What is a Dome Switch Keypad?

Dome switch keypads uses two circuit board traces in conjuction with a metal dome. Metal domes typically made of stainless steel, are momentary switch contacts that provide tactility or “snap” and become normally-open tactile switches when actuated on the circuit.

The main advantage of dome switch keyboards is the tactile snap or feedback when actuated. When pressing the key, the user realizes they have actually actuated the switch due the feel and sound feedback received from the dome.

Another major benefit of the dome switches are the the long lifespan and reliability. Standard dome switch keyboards are now rated from one million to even five million cycles.

Domes can also be plated in other metals such as nickel, silver or gold. There are also many different shapes (four legged, triangle, round, oblong) and sizes of the domes; as well as a multitude of actuation forces from low force to high force. CSI can work closely with you in choosing the right dome to ensure best performance and tactile response for your application.

Understanding Dome Actuation Forces:

Actuation force is the amount of force required to make the dome snap. Or in other words, how much force is required to change the dome from the open position to the closed position. Dome actuation force is typically measured in grams.

Internal Venting for Dome Switches:

A critical aspect to keep in mind when designing a dome switch keypad is internal venting. When the dome is actuated, air is trapped underneath the dome with nowhere to go. It is therefore recommended that venting is incorporated in the membrane switch design. Not properly venting the dome will result in poor tactile response, key failure and potential issues with air entrapment under the membrane surface.

How Do I Choose the Right Dome for my Membrane Switch?

The CSI engineers will work very closely with you in deciding which dome is best for your application. Typically the decision is based on the force of the dome (how soft or hard of a press it takes to actuate the dome) and is extremely subjective. CSI can mock up different sample keypads with different dome options so the customer can decide through a more “hands-on” approach.