Shielded case, electronic device having shielded case,...

Details Shielded case, electronic device having shielded case,... Shielded case, electronic device having shielded case,...

2001-07-10

2003-09-30

Martin, David (Department: 2841)

Electricity: electrical systems and devices

Housing or mounting assemblies with diverse electrical...

For electronic systems and devices

C361S800000, C361S818000, C361S745000, C174S034000

Reexamination Certificate

active

06628530

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to shielded cases designed to inhibit the transmission of electromagnetic waves, electronic devices using the shielded cases, electronic apparatuses using the electronic devices, and methods for manufacturing the shielded cases.
2. Description of the Related Art
FIG. 10
is a perspective view of a known shielded case
10
disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2-52481.
Shielded case
10
is made of a metal or an insulative material coated with a metallic film and includes a top wall
12
, a front wall
14
, a rear wall
16
and a pair of side walls
18
and
20
. The bottom
22
of the shielded case
10
is designed to be mounted on a circuit board and is open.
Shielded case
10
is formed by cutting a blank
24
(
FIG. 3
) having a predetermined shape from a single sheet of material and bending the sheet at substantially right angles along the dashed lines of FIG.
3
to form the walls
12
-
20
. The two side walls
18
,
20
are formed by half walls
18
a,
18
, and
20
a,
20
b,
respectively. Each of the half walls extends from and is integral with a respective edge of the front or rear walls
14
,
16
.
Mating parts
18
c
and
18
d
are formed in the half walls
18
a
and
18
b
, respectively, and interlock with each other when assembled to form the side wall
18
. Similarly, mating parts
20
c
and
20
d
are formed in the half walls
20
a
and
20
b
and interlock with when assembled to form the side wall
20
. The half walls
18
a
and
18
b
are butt-jointed at their respective edges in such a manner that the mating parts
18
c
and
18
d
couple with each other. Similarly, the half walls
20
a
,
20
b
are butt-jointed at their respective edges in such a manner that the mating parts
20
c
and
20
d
couple with each other.
An electronic element (e.g., an oscillation circuit) which is likely to be affected by electromagnetic waves is typically housed in the shielded case to protect it from externally generated electromagnetic waves and to contain electromagnetic waves generated by the electronic element with the case.
Various types of electronic devices can be shielded using the foregoing shield. One such class of devices are sensors for determining the movement of an object (e.g., an oscillation gyro). Such sensors are subject to strong impacts which threaten the integrity of the shielded case.
The two mating pairs of half walls of the known shielded case
10
are held together by the interlocking relationship between the mating parts
18
c
,
18
d
and
20
c
,
20
d
, respectively. Because these mating parts only interlock with one another, there is a risk that they will separate when an external impact is applied to the shielded case. If this happens, a gap will be formed between the mating parts and the electronic element in the case will not be sufficiently shielded from electromagnetic waves.
One way to avoid this problem is to apply solder to the mating parts to more firmly couple them together. However, this requires an additional manufacturing step and creates a problem of environmental pollution because of the lead in the solder.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a shielded case in which the mating parts do not separate from each other even when an impact is applied to the shielded case.
It is another object of the present invention to provide a shielded case in which mating parts are not likely to separate from each other and in which gaps between the mating parts can be reduced without the use of solder.
To these ends, according to a first aspect of the present invention, a shielded case comprises:
a plurality of walls, at least one of the walls being formed by at least first and second separate sections which abut one another along an interface; and
one or more depressions formed in at least one of the first and second sections so as to cause at least one of said sections to expand toward the other of said sections thereby pressure-welding said first and second sections along at least part of said interface.
In the shielded case according to the present invention, half walls are firmly coupled with each other by forming depressions in the half walls, whereby the half walls are not likely to separate from each other when an impact is applied.
In the shielded case according to the present invention, the half walls can be firmly coupled with each other without using solder, whereby a product free from lead can be provided.
In the shielded case according to the present invention, the half walls are coupled with each other without gaps therebetween, whereby electromagnetic waves inside can be prevented from leaking to the outside and the outside electronic waves can be reliably shielded.
The present invention is also directed towards a shielded electronic device comprising:
(A) a shielded case comprising:
(1) a plurality of walls, at least one of the walls being formed by at least first and second separate sections which abut one another along an interface; and
(2) one or more depression formed in at least one of the first and second sections so as to cause at least one of said sections to expand toward the other of said sections thereby pressure-welding said first and second sections along at least part of said interface; and
(B) an electronic component located in said shielded case.
In the electronic device according to the present invention, half walls of a shielded case are firmly coupled with each other, whereby a risk in that the sidewalls remove from each other and an electronic element received in the shielded case is exposed to the outside when an impact is applied is avoided.
An electronic circuit according to the present invention contains a plurality of components, at least one of said components being a shielded electronic device comprising:
(A) a shielded case comprising:
(1) a plurality of walls, at least one of the walls being formed by at least first and second separate sections which abut one another along an interface; and
(2) one or more depression formed in at least one of the first and second sections so as to cause at least one of said sections to expand toward the other of said sections thereby pressure-welding said first and second sections along at least part of said interface; and
(B) an electronic component located in said shielded case.
In the electronic apparatus according to the present invention, an electronic device is used, in which a risk that the half walls of a shielded case will separate from each other and expose an electronic element received in the shielded case to external electromagnetic radiation when an impact is applied to the case is avoided.
According to the method of the present invention, a method for manufacturing a shielded electronic device comprises:
forming a wall by bending first and second separate sections of a flat plate toward one another with opposed edges of said first and second sections abutting one another; and
forming one or more depressions in said wall so that at least one of the first and second sections is expanded toward the other along an interface between said sections to pressure weld said sections together.


REFERENCES:
patent: 5354951 (1994-10-01), Lange et al.
patent: 5883791 (1999-03-01), Deguchi
patent: 6194653 (2001-02-01), McMiller et al.
patent: 6313400 (2001-11-01), Mosquera et al.
patent: 02-52481 (1990-04-01), None
patent: 02-76880 (1990-06-01), None
patent: 08-130846 (1996-05-01), None

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