What are Membrane Switches? Individual2 years ago - Cattle - Chennai - 633 views
What are Membrane Switches?
Membrane switches are a type of human-machine interface characterized by being constructed from several layers of plastic films or other flexible materials. 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 a vast array of applications such as household appliances and industrial equipment interfaces.
Membrane switches have been around for about five decades. In the early 1970s, the first membrane keypads were introduced. They were made up of polycarbonate plastic films printed with copper or silver infused ink creating the electronic circuit. These were composed of two conductive layers with one spacer in between. The products were inexpensive but threatened by problems such as degradation and cracking of the polycarbonate film and missing tactile feedback.
The next iteration solved the durability and quality-of-life issue by changing the plastic film into polyester and adding metal domes into the design. However, membrane switches have not been readily adopted since, during that time, the huge personal computer market was dominated by mechanical keyboards. Mechanical keyboards were preferred due to their more tactile feedback.
Come the 1990s, thinner keyboard keys and membrane switches were used to make more compact and quieter keyboards. By that time, smaller electronic devices were the future of technology. The emergence of appliances and equipment with small electronic components further elevated the need for membrane switches.
Today, the global membrane switch market has a market size of approximately $4.2 billion in 2015 and is expected to grow to $13 billion by 2025. Membrane switches are extensively used in industrial, medical, and consumer goods applications.
Membrane switches are extensively used in a variety of applications may it be domestic, commercial, or industrial. There are other types and forms of user interfaces such as touchscreens, keyboards, switches, and selector knobs. Membrane switches are preferred because of their compact profile, simple construction, reliability, resistance to harmful elements, and low cost. These advantages are further elaborated below.
Thin and compact profile: Each plastic layer of a OCA membrane switch can have a thickness of about 0.005 to 0.040 inches. They typically have three to six layers depending on the design. Even applying the conductive and graphic inks and installing other components such as the metallic domes and EMF screens, the final thickness still results in only a fraction of an inch. This makes them suitable for household appliances and equipment controllers with small form factors.