Membrane Switches
Diagram of a typical membrane switch
Simply said, a membrane switch is a user interface that has flexible switches. Each switch closes a circuit when depressed which immediately opens upon release.
ASTM Membrane Switch Criteria
According to the the ASTM International, an international standards development organization, a membrane switch must meet the following criteria:
- Contain a membrane - a very thin flexible material which gives when pressure is applied.
- Contain a static layer - a non-flexing layer with the circuitry that the switch poles connect to.
- Make direct contact - poles of the switch must meet directly during operation.
- Function as a momentary action - the poles must instantly separate when the switch is released.
- Use low voltage - direct current logic-level-signal circuitry must be employed
Kinds of Membrane Switches
Membrane switches are used for electronic handheld and stationary equipment including home electronics, appliances, medical devices remote controllers and handheld devices. There are many variations of membranes switches and thin panels but the most common are tactile and non-tactile switches. Tactile membrane switches provide immediate feedback to the user; non-tactile membrane switches do not provide tactile feedback and generally have a thinner profile. We will review each of these in the pages that follow.
Membrane switches have a tail that connects to the printed circuit board of the device. Options available for membrane switches include lighting (spot lighting and back lighting), shielding (thermal dissipation, shock absorption, waterproofing, RFI, EMI and ESD inhibition).
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