Electricity: circuit makers and breakers – Solid contact – Membrane type
Reexamination Certificate
2001-03-13
2003-04-15
Luebke, Renee (Department: 2833)
Electricity: circuit makers and breakers
Solid contact
Membrane type
C200S515000
Reexamination Certificate
active
06548778
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sheet with plate springs to be used, for example, as a thin operating panel in such an electronic device as a portable telephone set or a video camera, as well as a switch device using the same.
2. Description of the Prior Art
With a panel switch as an example, a conventional sheet with plate springs and a conventional switch device using the conventional sheet with plate springs will be described with reference to
FIGS. 10
to
12
, of which
FIG. 10
is an exploded perspective view of a conventional sheet with plate springs,
FIG. 11
is a sectional view taken on line XI—XI in
FIG. 10
, and
FIG. 12
is an explanatory diagram explaining how to assemble a conventional switch device using the conventional sheet with plate springs.
The construction of a conventional sheet with plate springs will now be described with reference to
FIGS. 10 and 11
. Plural movable contacts
31
are each constituted by a thin, dome-like, metallic plate spring and can be displaced with click feeling when a depressing force is exerted thereon from its top portion.
Film
32
is a generally rectangular, large-sized, somewhat thick film with an adhesive layer affixed to a lower surface thereof. The film
32
has plural holes
32
a
which are formed through upper and lower surfaces of the film and which are each a little larger than each movable contact
31
.
The movable contacts
31
are respectively inserted into the holes
32
a.
A plurality of generally square adhesive sheets
33
, which are each a little larger than each hole
32
a
, are each constituted of a film with an adhesive layer affixed to the whole of its lower surface and are each formed with a through hole
33
a
generally centrally of one side of the sheet and in the vicinity of the side edge.
Each adhesive sheet
33
is affixed to an upper surface of each movable contact
31
and also affixed to the surface portion of the film
32
contiguous thereto, thereby fixing the movable contact
31
to the film
32
and holding it on the film.
The through holes
33
a
are respectively opposed to the holes
32
a
of the film with the movable contacts
31
received therein to provide communication of the holes
32
a
with the exterior.
A separator
34
is formed by a large-sized film or paper having substantially the same shape as the film
32
. The separator
34
is affixed to the lower surface of the film
32
through the adhesive layer formed on the film lower surface to protect lower surfaces of the movable contacts
31
so that dust and other foreign matters may not get into the interior of each movable contact dome. In this way there is constituted a sheet
35
with movable contacts (a sheet with plate springs).
A conventional switch device and how to assemble it will now be described with reference to FIG.
12
. The conventional switch device uses the conventional sheet
35
with movable contacts (sheet with plate springs) and includes a large-sized insulating substrate
36
. The insulating substrate
36
is a flexible substrate constituted of a polyimide film for example, and first and second fixed contacts
36
a
,
36
b
are formed on the surface of the insulating substrate
36
, for example, by etching copper foil or the like.
The adhesive layer applied to the lower surface of the film
32
in the sheet
35
with movable contacts is exposed by releasing the separator
34
affixed to the film lower surface, allowing the holes
32
a
to be opposed to the first and second fixed contacts
36
a
,
36
b
, and in this state the film
32
is affixed to an upper surface of the insulating substrate
36
to assemble a switch device.
In this state, the movable contacts
31
are placed on the surface of the insulating substrate
36
in such a manner that the peripheral edge of a lower end portion of each movable contact
31
is constantly in contact with the associated second fixed contacts
36
b
and that the dome-like top of each movable contact
31
is spaced from and opposed to the associated first fixed contact
36
a.
Next, the operation of the conventional switch device constructed as above will be described. If an operator depresses the adhesive sheet
33
located above a movable contact
31
through an operating member (not shown), an upper portion of the movable contact
31
is inverted concavely and comes into contact with the associated first fixed contact
36
a
to turn ON between the first and second fixed contacts
36
a
,
36
b.
At this time, the air present within the dome of the movable contact
31
flows out from an end portion of the movable contact
31
, then passes through the associated hole
32
a
formed in the film
32
and further through the through hole
33
a
formed in the associated adhesive sheet
33
, and escapes to the exterior.
Upon release of the depressing force, the upper portion of the movable contact
31
leaves the first fixed contact
36
a
, thus turning OFF between the first and second fixed contacts
36
a
,
36
b.
At this time, air flows into the dome through the through hole
33
a
formed in the adhesive sheet
33
.
However, since the conventional sheet with plate springs requires the film
32
for insertion therein of the movable contacts
31
formed of plate springs and also requires the adhesive sheets
33
for fixing the movable contacts adhesively, the number of components used is large to result in an increase of cost.
In addition, since the adhesive sheets
33
are affixed to the movable contacts
31
(plate springs) one by one, considerable time and labor are required for the affixing work, thus giving rise to the problem that the productivity is low.
Moreover, since the holes
32
a
formed in the film
32
are directly connected to the exterior through the through holes
33
a
formed in the adhesive sheets
33
, dust and other foreign matters are apt to get into the holes
32
a
from the exterior.
Further, in the conventional switch device using the conventional sheet with plate springs, not only dust and other foreign matters are apt to get into the holes
32
a
of the film
32
from the exterior because the holes
32
a
are in direct communication with the exterior, but also in the case where electronic parts are mounted on the insulating substrate
36
, the electronic parts become more likely to be destroyed by static electricity charged on the hands and fingers of the operator.
Further, since the film
32
having holes
32
a
for fitting therein of the movable contacts
31
(plate springs), as well as plural adhesive sheets
33
, are required, the productivity is low, the number of components used increases, the cost becomes high, and the thickness of the switch device increases.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a sheet with plate springs capable of preventing the entry of dust and other foreign matters from the exterior and which is inexpensive, as well as a switch device capable of preventing the entry of dust and other foreign matters from the exterior and which is thin and strong against static electricity.
According to a first apparatus adopted by the invention for solving the above-mentioned problems there is provided a sheet with plate springs, comprising an adhesive sheet having adhesive portions on one side thereof, a plurality of plate springs each constituted of a deformable metallic plate having resilience and with the adhesive portions affixed to upper surfaces thereof, and a sheet-like separator affixed to the adhesive sheet to protect lower surfaces of the plate springs, wherein the one side of the adhesive sheet is studded with the adhesive portions each in a projected form, and vent portions are formed between the studded and projected adhesive portions and between the plate springs and the exterior of the adhesive sheet so that air can get into and out of the vent portions.
According to a second apparatus adopted by the invention there is provided, in combination with the above first apparatus, a sheet with plate springs wherein the total a
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Luebke Renee
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