How does it feel to type on your computer keyboard? The sound of the keys, the quick feedback for every press received as a response for what you type – it’s an experience! The physical feedback you receive while typing on the keys is due to its tactile response!
Switches that provide a physical response when pressed on the switches are typically called tactile switches. The simple membrane switch construction allows this interaction easier.
On the other hand, if you press a switch on a medical device like a cardiac monitor, it may not provide a so-called switchy response! These switches do not have a tactile response, it is a simple switch construction model. The tactile feedback differentiates between the two forms of membrane switches.
Let’s learn about these two forms, from their construction to their uses/applications.
Construction, Purpose, and Uses
Tactile membrane switches
A tactile switch comprises four main components – graphic overlays, domes, conductive tracks, and a printed circuit. The graphic overlay is the front panel display of the device, and it lays as the platform for direct interaction. The switch and display are operated and controlled using these overlays.
When a user press on a switch, the dome layered underneath the overlay provides a switchy feel. The most common material choices for domes are metals. Apart from the metal dome, the plastic/PET dome is an alternate option, used to provide innovative tactile feedback! The actuation force to trigger an action is less for plastic than for metal domes.
The domes come in any shape and size, depending on the device’s functioning.
For industrial settings, larger domes are used because the users wear gloves and hence, need higher force and stronger tactile feedback. But, in the case of nursing settings, a dome with lighter force is a fit, as parenting these switches will be delicate.
So if the user makes contact with the switches, the domes are pressed, and the conductive footprint (track) pushes down and comes in contact with the printed circuits. This will trigger an action like the device turning on when a user press the On button.
If released, the dome springs up and disconnects the conductive track from the circuit layer – making the action stop. If pressed again, the process works again, like the user pressing the On/Off button again to turn off the device.
The metal domes are made of stainless steel, vented internally to protect them from outside particles. The venting gives more life to the domes, making the membrane switch durable. Tactile switches can be activated, at least one million times.
- To trigger a momentary action
- Activates upon pressing the switch
- If released, the switch disconnects & the action stop
Uses or Applications:
- In PCBs of various electronic and electrical components
- Electronic equipment in Aerospace, aviation, and defense industry
- Embedded inside gamepads to enhance the gaming experience
- Computer and laptop membrane keyboards
- Appliance interfaces in commercial, industrial, and medical industries
- Quick & reliable tactile feedback
- Low weight design
- Many actuation force options are available
- Fully ruggedized design
- Suitable for various applications
Non-tactile membrane switches
In non-tactile switch construction, there won’t be a dome component. Hence, the switch won’t provide a physical reaction if a user press on it. A conductive pad replaces the metal domes, which are not in contact with conductive tracks.
As you can see, there is enough space between the middle two layers and no point in triggering feedback. Due to this reason, an auditory signal or visual display response is triggered for every press, which provides feedback to users and helps them know the action fulfillment.
- To activate things without real buttons
- Provides a smooth user experience with a sleek design
- Backlights or sounds provide feedback for user interaction
Uses or Applications:
- Gaming controllers & devices
- Medical devices
- Vehicle dashboard controls
- Consumer electronics with backlight LED switches/buttons
Non-tactile switches are used alongside tactile switches in a supportive role. A common use case – is the use of non-tactile switches on inputs as backlights. Another scenario is using non-tactile buttons for controls and tactile switches for inputs.
- Cost-effective solution
- Rugged design
- Customizable based on any requirements
- Long life cycle – can activate up to 5 million times
- Lean design
- Dust & moisture resistant
- Can incorporate alongside complex user interfaces
- Embedded sensory feedbacks
Should I choose tactile or non-tactile membrane switches?
Not every device requires tactile feedback to impress the user.
Consider a vehicle dashboard, users do not require tactile feedback for controls; led or sound-triggered feedback will do it. If you are from the transportation industry, you obviously will go with this decision, as users never complain about receiving an actual response for the controls.
As a manufacturer, consider these technical factors that will influence the membrane switch construction. Always consider the environment where the device is applied.
Panel material thickness: Users won’t have a good experience if the panel thickness is high. With a sleek panel, the experience will be most welcoming.
Embossing: Embossing height of 0.3mm to 0.5mm will provide a perfect tactile feel.
Dome thickness: If using thicker domes, increase the tactile dots, and it will improve the user experience.
Force of dome attached: Adding an extra layer below the overlay will prevent the dome from accidental movements.
Mold choice: This underrated factor affects the user experience. Stainless steel molds work perfectly than CVC tooling membrane switches. A soothing feel is the last thing a user need for reliable device interaction.
That’s it – With a basic understanding of the construction, purpose, uses, and influencing factors, you can make an appropriate switch technology for your device interface.