Optical transceiver, communication device, and substrate assembly

Abstract

This optical transceiver includes: a plate-form first substrate; a first conversion unit that is provided to a first surface of the first substrate and converts an electric signal to an optical signal; a second conversion unit that is provided to the first surface of the first substrate and converts an optical signal to an electric signal; a cover that covers the first conversion unit and the second conversion unit; and a connection unit that is formed of a resin, incorporates a plurality of connection conductors electrically connected to wiring of the first substrate, and is fixed to a second surface of the first substrate, the optical transceiver being fixed to a second substrate. The first substrate and the connection unit are provided with: a through-hole into which a pin for positioning the first substrate and the connection unit with respect to the second substrate is inserted; and a fixing hole through which passes a fixing tool for pressing the cover, the first substrate, and the connection unit toward the second substrate.

Description

Optical transceiver, communication device, and substrate assembly

[0001] The present invention relates to an optical transceiver, a communication device, and a substrate assembly.

[0002] In a network switch device that realizes co-packaged optics (CPO), a switch ASIC (application specific integrated circuit) and multiple optical transceivers are mounted on a substrate. Patent Document 1 discloses a substrate assembly having multiple optical transceivers mounted thereon, in which the multiple optical transceivers are fixed to the substrate by a fixing mechanism.

[0003] Japanese Patent Application Laid-Open No. 2023-150085

[0004] In a network switch device, mounting optical transceivers at high density is expected to shorten the transmission path of electrical signals between the optical transceivers and the switch ASIC and reduce power consumption. However, the board assembly disclosed in Patent Document 1 requires space for arranging the fixing mechanism, which limits high-density mounting.

[0005] The present invention has been made in view of the above, and has as its object to mount optical transceivers at high density.

[0006] The optical transceiver of the present invention comprises a plate-shaped first substrate, a first conversion unit provided on a first surface of the first substrate for converting an electrical signal into an optical signal, a second conversion unit provided on the first surface of the first substrate for converting an optical signal into an electrical signal, a cover covering the first conversion unit and the second conversion unit, and a connection unit formed of resin, incorporating a plurality of connection conductors electrically connected to the wiring of the first substrate, and fixed to the second surface of the first substrate, wherein the bottom area of ​​the connection unit is less than or equal to the bottom area of ​​the first substrate.

[0007] The optical transceiver may be an optical transceiver fixed to a second substrate, and the first substrate and the connection unit may have through holes into which pins are inserted to position the first substrate and the connection unit relative to the second substrate, and fixing holes through which fixing devices are inserted to press the cover, the first substrate, and the connection unit toward the second substrate.

[0008] In the optical transceiver, the connection unit has a conductor placement area in which the multiple connection conductors are placed and a non-placement area in which the multiple connection conductors are not placed, and the dielectric constant of the conductor placement area may be lower than the dielectric constant of the non-placement area.

[0009] In the optical transceiver, the hardness of a portion of the connection unit on which the force from the fixture acts may be equal to or less than the hardness of a portion on which the force from the fixture does not act.

[0010] In the optical transceiver, the connecting conductor may be an expandable pin, an anisotropic conductive sheet, or a solder ball.

[0011] In the optical transceiver, an area of ​​a conductor arrangement region in which the plurality of connection conductors are arranged may be 80% or less of the bottom area of ​​the connection unit.

[0012] In the optical transceiver, an area of ​​a conductor arrangement region in which the plurality of connection conductors are arranged may be 30% or less of the bottom area of ​​the connection unit.

[0013] In the optical transceiver, the plurality of connection conductors may be arranged at intervals of 0.6 mm or less.

[0014] In the optical transceiver, the fixing device may be a magnet, and the fixing device may be attracted to a magnetic body provided on the bottom side of the connection unit, pushing the cover, the first board, and the connection unit toward the second board.

[0015] The optical transceiver may include a thermally conductive material in contact with the first conversion unit, the second conversion unit, and the cover, which transfers heat generated in the first conversion unit and the second conversion unit to the cover.

[0016] The communication device of the present invention has a plurality of optical transceivers described above, and comprises a first control circuit that transmits communication signals to each of the plurality of optical transceivers via the connecting conductor, and a second substrate on which the first control circuit is mounted.

[0017] In addition, the communication device of the present invention has a plurality of the above-mentioned communication devices, and comprises a third substrate on which the plurality of communication devices are arranged, and a second control circuit mounted on the third substrate and controlling the plurality of communication devices.

[0018] The substrate assembly of the present invention also includes a control circuit that transmits communication signals to each of a plurality of optical transceivers, a substrate on which the control circuit is mounted, a connection unit formed of resin and having a plurality of connection conductors that electrically connect the wiring of the substrate to the wiring of the optical transceivers, the connection unit being fixed to the substrate and provided on each of the optical transceivers, and a pin that penetrates the connection unit and is inserted into the optical transceiver to position the optical transceiver.

[0019] According to the present invention, optical transceivers can be packaged at high density.

[0020] FIG. 1 is a schematic plan view of an optical communication device according to an embodiment. FIG. 2 is a perspective view of a switch device according to an embodiment. FIG. 3 is a schematic plan view of a switch device according to an embodiment. FIG. 4 is an exploded perspective view of a switch device according to an embodiment. FIG. 5 is a perspective view of an optical transceiver according to an embodiment. FIG. 6 is a perspective view of an optical transceiver according to an embodiment. FIG. 7 is an exploded perspective view of an optical transceiver according to an embodiment. FIG. 8 is a diagram illustrating an example of an arrangement of connection conductors. FIG. 9 is a diagram illustrating an example of an arrangement of connection conductors. FIG. 10 is a cross-sectional view taken along line A-A in FIG. 3. FIG. 11 is an enlarged side view of a switch device according to an embodiment. FIG. 12 is a diagram illustrating a modified example of a method for fixing an optical transceiver. FIG. 13 is a diagram illustrating a modified example of a method for fixing an optical transceiver. FIG. 14 is a diagram illustrating a modified example of a method for fixing an optical transceiver. FIG. 15A is a schematic view of a connection unit according to a modified example. FIG. 15B is a schematic view of a connection unit according to a modified example. FIG. 16A is a schematic view of a connection unit according to a modified example. FIG. 16B is a schematic view of a connection unit according to a modified example. 17A and 17B are schematic diagrams of a connection unit according to a modified example;

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below. In addition, in the description of the drawings, the same or corresponding elements are appropriately designated by the same reference numerals. Furthermore, it should be noted that the drawings are schematic, and the dimensional relationships between the elements may differ from the actual ones. There may also be parts in which the dimensional relationships and ratios between the elements differ from one another.

[0022] In addition, an orthogonal coordinate system of X, Y, and Z axes is shown in the figures as appropriate, and directions are explained using this. In the space shown in the orthogonal coordinate system, the direction in which the X component increases is called the +X direction, and the direction in which the X component decreases is called the -X direction. Similarly, the Y and Z components are defined as the +Y direction, -Y direction, +Z direction, and -Z direction. For convenience of explanation, the +Z direction may be referred to as the upward direction and the -Z direction as the downward direction, and the Z axis direction may be referred to as the up-down direction.

[0023] 1 is a schematic plan view of an optical communication device 200 according to an embodiment of the present invention. The optical communication device 200 includes a motherboard 201, an IC 202, and a plurality of switch devices 100. In addition to these components, the optical communication device 200 may also include a power supply module, a cooling fan, and the like (none of which are shown).

[0024] The motherboard 201, which is an example of a third substrate, has a substantially constant thickness in the Z-axis direction and is formed in a rectangular shape when viewed from the +Z direction. The multiple switch devices 100 are mounted on the surface of the motherboard 201 on the +Z direction side, and the IC 202 is mounted on the surface of the motherboard 201 on the -Z direction side. Note that the IC 202 may also be mounted on the surface of the motherboard 201 on the +Z direction side.

[0025] The IC 202, which is an example of a second control circuit, is an integrated circuit that controls the multiple switch devices 100. The IC 202 is electrically connected to the switch devices 100 via a wiring pattern (not shown) formed on the motherboard 201. The IC 202 and the multiple switch devices 100 transmit communication signals to each other via the wiring pattern.

[0026] Fig. 2 is a perspective view of the switch device 100, and Fig. 3 is a schematic plan view of the switch device 100. Fig. 4 is an exploded perspective view of the switch device 100. The switch device 100 includes a daughter board 10, a switch ASIC 20, a plurality of optical transceivers 30, a connection unit 40, and a base 50.

[0027] The base 50 is formed in a frame shape when viewed in the Z-axis direction, and has a rectangular hole 54 in the center that penetrates in the Z-axis direction. The base 50 is preferably formed from a metal with good thermal conductivity. The base 50 is disposed on the −Z direction side of the daughter board 10. The base 50 has positioning pins 51a and 51b on each of its four sides for positioning the connection unit 40 and the optical transceiver 30, and a protrusion 53 on the +Z direction side for dissipating heat from the optical transceiver 30. The base 50 also has a plurality of female-threaded screw holes 52a and 52b on each of its four sides, and a plurality of female-threaded screw holes 55 on each of its corners.

[0028] A plurality of positioning pins 51a are formed at predetermined intervals on the outer edge of the frame along each of the four sides of the base 50. A plurality of screw holes 52a are formed at predetermined intervals on the outer edge of the frame along each of the four sides of the base 50. A plurality of positioning pins 51b are formed at predetermined intervals on the inner edge of the frame along each of the four sides of the base 50. A plurality of screw holes 52b are formed at predetermined intervals on the inner edge of the frame along each of the four sides of the base 50. A plurality of protrusions 53 are formed at predetermined intervals between the screw holes 52a and 52b along each of the four sides of the base 50.

[0029] The daughter board 10, which is a so-called printed wiring board, is plate-shaped and has a square (rectangular) shape when viewed in the Z-axis direction. The daughter board 10 is an example of a second substrate. The daughter board 10 has a through-hole 11a that penetrates in the Z-axis direction and into which a positioning pin 51a is inserted, a through-hole 11b that penetrates in the Z-axis direction and into which a positioning pin 51b is inserted, and a through-hole 13 that penetrates in the Z-axis direction and into which a protrusion 53 is inserted. The daughter board 10 also has through-holes 11a and 11b that penetrate in the Z-axis direction and into which a fastener 37 is inserted, and a through-hole 15 that penetrates in the Z-axis direction and into which a fastener 16, which is a male screw, is inserted. The daughter board 10 also has a plurality of lands formed thereon, which constitute a land grid array 14.

[0030] A switch ASIC 20, which is an example of a first control circuit, is flip-chip mounted on the surface of the daughter board 10 on the +Z direction side in the center thereof. The switch ASIC 20 controls the operation of an optical transceiver 30 fixed on the daughter board 10. The switch ASIC 20 and the optical transceiver 30 are electrically connected via a land grid array 14 formed on the daughter board 10 and a wiring pattern (not shown), and the switch ASIC 20 and the optical transceiver 30 transmit communication signals to each other via the wiring pattern and the land grid array 14. The switch ASIC 20 may be mounted on the daughter board 10 by a method other than flip-chip mounting.

[0031] A plurality of through holes 11a and a plurality of through holes 12a are formed at predetermined intervals on the outer edge side of the daughter board 10 along each of the four sides of the daughter board 10. A plurality of through holes 13 are formed at predetermined intervals on the switch ASIC 20 side of the through holes 11a and 12a along each of the four sides of the daughter board 10. A plurality of land grid arrays 14 are formed at predetermined intervals on the switch ASIC 20 side of the through holes 13 along each of the four sides of the daughter board 10. A plurality of through holes 11b and a plurality of through holes 12b are formed at predetermined intervals on the switch ASIC 20 side of the land grid arrays 14 along each of the four sides of the daughter board 10.

[0032] Through holes 15 are formed at the four corners of daughter board 10. Daughter board 10 is fixed to base 50 by inserting fasteners 16 into through holes 15 and fitting them into screw holes 55. When daughter board 10 is fixed to base 50, positioning pin 51a passes through through hole 11a, positioning pin 51b passes through through hole 11b, and protrusion 53 passes through through hole 13.

[0033] The optical transceivers 30 are arranged on the +Z direction surface of the daughter board 10 along each of the four sides of the daughter board 10. A connection unit 40 is arranged between each optical transceiver 30 and the daughter board 10, and each optical transceiver 30 is fixed to the +Z direction surface of the daughter board 10 by two fasteners 37. Each optical transceiver 30 is connected to an optical fiber cable (not shown) via a connector (not shown).

[0034] The connection unit 40 is located between the optical transceiver 30 and the daughter board 10. The connection unit 40 includes connection conductors (not shown) that electrically connect the optical transceiver 30 and the land grid array 14 of the daughter board 10.

[0035] 5 and 6 are perspective views of the optical transceiver 30, and Fig. 7 is an exploded perspective view of the optical transceiver 30. The optical transceiver 30 includes a substrate 31, a cover 33, a lens assembly 35, positioning pins 36, a fixture 37, and a connection unit 40.

[0036] The cover 33 is made of metal and has a substantially rectangular parallelepiped shape. The cover 33 has a through-hole 33b in its longitudinal center. The through-hole 33b is rectangular when viewed in the Z-axis direction and penetrates the cover 33 in the Z-axis direction. This through-hole 33b accommodates at least a portion of a lens assembly 35 (described later) and a connector 61 (described later). The cover 33 also has two through-holes 33a (described later) that penetrate in the Z-axis direction at corners when viewed from the +Z direction. Male screw fasteners 37 are inserted into the through-holes 33a. The through-holes 33a are an example of fastening holes. The cover 33 is preferably made of a material with high thermal conductivity, such as aluminum, copper, or copper-tungsten.

[0037] The substrate 31, which is an example of a first substrate, is, for example, a printed wiring board, and is formed in a plate shape and rectangular when viewed in the Z-axis direction. The surface of the substrate 31 on the +Z direction side is an example of a first surface, and the surface of the substrate 31 on the -Z direction side is an example of a second surface. The substrate 31 has a through hole 31a through which the positioning pin 51a passes and a through hole 32a through which the fastener 37 passes formed at one end in the longitudinal direction, and a through hole 31b through which the positioning pin 51b passes and a through hole 32b through which the fastener 37 passes formed at the other end in the longitudinal direction. The through holes 32a and 32b are examples of fixing holes.

[0038] Furthermore, a light-emitting element drive circuit 301, a light-emitting element 302, a light-receiving element drive circuit 303, and a light-receiving element 304 are mounted on the surface of the substrate 31 facing in the +Z direction. The light-emitting element 302, which is an example of a first conversion unit, is, for example, a VCSEL array and emits multiple laser beams in the +Z direction. The light-emitting element drive circuit 301 is an electronic circuit that drives the light-emitting element 302 and is connected to the light-emitting element 302. The light-emitting element drive circuit 301 drives the light-emitting element 302 in response to an electrical signal sent from the switch ASIC 20. The light-receiving element 304, which is an example of a second conversion unit, is, for example, a photodiode array and receives multiple laser beams and converts the received light into an electrical signal. The light-receiving element drive circuit 303 is an electronic circuit that drives the light-receiving element 304 and is connected to the light-receiving element 304. The light-receiving element drive circuit 303 outputs the electrical signal sent from the light-receiving element 304 to the switch ASIC 20.

[0039] A lens assembly 35 is attached to the +Z direction side of the light-emitting element 302 and the light-receiving element 304. The lens assembly 35 has a lens array such as a collimating lens array or a condensing lens array. The lens assembly 35 also has positioning pins 36 that position a connector 61 relative to the lens assembly 35. The connector 61 connects an optical fiber cable 62 to the lens assembly 35. The connector 61 has holes through which the positioning pins 36 pass, and is positioned by the positioning pins 36 inserted into these holes. The optical fiber cable 62 is a cable in which multiple optical fibers are arranged in parallel, and is optically connected to the lens assembly 35 by the connector 61.

[0040] The heat dissipation material 34, which is an example of a thermally conductive material, is arranged on the +Z direction surfaces of the light-emitting element drive circuit 301 and the light-receiving element drive circuit 303. The heat dissipation material 34 is made of a heat-conducting sheet (e.g., a graphite sheet) that has relatively high thermal conductivity and is flexible and pliable, or a synthetic material whose main component is silicone. The +Z direction surface of the heat dissipation material 34 contacts the cover 33, and transfers heat generated by the light-emitting element drive circuit 301 and the light-receiving element drive circuit 303 to the cover 33.

[0041] The connection unit 40 is made of an insulating resin material and is rectangular when viewed in the Z-axis direction. The +Z-direction surface of the connection unit 40 is adhered and fixed to the −Z-direction surface of the substrate 31. Note that the area of ​​the surface of the connection unit 40 parallel to the XY plane (bottom area) is equal to or less than the area of ​​the surface of the substrate 31 parallel to the XY plane (bottom area). It is preferable that the connection unit 40 does not protrude beyond the substrate 31 when the optical transceiver 30 with the connection unit 40 adhered to the substrate 31 is viewed from the +Z direction.

[0042] The connection unit 40 has a through hole 43 formed on one end side of the center in the longitudinal direction. The through hole 43 is rectangular when viewed in the Z-axis direction and passes through the connection unit 40 in the Z-axis direction. In addition, the connection unit 40 has a through hole 41a that passes through in the Z-axis direction and a through hole 42a that passes through in the Z-axis direction formed on one end side in the longitudinal direction, and a through hole 41b that passes through in the Z-axis direction and a through hole 42b that passes through in the Z-axis direction formed on the other end side in the longitudinal direction. The through holes 42a and 42b are examples of fixing holes.

[0043] The connection unit 40 also has a plurality of connection conductors 44 located from the center of its length toward the other end. The connection conductors 44 are each conductive, penetrate the connection unit 40 in the Z direction, and electrically connect the wiring pattern formed on the surface of the substrate 31 on the -Z direction side to the lands of the land grid array 14. The connection conductors 44 can be configured, for example, as contact terminals having elastically expandable pins extending in the Z-axis direction. Note that the connection conductors 44 are not limited to expandable pins, and may also be anisotropic conductive sheets, solder balls, or conductive adhesive.

[0044] FIG. 8 is a diagram showing an example of the arrangement of the connection conductors 44. The distance between adjacent connection conductors 44 in the X-axis direction is, for example, 0.3 mm or 0.6 m. The connection conductors 44 include connection conductors 44a and connection conductors 44b. The connection conductors 44a are electrically connected to a wiring pattern that transmits communication signals on the substrate 31 and to a land in the land grid array 14 that is connected to the wiring pattern that transmits communication signals. The connection conductors 44b are electrically connected to a ground wiring pattern on the substrate 31 and to a land in the land grid array 14 that is connected to the ground wiring pattern. The connection conductors 44 are arranged in a triangular lattice pattern, and in each row of multiple rows of connection conductors 44 in the X-axis direction, a set of two connection conductors 44a and a set of three connection conductors 44b are arranged alternately.

[0045] The arrangement of the multiple connection conductors 44 is not limited to a triangular lattice arrangement, and other arrangements are also possible. Fig. 9 is a diagram showing another example of the arrangement of the connection conductors 44. In the example shown in Fig. 9, the multiple connection conductors 44 are arranged in a square lattice pattern. The multiple rows of connection conductors 44 in the X-axis direction are arranged such that rows in which only the connection conductors 44b are lined up and rows in which the connection conductors 44a and the connection conductors 44b are lined up alternately. Furthermore, in the example shown in Fig. 9, in a row in which the connection conductors 44a and the connection conductors 44b are lined up in the Y-axis direction, pairs of two connection conductors 44a and one connection conductor 44b are lined up alternately.

[0046] When fixing the connection unit 40 and the optical transceiver 30 to the daughter board 10, the positioning pin 51a passes through the through hole 41a and is inserted into the through hole 31a, the positioning pin 51b passes through the through hole 41b and is inserted into the through hole 31b, and the protrusion 53 is inserted into the through hole 43. This positions the connection unit 40 and the substrate 31 relative to the daughter board 10. When fixing the connection unit 40 and the optical transceiver 30 to the daughter board 10, the fastener 37 passes through the through hole 33a, the through holes 32a and 32b, the through holes 42a and 42b, and the through holes 12a and 12b, and is fitted into the screw holes 52a and 52b. When the fastener 37 passes through the optical transceiver 30, the connection unit 40, and the daughter board 10 and is fitted into the screw hole 52a, the optical transceiver 30 and the connection unit 40 are pressed toward the daughter board 10 and fixed. The connection unit 40 and the substrate 31 are positioned by the positioning pins 51a and 51b, allowing the optical transceiver 30 to be fixed accurately onto the daughter board 10. When fixing the optical transceiver 30 onto the daughter board 10, the connection unit 40 may not be glued to the surface of the substrate 31 on the -Z direction side, but the optical transceiver 30 and the connection unit 40 may be stacked and fixed with the fixture 37.

[0047] 10 is a cross-sectional view taken along line A-A in FIG. 3 , and FIG. 11 is an enlarged side view of the switch device 100. As shown in FIGS. 10 and 11 , when the optical transceiver 30 and the connection unit 40 are fixed on the daughter board 10 by the fasteners 37, the connection conductors 44 come into contact with the lands of the land grid array 14, electrically connecting the wiring pattern on the substrate 31 to the wiring pattern on the daughter board 10, enabling the switch ASIC 20 to transmit communication signals with the light-emitting element drive circuit 301 and the light-receiving element drive circuit 303. Furthermore, when the optical transceiver 30 and the connection unit 40 are fixed on the daughter board 10 by the fasteners 37, the convex portions 53 come into contact with the substrate 31, as shown in FIG. 10 , and heat generated by the optical transceiver 30 is transferred to the convex portions 53, thereby dissipating the heat from the optical transceiver 30. Furthermore, since the connection unit 40 fixed to the daughter board 10 does not protrude beyond the substrate 31 when viewed from the +Z direction, the distance between adjacent optical transceivers 30 can be shortened when arranging multiple optical transceivers 30 in parallel, allowing for high-density mounting of the optical transceivers 30. Note that in this embodiment, the base 50 may not be configured to include the protrusion 53.

[0048] [Modifications] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be implemented in various other forms. For example, the above-described embodiments may be modified as follows to implement the present invention. The above-described embodiments and the following modifications may be combined with each other. The present invention also includes configurations in which the components of the above-described embodiments and modifications are appropriately combined. Furthermore, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-described embodiments and modifications, and various modifications are possible.

[0049] In the above-described embodiment, the optical transceiver 30 is fixed to the daughter board 10 by fitting the fastener 37, which is a male screw, into the screw holes 52a and 52b. However, the fastener for fixing the optical transceiver 30 to the daughter board 10 is not limited to a male screw and may be, for example, a magnet. FIG. 12 is an enlarged side view of the switch device 100, illustrating a modified example in which the optical transceiver 30 is fixed to the daughter board 10 using the fastener 37a, which is a magnet. In this modified example, the base 50 has a through-hole 52c formed at the position of the screw hole 52a, which passes through the base 50 in the Z-axis direction, and a through-hole 52d formed at the position of the screw hole 52b, which passes through the base 50 in the Z-axis direction. Cylindrical magnetic pins 56 are fitted into the through-holes 52c and 52d to secure the optical transceiver 30 to the daughter board 10. Fixing device 37a is a magnet that passes through through-hole 33a, through-holes 32a and 32b, through-holes 42a and 42b, and through-holes 12a and 12b, and is attracted to pin 56 by magnetic force, thereby pressing and fixing cover 33, substrate 31, and connection unit 40 toward daughter board 10. In this modification, connection unit 40 and substrate 31 are positioned by positioning pins 51a and 51b, so that optical transceiver 30 can be fixed onto daughter board 10 with high precision.

[0050] In the above-described embodiment, the optical transceiver 30 is fixed on the daughter board 10 by fitting the fixing device 37, which is a male screw, into the screw holes 52a and 52b. However, the fixing device 37 that fixes the optical transceiver 30 on the daughter board 10 may be passed through to the motherboard 201. FIG. 13 is an enlarged side view of the optical communication device 200, showing a modified example in which the fixing device 37 passes through to the motherboard 201 to fix the optical transceiver 30 on the daughter board 10. In this modified example, the motherboard 201 has through-holes 201a and 201b through which the fixing device 37 passes. Furthermore, on the −Z direction side of the motherboard 201 is a housing 203 of the optical communication device 200, which has a plurality of female-threaded screw holes 203a and 203b formed in the housing 203 into which the fixing device 37 fits. In this modification, the fastener 37 passes through the through-hole 33a, the through-holes 32a and 32b, the through-holes 42a and 42b, the through-holes 12a and 12b, and the through-holes 201a and 201b, and is fitted into the screw hole 203a. In this modification, the connection unit 40 and the substrate 31 are positioned by the positioning pins 51a and 51b, so that the optical transceiver 30 can be fixed onto the daughter board 10 with high precision.

[0051] FIG. 14 is an enlarged side view of the optical communication device 200, illustrating a modified method for fixing the optical transceiver 30. In the present invention, the connection unit 40 may be pre-adhered and fixed onto the daughter board 10, as shown in FIG. 14 . The combination of the base 50 and the daughter board 10 to which the connection unit 40 has been pre-fixed is an example of a board assembly. In this modified example, the positioning pins 51 a and 51 b that pass through the daughter board 10 and the connection unit 40 are exposed on the +Z direction side of the connection unit 40. The optical transceiver 30 is positioned by fitting the positioning pin 51 a into the through hole 31 a and the positioning pin 51 b into the through hole 31 b. With the optical transceiver 30 positioned in this manner, the fixture 37 is passed through the through-holes 33a, 32a and 32b, 42a and 42b, 12a and 12b, and 201a and 201b and fitted into the screw hole 203a, thereby fixing the optical transceiver 30 to the daughter board 10. In this modification, the connection unit 40 and the substrate 31 are positioned by the positioning pins 51a and 51b, so that the optical transceiver 30 can be fixed to the daughter board 10 with high precision.

[0052] 15A is a view of a connection unit 40a according to a modification from the -Z direction, and FIG. 15B is a side view of the connection unit 40a. The connection unit 40a has a smaller area than the connection unit 40 according to the embodiment, and differs from the connection unit 40 in that it does not include the through-holes 41a, 42a, and 43. The connection unit 40a and the substrate 31 are positioned by the positioning pin 51a, allowing the optical transceiver 30 to be fixed onto the daughter board 10 with high precision.

[0053] A metal connection unit 40b may be disposed on the +X side of the connection unit 40a. Fig. 16A shows a connection unit 40b according to a modified example, viewed from the -Z side, and Fig. 16B shows a side view of the optical transceiver 30 and the connection units 40a and 40b. The connection unit 40b is bonded to the connection unit 40a and includes a through-hole 41c through which a positioning pin 51a passes, a through-hole 42c through which a fastener 37 passes, and a through-hole 43b through which a protrusion 53 passes. The connection unit 40b and the substrate 31 are positioned by the positioning pin 51a, allowing the optical transceiver 30 to be fixed to the daughter board 10 with high precision.

[0054] In the present invention, the connection unit 40 may have a region where the connection conductors 44 are arranged made of a resin material with a low dielectric constant. FIG. 17A is a view of a connection unit 40c according to a modified example, viewed from the -Z direction, and FIG. 17B is a side view of the optical transceiver 30 and the connection unit 40c. The connection unit 40c includes a conductor arrangement region 45 where multiple connection conductors 44 are arranged, and the dielectric constant of the material of the conductor arrangement region 45 is equal to or lower than the dielectric constant of the material of the surrounding non-arrangement region. The area of ​​the conductor arrangement region 45 is preferably 80% or less, and more preferably 30% or less, of the area of ​​the connection unit 40c. With the connection unit 40c, the dielectric constant around the connection conductors 44 is low, allowing the connection conductors 44 to easily transmit high-frequency signals.

[0055] In the present invention, the area of ​​the connection unit 40 is not limited to being less than the area of ​​the substrate 31, but may be greater than the area of ​​the substrate 31 as long as the optical transceiver 30 can be mounted at a high density, and the connection unit 40 may protrude beyond the substrate 31 when viewed from the +Z direction.

[0056] In the present invention, the hardness of the material around the through holes 42a, 42b, where a large force from the fixing device 37 acts, may be less than the hardness of the other parts, i.e., may be the same hardness as the other parts or softer than the other parts.

[0057] The present invention can be used in optical transceivers, communication devices, and substrate assemblies.

[0058] REFERENCE SIGNS LIST 10 daughter board 20 switch ASIC 30 optical transceiver 31 substrate 33 cover 37 fixture 40 connection unit 44 connection conductor 50 base 100 switch device 200 optical communication device 201 motherboard 202 IC

Claims

1. An optical transceiver comprising: a plate-shaped first substrate; a first conversion unit provided on a first surface of said first substrate for converting electrical signals into optical signals; a second conversion unit provided on the first surface of said first substrate for converting optical signals into electrical signals; a cover that covers said first conversion unit and said second conversion unit; and a connection unit made of resin, incorporating a plurality of connection conductors that electrically connect to the wiring of said first substrate, and fixed to the second surface of said first substrate, wherein the bottom surface area of ​​said connection unit is equal to or smaller than the bottom surface area of ​​said first substrate.

2. An optical transceiver as described in claim 1, which is fixed to a second board, wherein the first board and the connection unit have through holes into which pins are inserted to position the first board and the connection unit relative to the second board, and fixing holes through which fixing devices are passed that press the cover, the first board, and the connection unit toward the second board.

3. An optical transceiver as described in claim 1, wherein the connection unit has a conductor placement area in which the plurality of connection conductors are placed and a non-placement area in which the plurality of connection conductors are not placed, and the dielectric constant of the conductor placement area is equal to or lower than the dielectric constant of the non-placement area.

4. The optical transceiver according to claim 2, wherein the hardness of the portion of the connection unit to which the force from the fixing tool acts is equal to or less than the hardness of the portion to which the force from the fixing tool does not act.

5. The optical transceiver according to claim 1, wherein the connecting conductor is an expandable pin, an anisotropic conductive sheet, or a solder ball.

6. The optical transceiver according to claim 1, wherein the area of ​​the conductor arrangement region in which the plurality of connection conductors are arranged is 80% or less of the bottom area of ​​the connection unit.

7. The optical transceiver according to claim 1, wherein the area of ​​the conductor arrangement region in which the plurality of connection conductors are arranged is 30% or less of the bottom area of ​​the connection unit.

8. The optical transceiver according to claim 1, wherein the plurality of connection conductors are arranged at intervals of 0.6 mm or less.

9. The optical transceiver according to claim 2, wherein the fixing device is a magnet, and the fixing device is attracted to a magnetic body provided on the bottom side of the connection unit, thereby pushing the cover, the first board, and the connection unit toward the second board.

10. An optical transceiver as described in claim 1, further comprising a thermally conductive material in contact with the first conversion unit, the second conversion unit, and the cover, which transfers heat generated in the first conversion unit and the second conversion unit to the cover.

11. A communications device comprising a plurality of optical transceivers according to any one of claims 1 to 10, a first control circuit that transmits a communication signal to each of the plurality of optical transceivers via the connecting conductor, and a second substrate on which the first control circuit is mounted.

12. A communication device comprising a plurality of communication devices according to claim 11, a third board on which the plurality of communication devices are arranged, and a second control circuit mounted on the third board and controlling the plurality of communication devices.

13. A board assembly comprising: a control circuit that transmits communication signals to each of a plurality of optical transceivers; a board on which the control circuit is mounted; a connection unit formed of resin and having a plurality of connection conductors that electrically connect the wiring of the board to the wiring of the optical transceivers, the connection unit being fixed to the board and provided on each of the optical transceivers; and a pin that penetrates the connection unit and is inserted into the optical transceiver to position the optical transceiver.

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