Electricity: circuit makers and breakers – Solid contact – Membrane type
Reexamination Certificate
2001-07-18
2003-04-15
Enad, Elvin (Department: 2832)
Electricity: circuit makers and breakers
Solid contact
Membrane type
Reexamination Certificate
active
06548779
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sheet having moving contacts used in an operation panel or the like of various types of electronic devices, and a sheet switch employing the same.
2. Description of the Prior Art
The structure of a conventional sheet having moving contacts and a sheet switch is shown in
FIGS. 6
to
8
.
FIG. 6
is an exploded perspective view showing a sheet having moving contacts that is provided with a spacer, and
FIGS. 7 and 8
are respectively a plan view and a sectional view showing a sheet having moving contacts and a sheet switch that has one sheet.
In
FIG. 6
, a sheet having moving contacts that is provided with a spacer comprises: moving contacts
13
each of which is a conductive plate domed at the center thereof; a sheet
11
made of an insulating film, which is coated with an adhesive on a lower face thereof and covers the upper faces of the moving contacts
13
; and a spacer sheet
12
made of an insulating film, which is stuck to the lower face of the sheet
11
and has housing holes
12
a
formed to house the moving contacts
13
.
The moving contacts
13
are housed in the housing holes
12
a
of the spacer sheet
12
, and the domed upper faces thereof are covered and fixed by the adhesive
14
applied to the lower face of the sheet
11
. The spacer sheet
12
are provided with coupling grooves
12
b
for coupling two adjacent housing holes
12
a
, whereby, when the moving contacts
13
are pressed, air within the dome of the domed moving contact
13
escapes to a different housing hole
12
a
through the coupling groove
12
b
, preventing reduction in operation feeling.
The sheet
11
and the spacer sheet
12
are provided with plural openings
11
a
and
12
c
used as holes for lighting from LED to be mounted on a circuit board and component escape holes.
A sheet having moving contacts in
FIG. 7
, not provided with a spacer sheet, comprises moving contacts
13
each of which is a conductive plate domed at the center thereof, and a sheet
16
made of an insulating film, which is coated with an adhesive on a lower face thereof and covers the upper faces of the moving contacts
13
.
In this case, an opening
16
a
(circular hole in the drawing) comprising a wide through hole is provided in a portion of the sheet
16
intersecting with the outer circumferential part
13
b
of the moving contact
13
, whereby, when the moving contact
13
is pressed, air within the domed moving contact
13
escapes to the outside through the opening
16
a
, preventing reduction in operation feeling.
A sheet switch shown in
FIG. 8
comprises the sheet having moving contacts, and a circuit board
17
which is provided with a central fixed contact
17
b
and outer fixed contacts
17
a
on an upper face thereof, wherein the sheet
16
having moving contacts is stuck onto the circuit board
17
by the adhesive
14
on the lower face of the sheet
16
so that lower ends of the outer circumferential edges
13
b
of the moving contact
13
of the sheet
16
having moving contacts are abutted on the external fixed contacts
17
a
, and the top
13
a
of the moving contact
13
faces the central fixed contact
17
b.
In the above configuration, when an operation part of a pushbutton (not shown) made of rubber or resin, disposed over the sheet switch, is pressed, the moving contact
13
pressed by a pressing part of a lower face of the operation part through the sheet
16
is inverted so that a lower face of the top
13
a
abuts on the central fixed contact
17
b
, whereby the central fixed contact
17
b
of the circuit board
17
and the outer fixed contacts
17
a
are electrically connected. If pressure to the pushbutton is removed, the resiliency of the moving contact
13
moves the top
13
a
of the moving contact
13
away from the central fixed contact
17
b
, turning the connection off.
However, in the structures of the conventional sheet having moving contacts and the sheet switch as described above, the structure of the sheet having moving contacts that is provided with a spacer has a problem in that, since the spacer sheet
12
is required, the number of parts increases, hampering cost reduction.
Also, the structure of a sheet having moving contacts employing one sheet has a problem in that, since the opening
16
a
opens largely in the direction of outer circumference of the moving contact
13
, dust may invade the moving contact
13
from the opening
16
a
when the moving contact
13
returns from the inversion.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a sheet having moving contacts and a sheet switch that are constructed so as to solve the above-described problems, contribute to lowering of costs by reducing the number of parts, provide satisfactory operation feeling by driving air out of the dome of the moving contacts when the moving contacts of the sheet having moving contacts and the sheet switch are pressed, and provide high contact reliability by preventing invasion of dust.
To solve the above problems, the present invention, as first means, comprises: a sheet having an adhesion face, made of an insulating film, which is coated with an adhesive on a lower face thereof; and a moving contact which has a domed expansion part and the upper face of which is covered with and stuck to the adhesion face of the sheet, wherein the sheet is formed with a linear slit extending toward the top of the expansion part across an outer circumferential edge of the moving contact.
As second means, the slit is formed in plural locations of the outer circumferential edge of the moving contact except the top of the domed expansion part thereof.
As third means, a plurality of the moving contact are stuck to the sheet, and the slits are formed inside a virtual outer circumferential line connecting the outer circumferential edges of the moving contacts placed in the outermost portions of the sheet.
As fourth means, the sheet has openings piercing vertically inside the virtual outer circumferential line, and the slits provided in the outer circumferential edges of the moving contacts disposed in the vicinity of the openings are formed in directions different from the position of the openings.
As fifth means, the sheet switch comprises: a sheet having moving contacts comprising a sheet made of an insulating film which has an adhesion face coated with an adhesive on a lower face thereof, and linear slits, and moving contacts which have a domed expansion part and are stuck to the adhesion face of the sheet so that the linear slits extend toward the top of the expansion part across an outer circumferential edge thereof; and a circuit board on which fixed contacts are mounted, wherein the sheet having moving contacts is stuck onto the circuit board by an adhesive of a lower face of the sheet in a state in which the moving contacts are disposed so as to face the fixed contacts.
REFERENCES:
patent: 4033030 (1977-07-01), Robinson et al.
patent: 4400595 (1983-08-01), Ahumada
patent: 5924555 (1999-07-01), Sadamori et al.
Iwama Naoya
Takahashi Katsutoshi
Yamagata Takeo
Alps Electric Co. ,Ltd.
Beyer Weaver & Thomas
Enad Elvin
Fishman M.
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