When it comes to membrane switches, you basically have two options: a flat panel membrane switch or a dome switch membrane keypad. Dome switch keypads uses two circuit board traces under a flexible keypad using a metal dome. Metal domes (metal snap domes, or tactile metal domes), made of stainless steel, are momentary switch contacts that, when used in conjunction with a PCB, flex circuit, or membrane, become normally-open tactile switches.
The main advantage of dome switch keyboards is the strong, crisp tactile snap or feedback. Because they are typically made of metal, they produce a crisp snap when pressed or actuated. In addition to giving tactile feedback (the user realizing they have pressed the key), the dome also assists in reducing typing errors and subsequently improving accuracy.
Another major benefit of the dome switches are the the long lifespan when compared to other styles of keyboards. Standard dome switch keyboards are rated up to one million to even five million cycles.
Furthermore, dome-switch keyboards can be plated in a variety of metals, including nickel, silver or gold. There are many different shapes and sizes of the domes. Additionally, there are different 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.
Typical Dome Shapes:
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). CSI can also mock up different sample keypads with different dome options so the customer can decide through a more “hands-on” approach.
To recap, dome-switch keyboards are a hybrid of flat-panel membrane and mechanical-switch keyboards. They offer strong tactile feedback, a long lifespan, and they can be plated in a variety of different metals. A variation of dome-switch is the scissor-switch, which is often used in laptops and similar electronic devices. Hopefully, this gives you a better understanding of dome-switch keyboards.