JP2598344B2 - Leadless package case for double-sided mounting board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leadless package case for accommodating a double-sided mounting board of an electronic device.

[0002]

2. Description of the Related Art With the miniaturization of electronic equipment, double-sided mounting for miniaturization of embedded electronic circuit components and improvement of packaging density has been put to practical use, and surface mounting technology (surface mount technology) by automatic machines has been introduced. Have been. On the other hand, as the transition from analog technology to digital technology progresses, logic noise interference due to electromagnetic coupling between close circuits cannot be ignored, and electromagnetic shielding is provided as necessary. 5 and 6 are perspective views showing a mounting structure of such a conventional functional circuit device. FIG. 5 shows a printed wiring board 51.
A circuit element 52, for example, a chip component is mounted on one surface of the device, and a metal shield case 55 is covered from above as shown by the arrow. Reference numeral 53 denotes an electronic electrode divided into through holes for circuit connection, and reference numeral 54 denotes an electronic electrode for soldering and fixing the stopper 56 of the shield case 55 to ground. After being assembled in this way, it is surface-mounted on the main circuit board.
The wiring conductors of the printed wiring board 51 are not shown. FIG. 6 shows an example in which a double-sided mounting board in which circuit elements 62 are mounted on both front and back surfaces of a printed wiring board 61 is assembled by shield. That is, electromagnetic shielding is performed by combining metal shield cases 64 and 65 from above and below a double-sided mounting board having circuit elements 62 mounted on both sides in the direction of the arrow. As described above, in the case of a double-sided mounting board, the shield case 65 is also arranged on the lower side (main circuit board side), so that the terminal pins 63 are required for circuit connection with the main circuit. It can be mounted manually because it cannot be mounted.

[0003]

As described above, the conventional functional circuit device has the following problems. (1) In the case of a single-sided mounting board, since the mounting density is low and a shield case is separately manufactured and attached,
It takes a long time to assemble, and is an obstacle to cost reduction. (2) In the case of a double-sided mounting board, two upper and lower shield cases are required, and material costs and assembling time for manufacturing separately are required, which not only hinders cost reduction but also prevents surface mounting on the main board. It is necessary to provide a through hole for inserting and connecting the terminal pins on the main board, which limits the cost reduction. The present invention seeks to solve the above problems,
It is an object of the present invention to provide a leadless package case that can accommodate a double-sided mounting substrate, has an electromagnetic shielding function, and can be surface-mounted on a main substrate.

[0004]

A leadless package case for a double-sided mounting board according to the present invention is formed in advance on the metal foil surface of a metal base multilayer wiring board in which a metal thin plate and a metal foil are laminated with an insulating film interposed therebetween. A rectangular box portion formed such that the metal thin plate serving as the electromagnetic shield plate is outside and the lower side is an opening surface, and the edges of the four sides of the opening surface of the box portion. And a bent portion formed so that a portion of the wiring conductor exposed to the lower tangent portion of the U-shape is outwardly bent in a U-shape and formed as a terminal portion when surface-mounted, and A plurality of projections are provided on a side wall surface of the box portion for fitting and fixing a double-sided mounting board to be accommodated in the box portion at a predetermined position.

[0005]

1 is a perspective view showing an embodiment of the present invention. FIG. 1 (A) is a perspective view from above, and FIG. 1 (B) is a perspective view when it is turned upside down. In the figure, 1 indicates a box part,
The outside is a metal surface for overall shielding. Reference numeral 2 denotes a bent portion at the open end. Reference numeral 3 denotes a small concave portion, which is a fixing stopper for the double-sided mounting substrate to be accommodated therein. 3a and 3b
A double-sided mounting board is fitted between the inner convex protrusions so as to be substantially parallel to the top surface of the box portion 1. Therefore, the rectangular shape of the top surface of the box portion 1 is made to have a size corresponding to the planar shape of the double-sided mounting substrate to be accommodated. Reference numeral 4 denotes a wiring conductor, which includes a circuit connection conductor 4a, a grounding conductor 4b, and an internal wiring conductor 4c. The circuit connecting conductor 4a and the grounding conductor 4b serve to connect to the terminal electrodes on the peripheral edge of the double-sided mounting board to be accommodated, and the opening of the main board in the state shown in FIG. It has a role of a connection terminal electrode (terminal portion) with a wiring electrode. Further, the grounding conductor 4b is connected to a metal surface on the outer surface of the box portion 1 at an end of the bent portion 2 bent in a U-shape.

FIG. 2 is a sectional view of an embodiment of the present invention, and FIG. 3 is a partially detailed sectional view for explaining members of the present invention. FIG. 3 shows a member used for the package case of the present invention, which is an enlarged view of a part of the box 1. This member is called a metal-based multilayer wiring board. As shown in FIG. 3, an insulating coating 12 such as a polyimide or an epoxy resin is applied to a thin metal plate 11 such as a nickel silver or the like, and a metal foil such as a copper foil is formed thereon. 13 are stacked. A desired wiring conductor 4 is formed by etching the surface of the metal foil 13 before three-dimensionally processing the metal-based multilayer wiring board. FIG. 2 shows a cross section of a package case in which the surface of the thin metal plate 11 of the metal-based multilayer wiring board is formed on the outer surface. The box-shaped structure is made by squeezing or bending. A circuit connection conductor 4a formed in advance is provided at the lower left bent portion, and insulation is maintained by a gap 5 at an end from the metal sheet 11 on the surface of the case. The reason why the circuit connection conductor 4a is provided continuously beyond the contact point with the opening surface below the bent portion to the outside is to ensure solder bonding and confirmation when surface-mounted on the main board. It is. In the lower right bent portion, a preformed grounding conductor 4b
The cutting portion at the tip is crushed during the cutting process and is in a conductive state with the metal sheet 11 on the surface of the case.

FIG. 4 is a sectional view showing an application example of the present invention, and shows a state in which a double-sided mounting board is housed inside. The double-sided mounting board having the circuit elements 7 mounted on both sides of the double-sided wiring board 6 is inserted from the opening of the package case of the present invention and fitted between the stoppers 3a and 3b. The electrodes of the double-sided wiring board 6 and the circuit connecting conductors 4a are connected by solder 9.

As an example for further improving the effect of the present invention, as shown by a broken line in FIG. It can be a heavy structure. Moreover,
It can be mounted in a shielded state.

[0009]

As described in detail above, by implementing the present invention, a double-sided mounting board can be mounted on a surface mounting device (SM).
Since D (Surface Mount Device) can be used, through-hole terminals are not required on the main substrate, and reflow soldering can be performed in the same manner as other square chip components, thereby significantly reducing the assembling time and cost. There is. In addition, since the surface portion of the device is completely electromagnetically shielded, malfunctions due to electromagnetic coupling of small non-devices can be completely prevented by providing a ground conductor on the entire surface or inner layer on the main board side. further,
In addition to the effects of thinning and miniaturization, a triple structure is possible, which has a remarkable effect on improving the mounting density of devices.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing one embodiment of the present invention.

FIG. 3 is a partially enlarged sectional view of the present invention.

FIG. 4 is a sectional view showing an application example of the present invention.

FIG. 5 is a perspective view showing a conventional structure example.

FIG. 6 is a perspective view showing a conventional structure example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Box shape 2 Folded part 3 Concave part 4 Wiring conductor 5 Gap 6 Double-sided wiring board 7, 8 Circuit element 9 Solder 11 Metal thin plate 12 Insulating coating 13 Metal foil 51, 61 Printed wiring board 52, 62 Circuit element 53, 54 Terminal electrode 54,56 Shield case 63 Terminal pin

Claims (1)

(57) [Claims] 1. A metal-based multilayer wiring board in which a metal thin plate and a metal foil are laminated with an insulating film interposed therebetween, wherein a metal conductor surface formed in advance on the metal foil surface becomes an electromagnetic shielding plate. A rectangular box portion formed such that the thin plate is on the outside and the lower side is an opening surface, and edges of four sides of the opening surface of the box portion are bent outward in a U-shape, and the U-shaped lower tangent line is formed. A bent portion formed so that a part of the wiring conductor exposed at the portion becomes a terminal portion when surface mounting is performed, and a double-sided mounting substrate to be housed in the box portion on a side wall surface of the box portion. A leadless package case for a double-sided mounting board provided with a plurality of protrusions for fitting and fixing at predetermined positions.