slide 1: A Detailed Guide on Designing of a Membrane Switch
For electronic devices especially consumer goods the “feel” and ease of use can either make or
break a new product just as much innovation or quality. Put it simply the user interface has to
look and perform great. What many people do not realize is that it‟s the membrane switch
technology that has made it possible for companies to develop more convenient gadgets. You
will find that microwaves computer keyboards and many other similar devices work on the
same technology. Likewise if you plan to transform your business products and operations
consider trying the same technology.
Still flummoxed and trying to wrap your head around the concept of membrane switches and
their method of operation These electronic switches play a key role in the application of
numerous modern-day gadgets. From microwave ovens and air conditioners to watches and TV
remotes membrane switches are used in a variety of devices.
But how exactly do they work This is the question that we are going to talk about in today‟s
post. Learning more about the technology and its capabilities will help you realize its potential.
What are Membrane Switches
A membrane switch also known as membrane keypads or membrane panels are electrical
switches with a user interface to control machines and equipment. Unlike mechanical switches
slide 2: which are generally constructed of plastics and copper membrane switches are printed circuits
on film.
How do Membrane Switches Work
The operation behind membrane switches is simple: when an operator wants to use the device a
switch is pressed so that the system‟s two poles make contact and close the circuit. When the
switch is released the poles are then disconnected and the switch returns to its open state.
For Which Industries Are Membrane Switches Used In
slide 3: Membrane switches can be created for a variety of environments and industries. They are used in
a number of applications including in defense aerospace medical automotive and industrial
industries. They are often used for keypads touch screen phones kidney dialysis machines and
control panels in aircraft – just to name a few.
Membrane switches are known for their high conductivity and reliability. They are revered for
their flexibility and durability especially in low and hig- temperature environments.
Membrane Switch Assembly
Although a membrane switch can be custom-made in various ways a typical switch is designed
with 4-6 layers to function properly. These layers include:
1. Presentation Layer:
This top layer of the membrane switch also known as graphic interface is used to create a visual
interaction between the machine and the user.
2. Adhesive Layer:
This is typically the 5
th
layer where adhesive glue is used to bond the unit together.
3. Separation Layer:
This layer is generally made of Polyester.
In a tactile switch this layer has a metal dome which sits in the space. If there would
have been no separation layer for the dome it would be pre-actuated and not have a nice
„snap‟ feel.
In a non-tactile switch this layer creates the space between the lower and upper circuit so
that when the user presses down the upper and lower circuits make contact and close.
4. Circuit Layer:
This circuit is required to move electricity from one place to another. Therefore this is the layer
which transfers command transformation to the machine. To accomplish this there is printed
conductive silver ink on the circuit which is typically made out of polyester.
In some cases this layer may include surface mount devices like resistors and LED.
Additional Custom Elements:
slide 4: Apart from the above described layers there are also plenty of other custom elements which can
get integrated as per customers‟ product specifications. Those additional custom elements
include:
Indicator LEDs:
This indicator is used to communicate a function or action which is currently in progress or over.
Backlighting:
There are various ways to incorporate backlighting with membrane switches:
LEDs: This type of backlighting is the best for small symbols or icons.
LGF Light Guided Film: This is one of the most successful and common methods of
interface backlighting. This is designed to evenly distribute uniformed and bright light
while reducing the number of LEDs required for proper lighting. Thus this is one of the
ways to help save power consumption.
Electroluminescence EL Technology: This technology is commonly used in GPS
systems and cell phones. This is an additional thin layer between the circuit and the
graphic overlay. The technology uses a phosphor deposit to illuminate the switch.
Electrostatic Discharge ESD Shielding: This is commonly used within medical
instruments. Membrane switch design sometimes requires ESD shielding for static
discharge to destroy the electronics the switch plugs into.
You can learn more about the design and working of a custom membrane switch with ElecFlex.
Visit us in case of any questions you may have.