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, 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?

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 5th 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:

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.

This article is written by C khuzwayo on behalf of Elecflex.com, this is having topics on Membrane Switch, Membrane Switch Manufacturer, Membrane Keypad, Membrane keyboard, Graphic Overlay and many more.