JPH09321445A - Packaging structure of electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a package structure of an electronic component which does not cause complication of a structure, increase of a case height and complication of building operation in a package of a structure wherein a printed board whereon an electronic component is mounted is sealed by a case. SOLUTION: A package 10 provided with a metallic case 13 for sealing an upper space of a printed board for enclosing an containing an electronic component 11 on a printed board 12 whereon an electronic component is mounted has a conductor film 15 formed in a proper place of an upper surface end edge of a printed board and a backed piece 16 formed by backing a part in a lower part of a side wall of a metallic case corresponding to a conductor film to an inside direction of a side wall, and is electrically and mechanically connected and fixed to the conductor film 15 with a backed piece backed inside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a package having a structure in which a printed circuit board on which electronic parts are mounted is sealed with a case, and particularly, the structure is complicated, and the case height is increased.
The present invention relates to a package structure for electronic components that does not complicate assembly work.

[0002]

2. Description of the Related Art In an electronic circuit that requires temperature compensation, electromagnetic shielding, etc., such as an oscillation circuit using a piezoelectric device such as a crystal oscillator, a printed circuit board provided with the electronic circuit is placed in a shield case. It is performed by encapsulating, unitizing it, and incorporating it into a device body such as an electronic device or a communication device. FIGS. 6 (a) and 6 (b) are an external perspective view and a bottom perspective view of an example of a package of a conventional electronic component. The package 1 has an upper surface of a printed circuit board 3 having a wiring pattern and an electronic component 2 on its upper surface. In this package 1, a notch 3a is provided at the center of two opposing edges of a printed circuit board 3, and a case edge corresponding to the notch 3a is provided. A projecting piece 4a that fits into the cutout 3a is projected from the lower edge portion, and the case 4 is assembled to the printed circuit board 3 with the projecting piece 4a fitted into the cutout 3a. The case 4 is fixed to the printed circuit board 3 by solder 5 between the back side of the projecting piece 4a and the back surface of the printed circuit board in a state where the package is turned over as shown in (b). However, in this conventional example, since a part of the case projects on the back surface of the printed circuit board, the total height of the package becomes large, which is against the request for miniaturization, and after the package is turned upside down. Since it is necessary to connect the solder, there is a drawback that workability is deteriorated.

The package of FIG. 6 is of a type in which the L-shaped lead terminal 6 projects below the printed circuit board 3, but in addition to this, the pad-shaped lead terminal is planar along the bottom surface of the printed circuit board. Some are arranged in. But,
In this type, it is not possible to project the protrusion 4a from the case, so that it is necessary to fix the side wall of the case and the edge of the substrate with solder or an adhesive. However, it is difficult to secure the cost for soldering and the like, which causes problems such as an increase in size of the package and complicated assembly work. Further, in Japanese Unexamined Patent Publication No. 8-37421, a constant potential of the same area as the multilayer structure substrate is provided below the multilayer structure substrate on which a crystal oscillator and a plurality of circuit elements are mounted, through the multilayer structure substrate. A temperature-compensated crystal oscillator having a structure in which a shield layer 8 as a surface is provided is disclosed.
By providing the above-mentioned configuration, it is possible to omit the trouble of fine adjustment of the frequency when mounting on the board, and prevent the variation of the electrical characteristics such as the oscillation frequency, the frequency temperature characteristic, the consumption current, and the output voltage due to the adjustment. I have to. However, this conventional example has a drawback that not only is the substrate itself expensive because the substrate structure is complicated, but it is difficult to automate the process of mounting components in the recesses on the substrate.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and in a package having a structure in which a printed circuit board on which electronic components are mounted is sealed with a case, the structure is complicated and the case height is increased. It is an object of the present invention to provide a package structure for electronic components that does not complicate assembly work.

[0005]

In order to achieve the above object,
The invention according to claim 1 is a package including a metal case for enclosing and storing an electronic component on a printed circuit board on which the electronic component is mounted, the package including a metal case.
A conductor film formed at a proper position on the upper edge of the printed circuit board,
A withdrawal piece formed by withdrawing a portion corresponding to the conductor film below the side wall of the metal case toward the inner side of the side wall, and the conductor film with the withdrawal piece retracted inward. It is characterized in that it is electrically and mechanically connected and fixed. The invention of claim 2 is characterized in that the conductor film is connected to the ground of an electronic circuit on the printed circuit board. The invention of claim 3 is characterized in that the conductor film is formed by metallizing a surface of a base material made of a non-conductive material with a conductive metal. According to a fourth aspect of the invention, the metal case has a convex portion or a concave portion at a proper position on the lower end edge of the side wall thereof, and the concave portion or the convex portion is formed on the edge of the printed circuit board corresponding to the convex portion or the concave portion on the metal case side. Is provided, and each convex portion and each concave portion are fitted to each other. According to a fifth aspect of the present invention, the convex portions or the concave portions provided on the side wall of the metal case and the end edge of the printed circuit board are provided on the two side walls of the metal case facing each other and the two end edges of the printed circuit board facing each other. It is characterized in that the respective convex portions or concave portions are respectively provided and have an asymmetrical positional relationship. According to a sixth aspect of the present invention, a convex portion or a concave portion is provided in a central portion of one side wall of the metal case or one end edge of the printed circuit board, and the other side wall or the other end edge facing each other is provided. It is characterized in that two convex portions or concave portions are arranged at symmetrical positions with the other side wall or the central portion of the other end edge sandwiched therebetween. According to a seventh aspect of the present invention, a convex portion or a concave portion is provided at a central portion of one side wall of the metal case or one end edge of the printed circuit board, and the other side wall facing the other side edge or the other end edge. It is characterized in that one convex portion or concave portion is provided at the central position. According to an eighth aspect of the present invention, one convex portion or a concave portion is provided on one side wall of the metal case or one end edge of the printed circuit board at a non-central portion, and the other side wall facing the other side edge or the other end edge is formed. It is characterized in that one convex portion or concave portion is provided at a non-central position, which is opposed to the one convex portion or concave portion. According to a ninth aspect of the present invention, there is provided a package including a metal case that seals an upper space of the multilayer printed circuit board so as to surround and house the electronic component on the multilayer printed circuit board on which the electronic component is mounted. A groove formed by cutting out a proper place on the upper surfaces of the opposing edges of the printed circuit board so that a part of the grounding electrode film embedded inside is exposed, and the groove at the lower part of the side wall of the metal case. And a retracting piece formed by retracting a portion corresponding to the inward direction of the side wall, and the lower end of the retracting piece projects a predetermined length from the lower end edge of the side wall of the metal case. It is characterized in that it is electrically and mechanically connected and fixed to the electrode film exposed at the bottom of the groove while being retracted inward.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. 1 (a) and 1 (b) are an exploded perspective view of a package of an electronic component according to one embodiment of the present invention and a back view of a printed circuit board, and FIGS. 2 (a), (b) and (c) are assembled states. FIG. 4 is a perspective view showing a main part, an enlarged view of a main part, and an AA cross-sectional view. The package 10 includes a printed circuit board 12 on which an electronic component 11 is mounted, and a metal case 13 that encloses the electronic component 11 on the printed circuit board 12 and seals an upper space of the printed circuit board 12. . The characteristic structure of this package 10 is that the conductor film 15 is formed at appropriate positions on the upper edge of the printed circuit board 12 and that the lower portion of the side wall of the metal case 13 corresponding to the conductor film is free inward and outward. The point is that the retracting piece 16 is formed by forming a notch in the lower portion of the side wall. Then, when the retractable piece 16 is retracted to the inside of the metal case 13 at a predetermined angle and retracted, when the metal case 13 is placed on the printed circuit board, the tip of the retractable piece 16 contacts the conductor film 15. , Electrically and mechanically connected and fixed. This contact state may be elastic pressure contact or simple inelastic contact.

In FIG. 1, the conductor film 15 and the retracting piece 16 are provided at the central portions of the opposing short sides of the printed board 12 and the metal case 13, respectively, but this is an example, and these are the short sides or the long sides. It may be provided at any position on the side. The evacuation piece 16 shown in the figure is formed by bending the part formed by forming two cuts in the case side wall inward, but this is merely an example, and a part of the side wall is pressed. The retracting piece may be formed by denting the inside by. The conductor film 15 is formed, for example, by metallizing the base material of the printed board 12, that is, the surface of the non-conductive material, with a conductive metal. As the metal material to be used, for example, a silver-palladium film, a nickel film, and a gold film are sequentially stacked and plated. The silver-palladium film is used as the bottom layer film because it is easily compatible with the ceramic substrate, the gold film is used because it has good compatibility with the solder, and the nickel film eliminates the poor compatibility between the silver-palladium film and the gold film. For use as an intermediate film.

As a positioning method for attaching the metal case 13 to the printed circuit board 12, in this embodiment, a convex portion or a concave portion 20 is formed at an appropriate position on the lower end edge of the side wall of the metal case 13, and the convex portion or the concave portion on the case side is formed. Providing a concave portion or a convex portion 21 on the edge of the printed circuit board corresponding to the concave portion 20,
Each convex portion and each concave portion are fitted together. Positioning is completed by fitting one protrusion into the other recess. After the positioning is completed, by pouring solder between the outer surface of the retracting piece 16 retracted inward from the side wall of the metal case and the upper surface of the conductor film 15, the retracting piece 16 and the conductor film 15 are electrically and mechanically connected. Fixed to. In this connection work, electronic components on the board are temporarily fixed on the board in advance using cream solder, and a case is put on the board to put the cream solder between the retracting piece 16 and the conductor film 15. By heating the entire package after filling with, the electronic component and the case can be collectively reflow-connected on the substrate. Of course, the case may be connected and fixed on the substrate after the electronic component is fixed on the substrate.

Further, the conductor film 15 is connected to the ground of the electronic circuit on the printed circuit board if necessary. With this configuration, the metal case can exert the shielding effect. The case 13 may be made of ceramics or heat-resistant resin other than metallic materials. When a case other than a metal material is used and a shield effect is desired, the case surface may be metalized. Particularly, the portion of the retracting piece 16 that is in contact with the conductor film 15 needs to be processed to have a conductive surface by metallization or the like. Next, regarding the above-mentioned positioning of the convex portion or the concave portion for positioning, in FIGS. 1 (a) and (b), positioning is performed by providing the convex portion and the concave portion at the central portions of the side wall and the edge facing each other. However, with this configuration, it is likely that the front and rear directions of the case and the printed circuit board are erroneously assembled. In order to prevent such erroneous mounting, the projections or recesses 20 formed on the opposing side walls or the recesses or projections 21 formed on the opposing edges are made asymmetric. Their respective positions,
It is effective to change the number and the like. In the back view of the printed circuit board of FIG. 1 (b), reference numeral 22 is a pad used for surface mounting this package on another board, and 23 is a solder reservoir.

3 (a), (b) and (c) are schematic plan views showing a structural example for preventing erroneous mounting when mounting a metal case on a printed circuit board. First, (a) faces each other. 2 sides S1,
A convex portion or a concave portion 20 at the center of one side S1 of S2,
21 is provided at one place, and the other side S2 is connected to the side S2.
Two convex portions or concave portions 20 and 21 are arranged symmetrically with respect to the center C of the above. Two sides S facing each other like this
Since the convex portions or the concave portions 20 and 21 are arranged in the asymmetrical positional relationship and number on the S1 and S2, erroneous mounting can be prevented. Next, in the example of FIG. 3 (b), one convex portion or concave portion 20 or 21 is arranged at the center position of the other side S2, and the convex portion or concave portion 20 or 2 is formed at the non-center position of the one side S1.
By arranging 1, the positional relationship between the convex portions or the concave portions 20 and 21 on both sides S1 and S2 is made asymmetric to prevent erroneous mounting. In this example, the positions of the convex portions or the concave portions 20 and 21 on the side S2 are the non-center portions of the side S2,
You may provide in the position which becomes asymmetric. In the example of Fig. 3 (c),
Convex portion or concave portion 2 provided on both sides S1 and S1 respectively
By arranging 0 and 21 so as to face each other, erroneous mounting is prevented.

Next, FIG. 4 is an exploded perspective view of a package of another embodiment, and FIGS. 5 (a), (b), (c) and (d) are front sectional views showing the overall structure of the package of this embodiment. It is a side view, the block diagram of a case, and the structure of a printed circuit board. The feature of this embodiment is that a multilayer board is used as the printed board 12, and the upper surface of the facing edges of the multilayer board is cut into a groove having a predetermined depth so that it is embedded in the thickness of the board. An electrode film 25 for grounding having an area approximately equal to the substrate area
Partly exposed, and the exposed ground electrode film 25
In addition, the evacuation piece 16 protruding downward from the case 13 is electrically connected and fixed, and the case 13 is covered on the multilayer substrate 12. The retracting piece 16 provided in the case 13 of this embodiment projects downward by a predetermined length from the lower bottom edge of the case, and the protruding length of the retracting piece 16 in the downward direction is the case 13.
When the substrate is closed on the substrate, the tip of the retracting piece 16 is moved to the groove 26.
It is set so as to be in contact with the electrode film 25 on the bottom surface of the. With this configuration, each retreat piece 16 is provided with each groove 26 on the substrate.
Positioning of the case is completed by simply covering the substrate with the case 13 in such a positional relationship as to enter the inside, and fixing is completed by fixing the joint between the retracting piece 16 and the electrode film 25 in the groove with solder. To do. In this form example, the retracting piece 16
Since the groove 26 and the groove 26 can also serve as the positioning means, it is not necessary to specifically provide the positioning projections or recesses 20 and 21 as in the above embodiment. It should be noted that one or both of the grooves 26 and the retracting pieces 16 may be displaced from the illustrated center position by a predetermined distance so that the mounting direction of the case with respect to the substrate is not erroneous. Alternatively, it is preferable that both the grooves and the retracting pieces are arranged asymmetrically. In the above example,
Although one groove and one retreat piece are provided on each side, a plurality of grooves and retreat pieces may be provided as needed.

[0012]

As described above, according to the present invention, a part of the lower edge portion of the case does not project downward beyond the lower surface of the substrate, so that the height of the package can be kept low. Since it is sufficient to simply place the case on the board and then directly connect the solder without turning over the board at the time of solder connection, automatic mounting is easy. Since the case can be soldered to the board together with the electronic components on the board by reflow, the connection work can be realized in one step. Further, by providing the concave portion and the convex portion for positioning, the positioning of the case becomes easy. By arranging the concave portions and the convex portions for positioning in a non-symmetrical positional relationship and the number thereof, it is possible to prevent the case from being mounted in the wrong orientation with respect to the substrate. Further, when applied to a multi-layer substrate, the concave portion and the convex portion for positioning can be omitted to simplify the configuration and workability.

[Brief description of drawings]

1A and 1B are an exploded perspective view of a package of an electronic component according to an embodiment of the present invention, and a bottom configuration diagram of a printed circuit board.

2 (a), (b) and (c) are a perspective view showing an assembled state of the package of FIG. 1, an enlarged view of a main part and a sectional view taken along line AA.

3 (a), (b) and (c) are schematic plan views showing configuration examples for preventing erroneous mounting.

FIG. 4 is an exploded perspective view of a package according to another embodiment of the present invention.

5 (a), (b), (c) and (d) are a front sectional view, a side view, a configuration diagram of a case, and a configuration diagram of a printed circuit board showing the overall configuration of the package of the embodiment example of FIG.

6A and 6B are a perspective view and a bottom perspective view showing a configuration of a conventional package.

[Explanation of symbols]

10 package, 11 electronic component, 12 printed circuit board, 13 metal case, 15 conductor film, 16 retractable piece,
20 convex part or concave part, 21 concave part or convex part, 25 electrode film, 26 groove.

Claims (9)

[Claims] 1. A package provided with a metal case for sealing an upper space of a printed circuit board for enclosing and accommodating the electronic device mounted on the printed circuit board, the package being formed at a proper position on an upper edge of the printed circuit board. And a retractable piece formed by retracting a portion of the metal case corresponding to the conductive film below the side wall of the metal case toward the inside of the side wall, the retractable piece being retracted inward. 2. A package structure for an electronic component, which is electrically and mechanically connected and fixed to the conductor film. 2. The package structure for an electronic component according to claim 1, wherein the conductor film is connected to a ground of an electronic circuit on the printed board. 3. The package structure for an electronic component according to claim 1, wherein the conductor film is formed by metallizing a surface of a base material made of a non-conductive material with a conductive metal. 4. The metal case has a convex portion or a concave portion at an appropriate position on a lower end edge of a side wall thereof, and a concave portion or a convex portion is formed on an end edge of the printed circuit board corresponding to the convex portion or the concave portion on the metal case side. 4. The package structure for an electronic component according to claim 1, 2 or 3, wherein each convex portion and each concave portion are fitted to each other. 5. The convex portions or the concave portions provided on the side wall of the metal case and the end edge of the printed board, respectively, are provided on the two side walls of the metal case facing each other and the two end edges of the printed board facing each other, respectively. The package structure for an electronic component according to claim 4, wherein the respective convex portions or concave portions have an asymmetrical positional relationship. 6. A convex portion or a concave portion is provided in a central portion of one side wall of the metal case or one end edge of the printed board, and two opposing side walls or the other end edge are provided with two protrusions or recesses. 6. The package structure for an electronic component according to claim 4, wherein the convex portion or the concave portion is arranged symmetrically with the other side wall or the center portion of the other end edge sandwiched therebetween. 7. A convex portion or a concave portion is provided at a central portion of one side wall of the metal case or one end edge of the printed circuit board, and the other side wall facing the other or a non-central position of the other end edge. The package structure for an electronic component according to claim 4 or 5, characterized in that one convex portion or one concave portion is provided in the. 8. A convex portion or a concave portion is provided on a non-central portion of one side wall of the metal case or one end edge of the printed circuit board, and the other side wall opposite thereto or the non-center portion of the other end edge. 6. The package structure for an electronic component according to claim 4, wherein one convex portion or concave portion is provided at a position facing the one convex portion or concave portion. 9. A package including a metal case for sealing an upper space of a multilayer printed circuit board for enclosing and accommodating electronic components on the multilayer printed circuit board, wherein the inside of the multilayer printed circuit board is thick. A groove formed by notching appropriate places on the upper surfaces of the opposing edges of the printed circuit board so as to expose a part of the grounding electrode film buried in the groove, and corresponds to the groove at the lower side wall of the metal case. A retracting piece formed by retracting the portion to be retracted inward of the side wall, the lower end of the retracting piece projects a predetermined length from the lower edge of the side wall of the metal case, and the retracting piece is placed inside. A package structure for an electronic component, which is electrically and mechanically connected and fixed to the electrode film exposed at the bottom of the groove in a retracted state.