JP2002118384A - Electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic equipment having a high mounting density, excellent heat radiating characteristics and reliability at a low cost. SOLUTION: The electronic equipment comprises an electronic circuit board 32 having a heating first electronic component 31 mounted on its front surface and a case 33 for housing the board 32. The board 32 has a plurality of through holes 35 thermally connected to the component 31 directly under the component 31, and a ground pattern 38 thermally connected to the holes 35. The case 33 has a protrusion 42 thermally connected to the hole 35 contacted with the rear surface of the board 32 directly under the component 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic apparatus having a case containing an electronic circuit board on which heat-generating electronic components are mounted.

[0002]

2. Description of the Related Art In recent years, with the development of miniaturization and high integration technology of electronic parts, the miniaturization of electronic equipment mounted on an electronic circuit board typified by an optical transceiver has been rapidly progressing. An increase in the heat generation density accompanying the miniaturization of the mounted electronic equipment has begun to be regarded as a problem. Furthermore, due to the high integration of electronic components, the heat generation distribution in the electronic device mounted on the electronic circuit board tends to concentrate on a specific location, and it is expected that these trends will be further strengthened in the future. In view of further increase in heat generation density and concentration of heat distribution in the future due to downsizing of the electronic device mounted on the electronic circuit board, development of an electronic device mounted on the electronic circuit substrate having more excellent heat radiation characteristics has been demanded.

Conventionally, the heat generation density has increased as described above,
When radiating heat from electronic devices mounted on electronic circuit boards with concentrated heat generation, a ceramic substrate with excellent thermal conductivity and electrical characteristics is generally used for the substrate material, and the entire back surface of the substrate is bonded with an adhesive or the like. It was mounted in contact with the case.

As such a conventional electronic device mounted on an electronic circuit board, for example, there is an electronic device having a structure as shown in FIG. In FIG. 12, reference numeral 1 denotes a heat-generating component such as a heat-generating electronic component such as a power transistor. Reference numeral 2 denotes an electronic circuit board composed of a ceramic substrate on which the heat-generating component 1 is mounted. The upper part of the case 3 is opened to take the electronic circuit board 2 in and out. 4 is an adhesive for fixing the electronic circuit board to the case 3, and 5 is a cover for covering the opening of the case 3.

In the electronic device mounted on the electronic circuit board of the first conventional example, the heat generated by the heat-generating component 1 is diffused throughout the electronic circuit board 2 made of a ceramic substrate having excellent thermal conductivity. The diffused heat is transferred to the case 3 via the adhesive 4. The heat transmitted to the case 3 is radiated to the outside air by the case 3 serving as a radiator. In this case, by using a ceramic substrate having excellent thermal conductivity as the electronic circuit board 2, the heat generated by the heat-generating components is diffused throughout the board, and the diffused heat is applied to the back surface of the electronic circuit board 2 in contact with the case 3. Since the heat is radiated from the entire surface to the case 3 having the effect of the radiator, the heat is efficiently radiated.

FIG. 13 is a sectional view of a main part of a second conventional electronic apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 8-204070.
A through hole 23 for sending a signal from the semiconductor element 21 to the electronic circuit board 22 is wired in an electronic circuit board 22 on which the semiconductor element 21 is mounted, and a surface on which a specific semiconductor element 21 is mounted on the electronic circuit board 22. A flexible heat conductor 24 or an adhesive is in close contact with a surface different from the above, and a protrusion 25 of a metal housing wall 26 is connected to the heat conductor 24. In this case, much heat from the semiconductor element 21
The heat is diffused widely to the housing wall 26 via the heat conductor 24 and the projection 25, and the wide surface of the housing wall is used as a heat radiation surface, and high heat radiation performance to the semiconductor element 21 is obtained.

Further, a third conventional example, Japanese Patent Application Laid-Open No. 11-4
No. 0742 discloses that the lower surface of a module case is brought into contact with a metal portion formed on a motherboard, and the heat of the metal portion is transmitted to a ground or a power supply layer in the motherboard through a through hole to dissipate heat and to dissipate heat. The structure in which the heat radiation fin of the module is unnecessary is shown.

[0008]

However, in the electronic device mounted on the electronic circuit board according to the first conventional example configured as described above, the ceramic circuit board is used as the material of the electronic circuit board 2 and the electronic circuit board is used. Case 3 covers the entire back surface of substrate 2
Therefore, there is a problem that the mounting density is reduced because the mounting must be performed in contact with the semiconductor device. That is, when the heat-generating component 1 is mounted on a downsized electronic circuit board-mounted electronic device,
In general, as described above, a ceramic material having excellent thermal conductivity is used for the substrate material due to the need for heat dissipation, and the entire back surface of the electronic circuit board 2 is brought into contact with the case 3 for mounting. For this reason, usually, the electric and
Electronic components were not mounted. If electrical and electronic components are also mounted on the back surface of the electronic circuit board 2 with emphasis on the mounting density, the ceramic substrate must be floated from the case 3 and attached. It is conceivable that the ceramic substrate cannot withstand the use environment and cracks and the like occur on the ceramic substrate. in this way,
Conventionally, electric and electronic parts are mounted on the electronic circuit board 2
However, there is a problem that the component mounting density is reduced by half. In addition, since an expensive ceramic material having a component price must be used as the material of the electronic circuit board 2, there is a problem that the product price increases.

[0009] In a second conventional electronic device,
A large amount of heat from the semiconductor element 21 is widely diffused into the housing wall 26 via the heat conductor 24 and the projection 25, and although the heat dissipation performance to the semiconductor element 21 is improved, the semiconductor element 2
1, the heat released by heat conduction is limited to only the route released from the through hole 23, the heat conductor 24, the protrusion 25, and the housing wall 26 to the outside. Element 21 is small and through hole 23
When the region cannot be made large, there is a problem that improvement in the heat radiation performance of the semiconductor element 21 cannot be expected. The protruding portion 25 is formed by projecting a part of the housing wall 26 inward at a right angle, and includes a flat portion 25a and a vertical portion 25b. Of the heat generated in the semiconductor element 21,
The heat released by heat conduction passes through the vertical portion 25b, but there is also a problem that the vertical portion 25b has a small heat passage cross-sectional area and a large thermal resistance. In addition, since the size of the flat portion 25a of the projection 25 is larger than the size of the semiconductor element 21, there is also a problem that the area for mounting electronic components on the back surface of the electronic circuit board 22 is reduced accordingly.

In a third conventional example of electronic equipment,
The heat radiation by the heat conduction of the module of the electronic circuit package is limited only to the through hole, the ground or the power supply layer, and the route radiated from the motherboard to the outside. As in the second conventional example, the area of the through hole is increased. If not, there is a problem that improvement of the heat radiation performance of the module cannot be expected.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic device which is inexpensive, has a high mounting density, and has excellent heat radiation characteristics and reliability. I do.

[0012]

According to the present invention, there is provided an electronic apparatus comprising:
An electronic circuit board having a heat-generating first electronic component mounted on a surface thereof; and a case accommodating the electronic circuit board, wherein the electronic circuit board is provided with a first electronic component immediately below the first electronic component. A plurality of through-holes thermally connected to the electronic component, a ground pattern thermally connected to the through-hole, and the case includes the electronic circuit board immediately below the first electronic component. Has a protrusion abutting on the back surface portion of the substrate and thermally connected to the through hole.

In the electronic device of the present invention, a plurality of ground patterns are provided, and these ground patterns may have different shapes.

In the electronic device according to the present invention, at least one second electronic component having a smaller heat generation than the first electronic component is mounted on the back surface of the electronic circuit board, and the second electronic component has a protrusion. It may be arranged in a space between the case and the back surface of the surrounding electronic circuit board.

In the electronic device according to the present invention, the projection may be formed by pushing a part of the case inward.

In the electronic device of the present invention, the projection may have a solid structure.

In the electronic device according to the present invention, the projection may have a truncated pyramid shape including a flat portion and an inclined portion.

In the electronic device of the present invention, the flat portion of the projection may be provided with a through hole inside the flat portion, and may be provided with a first electronic component extending to the outside of the flat portion.

An electronic apparatus according to the present invention includes an electronic circuit board having a heat-generating first electronic component mounted on a surface thereof, and a case accommodating the electronic circuit board. Having a protrusion abutting on the back surface of the electronic circuit board directly below the electronic component and thermally connected to the electric circuit board, the protrusion having a truncated pyramid shape including a flat portion and an inclined portion. is there.

In the electronic device according to the present invention, the second electronic component may be mounted on the back surface of the electronic circuit board facing the inclined portion.

In the electronic device of the present invention, the through holes may be filled with heat radiation grease.

In the electronic device according to the present invention, a heat radiation grease or a heat radiation sheet may be interposed between the electronic circuit board and the flat portion of the case.

In the electronic device according to the present invention, the electronic circuit board may be fixed to the case by a fixing member, and the ground pattern may be thermally connected to the case via the fixing member.

In the electronic device according to the present invention, the electronic circuit board has a through hole for a fixing member thermally connected to a ground pattern, and the fixing member is provided in the through hole for the fixing member on the back surface of the electronic circuit board. It is a stepped pin having a small-diameter part inserted from the side to the front side and a large-diameter part abutting on the back surface of the electronic circuit board, and the electronic circuit board is fixed to the small-diameter part by soldering.

In the electronic device of the present invention, the case has an insertion hole into which the stepped pin is inserted, and the stepped pin is inserted into the insertion hole on the side opposite to the small-diameter portion, and is caulked and fixed. It may have a fixing part.

In the electronic device according to the present invention, the base material of the electronic circuit board may be made of BT resin.

In the electronic device according to the present invention, the first electronic component may be an electronic circuit component for transmitting a signal from a DC level to a high-frequency level with the optical semiconductor component.

In an electronic apparatus according to the present invention, an electronic device includes an electronic circuit board and a support member supporting the electronic circuit board, wherein a stepped pin is provided between the electronic circuit board and the support member. The stepped pin has a small-diameter portion that is inserted into the insertion hole formed in the electronic circuit board from the back surface side to the front surface side of the electronic circuit board, and a large-diameter portion that contacts the back surface of the electronic circuit board, The electronic circuit board is fixed to the small-diameter portion of the front-stage pin by solder.

In the electronic device of the present invention, the stepped pin is
The non-small-diameter portion may have a caulking fixing portion that is inserted into the insertion hole of the support member and is caulked and fixed.

In the electronic device according to the present invention, a space is formed between the electronic circuit board and the support member by the large-diameter portion of the stepped pin, so that both sides of the electronic component can be mounted on the electronic circuit board. It may be something.

An electronic apparatus according to the present invention includes an electronic circuit board, a case accommodating the electronic circuit board, and an optical semiconductor component fixed to the case. Are electrically connected by a film substrate.

In the electronic device of the present invention, an electronic circuit board having a plurality of through-holes on which a heat-generating electronic component is mounted and which is thermally connected to the heat-generating electronic component immediately below the heat-generating electronic component; A heat dissipating member that is in contact with the back surface portion of the electronic circuit board immediately below the heat-generating electronic component and that is thermally connected to the through hole; the electronic circuit board includes a signal pattern for the heat-generating electronic component; A groove or slit is formed between the plurality of through holes and the area where the plurality of through holes are formed.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In each embodiment, the same or equivalent members and portions will be denoted by the same reference numerals. Embodiment 1 FIG. FIG. 1 is a sectional view of a main part of an optical receiver which is an electronic apparatus according to Embodiment 1 of the present invention. First, the optical receiver will be briefly described based on the block diagram of FIG.
In the figure, reference numeral 81 denotes a PD (photodiode) which is an optical semiconductor component that receives an optical signal and converts it into an electric signal, and 82 denotes an optical fiber 1000 connected from the transmitting side to the module.
Is an optical module that condenses the second optical signal sent through the lens 500 and converts the received light by the PD 81 to output an electric signal. Reference numeral 83 denotes a preamplifier for amplifying an electric signal including a high-frequency signal output from the PD 81. Reference numeral 84 denotes a single electric signal (for example, a signal of 40 Gb / s) amplified by the preamplifier 83, and a plurality of electric signals. It is a data separation unit which is an optical semiconductor component for extracting (for example, 16 signals of 2.5 Gb / s). The plurality of reproduced electric signals are transmitted to external devices through signal lines.

Next, the configuration of an optical receiver as an electronic device will be described. The optical receiver includes an electronic circuit board 32,
Heat-generating first electronic component 31 such as a data separation unit 84 or a preamplifier 83 mounted on the surface.
And a plurality of second electronic components 34 mounted on the back surface of the electronic circuit board 32 and generating less heat than the first electronic components 31.
And the electronic circuit board 32, the first electronic component 31, and the second
And a case 33 accommodating the electronic component 34.
The electronic circuit board 32 includes a base material 36 made of BT resin.
A signal pattern 37 formed on the front and back surfaces and inside of the base material 36; a ground pattern 38 formed on the front surface and inside of the base material 36; Solder resist 39,
A plurality of through-holes 35 penetrating the base material 36 immediately below the first electronic component 31 and connected to a ground pattern 38 extending in the horizontal direction. A heat radiation grease 41 made of silicon grease interposed between a projection 32 of a case 33 to be described later; and a metal wiring having one end connected to the first electronic component 31 and the other end connected to the signal pattern 37. 40. The plurality of ground patterns 38 connected to the through-holes 35 have different shapes, and each diffuses the heat of the first electronic component 31 over the entire electronic circuit board 32 and releases the heat to the outside air. ing.

The aluminum case 33 has a projection 42 which is in contact with the back surface of the electronic circuit board 32 immediately below the first electronic component 31 via the heat radiation grease 41 and is thermally connected to the through hole 35. Is formed. Protrusion 42
Is formed in a truncated pyramid shape including a flat portion 42a and an inclined portion 42b by pushing a part of the case 33 inward. The angle of the inclined portion 42b with respect to the horizontal plane is 45 °. In addition, the protrusion 42 is easily formed by pushing a part of the case 33 inward, but may have a solid structure. The flat portion 42a of the protrusion 42 has a through hole 35 provided inside the flat portion 42a and extends to the outside of the flat portion 42a to extend the first electronic component 31.
Is provided. That is, the width dimension A of the flat portion 42a,
When the width dimension B of the through hole and the width dimension C of the first electronic component 31 are in a relationship of C>A> B.

The optical receiver is configured as described above,
Since the ground pattern 38 is connected to the through-hole 35, the heat generated in the first electronic component 31 is also transmitted to the ground pattern 38 extending in the horizontal direction through the through-hole 35, and accordingly, the electronic circuit board 32 The heat is diffused throughout, and the heat release efficiency of the first electronic component 31 is improved. A second electronic component 34 fixed to the back surface of the electronic circuit board 32 is provided in a space between the back surface of the electronic circuit board 32 and the case 33 caused by the protrusion 42 formed on a part of the case 33. Are arranged, and the mounting density of the second electronic component 34 on the electronic circuit board 32 can be increased. Note that the second electronic component 34 is smaller than the heat generation amount of the first electronic component 31, and is simply attached to the back surface of the electronic circuit board 32 without taking special heat dissipation means for the second electronic component 34. Is fine.

A through hole 35 is provided directly below the first electronic component 31.
Since the flat portion 42a of the projection 42 is opposed to the back surface of the second 2, heat generated from the first electronic component 31 is transmitted to the projection 42a through the through hole 35, and then made of aluminum having high thermal conductivity. The gas is discharged to the outside from the case 33 which is configured and is in wide contact with the outside air. Moreover, since the heat radiation grease 41 having high thermal conductivity is filled in the through hole 35 and between the back surface of the electronic circuit board 32 and the flat portion 42a, the heat generated from the first electronic component 31 is not increased. Thus, the heat is more smoothly transmitted to the protrusion 42a, and the heat radiation efficiency of the first electronic component 31 is improved. Note that a heat dissipation sheet having high thermal conductivity may be interposed between the back surface of the electronic circuit board 32 and the flat portion 42a.

The cross-sectional area of the heat transfer passage from the first electronic component 31 to the inclined portion 42b of the projection 42 of the first embodiment is the same as that of the first conventional metal housing wall 26 shown in FIG.
When compared with the vertical portion 25b of the protruding portion 25, a part of which is gradually increased toward the bottom, the thermal resistance is reduced, and the thermal resistance is accordingly reduced through the protruding portion 42 from the first electronic component 31. Heat release is improved. Moreover, the inclination angle of the inclined portion 42b is 45 °,
A space for disposing the second electronic component 34 is provided between the back surface of the electronic circuit board 32 and the case 33. Further, since the width A of the flat portion 42a of the protrusion 42 is larger than the width B of the through hole 35, of the heat generated in the first electronic component 31, the heat flowing toward the flat portion 42b is less. The power is reliably transmitted to the flat portion 42a. Further, since the width dimension A of the flat portion 42a is smaller than the width dimension C of the first electronic component 31, the second dimension on the back surface of the electronic circuit board 32 is reduced.
The mounting area of the electronic component 34 is not reduced more than necessary.

Embodiment 2 FIG. 3 is a cross-sectional view of a main part of an optical transmitter that is an electronic apparatus according to Embodiment 2 of the present invention. First, the optical transmitter will be briefly described based on the block diagram of FIG. In the figure, 71 is, for example, 2.5 Gb /
s (gigabits per second) multiple electrical signals at 40 Gb / s
Is a data multiplexing unit for multiplexing into one electric signal. The signal multiplexed in the data multiplexing unit 71 is subjected to level amplification by the driver IC 72,
A modulation signal (high-frequency signal) for driving an LD (laser diode) 74 as an optical semiconductor component is generated. L
In D74, this modulated signal is converted into a 40 Gb / s optical signal and output. The output optical signal is transmitted to the lens 5
1. The signal is transmitted to another optical receiver via the optical fiber 50. Reference numeral 75 denotes an optical module on which the lens 51 and the LD 74 are mounted.

Next, the configuration of an optical transmitter, which is an electronic device, will be described. This optical transmitter also has a heat-generating first light-emitting device mounted on the surface of the electronic circuit board 32, similarly to the above-described optical receiver. Electronic component 31 (however, in this embodiment, it is the data multiplexing unit 71 or the driver IC 72, etc.)
And a plurality of second electronic components 34 mounted on the back surface of the electronic circuit board 32 and generating less heat than the first electronic components 31.
And the electronic circuit board 32, the first electronic component 31, and the second
And a case 33 accommodating the electronic component 34.
The structure of the electronic circuit board 32 is the same as that of the optical transmitter of the first embodiment, and the base material 3 is provided immediately below the first electronic component 31.
The heat radiation grease 41 is filled in the plurality of through-holes 35 penetrating the through hole 6 and connected to the ground pattern 38 extending in the horizontal direction.

The structure of the case 33 is the same as that of the first embodiment.
And has a truncated pyramid shape that is in contact with the back surface of the electronic circuit board 32 immediately below the first electronic component 31 via the heat radiation grease 41 and is thermally connected to the through hole 35. A projection 42 is formed. Further, when the width A of the flat portion 42a of the protrusion 42, the width B of the through hole, and the width C of the first electronic component 31 are also C>A> B, Embodiment 1
Has the same structure as that of the optical receiver.

In the optical transmitter having the above configuration, the electronic circuit board 3
2 is fixed to the case 33 by a fixing member 52. The electronic circuit board 32 has a through hole 53 for a fixing member thermally connected to the ground pattern 38, and the ground pattern 38 is thermally connected to the case 33 via the fixing member 52. As shown in FIG. 5, the fixing member 52 has a small-diameter portion 52 a inserted into the through-hole 53 for the fixing member from the back surface side of the electronic circuit board 32 to the front surface side, and a large-diameter portion abutting the back surface of the electronic circuit board 32. The electronic circuit board 32 is fixed to the small-diameter portion 52a by soldering. The case 33 has an insertion hole 33a into which the fixing member 52 is inserted.
2 has a caulking fixing portion 52c which is inserted into the insertion hole 33a and is caulked and fixed on the side opposite to the small diameter portion 52a.

The fixing member 52 which is a stepped pin having the above structure.
After the caulking fixing portion 52c is inserted into the insertion hole 33a of the case 33, the caulking fixing portion 52c is caulked, so that the fixing member 52 is fixed to the case 33. Then, the small diameter part 5
2a into the through hole 53 for the fixing member, and
The electronic circuit board 32 is fixed in the case 33 by brazing the head of 2 a with solder 54. In the prior art, for example, as shown in FIG.
1. Since the electronic circuit board 32 was fixed in the case 33 using the washer 62 and the solder 63, the electronic circuit board 3
Although the area occupied by the screw 60 on the surface of the second circuit board 2 is large, in this embodiment, the area of the solder 54 occupying the surface of the electronic circuit board 32 is reduced, and the mounting efficiency of the electronic circuit board 32 is improved accordingly. Further, since the fixing members 52 fixed at the four corners of the case 33 are stepped pins, the space between the back surface of the electronic circuit board 32 and the inner wall surface of the case 33 is more reliably secured by the fixing members 52 and the projections 42. Space is secured.

In the optical transmitter having the above configuration, case 3
The electronic circuit board 32 provided in the device 3 and the optical module 75 fixed to the side surface of the case 33 are electrically connected by a flexible film substrate 55. With such a configuration, the electronic circuit board 32 and the optical module 75
For example, even if deformation and expansion and contraction occur, the deformation and expansion and contraction are absorbed by the film substrate 55, and the optical transmitter can be used for a long time. The substrate on which the optical module is fixed and the electronic circuit substrate 32 may be electrically connected by a flexible film substrate.

Embodiment 3 FIG. 7 is a sectional view of a main part of an optical transmitter which is an electronic apparatus according to Embodiment 3 of the present invention. In the optical transmitter according to this embodiment, the groove 56 is formed between the signal pattern 37 for the first electronic component 31 and the area where the plurality of through holes 35 are formed. Also,
Unlike the first and second embodiments, the ground pattern 38 is not connected to the through hole 35. Note that a slit may be used instead of the groove. Also in this embodiment, the through hole 35 is provided directly below the first electronic component 31, and the flat portion 42 a of the projection 42 faces the back surface of the electronic circuit board 32. Electronic components 3
The heat generated from 1 is transmitted to the protruding portion 42a through the through hole 35, and then released to the outside from the case 33 made of aluminum having high thermal conductivity and in wide contact with the outside air. Moreover, the inside of the through hole 35,
In addition, since the heat radiation grease 41 having high thermal conductivity is filled between the back surface of the electronic circuit board 32 and the flat portion 42a, the heat generated from the first electronic component 31 more smoothly flows to the protrusion 42a. The heat is transmitted, and the heat radiation efficiency of the first electronic component 31 is improved.

Since the ground pattern 38 is not connected to the through hole 35, the heat generated by the first electronic component 31 is transferred to the electronic circuit board 32 via the ground pattern 38.
Does not spread throughout. In addition, the signal pattern 37
And the area where the plurality of through holes 35 are formed, the groove 56 which is a heat insulating groove is formed, so that the heat generated by the first electronic component 31 flows along the front and back surfaces of the electronic circuit board 32. Thus, the spread of the entire electronic circuit board 32 is suppressed. As a result, it is possible to reduce the heat stress applied to other surrounding electronic components while reliably releasing heat from the first electronic component, which is a heat generating component, and to be sensitive to temperature changes. Various electronic components can be mounted around the heat-generating electronic components.

Although the optical transmitter has been described as the electronic apparatus in the first embodiment, the present invention is also applied to, for example, an optical receiver and an optical transceiver in which the optical receiver and the optical transmitter are combined. can do. In the second and third embodiments, the optical receiver has been described as an electronic apparatus. However, the present invention can be applied to, for example, an optical transmitter and an optical transceiver. Although the BT resin is used as the base material of the electronic circuit board, a glass epoxy resin may be used. Further, in the second embodiment, the space between the electronic circuit board 32 and the case 33 as the support member is secured by using the stepped pins, but a board on which electronic components are mounted as the support member may be used. In the third embodiment, the through holes 35 and the protrusions 4 of the case 33 as the heat radiating member are provided.
Although the heat radiating member 2 is thermally connected, a heat radiating member may be provided between the case and the electronic circuit board as a heat radiating member, for example, and the heat radiating plate and the through hole may be thermally connected.

Embodiment 4 FIG. 8 is a schematic structural diagram of an electronic device mounted on an electronic circuit board according to the fourth embodiment.
The same reference numerals are given to the same portions as those of the conventional device shown in FIG. 2, and the description thereof will be simplified.

In FIG. 8, reference numeral 6 denotes an electronic circuit board made of a resin wiring board, 7 denotes a signal pattern formed on an inner layer of the electronic circuit board 6, and 8 denotes an electronic circuit board 6 similarly.
Is a ground pattern formed in the inner layer of the first embodiment. Reference numeral 9 denotes a plurality of through holes provided immediately below the mounting portion of the heat-generating component 1, and is connected to the ground pattern 8 by penetrating the ground pattern 8 in the electronic circuit board 6. 10
Is a projection surface for heat dissipation formed as a part of the case 3 by projecting a part of the case 3. The electronic circuit board 6
Are arranged such that the arrangement portion of the through hole 9 on the back surface thereof comes into contact with the projection surface 10 for heat radiation. 11 is
The back surface of the electronic circuit board 6 and the projecting surface 10 for heat radiation of the case 3
It is a space formed between the surrounding surface. The space 11 has a certain size that allows the low heat generation electric and electronic components to be mounted on the back surface of the electronic circuit board 6.

For this reason, in the fourth embodiment, the heat generated by the heat-generating component 1 passes through the through-hole 9 provided immediately below the mounting part of the heat-generating component 1, and contacts with the heat-dissipating projection surface 10. The heat is transferred to the entire case 3 through the case 3 and is radiated to the outside air from the case 3 having the effect of the radiator. Further, by connecting the through hole 9 to the ground pattern 8 formed in the inner layer of the electronic circuit board 6, the heat generated by the heat generating component 1 can be diffused to the entire electronic circuit board 6.

Further, since the heat-generating component 1 can be radiated only by contacting a part of the back surface of the electronic circuit board 6 with the case 3, electric / electronic components for low heat generation are also provided on the back surface of the electronic circuit board 6. It can be mounted, and the component mounting density can be increased to about twice that of the related art. In addition, resin wiring such as glass epoxy can be used without using an expensive ceramic substrate as the electronic circuit board 6. By using the substrate, it is possible to obtain a heat radiation effect equal to or higher than that of the conventional product.

Therefore, according to the fourth embodiment, it is possible to realize an electronic device mounted on an electronic circuit board which has a high mounting density, is inexpensive, and has excellent heat radiation characteristics.

Embodiment 5 Next, a fifth embodiment will be described with reference to FIG. FIG. 9 is a schematic structural diagram of an electronic device mounted on an electronic circuit board according to a fifth embodiment in which the fourth embodiment of the present invention is further improved. The same parts as those in the fourth embodiment are denoted by the same reference numerals. The description is omitted.

In FIG. 9, reference numeral 12 denotes a filler filled in the through hole 9, which is made of a material having high thermal conductivity such as copper. Reference numeral 13 denotes a heat-dissipating grease applied to a contact surface between the disposition portion of the through hole 9 on the back surface of the electronic circuit board 6 and the heat-dissipating protrusion 10 of the case 3 and is made of a material having high thermal conductivity. The other configuration is the same as that of the fourth embodiment.

In the electronic device mounted on the electronic circuit board configured as described above, the filler 12 filling the inside of the through-hole 9, the arrangement portion of the through-hole 9 on the back surface of the electronic circuit board 6, and the radiating projection surface 10 With the heat radiation grease 13 interposed in the contact portion with the case 3, a large amount of heat generated from the heat generating component 1 can be transmitted to the case 3.

Therefore, according to the fifth embodiment,
Not only has the same effect as in the fourth embodiment, but also an effect that an electronic device mounted on an electronic circuit board having more excellent heat dissipation characteristics can be realized.

Embodiment 6 FIG. Next, FIGS. 10 and 11
Embodiment 6 will be described with reference to FIG. FIG. 10 is a schematic structural diagram of an electronic device mounted on an electronic circuit board according to Embodiment 6 which is a further improvement of Embodiment 5 of the present invention.
FIG. 1 is a partial plan view of an electronic circuit board according to the sixth embodiment. The same portions as those in the fifth embodiment are denoted by the same reference numerals, and description thereof will be omitted.

First, the above-described improvements will be specifically described. In the above-described fifth embodiment, the conventional one and the fourth embodiment are the same, but the heat generated from the heat-generating component 1 is diffused throughout the electronic circuit board 6 so that the entire electronic circuit board 6 Is warmed, so that there is a possibility that other electronic components mounted on the electronic circuit board 6 may be subjected to thermal stress. In particular, when an electronic component that is sensitive to a temperature change is mounted around the heat-generating component, it is expected that there is a great possibility that the electronic component is mounted. The third embodiment is intended to further improve such a problem in the second embodiment.

In FIGS. 10 and 11, reference numeral 14 denotes a heat insulating groove formed on the surface of the electronic circuit board 6 and formed of a concave groove having a V-shaped cross section, which surrounds the heat-generating component 1 having a substantially square planar shape. Are formed in a substantially square shape. Reference numeral 15 denotes a heat insulating groove formed on the back surface of the electronic circuit board 6, which is formed from a concave groove having a V-shaped cross section similarly to the heat insulating groove 14, and has a substantially square shape at a position facing the heat insulating groove 14. Is formed. In the ground pattern 8, a portion where the through hole 9 is disposed is cut off so as not to be connected to the through hole 9. Note that other configurations are the same as those of the fifth embodiment.
Is the same as

In the electronic device mounted on the electronic circuit board configured as described above, the through hole 9 and the ground pattern 8
And a heat insulating groove 14 facing the front and back surfaces of the electronic circuit board 6 so as to surround the heat generating component 1.
By providing the heat-generating component 15, heat generated from the heat-generating component 1 is not transmitted to the ground pattern 8 via the through-hole 9, and the heat transmitted to the resin substrate is also transferred to the heat-insulating groove 14 surrounding the heat-generating component 1. Since the heat is shielded by the heat insulating groove 15 on the back surface, the heat stress from the heat generating component 1 applied to the electronic components around the heat generating component 1 can be reduced while the heat generating component 1 is reliably radiated. Therefore, according to the sixth embodiment, not only effects similar to those of the fifth embodiment are obtained, but also restrictions on mounting electric / electronic components around heat-generating component 1 are further relaxed. There is an effect that a small and inexpensive electronic device mounted on an electronic circuit board can be realized.

Next, a modification of the sixth embodiment will be described. Although the sixth embodiment has been described as a modification of the second embodiment, the sixth embodiment is described.
In the same manner as in the fourth embodiment, the filling of the filler 12 made of a good heat conductive material into the through hole 9, the arrangement of the through hole 9 on the back surface of the electronic circuit board 6, and the heat radiation projection surface It is also possible to adopt a configuration in which the heat radiation grease is not interposed on the contact surface with the heat sink 10. However, in this case, the structure can be simplified by not applying the filler 12 and the heat radiation grease, but it is inevitable that the heat radiation characteristic is slightly reduced.

[0062]

As described above, according to the electronic apparatus of the present invention, the electronic circuit board has a plurality of through holes that are thermally connected to the first electronic component immediately below the first electronic component. And the case has a protruding portion that is in contact with the back surface portion of the electronic circuit board immediately below the first electronic component and is thermally connected to the through hole.
The heat generated from the electronic components is transmitted to the protrusions through the through-holes and then released to the outside from the case that has come into wide contact with the outside air, and the electronic circuit board is thermally connected to the through-holes. Since the ground pattern is included, the heat generated from the first electronic component is also transmitted to the electronic circuit board through the through hole and the ground pattern, and the heat transfer heat radiation route through the through hole of the first electronic component is two. Routes are secured and heat dissipation performance is improved. Also, since the ground pattern of the electronic circuit board is thermally connected to the case via the through hole, if the temperature of the electronic circuit board side rises abnormally, much of that heat will be transferred to the ground pattern and through case. Released outside through the hole and case.

According to the electronic apparatus of the present invention, a plurality of ground patterns are provided, and these ground patterns have different shapes, so that the heat generated by the first electronic component is transferred to the electric circuit board by the heat. The heat can be selectively diffused through the through holes, and the heat distribution of the electronic circuit board can be controlled.

According to the electronic apparatus of the present invention, at least one second electronic component having a smaller heat generation than the first electronic component is mounted on the back surface of the electronic circuit board.
Since the electronic component is disposed in the space between the case and the back surface of the electronic circuit board around the protrusion, the mounting density of the electronic component is improved.

According to the electronic apparatus of the present invention, since the projection is formed by pushing a part of the case inward, the projection can be easily formed.

Further, according to the electronic apparatus of the present invention, since the projection has a solid structure, the heat capacity of the projection can be increased, and the heat radiation performance through the projection is improved.

Further, according to the electronic apparatus of the present invention, since the projection has a truncated pyramid shape including a flat portion and an inclined portion, a space can be secured between the back surface of the electronic circuit board and the case. The heat transfer cross-sectional area at the projection is enlarged, and the thermal resistance at the projection can be reduced.

Further, according to the electronic apparatus of the present invention, the flat portion of the projection has the through hole provided inside the flat portion, so that the flat portion of the heat generated by the first electronic component is formed in the flat portion. The heat flowing toward the flat portion is reliably transferred. Further, the first electronic component is provided to extend to the outside of the flat portion, and the width of the flat portion is smaller than the width of the first electronic component. Therefore, a mounting area on the back surface of the electronic circuit board is required. It will not be narrowed further.

Further, according to the electronic apparatus of the present invention, the case has the protruding portion abutting on the back surface portion of the electronic circuit board immediately below the first electronic component and thermally connected to the electric circuit board. Since the protrusion has a truncated pyramid shape including a flat portion and an inclined portion, a space can be secured between the back surface of the electronic circuit board and the case, and the heat transfer cross-sectional area of the protrusion is increased. The thermal resistance in the part can be reduced.

Further, according to the electronic apparatus of the present invention, since the second electronic component is mounted on the back surface of the electronic circuit board facing the inclined portion, the space between the back surface of the electronic circuit board and the case is reduced. Can be used effectively.

According to the electronic apparatus of the present invention, the through holes are filled with the heat radiation grease.
The heat generated from the electronic component is more smoothly transmitted to the protrusion, and the heat radiation performance of the first electronic component is improved.

According to the electronic apparatus of the present invention, since the heat radiation grease or the heat radiation sheet is interposed between the electronic circuit board and the flat portion of the case, the heat generated from the first electronic component is The heat is more smoothly transmitted to the protrusions, and the heat radiation performance of the first electronic component is improved.

According to the electronic apparatus of the present invention, the electronic circuit board is fixed to the case by the fixing member, and the ground pattern is thermally connected to the case via the fixing member. Part of the heat generated from the component is released to the outside through the through hole, the ground pattern, the fixing member, and the case, and the heat radiation performance of the first electronic component is improved.

According to the electronic apparatus of the present invention, the electronic circuit board has the through hole for the fixing member thermally connected to the ground pattern, and the fixing member has the through hole for the fixing member in the through hole for the fixing member. A stepped pin having a small-diameter portion inserted from the back side of the circuit board to the front side, and a large-diameter portion in contact with the back side of the electronic circuit board, and the electronic circuit board is fixed to the small-diameter section by soldering The first
Part of the heat generated from the electronic component is released outside through the through hole, the ground pattern, the fixing member, and the case, and the heat radiation performance of the first electronic component is improved. Further, the area of the solder occupying the surface of the electronic circuit board is reduced, and the mounting efficiency of the electronic circuit board is improved accordingly. Further, since the fixing member is a stepped pin, a space between the back surface of the electronic circuit board and the inner wall surface of the case is reliably ensured.

According to the electronic device of the present invention, the case has the insertion hole into which the stepped pin is inserted, and the stepped pin is inserted into the insertion hole on the side opposite to the small-diameter portion and swaged. The stepped pin is easily fixed to the case because it has the swaged fixing portion to be fixed.

According to the electronic apparatus of the present invention, since the base of the electronic circuit board is made of BT resin,
A material excellent in thermal conductivity and electrical characteristics can be obtained at low cost.

According to the electronic apparatus of the present invention, the first
Are electronic circuit components that transmit signals from the DC level to the high-frequency level with the optical semiconductor component, so that the heat radiation performance of the electronic circuit component is improved.

According to the electronic apparatus of the present invention, a stepped pin is provided between the electronic circuit board and the support member, and the stepped pin is inserted into the insertion hole formed in the electronic circuit board. Since the electronic circuit board has a small-diameter portion inserted from the back surface side to the front surface side and a large-diameter portion abutting on the back surface of the electronic circuit board, the electronic circuit board is fixed to the small-diameter portion of the front-stage pin by soldering. In addition, the area of the solder occupying the surface of the electronic circuit board is reduced, and the mounting efficiency of the electronic circuit board is improved accordingly. Also, since the fixing member is a stepped pin,
The space between the back surface of the electronic circuit board and the inner wall surface of the support member is reliably ensured.

Further, according to the electronic apparatus of the present invention, since the stepped pin has the caulking fixing portion which is inserted into the insertion hole of the support member and caulked and fixed on the side opposite to the small diameter portion.
The stepped pin can be easily fixed to the support member.

Further, according to the electronic apparatus of the present invention, a space is formed between the electronic circuit board and the support member by the large diameter portion of the stepped pin, and both sides of the electronic component are mounted on the electronic circuit board. Is made possible, the mounting efficiency of the electronic circuit board is improved.

Further, according to the electronic apparatus of the present invention, since the electronic circuit board and the optical semiconductor component are electrically connected to each other by the film substrate, the degree of freedom in assembly is increased, and the assemblability can be improved. . Further, even if deformation and expansion and contraction occur in an electronic circuit board, an optical semiconductor component, and the like, the deformation and expansion and contraction are absorbed by the film substrate, and the electronic device can be used for a long time.

According to the electronic apparatus of the present invention, an electronic circuit having a plurality of through-holes mounted with a heat-generating electronic component and directly connected to the heat-generating electronic component immediately below the heat-generating electronic component. Since the substrate and the heat-dissipating member that is in contact with the back surface portion of the electronic circuit board directly below the heat-generating electronic component and that is thermally connected to the through-hole, heat generated from the electronic component is The heat is transmitted to the heat radiating member through the hole. Further, the electronic circuit board has a groove or a slit formed between the signal pattern for the heat-generating electronic component and the area in which the plurality of through holes are formed. Spreading of the entire electronic circuit board along the front and back surfaces of the circuit board is suppressed, and as a result, thermal stress applied to other surrounding electronic parts of the electronic parts is reduced while reliably dissipating the electronic parts. Thus, electronic components that are sensitive to temperature changes can also be mounted around the heat-generating electronic components.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an optical receiver according to a first embodiment of the present invention.

FIG. 2 is a block diagram of the optical receiver in FIG. 1;

FIG. 3 is a sectional view of a main part of an optical transmitter according to a second embodiment of the present invention.

FIG. 4 is a block diagram of the optical transmitter in FIG. 3;

5 (a) is a view when the caulking fixing portion of the fixing member of FIG. 3 is inserted into the insertion hole of the case, and FIG. 5 (b) is a case where the caulking fixing portion of the fixing member of FIG. FIG. 4 is a view when inserted into an insertion hole and swaged.

FIG. 6 is a view showing fixing means for fixing an electronic circuit board to a conventional case.

FIG. 7 is a sectional view of a main part of an optical transmitter according to a third embodiment of the present invention.

FIG. 8 is a schematic structural diagram of an electronic device mounted on an electronic circuit board according to Embodiment 4 of the present invention.

FIG. 9 is a schematic structural diagram of an electronic device mounted on an electronic circuit board according to Embodiment 5 of the present invention.

FIG. 10 is a schematic structural diagram of an electronic device mounted on an electronic circuit board according to Embodiment 6 of the present invention.

11 is a plan view of the electronic circuit board shown in FIG.

FIG. 12 is a schematic structural view showing an electronic device mounted on an electronic circuit board according to a first conventional example.

FIG. 13 is a schematic structural view showing an electronic device mounted on an electronic circuit board according to a second conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Heating component, 3 case, 5 cover, 6 electronic circuit board, 7 wiring pattern, 8 ground pattern, 9 through hole, 10 heat radiation projection surface, 11 space, 12
Filler, 13 Thermal grease, 14 Thermal insulation groove, 15 Thermal insulation groove, 31 First electronic component, 32 Electronic circuit component, 3
3 case, 35 through hole, 36 base material, 37 signal pattern, 38 ground pattern, 41 heat radiation grease, 42 projection, 42a flat portion, 42b inclined portion, 52 fixing member, 52a small diameter portion, 52b large diameter portion, 52c caulking Fixing part, A53 Through hole for fixing member, 54 Solder, 55 Film substrate.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 25/18

Claims (21)

[Claims] 1. An electronic apparatus comprising: an electronic circuit board having a surface on which a heat-generating first electronic component is mounted; and a case accommodating the electronic circuit board, wherein the electronic circuit board includes the first electronic component. First below the part
A plurality of through holes that are thermally connected to the electronic component, and a ground pattern that is thermally connected to the through hole. An electronic device having a projection abutting on a back surface portion and thermally connected to the through hole. 2. The electronic device according to claim 1, wherein a plurality of the ground patterns are provided, and the ground patterns have different shapes. 3. At least one second electronic component having a lower heating value than the first electronic component is mounted on a back surface of the electronic circuit board, and the second electronic component is provided around a periphery of the protrusion. The electronic device according to claim 1, wherein the electronic device is disposed in a space between a back surface of the electronic circuit board and the case. 4. The electronic device according to claim 1, wherein the protrusion is formed by pushing a part of the case inward. 5. The electronic device according to claim 1, wherein the protrusion has a solid structure. 6. The electronic device according to claim 1, wherein the protrusion has a truncated pyramid shape including a flat portion and an inclined portion. 7. The flat portion of the projection, wherein the through hole is provided inside the flat portion, and the first electronic component extending to the outside of the flat portion is provided. The electronic device according to claim 6. 8. An electronic device comprising: an electronic circuit board having a surface on which a heat-generating first electronic component is mounted; and a case accommodating the electronic circuit board, wherein the case is located immediately below the first electronic component. And a protrusion that is in contact with the back surface of the electronic circuit board and is thermally connected to the electric circuit board. The protrusion has a truncated pyramid shape including a flat portion and an inclined portion. And electronic equipment. 9. The electronic device according to claim 6, wherein a second electronic component is mounted on a back surface of the electronic circuit board facing the inclined portion. 10. The electronic device according to claim 1, wherein the through hole is filled with heat radiation grease. 11. The electronic device according to claim 1, wherein a heat radiation grease or a heat radiation sheet is interposed between the electronic circuit board and the flat portion of the case. 12. The electronic circuit board according to claim 1, wherein the electronic circuit board is fixed to a case by a fixing member, and the ground pattern is thermally connected to the case via a fixing member. Electronics. 13. The electronic circuit board has a through hole for a fixing member thermally connected to the ground pattern, and the fixing member is formed in the through hole for the fixing member from the back side of the electronic circuit board. A small diameter part inserted on the front side,
13. A stepped pin having a large-diameter portion abutting on the back surface of the electronic circuit board, wherein the electronic circuit board is fixed to the small-diameter portion by soldering. An electronic device according to any of the above. 14. The case has an insertion hole into which the stepped pin is inserted, and the stepped pin is inserted into the insertion hole and fixed by caulking on a side opposite to the small diameter portion. The electronic device according to claim 13, comprising: 15. The electronic device according to claim 1, wherein a base material of the electronic circuit board is made of a BT resin. 16. The electronic device according to claim 1, wherein the first electronic component is an electronic circuit component that transmits a signal from a DC level to a high-frequency level with an optical semiconductor component. An electronic device according to any of the above. 17. An electronic apparatus comprising: an electronic circuit board; and a support member supporting the electronic circuit board, wherein a stepped pin is provided between the electronic circuit board and the support member. A small-diameter portion inserted into the insertion hole formed in the electronic circuit board from the back surface side to the front surface side of the electronic circuit board, and a large-diameter portion contacting the back surface of the electronic circuit board; An electronic device, wherein a circuit board is fixed to a small-diameter portion of a pin with a front step. 18. The caulking pin according to claim 17, wherein the stepped pin has a caulking fixing portion which is inserted into an insertion hole of the support member and is caulked and fixed on a side opposite to the small diameter portion. Electronic device as described. 19. A large-diameter portion of the stepped pin forms a space between the electronic circuit board and the support member, thereby enabling double-sided mounting of electronic components on the electronic circuit board. A feature according to claim 17 or claim 18.
An electronic device according to claim 1. 20. An electronic device comprising an electronic circuit board, a case accommodating the electronic circuit board, and an optical semiconductor component fixed to the case, wherein the electronic circuit substrate and the optical semiconductor component are a film substrate. An electronic device characterized by being electrically connected by: 21. An electronic circuit board having a plurality of through-holes, on which a heat-generating electronic component is mounted, and which is thermally connected to the heat-generating electronic component immediately below the heat-generating electronic component; A heat dissipating member abutting on a back surface portion of the electronic circuit board and thermally connected to the through hole; wherein the electronic circuit board includes a signal pattern for the heat-generating electronic component; An electronic device, wherein a groove or a slit is formed between an area where a hole is formed.