JP2019153674A - Optical module - Google Patents

Abstract

To suppress the deterioration of high frequency characteristics.SOLUTION: An optical module includes: an optical subassembly 10 that converts an optical communication signal and an electrical communication signal from at least one to the other; a rigid substrate 14 having a first wiring pattern 18; and a flexible substrate 16 having a second wiring pattern 36. The rigid substrate 14 and the flexible substrate 16 are electrically connected to each other. The optical subassembly 10 is electrically connected to at least the first wiring pattern 18. A communication wiring 20 for transmitting an electrical communication signal is included only in the first wiring pattern 18.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an optical module.

  Optical modules used for optical communication have been reduced in size, functionality, and density. A plurality of integrated circuit chips are used for operation and control, and they are mounted on a printed circuit board (PCB) in the optical module. With the recent increase in functionality, the necessity of arranging electronic components / wirings including a larger number of integrated circuit chips on the PCB has increased as compared with the prior art, and a single PCB is not sufficient, and light using a plurality of PCBs is required. A module is known (Patent Document 1). However, in Patent Document 1, a connector provided on the PCB is used for the plurality of PCBs. An optical module in which a plurality of PCBs are connected using a flexible substrate (FPC) is known (Patent Document 2). Furthermore, there is also known a technique that secures a mounting area for electronic components by bending and using a long FPC (Patent Document 3).

JP 2014-67835 A Japanese Patent Laid-Open No. 11-177278 JP 2006-86433 A

  When a plurality of PCBs are connected using a connector or FPC, an electronic component cannot be arranged in an area for connecting the connector or FPC, which hinders high-density mounting. Further, the wiring for transmitting a high-frequency signal for communication passes through both the plurality of PCBs and the FPC in Patent Document 1, and passes between both ends in the longitudinal direction of the FPC in Patent Document 3. Therefore, since the wiring is long, it is disadvantageous in high frequency characteristics.

  The optical module is required to have a rigid structure called a card edge in connection with a host device according to a standard such as MSA (Multi Source Agreement). Therefore, the FPC cannot be directly connected to the host device, and the card edge connector must be connected to the FPC as shown in Patent Document 2. The connecting portion prevents miniaturization.

  An object of the present invention is to realize high-density mounting and suppress deterioration of high-frequency characteristics.

  (1) An optical module according to the present invention includes an optical subassembly for converting an optical communication signal and an electric communication signal from at least one to the other, a rigid substrate having a first wiring pattern, and a flexible having a second wiring pattern. A substrate, wherein the rigid substrate and the flexible substrate are electrically connected, and the optical subassembly is electrically connected to at least the first wiring pattern, and transmits the electrical communication signal. The communication wiring is characterized by being included only in the first wiring pattern.

  According to the present invention, since the wiring for transmitting the telecommunication signal does not become long, it is possible to suppress the deterioration of the high frequency characteristics.

  (2) The optical module according to (1), wherein the first wiring pattern includes a first terminal and a second terminal that are respectively positioned at opposite ends of the rigid substrate. The terminal is a part of the communication wiring and is connected to the optical subassembly, and the second terminal is another part of the communication wiring for external input / output of the telecommunication signal. It may be a feature.

  (3) The optical module according to (2), further including a first integrated circuit chip for processing the telecommunication signal, wherein the first integrated circuit chip is mounted on the rigid substrate, The communication terminal may be electrically connected between the first terminal and the second terminal.

  (4) In the optical module according to (2) or (3), the first wiring pattern includes a third terminal to be electrically connected to the second wiring pattern, and the third terminal is The rigid substrate may be located on at least one of both sides orthogonal to the direction between the both ends, avoiding the both ends.

  (5) The optical module according to any one of (1) to (4), wherein the optical subassembly is also electrically connected to the second wiring pattern, and the second wiring pattern is: Control wiring for transmitting a control signal of the optical subassembly may be included.

  (6) The optical module according to (5), further including a second integrated circuit chip for controlling the optical subassembly, wherein the second integrated circuit chip is mounted on the flexible substrate, It may be electrically connected to the control wiring.

  (7) The optical module according to any one of (1) to (6), wherein the flexible substrate is bent and is located at least one above and below the front and back surfaces of the rigid substrate It is good also as having.

It is a perspective view of the optical module which concerns on embodiment of this invention. It is the schematic of the II-II sectional view of the optical module shown in FIG. It is a top view which shows the surface side of a rigid board | substrate. It is a top view which shows the back surface side of a rigid board | substrate. It is a top view of an optical subassembly. It is an expanded view which shows the bending inner surface of a flexible substrate. It is an enlarged view of the VII-VII line cross section of the optical module shown in FIG. It is an enlarged view of the VIII-VIII line cross section of the optical module shown in FIG. It is an enlarged view of the IX-IX line cross section of the optical module shown in FIG. It is an enlarged view of the XX line cross section of the optical module shown in FIG. It is a perspective view of the optical module which concerns on the modification 1 of embodiment. It is the schematic of the optical module which concerns on the modification 2 of embodiment. It is the schematic of the optical module which concerns on the modification 3 of embodiment. It is the schematic of the optical module which concerns on the modification 4 of embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, about drawing, the same code | symbol is attached | subjected to the same or equivalent element, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a perspective view of an optical module according to an embodiment of the present invention. The optical module has an optical subassembly 10. The optical subassembly 10 converts an optical communication signal and an electric communication signal from at least one to the other. The optical module is a transceiver (optical transceiver module) including an optical sub-assembly (TOSA) 10A having an optical transmission function and an optical sub-assembly (ROSA) 10B having an optical reception function. It is.

  The optical module exchanges telecommunication signals (high frequency signals) with an external host device. An electrical communication signal input from the host device is subjected to signal conversion processing, input to an optical subassembly (TOSA) 10A, converted into an optical communication signal, and output through a receptacle 12A optically connected to an optical fiber. The On the other hand, an optical communication signal input from a receptacle 12B optically connected to an optical fiber is input to an optical subassembly (ROSA) 10B, converted into an electric communication signal, subjected to processing such as amplification, and an external host. Output to the device. The optical subassembly 10 is electrically connected to at least one (for example, both) of the rigid substrate 14 and the flexible substrate 16.

  2 is a schematic view of a cross section taken along line II-II of the optical module shown in FIG. The optical module has a rigid substrate 14. The rigid substrate 14 is a multilayer substrate having a plurality of wiring layers as inner layers on a base made of glass epoxy. The rigid substrate 14 has first front and back surfaces 14a and 14b. The rigid substrate 14 has a first end surface 14c on the periphery of the first front and back surfaces 14a and 14b so as to surround them.

  FIG. 3 is a plan view showing the first surface 14 a side of the rigid substrate 14. FIG. 4 is a plan view showing the first back surface 14 b side of the rigid substrate 14. The rigid substrate 14 has a first wiring pattern 18. The first wiring pattern 18 is composed of multiple layers, and vias (not shown) are used to connect different layers. The first wiring pattern 18 includes an inner layer wiring and may include a surface layer wiring, and these are shown in FIG. 3 and FIG. 4 without distinction.

The optical subassembly 10 shown in FIG. 1 is electrically connected to at least the first wiring pattern 18. Communication wirings 20 for transmitting electrical communication signals are included in the first wiring pattern 18. The first wiring pattern 18 includes a first terminal 22 and a second terminal 24. The first terminal 22 and the second terminal 24 are located at both ends of the rigid substrate 14 opposite to each other in the length direction. The first terminal 22 is a part of the communication wiring 20 and is connected to the optical subassembly 10. The second terminal 24 is another part of the communication wiring 20 and is used for external input / output of telecommunication signals, and is included in the plurality of external terminals T _out .

  A first integrated circuit chip 26 is mounted on the rigid substrate 14 (for example, the first surface 14a thereof). The first integrated circuit chip 26 is for processing input / output telecommunication signals. For example, a digital signal processor. The first integrated circuit chip 26 is electrically connected to the communication wiring 20 between the first terminal 22 and the second terminal 24. A heat sink 28 is attached to the first integrated circuit chip 26.

A power supply IC chip 30 is mounted on the rigid substrate 14 (for example, the first back surface 14b). Power IC chip 30 is for supplying a predetermined power supply voltage, is connected to the wiring I _pw extending from the external terminal T _out. The power supply IC chip 30 is not connected to the first integrated circuit chip 26, but is connected to other components (for example, the second integrated circuit chip 32 and the processor chip 34 shown in FIG. 2). The power supply IC chip 30 and the first integrated circuit chip 26 may be connected. Although the power supply IC chip 30 is described as a single chip here, it may be a circuit composed of a plurality of ICs or electronic components having equivalent functions.

  The 1st wiring pattern 18 contains the 3rd terminal 38 for electrically connecting to the 2nd wiring pattern 36 (FIG. 6) mentioned later. The third terminals 38 are on at least one side (for example, both sides) of both sides in the direction (width direction) orthogonal to the direction between the both ends (length direction), avoiding both ends in the length direction of the rigid substrate 14. . For example, the third terminal 38A connected to the first integrated circuit chip 26 and the third terminals 38B and 38C connected to the power supply IC chip 30 are electrically connected to the second wiring pattern 36 (FIG. 6). The third terminal 38 includes a pair of pads on the first front and back surfaces 14a and 14b of the rigid board 14, and both are connected by vias (see FIGS. 7 to 9).

  FIG. 5 is a plan view of the optical subassembly 10. The optical module has a flexible substrate 16. The flexible substrate 16 is a multilayer substrate having flexibility and having a plurality of wiring layers as inner layers on a base made of resin such as polyimide resin. The flexible substrate 16 is bent as shown in FIG. 2, and has a portion located on at least one (for example, both) above and below the first front and back surfaces 14 a and 14 b of the rigid substrate 14. The flexible substrate 16 has second front and back surfaces 16a and 16b. The flexible substrate 16 has a hole 40 (FIGS. 1 and 5) for avoiding the heat sink 28 attached to the first integrated circuit chip 26.

  FIG. 6 is a development view showing the bent inner surface (second back surface 16 b) of the flexible substrate 16. The flexible substrate 16 has a second wiring pattern 36. The second wiring pattern 36 includes an inner layer wiring and may include a surface layer wiring, and these are shown in FIG. 6 without distinction. The optical subassembly 10 is also electrically connected to the second wiring pattern 36 (see FIG. 1). The second wiring pattern 36 includes the control wiring 42 for transmitting the control signal of the optical subassembly 10, but does not include the wiring for transmitting the telecommunication signal. That is, neither the telecommunication signal converted from the optical communication signal nor the telecommunication signal for converting to the optical communication signal passes through the flexible substrate 16 (second wiring pattern 36). Therefore, since the wiring for transmitting the telecommunication signal does not become long, the deterioration of the high frequency characteristics can be suppressed.

A second integrated circuit chip 32 is mounted on the flexible substrate 16 (for example, the second back surface 16b). The second integrated circuit chip 32 is for controlling the optical subassembly 10. The second integrated circuit chip 32 is electrically connected to the control wiring 42. The optical subassembly 10 is electrically connected to the terminal of the control wiring 42. A processor chip 34 is mounted on the flexible substrate 16 (for example, the second surface 16a). The processor chip 34 has a function as a microcomputer. The processor chip 34 is connected to and controls the second integrated circuit chip 32. The connection is made by the wiring I _α of the second wiring pattern 36.

  The flexible substrate 16 is fixed and electrically connected to the rigid substrate 14. That is, the second wiring pattern 36 is electrically connected to the first wiring pattern 18. A connector 44 is used for fixing and electrical connection (FIG. 2).

The processor chip 34 is connected to and controls the first integrated circuit chip 26 (FIG. 3). Therefore, the wiring I _X ′ connected to the processor chip 34 has a terminal T ₁ . Terminal _{T 1} is connected via the connector 44A to the third terminal 38A (FIG. 3).

The processor chip 34 is connected to the power supply IC chip 30 (FIG. 4) to obtain power. Therefore, the wiring I _Y ′ connected to the processor chip 34 has a terminal T ₂ . Terminal _{T 2} are, are connected via a connector 44B to the third terminal 38B (Fig. 4).

The second integrated circuit chip 32 is connected to the power supply IC chip 30 (FIG. 4) to obtain power. Therefore, the wiring I _Z ′ connected to the second integrated circuit chip 32 has a terminal T ₃ . Terminal _{T 3} is connected via a connector 44A to the third terminal 38C (FIG. 4).

  FIG. 7 is an enlarged view of a cross section taken along line VII-VII of the optical module shown in FIG. FIG. 8 is an enlarged view of a cross section taken along line VIII-VIII of the optical module shown in FIG. FIG. 9 is an enlarged view of a cross section taken along line IX-IX of the optical module shown in FIG. FIG. 10 is an enlarged view of a cross section taken along line XX of the optical module shown in FIG.

The base of the connector 44 is made of resin. A third wiring pattern 46 is provided on the base along its outer shape. The metal film constituting the third wiring pattern 46 does not cover the entire surface of the base. The connector 44 has a recess 48 to be inserted and held at the end of the rigid board 14. The connector 44 is flat on the opposite side of the recess 48. The third wiring pattern 46 includes a plurality of wirings I ₁ , I ₂ , I ₃ extending from the inside of the recess 48 to the opposite side of the recess 48.

7, the wiring I ₁ for connecting the third terminal 38A and the terminal T ₁ is shown for connection of the first integrated circuit chip 26 and the processor chip 34. Wire _{I X} of the first wiring pattern 18 is connected to the first integrated circuit chip 26, it is connected to the wiring _{I 1} at the third terminal 38A. The wiring I _X ′ of the second wiring pattern 36 is connected to the processor chip 34 and is connected to the wiring I ₁ at the terminal T ₁ . Solder 50 is used for connection.

Figure 8 is a wiring _{I 2} for connecting the third terminal 38B and the terminal _{T 2} is shown for connection of the power supply IC chip 30 and the processor chip 34. The wiring I _Y of the first wiring pattern 18 is connected to the power supply IC chip 30 and is connected to the wiring I ₂ at the third terminal 38B. The wiring I _Y ′ of the second wiring pattern 36 is connected to the processor chip 34 and is connected to the wiring I ₂ at the terminal T ₂ . Solder 50 is used for connection.

9 shows the wiring _{I 3} for connecting the third terminal 38C and the terminal _{T 3} is shown for connection of the power supply IC chip 30 and the second integrated circuit chip 32. Wire _{I Z} of the first wiring pattern 18 is connected to the power supply IC chip 30 is connected to the wiring _{I 3} at the third terminal 38C. The wiring I _Z ′ of the second wiring pattern 36 is connected to the second integrated circuit chip 32 and is connected to the wiring I ₃ at the terminal T ₃ . Solder 50 is used for connection. In FIG. 10, the wiring Iα (see FIGS. 5 and 6) of the second wiring pattern 36 connects the upper and lower components (the second integrated circuit chip 34 and the processor chip 32) without using the connector 44. It is shown.

  A connector 44 is fixed to the rigid board 14. The first fixing region 52 to which the connector 44 is fixed is on at least one of the first front and back surfaces 14a and 14b. The first fixing region 52 is on at least one of the opposite sides of the rigid substrate 14. A pair of first fixing regions 52 </ b> A and 52 </ b> B are provided on both sides of the rigid substrate 14 opposite to each other. A pair of connectors 44A and 44B are fixed to the pair of first fixing regions 52A and 52B, respectively. The connector 44 has a surface facing the first fixed region 52. The connector 44 faces the first end face 14c.

  A connector 44 is fixed to the flexible substrate 16. The second fixing region 54 to which the connector 44 is fixed is on at least one of the second front and back surfaces 16a and 16b (for example, the inner surface of the bend). The second fixed region 54 extends along a direction intersecting the first fixed region 52. The second fixed region 54 is outside the rigid substrate 14 in the direction along the first front and back surfaces 14a and 14b. The second fixed region 54 faces the first end surface 14c.

  As shown in FIG. 6, there is a second fixing region 54 </ b> A on at least one (for example, only one) of both sides of the flexible substrate 16 opposite to each other. There is also a second fixed region 54B between the opposite sides of the flexible substrate 16. The flexible substrate 16 includes a pair of second fixing regions 54A and 54B. The pair of second fixing regions 54 </ b> A and 54 </ b> B is located at one of the opposite sides of the flexible substrate 16 and between the both sides. The pair of connectors 44A and 44B are fixed to the pair of second fixing regions 54A and 54B, respectively. The connector 44 has a surface facing the second fixed region 54.

  According to this embodiment, as shown in FIGS. 7 to 9, since the second fixing region 54 is outside the rigid board 14, the mounting area of the connector 44 on the rigid board 14 can be reduced, and the rigid board 14. More ICs, electronic parts, and wiring patterns can be provided on the top, and high-density mounting can be realized. Furthermore, electronic components etc. are arranged directly on the surface of the FPC arranged above and below the PCB, and the number of connection points between the PCB and the FPC can be reduced compared to the case where all the wiring boards used are PCBs. Only the parts placement area is secured. Further, by configuring the upper and lower FPCs as one piece, it is possible to transmit signals between the second integrated circuit chip 32 and the processor chip 34 without using the rigid substrate 14, and to reduce the wiring / connector area on the PCB accordingly. Can do. As a result, the optical module can be miniaturized.

  The connector 44 is attached as follows. The flexible substrate 16 is prepared in the unfolded state as shown in FIG. A pair of connectors 44 </ b> A and 44 </ b> B are fixed to the flexible substrate 16. For fixing, solder 50 may be used and a reflow method may be applied. And the one side of the rigid board | substrate 14 is fixed to the connector 44A attached to the one side of the flexible substrate 16 (FIG. 7 or FIG. 8). Solder 50 is used for fixing, and a tool such as a soldering iron is used. Next, the flexible substrate 16 is bent, and the connector 44B attached to the center (between both sides) of the flexible substrate 16 is fixed to the other side of the rigid substrate 14 (FIG. 9). Solder 50 is used for fixing, and a tool such as a soldering iron is used. As shown in FIG. 9, since the first surface 14a side of the rigid substrate 14 is covered with the flexible substrate 16 and the soldering iron does not enter, the soldering 50 is performed only on the first back surface 14b side.

[Modification 1]
FIG. 11 is a perspective view of an optical module according to Modification 1 of the embodiment. In the first modification, no heat sink is attached to the first integrated circuit chip 126. Therefore, the flexible substrate 116 does not have a hole for avoiding the heat sink. Other contents correspond to the contents of the embodiment.

[Modification 2]
FIG. 12 is a schematic diagram of an optical module according to Modification 2 of the embodiment. In the second modification, the rigid substrate 214 has a first fixed region 252 on one side. The flexible substrate 216 has a second fixed region 254 on one side. One connector 244 fixes and electrically connects the rigid board 214 and the flexible board 216. Other contents correspond to the contents of the embodiment.

[Modification 3]
FIG. 13 is a schematic diagram of an optical module according to Modification 3 of the embodiment. In the third modification, the rigid substrate 314 has first fixing regions 352 on both sides opposite to each other. A pair of connectors 344A and 344B are attached to the pair of first fixing regions 352A and 352B, respectively. Separate flexible boards 316A and 316B are attached to the connectors 344A and 344B, respectively. That is, a pair of flexible substrates 316A and 316B is used. The flexible substrate 316 has a second fixed region 354 on one side. A connector 344 fixes and electrically connects the rigid board 314 and the flexible board 316. Other contents correspond to the contents of the embodiment.

[Modification 4]
FIG. 14 is a schematic diagram of an optical module according to Modification 4 of the embodiment. In the modified example 4, the rigid substrate 414 has a first fixing region 452 on one side. The flexible substrate 416 has a second fixing region 454 at the opposite center (between both sides). One connector 444 fixes and electrically connects the rigid board 414 and the flexible board 416. Other contents correspond to the contents of the embodiment.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the configuration described in the embodiment can be replaced with substantially the same configuration, a configuration that exhibits the same operational effects, or a configuration that can achieve the same purpose.

DESCRIPTION OF SYMBOLS 10 Optical subassembly, 10A optical subassembly, 10B optical subassembly, 12A receptacle, 12B receptacle, 14 Rigid board | substrate, 14a 1st surface, 14b 1st back surface, 14c 1st end surface, 16 Flexible substrate, 16a 2nd surface, 16b 2nd back surface, 18 1st wiring pattern, 20 communication wiring, 22 1st terminal, 24 2nd terminal, 26 1st integrated circuit chip, 28 heat sink, 30 power supply IC chip, 32 2nd integrated circuit chip, 34 processor chip 36, second wiring pattern, 38 third terminal, 38A third terminal, 38B third terminal, 38C third terminal, 40 holes, 42 control wiring, 44 connector, 44A connector, 44B connector, 46 third wiring pattern, 48 Recess, 50 solder, 52 first fixed area, 52A first fixed area, 52B first fixed area Fixed region, 54 Second fixed region, 54A Second fixed region, 54B Second fixed region, 116 Flexible substrate, 126 First integrated circuit chip, 214 Rigid substrate, 216 Flexible substrate, 244 Connector, 252 First fixed region, 254 Second Fixed Area, 314 Rigid Board, 316 Flexible Board, 316A Flexible Board, 316B Flexible Board, 344 Connector, 344A Connector, 344B Connector, 352 First Fixed Area, 352A First Fixed Area, 352B First Fixed Area, 354 First 2 fixed region, 414 rigid substrate, 416 flexible substrate, 444 connector, 452 first fixed region, 454 second fixed region, I _α wiring, I ₁ wiring, I ₂ wiring, I ₃ wiring, I _X wiring, I _Y wiring , _{I Z} wire, _{I X} 'lines, _{I Y'} line, _{Z 'lines, I pw} wiring, _{T 1} terminal, _{T 2} terminal, _{T 3 terminal, T out} external terminal.

Claims (7)

An optical subassembly for converting at least one optical communication signal and telecommunication signal from one to the other;
A rigid substrate having a first wiring pattern;
A flexible substrate having a second wiring pattern;
Have
The rigid substrate and the flexible substrate are electrically connected,
The optical subassembly is electrically connected to at least the first wiring pattern;
The optical module, wherein the communication wiring for transmitting the telecommunication signal is included only in the first wiring pattern. The optical module according to claim 1,
The first wiring pattern includes a first terminal and a second terminal respectively positioned at opposite ends of the rigid substrate.
The first terminal is a part of the communication wiring and is connected to the optical subassembly;
The optical module, wherein the second terminal is another part of the communication wiring and is used for external input / output of the telecommunication signal. The optical module according to claim 2,
A first integrated circuit chip for processing the telecommunications signal;
The optical module, wherein the first integrated circuit chip is mounted on the rigid substrate and is electrically connected to the communication wiring between the first terminal and the second terminal. The optical module according to claim 2 or 3, wherein
The first wiring pattern includes a third terminal for electrically connecting to the second wiring pattern,
The optical module according to claim 1, wherein the third terminal is located on at least one of both sides orthogonal to a direction between the both ends, avoiding the both ends of the rigid substrate. The optical module according to any one of claims 1 to 4, wherein:
The optical subassembly is also electrically connected to the second wiring pattern;
The optical module, wherein the second wiring pattern includes a control wiring for transmitting a control signal of the optical subassembly. The optical module according to claim 5,
A second integrated circuit chip for controlling the optical subassembly;
The optical module, wherein the second integrated circuit chip is mounted on the flexible substrate and electrically connected to the control wiring. The optical module according to any one of claims 1 to 6,
The optical module is characterized in that the flexible substrate has a portion that is bent and located at least one of the upper and lower surfaces of the rigid substrate.

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