JPH1093208A - Circuit board for optical communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit board for optical communication which enables reduction in cost, while obtaining a sufficient radiation effect with respect to a heating component. SOLUTION: This circuit board for optical communication includes a wiring board 1 which has an aperture portion 3, penetrating the wiring board 1 in the thickness direction thereof and which has electronic components 11, including a heating electronic component 14 mounted on the surface thereof, a heat sink 2 which is fixed on the back side of the wiring board 1 and closes the aperture portion 3 and which has an optical component 12 mounted on the surface thereof, and a metal cover 4 fixed to cover the surfaces of the wiring board 1 and the heat sink 2. The heating electronic component 14 and the metal cover 4 are thermally coupled with each other. The heating electronic component 14 may be mounted on the inner surface of the metal cover 4, in this case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board for optical communication (hereinafter, referred to as a circuit board) used when configuring an optical communication apparatus after mounting electronic parts and optical parts. The present invention relates to the structure of the circuit board.

[0002]

2. Description of the Related Art Hitherto, an optical fiber amplifier has been known as an example of an optical communication device. Among such optical fiber amplifiers, various types of electronic components have been simplified as shown in FIG. 11 and an optical component 12 are mounted on the same surface of a single wiring board 13. In this case, the electronic components 11 include exothermic electronic components 14 such as a laser driving transistor, a Peltier cooling element driving transistor, a current limiting resistor, and a current detecting resistor. Contains a laser 15 having a large heat-generating effect. Therefore, it is necessary to execute a structural design in consideration of heat radiation measures.
As a countermeasure, it is common to use a wiring board 13 made of a metal base, that is, a metal such as aluminum or copper. Reference numeral 16 in the figure denotes a metal cover disposed so as to surround the surface of the wiring board 13, and the metal cover 16 is used for the electronic component 11 and the optical component 1.
2 is provided for protection.

[0003]

However, the use of the metal-based wiring board 13 in the construction of the optical fiber amplifier according to the prior art is more costly than using a normal circuit board made of glass epoxy or the like. Not only is it inevitable to be high, but also a sufficient heat radiation effect as long as the heat-generating electronic component 14 and the laser 15 are mounted on the same wiring board 13 irrespective of the metal-based wiring board 13. Was not obtained. That is, in this case, since the heat conductivity of the metal-based wiring board 13 is too good, the heat from the heat-generating electronic component 14 is dissipated by the laser 15.
And the heat radiation of the laser 15 is hindered.

As the circuit scale of the optical fiber amplifier increases, the number of electronic components 11 and optical components 12 mounted thereon increases, and it is necessary to use a double-sided wiring board with a through-hole processing. In addition, there has been an inevitable problem that the cost required for the metal-based wiring board 13 is unavoidably increased.

SUMMARY OF THE INVENTION The present invention has been made in view of these disadvantages, and has as its object to provide a circuit board having a structure capable of achieving a cost reduction while obtaining a sufficient heat radiation effect for heat-generating components. I have.

[0006]

According to a first aspect of the present invention, there is provided a circuit board having an opening penetrating along a thickness direction, on which electronic components including heat-generating electronic components are mounted. It has a wiring board, a heat dissipation board on which the optical components are mounted on the surface by closing the opening of the wiring board, and a metal cover arranged around the surface of the wiring board and the heat dissipation board. The electronic component and the metal cover are thermally coupled to each other. In the circuit board according to the second aspect, a metal block protruding toward the heat-generating electronic component is disposed at a predetermined position on the inner surface of the metal cover facing the mounting position of the heat-generating electronic component. An elastic member having heat conductivity and insulating properties is interposed between the block body and the heat-generating electronic component, while the circuit board according to claim 3 is a mounting position for the heat-generating electronic component. A cut-and-raised piece protruding toward the heat-generating electronic component is formed at a predetermined position of the metal cover facing the heat-generating electronic component, and an elastic member having heat conductivity and insulation between the cut-and-raised piece and the heat-generating electronic component. Is interposed.

According to a fourth aspect of the present invention, there is provided a circuit board having an opening penetrating along a thickness direction, and a wiring board on which only electronic components other than heat-generating electronic components are mounted. A heat dissipating board having an optical component mounted on the surface by closing the opening of the wiring board, and a metal cover disposed on the surface of the wiring board and the heat dissipating board to form heat-generating electronic components. Is mounted on the inner surface of the metal cover. Furthermore, the circuit board according to claim 5 is characterized in that the outer peripheral surfaces of the heat dissipation board and the metal cover are each colored black.

[0008]

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

FIG. 1 is an assembled perspective view schematically showing a circuit board according to the present embodiment, and FIG. 2 is a side sectional view thereof.
FIGS. 3 to 5 are side sectional views showing circuit boards according to first to third modifications. 1 to 5, the same components and parts as those in FIG. 6 according to the conventional embodiment are denoted by the same reference numerals.

The circuit board according to the present embodiment is used when constructing an optical fiber amplifier which is an example of an optical communication device. As shown in FIG. A wiring board 1 made of glass epoxy or the like on which a large number of electronic components 11 including exothermic electronic components 14 such as an element driving transistor, a current limiting resistor, and a current detecting resistor are mounted on the surface; An optical component 12 including a laser 15 is provided on the surface. And the wiring board 1
Is formed with an opening 3 penetrating along a thickness direction of the wiring board. A heat dissipation board 2 made of a metal such as aluminum, brass, copper or the like or a ceramic is mounted on a wiring board by screwing or the like. 1 is fixed on the back surface and closes the opening 3. Here, the heat radiation board 2 is screwed to the wiring board 1, but the invention is not limited to such a configuration. For example, the shape and size of the heat radiation board 2 and the opening 3 And the heat radiation substrate 2 in the opening 3
It is also possible to press-fit.

Therefore, each of the optical components 12 mounted on the surface of the heat radiating substrate 2 passes through the opening 3 of the wiring substrate 1 and is exposed on the surface side of the wiring substrate 1. Electronic component 11 mounted on the surface of 1
Are connected to each other as necessary. Therefore,
The laser 15 included in the optical component 12 is
The heat generated by the laser 15 is radiated from the heat radiation substrate 2 to the outside. In FIG. 1, the opening 3 is formed substantially at the center of the wiring board 1. However, the position where the opening 3 is formed is not limited. Of course, the opening 3 may be formed at a position where the opening is opened.

The circuit board according to the present embodiment includes a metal cover 4 formed by bending a thin plate of aluminum, brass, copper, or the like, and the metal cover 4 is integrated with the wiring board 1 integrated with each other. And it is arranged so as to surround the surface of the heat radiation substrate 2. Then, as shown in FIG. 2, a predetermined position on the inner surface of the metal cover 4 opposite to the mounting position of the heat-generating electronic component 14 mounted on the surface of the wiring board 1 is made of aluminum, brass, copper, or the like. The metal block body 5 is fixed by screws or the like, and a heat conductive and insulating property is provided between the metal block body 5 and the heat generating electronic component 14 which are fixed in a state protruding toward the heat generating electronic component 14. , For example, an elastic member 6 such as a silicone gel having a low thermal resistance is interposed.

Therefore, the heat-generating electronic component 14 such as a laser driving transistor is directly thermally coupled to the metal cover 4 via the metal block 5 and the elastic member 6, so that the heat-generating electronic component 14 is formed. The heat generated by the component 14 is radiated from the metal cover 4 to the outside after passing through the metal block 5 and the elastic member 6. That is, in this embodiment, the heat generated by the heat-generating electronic component 14 is radiated through the metal cover 4, and the heat generated by the laser 15 as the optical component 12 is radiated from the heat-radiating substrate 2. Since the heat radiation path is separated into two, the heat-generating electronic component 1
4 and the laser 15 can secure more excellent heat radiation efficiency than the case where they are arranged on the same heat radiation substrate 2.

It should be noted that the heat-generating electronic component 14 in the present embodiment is not limited to the lead terminal type shown in FIG.
Then, as shown in FIG. 3 showing the first modification, when the heat-generating electronic component 14 is a surface mount type mounted in parallel on the surface of the wiring board 1, it has heat conductivity and insulation. After the elastic member 6 such as silicone gel is interposed, each of the heat-generating electronic components 14 and the metal block body 5 fixed on the inner surface of the metal cover 4 are thermally coupled to each other. In this case, since the elastic member 6 has an insulating property, it is unlikely that the external electrodes of the heat-generating electronic components 14 are electrically connected to each other via the metal block 5.

In the circuit board having the above-described configuration, the metal block 5 is disposed at a predetermined position on the inner surface of the metal cover 4, and the metal block 5 and the heat-generating electronic component 14 are interposed. Although the elastic member 6 having heat conductivity is interposed in the structure, the structure is not limited to such a structure, and a structure as shown in FIG. is there. That is, in this modified example, a predetermined position in the metal cover 4 that is arranged so as to surround the integrated wiring board 2 and the heat dissipation board 2,
That is, the cut-and-raised piece 4a is provided at a predetermined position of the metal cover 4 opposite to the mounting position of the heat-generating electronic component 14 mounted on the surface of the wiring board 1, and the cut-and-raised piece 4a is provided. Are bent so as to protrude toward the heat-generating electronic component 14.

The bent and raised piece 4a
An elastic member 6 having heat conductivity and insulation, such as silicone gel, is interposed between the heat-generating electronic component 14 and the heat-generating electronic component 14. Therefore, the cut-and-raised piece 4a provided on the metal cover 4 and the heat-generating electronic component 14 are thermally coupled to each other, and the heat generated in the heat-generating electronic component 14 such as a transistor for driving a laser is cut off by the cut-and-raised piece 4a Member 6
After passing through, it is radiated from the metal cover 4 to the outside. Therefore, when the configuration of the modified example shown in FIG. 4 is adopted, the same result as in the case of using the metal block body 5 is obtained.

Further, in the embodiment and the first and second modifications, all of the electronic components 11 including the heat-generating electronic component 14 are mounted on the surface of the wiring board 1, and the heat-generating electronic component 14 and the metal cover are mounted. 4 are thermally coupled to each other, but it is also possible to adopt a configuration as shown in FIG. 5 which is a third modification. That is, the circuit board according to the third modification has the opening 3 penetrating along the thickness direction, and only the general electronic component 11 excluding the heat-generating electronic component 14 is mounted on the surface. A wiring board 1, a heat dissipation board 2 on which an optical component 12 including a laser 15 is mounted on the surface by closing the opening 3 of the wiring board 1, and a surface of the integrated wiring board 1 and the heat dissipation board 2 And a metal cover 4 arranged so as to surround the upper part. At this time, the heat-generating electronic component 14 is mounted on the inner surface of the metal cover 4 using the hanging type support 7. I have.

That is, the exothermic electronic component 14 here is not of the surface mount type but of the lead terminal type.
4a is bent toward the wiring board 1 and is connected to an electrode pattern (not shown) formed on the surface of the wiring board 1. Therefore, the heat-generating electronic component 14 such as a laser driving transistor is directly thermally coupled to the metal cover 4, and the heat generated in the heat-generating electronic component 14 is radiated from the metal cover 4 to the outside. I will be made. In this case, as in the case of the embodiment and the first and second modified examples, since the heat generated by the laser 15 as the optical component 12 is radiated from the heat radiation substrate 2, two Since the heat radiation path exists, excellent heat radiation efficiency can be secured.

Further, when the heat dissipation board 2 and the metal cover 4 in the present embodiment are made of aluminum, so-called black alumite treatment is performed, and when the heat dissipation board 2 and the metal cover 4 are made of another metal or ceramic, they are painted black. It is preferable that the outer peripheral surface of each of the heat radiating substrate 2 and the metal cover 4 is colored black. If the outer peripheral surfaces are colored, the heat radiation efficiency of the heat radiating substrate 2 and the metal cover 4 is increased, and the heat radiating properties of these are improved. Will be improved. In the above description, it is assumed that the circuit board according to the present embodiment is used when configuring an optical fiber amplifier. Of course, the present invention can be applied to communication devices.

[0020]

As described above, according to the circuit board of the present invention, the optical component is mounted on the heat dissipation board integrated with the wiring board, and the metal arranged around the wiring board and the heat dissipation board. Since the cover and the heat-generating electronic component mounted on the wiring board are thermally coupled to each other, it is possible to secure the heat-dissipation paths of the heat-generating electronic component and the optical component separately. Therefore, not only can a sufficient heat radiation effect for the heat-generating component be obtained, but also a wiring board made of an inexpensive material such as glass epoxy can be used, so that the cost can be significantly reduced.

Further, even when the heat-generating electronic component is mounted on the inner surface of the metal cover, it is possible to secure the heat-dissipating paths for the heat-generating electronic component and the optical component separately, so that sufficient heat radiation to the heat-generating component is achieved. In addition to the effect, the effect that the cost can be reduced can be obtained.

[Brief description of the drawings]

FIG. 1 is an assembled perspective view showing a circuit board according to an embodiment in a simplified manner.

FIG. 2 is a side sectional view showing a main part thereof.

FIG. 3 is a side sectional view showing a main part of a circuit board according to a first modification.

FIG. 4 is a side sectional view showing a main part of a circuit board according to a second modification.

FIG. 5 is a side sectional view showing a main part of a circuit board according to a third modification.

FIG. 6 is an assembled perspective view schematically showing a circuit board according to a conventional form.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wiring board 2 Heat dissipation board 3 Opening 4 Metal cover 11 Electronic component 12 Optical component 13 Heat-generating electronic component

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor ▲ Minoru Yoshi ▼ 4-3-3 Ikejiri, Itami-shi, Hyogo Mitsubishi Cable Industries, Ltd. Itami Works (72) Inventor Mamoru Hashimoto 4-3-1 Ikejiri, Itami-shi, Hyogo (72) Inventor Takashi Okuyama 4-3 Ikejiri, Itami-shi, Hyogo Prefecture Mitsubishi Electric Corporation (72) Inventor Masataka Nakazawa 3-2-1, Nishishinjuku, Shinjuku-ku, Tokyo No. Nippon Telegraph and Telephone Corporation (72) Inventor Eiichi Yamada 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (5)

[Claims] A wiring board on which electronic components including heat-generating electronic components are mounted on a surface of the wiring board; Comprises a heat dissipation board on which the optical components are mounted, and a metal cover disposed around the surface of the wiring board and the heat dissipation board.The heat-generating electronic component and the metal cover are thermally coupled to each other. Characteristic circuit board for optical communication. 2. The optical communication circuit board according to claim 1, wherein a metal protruding toward the heat-generating electronic component is provided at a predetermined position on an inner surface of the metal cover facing the mounting position of the heat-generating electronic component. An optical communication circuit board, wherein a block body is arranged, and an elastic member having heat conductivity and insulation is interposed between the metal block body and the heat-generating electronic component. 3. The optical communication circuit board according to claim 1, wherein a cut-and-raised piece protruding toward the heat-generating electronic component is provided at a predetermined position of the metal cover facing the mounting position of the heat-generating electronic component. An optical communication circuit board, wherein an elastic member having heat conductivity and insulation is interposed between the cut and raised piece and the heat-generating electronic component. 4. A wiring board having an opening penetrating along the thickness direction and having on its surface only electronic components excluding heat-generating electronic components, and an opening on the wiring board closed to close the opening. Has a heat dissipation board on which optical components are mounted, and a metal cover arranged around the surface of the wiring board and the heat dissipation board, and the heat-generating electronic component is mounted on the inner surface of the metal cover. An optical communication circuit board, comprising: 5. The optical communication circuit board according to claim 1, wherein each of the heat dissipation board and the metal cover has an outer peripheral surface colored black. Circuit board.