JP2007019411A - Optical-to-electrical transducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress heat transfer amount from a component 24 for actuating a light emitting element toward the light emitting element 8. <P>SOLUTION: An optical transmitting module 10 provided with the light emitting element 8 which transduces electrical signals into optical signals and produces optical outputs is connected with a circuit board 2 by a terminal 18 for external connection of the light emitting element 8. In this state, the optical transmitting module 10 and the circuit board 2 are arranged and accomodated in a housing 6 formed of a thermo conductive material. The circuit board 2 is provided with heat radiation paths for the component 24 for actuating the light emitting element 8 composed of through-holes 28 which are formed from the surface of the board on which the component 24 is mounted for actuating the light emitting element 8, are extended toward the back side of the board and have openings in the back side of the circuit board 2 and thermo conductive materials formed inside the through-holes 28. A heat radiation member made of a thermo conductive material for radiating heat of the component 24 for actuating the light emitting component 8 which is transferred through the heat radiation paths toward the housing is interposed between the outlet forming region of the heat radiating paths and the part of the housing 6 opposed to the region. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical-electrical conversion device including an optical transmission module that converts an electrical signal into an optical signal and outputs the optical signal.

  FIG. 7 is a schematic cross-sectional view showing an example of main components of the photoelectric conversion device. The photoelectric conversion device 40 includes a circuit board 41, an LD module 42 that is an optical transmission module, an optical connector 43, an LD driver IC 44, an external connection terminal 45, and a housing 46. Has been.

  That is, the LD module 42 has a configuration in which a light emitting element (for example, a laser diode (LD)) 47 that converts an electrical signal into an optical signal and outputs the light is accommodated in the module case 48. In the LD module 42, a terminal 50 for external connection of the light emitting element protrudes from the inside of the module case 48 to the outside. The LD module 42 is arranged adjacent to the end face side of the circuit board 41, and the protruding portion of the terminal 50 outside the module case is joined to the circuit board 41 by a conductive joining material such as solder, so that the LD module 42 is connected to the circuit board 41. 41.

  The LD driver IC 44 is a light emitting element driving component having a circuit configuration for supplying an electric signal to the light emitting element 47, and the LD driver IC 44 is mounted on the circuit board 41. The circuit board 41 is formed with a wiring pattern for electrically connecting the connection portion of the terminal 50 of the LD module 42 and the LD driver IC 44. The light emitting element 47 inside the LD module 42 is connected to the terminal 50 and the circuit. It is electrically connected to the LD driver IC 44 through the wiring pattern of the substrate 41.

  The housing 46 accommodates and arranges both the circuit board 41 and the LD module 42 in a state where the circuit board 41 on which the LD driver IC 44 is formed and the LD module 42 are connected. It is comprised by. One end side of the external connection terminal 45 is connected to the circuit board 41, and the other end side protrudes outside the housing 46, and the external connection terminal 45 connects the circuit of the circuit board 41 in the housing 46 to the housing. 46 for electrical connection to the outside. The LD driver IC 44 converts the electrical signal for optical transmission supplied from the outside via the external connection terminal 45 into an electrical signal suitable for supplying to the light emitting element 47, and the converted electrical signal is converted into the electrical signal. Output toward the light emitting element 47. The light emitting element 47 converts the electric signal from the LD driver IC 44 into an optical signal and emits the optical signal.

  The optical connector 43 is connected to the LD module 42 for optically connecting an optical fiber (not shown) disposed inside the LD module 42 to an external optical fiber (not shown). It is. In other words, the optical connector 43 has a form that can be connected to an optical connector (not shown) provided at the tip of an optical fiber (not shown) inserted into the optical connector 43 from the outside. Is connected to the optical connector 43, and the external optical fiber and the optical fiber inside the LD module 42 are optically connected. The optical fiber inside the LD module 42 is arranged so that the optical signal output from the light emitting element 47 is incident, and the optical signal output from the light emitting element 47 is connected to the optical fiber inside the LD module 42. The optical signal is transmitted to the communication partner via the optical fiber connected to the optical connector 43.

JP 2003-234534 A Japanese Patent Laid-Open No. 10-247757

  By the way, the light emitting element 47 outputs an optical signal having a light intensity corresponding to the level of a current (hereinafter referred to as an LD driving current) of an electric signal to be supplied. For example, the light intensity of the optical signal has a relationship as indicated by a solid line La in the graph of FIG. However, since the relationship between the level of the LD drive current and the light intensity of the optical signal of the light emitting element 47 varies depending on the temperature as described below, the following problem occurs.

  That is, the change in the light intensity of the optical signal output from the light emitting element 47 with respect to the amount of fluctuation in the level of the LD driving current supplied to the light emitting element 47 (that is, the slope of the light output with respect to the LD driving current) is called slope efficiency This slope efficiency decreases as the ambient temperature of the light emitting element 47 increases. Specifically, for example, when the ambient temperature of the light emitting element 47 is Ta ° C., the relationship between the level of the LD drive current and the light intensity of the optical signal of the light emitting element 47 is shown by a solid line La in the graph of FIG. In contrast, when the ambient temperature of the light emitting element 47 reaches Tb ° C. higher than Ta ° C., the relationship between the level of the LD drive current and the light intensity of the optical signal of the light emitting element 47 is sloped. For example, the efficiency decreases and the relationship changes to that shown by the solid line Lb in the graph of FIG.

Thus, since the light emitting element 47 has temperature characteristics, for example, when the ambient temperature of the light emitting element 47 is Ta ° C., an electric signal (that is, the LD driving current of the LD driving current) as shown by the solid line A in FIG. when the electric signal) H level is a I _Ha is L level is I _La is supplied to the light emitting element 47, the level of the LD driving current, a solid line in FIG. 8 is the light intensity of the optical signal emitting element 47 Since the relationship shown by La is established, the light-emitting element 47 emits an optical signal as shown by the solid line α in FIG. 8 (that is, the H level of the light intensity is P _Ha and the L level is P _La . Optical signal). On the other hand, when the ambient temperature of the light emitting element 47 rises to Tb ° C. higher than Ta ° C., the electric signal (that is, the H level is I level) that is the same as when the ambient temperature of the light emitting element 47 is Ta ° C. _When an electric signal ( _Ha and L level is I _La ) is supplied to the light emitting element 47, the level of the LD drive current when the ambient temperature of the light emitting element 47 is Tb ° C. and the optical signal of the light emitting element 47 from the a relation such as shown by the solid line Lb in FIG. 8 is the light intensity, from the light emitting element 47, an optical signal as shown in chain line β in FIG. 8 (i.e., H level of the light intensity P _Hb And an optical signal whose L level is P _Lb ) is output. That is, the light intensity and amplitude of the optical signal output from the light emitting element 47 will fluctuate due to ambient temperature fluctuations.

  Therefore, the LD driver IC 44 normally has an auto power control function (APC) so that the level of the optical signal output from the light emitting element 47 does not change even if the ambient temperature of the light emitting element 47 changes. That is, for example, a monitoring light receiving element (for example, a monitoring photodiode (MPD)) 51 as shown in FIG. 9 is provided in the vicinity of the light emitting element 47. The monitoring light receiving element 51 has a configuration in which a part of the optical signal output from the light emitting element 47 is received and an electric signal having a current level corresponding to the received optical signal is output as a monitor signal. Based on the monitor signal supplied from the monitoring light receiving element 51, the LD driver IC 44 supplies the light intensity of the optical signal emitted from the light emitting element 47 to the light emitting element 47 so as to be stabilized in a predetermined state. The level of the electric signal (LD drive current level) is changed.

For example, even when the ambient temperature of the light emitting element 47 rises to Tb ° C. higher than Ta ° C., the LD outputs an optical signal in the same state as the optical signal when the ambient temperature of the light emitting element 47 is Ta ° C. The driver IC 44 supplies the light emitting element 47 with an electrical signal as indicated by a chain line B in FIG. 8 in which the H level of the LD drive current is I _Hb and the L level is I _Lb. As a result, the light signal as shown by the solid line α in FIG. 8 which is the same as when the ambient temperature of the light emitting element 47 is Ta ° C. is output from the light emitting element 47.

  By controlling the LD driving current of the LD driver IC 44 as described above, the optical signal of the light emitting element 47 is stabilized even if the ambient temperature of the light emitting element 47 fluctuates.

  In FIG. 9, a circuit 52 for preventing the disturbance of the waveform of the electric signal due to the parasitic inductance around the light emitting element 47 on the conduction path of the electric signal from the LD driver IC 44 to the light emitting element 47. Is installed.

  Incidentally, the LD driver IC 44 has a larger amount of heat generation during driving than other components such as a capacitor component and a resistor component. The heat generated from the LD driver IC 44 is transferred to the module case 48 of the LD module 42 via the circuit board 41 and the terminal 50 and raises the temperature inside the module case 48. Further, the heat of the LD driver IC 44 is directly transferred to the inside of the module case 48 via the circuit board 41 and the terminal 50 to increase the temperature inside the module case 48. That is, the ambient temperature of the light emitting element 47 increases.

  As described above, when the ambient temperature of the light emitting element 47 increases, the level of the LD driving current supplied from the LD driver IC 44 to the light emitting element 47 in order to stabilize the optical signal output from the light emitting element 47 as described above. Becomes larger. For this reason, the amount of heat generated from the LD driver IC 44 becomes larger, the amount of heat transferred from the LD driver IC 44 to the LD module 42 increases, and the ambient temperature of the light emitting element 47 further increases. Then, in order to prevent fluctuation of the optical signal of the light emitting element 47 due to the increase in ambient temperature, the level of the LD drive current of the LD driver IC 44 is further increased, and the amount of heat generated by the LD driver IC 44 is further increased. In addition, a vicious cycle of heat will occur.

  The present invention has been made to solve the above-mentioned problems, and its object is to prevent the occurrence of a vicious cycle of heat by suppressing the amount of heat transferred from the light emitting element driving component to the light emitting element side. An object of the present invention is to provide an opto-electric conversion device having a configuration that can be used.

In order to achieve the above object, the present invention has the following configuration as means for solving the above problems. That is, the present invention relates to an optical transmission module having a configuration in which a light emitting element that converts an electric signal into an optical signal and outputs the light is housed in a module case, and a light emitting element driving unit that supplies an electric signal to the light emitting element A circuit board on which components are mounted,
The optical transmission module is disposed adjacent to the end face side of the circuit board, and the optical transmission module is connected to the circuit board by a terminal for external connection of a light emitting element formed protruding from the module case of the optical transmission module. In the photoelectric conversion apparatus having a configuration in which both the transmission module and the circuit board are accommodated in a common casing made of a heat conductive material,
The circuit board has a configuration in which light emitting element driving components are mounted on the front surface side, and the circuit board is formed to extend from the mounting area of the light emitting element driving components on the front surface side to the back surface side. A through-hole having an opening on the back surface is formed, and a heat conductive material is provided inside the through-hole to dissipate heat from the light emitting element driving component from the front side of the circuit board to the back side. A heat dissipation path is configured,
Between the formation area of the heat outlet of the heat radiation path and the housing part facing the outlet formation area, the heat for the light emitting element driving component that has conducted the heat radiation path is radiated to the housing side. A heat dissipation member made of a heat conductive material is interposed.

The present invention also relates to an optical transmission module having a configuration in which a light emitting element that converts an electric signal into an optical signal and outputs the light is housed in a module case, and for driving the light emitting element that supplies the electric signal to the light emitting element. A circuit board on which components are mounted,
The optical transmission module is disposed adjacent to the end face side of the circuit board, and the optical transmission module is connected to the circuit board by a terminal for external connection of a light emitting element formed protruding from the module case of the optical transmission module. In the photoelectric conversion apparatus having a configuration in which both the transmission module and the circuit board are accommodated in a common casing made of a heat conductive material,
The circuit board is a multilayer board in which a plurality of layers are laminated, and a light emitting element driving component and a wiring pattern connected to the light emitting element driving component are provided on the surface of the circuit board. One layer inside the circuit board forms a ground layer for making a high-frequency signal conductive to the wiring pattern in a pair with the wiring pattern,
In the ground layer, a part of the ground pattern is removed in a portion located between the mounting area of the light emitting element driving component and the arrangement area of the optical transmission module, and the light emitting element driving component and the optical transmission module The heat resistance addition part which enlarges the thermal resistance in between is also provided.

  According to the present invention, the heat radiation path of the light emitting element driving component is formed in the circuit board by the through hole formed in the mounting region of the light emitting element driving component and the heat conductive material therein. Moreover, it was set as the structure by which the member for thermal radiation was interposed between the heat | fever exit area | region of the thermal radiation path of a circuit board, and the housing | casing part facing the said exit area | region. For this reason, a heat radiation path is formed from the light emitting element driving component to the housing through the heat radiation path of the circuit board and the heat radiation member between the circuit board and the housing. Since the entire process of the heat dissipation path is made of a heat conductive material, the heat resistance of the heat dissipation path is larger than the heat resistance of the heat dissipation path from the light emitting element driving component to the optical transmission module through the circuit board. It is small. As a result, the heat generated from the light-emitting element driving component is more transferred to the heat radiation path toward the housing through the heat radiation path and the heat radiation member than toward the optical transmission module through the circuit board. It will be radiated to the body side.

  For this reason, the amount of heat transferred from the light emitting element driving component to the optical transmission module can be suppressed, and the temperature increase of the optical transmission module can be suppressed. This prevents a problem that the ambient temperature of the light emitting element continues to rise due to the heat generation of the light emitting element driving component and the temperature characteristics of the light emitting element during the driving of the photoelectric conversion device. Can do.

  In addition, the inner wall surface portion of the housing that faces the exit formation region of the heat dissipation path of the circuit board has a configuration that is formed in a convex shape that protrudes inward toward the exit formation region of the heat dissipation path. Since the space between the outlet forming region of the heat sink and the housing portion facing the outlet forming region of the heat radiation path is narrowed, the light emitting element driving component reaches the housing through the heat radiation path of the circuit board and the heat radiation member. The length of the heat dissipation path up to is shortened, and the thermal resistance can be further reduced. Thereby, the heat generated from the light emitting element driving component is more easily transferred to the housing side via the heat dissipation path and the heat dissipation member of the circuit board. For this reason, the amount of heat transferred from the light emitting element driving component to the optical transmission module can be further reduced.

  Furthermore, by providing a configuration in which a heat dissipation member is interposed between the module case of the optical transmission module and the housing portion facing the module case, the heat of the module case of the optical transmission module is passed through the heat dissipation member. Heat can be efficiently radiated to the housing side. For this reason, the heat generated from the light emitting element can be radiated to the housing side via the module case and the heat radiating member. Thereby, the temperature rise of an optical transmission module can be suppressed. Also with such a configuration, an increase in the ambient temperature of the light emitting element can be suppressed, and occurrence of problems due to the increase in the ambient temperature of the light emitting element can be prevented.

  Further, the circuit board is formed as a multilayer board, and a part of the ground pattern of the part located between the mounting area of the light emitting element driving component and the arrangement area of the optical transmission module in the ground layer inside the circuit board By providing a configuration in which the heat resistance is removed (that is, a configuration in which a thermal resistance addition unit is provided), the thermal resistance between the light emitting element driving component and the optical transmission module can be increased. In other words, since the ground layer in the circuit board is made of metal, that is, a material having good thermal conductivity, most of the heat from the light emitting element driving component to the optical transmission module passes through the ground layer of the circuit board. Head to the optical transmitter module. By removing a part of the ground pattern located between the light emitting element driving component mounting area and the optical transmission module in the ground layer, the heat generated from the light emitting element driving component Since it avoids detouring and goes to the optical transmission module, the thermal resistance between the light emitting element driving component and the optical transmission module increases. For this reason, the amount of heat transferred from the light emitting element driving component to the optical transmission module can be suppressed. As a result, during the operation of the photoelectric conversion device, as described above, the problem is that the ambient temperature of the light emitting element continues to rise due to the heat generation of the light emitting element driving component and the temperature characteristics of the light emitting element. Can be prevented.

  In the case where the optical receiver module is provided, by providing the above-described configuration, it is possible to prevent the temperature of the optical receiver module from rising due to the heat generated from the light emitting element driving component. Can do. For this reason, when the light receiving element has temperature characteristics, it is possible to prevent a problem that the light receiving sensitivity of the light receiving element varies due to an increase in the ambient temperature of the light receiving element.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1A shows a schematic cross-sectional view of the photoelectric conversion apparatus of the first embodiment, and FIG. 1B shows an internal configuration example of the photoelectric conversion apparatus of FIG. Is shown by a schematic perspective view, and FIG. 1 (c) shows a schematic plan view of an internal configuration example of the photoelectric conversion device viewed from the upper side of FIG. 1 (b).

  The photoelectric conversion apparatus 1 according to the first embodiment includes a circuit board 2, an optical transceiver module (BiDi module) 3, an optical connector 4, an external connection terminal 5, and a housing 6. It is configured.

  The optical transmission / reception module 3 includes an optical transmission module 10 having a configuration in which a light emitting element (for example, a laser diode (LD)) 8 is accommodated in a module case 9 and a light receiving element (for example, an avalanche photodiode (APD)) 12. And an optical receiver module 14 having a configuration in which a preamplifier IC (not shown) is accommodated in the module case 13 and a connection member 16 that combines the optical transmitter module 10 and the optical receiver module 14. Has been.

  The light emitting element 8 converts an electrical signal into an optical signal and outputs it. The light receiving element 12 converts the received optical signal into an electric signal (current signal) and outputs the electric signal. The preamplifier IC converts the current signal output from the light receiving element 12 into a voltage signal and converts the voltage signal ( Electrical signal). In the first embodiment, an optical connector 4 is connected to the optical transmission / reception module 3, and one optical fiber is connected to the optical connector 4. That is, the optical transmission / reception module 3 is of a single core type, and an optical signal output from the light emitting element 8 (optical signal on the transmission side) and an optical signal supplied from the outside to the light receiving element 12 (on the reception side). The optical signal is transmitted through the same optical fiber (not shown). In the first embodiment, the wavelength of the optical signal on the transmission side is different from the wavelength of the optical signal on the reception side, and the optical signal on the reception side and the optical signal on the transmission side are different using the difference in wavelength. Is provided inside the connecting member 16 (see FIG. 1C).

  The optical transmission module 10 has an external connection terminal 18 protruding from the module case 9, and similarly, the optical reception module 14 has an external connection terminal 19 protruding from the module case 13. The circuit board 2 is provided with a notch 20 for arranging the module, and the optical transceiver module 3 is disposed adjacent to the end face side of the circuit board 2 at the position where the notch 20 of the circuit board 2 is formed. Has been. Then, the external connection terminal 18 of the optical transmission module 10 and the external connection terminal 19 of the optical reception module 14 are bonded and fixed to the circuit board 2 by a conductive bonding material such as solder, respectively. An optical transceiver module 3 is connected to the circuit board 2.

  On the circuit board 2, a transmission circuit 22 electrically connected to the light emitting element 8 via a terminal 18 and a receiving circuit 23 electrically connected to the light receiving element 12 via a preamplifier IC and a terminal 19 are separately provided. It is formed in the area.

  FIG. 2 shows a schematic cross-sectional view of the circuit board 2. In the first embodiment, the circuit board 2 is a multilayer board in which conductor pattern layers 26 (26a to 26d) and insulating layers 27 (27a to 27c) are alternately stacked. In the formation region of the transmission circuit 22 on the surface of the circuit board 2, an LD driver IC 24, which is a light emitting element driving component that supplies an electric signal to the light emitting element 8, is mounted (mounted). A post-amplifier IC (not shown) that amplifies the electric signal output from the preamplifier IC is mounted (mounted) in the formation region of the receiving circuit 23. Further, the conductor pattern layer 26d on the surface of the circuit board 2 has a wiring pattern for electrically connecting the LD driver IC 24 and the terminal 18 of the optical transmission module 10, a post-amplifier IC, and the optical reception module 14. A wiring pattern, a ground pattern, and the like for electrically connecting the terminal 19 are formed.

  The conductor pattern layer 26c inside the circuit board 2 is a ground layer. The ground layer 26c is paired with a wiring pattern between the LD driver IC 24 and the terminal 18 of the optical transmission module 10 and a wiring pattern between the post-amplifier IC and the terminal 19 of the optical reception module 14 and these wirings. A microstrip line is formed together with the pattern to conduct a high-frequency signal to the wiring pattern.

  Furthermore, the conductor pattern layer 26b inside the circuit board 2 is, for example, a power layer on which a wiring pattern for supplying power is formed, and the conductor pattern layer 26a on the back surface of the circuit board 2 includes, for example, A wiring pattern and a ground pattern are formed.

  In the first embodiment, the LD driver IC 24 is an IC component that employs a package having a ground pad on the bottom surface. In the mounting area of the LD driver IC 24, through holes 28 are formed extending from the front surface side to the back surface side of the circuit board 2 and having openings on both the front and back sides of the circuit board 2. In the first embodiment, a plurality of through holes 28 are formed, and all the through holes 28 are filled with a heat conductive material (for example, a metal material such as copper). A ground pattern 29 is formed in the mounting region of the LD driver IC 24 on the surface of the circuit board 2. The ground pattern 29 is connected to the heat conductive material inside all the through holes 28. The LD driver IC 24 is mounted on the circuit board 2 by bonding the ground pad on the bottom surface thereof directly to the ground pattern 29 with a conductive bonding material such as solder. On the back surface side of the circuit board 2, a ground pattern 30 connected to the heat conductive material inside all the through holes 28 is formed. The ground pattern 29, the through hole 28 and the heat conductive material in the through hole 28, and the ground pattern 30 constitute a heat radiation path for dissipating the heat of the LD driver IC 24 from the front surface side to the back surface side of the circuit board 2. Yes.

  The casing 6 is made of a heat conductive material such as metal having good thermal conductivity. The casing 6 includes a circuit board 2, an optical transceiver module 3, and an optical connector 4 as shown in FIG. It is to be housed. A terminal 5 for external connection projects from the circuit board 2 inside the housing 6 toward the outside of the housing 6. An electric signal is supplied from the outside to the LD driver IC 24 through the external connection terminal 5. In addition, an electrical signal output from the post-amplifier IC is output to the outside via the external connection terminal 5.

  In the first embodiment, since components for configuring a circuit are arranged on the back side of the circuit board 2, the back side of the circuit board 2 and the part of the housing 6 that faces the back side of the circuit board. Between the two, a gap for component placement is formed. Further, the inner wall surface portion 31 of the circuit board 2 facing the outlet formation region (the formation region of the ground pattern 30) of the heat dissipation path is formed in a convex shape protruding inward toward the outlet formation region of the heat dissipation path. . A heat dissipation sheet (for example, a silicon sheet), which is a heat dissipation member made of a heat conductive material, is formed between the convex protruding tip portion of the inner wall surface of the housing and the ground pattern 30 formed on the back surface of the circuit board 2. 32 is interposed. Further, a heat radiating sheet (for example, a silicon sheet) 33 that is a heat radiating member made of a heat conductive material is interposed between the module case 9 of the optical transmission module 10 and the housing portion facing the module case 9. ing. That is, in the first embodiment, a heat dissipation path from the LD driver IC 24 to the housing 6 via the heat dissipation path of the circuit board 2 and the heat dissipation sheet 32 is configured. In addition, a heat dissipation path from the module case 9 of the optical transmission module 10 to the housing 6 via the heat dissipation sheet 33 is configured.

  In the first embodiment, the optical connector 4 is fixed to the casing 6 by a pressing member 35 provided in the casing 6, and thus the optical transmission / reception module 3 connected to the optical connector 4 is also the casing. 6 is fixed. The holding member 35 is configured such that the optical connector 4 and the optical transmission / reception module 3 are fixed to the housing 6 in a state where the module case 9 of the optical transmission module 10 of the optical transmission / reception module 3 is pressed against the heat dissipation sheet 33. . Further, the circuit board 2 is screwed and fixed to a portion of the housing 6 facing the back side of the circuit board 2 with, for example, a metal screw. The screw is inserted from the front surface side to the back surface side of the circuit board 2 at the boundary position between the formation area of the transmission circuit 22 and the formation area of the reception circuit 23 in the circuit board 2, and the tip portion of the screw is formed in the housing 6. The screw holes are screwed together. By screwing the circuit board 2, the ground pattern 30 formed on the back surface of the circuit board 2 and the convex tip portion of the housing 6 are configured to press and hold the heat radiation sheet 32. In the first embodiment, the heat radiating sheets 32 and 33 are flexible. For this reason, when the module case 9 of the optical transmission module 10 is pressed against the heat radiating sheet 33, the surface portion of the heat radiating sheet 33 is deformed according to the shape of the module case 9. The degree of adhesion is increased. Further, the heat radiation sheet 32 is pressed and sandwiched between the ground pattern 30 and the convex tip portion of the housing 6, whereby the degree of adhesion between the ground pattern 30 and the heat radiation sheet 32 and the convex tip portion of the housing 6. And the adhesion degree of the heat radiating sheet 32 can be increased.

  As described above, the degree of adhesion between the module case 9 and the heat radiating sheet 33 is increased, so that the heat of the module case 9 of the optical transmission module 10 can be radiated to the housing 6 side through the heat radiating sheet 33 more efficiently. Can do. Further, by increasing the degree of adhesion between the ground pattern 30 and the housing 6 and the heat radiating sheet 32, the heat radiation efficiency for radiating heat from the LD driver IC 24 to the housing 6 side through the heat radiation path of the circuit board 2 and the heat radiating sheet 32 is improved. Can be improved.

  Furthermore, in the first embodiment, since the circuit board 2 is screwed and coupled to the metal housing 6 with a metal screw, the ground layer of the circuit board 2 is connected via the metal screw. It will be in the state electrically connected to the housing | casing 6 which functions as a ground. For this reason, when the noise of the electrical signal of the transmission circuit 22 is transmitted to the ground layer of the circuit board 2, the noise can be released to the housing 6 side through the metal screw. Thereby, the crosstalk that the noise of the electric signal of the transmission circuit 22 rides on the electric signal of the reception circuit 23 through the ground layer of the circuit board 2 can be suppressed. Note that the number of parts constituting the housing 6 is not limited. For example, the circuit board 2 is arranged on the back side of the circuit board 2 and supports the circuit board 2, and the circuit board 2 from the front side of the circuit board 2. A plurality of parts such as a cover that covers and may be integrated into a housing.

  The second embodiment will be described below. In the description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and duplicate descriptions of common portions are omitted.

  FIG. 3A shows a schematic cross-sectional view of the photoelectric conversion apparatus according to the second embodiment, and FIG. 3B schematically shows the characteristic components in the second embodiment. An enlarged cross-sectional view is shown.

  The photoelectric conversion apparatus 1 of the second embodiment is similar to the first embodiment in that the circuit board 2, the optical transceiver module 3, the optical connector 4, the external connection terminal 5, and the housing 6 are provided. In this second embodiment, the circuit portion immediately below the LD driver IC 24 as shown in the first embodiment is changed from the LD driver IC 24 on the surface side of the circuit board 2 in this second embodiment. A configuration for forming a heat radiation path that reaches the convex inner wall surface portion of the housing through the heat radiation sheet 32 is not provided. Further, the heat radiating sheet 33 for forming a heat radiating path is not provided between the optical transmission module 10 and the housing 6.

  In the second embodiment, as shown in FIG. 3B, the circuit board 2 has a multilayer structure in which conductor pattern layers 26 and insulating layers 27 are alternately stacked as in the first embodiment. It is a substrate. A wiring pattern for electrically connecting the LD driver IC 24 and the optical transmission module 10 of the optical transmission / reception module 3 is formed on the conductor pattern layer 26 d on the surface of the circuit board 2. The conductor pattern layer 26c inside the circuit board 2 forms a ground layer that forms a pair with the wiring pattern and conducts a high-frequency signal to the wiring pattern. A schematic plan view of the ground layer 26c is shown in FIG. In the ground layer 26 c, a ground removal portion 37 is formed by removing a part of the ground pattern in a portion located between the mounting region of the LD driver IC 24 and the region where the optical transmission module 10 is disposed. The ground extraction portion 37 is a thermal resistance adding portion that increases the thermal resistance between the LD driver IC 24 and the optical transmission module 10. The ground extraction portion (thermal resistance adding portion) 37 can suppress the amount of heat transferred from the LD driver IC 24 to the optical transmission module 10.

  Other configurations of the photoelectric conversion apparatus 1 of the second embodiment are the same as those of the first embodiment. In addition, since the ground removal portion 37 is provided at a position between the LD driver IC 24 and the optical transmission module 10, the LD driver IC 24 side is electrically connected by the wiring pattern between the LD driver IC 24 and the optical transmission module 10. Although there is a concern about impedance mismatch with the optical transmission module 10 side, the LD driver IC 24 and the optical transmission module 10 are connected to the LD driver IC in order to conduct a high-frequency signal for a communication speed of 1 Gbps or higher, for example. The distance between the IC 24 and the optical transmission module 10 cannot be increased for reasons such as to prevent signal degradation, and is as short as, for example, about 6 mm. There is almost no adverse effect.

  The third embodiment will be described below. In the description of the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and a duplicate description of the common portions is omitted.

  The photoelectric conversion apparatus 1 according to the third embodiment has both the characteristic components in the first embodiment and the specific components in the second embodiment. That is, in the third embodiment, for example, as shown in the schematic cross-sectional view of FIG. 1A, the circuit board 2 is formed to extend from the mounting region of the LD driver IC 24 on the front surface side to the back surface side. A through hole 28 having an opening is formed on the back surface of the circuit board, and the through hole 28 is filled with a heat conductive material. On the front surface side of the circuit board 2, a ground pattern 29 connected to the heat conductive material inside the through hole 28 is formed in the heat inlet formation region of the heat dissipation path, and heat dissipation on the back surface side of the circuit board 2. A ground pattern 30 connected to the heat conductive material inside the through hole 28 is also formed in the exit formation region of the path.

  An inner wall surface portion of the housing 6 facing the exit formation region of the heat dissipation path of the circuit board 2 has a convex shape protruding inward. A heat radiating sheet 32, which is a heat radiating member, is interposed between the projecting protruding tip portion of the housing 6 and the exit formation region of the heat radiating path of the circuit board 2. Further, a heat radiating sheet 33, which is a heat radiating member, is interposed between the module case 9 of the optical transmission module 10 and the housing portion facing the module case 9.

  Further, in the third embodiment as well, as shown in the schematic cross-sectional view of FIG. 4, the circuit board 2 is formed as a multilayer board as in the first and second embodiments. . A wiring pattern for electrically connecting the LD driver IC 24 and the optical transmission module 10 is formed on the surface of the circuit board 2. The conductor pattern layer 26c inside the circuit board 2 forms a ground layer for making a pair with the wiring pattern and conducting a high-frequency signal to the wiring pattern. In the third embodiment, the ground layer 26c has a ground pattern in a portion located between the mounting area of the LD driver IC 24 and the arrangement area of the optical transmission module 10, as in the second embodiment. A gland punched portion 37 is formed by removing a part of the gland. The ground extraction portion 37 is a thermal resistance adding portion that increases the thermal resistance between the LD driver IC 24 and the optical transmission module 10.

  Configurations other than those described above are the same as those in the first and second embodiments.

  In addition, this invention is not limited to the form of each 1st-3rd embodiment, Various embodiments can be taken. For example, in each of the first and third embodiments, the portion of the housing 6 that faces the exit formation region of the heat dissipation path of the circuit board 2 has a convex shape that protrudes toward the exit formation region of the heat dissipation path. However, for example, no component is mounted on the back side of the circuit board 2 or a very low-profile component is mounted, and the distance between the circuit board 2 and the housing 6 is very large. In other words, even if the portion of the housing 6 that faces the outlet formation region of the heat dissipation path is not formed to protrude inwardly, the heat outlet region of the heat dissipation path of the circuit board 2 and the housing 6 When the heat radiation sheet 32 can be interposed without a gap therebetween, the inner wall surface of the housing 6 does not have to be formed in a convex shape toward the heat outlet formation region of the heat radiation path.

  Further, in each of the second and third embodiments, the ground extraction portion 37, which is a thermal resistance adding portion formed in the ground layer 26c, has a rectangular shape, but has a shape other than the rectangular shape (for example, FIG. 5). Or a meander shape as shown in FIG.

  Furthermore, in each of the first to third embodiments, the optical transmission / reception module 3 in which the optical transmission module 10 and the optical reception module 14 are combined by the connection member 16 is provided. For example, the schematic diagram of FIG. As shown in the plan view, the optical transmitter module 10 and the optical receiver module 14 may be arranged separately and independently.

  Furthermore, in each of the second and third embodiments, the ground removal portion 37 is provided in the ground layer 26c of the circuit board 2. However, for example, the LD driver IC 24 is provided in another conductor pattern layer of the circuit board 2. When a ground pattern extending in the direction from the formation region toward the arrangement region of the optical transmission module 10 is formed, a ground extraction portion that functions as a thermal resistance adding portion is also formed on a part of the ground pattern. It may be formed.

  Furthermore, in each of the first to third embodiments, both the optical transmission module 10 and the optical reception module 14 are provided. For example, only the optical transmission module 10 is provided and the optical reception module 14 is provided. The present invention can also be applied to a photoelectric conversion device that is not provided.

It is a figure for demonstrating the photoelectric conversion apparatus of the example of 1st Embodiment. It is typical sectional drawing for demonstrating the structural example of the thermal radiation path provided in the circuit board in the example of 1st Embodiment. It is a figure for demonstrating the photoelectric conversion apparatus of the example of 2nd Embodiment. It is typical sectional drawing for demonstrating one example of the structural part of the circuit board characteristic in 3rd Embodiment. It is a model figure for demonstrating the other example of a ground extraction part formed in the ground layer of a circuit board. It is a typical top view for explaining other examples. It is typical sectional drawing for demonstrating one example of the photoelectric conversion apparatus provided with the optical transmission module. It is a graph for demonstrating the temperature characteristic of a laser diode. It is a figure for demonstrating the structural example for performing the temperature compensation of a laser diode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoelectric conversion apparatus 2 Circuit board 6 Case 8 Light emitting element 9, 13 Module case 10 Optical transmission module 12 Light receiving element 14 Optical receiving module 24 LD driver IC
28 Through-hole 32, 33 Heat dissipation sheet 37 Ground removal part

Claims (6)

An optical transmission module having a configuration in which a light emitting element that converts an electrical signal into an optical signal and outputs light is housed in a module case, and a light emitting element driving component that supplies the light signal to the light emitting element are mounted. A circuit board,
The optical transmission module is disposed adjacent to the end face side of the circuit board, and the optical transmission module is connected to the circuit board by a terminal for external connection of a light emitting element formed protruding from the module case of the optical transmission module. In the photoelectric conversion apparatus having a configuration in which both the transmission module and the circuit board are accommodated in a common casing made of a heat conductive material,
The circuit board has a configuration in which light emitting element driving components are mounted on the front surface side, and the circuit board is formed to extend from the mounting area of the light emitting element driving components on the front surface side to the back surface side. A through-hole having an opening on the back surface is formed, and a heat conductive material is provided inside the through-hole to dissipate heat from the light emitting element driving component from the front side of the circuit board to the back side. A heat dissipation path is configured,
Between the formation area of the heat outlet of the heat radiation path and the housing part facing the outlet formation area, the heat for the light emitting element driving component that has conducted the heat radiation path is radiated to the housing side. An optical-electrical conversion device comprising a heat dissipation member made of a heat conductive material. Between the back surface of the circuit board and the housing part facing the back surface of the circuit board, the back surface of the circuit board has a configuration in which a gap for arranging components for electric circuit configuration is provided,
The inner wall surface of the housing facing the heat radiation path outlet forming area on the back side of the circuit board is formed in a convex shape protruding inward toward the heat radiation path outlet forming area,
The heat dissipating member is interposed between a heat radiation path outlet forming region on the back surface of the circuit board and a convex protruding tip portion of the inner wall surface of the casing facing the heat radiation path outlet forming region. 1. The photoelectric conversion apparatus according to 1.   Between the module case of the optical transmission module and the housing part facing the module case, a heat radiating member made of a heat conductive material for dissipating the heat of the module case to the housing side is interposed. The photoelectric conversion apparatus according to claim 1 or 2, wherein The circuit board is a multilayer board in which a plurality of layers are laminated, and a light emitting element driving component and a wiring pattern connected to the light emitting element driving component are provided on the surface of the circuit board. One layer inside the circuit board forms a ground layer for making a high-frequency signal conductive to the wiring pattern in a pair with the wiring pattern,
In the ground layer, a part of the ground pattern is removed in a portion located between the mounting area of the light emitting element driving component and the arrangement area of the optical transmission module, and the light emitting element driving component and the optical transmission module 4. The photoelectric conversion apparatus according to claim 1, further comprising a thermal resistance adding unit that increases a thermal resistance between the two. An optical transmission module having a configuration in which a light emitting element that converts an electrical signal into an optical signal and outputs light is housed in a module case, and a light emitting element driving component that supplies the light signal to the light emitting element are mounted. A circuit board,
The optical transmission module is disposed adjacent to the end face side of the circuit board, and the optical transmission module is connected to the circuit board by a terminal for external connection of a light emitting element formed protruding from the module case of the optical transmission module. In the photoelectric conversion apparatus having a configuration in which both the transmission module and the circuit board are accommodated in a common casing made of a heat conductive material,
The circuit board is a multilayer board in which a plurality of layers are laminated, and a light emitting element driving component and a wiring pattern connected to the light emitting element driving component are provided on the surface of the circuit board. One layer inside the circuit board forms a ground layer for making a high-frequency signal conductive to the wiring pattern in a pair with the wiring pattern,
In the ground layer, a part of the ground pattern is removed in a portion located between the mounting area of the light emitting element driving component and the arrangement area of the optical transmission module, and the light emitting element driving component and the optical transmission module An opto-electrical conversion device, characterized in that a thermal resistance adding section for increasing the thermal resistance between the two is provided.   An optical receiving module having a configuration in which a light receiving element that converts a received optical signal into an electrical signal and outputs the same is accommodated in a module case is accommodated in a common housing together with the optical transmission module and the circuit board. The photoelectric conversion apparatus according to claim 1, further comprising a configuration.

Images