What is a Membrane Switch?
A membrane switch is an operating system integrating key function, indicating element and instrument panel. The membrane switch, also called a Membrane Keyboard or Membrane Keypad, is a custom switch assembly that uses pressure to open or close the conducting path in an electrical circuit. The ultimate purpose of a membrane switch is to serve as the interface between man and machine, enabling an operator to communicate with a piece of equipment, instrument, or machinery. Membrane switches are still consistently utilized as user interfaces for a wide range of products from industrial machinery to medical devices to agricultural equipment. Even the most rigorous of industries can count on proven membrane switch technology to provide a reliable, long-lasting human-machine interface.
How about the construction of a membrane switch?
A membrane switch assembly differs from traditional mechanical switches. Membrane switches are essentially a sandwich of thin layers that are bonded together using pressure sensitive adhesives. The layers of a basic membrane switch construction include: a membrane overlay, spacer, printer circuit, rear adhesive, and tail filler. Other electronic components can be implemented, as well, such as discrete LEDs, backlighting sources, and connectors that make membrane switches easy to integrate into other systems or devices. Each layer in a membrane switch assembly serves a different purpose, and custom features require the addition of specialty layers. Depending on the environment and requirements of the application into which the membrane switch plugs into, the construction can vary.
What materials are used in a membrane switch?
A variety of overlay materials are used in membrane switch applications. The top layer of a membrane switch panel is typically called a Graphic Overlay, is produced by printing on the second surface of clear polyester or polycarbonate film. Circuitry is printed underneath the overlay, is created by screen printing conductive silver ink. For more stringent environmental requirements, the printed silver circuit can be replaced with a copper and polyimide construction. You can contact us for support to explore more possibilities.
| Graphic overlay | PET(F150, V150, F200, V200, XE-series, etc.) |
| PC(0.175mm, 0.254mm, 0.375mm, 0.5mm) |
| Silicone rubber |
| Glass |
| PMMA |
| Circuit | 0.125/0.188mm PET |
| FPC |
| PCB |
| Rear adhesive | 3M467/468 |
| 3M LSE series |
| 3M VHB series |
How to make a membrane switch?
Membrane switches have become an increasingly popular electrical switching solution. A common example is the buttons on a typical microwave.
Most common design features of a membrane switch Include:
l Graphic overlay: digitally and/or screen printed
l Display window: transparent and/or tinted
l Surface finish: gloss, matte and UV hard-coat
l Button: Tactile with metal or polyester domes, and non-tactile feedback
l Embossed: pillow or rim
l LED: indication or backlighting
l Connector: standard .100” connector, or ZIF
Contact us to discuss more membrane switch option for your application.
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