Patent Application
20140205248
The present invention relates to an optical transmitter/receiver apparatus and a method of manufacturing the same.
Optical transmitter/receiver apparatuses such as optical transceivers each include respective components and a case that houses the components. Examples of the components include a circuit board, an optical receiver module and a light-emitting module. In many cases, optical transmitter/receiver apparatuses are mounted on boards housed side by side in a rack cabinet. Thus, the cases of the optical transmitter/receiver apparatuses are subject to limitations in outer shape, and the cases generally have flat plate-like shapes. The outer sizes of the optical transmitter/receiver apparatuses are prescribed by industrial standards called “MSA” (Multi-Source Agreement). In order to provide functions prescribed by the MSA standards, optical transmitter/receiver apparatuses each include a multitude of components.
JP 2005-197569A (hereinafter referred to as Patent Literature 1) discloses an optical transmission module (optical transmitter/receiver apparatus) in which a circuit board, an optical receiver module that receives an optical signal, and an optical transmitter module that transmits an optical signal are directly fixed to a case. Consequently, heat generated from the circuit board, the optical receiver module and the optical transmitter module is radiated from the case.
JP 2006-171398A (hereinafter referred to as Patent Literature 2) describes that a substrate is not fixed to a case and that a predetermined surface of an optical module comes into contact with a predetermined surface of the case and that the optical module is fixed to the case. Heat generated from the optical module is released through the case.
JP 2008-203427A (hereinafter referred to as Patent Literature 3) discloses an optical module (optical transmitter/receiver apparatus) including an optical assembly that houses an optical element to/from which an optical signal is input/output, and a circuit board electrically connected to the optical assembly. The optical assembly is arranged at a predetermined distance from the circuit board, and is electrically connected to the circuit board. The optical assembly is housed in a case. Between the optical assembly and the case, an elastic member having a heat dissipation property is provided. The optical assembly is fixed to the case via the elastic member. More specifically, the case includes an upper case and a lower case resulting from the case being separated into two parts that are upper and lower parts, and the optical assembly is fixed to the upper case via the elastic member. Furthermore, the circuit board is fixed to the upper case by screws being threadably fitted in screw holes in board support pillars. Heat generated from the optical assembly is radiated from the upper case.
In recent years, with a decrease in size, an increase in capacity and enhancement of functions, the densities of components mounted in optical transmitter/receiver apparatuses are becoming higher and higher. In particular, optical transmitter/receiver apparatuses that support 100 Gbps or 40 Gbps digital coherent communications have a large number of components included in the optical transmitter/receiver apparatuses, requiring further higher density mounting. Also, with high density mounting in optical transmitter/receiver apparatuses, enhancement in heat dissipation efficiency of the respective components is demanded. In particular, electric components in digital signal processors such as LSI generate a large amount of heat, and it is desired to suppress the influence of heat from such electric components on the optical module.
It is necessary to house a circuit board and an optical module in a case having a predetermined size. Thus, a part of the circuit board is cut out to secure a space where the optical module is arranged. As described above, an optical transmission module according to each of Patent Literatures 1 and 2, the size of the circuit board is limited because of the cutout in the circuit board (see FIG. 2 in Patent Literature 1 and FIG. 10 in Patent Literature 2). Consequently, the problem of a decrease in mounting area of the circuit board has arisen.
In the optical module described in Patent Literature 3, both the circuit board and the optical assembly are fixed to the upper case. Thus, heat conducted from the optical module to the upper case may be transferred to the circuit board or heat conducted from the circuit board to the upper case may be transferred to the optical module. Thus, the heat dissipation propert(ies) of the circuit board and/or the optical module may deteriorate.
Accordingly, it is desired to provide an optical transmitter/receiver apparatus that can, while securing a sufficient mounting area of a circuit board, enhance the heat dissipation propert(ies) of the circuit board and/or an optical module and a method for manufacturing the same.
An optical transmitter/receiver apparatus according to an exemplary embodiment includes a case including a base and a cover, a circuit board and an optical module. The circuit board is housed in the case and is fixed to the base. The optical module is housed in the case, is arranged on a side opposite to the base relative to the circuit board, and is fixed to the cover.
A method of manufacturing an optical transmitter/receiver apparatus according to an exemplary embodiment includes the steps of: fixing a circuit board to a base, placing an optical module on the circuit board, and placing a cover on the base and fastening a screw from outside of the cover to fix the optical module to the cover side.
The above configuration enables heat dissipation properties of a circuit board and an optical module to be enhanced while a sufficient mounting area of the circuit board is secured.
The above object and other objects, features and advantages of the present invention will be clarified in the below description with reference to the accompanying drawings illustrating examples of the present invention.
An exemplary embodiment of the present invention will be described below with reference to the drawings. The present invention is applicable to optical transmitter/receiver apparatuses including a circuit board and an optical module in general.
An optical transmitter/receiver apparatus includes a case that houses various components, a circuit board and an optical module.
Optical module 3 includes, for example, a laser module and peripheral circuits. Optical module 3 is arranged at a position closer to cover 8 relative to circuit board 1, the position being at a distance from circuit board 1. Optical module 3 is electrically connected to circuit board 1 via, for example, flexible wiring board 18. More specifically, connector 11 provided at flexible wiring board 18 and connector 12 provided at circuit board 1 are connected to each other.
Optical fiber 14 extends from optical module 3. In the example illustrated in
Optical module 3 is fixed to cover 8 via plate 6. Optical module 3 is fixed to plate 6 via fixing members 4 such as, for example, screws. Plate 6 is provided between optical module 3 and cover 8, and is directly fixed to cover 8 via screws 10. More specifically, through holes 9 for fixing plate 6 via screws 10 are provided in cover 8. In plate 6, screw holes 13 are provided at positions corresponding to through holes 9 of cover 8. As described above, in the present exemplary embodiment, optical module 3 is fixed to cover 8 side via plate 6. Alternatively, optical module 3 may be directly fixed to cover 8 via, for examples, screws.
From the perspective of heat dissipation properties, it is preferable that each of base 7 and cover 8 are made of a metal. For heat dissipation property enhancement, a plurality of grooves may be formed at an outer surface of cover 8. Base 7 and cover 8 have a function that radiates heat conducted from circuit board 1 and optical module 3. In the present exemplary embodiment, circuit board 1 is fixed to the base 7 side and optical module 3 is fixed to the cover 8 side, enabling heat from both circuit board 1 and optical module 3 to be efficiently released.
Circuit board 1 and optical module 3 are spaced apart from each other, and an air layer is present between circuit board 1 and optical module 3. The air layer also enables prevention of the influence of heat generated from electric components mounted on circuit board 1 on the optical module. In particular, if the optical module is an optical module having a light emission function, for example, a high-power laser module for long-distance transmission or a wavelength-variable light source module, it is preferable that the optical module be provided at a distance from circuit board 1 because such optical module generates a large amount of heat.
Also, optical module 3 and circuit board 1 arranged in such a manner that optical module 3 and circuit board 1 are vertically spaced apart from each other, eliminate the need to reduce the size of circuit board 1 in order to secure a space for mounting optical module 3. Accordingly, a sufficient mounting area of circuit board 1 can be secured.
For enhancement in heat dissipation efficiency, it is preferable that each of base 7, cover 8 and plate 6 are made of a metal. In order to efficiently transfer heat from optical module 3 to the cover, as illustrated in
It is preferable that a plurality of pins 2 be provided in circuit board 1. In the present example, two pins 2 are diagonally provided at circuit board 1. Alternatively, three or more pins 2 may be provided at circuit board 1.
In the present exemplary embodiment, hole portion 5 is formed in a head portion of each fixing member 4 that fixes optical module 3 and plate 6 to each other. Each hole portion 5 faces a corresponding one of pins 2 provided at circuit board 1 and has a shape corresponding to the shape of pin 2. Pins 2 are provided coaxially with respective hole portions 5 and have a shape that is insertable into and removable from respective hole portions 5. Pins 2 and hole portions 5 may have any shape such as a circular column or a polygonal column As described later, pins 2 and hole portions 5 are used for placing optical module 3 on circuit board 1 during assembly of the optical transmitter/receiver apparatus.
Next, a method for manufacturing an optical transmitter/receiver apparatus will be described. First, as illustrated in
As illustrated in
As a result of pins 2 on circuit board 1 being fitted into respective hole portions 5 at head portions 21 of fixing members 4, optical module 3 is temporarily placed at a predetermined position on circuit board 1 with plate 6 directed upward. Consequently, optical module 3 is positioned in a direction parallel to a surface of circuit board 1.
As a result of fixing members 4 that fix optical module 3 and plate 6 to each other being used for placing optical module 3 on circuit board 1, the number of components can be reduced and a sufficient mounting area for optical module 3 can be secured. However, as necessary, members for fixing optical module 3 and plate 6 to each other may be provided separately from members for placing optical module 3 on circuit board 1.
Furthermore, optical module 3 and circuit board 1 are electrically connected. More specifically, connector 11 provided at flexible wiring board 18 is connected to connector 12 provided at circuit board 1, whereby optical module 3 is electrically connected to circuit board 1.
As illustrated in
If possible, the routing of optical fiber 14 may be performed before placing optical module 3 on circuit board 1.
Next, as illustrated in
As described above, optical fiber 14 is routed when both circuit board 1 and optical module 3 are placed on base 7, providing the advantage of being able to easily and correctly route optical fiber 14.
If optical fiber 14 is routed when at least one of circuit board 1 and optical module 3 is fixed to cover 8, optical fiber 14 extends from cover 8 over to base 7. Accordingly, when cover 8 is put on base 7, optical fiber 14 may be displaced or bent. If optical fiber 14 is bent with a predetermined bend radius or more, optical characteristics of optical fiber 14 may deteriorate or optical fiber 14 may be broken. According to the manufacturing method according to the present exemplary embodiment, optical fiber 14 can be routed on circuit board 1 fixed to base 7, enabling such problem to be avoided.
Since optical module 3 and circuit board 1 are electrically connected via a flexible wiring board, it is normally inconceivable that circuit board 1 would be fixed to the base 7 side on the one hand, and that optical module 3 would be fixed to the cover 8 side on the other hand. However, in the manufacturing method according to the present exemplary embodiment, optical module 3 is finally hoisted up a bit to cover 8 side and fixed to cover 8. Consequently, a structure in which circuit board 1 is fixed to the base 7 side and optical module 3 is fixed to the cover 8 side can easily be provided.
The present application is filed claiming the priority of Japanese Paten Application No. 2011-202227 filed on Sep. 15, 2011, the entire disclosure of which is hereby incorporated by reference.
Although an exemplary embodiment of the present invention has been presented and described in detail above, it should be understood that the present invention is not limited to the above exemplary embodiment and various alterations and modifications are possible without departing from the spirit.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-202227 | Sep 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/073643 | 9/14/2012 | WO | 00 | 2/26/2014 |
