July 2022 - Hallmark Nameplate

When you work with a corporate manufacturing facility that mass produces, they often throw a lot of big words around without explaining anything.

That can make the design and selection process very overwhelming and confusing.

So, we wanted to take the time and walk you through the basics of a membrane switch so you understand what you are spending money on creating.

In this article, we will discuss:

What are membrane switches?
The anatomy of a membrane switch
Applications of membrane switches
Benefits of membrane switches
The differences between tactile and non-tactile switches
Types of tactile switches

Let’s dive in!

What Are Membrane Switches?

Membrane switches are electrical switches for turning a circuit on and off. It differs from mechanical switches made of copper and plastic parts.

A membrane switch is a circuit printed on PET or ITO. The ink used for screen printing is usually copper, silver, and/or graphite filled, and is therefore conductive.

Membrane switches are user equipment interface utilities that allow for the communication of commands from users to electronic devices. Membrane switches are one category of interface utilities alongside touch screens, plastic keyboards, toggle switches, and many other kinds of control systems.

Interface utilities can be as simple as tactile switches for controlling lighting, and they can be as complicated as membrane keyboards and switch panels for use with computers.

Anatomy of Membrane Switch

A membrane switch typically has four or more layers. The top layer of a membrane switch is the graphic interface between the user and the machine.

The other critical layer is a printed circuit or a flex circuit made of copper and polyimide material. There is the top circuit layer and a lower circuit later with a circuit spacer in between.

The layers are assembled using pressure-sensitive adhesives. A printed shorting pad or metal dome that stands on legs can create contact between the two traces.

Applications of Membrane Switches

There are so many ways membrane switches can be used in our day-to-day lives.

Some examples of where you can find membrane switches are:

Microwave oven panels
Air conditioner control panels
TV remote controls
Medical equipment
Gym machine controls

The tactile feedback of keys can be provided by embossing the top PET layer or embedding metal snap domes, polyester domes, or forming the graphic layer.

Benefits of Membrane Switches

The benefits of membrane switches include:

Ease of cleaning
Sealing ability
Low profile
Reliability
Durable
Improves safety

Membrane switches are used with other control systems, such as touch screens, keyboards, and lighting.

Sometimes they are complicated like the membrane keyboards and switch panels in mobile phones and computers.

Membrane Switch Designs

Design membrane switches to meet your environmental considerations. Additionally, internally vent and seal switches to protect your equipment from contaminants.

Membrane switches can also be provided with or without terminating connectors as well as:

LED Indicator Lights
Backlight (LED, fiber optic, EL)
Chemical and Weather Resistant
ESD/EMI/RFI Shielding
Domes
Embossing
Various connector configurations

When you create your membrane switch you get to customize every aspect to your applications’ needs.

Embossing Options

There are two main embossing options to choose from.

The standard pad is when the full key is raised. You can choose a round or rectangular shape to match the underlying key.

The rim option is when only the perimeter is raised. The recommended size is a rim width of at least .05″ and a height of no more than 1.5-2 times the overlay material’s thickness. A corner radius of at least 0.031″ is also recommended with spacing between the emboss features of at least .125″.

Another option is dome emboss which offers feedback even for a non-tactile switch. Speaking of dome…

Dome Types

When choosing a dome, there is a wide ray of materials and sizes to choose from. We recommend using metal for its durability.

The sizing options include:

6MM
8MM
10MM
12MM
16MM
20MM

You can also create a dome that is oblong, a thin oval shape.

Circuit Materials

There are three options when choosing circuit materials.

Silver is the most common choice due to its simplicity and cost-effectiveness. Silver conductive ink is printed onto the polyester circuit material.

The copper flex circuit is popular for complex circuitry. You can solder several components to the circuit and can accommodate any of your applications’ needs.

A popular option for complex designs is a rigid printed Circuit board (PCB). Conductive silver ink is printed right onto a polyester layer, then a contact surface of etched plated copper is enclosed in a PCB inside an epoxy for insulation. A dielectric layer is added for further protection.

Connector Options

The connector is responsible for attaching the switches’ sensors to the circuit board. There are five connector options:

Bare Tail – These interface to .100″ center zero insertion force (ZIF) or low insertion force (LIF) style connectors
Latching Female Connector – These interface to .100″ center latching headers
Latching Male Connector – These interface to .100″ center latching headers
Plain Male Connector – These interface to .100″ center female headers
Plain Female Connector – These interface to .100″ center and .025″ square-posted headers

Choose wisely, because a subpar connector will lead to unreliable switches.

Backlighting Options

Backlighting is another way to make it easier for the user to find important buttons. there are three main backlighting options to choose from:

Fiber Optic – This cost-effective option is two layers of woven fiber-optic cloth that emits light.
Light Emitting Diodes (LED) – Another affordable option but is not an effective indicator light. You can choose between blue, green, red, white, and yellow and select an intensity level.
Electroluminescent (EL) Lamps – It relies on phosphors that convert electrical energy into light. It is highly efficient and minimizes energy waste. This is the perfect option for buttons that aren’t left on for long, because they do decay.

Your manufacturing facility partner can help you determine which option is best for your application.

Shielding Types

This protects the switch from damage from electromagnetic interference (EMI) and electrostatic discharge (ESD).

There are three different ways shields can be terminated:

Connector – The on switch tail can also terminate the shield.
Conductive adhesive – Electrically conductive adhesive can be used to connect.
Tab – The switch’s tab can be connected with a stud of standoff located on the metal enclosure or backer.

There are also three types of shielding:

ITO clear conductive shield – This type can be terminated with conductive adhesive
Foil shield – Can be terminated to a tab
Connector – The pin on the switch can also terminate the shield

Additionally, when creating a membrane switch you can select if you want to create a tactile or non-tactile switch.

The Difference Between Tactile and Non-Tactile Switches

The differences between tactile and non-tactile switches are crucial to know but simple to understand. As the name probably suggests, tactile switches provide tactile feedback. Let’s dive into what this really means.

Tactile Switches

A tactile switch is an on/off electronic switch that is only on when the button is pressed, or if there is a definitive change in pressure. Another way to consider it is as a momentary make-or-break switch. As soon as a tactile switch button is released, the circuit is broken.

The main area of tactile switches is tact switches. Tact switches are tactile electromechanical switches for keyboards, keypads, instruments, or interface control-panel applications.

Tact switches react to user interaction with the button or switch when it makes contact with the control panel beneath. In most cases, this is usually a printed circuit board (PCB).

Types of Tactile Switches

There are many different kinds of electronic Tactile Switches; there is a variety to select from. Some types that are available include:

Standard
Illuminated
Sealed
Key Tops
Surface Mount
Hinged

At Hallmark Nameplate, we are here to assess your needs and create the best, most functional membrane switches to suit your needs, with your budget in mind. Our offerings include a range of sizes and styles.

Applications of Tactile Switches

Typical tactile switch applications include low power, miniature devices, digital switching, and if operator feedback is required (with a switch confirmation coming from the switch being depressed).

Tactile switches are internally vented. As a result, you can expect a complete seal on your membrane switch.

Additionally, our tactile switches are capable of more than one million actuations, making your options and functionality virtually seamless.

Non-Tactile Switches

The most reliable and economical membrane switch is the non-tactile type. However, they do not give the user direct feedback from the switch.

Using an LED indicator or display change can sometimes overcome this drawback. Non-tactile switches also have the advantage of easily creating custom shapes and sizes of the active keypad areas.

Non-tactile switch types feature a robust construction. They’re completely sealed from the external environment. They are also more versatile than tactile switch types, with more than five million actuations.

Create Custom Membrane Switches With Hallmark Nameplate

If you want to create high-quality custom membrane switches, then you have come to the right place. We strive to always exceed our customers’ expectations by walking you through the entire process to make sure everything is perfect.

At Hallmark Nameplate, you can rest easy knowing that your product will be developed by our in-house design and engineering staff from concept to completion. Request a quote today!

Do you ever sit down on a metal chair and feel a shock run through you? It’s not a pleasant feeling.

Now imagine that shock going to your electronics. You can probably imagine how bad that could be.

This is called electrostatic discharge.

Now you may be wondering: what is electrostatic discharge? Keep reading to find out what it is, the damage it causes, and how you can prevent it.

Let’s dive in!

What Is Electrostatic Discharge?

Electrostatic discharge is what happens when the flow of electricity between two objects that are electrically charged is suddenly shorted by contact between those two objects. This happens because there has been a buildup of static electricity between the two objects.

Static electricity can build up between objects due to tribocharging or by electrostatic induction. Usually, when electrostatic discharge occurs, there is a visible spark of electricity between the two electrically charged objects that were brought together.

In fact, electrostatic discharge can produce amazing electrical spark shows. In the natural world, lightning that is accompanied by the sound of thunder is a large electrostatic discharge event. Other times, electrostatic discharge may produce no sparks or noise at all.

However, even when it is unnoticed, electrostatic discharge can still cause damage to electronic devices.

Dangers of Electrostatic Discharge

Industries that use electrical devices have to constantly be on guard against electrostatic discharge. It can have harmful effects on a variety of industries.

Electrostatic discharge can cause explosions in natural gas, vapors of auto fuel, and coal dust. Additionally, it can destroy integrated circuits. Because of the dangers to products and instruments from electrostatic discharge, the manufacturers of electronics have established areas in dangerous environments that are static-free. These are electrostatic-safe areas.

These areas are created by taking measures to prevent charging and remove static, such as:

Grounding Human Workers

Grounding workers prevents electrostatic discharge in sensitive environments. The use of wrist straps, footwear, and grounding mats allows workers to discharge any static electricity safely, reducing the risk of accidental sparks that could cause equipment damage or even explosions.

Supply Antistatic Devices

Antistatic devices are specifically designed to prevent the buildup and release of static electricity. These devices include antistatic wristbands, mats, and clothing that can safely dissipate electrical charges. Additionally, using ionizers in the workplace can neutralize static in the air, creating a safer environment for electronic components and reducing the risk of damage from electrostatic discharge.

Avoid Highly Charged Materials

Certain materials, such as plastics and synthetic fibers, are more likely to accumulate static electricity. In sensitive areas, it’s important to minimize the use of these materials or treat them with antistatic coatings to reduce their ability to hold a charge. Selecting materials with lower static generation properties can further reduce the risk of ESD.

Control Humidity in Environment

Maintaining optimal humidity levels is another effective strategy to prevent electrostatic discharge. Dry air is more conducive to the buildup of static electricity, while higher humidity levels can help dissipate charges more quickly. Installing humidifiers or monitoring air moisture levels can help maintain a balanced environment, preventing static accumulation and protecting sensitive equipment.

Following these steps will help decrease the chances of electrical discharge.

How Does Electrostatic Discharge Affect People?

The voltage of an electrostatic discharge can vary depending on what is involved. For instance, getting a shock from your carpet can range from 1,500V to 35,000V. Faulty electrical equipment can produce similar shocks in this range.

A person feels pain at 3,000V, meaning these shocks can result in someone being hurt temporarily. While not usually harmful, it can signal potential underlying issues.

What Is Tribocharging?

Tribocharging, which is a common cause of static electricity, can be accomplished through a variety of means. Walking on a rug is an example of tribocharging, as it brings two electrically charged materials (the human and the rug) together, then quickly separates them.

Rubbing a plastic comb on dry hair is another example of tribocharging that produces static electricity. Rubbing a balloon against a piece of wool, getting up from an upholstered car seat, and taking certain types of plastic packaging off of a product all generate static electricity through tribocharging. When one of the tribocharged items touches another charged item, a spark may be seen or felt, and electrostatic discharge occurs.

How Does Electrostatic Discharge Occur?

Electrostatic discharge can also occur via electrostatic induction. This happens when an electrically charged object is near an object with conductive properties that is not grounded.

The charged object creates a field of electrostatic energy that redistributes the electrical charges on the surface of the non-grounded object. When this happens, the un-grounded object now has areas where there is an excess of positive and negative charges on it.

Electrostatic discharge may occur when the un-grounded object touches something with conductivity. For example, the surface of Styrofoam cups causes electrostatic induction on nearby sensitive objects. Electrostatic discharge may occur if they are touched with anything made of metal.

Most spacecraft are prone to electrostatic discharge because of charged particles pinging against them. This causes increased charging on the surface, making them prone to electrostatic discharge.

Damage to Electronic Equipment

The most dangerous part of electrostatic discharge is the spark. It can cause minor pain to people and severe damage to electronic equipment. Fires and explosions may occur in areas with charged air and combustible gases and/or particles.

However, even without a spark, damage from electrostatic discharge can occur. Even tiny amounts of discharge can damage electronics. This can either break them completely or make them prone to degradation over time. This affects their long-term reliability and performance.

Types of ESD Events That Cause Electronics To Fail

Discharge to Electronic

This typically occurs when an electrostatic charge comes from a person to the device. For example, if they walked across the room and accumulated electrostatic charge and then began working on the device. Similarly, damage can occur if you use a charged conductive tool to work on an electronic during assembly.

Discharge From Electronic

Your electronic device can accumulate a static charge during manufacturing when rubbed against a surface or shipping in its packaging material. When things are mass-produced with automated assembly, it can lead to a higher chance of component failure.

Field-Induced Discharge

When an object becomes electrostatically charged, it creates an electrostatic field. When a device enters the field and is grounded, it accumulates charge. If it is then removed and grounded again, ESD may occur

Protecting Against Damage

Because electronic discharge damages so many electronic components, it is necessary to protect against it. Protect sensitive materials during every process including:

Manufacturing
Storage
Shipping
Assembly
Consumption

An effective and important method of preventing electrostatic discharge is grounding. Ground regularly and routinely check that all components are properly positioned.

While electrostatic discharge is a natural phenomenon, it can damage electronic equipment, hurt humans, and even damage workplaces and cities. Minimize or prevent possible damage with the proper safety precautions in place. This is good for the safety of all.

Keep Your Devices Safe From Electrostatic Discharge With Hallmark Nameplate

If you have any questions about electrostatic discharge, contact Hallmark Nameplate. We maintain an ESD-Safe environment by not having an automated, fast-moving production line. This allows us to test and safely assemble our products for our customers.

Give us a call or visit our website and speak with seasoned professionals about our electronic assembly services.