PCB MEMBRANE SWITCHES

WHAT ARE PCB MEMBRANE SWITCHES?

PCB membrane switches combine all membrane switch technologies in one device. A PCB membrane switch can be a support panel for the membrane overlay or supply the electrical pathways.

PCB stands for “printed circuit board” and is typically made of copper clad cloth or fiber material infused a resin material. FR-4 is by far the most common material used today. The board with copper on it is called "copper-clad laminate.” The cloth or fiber material used, resin material, and the cloth-to-resin ratio determines the laminate's type designation (FR-4, CEM-1, G-10, etc.) and as a result, the characteristics of the laminate are produced. An acid resistant mask is screen printed on the copper clad and the exposed sections are etched away using acid. The exposed copper pathways are plated with various metals to protect the copper from corrosion. Gold plating is required on many PCBs in critical applications, such as air bag switches for the automotive industry.

FLEX MEMBRANE SWITCHES

Flex membrane switches are a close relative of the PCB membrane switch. Flex membrane switches use thin dielectric materials in place of the fiber material inner layer. One advantage of this technology is the ability to die cut parts which reduces cost on parts and tooling. Flex membrane switches will require a support panel similar to that of a silver circuit membrane switch.

Both PCB and flex membrane switches have several advantages over a silver printed circuit, but generally at a higher cost. The advantages over silver circuits are:

  • Lower electrical resistance/higher conductivity.
  • Hard soldering vs. epoxy silver paste to attach components.
  • Soldering many components types using automated equipment.
  • Finer pitch possible.
  • Plating options, e.g., gold.
  • Can be used in extreme environments.

The array of components that can be soldered to a PCB membrane is vast indeed. These components include, but are not limited to LEDs, resistors, connectors, both SMT and though hole, LCD and LED displays, and speakers. The addition of a daughter board can add even more design flexibility and can connect directly to the PCB membrane switch.

BACKLIGHTING YOUR PCB MEMBRANE SWITCH APPLICATION

If you would like to backlight your application, the membrane switch construction would incorporate either light guides or LEDs for uniform lighting.  Other options for backlighting are fiber optic backlighting and EL backlighting.  Depending on the requirements of your application such as thickness preference, shape, environmental exposure, and other unique specifications, the backlighting options would vary and be selected specifically to fit the function of your device.  Using the latest LED powered lighting can reduce cost and reduce power used by a device.  Since many devices today are portable, this backlighting solution is more relevant than ever.

A variety of applications that use backlighting solutions are: remote controls, laboratory equipment, airplane dashboards, medical devices in dimly lit operating rooms, consumer appliances, such as coffee makers and microwaves, laptop keyboards, and many other applications that we all come in contact with daily or sporadically.

We have various backlighting samples that you can evaluate and consider for your application.  Please feel free to submit a sample request  and we’ll send you a variety of useful samples and tools you can experiment with for your application.

Silicone rubber keypad integrated with flexible printed circuit
5-button membrane switch, with integrated window, designed and manufactured for Bunn-O-Matic
12-button, embossed key, membrane switch with integrated window, designed and manufactured for Baxter Healthcare
10-button membrane switch, with mechanical rotary-dial cut out, designed and built for CareFusion

NEED HELP WITH YOUR NEXT PCB MEMBRANE SWITCH PROJECT?

SCHEDULE A MEETING WITH US TO RECEIVE TOP-TIER ENGINEERING AND DESIGN SUPPORT.

Download your free PCB membrane switch design guide now!

Hand Opening Microwave

OUR TEAM OF ENGINEERS STAND READY TO ASSIST YOU

TOP