JPH04354361A - Electronic device - Google Patents

Abstract

PURPOSE:To prevent the outflow of an adhesive used for the junction between a frame body and a circuit board. CONSTITUTION:This has a frame body 10, where a stairs-shaped stepped part 21 which has a horizontal plane 21h which contacts with the periphery on the side of the wiring face of a circuit board 50 and is joined with the circuit board with an adhesive is made at the inner sidewall, and at the wiring face of the circuit board is made the dummy wiring 54 by a circuit pattern which is made inside a minute interval apart from the inside boundary 21a of the contact area with the horizontal plane. It follows that the surplus adhesive, which is protruded out of the adhesive interposed between the horizontal plane and the circuit board, comes to be reserved in the minute space between the inside boundary and the dummy wiring, and the adhesive is prevented from flowing into the wiring face of the circuit board over the dummy wiring.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device with improved packaging density, and more particularly to a device that facilitates bonding of a board to a frame and prevents the production of defective products.

0002

BACKGROUND OF THE INVENTION Conventionally, there has been known a device in which a circuit board on which a semiconductor integrated circuit is mounted is mounted in two stages in one package (for example, Japanese Patent Application Laid-open No. 1-147850).
. In this device, a two-tiered circuit board is attached inside the package with an adhesive.

0003

[Problems to be Solved by the Invention] However, in such electronic devices, there is no way to bond the board to the package with adhesive, and the excess adhesive that protrudes from the bonding surface is
It protrudes onto the surface of its own board or falls onto the board below. For this reason, this excess adhesive adheres to the electrical connection portions on the substrate, causing connection failures and abnormal transmission of bonding power during bonding, leading to unreliable bonding. Furthermore, the adhesive may adhere to electrical connection leads between the boards, causing connection failures. Furthermore, the heat dissipation effect deteriorates due to the adhesive, and differences in thermal expansion coefficient and viscosity between the adhesive and the substrate, connection leads, etc. can cause distortions, cracks, and deterioration of characteristics. There is a problem.

The present invention has been made to solve the above-mentioned problems, and its purpose is to facilitate the bonding of a circuit board into a package in an electronic device mounted with a circuit board, and to provide an electronic circuit using an adhesive. The objective is to prevent negative effects on the equipment and prevent connection failures.

[0005]

[Means for Solving the Problems] The structure of the invention for solving the above problems comprises a case, and a horizontal surface that is in contact with the periphery of the wiring surface of the circuit board and is bonded to the circuit board with an adhesive. A step-like stepped part is formed on the inner wall of the circuit board, and the wiring surface of the circuit board has a stepped part formed on the inner side at a minute distance from the inner boundary line of the contact area with the horizontal surface. A dummy wiring is formed using a circuit pattern. Another feature is that a notch is formed on the inner boundary line side of the horizontal surface of the stepped portion.

[0006]

[Operation] The peripheral portion of the circuit board on the wiring surface side and the horizontal surface of the stepped portion formed on the frame are bonded by adhesive. At this time, excess adhesive flows out onto the wiring surface of the circuit board beyond the inner border of the contact area with the horizontal surface of the circuit board.

However, in this circuit board, dummy wiring formed by a circuit pattern is formed on the inside with a minute gap from the inner boundary line. Therefore, the excess adhesive will be stored in the tiny gap between the inner boundary line and the dummy trace, and the adhesive will be prevented from flowing beyond the dummy trace to the inside of the wiring surface of the circuit board. Ru. Therefore, it may adversely affect the electronic circuits mounted on the board,
It will not adhere to the connection parts on the board and cause connection failures. In addition, the occurrence of cracks and deterioration of the heat dissipation effect due to differences in thermal expansion coefficient and viscosity between the substrate and the adhesive are prevented. Furthermore, since the notch is formed on the inner boundary line side of the horizontal surface, the adhesive is stored in the space formed by the notch and the substrate, and does not leak out to other parts.

[0008]

EXAMPLES The present invention will be explained below based on specific examples. FIG. 1 is a sectional view of the electronic device 1 according to the present embodiment, FIG. 2 is a perspective view of the frame 10, and FIG. 3 is a cross-sectional view of the frame 10.
4 is a perspective view of an apparatus in which a first circuit board 50 is mounted on the lower stage of the frame body 10, FIG. 4 is a perspective view of an apparatus in which a second circuit board 52 is mounted on the middle stage of the frame body 10, and FIG. FIG.

(1) Structure of the entire device As shown in FIG. 5, the frame 10 is made of resin and has a substantially rectangular parallelepiped shape. The frame body 10 has an upper opening 12 that is open to the external space on the upper side and a lower opening 11 that is open to the external space on the lower side in the illustrated state. Further, on the inner surface of the frame 10, in order from the lower opening 11 side, a first stepped portion 21, a second stepped portion 22,
Third stepped portion 23, fourth stepped portion 24, fifth stepped portion 2
5 is formed. Each stepped part 21, 22, 23, 24
, 25 are horizontal surfaces 21h, 22h, 23h, 24h, and 25h whose normals are directed in the Y-axis direction (vertical axis direction), respectively.
and the vertical plane 21v whose normal line faces the X-axis direction (horizontal axis direction)
, 22v, 23v, 24v, and 25v.

As shown in FIG. 6, the first circuit board 50 has an insulating layer formed on a metal plate 40 made of aluminum, and a circuit pattern formed on the surface of the insulating layer. The circuit board integrally formed on this metal plate 40 is usually called a metal board. The peripheral portion 50a (FIG. 6) of the first circuit board 50 is bonded to the horizontal surface 21h of the first stepped portion 21 with an adhesive, so that the lower opening 11 is shielded by the metal plate 40. . Note that the height of the vertical surface 21v of the first stepped portion 21 is equal to the thickness of the above-mentioned metal board in which the metal plate 40 and the first circuit board 50 are integrated, and The back surface 41 of the metal plate 40 constitutes the same plane.

As shown in FIGS. 1 and 3, on the first circuit board 50, there is a power M that handles a large current and generates a large amount of heat.
A power supply circuit 51 made up of so-called power elements such as OS transistors and power transistors is mounted.

The metal plate 43 is disposed on the third stepped portion 23, as shown in FIGS. 1 and 19. That is, the peripheral portion of the back surface 44 of the metal plate 43 is bonded to the horizontal surface 23h of the third stepped portion 23 with an adhesive. A second circuit board 52 is bonded to the surface 45 of the metal plate 43 with an adhesive. Then, on the second circuit board 52,
A control circuit 53 that handles a relatively small current and generates little heat is mounted. These power supply circuit 51 and control circuit 53
is coated with silicone gel 16, as shown in FIG. This gel may be made of other resins besides silicone. This gel has a heat insulating effect, so if an element that handles a large current is formed on the second circuit board 52, the heat from that element will be transferred to the first circuit board 50 due to the action of the gel on it. Heat is accumulated between the heat and the second circuit board 52 and cannot escape to the outside of the device. According to the structure of the present invention, the heat generated from the elements formed on the first circuit board 50 can be radiated to the outside via the metal plate 40 with a high heat radiation effect, and Since the elements disposed in the device do not generate much heat, no heat is trapped inside the device.

Further, a metal plate 46 for shielding the upper opening 12 is disposed on the fifth stepped portion 25 of the frame body 10. That is, the peripheral portion of the back surface 47 of the metal plate 46 is bonded to the horizontal surface 25h of the fifth stepped portion 25 with an adhesive. The surface 48 of the metal plate 46 is in contact with the outside air. In this way, the frame 10, the metal plate 40, and the metal plate 46 can
cases are constructed. This device consists of a resin frame 1
Aluminum metal plate 4 that shields the lower opening 11 of 0
Since a metal plate 43 made of aluminum is disposed in the middle of the frame 10 and a second circuit board 52 made of ceramic is provided on the metal plate 43, this device can be installed in the engine room of an automobile, etc. Even if placed in a high-temperature environment, warping due to the difference in coefficient of thermal expansion between the resin of the frame 10 and the metal plate is prevented, and the second circuit board 52 made of ceramics is prevented from cracking and the second circuit board 52 is prevented from warping. Deterioration in reliability, such as poor bonding of the bonded portions on the circuit board 52, was prevented. Moreover, the upper opening 12 of the frame 10
Since the metal plate 46 made of aluminum is also provided in the frame 10, warping of the frame 10 and poor joining of the joints on the circuit board due to the warping can be further prevented. In addition, JP-A-1
The device with the structure shown in Figure 1 of -147850 consists of a resin frame and a metal lid member, so the frame may warp due to the difference in thermal expansion coefficient between the resin and the metal, and the inside of the frame may warp. The ceramic substrate provided on the substrate may crack, and the reliability of the joints on this substrate may deteriorate.

On the other hand, a connector case 14 is formed on one side of the frame 10, and lead pins 60 and 61 protrude inside the connector case 14. The lead pin 60 is made by bending a metal plate on which a large number of leads are formed in a comb shape shown in FIG. 7 as shown in FIG.
It is embedded inside the 0 by insert molding. As shown in FIG. 1, a pin 60a formed at one end of the lead pin 60 projects into the internal space of the connector case 14, and a bonding portion 6 formed at the other end.
0b is installed in an exposed state on the horizontal surface 22h of the second stepped portion 22. This bonding portion 60b is the bonding portion 81 of the wiring pattern on the first circuit board 50.
and are electrically connected by wire bonding.

Also, like the lead pin 60, the lead pin 61 is formed by bending a metal plate shown in FIG. 9 into the shape shown in FIG. A pin 61a formed at one end of the lead pin 61 protrudes into the internal space of the connector case 14, and a bonding portion 61a formed at the other end
b is installed in an exposed state on the horizontal surface 24h of the fourth stepped portion 24. The bonding portion 82 of the wiring pattern on the second circuit board 52 and the bonding portion 61b of the lead pin 61 are electrically connected by wire bonding. In addition, in the lead pins 60 and 61, frame portions 60c and 61 that hold each lead in common
c are respectively cut with a cutter after resin molding, and each lead is electrically insulated.

Further, connection leads 63 are inserted into the frame 10 to electrically connect only the first circuit board 50 and the second circuit board 52 and prevent pins from protruding for taking out signals to the outside. It is buried by molding. The connection lead 63 is obtained by bending the comb-shaped metal plate shown in FIG. 11 into the shape shown in FIG. 12. This connection lead 63 connects the bonding portion 63a exposed on the horizontal surface 22h of the second stepped portion 22 and the horizontal surface 22h of the fourth stepped portion 24.
The bonding portion 63b is exposed on the upper portion h, and the tip portion 63c thereof is bent toward the bottom of the frame 10. A frame portion 63 that holds each lead in common
d and 63e are cut with a cutter after resin molding, and the respective leads are insulated from each other. And the bonding part 63
a is electrically connected to the bonding part 81 of the wiring pattern on the first circuit board 50 by wire bonding, and the bonding part 63b is electrically connected to the bonding part 82 of the wiring pattern on the second circuit board 52 by wire bonding. It is connected to the. This connection lead 63 electrically connects part of the wiring between the first circuit board 50 and the second circuit board 52.

Furthermore, a capacitor box 15 is formed on the side surface of the frame 10, as shown in FIG. 2, and the capacitor box 15 includes capacitors 56,
57 is stored horizontally. These capacitors 56 and 57 are mounted on the first circuit board 5 due to mounting space.
0 and the second circuit board 52. By housing the capacitors 56 and 57, which have a relatively large volume and height, in the capacitor box 15 formed separately on the side surface of the frame 10 as in this embodiment, the overall mounting efficiency of the electronic device 1 can be improved. can. A connection lead 64 electrically connected to the capacitor 56 is embedded in the frame 10 by insert molding. The connection lead 64 is shown in FIG.
This is obtained by bending the metal plate shown in FIG. 14 into the shape shown in FIG. This connection lead 64 includes a bonding portion 64a exposed on the horizontal surface 22h of the second stepped portion 22, a terminal portion 64b provided upright on the capacitor box 15, and a frame portion 64.
It has c. The frame portion 64c is cut with a cutter after the frame body 10 is formed. Moreover, the bonding part 64a
is electrically connected to the wiring pattern of the first circuit board 50 by wire bonding, and the terminal portion 64b is connected to the leads 56a, 56b of the capacitor 56 by electric welding.

On the other hand, on the side of the frame body 10 opposite to the side where the connector case 14 is formed, a comb-shaped metal plate shown in FIG. Bent into a U-shaped groove (shape with a handle attached to a U-shaped groove)
A connection lead 62 is embedded inside the frame 10 by insert molding. The bonding portion 62a formed at one end of the connection lead 62 is connected to the second stepped portion 2.
2 is installed in an exposed state on the horizontal surface 22h of the middle part 62.
g is buried inside the frame, the bonding part 62b of the connection lead 62 is installed in an exposed state on the horizontal surface 24h of the fourth stepped part 24, and the other tip part 62c is installed in the first stepped part 21.
It protrudes into a groove 26 formed on a horizontal surface 21h. Note that the frame portion 62d that holds the leads in common projects into the groove 26 immediately after the frame body 10 is formed, but is then cut with a cutter. Similarly, frame part 6
2e is also cut after molding, and each lead is insulated and separated. At this time, cuts are formed in the frame portions 62d and 62e to facilitate cutting.

Further, as shown in FIG. 1, the bonding portion 62a of the connection lead 62 and the bonding portion 83 of the wiring pattern of the first circuit board 50 are electrically connected by wire bonding. 62b and the bonding portion 84 of the wiring pattern of the second circuit board 52 are electrically connected by wire bonding. In this way, electrical connection is made between the first circuit board 50 and the second circuit board 52 using the connection leads 62.

Further, on the side of the frame 10 where the connection lead 62 is provided, a connection lead 6 having a shape similar to the connection lead 64 shown in FIG. 14 is provided adjacent to the connection lead 62.
5 is buried. The connection lead 65 includes a bonding portion 65a exposed and disposed on the horizontal surface 22h of the second stepped portion 22 and a terminal portion 65b erected within the capacitor box 15. And the bonding part 6
5a and the wiring pattern of the first circuit board 50 are electrically connected by wire bonding, and the lead 57b of the capacitor 57 is connected to the terminal portion 65b by electric welding.

(2) Detailed structure of the metal substrate (metal plate 40, first circuit board 50) On the first circuit board 50, as shown in FIG. 6, a circuit for the power supply circuit 51 shown in FIG. Wiring is formed. Then, in a state where the first circuit board 50 is attached to the first stepped portion 21, the horizontal surface 21h of the first stepped portion 21 is
A minute gap Δ1 is created from the inner boundary line 21a shown in FIGS. 5 and 6.
A dummy wiring 54 is formed in a convex shape on the inner side of the ridge. Furthermore, a recess 55 in which no wiring is formed is formed inside the dummy wiring 54.

The functions of the dummy wiring 54 and the recess 55 are as follows. When the first circuit board 50 formed on the metal plate 40 is bonded to the horizontal surface 21h of the first stepped portion 21 with adhesive, the excess adhesive crosses the inner boundary line 21a of the horizontal surface 21h to the first stepped portion 21. flows into the inside of the circuit board 50,
It may adhere to the connection portion 59 of the integrated circuit 58 mounted on the first circuit board 50 and cause a connection failure, or may cause abnormal conduction of bonding power during bonding, reducing the reliability of bonding. Moreover, it may adhere to the bonding parts 81, 83, etc. of the circuit wiring, causing bonding defects. At this time, as shown in FIG. 17, the dummy wiring 54 formed on the first circuit board 50 is
It acts to prevent the inflow of water. That is, the excess adhesive 17 is accumulated in the minute gap Δ1 between the boundary line 21a of the horizontal surface 21h and the dummy wiring 54. In addition, there is a lot of excess adhesive, and it goes over the dummy wiring 54, and furthermore,
Even if the adhesive flows inside the first circuit board 50, it is trapped in the recess 55 formed inside the dummy wiring 54 and does not flow further inside the recess 55. As a result, damage to the element due to adhesive is prevented,
Wire bonding defects are prevented from occurring. Incidentally, the dummy wiring 54 is a line or a ground line that is unrelated to electrical wiring.

(3) Detailed configuration of the first stepped portion 21
As shown in FIG. 17, the stepped portion 21 has a notch 21b formed on the inner boundary line 21a side of the horizontal surface 21h. The cutout 21b may be cut out diagonally as shown in the figure, or may be cut out in a rectangular or U-shape as shown in FIGS. 18(a) and 18(b).

The function of the notch 21b is as follows. When the first circuit board 50 formed on the metal plate 40 is bonded to the first stepped portion 21 with adhesive, the excess adhesive 17 is bonded to the notch 21b, the surface of the first circuit board 50, and the dummy. Wiring 54
It is stored between. As a result, the excess adhesive 17 is prevented from flowing into the first circuit board 50, and the influence of the adhesive on the integrated circuit 58 of the power supply circuit 51 can be prevented.

[0025] Also, the excess adhesive 17 is removed from the second stepped portion 22.
The bonding portion 60b of the lead pin 60, the bonding portion 63a of the connection lead 63, the bonding portion 64a of the connection lead 64, and the bonding portion 62a of the connection lead 62 disposed on the horizontal surface 22h are prevented from rising to the horizontal surface 22h. Also, it is possible to prevent wire bonding defects from occurring due to the adhesive 17 adhering to the bonding portion 65a of the connection lead 65.

(4) Detailed configuration diagram 1 of the third stepped portion 23
As shown in FIG. 9, a groove 23b is formed on the inner boundary line 23a side of the horizontal surface 23h of the third stepped portion 23, and a groove 23d is formed on the outer boundary line 23c. The grooves 23b and 23d may have a triangular shape other than the illustrated rectangular shape. Also, Figure 1
It may have a structure similar to 8.

[0027] A groove 23b formed in the third stepped portion 23;
The action of 23d is as follows. When the metal plate 43 is bonded to the horizontal surface 23h of the third stepped portion 23 with adhesive, excess adhesive 17 is stored in this groove 23b. As a result,
The excess adhesive 17 is removed from the second layer below the horizontal surface 23h.
The bonding portion 60b of the lead pin 60, the bonding portion 63a of the connection lead 63, the bonding portion 64a of the connection lead 64, and the connection lead 62 are prevented from hanging down on the horizontal surface 22h of the stepped portion 22 and are arranged on the horizontal surface 22h. bonding part 62a and connection lead 65
It is possible to prevent wire bonding defects from occurring due to adhesive adhering to the bonding portion 65a. Further, the groove 23b allows the horizontal surface 2 of the third stepped portion 23 of the silicone gel 16 filled on the first circuit board 50 to
3h is prevented from creeping up, the adhesive is easily attached to the horizontal surface 23h, and poor adhesion between the horizontal surface 23h and the metal plate 43 is prevented. In order to prevent the horizontal surface 23h of the third stepped portion 23 of the silicone gel 16 from creeping up, the vertical surface 22v of the second stepped portion 22 is
A stepped portion may be formed that protrudes perpendicularly to the surface.

Further, excess adhesive 17 is also stored in the groove 23d. As a result, the excess adhesive 17 is transferred to the third stepped portion 2.
3, and adheres to the wiring pattern of the second circuit board 52 bonded on the metal plate 43, and is disposed on the horizontal surface 24h of the fourth stepped portion 24. The bonding portion 61b of the lead pin 61, the bonding portion 63b of the connection lead 63, and the bonding portion 62b of the connection lead 62 are prevented from adhering to the bonding portion 61b of the lead pin 61, the bonding portion 63b of the connection lead 62, and wire bonding defects can be prevented from occurring.

(5) Specific configuration of metal plate 43 Metal plate 4
3, as shown in FIGS. 19 and 20, the third stepped portion 23
When the metal plate 43 is placed on the horizontal surface 23h, it is slightly smaller than the shape shown by the outer boundary line 23c of the horizontal surface 23h.
It is configured to create a minute gap Δ2 between it and the vertical surface 23v. Several protrusions 43a are formed on the peripheral edge of the metal plate 43 toward the outside (in the direction of the vertical surface 23v). Moreover, several protrusions 23e are formed on the vertical surface 23v toward the inside (toward the metal plate 43).

The functions of the protrusions 43a and 23e are as follows. The protrusions 43a and 23e are arranged so that the metal plate 43 is connected to the third stepped portion 2.
This is for positioning when placed on the metal plate 43 and the vertical surface 23v, and is for forming a minute gap Δ2 between the metal plate 43 and the vertical surface 23v. Also, due to this gap Δ2, the bonding portion 61b of the lead pin 61, the bonding portion 63b of the connection lead 63, and the bonding portion 6 of the connection lead 62
2b and the metal plate 43 are insulated and separated. Further, the excess adhesive 17 is stored in this minute gap Δ2, and the adhesive 1
7 is prevented from climbing up the vertical surface 23v. As a result, the excess adhesive 17 is transferred to the vertical surface 23 of the third stepped portion 23.
v and attaching to the wiring pattern of the second circuit board 52 bonded on the metal plate 43, and the lead pins 61 disposed on the horizontal surface 24h of the fourth stepped portion 24. This prevents the wire from adhering to the bonding portion 61b and the bonding portion 62b of the connection lead 62, thereby preventing wire bonding defects from occurring.

(6) Detailed configuration diagram 2 of the fifth stepped portion 25
As shown in FIG. 1, a groove 25b is formed on the inner boundary line 25a side of the horizontal surface 25h of the fifth stepped portion 25. The groove 25b may have a triangular shape other than the illustrated rectangular shape. Furthermore, the structure may be similar to that shown in FIG.

The function of the groove 25b formed in the fifth stepped portion 25 is as follows. The metal plate 46 is the fifth stepped portion 25
is bonded to the horizontal surface 25h with adhesive. At this time, excess adhesive 17 is stored in this groove. As a result, excess adhesive hangs down from the horizontal surface 25h, and the fourth stepped portion 24
Wire bonding defects due to adhesion to the bonding 61b of the lead pin 61 and the bonding 62b of the connection lead 62 disposed in the wire are prevented. Further, the adhesive 17 is also prevented from adhering to the wiring pattern of the second circuit board 52. Further, the groove 25b prevents the silicone gel 16 filled on the second circuit board 52 from creeping up onto the horizontal surface 25h of the fifth stepped portion 25, making it easier for adhesive to adhere to the horizontal surface 25h. Poor adhesion between the horizontal surface 25h and the metal plate 46 is prevented. In order to prevent the horizontal surface 25h of the fifth stepped portion 25 of the silicone gel 16 from creeping up, a stepped portion protruding perpendicularly to the vertical surface 24v of the fourth stepped portion 24 is provided on the vertical surface 24v of the fourth stepped portion 24. It may be formed.

(7) Detailed structure of lead pins 60 and 61 The lead pins 60 and 61 are constructed by bending the flat metal plates shown in FIGS. 7 and 9 into the shapes shown in FIGS. 8 and 10, respectively. The pitch of each lead piece is the bonding part 60b.
, 61b toward the pins 60a, 61a. In this way, the interval between the leads on the pins 60a and 61a side is widened, and the interval between the leads on the bonding portions 60b and 61b side is narrowed, so even if the inside of the frame 10 is narrow, the pin extraction efficiency is improved. good. Also, lead pin 60
, 61 have a trapezoidal cross-sectional shape as shown in FIG. Therefore, the bonding portions 60b and 61b of the lead pins 60 and 61 are connected to the second stepped portion 22, respectively.
are formed by insert molding on the horizontal surface 22h of the fourth stepped portion 24 and the horizontal surface 24h of the fourth stepped portion 24, but during manufacturing and wire bonding, those bonding portions 60b, 61
b is prevented from leaving the respective horizontal surfaces 22h and 24h.

(8) Detailed configuration of connection leads 62, 63, 64, 65 The connection lead 62 is made of a metal plate having the shape shown in FIG.
It is bent into the shape shown in the figure. In this connection lead 62, the pitch of each lead is wider on the side of the bonding part 62b than on the side of the bonding part 62a. This shape allows efficient electrical connection between the wiring patterns of the first circuit board 50, which has a narrow bonding space, and the second circuit board 52, which has a wide bonding space, without reducing the number of leads. can.

The connection lead 63 is made by bending the flat metal plate shown in FIG. 11 into the shape shown in FIG. 12, and the connection lead 64 is made by bending the flat metal plate shown in FIG. 13 into the shape shown in FIG. It is bent. Further, the connection lead 65 has a shape that is symmetrical to the connection lead 63. Using the connection leads 64 and 65 having this structure, the first circuit board 50 and the capacitors 56 and 57 installed in the capacitor box 15 formed in the frame 10 can be electrically connected.

The cross-sectional shape of the connection leads 62, 63, 64, and 65 is trapezoidal as shown in FIG. Therefore, the bonding parts 62a, 63a, 64a, 65a of the connection leads 62, 63, 64, 65 are formed on the horizontal surface 22h of the second stepped part 22 by insert molding, but they are The bonding portions 62a, 63a, 64a, and 65a are prevented from coming off the horizontal surface 22h. Similarly, the bonding parts 62b and 63b of the connection leads 62 and 63 are
It is formed on the horizontal surface 24h of the fourth stepped portion 24 by insert molding, but during manufacturing and wire bonding,
The bonding parts 62b and 63b are prevented from coming off the horizontal surface 24h.

(9) Structure of the back surface of the frame 10 The back surface of the frame 10 is structured as shown in FIG. 23. A groove 26 from which the end portion 62c of the connection lead 62 and the frame portion 62d protrude, and a groove 29 from which the end portion 63c of the connection lead 63 and the frame portion 63e protrude are formed. When the resin molding of the frame 10 with the connection leads 62 and 63 as inserts is completed, the frame portions 62d and 63e of the connection leads 62 and 63 are cut within the grooves 26 and 29, respectively.

Furthermore, an intermediate portion 62f (
Windows 27 and 28 are formed at a position corresponding to the intermediate portion 60d (see FIG. 8) connected to the bonding portion 60b of the lead pin 60, respectively. Among these, the window 27 is formed so that a support plate 66 for supporting the connection lead 62 in a mold without deformation or displacement during manufacturing, which will be described later, is placed. Also, window 27,
28 is used to confirm whether or not the connection leads 62 and the leads of the lead pins 60 are formed without contacting each other when the resin molding of the frame 10 is completed.

(10) Method for manufacturing electronic device 1 Frame 10
are lead pins 60, 61, connection leads 62, 63, 6
It is formed by resin molding using inserts 4 and 65. As shown in FIG. 24, the mold includes an upper mold 70, a lower mold 71,
It is mainly composed of a core (not shown). A cavity 72 for injecting resin is formed between the upper mold 70 and the lower mold 71. Lead pins 60, 61, 6
3, 64, and 65 are supported by a core for forming the connector box 14.

On the other hand, the connection lead 62 is arranged in the cavity 72 as follows. The tip portion 62c of the connection lead 62 and the frame portion 62d are inserted into the groove 68 formed in the lower mold 71, and the frame portion 62e is inserted into the upper mold 70 and the lower mold 7.
1, and the bonding part 62b is sandwiched between the upper mold 70 and the upper mold 70.
It is in contact with the cavity surface 72a of. An intermediate portion 62f following the bonding portion 62a and an intermediate portion 62g are arranged in a cavity 72, and the intermediate portion 62f is supported by a comb-shaped support plate 66 protruding from a groove 69 formed in the lower die 71.

The method of supporting the connection lead 62 by the support plate 66 is detailed in FIG. 25. Each foot 66 of the support plate 66
a is inserted into the gap between the leads of the connection leads 62, and each lead of the connection leads 62 is pressed toward the upper mold 70 by the root portion 66b of the support plate 66. As a result, the connection lead 62
The gaps between the leads are maintained appropriately, and the leads are prevented from coming into contact with each other during the resin molding process.

Furthermore, due to the pressing force f of the support plate 66 in the direction of the upper mold 70, the bonding parts 62a and 62b are pressed against the upper mold 70.
It receives a reaction force f directed toward the lower die 71 from the lower die 71 . As a result, the connection lead 62 is held in an appropriate posture within the cavity 72, and in the frame 10 after molding,
The bonding portions 62a and 62b of the connection lead 62 are exposed horizontally to the horizontal surface 22h of the second stepped portion 22 and the horizontal surface 24h of the fourth stepped portion 24, respectively,
Molding defects are prevented.

Furthermore, as shown in FIG. 26, the connection lead 620
If it is configured simply in a U-shape, its connection lead 6
20 does not have an intermediate portion (a portion corresponding to 62g in FIG. 24) extending in that direction at the position where the pressing force f by the support plate 66 acts, the bonding portion 620b where the pressing force f contacts the upper die 70. difficult to convey. Therefore,
The force for pressing the bonding part 620b against the upper mold 70 is insufficient, and a gap is created between the bonding part 620b and the upper mold 70. In this case, resin may be injected into the gap and the bonding portion 620b may not be exposed. Furthermore, the posture of the bonding part 620b is inappropriate,
The bonding portions 620b may not be formed at regular pitches.

However, by forming the connection lead 62 in the shape shown in FIGS. 16 and 25, the bonding portion 62b is connected to the horizontal surface 24 of the fourth stepped portion 24 of the frame 10.
h can be appropriately formed. Since it is sufficient that the pressing force f by the support plate 66 acts appropriately on the connection lead 62, the shape of the connection lead 62 and the pressing force f by the support plate 66 are
The relationship between the position and the position where it is applied may be as shown in FIG.

[0045] Also, after molding the frame 10, the lead pin 60
, 61, frame parts 60c, 61c, 62e, 62d, 63e, 63d of connection leads 62, 63, 64, 65
, 64c, are cut.

(11) How to connect the capacitor 56 to the connection lead 64 The terminal portion 64b of the connection lead 64 has a shape as shown in FIG. 28. This terminal portion 64b is a welding area 6 where the leads 56a and 56b of the capacitor 56 are electrically welded.
4d is formed, and the length of the welding area 64d in the axial direction (h-axis direction) is shorter than that in the width direction (d-axis direction) due to the notch 64f. With such a configuration, the welding area 6 of the leads 56a and 56b
By narrowing the contact area with respect to 4d, current concentration during electric welding can be increased. Also, since the leads 56a and 56b are passed through this notch 64f, the lead 56a
, 56b are prevented from shifting during positioning and welding. Moreover, it also maintains the gap between the leads 56a and 56b, so that short circuits will not occur even when the device is used in a place with strong vibrations. Moreover, the notch 64f and the leads 56a, 56
Since the vibration leads 56a and 5 are engaged with
6b to the welded portion is relaxed, and peeling of the joint portion is suppressed.

The welding area 64d and the notch 64f may have the shape shown in FIG. 29, and current concentration can be increased during electric welding. As shown in FIG. 28, by bending the lead 56a through the notch 64f as shown in FIG. 29(d), the lead 56a is positioned and prevented from shifting during welding. Similarly, even if this device is used in a place with strong vibrations, short circuits between the leads are prevented, and the transmission of vibration to the welded parts of the leads is alleviated, which prevents peeling of the joints. is suppressed. Furthermore, even when the electronic device 1 is installed in a place with strong vibrations such as the engine room of a car, providing such a notch 64f reduces the transmission of vibration to the terminal part 64b, and the electric welding part is prevented from peeling off.

[0048]

Effects of the Invention The present invention provides a frame body in which an inner wall is formed with a step-like stepped portion having a horizontal surface that contacts the peripheral portion of the wiring surface side of the circuit board and is bonded to the circuit board with an adhesive. The wiring surface of the circuit board is characterized in that dummy wiring is formed on the wiring surface of the circuit board by a circuit pattern wired inside at a minute distance from the inside boundary line of the contact area with the horizontal surface. Therefore, the excess adhesive pushed out from the adhesive interposed between the horizontal surface and the circuit board will be stored in the minute gap between the inner boundary line and the dummy wiring, and the adhesive will be removed from the dummy wiring. This prevents the liquid from flowing beyond the inside of the wiring surface of the circuit board. Therefore, it does not adversely affect the electronic circuits mounted on the substrate or adhere to the connection portions (bonding portions) on the substrate and cause connection failures. In addition, the occurrence of cracks and deterioration of the heat dissipation effect due to differences in thermal expansion coefficient and viscosity between the substrate and the adhesive are prevented. In another invention, since a notch is formed on the inner boundary line side of the horizontal surface of the stepped portion, excess adhesive when joining the horizontal surface and the substrate is stored in the space formed by the notch and the substrate. Does not leak outside. Therefore, there is an effect similar to that described above.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of an electronic device according to a specific embodiment of the present invention.

FIG. 2 is a perspective view showing a frame of the electronic device.

FIG. 3 is a perspective view showing a frame body with a first circuit board mounted thereon.

FIG. 4 is a perspective view showing a frame body with a second circuit board mounted thereon.

FIG. 5 is a sectional view showing the structure of the frame.

FIG. 6 is a plan view showing the first circuit board.

FIG. 7 is a plan view showing the planar shape of the lead pin before bending.

FIG. 8 is a perspective view showing the three-dimensional shape of the lead pin after bending.

FIG. 9 is a plan view showing the planar shape of another lead pin before bending.

FIG. 10 is a perspective view showing the three-dimensional shape of the lead pin after bending.

FIG. 11 is a plan view showing the planar shape of the connection lead before bending.

FIG. 12 is a perspective view showing the three-dimensional shape of the connection lead after bending.

FIG. 13 is a plan view showing the planar shape of another connection lead before bending.

FIG. 14 is a perspective view showing the three-dimensional shape of the connection lead after bending.

FIG. 15 is a plan view showing the planar shape of another connection lead before bending.

FIG. 16 is a perspective view showing the three-dimensional shape of the connection lead after bending.

FIG. 17 is a sectional view showing the detailed configuration of the first stepped portion.

FIG. 18 is a sectional view showing another configuration of the first stepped portion.

FIG. 19 is a sectional view showing the detailed configuration of the third stepped portion.

FIG. 20 is a plan view showing the configuration of a third stepped portion on which a metal plate is placed.

FIG. 21 is a sectional view showing the detailed configuration of the fifth stepped portion.

FIG. 22 is a cross-sectional view showing the cross-sectional structure of a lead.

FIG. 23 is a back view showing the concept of the back of the frame.

FIG. 24 is a cross-sectional view showing the relationship between a mold and a connection lead in a method of manufacturing a frame body.

FIG. 25 is a perspective view showing a method of supporting connection leads during manufacture of the frame.

FIG. 26 is a perspective view for explaining inappropriate support due to an inappropriate shape of the connection lead during manufacturing of the frame body.

FIG. 27 is a perspective view showing the relationship between other shapes of connection leads and their support methods when manufacturing the frame.

FIG. 28 is a perspective view showing the bonding relationship between the terminal portion of the connection lead and the lead.

FIG. 29 is a plan view showing another structure of the terminal portion of the connection lead.

[Explanation of symbols]

1...Electronic device 10...Frame body 11...Downward opening 1
2... Upper opening 13... Bottom surface 14... Connector case 15... Capacitor box 21... First stepped part 22... Second stepped part 23... Third stepped part 24... Fourth stepped part 25... Third stepped part Stepped portion 21h, 2 of 5
2h, 23h, 24h, 25h...Horizontal surface 21v, 22v
, 23v, 24v, 25v...Vertical surface 21b...Notch 2
3b, 23d...Groove 23e...Protrusion 25b...Groove 26, 29...Groove 27, 28...Window 40...Metal plate 4
3...Metal plate 43
a...Protrusion 46...Metal plate
50...First circuit board 52...Second circuit board
51...Power supply circuit 53...Control circuit
54...Dummy wiring 55...Concave portion 56, 57...Capacitor 58...
Integrated circuit 60...Lead pin 62...Lead pin 6
0a, 61a... Pin 60b, 61b... Bonding part 62, 63, 64
, 65... Connection lead 62a... Bonding part 62b... Bonding part 6
2f, 62g...middle part 63a, b, 64a, 65a
...Bonding parts 64b, 65b...Terminal part 66...Support plate 70...Upper die 71...Lower die 72...Cavity 81, 82, 83, 84...Bonding part

Claims (2)

[Claims] 1. An electronic device in which a circuit board on which an electronic circuit is mounted is disposed in a case, the electronic device having a horizontal surface that contacts a peripheral portion of the wiring surface side of the circuit board and is bonded to the circuit board with an adhesive. A stepped part has a frame body formed on an inner wall, and a stepped part is formed on the wiring surface of the circuit board at an inner side spaced apart from an inner boundary line of a contact area with the horizontal surface. An electronic device characterized in that dummy wiring is formed using a circuit pattern. 2. The electronic device according to claim 1, wherein a notch is formed on the inner boundary line side of the horizontal surface of the stepped portion.