Screen Printed Flex Circuits Pinouts for membrane switch keypads

The schematic or pinout of a membrane switch may be specified by the customer, but if it is initially unimportant to the customer, then the pinout should be unspecified. As with any circuit layout, more freedom will allow us to produce a more efficient layout. This has the advantage of shorter development time and a simpler circuit layout, which could nominally affect switch reliability. Membrane switches can be designed with a common bus or in a matrix. Matrix layouts are desirable for membrane keyboards with many keys to simplify the interconnect.
Membrane switch keypads ESD/RFI Shielding circutis
Several options are available for shielding membrane keypads. The most common are printed carbon, printed silver, and aluminum foil. From a functional standpoint, the main difference among these materials is their conductivity. Either carbon or silver can be printed on the top of the top circuit to act as a shield. These shields have the advantage of not adding any additional layers to the switch construction. Carbon shields are less expensive than silver shields. Silver is usually printed in a grid pattern to reduce cost. A layer of aluminum foil can also be added above the top circuit. This material is the most conductive shield available. However, it does add two layers to the switch construction. The shield is usually connected to the ground through the connector, or by means of a tab with a slot for a fastener. The customer should express their shielding requirements in Ohms per square inch. The entire product packaging must be considered when specifying shielding requirements.
More information visit:www.jcftechnology.com