such that the outer periphery of the second reflecting surface 12A on the lower surface of the second lens unit 12 and the outer periphery of the first reflecting surface 11A on the upper surface of the first lens unit 11 are inscribed. 11 and the second lens unit 12 are overlapped. Further, the outer periphery of the upper surface of the first lens portion 11 and the second end in the extending direction of the central axis (optical path Lr1) of the optical fiber 14 inserted into the ferrule 13 mounted substantially horizontally with respect to the surface of the substrate 2. The optical path conversion unit 10 is arranged and formed so that the inner contact 10A with the outer periphery of the lower surface of the lens unit 12 is located. Further, a common tangential plane T of the first lens unit 11 and the second lens unit 12 is inclined by, for example, approximately 45 ° with respect to the surface of the substrate 2. The first lens unit 11 has a first reflecting surface 11A formed with a first radius of curvature R1 of about several millimeters, for example, and its focal position is arranged around the light receiving element 3.

  Further, the second lens portion 12 has a second reflecting surface 12A formed with a second curvature radius R2 (R2> R1) larger than the first curvature radius R1. The second radius of curvature R2 is set to a value that is twice or more the first radius of curvature R1, for example.

  The optical signal emitted from the optical fiber 14 is reflected by the first and second reflecting surfaces 11 </ b> A and 12 </ b> A, and then condensed and enters the light receiving element 3. That is, the first and second reflecting surfaces 11A and 12A function not only as reflecting surfaces but also as lenses that collect optical signals on the light receiving element 3. Thus, the optical path conversion unit 10 matches the optical path Lr2 of the light receiving element 3 with the extending direction (X-axis direction) of the ferrule 13 and the optical fiber 14 via the first and second reflecting surfaces 11A and 12A.

  Next, propagation of the optical signal in the receiving module 1 according to the first embodiment will be specifically described.

  The optical signal propagated in the optical fiber 14 is emitted in the horizontal direction (X-axis direction) with respect to the surface of the substrate 2 from the end face 14 </ b> A of the optical fiber 14 and is input to the receiving module 1. The optical signal input to the receiving module 1 is optically path-converted in the vertical direction (Z-axis direction) with respect to the substrate 2 by the first and second reflecting surfaces 11A and 12A in the optical path converter 10, and is received by the light receiving element 3. Is done. The optical signal received by the light receiving element 3 is converted into an electric signal.

  Here, in the receiving module 1, a loss of optical coupling occurs between the light receiving element 3 and the optical fiber 14 due to the assembly accuracy and dimensional accuracy of components constituting the receiving module 1. Specifically, with respect to the light receiving element 3, mounting displacement occurs in the plane of the substrate 2. Further, with respect to the optical fiber 14, mounting displacement occurs in the parallel direction (XY plane) and the vertical direction (Z-axis direction) with respect to the surface of the substrate 2 due to the dimensional accuracy and assembly accuracy of the ferrule 13. For this reason, due to the relative displacement generated between the light receiving element 3 and the optical fiber 14, the light amount of the optical signal that has been output from the optical fiber 14 and is converted into an optical path and incident on the light receiving element 3 is changed. Loss occurs.

  In order to allow the relative displacement between the light receiving element 3 and the optical fiber 14, it is necessary that the change in the loss of optical coupling is small within the range of the predicted relative displacement. Therefore, from such a viewpoint, an optical simulation result on the shape of the optical path changing unit 10 is shown below.

  When the shape of the reflecting surface of the optical path changing unit 10 is changed, the most significant influence on the loss of optical coupling between the light receiving element 3 and the optical fiber 14 is in the thickness direction (Z-axis direction) of the substrate 2. It is confirmed by optical simulation that the displacement of the optical fiber 14, that is, the displacement in the direction in which the optical fiber 14 moves away from the substrate 2 (+ direction) and the direction in which the optical fiber 14 approaches the substrate 2 (− direction). For this reason, the shape of the reflection surface of the optical path conversion unit 10 was examined in consideration of the relative positional deviation between the light receiving element 3 and the optical fiber 14 in the thickness direction (Z-axis direction) of the substrate 2.

  First, as a first comparative example, as shown in FIG. 8, with respect to the optical path conversion unit 21 formed with the same first radius of curvature R1 as the first lens unit 11, the amount of deviation between the light receiving element 3 and the optical fiber 14 and the light The relationship with the loss of coupling was investigated. The result is shown by the broken line in FIG. FIG. 10 shows, as an example, the relationship between the shift amount and the optical coupling loss when the optical fiber 14 is displaced in the Z-axis direction.

  In the first comparative example, as shown by the broken line in FIG. 10, the optical coupling is greater when the amount of deviation of the optical fiber 14 in the Z-axis direction increases toward the minus side than when it increases toward the minus side. Loss tends to increase. That is, in FIG. 8, the optical coupling loss is lower when the optical fiber 14 is disposed on the lower side near the light receiving element 3 than when the optical fiber 14 is disposed on the upper side away from the light receiving element 3. . However, when the amount of deviation of the optical fiber 14 in the Z-axis direction increases to the plus side, the optical coupling loss greatly increases.

  Next, as a second comparative example, with respect to the optical path changing unit 22 formed with the same second radius of curvature R2 as the second lens unit 12 as shown in FIG. The relationship with the loss of optical coupling was investigated. The result is shown by the alternate long and short dash line in FIG.

  In the second comparative example, as shown by the one-dot chain line in FIG. 10, the optical coupling is greater when the amount of deviation of the optical fiber 14 in the Z-axis direction increases toward the plus side than when it increases toward the plus side. The loss tends to increase. That is, in FIG. 9, the optical coupling loss is lower when the optical fiber 14 is disposed on the upper side away from the light receiving element 3 than when the optical fiber 14 is disposed on the lower side near the light receiving element 3. . As described above, the characteristic of increasing the optical coupling loss varies depending on the radius of curvature and the direction in which the optical fiber 14 is displaced.

  The reason why the loss of the first comparative example is smaller than that of the second comparative example when the shift amount of the optical fiber 14 in the Z-axis direction is increased to the negative side is that the first comparative example is compared to the second comparative example. This is because the radius of curvature in the optical path changing unit is small. In FIG. 12, the light incident angle θ increases as the radius of curvature of the optical path changing unit decreases. At this time, when the incident angle θ is larger than the critical angle θc (θ> θc), total reflection occurs on the reflection surface of the optical path conversion unit, and there is no light that is refracted and leaks into the air. For this reason, as the incident angle θ increases, the total reflection component of the light in the optical path conversion unit increases and the light incident on the light receiving element 3 increases, thereby suppressing the loss of optical coupling. The critical angle θc is determined by the ratio between the refractive index of air and the refractive index of the transparent resin material in the optical path conversion section.

  The reason why the loss of the second comparative example is smaller than that of the first comparative example when the amount of deviation of the optical fiber 14 in the Z-axis direction is increased to the plus side is that the second comparative example has a smaller loss than the first comparative example. This is because the size of the optical path conversion unit = lens portion in the Z-axis direction is increased due to the large curvature radius in the optical path conversion unit of the comparative example. In FIG. 12, when the radius of curvature of the optical path changing unit is large, even when the optical fiber 14 is shifted to the plus side in the Z-axis direction, more light is received by the reflecting surface of the optical path changing unit, and the light receiving element 3 receives the light. Can be incident. On the other hand, if the radius of curvature of the optical path conversion unit is small, when the optical fiber 14 is displaced to the plus side in the Z-axis direction, light leaks into the air without entering the optical path conversion unit. As a result, the loss of optical coupling increases.

  In consideration of the above results, in the present embodiment, the first lens unit 11 having the first curvature radius R1 located on the lower side and the first curvature radius R1 located on the upper side are described. The optical path conversion unit 10 is formed by the second lens unit 12 having a larger second curvature radius R2. With respect to the optical path changing unit 10 formed using the first and second lens units 11 and 12, the relationship between the shift amount of the light receiving element 3 and the optical fiber 14 and the loss of optical coupling was examined. The result is shown by the solid line in FIG.

  In this case, as shown by the solid line in FIG. 10, when the amount of deviation of the optical fiber 14 in the Z-axis direction increases to the minus side, the light emitted from the optical fiber 14 is mainly incident on the first lens unit 11. Therefore, the loss of optical coupling is suppressed by the light collecting action of the first lens unit 11. On the other hand, when the amount of deviation in the Z-axis direction of the optical fiber 14 increases to the plus side, the light emitted from the optical fiber 14 is mainly incident on the second lens unit 12, and therefore air from the second lens unit 12. Leakage light leaking in is reduced, and loss of optical coupling is suppressed. As a result, it can be seen that even when the amount of deviation of the optical fiber 14 in the Z-axis direction increases in either the minus side or the plus side, the loss of optical coupling can be suppressed and the mounting deviation of the optical fiber 14 or the like can be tolerated. As shown in FIG. 10, the first direction is the position of 0 in the extension direction of the central axis of the optical fiber 14, specifically, the shift amount [μm] in the Z-axis direction of the optical fiber shown in FIG. 10. By matching the inner contacts of the outer periphery of the upper surface of the lens unit 11 and the outer periphery of the lower surface of the second lens unit 12, the loss of optical coupling in the first lens unit 11 and the second lens unit 12 can be reduced. A small area can be used efficiently.

  In the receiving module 1, since the optical path conversion unit 10 is provided on the surface of the substrate 2 so as to cover the light receiving element 3, the light receiving element 3 that receives an optical signal perpendicular to the surface of the substrate 2 is used. However, the optical path of the optical signal can be easily converted so that the optical signal parallel to the surface of the substrate 2 is directed in the vertical direction. For this reason, the light receiving element 3 can be mounted horizontally with respect to the substrate 2, and the entire receiving module 1 can be reduced in height.

  Moreover, since the resin layer 6 having the fixing mechanism 7 and the optical path changing unit 10 is formed on the surface of the substrate 2 in a state where the light receiving element 3 is sealed, the bonding strength of the fixing mechanism 7 to the substrate 2 can be increased. . Furthermore, since the fixing mechanism 7 and the optical path changing unit 10 are integrally formed, the assembly process can be simplified, and the manufacturing cost can be reduced. In addition to this, since the fitting groove 8 whose surface is opened is formed in the fixing mechanism 7, the ferrule 13 through which the distal end side of the optical fiber 14 is inserted is inserted from the opening 8 </ b> A and is easily fixed to the fitting groove 8. be able to. Further, since the engaging groove 9 is provided with the engaging portion 9, the engaging portion 9 engages the ferrule 13, so that the distal end side of the optical fiber 14 can be engaged together with the ferrule 13. it can. Thereby, the ferrule 13 and the optical fiber 14 can be easily attached to the fixing mechanism 7.

  The light receiving element 3 is sealed inside the resin layer 6 and the optical fiber 14 is fixed to the fixing mechanism 7 of the resin layer 6. At this time, since the optical signal from the optical fiber 14 can be supplied to the light receiving element 3 through the transparent resin layer 6, it is not necessary to form a gap between the optical fiber 14 and the light receiving element 3. For this reason, foreign matter does not adhere between the optical fiber 14 and the light receiving element 3, and the occurrence of transmission errors can be prevented.

  Next, FIG. 13 and FIG. 14 show a receiving module 31 according to the second embodiment of the present invention. The difference between the receiving module 31 according to the second embodiment and the receiving module 1 according to the first embodiment is that a metal cover is attached to the surface of the resin layer constituting the receiving module. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  The reception module 31 includes a substrate 32, a light receiving element 3, a fixing mechanism 7, a resin layer 33 including the optical path conversion unit 10, and a metal cover 34.

  The substrate 32 has a larger area than the resin layer 33. As a result, a flange portion 32 </ b> A is formed on the outer peripheral edge of the substrate 32 so as to protrude outward from the periphery of the resin layer 33 covering the substrate 32.

  The surface of the resin layer 33 avoids the periphery of the formation region of the fixing mechanism 7 and the optical path conversion unit 10, and the surface of the concave part 33A formed by slightly denting a part of the surface and forming the same horizontal plane without any depression The flat portion 33B, which is the remaining portion, is formed. Further, a protrusion 37 is formed on the surface of the flat portion 33B. The protrusion 37 is a position that sandwiches the fitting groove 8, and the surface of the flat portion 33 </ b> B that is exposed from the flat opening 36 formed in the metal cover 34 when a metal cover 34 described later is put on the resin layer 33. Formed. Other than that, it is formed similarly to the resin layer 6 of the receiving module 1 according to the first embodiment.

  The metal cover 34 includes four L-shaped top plates 34A having rectangular cutouts 34C at the corners of the rectangle and four wall surfaces provided on the periphery of the top plate 34A excluding the cutouts 34C. 34B. Since the wall surface of the notch 34 </ b> C is not suspended, a corner opening 35 is formed at the corner of the metal cover 34. Further, a square planar opening 36 is formed in the top plate portion 34A along the notch 34C. The height of the wall surface 34 </ b> B is formed to be approximately the same as the height of the resin layer 33.

  The metal cover 34 is put on the resin layer 33 in which the adhesive G is applied to the recess 33A. At this time, the protrusion 37 is fitted into the flat opening 36, and the metal cover 34 is positioned on the resin layer 33. Thereafter, when the adhesive G is cured, the top plate portion 34A of the metal cover 34 and the flat portion 33B of the resin layer 33 are fixed in contact with each other. At this time, the ferrule 13 and the optical fiber 14 fitted into the fixing mechanism 7 are drawn out through the corner opening 35.

  Compared with the receiving module 1 of the first embodiment, the receiving module 31 has a metal cover 34 attached to the resin layer 33, so that it is possible to prevent external electromagnetic waves and light from being mixed by the metal cover 34. In addition, noise resistance such as immunity and ESD can be improved, and resistance to static electricity can be increased.

  The substrate 32 is provided with a collar portion 32A. For example, as shown in FIG. 15, in the case of a manufacturing method in which a plurality of receiving modules 31 are integrally formed in a matrix shape on a parent substrate M, then the parent substrate M is cut with a blade B and separated into individual receiving modules 31. A spacer S is provided on the parent substrate M between the adjacent receiving modules 31, and the central portion of the spacer S is cut by the blade B. For this reason, the blade B is not in direct contact with the resin layer 33, and deformation of the resin layer 33 during dicing can be prevented. The flange portion 32A corresponds to the cut spacer S. Therefore, since the deformation of the resin layer 33 in the receiving module 31 is small, the metal cover 34 can be smoothly covered on the resin layer 33.

  Next, FIG. 16 and FIG. 17 show a receiving module 41 according to the third embodiment of the present invention. The difference between the receiving module 41 according to the third embodiment and the receiving module 31 according to the second embodiment is that a light cover is sealed by bonding a metal cover to a resin layer using a low transparent resin film. It is in that. In the present embodiment, the same components as those in the second embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  The reception module 41 includes a substrate 32, a light receiving element 3, a fixing mechanism 7, a resin layer 42 including the optical path conversion unit 10, and a metal cover 44.

  The resin layer 42 differs from the resin layer 33 according to the second embodiment in that the depression 33A is not provided on the surface, and is otherwise formed in the same manner.

  The metal cover 44 includes a top plate portion 44A, a wall surface 44B, and a notch 44C, and is formed so that there is no gap between the top plate portion 44A and the four wall surfaces 44B and between the wall surfaces 44B. Unlike the metal cover 34 according to the second embodiment, the other portions are formed in the same manner.

  A low-transparency resin film 43 is applied to the entire surface of the resin layer 42 excluding the optical path conversion unit 10 and the vicinity thereof. The low transparent resin film 43 is formed using a resin material having a lower optical signal transmittance than the resin layer 42. Specifically, the low-transparency resin film 43 is a filler-containing resin film in which a filler of metal powder or ceramic powder is mixed. As a result, the linear expansion coefficient of the low transparent resin film 43 is set to a value between the linear expansion coefficient of the resin layer 42 and the linear expansion coefficient of the metal cover 44. The metal cover 44 is put on the resin layer 42 to which the low transparent resin film 43 is applied. At this time, the projection 37 and the planar opening 36 are fitted together, and the metal cover 44 is positioned on the resin layer 42. Thereafter, when the low transparent resin film 43 is cured, the metal cover 44 is fixed to the resin layer 42. At this time, the ferrule 13 and the optical fiber 14 fitted to the fixing mechanism 7 are drawn out through the corner opening 45.

  Thus, the receiving module 41 can obtain substantially the same operational effects as those of the first and second embodiments. In particular, in the third embodiment, since the low transparent resin film 43 is provided on the outer surface of the resin layer 42 and the metal cover 44 is bonded to the resin layer 42 using the low transparent resin film 43, the metal cover 44 is provided. Can be used to cover the periphery of the optical path conversion unit 10 in a sealed state. For this reason, the optical path conversion part 10 can be made into the state which does not contact external air, moisture resistance can be improved and reliability can be improved.

  In addition, since the low-transparency resin film 43 is formed of a filler-containing resin film mixed with a filler made of metal or ceramic powder, the difference in linear expansion coefficient between the resin layer 42 and the metal cover 44 can be reduced. The thermal shock resistance can be improved.

  In the third embodiment, the substrate 32 includes the flange portion 32A. However, like the substrate 2 according to the first embodiment, the flange portion may be omitted. Furthermore, in the third embodiment, the low-transparency resin film 43 is formed of a resin film containing a filler. For example, the linear expansion coefficient of the resin material itself is the linear expansion coefficient of the resin layer 42 and the linear expansion coefficient of the metal cover 44. When the difference between the linear expansion coefficients between the resin layer 42 and the metal cover 44 is small, or when the receiving module 41 is used in an environment where the temperature change is small, the resin film without filler is used. May be formed.

  In the second and third embodiments, the metal covers 34 and 44 are attached to the outer surfaces of the resin layers 33 and 42. However, the present invention is not limited to this. For example, a configuration in which the outer surface of the resin layer 6 is covered with a conductive film 52 made of a metal material, a conductive resin material, or the like, as in the receiving module 51 according to the modification shown in FIG. It is good. Even in this case, the conductive film 52 can prevent external electromagnetic waves and the like from being mixed, and noise resistance can be improved.

1, 31, 41, 51 Reception module 2, 32 Substrate 3 Light receiving element 6, 33, 42 Resin layer 7 Fixing mechanism 8 Fitting groove (recess)
DESCRIPTION OF SYMBOLS 9 Locking part 10 Optical path conversion part 10A Inner contact 11 1st lens part 11A 1st reflective surface 12 2nd lens part 12A 2nd reflective surface 13 Ferrule 14 Optical fiber 14A End surface

Claims (2)

A light receiving element, a substrate on which the light receiving element is mounted, and a resin layer covering the surface of the substrate;
The resin layer has an opening on the surface and a fixing mechanism in which a concave portion for mounting the distal end side of the optical fiber inserted from the opening into the ferrule is formed, and the ferrule extends through the first and second reflecting surfaces. An optical path conversion portion formed of an optically transparent resin material that matches the direction and the optical path of the light receiving element;
The optical path changing unit is
A first lens portion having the first reflecting surface formed with a first radius of curvature;
A second lens portion having the second reflecting surface formed with a second radius of curvature larger than the first radius of curvature,
The first lens unit and the first lens unit are arranged such that the outer periphery of the second reflecting surface on the lower surface of the second lens unit and the outer periphery of the first reflecting surface on the upper surface of the first lens unit are inscribed. Two lens parts,
A receiving module in which light emitted from the optical fiber is converted into an optical path by the optical path conversion unit and incident on the light receiving element.   An outer periphery of the upper surface of the first lens unit and an outer periphery of the lower surface of the second lens unit in the extending direction of the central axis of the optical fiber inserted through a ferrule mounted substantially horizontally with respect to the surface of the substrate The receiving module according to claim 1, wherein the optical path conversion unit is formed so that an inner contact is located.

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