JP2005093507A - Optical transmission module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical transmission module which is improved in heat dissipation efficiency and easily mounted with other electronic parts, such as an electronic connector and the like. <P>SOLUTION: The optical transmission module 1 is equipped with a first metal cabinet 4 which is provided with an open top and houses a heating optical element module 2 and an electronic circuit board 3 which are fixed to it, and a second metal cabinet 5 covering the open top of the first metal cabinet 4. The optical element module 2 is fixed to the first metal cabinet 4 through the intermediary of a heat transfer member 15, and a soft member 16 which has heat dissipation and abut the second metal cabinet 5 is arranged at the upper part of the heat transfer member 15. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical transmission module having a metal casing for fixing an optical element module and an electronic circuit board and having excellent heat dissipation characteristics.

  As shown in FIG. 6, a conventional optical transmission module 51 includes a laser module (optical element module) 52 using a semiconductor laser and a first metal housing 54 for fixing an electronic circuit board 53. And a second metal casing 55 covering the open portion of the first metal casing 54. On the electronic circuit board 53, a control circuit (not shown) for driving the laser module 52, an electrical connector 56 connected to an external mother board, and other electronic components 57 are mounted.

  The laser module 52 is formed with a flange 59 in which a screwing hole 58 is formed, and a plurality of lead pins 62 are provided on the side surface of the main body 61. The first metal housing 54 is provided with a screw hole (not shown for an electronic circuit board) 63 for fixing the laser module 52 and the electronic circuit board 53.

  In assembling the optical transmission module 51, first, the electronic circuit board 53 is fixed to the first metal housing 54 with screws 64. Thereafter, the screw 64 is passed through the screw fixing hole 58 of the laser module 52, and the screw 64 is inserted and screwed into the screw hole 63 of the first metal housing 54 to be fixed. Next, the lead pins 62 of the laser module 52 are soldered to the electronic circuit board 53, and other electronic components 57 are soldered to the electronic circuit board 53. Finally, the second metal casing 55 is fixed to the first metal casing 54 with screws.

  Here, since the wavelength and optical output characteristics of a semiconductor laser greatly depend on temperature, it is necessary to stabilize the temperature in applications that require high performance such as for wavelength division multiplexing transmission. Therefore, the laser module 52 is configured by mounting a laser chip and a temperature detection thermistor on a temperature control Peltier element. The Peltier element is a thermoelectric cooling element of a P-type / N-type semiconductor junction pair having cooling ability, and both surfaces of the element can be heated and cooled by passing a direct current. Switching between heating and cooling by changing the direction of the current.

  By controlling the Peltier element so that the temperature detected by the thermistor is always constant, the operating temperature of the semiconductor laser is always kept constant regardless of the external temperature.

Japanese Utility Model Publication No. 5-82093 JP 2001-251008 A

  Here, the heat generated from the laser module 52 is transmitted from the flange 59 to the first metal casing 54 and is finally radiated to the surrounding space. However, since the optical transmission module 51 is fixed to an external mother board and the thermal resistance on the printed board side used for the external mother board is large, there is a problem that the heat radiation efficiency is not good.

  Therefore, the laser module 52 may be fixed to the upper second metal casing 55 and radiated from the second metal casing 55. However, when the laser module 52 is fixed to the second metal housing 55, the mounting structure of the electrical connector 56 and other electronic components 57 is greatly limited due to the relationship with the electronic circuit board 53, and the mounting work is difficult. There was a problem of becoming.

  That is, the assembly of the optical transmission module 51 satisfies various conditions such as the heat radiation of the ICs and the reliability of the solder connection between the IC on the electronic circuit board 53 and the laser module 52 in addition to the heat radiation of the laser module 52. However, by fixing the laser module 52 to the second metal housing 55, the mounting structure for these requirements has been greatly restricted.

  Accordingly, the present invention has been devised to solve the above problems, and an object of the present invention is to provide an optical transmission module that can obtain high heat dissipation efficiency and can easily mount other electronic components such as an electronic connector. There is.

  In order to achieve the above object, the present invention covers a first metal casing that is open at the top and fixes a heat-generating optical element module and an electronic circuit board therein, and an open portion of the first metal casing. An optical transmission module comprising a second metal housing, wherein the optical element module is fixed to the first metal housing via a heat conductive member, and the second heat conductive member has heat dissipation and the second heat conductive member. A flexible member that comes into contact with the metal casing is provided.

  And what provided the heat conductive protrusion part which contact | abuts to the said flexible member in the surface at the side of the said optical element module of said 2nd metal housing | casing is preferable.

  Further, the heat conductive member is formed so that a fixing member such as a screw for fixing the optical element module to the first metal casing can be attached, and the fixing member is formed from the inside of the first metal casing. It is preferable that the optical element module is fixed to the first metal casing by being inserted and attached to a heat conductive member.

  Further, the heat transfer member is formed so that a fixing member such as a screw for fixing the optical element module to the first metal casing can be attached, and the fixing member is connected to the first metal casing from the outside. The optical element module may be configured to be inserted and attached to a heat conductive member and fixed to the first metal casing.

  The heat transfer member is integrally attached to the optical element module, and the flange portion of the optical element module and the heat transfer member are screws for fixing the optical element module to the first metal casing. What was formed so that fixing members, such as, could be attached, is preferable.

  Furthermore, it is preferable that the flexible member is made of heat radiating resin or heat radiating grease.

  According to the present invention, high heat dissipation efficiency can be obtained, and other electronic components such as an electronic connector can be easily mounted.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing a preferred embodiment of an optical transmission module according to the present invention, and FIG. 2 is a perspective view showing a lower surface of a second metal casing of FIG.

  The optical transmission module according to the present embodiment is used in a communication network or a high-speed router network in a metropolitan area, and enables long-distance transmission without a repeater or an optical amplifier.

  As shown in the figure, the optical transmission module 1 has a first metal housing 4 that is open at the top and fixes a laser module (optical element module) 2 and an electronic circuit board 3 therein. And a second metal casing 5 covering the open portion. On the electronic circuit board 3, a control circuit (not shown) for driving the laser module 2, an electrical connector 6 connected to an external mother board, and other electronic components 7 are mounted.

  In the laser module 2, a flange 9 having a screwing hole 8 into which a screw 21 or the like as a fixing member is inserted is formed at the lens / fiber assembly 10 side of the main body 11 and the opposite side. . A plurality of lead pins 12 are provided on the side surface of the main body 11 different from the surface on which the flange 9 is formed. The flange 9 is formed in the vicinity of the side part of the main body part 11.

  The bottom surface of the first metal housing 4 is provided with a screw hole (not shown for an electronic circuit board) 14 into which a screw 21 as a fixing member for fixing the laser module 2 and the electronic circuit board 3 is screwed. ing.

  By the way, in the optical transmission module 1 according to the present embodiment, the laser module 2 is fixed to the first metal housing 4 via the heat conductive member 15, and the flexible member 16 having heat dissipation is disposed on the heat conductive member 15. The heat conductive protrusion 17 which contacts the flexible member 16 is provided on the surface of the second metal casing 5 on the laser module 2 side.

  The heat transfer member 15 is composed of a metal spacer 18 made of a metal having high heat transfer, and is provided on the upper portion of the flange 9 on the opposite side of the lens / fiber assembly 10 of the laser module 2. The metal spacer 18 is formed in a rectangular shape in plan view equivalent to the flange 9, and screw fastening holes 22 into which screws 21 are inserted are formed near both ends thereof. This screwing hole 22 is formed concentrically and with the same diameter as the screwing hole 8 of the flange 9. Between the screw holes 22, projecting portions 23 projecting upward are formed. The protrusion 23 is formed so that its upper end surface is flat and has a height substantially equal to the upper end of the head of the screw 21.

  The heat radiating flexible member 16 is constituted by a heat radiating sheet 19 formed of heat radiating resin such as silicone rubber sheet or silicone rubber adhesive, or heat radiating grease such as silicone oil compound. The heat dissipating sheet 19 is formed slightly thicker than the space between the upper surface of the metal spacer 18 and the lower surface of the heat conductive protrusion 17 described later, and the unevenness of the upper portion of the screw 21 and the error in mechanical processing accuracy of each metal part are reduced. It absorbs and the adhesiveness with the metal spacer 18 and the heat conductive protrusion 17 is improved.

  The heat conductive protrusion 17 is composed of a heat conductive block body 24 formed of metal or a heat radiating resin, and is attached to a position above the metal spacer 18 of the second metal housing 5. The heat conductive protrusion 17 may be formed integrally with the second metal housing 5.

  In assembling the optical transmission module 1 having the above configuration, first, the electronic circuit board 3 is fixed to the first metal casing 4 with the screws 21. Thereafter, the metal spacer 18 is placed on the flange 9 of the laser module 2 and the laser module 2 is set at the mounting position on the first metal housing 4. Then, the screw 21 is passed through the screw fixing holes 22 and 8 from above the laser module 2 (inside the first metal housing 4), and the screw 21 is inserted into the screw hole 14 of the first metal housing 4. The laser module 2 is fixed to the first metal housing 4 by screwing. Then, a heat dissipation sheet 19 is attached on the metal spacer 18.

  Next, the lead pins 12 of the laser module 2 are soldered to the electronic circuit board 3 and other electronic components 7 are soldered to the electronic circuit board 3. Finally, the second metal casing 5 is screwed and fixed to the first metal casing 4 to complete the assembly.

  At this time, the heat transfer protrusion 17 provided on the second metal housing 5 abuts on the heat dissipation sheet 19, and the laser module 2 passes through the screw 21, the metal spacer 18, the heat dissipation sheet 19, and the heat transfer protrusion 17. Then, it is connected (thermally coupled) to the second metal housing 5 so that heat can be transferred. Since the screw 21, the metal spacer 18, the heat dissipation sheet 19, and the heat transfer protrusion 17 each have high heat transfer efficiency and can suppress heat resistance to a low level, the heat generated from the laser module 2 is efficiently transferred to the second metal housing 5. Can communicate. Since the upper surface of the second metal casing 5 has a large area and is in contact with air, heat can be radiated from a wide range of surfaces to the surrounding space. Therefore, the heat dissipation efficiency is very high, and the temperature rise of the laser module 2 can be reliably prevented.

  In the above configuration, the metal spacer 18 and the like are provided in the space conventionally used for fixing the screws to dissipate heat, so that the change of the electronic circuit board 3 and the change of the layout of the electrical connector 6 and other electronic components 7 are performed. There is no need to do.

  Furthermore, since only the metal spacer 18 (heat transfer member 15), the heat radiation sheet 19 (flexible member 16), and the block body 24 (heat transfer protrusion 17) need to be added, there is almost no increase in cost.

  Further, according to the above configuration, since the laser module 2 is fixed to the lower first metal casing 4, the lead pins 12 can be easily soldered. In addition, the mounting structure of other electronic components 7 is not greatly limited, and the mounting work is not difficult. That is, a flexible mounting structure can be employed for the electronic circuit board 4. Therefore, heat radiation of ICs other than the laser module 2, ensuring high frequency electrical characteristics between the IC on the electronic circuit board 3 and the laser module 2, and reliability of solder connection between the lead pins 12 of the laser module 2 and the electronic circuit board 3 are ensured. Various conditions such as securing can be easily satisfied.

  In the present embodiment, the metal spacer 18 is provided only on one flange 9, but it may be provided on the flange 9 on the lens / fiber assembly 10 side. In this case, the metal spacer 18 is divided and provided on both sides of the lens / fiber assembly 10, and a heat radiating sheet and a heat conductive protrusion are provided on the upper part.

  Further, the fixing member is not limited to the screw 21 and may be another object such as a pin.

  3 is a perspective view showing another preferred embodiment of the optical transmission module according to the present invention, FIG. 4 is a perspective view showing the lower surface of the second metal casing of FIG. 3, and FIG. 5 is an optical diagram of FIG. It is the perspective view which showed the element module and the heat conductive member.

  The optical transmission module 31 is different from the optical transmission module 1 in the structure of the metal spacer 32 as the heat transfer member 15. The metal spacer 32 of the present embodiment is formed in a plane U shape extending from the flange 9 on the lens / fiber assembly 10 side of the laser module 2 to the flange 9 on the opposite side. The laser module 2 is fixed integrally so as to sandwich the laser module 2. Both ends of the metal spacer 32 extend to the screw holes 8 of the flanges 9, and screw holes 33 are formed at positions corresponding to the screw holes 8 (thread tapped).

  A heat radiating sheet 19 is provided on the upper portion of the flange 9 out of the upper portion of the metal spacer 32. A heat dissipation sheet 19 having a rectangular shape in plan view similar to that shown in FIG. 1 is provided on the flange 9 on the opposite side of the lens / fiber assembly 10, and the lens / fiber assembly is provided on the flange 9 on the lens / fiber assembly 10 side. 10 is provided on both sides of the heat dissipation sheet 19.

  A heat conductive protrusion 17 having the same shape as the heat radiating sheet 19 is provided on the lower surface of the second metal casing 5 above the heat radiating sheet 19.

  Other configurations are the same as those of the optical transmission module 1 shown in FIG.

  When assembling the optical transmission module 31 having the above configuration, the electronic circuit board 3 is first fixed to the first metal housing 4 with the screws 21 as in the above embodiment. Thereafter, the metal spacer 32 is fixed to the laser module 2 with an adhesive or the like, and the laser module 2 is set at the mounting position on the first metal housing 4. Then, a screw 21 is inserted from below the first metal housing 4 (outside the first metal housing 4), and the screw 21 is inserted into the screw hole 14 of the first metal housing 4 and the screw hole 33 of the metal spacer 32. Then, the laser module 2 is fixed to the first metal housing 4. Then, each heat radiation sheet 19 is attached on the metal spacer 32.

  Next, the lead pins 12 of the laser module 2 are soldered to the electronic circuit board 3 and other electronic components 7 are soldered to the electronic circuit board 3. Finally, the second metal casing 5 is screwed and fixed to the first metal casing 4 to complete the assembly.

  According to this, the same effect as the optical transmission module 1 of FIG. 1 mentioned above can be obtained. Furthermore, according to the above configuration, even if the plate thickness of the first metal casing 4 is thin, the screw hole 33 can be lengthened by the thickness of the metal spacer 32, so that the laser module 2 and the first metal casing 4 Fixed strength can be secured. However, in view of fixing the optical transmission module to another substrate or the like, the optical transmission module 1 of FIG. 1 in which the lower surface of the first metal housing 4 is formed flush with the other is superior.

  In the present embodiment, the heat conductive protrusion 17 of the second metal housing 5 is provided on the upper portion of the heat radiating sheet 19, but the thickness of the heat radiating sheet 19 is changed to the lower surface of the second metal housing 5. The heat dissipation sheet 19 may be brought into direct contact with the second metal casing 5 by increasing the thickness until it reaches the first metal casing 5. In this case, the heat conductive protrusion 17 need not be provided.

It is the perspective view which showed suitable embodiment of the optical transmission module which concerns on this invention. It is the perspective view which showed the lower surface of the 2nd metal housing | casing of FIG. It is the perspective view which showed other suitable embodiment of the optical transmission module which concerns on this invention. It is the perspective view which showed the lower surface of the 2nd metal housing | casing of FIG. It is the perspective view which showed the optical element module and heat conductive member of FIG. It is the perspective view which showed the conventional optical transmission module.

Explanation of symbols

1 Optical transmission module 2 Laser module (optical element module)
3 Electronic Circuit Board 4 First Metal Housing 5 Second Metal Housing 9 Flange 15 Heat Transfer Member 16 Flexible Member 17 Heat Transfer Protrusion 21 Screw 31 Optical Transmission Module

Claims (6)

  An optical transmission module comprising: a first metal housing that has an open top and a heat-generating optical element module and an electronic circuit board therein; and a second metal housing that covers an open portion of the first metal housing. In the above, the optical element module is fixed to the first metal casing via a heat conductive member, and a flexible member that has heat dissipation and contacts the second metal casing is provided above the heat conductive member. An optical transmission module characterized by the above.   2. The optical transmission module according to claim 1, wherein a heat conductive protrusion that abuts against the flexible member is provided on a surface of the second metal casing on the optical element module side.   The heat transfer member is formed so that a fixing member such as a screw for fixing the optical element module to the first metal casing can be attached, and the fixing member is attached to the heat transfer from the inside of the first metal casing. The optical transmission module according to claim 1, wherein the optical transmission module is configured to be inserted into a member and attached to fix the optical element module to the first metal casing.   The heat transfer member is formed so that a fixing member such as a screw for fixing the optical element module to the first metal casing can be attached, and the fixing member is attached to the heat transfer from the outside of the first metal casing. The optical transmission module according to claim 1, wherein the optical transmission module is configured to be inserted into a member and attached to fix the optical element module to the first metal casing.   The heat transfer member is integrally attached to the optical element module, and the flange portion of the optical element module and the heat transfer member are screws or the like for fixing the optical element module to the first metal casing. The optical transmission module according to claim 4, wherein the optical transmission module is configured to be attached with a fixing member. The optical transmission module according to any one of claims 1 to 5, wherein the flexible member is made of heat radiating resin or heat radiating grease.

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