JP7474143B2 - Optical Modules - Google Patents

Description

The present invention relates to an optical module.

TO-CAN (Transistor Outline Can) type packages transmit electrical signals to optical semiconductor elements using leads that are held in the through holes of the eyelets via a dielectric such as glass (Patent Documents 1 and 2). The leads are joined to the wiring pattern of the ceramic substrate by soldering.

JP 2017-50357 A JP 2011-123188 A

Soldering allows for reduced inductance because no wire is used, but it requires expensive pellets (e.g., AuSn solder). Soldering also requires the leads to be positioned precisely, which is difficult to control.

The present invention aims to provide electrical connections using wires that do not increase inductance.

(1) The optical module according to the present invention comprises a conductive block having a first surface and a second surface and a plurality of through holes penetrating between the first surface and the second surface, a plurality of leads including signal leads, each of which is fixed inside the plurality of through holes while being insulated from the conductive block, a relay board having two or more layers in a structure in which a plurality of conductor layers are arranged with an insulating layer interposed therebetween, a photoelectric element for converting at least one of an optical signal and an electrical signal to the other, and a plurality of wires including a signal wire, the relay board having a first end face fixed opposite to the first surface of the conductive block, a second end face opposite to the first end face, and a first end face and a front end face fixed to the first end face and a front end face fixed to the front end face and a signal wire. The relay board has a front surface and a back surface that define the thickness of the relay board between the second end surface, the front surface has an inclined surface that inclines so that the thickness decreases from the first end surface in the direction of the second end surface, at least at a position closer to the first end surface than the second end surface, the multiple conductor layers have a signal pattern located on the front surface such that a portion of the signal pattern is located on the inclined surface, and a first ground pattern located so that the signal pattern extends from the back surface to the first end surface and the second end surface, and the signal wire has one end bonded to the signal lead and the other end bonded to the signal pattern at the inclined surface.

The present invention uses signal wires, which reduces costs. In addition, the signal wires are bonded to an inclined surface, which simplifies the bonding process and allows for the use of short signal wires, thereby reducing inductance.

(2) The optical module described in (1) may be characterized in that the plurality of conductor layers include a second ground pattern located on an inner layer of the relay substrate and electrically connected to the first ground pattern.

(3) The optical module according to (1) or (2), wherein the plurality of wires include a ground wire, and the ground wire has one end bonded to the first ground pattern at the second end surface.

(4) The optical module described in (3) may be characterized in that the conductive block has a base portion that protrudes from the first surface, and the other end of the ground wire is bonded to the base portion.

(5) The optical module according to any one of (1) to (4) may further include a conductive adhesive interposed between the first surface and the first end surface, electrically connecting the first ground pattern to the conductive block and fixing the relay substrate to the conductive block.

(6) The optical module according to any one of (1) to (5) may be characterized in that the relay substrate is supported by the conductive block only at the first end surface.

(7) The optical module according to any one of (1) to (6) may be characterized in that at least a portion of the relay substrate does not overlap any of the plurality of through holes.

(8) The optical module according to any one of (1) to (7) may be characterized in that the signal wire is bonded to the tip surface of the signal lead.

(9) The optical module described in (8) may be characterized in that the signal lead has a holding portion located inside one of the corresponding through holes, and the tip surface is larger than the diameter of the holding portion.

(10) The optical module according to any one of (1) to (9), wherein the plurality of wires further includes a wire bonded to the signal pattern on the surface.

(11) The optical module according to any one of (1) to (10), wherein the signal pattern includes a signal line and a pad portion located on the inclined surface and larger than the wiring width of the signal line.

(12) The optical module according to any one of (1) to (11), wherein the first ground pattern is positioned so as to extend from the back surface to the second end surface.

(13) The optical module described in (12) may be characterized in that the first ground pattern extends beyond the second end face to the surface.

(14) The optical module described in (13) may be characterized in that the plurality of wires further includes a wire bonded to the first ground pattern on the surface.

(15) The optical module according to any one of (1) to (10) may be characterized in that the first relay board and the second relay board are each the relay board, and a differential transmission line is formed by the signal pattern of the first relay board and the signal pattern of the second relay board.

(16) The optical module according to the present invention comprises a conductive block having a first surface and a second surface and having a plurality of through holes penetrating between the first surface and the second surface, a plurality of leads including signal leads, each of which is fixed inside the plurality of through holes while being insulated from the conductive block, a relay board having two or more layers in a structure in which a plurality of conductor layers are arranged with an insulating layer interposed therebetween, a photoelectric element for converting at least one of an optical signal and an electrical signal to the other, and a plurality of wires including a signal wire, wherein the relay board has a first end face fixed opposite to the first surface of the conductive block, a second end face opposite to the first end face, and The relay board has a front surface and a back surface that define the thickness of the relay board between the first end surface and the second end surface, the front surface has an inclined surface that inclines so that the thickness decreases from the first end surface in the direction of the second end surface, the multiple conductor layers have a signal pattern located on the inclined surface, a first ground pattern located on the back surface, and a first conductor that is embedded in the relay board and connects to the first ground pattern so as to have a first exposed surface exposed on the first end surface, and the signal wire has one end bonded to the signal lead and the other end bonded to the signal pattern on the inclined surface.

(17) The optical module described in (16) may be characterized in that the plurality of conductor layers further include a second conductor that is embedded in the relay substrate and connected to the first ground pattern so as to have a second exposed surface that is exposed to the second end surface.

(18) The optical module described in (17) may further include a conductive piece that is in surface contact with the second exposed surface of the second conductor and has at least a surface made of a conductive material, and the plurality of wires may include a ground wire having one end bonded to the surface of the conductive piece.

(19) The optical module described in (18) may be characterized in that the conductive piece is entirely made of the conductive material.

(20) The optical module described in (18) may be characterized in that the conductive piece includes a main body made of an insulating material and a metal film formed on the main body, a part of the metal film being a connection part with the second exposed surface, and another part of the metal film not facing the second end surface being a bonding part of the ground wire.

(21) The optical module according to any one of (18) to (20) may further include a mounting substrate on which the photoelectric element is mounted, and a support block that supports the mounting substrate, is made of a conductive material, and has the other end of the ground wire bonded thereto.

1 is a perspective view of an optical module according to a first embodiment; FIG. 2 is a perspective view showing a conductive block and an electronic component mounted thereon. FIG. FIG. FIG. 1 is a diagram for explaining wire bonding. FIG. 11 is a perspective view showing a part of an optical module according to a second embodiment. FIG. 11 is a perspective view showing a part of an optical module according to a third embodiment. FIG. 13 is a perspective view showing a part of an optical module according to a fourth embodiment. FIG. 13 is a perspective view showing a part of an optical module according to a fifth embodiment. FIG. 13 is a cross-sectional view showing a part of an optical module according to a fifth embodiment. FIG. 13 is a perspective view showing a relay substrate of an optical module according to a fifth embodiment. FIG. 13 is a perspective view showing a part of an optical module according to a sixth embodiment. FIG. 13 is a cross-sectional view showing a part of an optical module according to a sixth embodiment.

The following describes an embodiment of the present invention in detail with reference to the drawings. Components with the same reference numerals in all the drawings have the same or equivalent functions, and their repeated explanation will be omitted. Note that the size of the figures does not necessarily correspond to the magnification.

[First embodiment]
1 is a perspective view of an optical module according to a first embodiment. The optical module 100 is a TO-CAN (Transistor Outline-Can) type optical module, and may be any of a transmitter optical sub-assembly (TOSA: Transmitter Optical Sub-Assembly) having a light-emitting element, a receiver optical sub-assembly (ROSA: Receiver Optical Sub-Assembly) having a light-receiving element, and a bidirectional module (BOSA: Bidirectional Optical Sub-Assembly) having both a light-emitting element and a light-receiving element. The optical module 100 has a flexible printed circuit board (FPC) 102 and is adapted to be connected to a printed circuit board (PCB) 104. The optical module 100 has a conductive block 10 (e.g., an eyelet).

2 is a perspective view showing the conductive block 10 and electronic components mounted thereon. The conductive block 10 is made of a conductive material such as metal, and has a first surface 12 and a second surface 14.
The conductive block 10 has a plurality of through holes 16 that extend between the first surface 12 and the second surface 14. The conductive block 10 has a base portion 18 that is integral with the first surface 12. The base portion 18 is raised above the first surface 12. The base portion 18 is also made of a conductive material. The conductive block 10 is connected to a reference potential (e.g., ground).

The optical module 100 has a plurality of leads L. The plurality of leads L are fixed inside a plurality of through holes 16, insulated from the conductive block 10. For example, the through holes 16 are filled with an insulating material 20 such as glass. The plurality of leads L protrude from the first surface 12. The plurality of leads L also protrude from the second surface 14, and are connected to the flexible substrate 102 (FIG. 1).

The multiple leads L include a signal lead 22. The signal lead 22 has a retaining portion 24 located inside a corresponding one of the multiple through holes 16. The signal lead 22 is located inside the through hole 16 of the conductive block 10 at the reference potential and forms a coaxial line. The tip surface of the signal lead 22 is larger in diameter than the retaining portion 24.

The optical module 100 has a photoelectric element 26 for converting at least one of an optical signal and an electrical signal into the other. The photoelectric element 26 is driven in a single-ended manner. The photoelectric element 26 is mounted on a mounting board 28. The mounting board 28 is mounted on a pedestal 18. A bypass capacitor 30 is mounted on the pedestal 18. The back surface (electrode) of the bypass capacitor 30 is conductive to the pedestal 18 and connected to a reference potential (e.g., ground).

The mounting substrate 28 has a mounting surface on which the photoelectric element 26 is mounted. The photoelectric element 26 is arranged so that the optical axis OX is oriented in a direction parallel to the mounting surface. The mounting substrate 28 has a wiring pattern 32 on the mounting surface.

Figure 3 is a plan view of the wiring pattern 32. The wiring pattern 32 is electrically connected to the photoelectric element 26. More specifically, the wiring pattern 32 has a ground electrode 34 to which the back surface (electrode) of the photoelectric element 26 is joined. The ground electrode 34 is integrated with the side electrode 36 and is electrically connected to the base portion 18 on the side opposite the mounting surface. The wiring pattern 32 has a signal electrode 38 for inputting a high-frequency signal to the photoelectric element 26.

2, the optical module 100 has a relay substrate 40. The relay substrate 40 has a front surface 42 and a back surface 44 that define the thickness. A first end surface 46 and a second end surface 48 are connected to both ends of the front surface 42 (or the back surface 44). The second end surface 48 is the surface opposite to the first end surface 46. The front surface 42 has an inclined surface 50 at a position closer to the first end surface 46 than the second end surface 48. The inclined surface 50 is inclined so that the thickness decreases from the first end surface 46 to the second end surface 48. The first end surface 46 is fixed opposite to the first surface 12 of the conductive block 10. For fixing, it is preferable that the first end surface 46 is large to some extent, and there is a limit to how thin the relay substrate 40 can be made.

Figure 4 is a detailed view of the relay board 40. A conductive adhesive 52 is interposed between the first surface 12 and the first end surface 46. The relay board 40 is fixed to the conductive block 10 by the conductive adhesive 52. The relay board 40 may be supported on the conductive block 10 only by the first end surface 46. At least a portion of the relay board 40 (first end surface 46) does not overlap any of the multiple through holes 16 (insulating material 20) as shown in Figure 2, so that the adhesive force of the conductive adhesive 52 is ensured. The relay board 40 has a structure in which multiple conductor layers 54 (e.g., metal) are arranged with insulating layers 56 (e.g., ceramic) interposed therebetween.

(Signal pattern)
The plurality of conductor layers 54 have a signal pattern 58. The signal pattern 58 is located on the front surface 42. A portion of the signal pattern 58 is disposed on the inclined surface 50. The signal pattern 58 includes a signal line 60. The signal pattern 58 includes a pad portion 62 that is larger than the wiring width of the signal line 60. The pad portion 62 is located on the inclined surface 50.

(First ground pattern)
The plurality of conductor layers 54 have a first ground pattern 64. The first ground pattern 64 is located so as to extend from the rear surface 44 to each of the first end surface 46 and the second end surface 48. The first ground pattern 64 is electrically connected to the conductive block 10 at the first end surface 46 by the conductive adhesive 52. The first ground pattern 64 extends beyond the second end surface 48 to reach the front surface 42.

(Second ground pattern)
The plurality of conductor layers 54 has a second ground pattern 66. The second ground pattern 66 is located on an inner layer of the relay board 40 and is electrically connected to the first ground pattern 64. The plurality of conductor layers 54 includes a first via 68. The first via 68 penetrates the insulating layer 56 to connect the first ground pattern 64 and the second ground pattern 66.

The second ground pattern 66 is closer to the signal pattern 58 than the first ground pattern 64. This makes it possible to increase the capacitance (prevent a decrease). Note that on the inclined surface 50, the signal pattern 58 is farther away from the second ground pattern 66, but the pad portion 62 is larger than the signal line 60, which also prevents a decrease in capacitance. The second ground pattern 66 is on one side of the insulating layer 56 (dielectric), and the signal pattern 58 is on the other side of the dielectric, forming a microstrip line.

(Third Grand Pattern)
The plurality of conductor layers 54 includes a third ground pattern 70. The third ground pattern 70 is located on the front surface 42 and electrically connects to the second ground pattern 66. The plurality of conductor layers 54 includes a second via 72. The second via 72 passes through the insulating layer 56 and connects the second ground pattern 66 and the third ground pattern 70.

(Wire)
2, the optical module 100 has a plurality of wires. According to this embodiment, the cost can be reduced because wires are used instead of expensive pellets.

One end of the signal wire 74 is bonded to the signal lead 22. The signal wire 74 is bonded to the tip surface of the signal lead 22. The tip surface of the signal lead 22 has a larger diameter than the holding portion 24 to ensure a bonding area. The other end of the signal wire 74 is bonded to the signal pattern 58 at the inclined surface 50. The signal lead 22 and the signal pattern 58 are electrically connected by the signal wire 74. Note that even if the inductance increases due to the use of the signal wire 74, the impedance can be balanced by increasing the capacitance at the inclined surface 50.

One end of wire W1 is bonded to signal pattern 58 on surface 42 of relay substrate 40. The other end of wire W1 is bonded to signal electrode 38 (see FIG. 3). Signal electrode 38 and photoelectric element 26 are connected via wire W7.

One end of the ground wire 76 is bonded to the first ground pattern 64 at the second end surface 48. The other end of the ground wire 76 is bonded to the base 18. One end of a wire W2 is bonded to the first ground pattern 64 at the front surface 42 of the relay board 40. The other end of the wire W2 is bonded to the ground electrode 34 (see FIG. 3) of the mounting board 28. One end of a wire W3 is bonded to the first ground pattern 64 at the back surface 44 of the relay board 40. The other end of the wire W3 is bonded to the base 18.

One end of a wire W4 is bonded to the third ground pattern 70 (see FIG. 4) on the surface 42 of the relay board 40. The other end of the wire W4 is bonded to the base 18. The upper electrode of the bypass capacitor 30 is connected to the lead L via a wire W5 so that a voltage can be applied. The voltage is also connected to the photoelectric element 26 via another wire W6 to supply the power supply voltage. The photoelectric element 26 is also connected to the signal electrode 38 (see FIG. 3) by a wire W7.

(Production method)
5 is a diagram for explaining wire bonding. The manufacturing method of the optical module 100 includes wire bonding. One end of the signal wire 74 is bonded to the tip surface of the signal lead 22 using a capillary 78.

Then, the other end of the signal wire 74 is bonded to the signal pattern 58 on the inclined surface 50. This bonding is performed by tilting the conductive block 10 so that the inclined surface 50 is perpendicular to the capillary 78. Bonding to the inclined surface 50 can avoid interference with other components, allowing for stable production regardless of component variations.

In this embodiment, the signal wire 74 is bonded to the inclined surface 50, which makes the bonding process easier and allows the use of a short signal wire 74, thereby reducing inductance. This makes it possible to improve the characteristics.

Second Embodiment
6 is a perspective view showing a part of an optical module according to a second embodiment. The optical module has a thermoelectric cooler 280. The thermoelectric cooler 280 has an upper surface and a lower surface. The upper surface and the lower surface are made of an insulator such as ceramic. The lower surface is fixed to the first surface 212 of the conductive block 210. A thermally conductive adhesive may be used for fixing. The thermoelectric cooler 280 has a Peltier element (not shown) therein for transferring heat between the upper surface and the lower surface.
For example, the upper surface serves as a heat absorbing surface and the lower surface serves as a heat releasing surface, but the reverse can be reversed. The electrodes of the thermoelectric cooler 280 are connected to leads L by wires W.

A metal layer 282 is laminated on the upper surface of the thermoelectric cooler 280. The metal layer 282 serves as a reference potential plane (e.g., a ground plane). A support block 284 is interposed between the metal layer 282 and the mounting substrate 28 (see FIG. 3). The support block 284 is made of metal, which is a conductive material. The support block 284 is electrically connected to the metal layer 282 and is electrically connected to the ground electrode 34 via the side electrode 36 of the mounting substrate 28.

One end of the ground wire 76 is bonded to the first ground pattern 64 at the second end surface 48. The other end of the ground wire 76 is bonded to the support block 284. One end of a wire W is bonded to the third ground pattern 70 on the surface 42 of the relay board 40. The other end of the wire W is bonded to the support block 284.

The bypass capacitor 30 is mounted on the support block 284. The back surface (electrode) of the bypass capacitor 30 is conductive to the support block 284 and connected to a reference potential (e.g., ground). The other electrode of the bypass capacitor 30 is connected to a lead L via a wire W so that a voltage can be applied. The voltage is also connected to the photoelectric element 26 via another wire W to supply the power supply voltage. The contents described in the first embodiment are applicable to this embodiment.

[Third embodiment]
7 is a perspective view showing a part of the optical module according to the third embodiment. A differential transmission line is formed by a signal pattern 358 of the first relay board 340A and a signal pattern 358 of the second relay board 340B. The signal pattern 358 may have a symmetrical shape with respect to the signal transmission direction. If the first relay board 340A and the second relay board 340B have the same structure, it is possible to reduce costs by sharing parts.

As a photoelectric element 326 capable of differential driving, a directly modulated laser (DML) is assumed. Since DMLs generally need to be driven with a high current, their characteristic impedance is often set low to reduce power consumption. The characteristic impedance of high-frequency lines is generally set to 25 Ω. To match the characteristic impedance to 25 Ω, the line width of the signal pattern 358 is relatively large (approximately 0.5 to 0.7 mm). In the first embodiment, a single-phase method with 50 Ω matching is assumed.

The first relay board 340A and the second relay board 340B do not overlap any of the through holes 316 overall. The insulating material 320 inside the through holes 316 has a weak adhesive force with the conductive adhesive 352, but since the conductive adhesive 352 does not adhere to the insulating material 320, the adhesive force between the first relay board 340A and the second relay board 340B and the conductive block 310 is strong.

The wiring pattern 332 of the mounting substrate 328 includes a pair of differential signal wiring 386. A back electrode (not shown) of the photoelectric element 326 is electrically connected to one of the pair of differential signal wiring 386. The other of the pair of differential signal wiring 386 and the photoelectric element 326 are connected by a wire W.

Each of the pair of signal patterns 358 is connected to a corresponding one of the pair of differential signal wirings 386 by a wire W. Each of the pair of signal patterns 358 is also connected to a corresponding signal lead 322 by a wire W. In this way, the pair of signal leads 322 are electrically connected to the photoelectric element 326. The contents described in the first embodiment are applicable to this embodiment.

[Fourth embodiment]
8 is a perspective view showing a part of an optical module according to a fourth embodiment. In this embodiment, a signal pattern 458 is present on the entire inclined surface 450 on the surface 442 of the relay board 440. The entire surface 442 may be the inclined surface 450. This allows the thickness of the relay board 440 to be thin, so that the impedance can be brought close to a desired value even without an inner-layer ground pattern, resulting in a configuration with excellent cost resistance. The contents described in the third embodiment are applicable to this embodiment.

[Fifth embodiment]
Fig. 9 is a perspective view showing a part of an optical module according to a fifth embodiment. Fig. 10 is a cross-sectional view showing a part of an optical module according to a fifth embodiment. In this embodiment, a single-ended method is adopted for transmitting digital data. The optical module has two or more layers of relay substrates 540.

Figure 11 is a perspective view showing a relay substrate 540 of an optical module according to the fifth embodiment. The relay substrate 540 has a structure in which multiple conductor layers are arranged with insulating layers interposed between them. This embodiment differs from the second embodiment (Figure 6) in the relay substrate 540.

The relay board 540 has a first conductor 580 (e.g., a buried via). The first conductor 580 is embedded in the relay board 540 (insulating layer) and connected to the first ground pattern 564. The first conductor 580 has a first exposed surface 582 exposed at the first end surface 546. The first end surface 546 of the relay board 540 is fixed opposite the first surface 512 of the conductive block 510. A conductive adhesive may be used for fixing. The first conductor 580 is electrically connected to the conductive block 510.

The relay substrate 540 has a second conductor 584 (e.g., a buried via). The second conductor 584 is embedded in the relay substrate 540 (insulating layer) and is connected to the first ground pattern 564. The second conductor 584 has a second exposed surface 586 exposed at the second end surface 548. The second end surface 548 is opposite the first end surface 546.

The optical module has a conductive piece 588. The conductive piece 588 is made entirely of a conductive material. At least the surface of the conductive piece 588 is made of a conductive material and is electrically connected to the second exposed surface 586 of the second conductor 584 in surface contact. One end of the ground wire 576 is bonded to the surface of the conductive piece 588. The ground wire 576 is electrically connected to the first ground pattern 564 via the conductive piece 588. The other end of the ground wire 576 is connected to the support block 590. As for other details, what has been described in the second embodiment can be applied to this embodiment.

Sixth embodiment
Fig. 12 is a perspective view showing a part of an optical module according to a sixth embodiment. Fig. 13 is a cross-sectional view showing a part of an optical module according to a sixth embodiment. In this embodiment, the relay substrate 540 (Fig. 11) described in the fifth embodiment is used.

This embodiment differs from the fifth embodiment (FIG. 9) in the conductive piece 688. The conductive piece 688 includes a body 692 made of an insulating material. The body 692 is a polyhedron having multiple flat surfaces. The conductive piece 688 includes a metal film 694 formed on the body 692.

A portion 694a of the metal film 694 is formed on the surface of the main body 692 facing the second end surface 548. In other words, the portion 694a of the metal film 694 is a connection portion with the second exposed surface 586 of the second conductor 584. The conductive piece 688 is electrically connected to the first ground pattern 564 via the second conductor 584.

The other part 694b of the metal film 694 is formed on the surface of the main body 692 opposite the surface facing the second end surface 548. The other part 694b of the metal film 694 does not face the second end surface 548 of the relay substrate 540. The metal film 694 is formed over three or more surfaces of the main body 692 and is continuous and integrated.

The other part 694b of the metal film 694 is the bonding part of the ground wire 576. The ground wire 576 is electrically connected to the second conductor 584 via the metal film 694. The ground wire 576 transmits the ground potential to the support block 590, stabilizing the ground potential. As shown in FIG. 12, the metal layer 682 of the thermoelectric cooler 680 and the conductive block 610 are connected by a wire W8, which also strengthens the ground.

The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the configurations described in the embodiments can be replaced with substantially the same configurations, configurations that provide the same effects, or configurations that can achieve the same objectives.

10 Conductive block, 12 First surface, 14 Second surface, 16 Through hole, 18 Base portion, 20 Insulating material, 22 Signal lead, 24 Holding portion, 26 Photoelectric element, 28 Mounting substrate, 30 Bypass capacitor, 32 Wiring pattern, 34 Ground electrode, 36 Side electrode, 38 Signal electrode, 40 Relay substrate, 42 Front surface, 44 Back surface, 46 First end surface, 48 Second end surface, 50 Inclined surface, 52 Conductive adhesive, 54 Conductor layer, 56 Insulating layer, 58 Signal pattern, 60 Signal line, 62 Pad portion, 64 First ground pattern, 66 Second ground pattern, 68 First via, 70 Third ground pattern, 72 Second via, 74 Signal wire, 76 Ground wire, 78 Capillary, 100 Optical module, 102 Flexible substrate, 210 Conductive block, 212 First surface, 280 Thermoelectric cooler, 282 Metal layer, 284 Support block, 310 Conductive block, 316 Through hole, 320 Insulating material, 322 Signal lead, 326 Photoelectric element, 328 Mounting substrate, 332 Wiring pattern, 340A First relay substrate, 340B Second relay substrate, 352 Conductive adhesive, 358 Signal pattern, 386 Differential signal wiring, 440 Relay substrate, 442 Surface, 450 Inclined surface, 458 Signal pattern, 510 Conductive block, 512 First surface, 540 Relay substrate, 546 First end surface, 548 Second end surface, 564 First ground pattern, 576 Ground wire, 580 First conductor, 582 First exposed surface, 584 Second conductor, 586 Second exposed surface, 588 Conductive piece, 590 Support block, 610 Conductive block, 680 Thermoelectric cooler, 682 metal layer, 688 conductive piece, 692 body, 694 metal film, 694a part, 694b other part, L lead, OX optical axis, W wire, W1 wire, W2 wire, W3 wire, W4 wire, W5 wire, W6 wire, W7 wire, W8 wire.

Claims (21)

a conductive block having a first surface and a second surface and a plurality of through holes extending between the first surface and the second surface;
a plurality of leads including signal leads, the leads being fixed inside the plurality of through holes while being insulated from the conductive block;
a relay board having two or more layers, the relay board having a structure in which a plurality of conductor layers are disposed with insulating layers interposed therebetween;
a photoelectric element for converting at least one of an optical signal and an electrical signal to the other;
a plurality of wires including a signal wire;
having
the relay board has a first end face fixed to face the first face of the conductive block, a second end face opposite the first end face, and a front surface and a back surface that define a thickness of the relay board between the first end face and the second end face;
the surface has an inclined surface that is inclined such that the thickness decreases from the first end surface toward the second end surface, at least at a position closer to the first end surface than the second end surface;
the plurality of conductor layers include a signal pattern located on the front surface such that a portion of the signal pattern is disposed on the inclined surface, and a first ground pattern located from the back surface to each of the first end surface and the second end surface,
an optical module, wherein the signal wire has one end bonded to the signal lead and the other end bonded to the signal pattern on the inclined surface; 2. The optical module according to claim 1,
The optical module according to claim 1, wherein the plurality of conductor layers include a second ground pattern located on an inner layer of an intermediate substrate and electrically connected to the first ground pattern. 3. The optical module according to claim 1,
the plurality of wires includes a ground wire,
the ground wire has one end bonded to the first ground pattern at the second end surface. 4. An optical module according to claim 3,
the conductive block has a protruding base portion on the first surface,
The other end of the ground wire is bonded to the base portion. 5. The optical module according to claim 1,
an electrically conductive adhesive interposed between the first surface and the first end surface, electrically connecting the first ground pattern to the conductive block and fixing the relay substrate to the conductive block. 6. The optical module according to claim 1,
The optical module according to claim 1, wherein the intermediate substrate is supported by the conductive block only at the first end surface. 7. The optical module according to claim 1,
An optical module, wherein at least a portion of the relay substrate does not overlap any of the plurality of through holes. 8. The optical module according to claim 1,
An optical module, wherein the signal wire is bonded to a tip surface of the signal lead. 9. An optical module according to claim 8,
the signal lead has a holding portion located inside one of the plurality of through holes;
An optical module, wherein the tip surface is larger in diameter than the holding portion. 10. The optical module according to claim 1,
The optical module according to claim 1, wherein the plurality of wires further includes a wire bonded to the signal pattern on the surface. 11. The optical module according to claim 1,
The optical module according to claim 1, wherein the signal pattern includes a signal line and a pad portion located on the inclined surface and having a width larger than a wiring width of the signal line. 12. The optical module according to claim 1,
The optical module according to claim 1, wherein the first ground pattern is positioned so as to extend from the rear surface to the second end surface. 13. An optical module according to claim 12,
The first ground pattern extends beyond the second end face to reach the front surface. 14. An optical module according to claim 13,
The optical module according to claim 1, wherein the plurality of wires further includes a wire bonded to the first ground pattern on the front surface. 11. The optical module according to claim 1,
each of the first relay substrate and the second relay substrate is the relay substrate,
an optical module, wherein a differential transmission line is formed by the signal pattern of the first relay board and the signal pattern of the second relay board. a conductive block having a first surface and a second surface and a plurality of through holes extending between the first surface and the second surface;
a plurality of leads including signal leads, the leads being fixed inside the plurality of through holes while being insulated from the conductive block;
a relay board having two or more layers, the relay board having a structure in which a plurality of conductor layers are disposed with insulating layers interposed therebetween;
a photoelectric element for converting at least one of an optical signal and an electrical signal to the other;
a plurality of wires including a signal wire;
having
the relay board has a first end face fixed to face the first face of the conductive block, a second end face opposite the first end face, and a front surface and a back surface that define a thickness of the relay board between the first end face and the second end face;
the surface has an inclined surface that is inclined such that the thickness decreases in a direction from the first end surface to the second end surface,
the plurality of conductor layers include a signal pattern located on the inclined surface, a first ground pattern located on the back surface, and a first conductor embedded in the relay board and connected to the first ground pattern so as to have a first exposed surface exposed on the first end surface,
an optical module, wherein the signal wire has one end bonded to the signal lead and the other end bonded to the signal pattern on the inclined surface; 17. An optical module according to claim 16,
an optical module characterized in that the plurality of conductor layers further include a second conductor embedded in the relay substrate so as to have a second exposed surface exposed at the second end surface and connected to the first ground pattern. 18. An optical module according to claim 17,
a conductive piece having at least a surface made of a conductive material and in surface contact with the second exposed surface of the second conductor;
The optical module according to claim 1, wherein the plurality of wires includes a ground wire having one end bonded to the surface of the conductive piece. 20. The optical module according to claim 18,
An optical module, wherein the conductive piece is made entirely of the conductive material. 20. The optical module according to claim 18,
The conductive piece includes a body made of an insulating material and a metal film formed on the body,
a portion of the metal film is a connection portion with the second exposed surface,
the other part of the metal film does not face the second end face and is a bonding portion of the ground wire. 21. The optical module according to claim 18,
a mounting substrate on which the photoelectric element is mounted;
a support block for supporting the mounting substrate, the support block being made of a conductive material and having the other end of the ground wire bonded thereto;
4. An optical module further comprising:

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