JP3969376B2 - Optical communication equipment - Google Patents

Description

  The present invention relates to an optical communication device, and more particularly to a method for housing an optical module in a communication device.

Communication devices equipped with optical modules for optical input / output are known. In such a communication device, the optical module is fixed to a package or a substrate by screwing (see, for example, Patent Document 1 and Patent Document 2). At the time of this screwing, the optical axis shift and distortion of the optical module occur due to the stress caused by tightening. Therefore, in the technique of Patent Document 1, the flange portion of the butterfly type optical module has a smaller longitudinal elastic modulus than that of the main body, that is, a member that is easily deformed, so that the stress at the time of screwing is absorbed by the flange portion. This stress is prevented from reaching the optical module body. Further, in the technique of Patent Document 2, an optical module is sandwiched and fixed by a fixing member to prevent occurrence of optical axis deviation.
JP-A-6-82659 (paragraphs 0011 to 0013, FIGS. 1 and 2) JP 2001-284699 A (paragraphs 0011 to 0029, FIGS. 1 to 4)

  However, in any technique, when these optical modules are to be accommodated in a casing together with a substrate on which an electric circuit for signal processing is mounted, the optical module is fixed to the substrate or is independent of the substrate in the casing. Need to be fixed. In these cases, the positional relationship between the optical module and the substrate may fluctuate due to the stress caused by tightening the screws, and the stress may concentrate on the electrical connection portion between the optical module and the substrate. Furthermore, when the communication device is used in an environment with a temperature change, stress may concentrate on the electrical connection portion due to the difference in the linear expansion coefficient of each component. In addition, the heat dissipation characteristics from the optical module may fluctuate due to the deformation, which may change the input / output characteristics of the optical module.

  High-density mounting is required as optical data links become more functional. However, when using screws, it is necessary to secure the space for the screw itself and the space for inserting the screwdriver when fixing the screw. It was an obstacle. In addition, since the work time required to fix the screw is added to the product cost, improvement has been required from the viewpoint of cost reduction.

  Therefore, the present invention aims to provide a communication device using a butterfly optical module that avoids stress concentration on the electrical connection portion between the optical module and the substrate, exhibits stable characteristics, and is easy to assemble. And

In order to solve the above problems, a communication device according to the present invention is an optical communication device in which a butterfly-type optical module is accommodated in a housing together with a substrate. The housing is configured to engage an upper housing and a lower housing. The optical module is electrically and mechanically connected to the substrate by lead pins, the optical module is inserted into a notch provided on the substrate, and the optical module is sandwiched between the upper and lower housings Are fixed to each inner wall of the upper and lower housings so as to be able to conduct heat, a silicon sheet is sandwiched between at least one of the upper and lower housings and the optical module, and a copper foam sheet is interposed between the other of the upper and lower housings and the optical module. It is characterized by being sandwiched .

  In the communication device according to the present invention, the optical module is electrically and mechanically connected to the substrate by the lead pins. And it is fixed and accommodated by being sandwiched between the upper casing and the lower casing to be engaged and fixed.

  If it does in this way, the clearance gap between an optical module and a housing | casing is filled with the arrange | positioned sheet | seat.

  The optical input / output unit of the optical module may have a pigtail structure. Further, the casing is preferably made of aluminum die cast.

  In the communication device according to the present invention, the optical module is sandwiched and fixed between the upper and lower casings, and is not fixed by screwing, so that deformation due to stress due to tightening does not occur, and stress concentration on the lead pin portion Can be avoided, and stable characteristics can be exhibited. Further, by eliminating the screwing of the optical module, the assembly process is simplified and the assembly is facilitated.

  Furthermore, by disposing an elastic sheet having good thermal conductivity between the optical module and the housing, heat dissipation from the optical module to the housing is improved, and stable characteristics are easily exhibited.

  By employing the pigtail structure, it is possible to avoid the generation of mechanical stress caused by the attachment / detachment of the input / output optical fiber. By making the casing made of aluminum die cast, the heat dissipation characteristics from the casing are improved.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same reference numerals are given to the same components in the drawings as much as possible, and duplicate descriptions are omitted.

  FIG. 1 is an exploded view showing an internal configuration of an embodiment of a communication device according to the present invention, and shows a state where a lower housing 5 described later is removed. The communication device 100 is housed in a casing composed of an upper casing 4 and a lower casing 5 by assembling a substrate 3, a transmitting module 1 that is an optical module, and a receiving module 2 that is also an optical module. ing. An electronic circuit is mounted on the substrate 3, and the transmission module 1 and the reception module 2 are electrically connected to corresponding electronic circuits on the substrate 3 by a plurality of lead pins 10 and 20, respectively, and mechanically Also connected to the board and fixed. The substrate 3 is screwed to the upper housing 4 with screws 7, and the upper housing 4 and the lower housing 5 are also fixed by screwing with screws 6 described later. The screw holes 41 corresponding to the screws 6 of the upper housing 4 are arranged so as to avoid the substrate 3, and the substrate 3 is placed in a state free from the tightening of the screws 6.

  FIG. 2 is a cross-sectional view of the communication device 100. Here, in order to simplify the description, only the transmission module 1 is described as an optical module, and the reception module 2 is omitted. The housing 8 is made of aluminum die cast and has a box-shaped structure in which two of the upper housing 4 and the lower housing 5 are combined. A substrate 3 on which the transmission module 1 is assembled is disposed in the space inside the housing 8.

  Here, in the transmission module 1, a Peltier element 13 and a base plate 14 are stacked on a bottom plate 12 made of a material having good thermal conductivity such as aluminum or copper, and a laser diode (LD) as a light emitting element is stacked thereon. ) 15 is arranged. On the base plate 14, in addition to the LD 15, a photodiode (PD) that is a light receiving element for monitoring, a drive circuit for the LD 15, a drive circuit for the Peltier element 13, and the like are mounted. These circuits are connected to external circuits by lead pins 10.

  FIG. 3 is a cross-sectional view of the light emitting module along the optical axis direction. A lens unit 16 that collects the emitted light and an output optical fiber 17 that guides the collected light are disposed on the emission optical path of the LD 15. Here, the optical fiber 17 is assembled to the transmission module 1 and has a so-called pigtail structure. A case 11 is placed and fixed on the bottom plate 12 on which the Peltier element 13 and the LD 15 are placed. The receiving module 2 has the same configuration.

  As shown in FIG. 2, the transmission module 1 is arranged such that the top plate surface 11 a of the case 11 is in contact with the inner wall surface of the lower housing 5. It is preferable to sandwich a sheet 9 such as a silicon sheet having good thermal conductivity between the top plate surface 11a and the inner wall surface of the lower housing 5. The sheet 9 is preferably a material having a thickness of about 0.5 to 1 mm and having elasticity. According to this configuration, the stress when the transmission module 1 is sandwiched between the upper housing 4 and the lower housing 5 can be absorbed by the sheet 9. You may apply | coat grease with favorable heat conductivity to both surfaces of the sheet | seat 9, ie, the surface which contacts each of the top-plate surface 11a and the inner wall surface of the lower housing | casing 5. FIG.

  On the other hand, the heat radiation surface 12 side of the transmission module 1 is in direct contact with the inner wall surface of the upper housing 4. Most of the heat radiation from the transmission module 1 is concentrated on the heat radiation surface 12. In order to maintain good heat dissipation characteristics, it is preferable that the heat dissipation surface 12 and the inner wall of the upper housing 4 are in direct contact with each other. Furthermore, it is effective in terms of heat dissipation to apply grease having good thermal conductivity on both sides. Moreover, when both surfaces are in direct contact and the transmission module 1 is sandwiched between the upper housing 4 and the lower housing 5, mechanical stress may be directly applied to the heat radiating surface 12. In order to avoid this, a sheet having a thickness of about 0.1 mm made of a material having good heat conductivity such as a copper foam sheet is sandwiched between the heat radiation surface 12 of the transmission module 1 and the inner wall of the upper housing 4. It is also effective.

  In the communication device 100, the transmission module 1 that is an optical module is not screwed, but is sandwiched and fixed between the upper housing 4 and the lower housing 5. Here, it is preferable that the arrangement positions on the horizontal plane of the transmission module 1 and the reception module 2 that are optical modules are arranged at positions that are substantially equidistant from the screwing positions of the upper and lower casings 4 and 5. By arranging in such a place, the distribution in the plane direction of the force in the height direction acting by sandwiching the optical module by screwing the upper and lower casings 4 and 5 becomes substantially uniform, and the fixing is ensured. can do. Furthermore, since the distribution of the force in the height direction in the planar direction becomes substantially uniform, the occurrence of twisting of the optical module can be suppressed, and consequently the shift of the optical axis can be suppressed.

  When the upper and lower casings 4 and 5 are made of a highly rigid material such as aluminum die cast, the optical module may be arranged at a position where the distance from the screwed portion is not uniform. However, when at least one of the upper and lower housings 4 and 5 is formed of an elastic material such as a resin, it is more preferable that the distance from the screwed portion is uniform. For example, when the housing structure shown in FIG. 1 is used, screw holes 41 may be added to locations A and B between the transmission module 1 and the reception module 2.

  Further, by sandwiching the optical module (transmitting module 1 and receiving module 2) between the upper and lower casings 4 and 5, a sufficient contact area for conducting heat between the optical module and the upper and lower casings 4 and 5 is secured. A sufficient heat dissipation path from the optical module is ensured. This is particularly effective in the transmission module 1 having the LD 15 that generates a large amount of heat. And, not only the Peltier element 13 → the bottom plate 12 → the upper housing 4 which is the main heat radiation path, but also the sub-heat radiation path of the case 11 → the sheet 9 → the lower housing 5 is formed, thereby improving the heat radiation efficiency from the optical module. Can be increased. The optical module is small, has a small temperature difference between the bottom surface 12a and the top plate surface 11a, and has a sufficient effect of heat radiation from the top plate surface 11a.

  Further, by not screwing the optical module, it is not necessary to arrange a screw hole in the vicinity of the optical module on the substrate 3. Therefore, a circuit and a wiring pattern can be arranged in the vicinity of the optical module, and high integration can be achieved. It is also possible to increase the number of components mounted on the substrate 3.

  Next, a method for manufacturing a communication device according to the present invention will be specifically described. 4 and 5 are explanatory views showing this manufacturing process. Here, a configuration without the receiving module 2 will be described.

  First, a transmission module 1 as shown in FIG. Then, the transmission module 1 is inserted into the mounting notch 30 of the substrate 3 (see FIG. 4B), and the lead pins 10 of the transmission module 1 are soldered to the corresponding wiring patterns of the substrate 3. The transmission module 1 is fixed to the substrate 3 electrically and mechanically. At this time, the solder joints between the lead pin 10 and the board 3 are joined so as to have sufficient strength against the mechanical load applied to both.

  Next, as shown in FIG. 5A, the substrate 3 to which the transmission module 1 is fixed is accommodated in the accommodating recess 42 of the upper casing 4, and the substrate 3 is fixed to the upper casing 4 with the screws 7. To do. At this time, the bottom surface 12a which is a heat radiating surface of the transmission module 1 is directed to the upper housing 4 side. The tightening torque of the screw 7 does not need to be large.

  Next, the lower housing 5 is placed on the upper housing 4. At this time, a sheet 9 coated with grease on both sides is arranged between the lower housing 5 and the transmission module 1. And the upper housing | casing 4 and the lower housing | casing 5 are fastened and fixed with the screw 6 (refer FIG.5 (b)). Thereby, the communication apparatus 100 of this embodiment is obtained.

  In this embodiment, the transmission module 1 itself is fixed by tightening the upper housing 4 and the lower housing in this way, and the transmission module 1 is tightened because a substantially equal force acts on both the upper and lower surfaces. Therefore, there is no occurrence of misalignment or warping of the bottom plate of the transmission module 1 itself. For this reason, it is possible to suppress the positional deviation of the optical axis, particularly the positional deviation between the LD 15 and the lens unit 16 inside the transmission module 1. For this reason, the stability of the light output is improved.

  The communication device according to the present invention is not limited to the above-described embodiment, and any communication device in which at least one of the reception module and the transmission module is accommodated in the housing together with the substrate is sufficient. In the above-described embodiment, the transmission module 1 has the heat radiating surface 12 in contact with the upper housing 4, but it is also possible to adopt a configuration in which the heat radiating surface 12 is in contact with the lower housing 5. In that case, the sheet 9 is disposed between the upper housing 4 and the transmission module 1.

  Furthermore, in the above-described embodiment, the upper housing 4 and the lower housing 5 are assembled with a plurality of screws, that is, the upper housing 4 and the lower housing 5 are pressed against each other with the screws, so that the transmission module 1 is Although the structure is sandwiched, the present invention is not limited to screwing. For example, other engagement structures such as hooks can be employed.

It is an exploded view which shows the internal structure of one Embodiment of the communication apparatus which concerns on this invention. It is sectional drawing of the communication apparatus of FIG. It is sectional drawing of the transmission module of the communication apparatus of FIG. It is explanatory drawing which shows the manufacturing process of the communication apparatus of FIG. It is explanatory drawing which shows the continuation of the manufacturing process of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transmission module, 2 ... Reception module, 3 ... Board | substrate, 4 ... Upper housing | casing, 5 ... Lower housing | casing, 6, 7 ... Screw, 8 ... Housing | casing, 9 ... Radiation sheet, 10 ... Lead pin, 11 ... Case, DESCRIPTION OF SYMBOLS 11a ... Top plate surface, 12 ... Bottom plate, 12a ... Bottom surface, 13 ... Peltier element, 14 ... Base plate, 16 ... Lens unit, 17 ... Optical fiber, 41 ... Hole, 42 ... Housing recessed part, 100 ... Communication apparatus.

Claims (1)

In an optical communication device that houses a butterfly-type optical module together with a substrate,
The housing has a configuration for engaging the upper housing and the lower housing,
The optical module is electrically and mechanically connected to the substrate by lead pins, the optical module is inserted into a notch provided in the substrate, and the optical module is sandwiched between the upper and lower casings. Are fixed to the inner walls of the upper and lower housings so as to be capable of conducting heat,
A silicon sheet is sandwiched between at least one of the upper and lower housings and the optical module,
A copper foam sheet is sandwiched between the other of the upper and lower housings and the optical module,
An optical communication device characterized by that.

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