JPH09181472A - Shield structure of high frequency apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent shield tabs of a shield case from coming off, ensure a stable electrical connection and prevent a surface treated part from separating from the case, irrespective of the surface treatment thereof, by providing lips with pinching parts and claws of tab to hook the claws in holes of the case. SOLUTION: A shield tab 10 has lips 12 and 13 with J-shaped pinching parts 14 and 15 inside and inwards extended claws 16 and 17 formed by notching the lips. A hole 43 is cut into a partition plate 41 in a shield case 40 so that when the plate 41 is held with the tab 10 the claws 13 and 14 hook in the hole 43 enough to block the tab 10 from dropping. The case 40 holding the tab 10 is laid over a substrate 1 and electrically connected to an earth pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield structure for high frequency equipment.

[0002]

2. Description of the Related Art Conventionally, in a high frequency radio device, a metal plated shield case is installed on a substrate in order to obtain desired electrical characteristics. FIG. 3 is a schematic exploded perspective view showing an example in which a contact plate is attached between the substrate and the shield case in order to obtain the shielding effect more stably and surely.

In the figure, reference numeral 81 is a shield case, and the shield case 81 is formed by metal plating the entire surface of a resin plate. This shield case 81
Is provided with a partition portion 83 having a shape along the ground pattern 99 of the substrate 95 described below.

Reference numeral 87 is a contact plate made of a spring material, and is constituted by providing a claw 89 and a locking piece 91 on the upper side of the plate having a shape along the partition portion 83. The claw 89 is formed by bending the upper end side of the plate at a right angle and by bending both ends thereof upward, and the locking piece 91 is formed by bending the plate downward in a substantially U-shape.

On the other hand, 95 is a substrate, and various circuit blocks 97 such as a transmission block and a reception block are constructed by attaching various electronic parts (not shown) on the lower surface thereof. A ground pattern 99 is provided between the various circuit blocks 97.

The partition portion 83 of the shield case 81
The engagement piece 91 of the contact plate 87 is engaged and fixed to the contact plate 87, and the substrate 95 is covered and fixed thereon. As a result, the claw 89 of the contact plate 87 is pressed against the ground pattern 99 of the substrate 95,
There is a reliable connection between the two. As a result, the various circuit blocks 97 are shielded and electromagnetic interference is prevented.

[0007]

However, the above-mentioned shield structure has the following problems.

Since the surface of the shield case 81 is metal-plated, the engagement piece 91 of the contact plate 87 may be disengaged from the shield case 81 if the state of the surface treatment varies.

When the contact plate 87 is attached to the partition 83 of the shield case 81, the contact plate 87 is easily bent, and in this case, the positions of the claws 89 are varied. The contact plate 87 is not flexible to change the shape.

Various contact plates 87 are required and the die cost is expensive.

[0011]

In order to solve the above problems, the present invention provides a substrate provided with various circuit blocks 31 as shown in FIGS. 1 and 2 and with an earth pattern 33 separating the various circuit blocks 31. 30 and this substrate 30
A shield case 40 which is provided on the upper surface and has a partition plate 41 at a position facing the earth pattern 33; clamping portions 12 and 13 for clamping the partition plate 41; and the clamping portion 12,
And a shield tab 10 provided with a contact piece 21 standing upright from a bottom surface 11 for connecting 13 and biasingly contacting with the earth pattern 33. The pressure contact portions 14 and 15 bent in a circular shape and the claws 16 and 17 that extend inward by making a notch are provided, a hole 43 is formed in the partition plate 41 of the shield case 40, and the partition plate 41 is sandwiched between the shield tabs 10. At this time, the claws 16 and 17 are engaged with the hole 43 to prevent the shield tab 10 from coming off, and the shield tab 10 is placed on the substrate 30.
The shield case 40 sandwiching the above is covered, and the shield case 40 and the earth pattern 33 are electrically connected.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a shield structure according to the present invention, (a) is a schematic exploded perspective view of a shield tab and a shield case, (b) is a cross-sectional view of the shield case AA in a state of sandwiching the shield tab, and (c) is the same B. It is a -B sectional view. FIG. 2 is a schematic explanatory view showing a shield structure according to the present invention and showing a state in which a shield case for sandwiching a shield tab is covered on a substrate.

As shown in FIG. 1, the shield tab 10 is manufactured by processing a metal plate (stainless steel for springs plated with gold). A pair of sandwiching portions 12 and 13 are erected vertically at a substantially right angle, and the vicinity of the upper end is bent inward in a V shape to provide pressure contact portions 14 and 15 to improve the holding force. Further, the sandwiching portions 12 and 13 are formed with chevron-shaped notches, which are press-contact portions 14 and 1, respectively.
Claw 1 that entered almost straight along the surface of 5
6 and 17 are provided. Further, the bottom surface 11 is also notched and slightly bent to the outside, which is a contact piece 21 for biasing contact with the ground pattern 33 of the substrate 30.
Function as

As shown in FIG. 2, various circuit blocks 31 of a high frequency circuit such as a transmission block and a reception block are provided on the substrate 30, and the various circuit blocks 31 are separated by a ground pattern 33.

The shield case 40 is a resin-mold integrally molded product whose surface is silver-plated, and partition plates 41 are provided on the upper and lower surfaces thereof. As shown in FIG.
In the shield case 40, a partition plate similar to the partition plate 41 on the upper surface shown in the figure is formed on the back surface so as to match the shield pattern 33 of the substrate 30, and when covered on the substrate 30, various circuit blocks 31 on the substrate 30 are covered. Partition.

As shown in FIG. 1A, this partition plate 41
A rib 42 for attaching the shield tab 10 is provided on the inside of the rib 42. A hole 43 and a hole 44, which is formed at a right angle to the hole 43, is formed in the rear surface of the shield case 40. The hole 44 is a die-cutting mark for opening the hole 43 when the shield case 40 is integrally molded. The hole 43 is only for hooking the claws 16 and 17, and can be made small.
Has a diameter of φ1.5 mm or less to form the hole 43. When the holding portions 15 and 16 are fitted into the rib 42, the pressure contact portions 14 and 15
When it is pressed down with (FIG. 1 (b)) and is completely fitted, the claws 16 and 17 are caught in the hole 43 and the shield tab 10 cannot be removed (FIG. 1 (c)).

The shield case 40 having the shield tab 10 attached thereto is covered on the substrate 30. At this time, there is a contact piece 21 on the bottom surface 11 of the shield tab 10, and this contact piece 21 is pressed against the ground pattern 33 so that there is no contact failure. Without fail, conduction is ensured.

[0018]

As described in detail above, the shield structure for a high frequency device according to the present invention has the following excellent effects.

Since the press-contact portion and the claw are provided on the sandwiching portion so as to be hooked in the hole of the shield case and prevented from coming off, the shield tab can be surely prevented from falling off regardless of the surface treatment of the shield case. As a result, the surface treatment of the shield case does not peel off, and stable conduction can be secured.

Since the shield tab is sandwiched at the predetermined mounting position of the shield case, there is no variation in the contact position with the ground pattern, and stable conduction can be secured. Moreover, the automation of mounting is easy.

It is possible to flexibly deal with shield cases and substrates having different shapes. That is, it is not necessary to change the shape of the shield tab, and it is only necessary to change the attachment position.

There is no need for various types of shield tabs, and the die cost is low. As for the shield case, the cost can be improved by simply making a small hole in the conventional case.

[Brief description of the drawings]

FIG. 1 shows a shield structure according to the present invention, where (a) is a schematic exploded perspective view of a shield tab and a shield case, (b).
Is a cross-sectional view of the shield case AA in a state of sandwiching the shield tab, and (c) is a cross-sectional view of the same taken along the line BB.

FIG. 2 is a schematic explanatory view showing a shield structure according to the present invention and showing how a shield case holding a shield tab is covered on a substrate.

FIG. 3 is a schematic exploded perspective view showing a conventional shield structure.

[Explanation of symbols]

 10: Shield tab 11: Bottom surface 12, 13: Clamping part 14, 15: Press contact part 16, 17: Claw 21: Contact piece 30: Board 31: Various circuit blocks 33: Earth pattern 40: Shield case 41: Partition plate 43: Hole 81: Shield case 83: Partition 87: Contact plate 89: Claw 91: Locking piece 95: Board 97: Various circuit blocks 99: Earth pattern

Claims (1)

[Claims] 1. A substrate provided with various circuit blocks and an earth pattern for partitioning the various circuit blocks,
A shield case, which is placed on the substrate and has a partition plate at a position facing the earth pattern, a sandwiching part sandwiching the partition plate, and a bottom surface connecting the sandwiching part, which is erected and urgingly contacted with the earth pattern. And a shield tab provided with a contact piece for contacting the shield tab, and a sandwiching portion of the shield tab, a press-contact portion bent inwardly in a V shape, and a notch extending inward are provided to form a partition plate of the shield case. A hole is formed in the shield plate, and when the partition plate is sandwiched by the shield tab, the hole is clawed to prevent the shield tab from coming off, and the shield case is sandwiched on the substrate to cover the shield tab. A shield structure for high-frequency equipment, characterized in that the case and ground pattern are electrically connected.