Membrane Switches – The Ultimate Guide

A membrane switch is simply a power on or off button that exploits pressure rather than moving components to switch on or off a circuit. This switch does not necessitate any moving parts and this has heightened its prominence in numerous electronic appliances.

Primary Functions of a Membrane Switch

Membrane Switches
Membrane Switches

Membrane switches, just like your typical mechanical switch are multifunctional interfaces. They accomplish numerous functions, key amongst them being;

  • User Input: Primarily, membrane switches register your presses before translating them into signals and transmitting them to your electronic components. Simply put, they act as your keypad or button, which initiates an interaction with your parent device.
  • Data Entry: In addition to registering your presses, they also allow you to press numbers or navigate your device’s menu. This means that you can utilize them as alternative keyboards.
  • Status Indication: This application is only fulfilled by limited membrane switches, particularly those endowed with LED backlighting. Using visual indicators, they unveil your device’s status.
  • Level Control: You can also utilize your membrane switch to regulate various settings or adjust certain levels. If your membrane switch is endowed with a touch-sensitive slider you can use it to your device’s audio volume.

Membrane Switch Main Features

Thanks to their unique set of features, membrane switches have proven their indispensability in most applications. Some of these unique properties include;

  • Tactile Feedback: This feature is responsible for the reaction you realize after pressing your membrane switch. For instance, once you press your switch, you will hear a click sound, which acts as confirmation that you have activated the button.
  • Lean Appearance: The numerous layers of membrane switches are tightly packed and they are made from compact materials. This makes them perfect for use in devices or applications with limited space.
  • Backlighting Feature: To facilitate the use of membrane switches in dark settings, some switches are endowed with illuminating components such as LEDs.
  • Noiseless: The operation principle of membrane switches is virtually noiseless due to the elimination of moving components. They instead rely on pressure meaning that their operation is practically silent compared to their mechanical counterparts.
  • Customizability: You can have your switch’s size, shape, or construction material tailored to meet your demands.
  • Power Efficiency: Membrane switches only necessitate a small amount of energy to run. This makes them an energy-efficient alternative that you can power using low-range batteries.
  • Multifunctionality: Equipped with distinct components and with each component tasked with a distinct role, these switches serve more than two masters. You can exploit them to adjust settings, input user data and indicate device status.
Membrane Switches Components
Membrane Switches Components

Types of Membrane Switches

Today, you interact with at least 10s of electrical devices and most of these devices depend on membrane switches. As such, these components are manufactured with distinct features as evidenced by the different types of membrane switches outlined below.

Tactile Membrane Switches

Tactile membrane switches are known for the physical sensation they generate once you press or activate them. Once you press a tactile switch, you will hear a clicking sound, which will keep you from accidentally pressing the same button twice or thrice. This makes these types of membrane switches perfect for control panels and keyboards.

Tactile Membrane Switches
Tactile Membrane Switches

Non-Tactile Membrane Switches

These membrane switches are deprived of the physical sensation that comes with their tactile counterparts thereby qualifying their deployment in sensitive applications. They are the exact opposite of tactile switches, meaning that they hardly emit a click sound upon activation. To confirm activation, they may provide you with a visual confirmation. They are primarily used in medical devices.

Non Tactile Membrane Switches
Non Tactile Membrane Switches

Single-Sided Membrane Switches

Single-sided membrane switches are known for their simplicity and affordability. They are characterized by a single-layered material meaning they are lighter in weight and relatively affordable to produce. However, their application is limited to low-complexity interfaces.

Single Sided Membrane Switches
Single Sided Membrane Switches

Double-Sided Membrane Switches

Unlike their one-sided switches, double-sided membrane switches come with two sides and each side features printed graphics and circuitry. This means that these switches can fulfill relatively more complex roles hence they are widely exploited in industrial control systems.

Double Sided Membrane Switches
Double Sided Membrane Switches

Backlit Membrane Switches

Backlit membrane switches are special switches endowed with the additional feature of an illuminating background. This feature allows you to comfortably use these switches in low-light conditions, for instance, at night. There are numerous types of backlit membrane switches for you to choose from.

  • LED Backlit Membrane Switches: These are backlit membrane switches that depend on light-emitting diodes to provide the background illumination. They are available in a range of colors and they focus the light on specified switch areas, making it easier for you to use your switch.
  • EL Backlit Membrane Switches: Unlike LED backlit membrane switches, which focus the light on certain switch areas, these switches focus the light across greater areas. Electroluminescence backlit membrane switches are also dimmable meaning you can alter the light’s brightness.
  • Fiber Optic Backlit Membrane Switches: These unique backlit membrane switches are renowned for their uniform glow, which is facilitated by the use of fiber optic backlighting. The backlighting effect achieved by these switches seems more high-end due to the even illumination.
an Example of a Backlit Membrane Switch
an Example of a Backlit Membrane Switch

Pros of Backlit Membrane Switches

  • Better vision in low-light settings.
  • Focused illumination on targeted areas such as the indicator lights.
  • Makes it easier for disabled people to operate the switch.
  • Makes it easier for everyone to operate the membrane switch.
  • Gives your switch a contemporary feel and aesthetic.

Non-Backlit Membrane Switches

Non-backlit membrane switches are essential simple switches designed to favor applications that hardly demand backlighting. As such, they are not fitted with illumination components, meaning they exhibit a simpler design and are quite affordable. Their use is primarily limited to well-lit environments.

An Example of non backlit Membrane Switch
An Example of Non-backlit Membrane Switch

Capacitive Membrane Switches

Capacitive membrane switches are renowned for their reliance on subtle touch. Their sensitivity is quite high, almost matching that of a touchscreen. They rely on capacitance changes to sense your proximity or touch. This unique mode of operation makes them resistant to wear and tear hence they are highly deployed in touchscreen controls.

Capacitive Membrane Switch
Capacitive Membrane Switch

Metal Dome Membrane Switches

These membrane switches are named after the type of component they utilize to emit their tactile physical sensation. Whenever you press a button on this type of switch, the metal dome caves in resulting in sound generation. These domes hardly wear out, making these types of membrane switches extremely long-lasting and dependable.

Metal Dome Membrane Switch
Metal Dome Membrane Switch

Polydome Membrane Switches

These membrane switches are a worthy competitor of metal dome membrane switches and they are fitted with polymeric domes. These domes are the exact opposite of metal domes, which are known for producing relatively louder tactile feedback. Polymeric domes on the contrary are more subtle and soft hence they are often employed in consumer electronics.

Polydome Membrane Switch
Polydome Membrane Switch

Piezo Membrane Switches

Piezo membrane switches are renowned for their reliability and soft tactile feedback. This is enabled by their reliance on the piezoelectric effect, which gives rise to a voltage whenever you hit the switch’s button.

Piezo Membrane Switch
Piezo Membrane Switch

Waterproof Membrane Switches

These specialized membrane switches can function optimally even when exposed to moisture or other liquids. This is facilitated by the waterproof materials used to construct them as well as the watertight sealing mechanisms employed. Waterproof membrane switches are primarily utilized in outdoor applications.

Waterproof Membrane Switch
Waterproof Membrane Switch

Resistive Membrane Switches

Resistive membrane switches are the exact opposite of capacitive membrane switches. To sense your touch, they exploit your hand’s resistance. This means that you must apply a considerable amount of pressure to activate a resistive membrane switch.

Resistive Membrane Switch
Resistive Membrane Switch

Elastomeric Membrane Switches

These membrane switches are identifiable by their rubber-like graphic overlay and switch buttons. This elastomeric material makes them quite flexible and resistant to wear or tear. When using an elastomeric membrane switch, you will realize that it has a very robust tactile twist.

Elastomeric Membrane Switch
Elastomeric Membrane Switch

Construction of A Membrane Switch

Do not be deceived by the simplicity and thin profile of membrane switches. These switches pack numerous layers of distinct materials and components, each customized to fulfill distinct roles. Here, we peel back their intricate construction to give you a better understanding of their make-up.

  • Graphic Overlay: This is the component that allows you to interact with your membrane switch. It is the exterior layer of your membrane switch and it can be manufactured from long-lasting materials like polycarbonate and polyester. This layer displays the branding and labels of your switch and is also tasked with elevating aesthetic appeal.
  • Graphic Adhesive: The graphic adhesive layer is sandwiched between your switch’s graphic overlay and top circuitry. It is simply a layer consisting of an adhesive responsible for securing your top circuitry and graphic overlay together.
  • Dome Retainer: This is commonly known as the top circuitry and is typically made of conductive traces. These traces generate the electrical pathways that facilitate the functioning of your switch’s matrix. The dome retainer also detects your touch whenever you press your membrane switch and is often manufactured from an elastic polyester.
  • Dome Separator: The dome space is a wafer-thin insulating layer designed to avert unintentional circuit activation in your membrane switch. This layer sits between your lower circuitry and your exterior circuitry. It is typically manufactured from polyesters or polyethylene injected with distinct adhesives.
  • Bottom Circuit: This layer sits beneath the dome spacer and is quite similar to the dome retainer. These layers are in fact made from similar materials and feature a similar construction. However, this lower circuit layer helps complete the circuit whenever you press your membrane switch. It is the coordination of this bottom circuit and the top circuit that activates your switch.
  • Rear Adhesive: The rear adhesive is a layer comprising of a robust adhesive that binds your bottom circuit layer to your switch’s mounting surface or casing. This layer does not only hold your bottom layer in place, but it also ensures that your entire membrane switch is firmly housed.
  • LED Backlighting: This component or layer of LEDs is only synonymous with LED backlit membrane switches. It is responsible for illuminating light at targeted switch areas thereby allowing you to use your membrane switch in low-light conditions.
  • Tactile Domes: This is a layer present in tactile membrane switches. It is tasked with generating that clicking sound that lets you know you have pressed a button on your switch. Your membrane switch may be fitted with different types of tactile domes but the most prominent are metal and polymeric domes.
  • EMI Shielding: This is an additional layer incorporated into membrane switches meant to be deployed in settings prone to electromagnetic interference. As such, this feature keeps your membrane switch operating optimally irrespective of the conditions it is subjected to.

How Does a Membrane Switch Function

Membrane switches are known for their additional functions and simplicity. They are different from mechanical switches and their operational processes prove this. Here is a breakdown of their working principles.

  • Pressing: The operation of your membrane switch commences once you press a specified button or area of your switch’s graphic overlay. By pressing the switch, you are simply applying pressure on the graphic layer or top-most layer and this pressure trickles down to the bottom layer.
  • Circuit Connection: The pressure you have exerted on the graphic overlay trickles down to the top circuit and subsequently to the dome separator. This consequently shrinks the dome space resulting in contact between the top and bottom circuits.
  • Circuit Activation: With the dome space deformed and contact between the bottom and top circuits initiated, the circuit is completed. You must note that only the circuit of the pressed area is completed. This activation may differ depending on the type of switch you are using.
    • Latching Switch: If you have a latching membrane switch and the top and bottom circuits initiate contact, the resulting circuit will remain active. Releasing the applied pressure does not necessarily circuit. To open the circuit, you will be necessitated to press another area of your membrane switch.
    • Momentary Switch: If you have a momentary membrane switch, the completed circuit breaks open immediately when you relieve the applied pressure. This is because releasing the pressure frees the dome space, which subsequently breaks contact between the top and bottom circuits.
  • Signal Transmission: The completion of the circuit brought about by the merging of the top and bottom circuits then prompts the transmission of a signal. This signal is relayed to a control system whose task is to process and interpret the signal. After interpretation, the control system initiates a corresponding action.
  • Release: Once the corresponding action has been initiated and you have removed your finger from the switch, a reset action is initiated. This means that your membrane switch returns to its natural state where the top and bottom circuits are separated by a dome separator.

Designing a Membrane Switch

When designing a membrane switch you must pay special attention to numerous factors to ensure that your switch gratifies your functional and aesthetic demands. Here are some of the most essential considerations you cannot afford to ignore.

Define Your Purpose: Prior to starting your membrane switch construction project, you must first define the expected role of your switch. Come up with a list that specifies the following features;

  • Mechanical specifications such as tactile feedback and size.
  • Electrical specifications such as voltage level and type of circuitry.
  • Aesthetic preference such as the color and branding.
  • Required regulatory certifications such as UL and CE regulations.

Material Selection: After you have clearly defined your membrane switch requirements, it is time to settle on the best material for each layer of your switch. Here are some materials you may consider;

  • Graphic Overlay: Polycarbonate or polyester.
  • Conductive traces: Copper or silver.
  • Dome separator: Polyimide or polyester.
  • Adhesives: Pressure-sensitive adhesives.

Circuit Layout: Designing the layout of your circuit is an essential step in membrane switch designing given that it directly impacts functionality. Thankfully, you can utilize numerous software including computer-aided designing (CAD). In your design, factor in the following;

  • Routing paths.
  • Conductive traces placement.
  • Integration of additional components such as LEDs and connectors.

Some of the circuit layouts you may exploit include;

  • Matrix Layout: This design will leave your membrane switch with a circuit structure defined by rows and columns. This layout is primarily ideal for membrane switches comprising numerous buttons but may be vulnerable to crosstalk.
  • Common BUS Layout: This layout has distinct traces routed to specified buttons on your membrane switch. This is because this design relies on a single bus line, which makes it a simple and low-cost layout.
Membrane Switch Design
Membrane Switch Design

Graphic Overlay Designing: The graphic overlay is the interface that is visible to you or the users of your membrane switch. When designing it, you must factor in numerous elements to ensure that you strike a balance between functionality and aesthetic appeal. These factors include;

  • Color selection
  • Texture selection
  • Type of finish
  • Icon and text placement
  • Embossing
  • Debossing

Prototyping and Testing: Prototyping is an essential process especially when you are designing membrane switches for large-scale production. It involves creating a few samples before producing the final product. Once you have your prototype, proceed to test it. Test the following features;

  • Action force
  • Tactile feedback
  • Electrical continuity
  • Signal integrity
  • Compatibility

Benefits of Membrane Switches

With the demand for input interfaces constantly heightening, the prominence of membrane switches today is not a surprise. These unique switches promise a myriad of unique benefits, which include;

  • Thin and Lightweight: Despite being multi-layered, membrane switches are wafer-thin and this gives them a considerably low weight. As such, you can utilize them in devices with space limitations.
  • Water Resistant: Membrane switches come with a sealed construction, which keeps moisture and water from reaching the internal components.
  • Dust Proof: The sealed construction of membrane switches also keeps them safe from dust and debris, which can compromise the functionality of distinct components.
  • Easy to Clean: Typical membrane switches come with a smooth or slightly textured surface, which makes the cleaning process easier for you.
  • Durable: Unlike their mechanical counterparts, membrane switches hardly utilize moving components and this shrinks the chances of wear or tear. Furthermore, they are manufactured from robust materials, thereby elevating their lifespan.
  • Quiet Operation: Membrane switches, particularly non-tactile membranes have no tactile feedback meaning they operate in total silence. This permits their use in noise-sensitive applications like controlling medical devices.
  • Seamless Integration: You can easily use your membrane switch with numerous electrical devices including PCBs and microcontrollers. This is due to the incorporation of embedded electronics and conductive inks.

Choosing The Best Membrane Switch

The type or brand of membrane switch you settle on hugely impacts its effectiveness and performance. The underlying tips should guide you in choosing the ideal membrane switch for your respective application.

  • Intended Use: Think about the specific role you want to accord your membrane switch. Does it have the required properties or specifications to adequately serve that role?
  • Use Environment: Understanding the environment in which your membrane switch will be deployed and the prevailing conditions will help you choose the best construction material. For instance, if you intend to use it in outdoor applications, a switch with a more robust sealing would be better.
  • Basic Features: What features and technologies does the membrane switch offer? For instance, if your membrane switch will be used in low-light settings, make certain that it supports LED backlighting.
  • Layout and Design: Factor in the number of buttons you want in your switch and how they will be arranged. For instance, a matrix layout may suit you better if you want your membrane switch to feature a complex button layout.
  • Electrical Specifications: You will need to think about numerous electrical specifications including voltage and current. Also, take into consideration the electrical requirements of your parent device to guarantee compatibility.
  • Regulatory Compliance: The manufacturing and use of electrical components are strictly governed by numerous regulations including UL and RoHS. Make certain that your chosen membrane switch conforms to these standards.

Care Tips for Membrane Switches

Looking after your membrane switch properly comes with a myriad of rewards including improved performances and longer lifespans. Here are a few care tips to help you look after your membrane switch:

  • Cleaning: Clean your membrane switch frequently using a soft cloth to avoid scratching its surface.
  • Keep Liquids Away: Avoid placing your membrane switch in places where drinks or other liquids may spill onto it. This is because liquids can interfere with its circuit layout.
  • Conduct Regular Inspections: Once in a while, test the functioning of different components such as buttons. If there are worn-out components, replace them early.
  • Be Gentle: When using the membrane switch avoid using excessive force or slamming the switch against hard surfaces.

Applications of Membrane Switches

Thanks to their impressive functionality and seamless integration with numerous electrical components, membrane switches have found their way into varying industries. They include;

  • Remote Controls: Due to their effective input interface, they are widely exploited in TV, audio systems, and set-top box remote controls.
  • Video Gaming: In the gaming industry, they are prominently employed in gaming controllers and keypads due to their high sensitivity and tactile twist.
  • House Appliances: The majority of modern appliances found in your house today utilize membrane switches in their control panels. They include microwaves and washing machines.
  • Mobile Devices: Membrane switches also find great usage in mobile devices such as cell phones and certain smartphones. They are primarily used in power buttons and volume controls.
  • Medical Devices: In the medical and healthcare industry, membrane switches are incorporated into distinct diagnostic and patient monitoring systems.
  • Security Systems: Membrane switches are also quite prominent in distinct security systems including security doors and alarm systems.
  • Point-of-sale Systems: Owing to their reliability, they are often exploited in cash registers and self-checkout kiosks to facilitate easier payments.

At WEPROFAB, we are a trusted manufacturer of membrane switches in China. Whether you want standard size or custom designs, you will get them at competitive prices – contact us now.

More Resources:

Silicone Rubber Buttons – Source: WEPROFAB

Membrane Switch – Source: IQS DIRECTORY

Membrane Switching Mechanism – Source: WIKIPEDIA

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