A tactile membrane switch embeds a metal elastic dome or silicone rubber keypad combined with conductive carbon pills molding into keys or buttons appropriate elastic response. As plastic overlay for this membrane switch, under this top overlay , there is many metal domes to enhance its tactile properties for its keys or buttons. These domes can be made of conductive materials, maybe it is designed into arch with four feet so that being convenient for user to press down. When user press down one dome, Dome contact with underneath circuit layer, close electric circuit. Release the dome, circuit disconnected. By dome’s tactile property, it will control circuit connection and disconnection completely. In most applications for membrane switch field, such tactile membrane switch is most !
PET and PC overlay , underneath which, embeded elastic metal domes,when you press these buttons on this layer, you can have a good elastic feeling. But the top layer is decoration layer, on which, custom pattern, number, letters and screen printing method. At last it is pressed by heat and become arc shaped decoration overlay !
The ideal overlay thickness for a membrane switch is between.006 and.010 for optimum tactile feedback. These thickness levels have the strength to satisfy your needs and the sensitivity to offer a high-quality tactile experience.
They are typically made of stainless steel with nickel-, silver-, or gold-plated metal domes. The chosen plating is determined by the switch’s conductivity requirements, which are based on electrical resistance. Nickel serves as the benchmark, while gold reduces resistance. The majority of metal-plated domes are used with screen-printed silver circuitry. Usually, only copper flex or PCBA-based designs get gold plating.
The requirement to match the material of the underlying circuit can also influence the plating choice. As an illustration, gold on gold is a popular strategy to enhance electricity conductive. This type tactile membrane switch realize its tacticle properties by metal tactile dome.
Assembly for Tactile Membrane Switches, Metal domes is available in many dimensions and forms, with actuation forces ranging from 180 to 700 grams. The most typical weight is 340 grams.
A layer of silicone rubber keypad is made with designated mold, on which, pattern, letter, and number is screen printed. Therefore, at the back side of these buttons, there are many conductive carbon pills. This will form into a single dome conductive layer. Add lower conductive layer, that is PCB or FPC printed circuit. Same to the dome and PET and PC overlay functions.
This silicone rubber keypad is very soft and elastic, it is so softer than metal dome. such designed overlay is also for tacticle membrane switch’s selection. For example, TV remote controller, Interphone, Caculator and Inspection and testing equipments, these will use silicone rubber keypad overlay largely.
In Summary, No matter the upper circuit layer is plastic and metal domes together or rubber keys and buttons control panel, they must put on the flexiable circuit board or Rigid PCB assembly board. And work with them togehter ! that is a finished tactile membran swith !