What are membrane switches?
Membrane switches are a type of user interface made up of a number of layers. These layers include:
- The graphical overlay
- Spacer layers
- Circuit layers
- Adhesive layers
- The backing layer
Icons, symbols, logos, and other graphics are printed onto the graphical overlay to provide information to users. When a button on the switch is pressed, the layers of the switch make contact with each other. Conductive inks are printed onto some of these layers—when the inks come in contact with the circuit layers, circuits are completed, and a function of the device is activated (or deactivated).
What are mechanical switches?
Mechanical switches are another type of user interface. They’re generally comprised of a number of parts, including:
- A plunger
- A spring
- Electrical contacts
When the plunger is pressed, it pushes down on the spring, which moves the electrical contacts together, completing a circuit. Once the plunger is released, the electrical contacts move apart, breaking the circuit.
Icons, symbols, logos, and other graphics can be printed or painted onto the housing to provide the user with more information about each switch’s function. In many instances, a printed graphic overlay with embossed keys is used as the client interface.
Both membrane switches and mechanical switches have advantages and disadvantages. Let’s delve deeper into each:
Pros and cons of membrane switches
The advantages of membrane switches
- They’re seamless. Mechanical switches have gaps—gaps that can accumulate contaminants. Membrane switches don’t. This means that membrane switches are easier to clean, and less prone to contamination. These traits make membrane switches the superior option for medical devices intended for healthcare facilities. It can also mean a longer lifespan, as contaminants can contribute to wear and tear in mechanical switches.
- They’re thin. Manufacturers have a number of reasons to value the sleek profile offered by membrane switches: Aesthetics, the need to fit within tight tolerances, a smaller, more portable product, and more. Despite being extremely thin, membrane switches can still be customized in a number of ways.
- They’re flexible. Need a user interface with a thin profile on a device that’s circular, or oddly angled? A membrane switch is the way to go. The flexible materials (and the conductive inks printed onto those substrates) can be shaped to fit almost any device you can imagine.
- They’re durable. Membrane switches don’t have the same number of moving parts as their mechanical counterparts. With mechanical switches, springs, contacts, and plungers can all fail. With membrane switches, everything is built in layers—the only movement is the displacement of the flexible layers through touch.
- They’re customizable. The manufacturing process used to create membrane switches allows for a high degree of customizability. Backlighting, dead fronting, and graphics of any shape and color are all available with membrane switches—and that’s just the tip of the iceberg.
The disadvantages of membrane switches
- They can be more expensive. The process for creating membrane switches is more complex than the process used for creating mechanical switches. Depending on the quantity of switches needed (and the complexity of the switches), membrane switches may be more expensive.
- They can take longer to manufacture. Complexity strikes again—it can take longer to create a working prototype for a membrane switch, given their complexity. Once the process of constructing the switches goes to scale, however, membrane switches can be manufactured rapidly.
- Some users may prefer mechanical switches. Mechanical switches have been around since the 1800s—more people are accustomed to using them than membrane switches. Some users also prefer the more tactile feel of mechanical switches.
Pros and cons of mechanical switches
The advantages of mechanical switches
- Highly customizable tactile feedback. While membrane switches can offer tactile switches through metal dome arrays, there’s greater customizability in the tactile feedback of mechanical switches. Everything from actuation force to the travel distance of the spring can be highly customized, and buttons can vary widely in size, texture, and other tactile features.
- Greater precision. The buttons of a mechanical switch are easier to differentiate—while all the buttons of a membrane switch can be printed on the same material, each button in an interface using mechanical switches is manufactured individually. This makes mechanical switches a good option for interfaces where highly distinct buttons are necessary.
- Consistency. With precision comes consistency. Users have no choice but to press on a mechanical switch in the right spot each time, as each button is its own separate switch—generally on a raised surface. The feel of a mechanical switch is also the same over time. This combination of clearly delineated buttons and tactile feedback can lead to a more consistent user experience.
The disadvantages of mechanical switches
- Noise. Mechanical switches generally make clicking or popping noises when they’re pressed in, especially if significant actuation force is needed to activate the switch.
- Cost-at-scale. Mechanical switches can be more costly to create in bulk than membrane switches, as they’re not created through a process of printing and layering.
Membrane switches are typically made using layers of plastics, including polyester and polycarbonate. LEDs and metal domes are commonly incorporated into membrane switches. Various adhesives are used to create the adhesive layer, and conductive inks made using copper, silver, and other metals are used to create a circuit when they touch the circuit layer.
Mechanical switches are made using a variety of metals and plastics for the housing, plunger, springs, and contacts. Contacts are often gold-plated—it all depends on the overall design of the mechanical switch.
When it comes to flexibility, membrane switches are the way to go. They’re created using flexible plastics and conductive inks, and can be designed to fit all kinds of different devices.
Mechanical switches are not flexible, though this rigidity has the advantage of offering very clearly delineated buttons over the surface of a user interface.
Both membrane switches and mechanical switches are highly durable, and with either type of switch, manufacturers can expect a life cycle of over a million actuations.
Typically, mechanical switches have a longer theoretical lifespan than membrane switches. Mechanical switches are not seamless, however, and that leaves them at a significant disadvantage when it comes to wear and tear as a result of contaminants.
Both membrane switches and mechanical switches have their advantages—whether you want to use a membrane switch or a mechanical switch array for your product depends heavily on the environment it will be used in, the end user, and many other factors.
Interested in designing a membrane switch for the user interface of your product, then manufacturing that switch to scale? Contact General Label today.