What is a Membrane Switch?
Things We Touch Everyday
Human Touch Interfaces
The easiest way to understand what a membrane switch does is to reference an all-time favorite device-the microwave. A membrane switch on a microwave is the buttons—the human interface layer—that communicate to the microwave that you’d like to reheat your food for one minute.
The Membrane Switch Design
The switch is the button you touch that sends an electrical signal to start cooking your food.
The Membrane Circuit
The membrane is the circuit behind the touch switch. Circuits are stiff or flexible sheets printed with a conductive material to send a signal to start a process, such as heating food for 30 seconds.
Spring Touch domes, LED and fiber optics add functionality to the circuit interface. These are added with automated placement in the manufacturing process that solders them in place.
How Are Membrane Switches Made?
Common Membrane Switch Design
A membrane switch consists of various layers laminated together. The typical membrane switch includes a graphic overlay, adhesive, retainers, spacer, printed circuit, rear adhesive, and tail filler.
Conductive materials and graphic inks are printed or laminated onto the surface of these plastic films. They function by temporarily closing or opening an electric circuit.
The compact and efficient construction of membrane switches makes them suitable for various applications such as household appliances and industrial equipment interfaces.
Video simulation of membrane switch construction.
Graphic Overlay Printing
Printed Circuit
Dome Placement
Diecutting & Finishing
Two Circuit & Shielded Membrane Designs
Challenging environments or more stringent specifications may require a two-circuit switch. A copper and polyimide construction, often called the “Kapton” circuit design, offers an advantage over current carrying capacity and better moisture resistance.
Explore more Membrane Switch construction possibilities. Request a capabilities brochure and a membrane switch design guide, or contact us for support.
What Are the Membrane Parts and Options?
Graphic Overlay
The graphic overlay is the outside interface we see as a user. It’s the human-centered design interface or HCDI. The surface you touch allows the button or input to send an electrical signal to a circuit board to enact a process. You can choose Graphic overlay printing in single or full-color.
Graphic Adhesive
Applying graphic adhesive to the back of the graphic overlay allows the overlay to attach to a Dome Retainer securely. The adhesive is an acid-free, permanent industrial 3MTM adhesive that withstands various temperatures and humidity variances.
Dome Retainer
The dome retainer is a separator creating a barrier from the graphic adhesive and domes to function when pressed.
Circuit Spacer & Tail Filler
The circuit spacer provides space for both LEDs and Domes on the circuit. Tailer fillers add additional strength and support to prevent kinking and circuit breakage. The spacer also provides benefits for LEDs allowing the distribution of light emission.
Circuit
The circuit is the printed layer, in many instances, on a thin sheet of film. The circuit connects Touch Domes and LEDs to the device’s circuit boards and motherboards. Commonly circuits are screen printed on a transparent film sheet with electrically conduction inks.
Rear Adhesive
The rear adhesive is the last layer of the membrane. The adhesive layer provides critical functionality by sealing the circuit and allowing placement onto the device.
Frequently Asked Questions
Which type of tactile feedback dome works best in a higher heat environment?
Stainless Steel domes will out perform a polyester tactile dome in this situation.
Can you surface mount LEDS on my Membrane Switch?
Yes. We do it all the time!
What are the quantities required for prototypes and production?
For prototyping we typically do 5 to 10 parts or a lot-fixed number.
Production quantities vary from five to thousands.
To make sure you receive the highest quality parts, we require that we receive final approval from you before production commences. Our Design Team has the ability to create your product from an idea, drawing, picture, and more.
Is tactile feel needed on any of the dome types?
We offer both metal domes, which can be either stainless steel or gold plated, and poly domes. Tactile feel is not required and open to customer preference.
What are the different types of termination you offer?
AMP, Berg, Nicomatic. Different centers and of course open contacts for ZIF application.
What are typical metal dome sizes?
8MM, 10MM, 12MM, 14MM, 20MM
What is the actuation force of domes?
Dome force ranges from 85 grams to 700 grams.
What is your lead time?
Because we manufacture custom products our “lead times” are dependent on volume and complexity of the project. We make every effort to deliver your part the way you want it, when you want it.
How robust is an EL lamp over a stainless steel dome incorporated in a membrane switch?
We have tested our EL lamps up to 1,000,000 cycles without showing any degradation or failure.
Request a Quote Online
Our team can get you started on your next project.
The Technomark design and engineering team will work with you to fully understanding your needs, from collaboration, design verification, sourcing the best materials, prototyping, and manufacturing to your exacting standards.
Before delivery, parts are visually inspected and electrically tested for functionality.
Customer Support
Technomark, Inc.
11574 Encore Circle
Minnetonka, MN 55343
800.352.3493
952.912.1700
