JPH04296098A - Shield case - Google Patents

Abstract

PURPOSE:To enable a shield case to be enhanced in assembly workability, heat dissipating properties, and shielding effect. CONSTITUTION:An upper case 1 and a side wall board 15, and a lower case 8 and a side wall board 15 are formed into two pieces of integral structure for the formation of a shield case separable into an upper case 1 and a lower case 8. A heat dissipating plate 4 brought into electronic components by pressure is provided to the upper case 1 or a large number of small holes 3 are provided to the case 1 so as to enable silicone grease to be uniformly spread among electronic components to enhance the electronic components in heat dissipating properties. Earth terminal pins 16 are provided to the lower case 8 in one piece so as to be connected to the earth pins of another (main) board for the enhancement of a shield case of this design in shielding effect.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield case that has both leakage electromagnetic waves and a heat dissipation effect for a printed wiring board on which an element that generates significant heat, such as an integrated circuit element, is mounted.

0002

2. Description of the Related Art A conventional example is shown in FIG. 9. The shield case for the printed wiring board 11 on which the IC 13 with significant leakage of electromagnetic waves is mounted has a side case 22 attached to the side of the printed wiring board 11 and upper and lower lids 21 and 23, which are separate from each other. Side case 22 on wiring board 11
After the holder is attached, the upper and lower lids 21 and 23 are placed on top.

Furthermore, when the upper and lower lids 21 and 23 are covered after the side case 22 is attached to the side surface of the printed wiring board 11, a fixing protrusion 26 is provided on the side case 22 so that the upper and lower lids 21 and 23 are covered. The lids 21 and 23 are provided with elongated slit holes 25, and after they are fitted, the fixing projections 26 are bent and fixed.

[0004] Also, a printed wiring board 1 is attached to the shield case.
1, the printed wiring board 11 must be inserted from the side of the case 22. For this purpose, a guide groove 24 is provided in the side case 22. In addition, the side case 22 has a board guide 2 for soldering to ensure electrical contact between the shield case and the GND pattern of the board.
7 is provided, and has a structure that also serves as a guide for the board.

Furthermore, the side case 22 attached to the side surface of the printed wiring board 11 and the upper and lower lids 21 and 23 are separate;
2, perform soldering work near the board guide 27 to ensure electrical contact between the shield case and the GND pattern of the board, and then cover the upper and lower lids 21 and 23. There is. Conventionally, soldering work near the board guide 27 for ensuring electrical contact between the shield case and the GND pattern of the board has been done manually.

[0006] Regarding heat dissipation, the printed wiring board 11
In order to dissipate heat from the IC 13 mounted above, which generates a lot of heat, the IC 13 which generates a lot of heat is brought into contact with the shield case, and the heat is dissipated to the shield case, as shown in Fig. 9. In the conventional shield case, a U-shaped notch is made in the top cover 21 to form the heat transfer plate 28, and the heat transfer plate 28 is bent with only one side left to ensure contact with the IC 13. .

[0007]

However, the above configuration has the following problems. SUMMARY OF THE INVENTION An object of the present invention is to provide a shield case that can be easily attached to a printed wiring board on which an IC that leaks electromagnetic waves and generates significant heat is mounted, and can also ensure heat dissipation.

The side case 22 attached to the side surface of the printed wiring board 11 and the upper and lower lids 21 and 23 are separate from each other.
2 is installed, the upper and lower lids 21 and 23 are placed over the top and bottom lids 21 and 23, so the work required to attach the side case 22 to the side of the printed wiring board 11 and the long thin slit provided in the lid is required. Lower the upper and lower lids 2 so that the fixing protrusions 26 provided on the side case 22 fit into the holes 25.
1 and 23, there was a problem in that there was an operation to fix the lid by twisting the fixing protrusion 26 provided on the side case 22.

[0009] Furthermore, there was a problem in that it was necessary to perform soldering work near the board guide 27 in order to ensure electrical contact between the shield case and the GND pattern of the board before putting the lid on. .

[0010] Furthermore, it is difficult to automate the soldering work near the board guide 27 before putting the lid on.
There was a problem that the equipment cost for automation was high or the production takt time was long.

[0011] Also, a printed wiring board 1 is attached to the shield case.
1 from the side of the case, cover the lid, and then
G of the side case 22 of the card case and the printed wiring board 11
When soldering from the outside of the shield case to ensure electrical contact with the ND pattern, the reinforcing ribs 29 provided on the lid are also soldered at the same time.
There was a problem in that it became difficult to open the lid later due to maintenance or the like.

[0012] Also, a printed wiring board 1 is attached to the shield case.
1 from the side of the case, cover the lid, and then
During the soldering work to ensure electrical contact between the shield case and the GND pattern of the printed wiring board 11, connect the inside of the case and the GND pattern of the printed wiring board 11 from the outside of the shield case. Since the soldering work cannot be performed or is done manually, there is a problem that it is not possible to completely automate the assembly of the shield case by dipping or the like.

In order to radiate heat from the IC 13 mounted on the printed wiring board 11 that generates a lot of heat, the IC 13 that generates a lot of heat is
13 and the upper lid 21 to dissipate heat to the shield case, in the conventional shield case, a heat conductive sheet is attached to improve the heat transfer efficiency. Adhesive was applied to the back side of the wafer, but there were problems in that it required additional steps to supply the thermally conductive sheet and apply the adhesive, and it was difficult to automate the process of applying the relatively high viscosity adhesive. .

In order to radiate heat from the IC 13 mounted on the printed wiring board 11, which generates a lot of heat, the upper lid 21 and the IC 1
It has also been proposed to interpose silicone grease between the upper surface of the IC 13 and the upper surface of the IC 13, but there is a problem in that it is impossible to confirm whether it is spread evenly over the upper surface of the IC 13.

In order to radiate heat from the IC 13 mounted on the printed wiring board 11 that generates a lot of heat, the IC 13 that generates a lot of heat is
13 and the heat transfer plate 28 provided on the upper lid 21 to release heat to the upper lid 21, the conventional shield cable is used.
In this case, a U-shaped notch is made and only one side is left and bent to ensure contact with the heat-generating IC13, so it cannot be said that the structure is capable of vertical movement. Therefore, there was a problem that variations in the height of the IC could not be absorbed.

After attaching the shield case to the printed wiring board 11, when mounting these unit parts on the main board, the ground of the shield case itself is connected to the GND pattern of the printed wiring board 11. The shield case itself is not designed to be dropped directly to the GND of the main board, so it cannot be completely grounded, and the structure is not reinforced. There was a problem with the top being weak.

An object of the present invention is to provide a shield case that can be easily attached to a printed wiring board on which an IC that leaks electromagnetic waves and generates significant heat is mounted, and can also ensure heat dissipation. be.

[0018]

[Means for Solving the Problems] In order to solve the above problems, the shield case for a printed wiring board according to the present invention has the following features.

[0019] The upper case and the side wall plate, and the lower case and the side wall plate are each integrally constructed, and are separated into two cases.

A protrusion is provided on the upper case, and a fitting hole is provided on the side wall plate of the lower case, so that when the upper case 1 is placed over the lower case 8, The structure is such that the upper and lower cases can be connected and fixed using the protrusions 10.

[0021] When attaching the lower case to the printed wiring board, a groove is provided in the printed wiring board and the groove is fitted into the side wall plate of the lower case, so that it can be fixed to the printed wiring board. thing.

After attaching the upper case to the lower case,
When performing soldering work to ensure electrical contact between the shield case and the GND pattern of the board, use a soldering iron to the side wall plate of each of the upper and lower cases. The structure shall have a cutout that allows for the insertion of such items.

When performing soldering work from the outside of the shield case, there are four locations on the left, right, top and bottom of the connection area between the side wall plates of the upper case and the lower case and corresponding to the folded part. , fold some of the notches in the corners of the side wall panels inward,
The structure must be such that it can be soldered by dip.

In order to dissipate heat from an IC mounted on a printed wiring board that generates a lot of heat, when silicone grease is interposed between the shield case and the top surface of the IC that generates a lot of heat, the small hole is placed on the upper side. It is installed at the center and four corners of the IC, which generates a lot of heat on the top plate of the case, so that it can be confirmed that the silicone grease is spread evenly over the top surface of the IC, which generates a lot of heat. It has a structure.

In order to dissipate heat from an IC mounted on a printed wiring board that generates a lot of heat, when the IC that generates a lot of heat is brought into contact with the upper case and the heat is released to the upper case, the upper case A shield case having a structure in which a Z-shaped heat dissipation plate is provided with alternating cutouts on the top plate to enable vertical movement.

[0026] When installing a shield case in order to shield a printed wiring board on which electronic components with significant leakage of electromagnetic waves are mounted, the printed wiring board is fitted into the lower case and the upper case is attached. When fixing by pressing down from above, force is applied to the printed wiring board. This shield case has a structure in which a resin support post is provided near the center of the lower case to prevent the printed wiring board from bending.

[0027] When attaching the upper case and lower case to the printed wiring board in order to shield the printed wiring board on which electronic components with significant leakage of electromagnetic waves are mounted, the top plate of the upper case is By making a notch and raising the notch to create a leaf spring, the leaf spring installed in the upper case exerts a force that pushes the printed wiring board downward, thereby reducing the warpage of the printed wiring board and the height of the IC. A shield case with a structure that can accommodate variations.

[0028] When installing a unit component, which is a printed wiring board on which electronic components with significant leakage of electromagnetic waves are mounted, mounted on a shield case, to the main board, the GND and the shield case itself are directly electrically connected. So that you can connect
Make a notch in a part of the shield case, raise the notch in that part, and attach the ground terminal pin 16 near the connector side.
A shield case with a structure.

[0029]

[Function] Shield case for printed wiring board according to the present invention
This has the following effects:

[0030] Since the upper case and the side wall plate and the lower case and the side wall plate are integrated, the number of parts can be reduced, and the printed wiring board and the upper case or the lower case can be integrated. - It is possible to reliably maintain electrical contact with the base.

By providing the projection on the upper case and the fitting hole on the lower case, the case can be easily fixed and automated. Additionally, the upper case can be easily removed for later repairs.

By providing the printed wiring board with a dedicated groove for fixing the board, the printed wiring board can be attached from above when attached to the lower case 8, and automation can be achieved.

By exposing the printed wiring board at the corner of the case and bending the side wall plate of the shield case inward, the conventional manual work can be automated by dip soldering.

Although the ICs mounted on the printed wiring board have variations in height, the height variations can be absorbed by providing a leaf spring in the upper case.

[0035] On the top plate of the upper case, a Z-shaped heat dissipation plate with alternating notches that allows vertical movement is used to prevent warping of the printed wiring board and unevenness in the height of the IC. can be followed.

In order to dissipate the heat of an IC mounted on the printed wiring board 11 that generates a lot of heat, if silicone grease is interposed between the upper case and the top surface of the IC that generates a lot of heat, the small hole is inserted into the upper case. - By providing the silicone grease on the top plate of the grease, it can be confirmed whether or not the silicone grease is evenly spread over the top surface of the IC where heat generation is significant.

By providing a support post made of resin near the center of the lower case, the printed wiring board will not bend even when the upper case is closed.

By providing a ground terminal pin near the connector side, the ground can be connected directly to the GND pattern on the main board.
can be used.

[0039]

[Embodiments] Examples of the present invention will be described below with reference to FIGS. 1 to 8.

Embodiment 1 As shown in FIG. 1, the upper case 1 and the side wall plate 15 and the lower case 8 and the side wall plate 15 are integrally constructed to form a vertically separated shield case structure. did. Upper case 1 and side wall plate 1
5 or lower case 8 and side wall plate 15 in an integrated structure, cut the hoop material with a progressive die,
It is manufactured by bending the side wall plate 15 in a mold. The concave portion 7 of the upper case 1 is manufactured by drawing in a mold.

When attaching the shield case to the printed wiring board, as shown in FIG. 4, the printed wiring board 11 is fitted into the lower case 8 from above, and the upper case 1 is covered. At this time, by providing a groove 12 in the printed wiring board 11 and inserting the side wall plate 15 of the upper case 1 into this groove 12, the printed wiring board 11 is inserted into the lower case so that the printed wiring board 11 does not shift. Fixed at 8.

Further, as shown in FIG. 3, a protrusion 10 is provided on the side wall plate 15 of the upper case 1 and
A fitting hole 9 is provided in each of the holes 9 so that when the printed wiring board 11 is fitted into the lower case 8 from above and the upper case 1 is covered, the protrusion 10 fits into the fitting hole 9 and is fixed. did.

[0043] With the shield case structure as described above,
The work of attaching the shield case to the printed wiring board can be automated from the conventional manual work. Furthermore, maintenance efficiency can be improved when the lid is opened later for repairs. In addition, compared to a shield case structure in which the upper and lower lids are all integrated, it is possible to eliminate wasted material removal from the hoop material, and it is possible to process everything with a progressive mold. The productivity of the shield case can be improved and it can be manufactured at low cost.

Embodiment 2 When attaching a shield case to a printed wiring board 11 on which electronic components such as ICs with significant leakage of electromagnetic waves are mounted, the GND pattern of the printed wiring board 11 and the shield case body are electrically connected. connection is required. As shown in Figure 1,
Even after fitting the printed wiring board 11 into the lower case 8 from above and covering it with the upper case 1, the G of the printed wiring board 11
In order to electrically connect the ND pattern to the upper case 1 and the lower case 8, cutouts 2 are formed at the corners of the upper case 1 and the lower case 8, respectively. , and the printed wiring board 11 is partially exposed.
I made it into an old case. At the notch 2 as shown in FIG. 1, a part of the case was bent inward to provide a folding plate 17. The folding plate 17 of the lower case 8 also has the function of fixing the printed wiring board 11 at the same time. The folding plate 17 can prevent solder from penetrating into the inside of the shield case when soldering by dipping or the like, thereby making it possible to automate the soldering work. By making the shield case such a structure,
This eliminated assembly restrictions and improved production efficiency.

Embodiment 3 When attaching a shield case to a printed wiring board 11 on which electronic components such as ICs that leak electromagnetic waves and generate significant heat are mounted,
It is necessary to reinforce the printed wiring board 11 itself against warping and bending. As shown in FIG. 1, a support post 6 is provided at the center of the lower case 8 in order to reinforce the printed wiring board 11 against bending. When the printed wiring board 11 is fitted into the lower case 8 from above and the upper case 1 is covered, if force is applied to the printed wiring board 11 from above, the central part of the lower case 8 A support post 6 provided at the center prevents deformation of the central portion of the printed wiring board 11.

Furthermore, in order to prevent warpage of the printed wiring board 11 itself, as shown in FIG. There is. When the printed wiring board 11 is fitted into the lower case 8 from above and the upper case 1 is covered, the leaf spring 5 provided on the upper case 1 is inserted into the printed wiring board as shown in FIG. By the action of pressing down 11, printed wiring board 1
Even if the folding plate of the lower case 8 is separated from the bending plate of the lower case 8 due to the warpage of the folding plate 1 itself, it can be accommodated.

With the structure of the shield case as described above, the reliability of the printed wiring board 11 can be improved when the shield case is attached to the printed wiring board 11, and the reliability of the printed wiring board 11 can be improved. GND of wiring board 11
The reliability of the electrical connection between the pattern and the shield case can be improved.

Embodiment 4 When attaching a shield case to a printed wiring board 11 on which electronic components such as ICs, which leak electromagnetic waves and generate significant heat, are mounted,
It is necessary to electrically connect the GND pattern of the shield case body and the main board. The shield case is electrically connected to the GND pattern of the printed wiring board 11, but in order to more completely suppress unnecessary radiation leaking to the outside, it is necessary to connect the shield case body to the main board. An effective method is to reduce the voltage to the GND pattern of In the conventional shield case, the GND pattern of the printed wiring board 11 is connected to the GND pattern of the main board. In such a method, noise from the printed wiring board 11 may be transferred to the GND pattern of the main board, reducing the shielding effect by half. Therefore, as shown in FIG. 1, in the upper case 1 and the lower case 8, a part of the side wall plate 15 on the connector side is cut and turned down.
A ground terminal pin 16 is provided. After attaching the shield case to the printed wiring board 11 and assembling it, when inserting it into the connector on the main board, insert the ground terminal pin 16 into the hole on the main board as well to connect the shield case body and the main board. It can be electrically connected to the GND pattern of the substrate. Ground terminal pin 16 on shield case
By providing the main board and placing the shield case body on the GND pattern of the main board, unnecessary radiation leaking to the outside can be suppressed more completely.

Embodiment 5 When attaching a shield case to a printed wiring board 11 on which electronic components such as ICs, which leak electromagnetic waves and generate significant heat, are mounted,
It is necessary to dissipate heat from the IC 13, which generates significant heat. In Figure 9, heat from an IC that generates a lot of heat is transferred to the shield case.
In the conventional heat dissipation method of lowering the surface temperature of C,
A thermally conductive sheet 30 was inserted between the top lid 21 of the shield case and the IC 13 that generated significant heat, or the heat transfer plate 28 provided on the top lid 21 was pressed against the IC 13 that generated significant heat. However, there is work involved in supplying the thermally conductive sheet 30 and attaching it to the IC 13, which generates significant heat. In addition, since the heat transfer plate 28 does not have a mechanism to slide up and down,
It may not be possible to follow variations in the height of C, warpage of the printed wiring board 11, etc., and the contact between the IC 13, which generates a lot of heat, and the heat transfer plate 28 is insufficient, making it difficult to efficiently transfer the heat generated from the IC. - There is a possibility that it will not be possible to convey the information to the real case. In order to solve this problem, in FIG. 8, silicone grease 14 is inserted between the upper case 1 and the IC 13, which generates a lot of heat, so that heat can be efficiently transferred to the shield case. Become. Since the silicone grease 14 is a liquid with high viscosity, it can be absorbed even if there are height variations in the IC. Also, silicone grease
Since the sheet 14 has a very high thermal conductivity and is a material that conducts heat well, it has the same effect as the thermally conductive sheet 30. To check whether the silicone grease 14 is evenly spread over the top surface of the IC 13 that generates a lot of heat when applying the silicone grease 14 to the top surface of the IC 13 that generates a lot of heat and covers the upper case 1. As shown in FIG. 2, in the upper case 1, five small holes 3 are provided in positions corresponding to above the IC 13, which generates a lot of heat, so that the silicone grease 14 slightly protrudes from the small holes 3. Create a structure. If the silicone grease 14 protrudes slightly from the small holes 3 and is not spread evenly, the silicone grease will not come out of the small holes where the distance between the IC and the case is large among the five holes. Further, since it is easy to distinguish between the silicone grease 14 and the upper case 1, it is possible to automate confirmation of whether the silicone grease 14 has been applied uniformly.

Example 6 When attaching a shield case to a printed wiring board 11 on which electronic components such as ICs that leak electromagnetic waves and generate significant heat are mounted,
It is necessary to dissipate heat from the IC 13, which generates significant heat. In Figure 9, heat from an IC that generates a lot of heat is transferred to the shield case.
In the conventional heat dissipation method of lowering the surface temperature of C,
A thermally conductive sheet 30 was inserted between the top lid 21 of the shield case and the IC 13 that generated significant heat, or the heat transfer plate 28 provided on the top lid 21 was pressed against the IC 13 that generated significant heat. However, there is work involved in supplying the thermally conductive sheet 30 and attaching it to the IC 13, which generates significant heat. In addition, since the heat transfer plate 28 does not have a mechanism to slide up and down,
This may result in an inability to follow variations in the height of C, warpage of the printed wiring board 11, etc., and insufficient contact between the IC 13, which generates a lot of heat, and the heat transfer plate 28, making it difficult to efficiently dissipate the heat generated from the IC. There is a possibility that the information cannot be transmitted to the shield case. In order to solve this problem, as shown in FIG. 6, a heat dissipation plate 4 that can be slid up and down is provided on the upper case 1. A cut as shown in FIG. 7 is made in the upper case 1 at a position corresponding to the upper part of the IC 13, which generates a lot of heat, to form a heat dissipation plate 4, which is dropped downward to dissipate the heat. By bringing it into contact with the upper surface of the IC 13, heat can be efficiently transferred to the shield case. By making the cuts alternately as shown in FIG. 7, the heat dissipation plate 4 having the shape shown in FIG. 6 can be formed and can be slid up and down. Such cuts can be made simultaneously using a progressive die. Moreover, the heat dissipation plate 4, which can be slid up and down, can follow variations in the height of the IC, warpage of the printed wiring board 11, etc., and can ensure reliability of the heat dissipation effect.

[0051]

Effects of the Invention As described above, the shield case according to the present invention is more effective than the shield of a printed wiring board on which electronic components that leak electromagnetic waves and generate significant heat are mounted. It maintains proper contact, reduces the number of parts, can be automated, improves the reliability of the contact between the IC and the shield case, increases the heat dissipation effect, and also allows you to open the lid again after attaching it. This greatly helps in improving maintainability and lowering manufacturing costs.

[Brief explanation of drawings]

[Fig. 1] An exploded perspective view of a shield case according to an embodiment of the present invention.

[Fig. 2] A top view of essential parts of a shield case according to an embodiment of the present invention.

[Figure 3] Cross-sectional view of the shield case seen from the front

[Figure 4
] Exploded perspective view of printed wiring board and lower case

[Figure 5] Cross-sectional view showing the method of fixing the printed wiring board seen from the front

[Figure 6] Cross-sectional view showing the contact state between the IC and the shield case seen from the front

[Figure 7] Plan view of heat dissipation plate part

[Figure 8] Cross-sectional view showing contact between IC and shield case using silicone grease

[Fig. 9] Exploded perspective view of a conventional shield case

[Explanation of symbols]

1 Upper case 2 Notch 3 Small hole 4 Heat dissipation plate 5. Leaf spring 6 Support post 7 Recessed part 8 Lower case 9 Fitting hole 10 Protrusion 11 Printed wiring board 12 groove 13. IC that generates heat 14 Silicone grease 15 Side wall plate 16 Ground terminal pin 17 Folding board

Claims (9)

[Claims] [Claim 1] A shielding case for shielding a printed wiring board on which electronic components with significant leakage of electromagnetic waves are mounted.
It is a system in which the side wall plate and the upper case are integrated, and the side wall plate and the lower case are each integrated, and the structure is separated into two parts, the upper case part and the lower case part. -Rudo case. [Claim 2] A shielding case for shielding a printed wiring board on which electronic components with significant leakage of electromagnetic waves are mounted.
with respect to the groove provided in the printed wiring board.
2. The shield case according to claim 1, wherein the lower case is provided with a side wall plate which can be fitted into a groove provided in the printed wiring board to fix the printed wiring board. [Claim 3] A structure in which a notch is made in the upper case and a leaf spring is provided by raising the notch, and the printed wiring board is pushed downward by the leaf spring provided in the upper case. 1. The shield case described in 1. 4. The shield case according to claim 1, wherein the corner portion of at least one of the cases is bent inward to expose the printed wiring board. Claim 5: A structure in which the side wall plate and the bottom plate near the soldering protrusion provided on the side wall plate of at least one of the cases have a notch into which a soldering iron or the like can be inserted. A shield case according to claim 1. 6. In a shield case for shielding a printed wiring board on which electronic components are mounted which leak significant electromagnetic waves, silicone grease is applied between the upper case and the top surface of the electronic components. A system is constructed in which a plurality of small holes are scattered in the upper case, and when the upper case is set on a printed wiring board and pressed down, silicone grease protrudes from the small holes. -Rudo case. 7. A shield case in which a support post is provided near the center of the lower case, and the printed wiring board is supported by the support post so as not to bend. 8. The shield case according to claim 1, wherein cutouts are provided alternately in the upper case to provide heat dissipation plates that can be moved up and down. 9. A structure according to claim 1, wherein a ground terminal pin is integrally provided in at least one of the cases so that an electrical connection can be made to a ground portion of another board via the ground terminal pin. shield case.