Electricity: circuit makers and breakers – Solid contact – Membrane type
Reexamination Certificate
2003-05-23
2004-07-27
Enad, Elvin (Department: 2832)
Electricity: circuit makers and breakers
Solid contact
Membrane type
C200S314000
Reexamination Certificate
active
06768075
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a membrane switch, which is produced by interposing a spacer between flexible films having conductor circuits formed by the printing or the like. The present invention also relates to a dial operation member, which is equipped with such a membrane switch.
2. Description of the Related Art
Such a membrane switch is used as a switch including electrical circuits, which are formed by printing a conductive paste onto flexible substrates, such as polyester films or the like. The membrane switch is used as a lightweight, thin and flexible switch, and therefore is particularly useful for mass production. These significant features of the membrane switch allow it to be used in a wide application field, for instance, in a keyboard for a computer, a home electrical appliance, a portable communication device, such as a cellar phone, a component for an automobile, a musical instrument, a medical appliance and others.
FIG. 7
is a plan view of a conventional membrane switch.
FIG. 8
is a plan view of a lower contact sheet in the conventional membrane switch.
FIG. 9
is a plan view of an upper contact sheet in the conventional membrane switch.
FIG. 10A
is a sectional view of the conventional membrane switch in the non-conductive state, and
FIG. 10B
is a sectional view of the conventional membrane switch in the conductive state.
Such a conventional membrane switch
110
comprises a lower contact sheet
111
, an upper contact sheet
112
, a spacer
113
, a connector
114
and others, as shown in
FIGS. 7-10
. The lower contact sheet
111
includes a conductor
111
a
and a projection portion
111
b
, as shown in FIG.
8
. The conductor
111
a
includes several sets of paired contact areas
111
c
and
111
d
, each end of which is ramified in the form of an approximately U shape. The upper contact sheet
112
includes circular contact areas
112
a
, which are used to come into contact with the corresponding contact areas
111
c
and
111
d
in the conductive state, as shown in FIG.
9
. In the spacer
113
, there are through holes
113
a
, through which paired contact areas
111
c
and
111
d
on the side of the lower contact sheet
111
and corresponding contact areas
112
a
on the side of the upper contact sheet
112
come into contact with each other in the conductive state, as shown in FIG.
7
. The projection portion
111
b
which is part of the lower contact sheet
111
including part of the conductor
111
a
is inserted into the connector
114
.
In the following, the function of the conventional membrane switch will be described.
When trying to push a projection portion
109
d
to bend the upper contact sheet
112
in the lower direction by pushing a projection portion
109
d
, as shown in
FIG. 10A
, the contact area
112
a
is in contact with the paired contact areas
111
c
and
111
d
, as shown in FIG.
10
B. Accordingly, the contact area
112
a
is directly connected to the paired contact areas
111
c
and
111
d
, so that the membrane switch
110
turns on in the conductive state (the ON state).
In the conventional membrane switch
110
, there is a problem in which a decrease in the press force acting to the upper contact sheet
112
occasionally causes the contact area
112
a
to come in contact with only one of the paired contact areas
111
c
and
111
d
, so that the membrane switch
110
does not turn on in the conductive state. Furthermore, in order to securely connect the contact area
112
a
with both the contact areas
111
c
and
111
d
in the conventional membrane switch
110
, it is necessary that the projection portion
109
d
made of a resilient material, such as gum or the like, presses against the upper contact sheet
112
with a press force greater than a predetermined force. This also provides an increase in the production cost, since the number of the parts constituting the membrane switch
110
is inevitably increased.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a membrane switch capable of turning on even with a very small weight.
It is another object of the present invention to provide a dial operation member, which is equipped with such a membrane switch.
In accordance with a first aspect of the invention, a membrane switch comprises,
(a) a first base element made of an electrical insulation elastic material, the first base element having a first conductor including at least one press contact area and at least one permanent contact area on a surface of the first base element;
(b) a second base element made of an electrical insulation material, the second base element having a second conductor and a third conductor on a surface facing the surface of the first base element,
the second conductor including at least one press contact area in accordance with the arrangement of the at least one press contact area in the first conductor, and
the third conductor including at least one permanent contact area in accordance with the arrangement of the at least one permanent contact area in the first conductor,
the second base element further having a connector section for connecting the second and third conductors to an external circuit; and
(c) a spacer made of an electrical insulation material, the spacer being interposed between the first base element and the second element, the spacer having through holes at positions corresponding to those both in the at least one press contact area and the at least one permanent contact area of the first and second base elements.
In accordance with a second aspect of the invention, a membrane switch comprises,
(a) a first base element made of an electrical insulation elastic material, the first base element having a first conductor including at least one press contact area, a second conductor including at least one permanent contact area and a connector section for connecting the first and second conductors to an external circuit on a surface of the first base element;
(b) a second base element made of an electrical insulation material, the second base element having a third conductor on the surface facing the surface of the first base element, the third conductor including at least one press contact area in accordance with the arrangement of the at least one press contact area disposed in the first conductor and the at least one permanent contact area in accordance with the arrangement of the at least one permanent contact area disposed in the first conductor; and
(c) a spacer made of an electrical insulation material interposed between the first base element and the second base element, the spacer having through holes in accordance with the arrangement of the at least one press contact area and the at least one permanent contact area.
In accordance with a third aspect of the invention, a dial operation member comprises,
(a) a shaft;
(b) a bearing through which the shaft passes;
(c) a dial body fixed to the shaft and rotatably supported around the center axis of the shaft;
(d) a press member for switch disposed so at to face the dial body for switching, the press member having at least one press projection portion for switching; and
(e) one of the above mentioned membrane switches, wherein at least one press portion for switching is disposed so as to face the at least press projection for switching in the press member for switch.
Further objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiment with reference to the accompanying drawings.
REFERENCES:
patent: 4987275 (1991-01-01), Miller et al.
patent: 5152392 (1992-10-01), Iwasa
patent: 6392178 (2002-05-01), Kuratani
patent: 6486427 (2002-11-01), Pruvot
patent: 6670750 (2003-12-01), Hanahara et al.
patent: 06-034140 (1994-02-01), None
Enad Elvin
Katten Muchin Zavis & Rosenman
Klaus Lisa
Teac Corporation
LandOfFree
Membrane switch and dial operation member equipped therewith does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Membrane switch and dial operation member equipped therewith, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Membrane switch and dial operation member equipped therewith will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3221077