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Instrumentation
and Electronics Table of Content
Membrane Switch Manufacturing and Supply
| MetroMark Membrane Switches - www.metromark.com
Metromark has over twenty years experience in manufacturing the most reliable membrane switches used in industry. Using the latest in material technologies and design know-how, Metromark will create a precisely engineered product that fits your needs and your budget. |
Typical membrane switches incorporates the following
layered components:
- Graphic presentation layer
- Graphic adhesive layer
- Circuit or PCB layer
- Adhesive separator layer
- Optional second circuit or PCB layer
- Adhesive layer
Description of each Membrane Switch Layer:
The Graphic presentation layer of the membrane
switch is a graphic overlay. The configuration is dependant
on the function of the device. The graphic presentation
layer is typically a printed material, such as
polyester or silicone rubber.
Graphic adhesive layer facilitates the assembly of
the graphic presentation layer to the circuit layer which
receives the mechanical pressure applied to the membrane
switch domes. This
layer is typically made from polyester type material with
adhesive on both sides, and is normally designed a few
thousands of a inch smaller than the dome height. This is
done to allow a small preload on the dome to facilitate a
tactile feel on the selection pads. Sometimes, as dictated
by the membrane switch application, this layer
will include venting of the domes to allow the trapped air
within the dome to escape during actuation / pressing of the
pad-dome.
The Circuit or PCB layer includes the membrane
switch electronics, as well as the dome feature. The circuit
layer includes the "Interdigitated” switch pole pairs
for each button-dome combination of the membrane switch. .
Adhesive separator layer is an optional layer to
facilitate an additional circuitry required for some
Membrane switches applications. This layer will
accommodate interconnection to the dome circuit layer.
This layer will have adhesive on both sides for assembly.
Optional second circuit or PCB layer incorporates additional circuitry required
by the membrane switch application. This layer typically includes the necessary
flex cable or interface pins to integrate the membrane
switch.
Adhesive layer on the mounting surface of the
membrane switch is provided as a design option to mount the
membrane switch to the target installation. Membrane
switches may be designed into a plastic injection molded
enclosure or case with application mounting feet as well.
Note:
Metal domes used on membrane switches can be
designed with a wide range of stainless steel shapes and
degree of tactile responsiveness. Typical applications
may have 4 legs and be 12 mm square with trip or snap forces
between 200, to 500 grams.
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