Electricity: conductors and insulators – Anti-inductive structures – Conductor transposition
Patent
1988-02-11
1989-08-29
Nimmo, Morris H.
Electricity: conductors and insulators
Anti-inductive structures
Conductor transposition
29829, 29852, H05K 900, H05K 100, H05K 300
Patent
active
048619418
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a shielding device on a double-sided printed substrate on which a circuit for processing a high frequency signal such as a television tuner circuit, a receiver for a satellite broadcast, or the like is formed.
BACKGROUND ART
Recently, advances in packaging techniques have led to a substrate for mounting electronic components using ceramics rather than a substrate made from a member of the resin families. Generally, when a high frequency circuit including a UHF tuner, or the like is formed on a printed substrate, a shielding plate is erected (partition plate) to prevent interference and disturbance between individual circuit blocks. In this case, in the prior art, a plurality of legs are formed integrally with the shielding plate, and on the other hand, holes are formed in the printed substrate. The legs are inserted into the holes and soldered to a grounding conductor film on the back side of the printed substrate.
This technique will be described in detail with reference to FIGS. 1A and 1B. In FIGS. 1A and 1B, numeral 1 designates a substrate, 2 a grounding conductor film formed on the back side of the substrate 1, 3 a shielding plate, and 4 designates solder for connecting legs 3a of the shielding plate 3 to the grounding conductor film 2. Further, FIG. 1A is a cross section as viewed from the front side of the shielding plate, and FIG. 1B is a cross section as viewed from the side thereof.
Here, the substrate 1 is provided with rectangular holes for inserting therein the legs 3a of the shielding plate 3, and as shown in FIGS. 1A and 1B, the grounding conductor film 2 and the legs 3a are soldered to each other by passing the substrate 1 through a solder dipping vessel in a condition in which the legs 3a are inserted into the substrate 1.
However, in the arrangement mentioned above, it is necessary to form a multiplicity of rectangular holes in the substrate 1 for shielding therein the legs 3a of the shielding plate 3, and in particular, when a ceramic substrate is used as the substrate 1, a crack is apt to be caused in the substrate 1 from a portion of the corner of the rectangular hole due to a mechanical shock or a heat shock at the time of solder dipping. For example, as the rectangular hole, a hole of 1.5 mm+6 mm may be bored.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a shielding device which achieves a satisfactory shielding effect without damaging the substrate.
Another object of the present invention is to provide a shielding device in which the soldering of a shielding plate to a grounding conductor film can be performed much more reliably.
In a shielding device of the present invention, conductor films for grounding are formed respectively on one side and on the other side of a substrate, a penetrating hole (hereinafter referred to as a through-hole) is formed in the substrate, the conductor film on the one side is connected to the conductor film on the other side by a through-hole conductor disposed in this through-hole, no leg is provided on the shielding plate, a shielding plate is placed on the conductor film on the one side or on the other side, and the shielding plate is soldered to the conductor film on the one side or the other side. In this case, an opening portion of the through-hole is covered by a solder resist to prevent the solder from flowing out towards the other side passing through the through-hole, thereby to achieve reliable soldering to the conductor film on the one side or the other side of the shielding plate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B are respectively a front sectional view and a side sectional view of a principal part of a prior art shielding device,
FIGS. 2A and 1B are respectively a plan view, and a sectional view taken along the line 2B--2B, of a shielding device in one embodiment of the present invention,
FIGS. 3A and 3B are respectively a perspective view before soldering and a perspective view after soldering of a shielding plate of the shielding devic
REFERENCES:
patent: 4626963 (1986-12-01), Speer
patent: 4642735 (1987-02-01), Hodsdon et al.
patent: 4649461 (1987-03-01), Matsuta
patent: 4739453 (1988-04-01), Kurokawa
Kubo Kazuhiko
Nagai Hiroyuki
Saitou Susumu
Usui Akira
Matsushita Electric Industrial Co., Inc.
Nimmo Morris H.
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