Knitter-Switch – membrane keypads & rubber keypads
Membrane keypads offer a unique combination of features to enable fast and simple supply of customer specific keypads. High quality products, designed in Germany and manufactured in Asia to ensure competitive prices, are backed up by local design and sales support to ensure fast and accurate communications and rapid delivery of each customer’s requirements. Switches are available in flat, poly-domed and metal-domed types, giving a variety of levels of tactile feedback, and life expectancy in excess up to one million operations. All Knitter-Switch membrane keypad designs are tested for resistance to surface scratching, thermal shock, electrical ratings and operating lifetime.
Silicone rubber keypads are manufactured from elastic, non-toxic silicone rubber compounds. Silicone keypads are processed from compression or injection molding. The result is an economic and reliable keypad for small, medium and large production runs. Silicone keypads can be integrated with printed circuit boards or flexible circuits and have excellent resistance to temperature and aging.
Technical properties of membranes
General design
»Flexible graphical overlay, Polycarbonate
»Thickness : 0,075mm … 0,50mm
»Metal-dome connects printed circuit on lower circuit (silver ink printing or photolithographic method)
»Printed circuit connected to the tail
»Simple connection to the PCB via connector (e.g. ZIF)
»Adhesive on the back for assembling on the device
»Remove back paper, connect to PCB, stick on device – finished!
Overlay
›Polyester or polycarbonate foil
›Withstand mechanical demands
›Formability (embossing)
›Different overlay structures (textured, matt and shiny)
›UV resistant overlays
›Cut-outs and windows
Printing
›Different colours and symbols
›Colours can be printed in covering and shining through (hidden LED’s)
›Backside printing for higher durability
›Silkscreen printing, more colours -> more frames -> higher tooling costs
»Advantages of touch systems
›Fast cleaning with disinfecting substances
›Dust and splash water resistance can be realized easily
›Noiseless and durable due to “no moving parts”
›Can also be used with medical gloves
›High resilience, no caps etc. can be broken or scratched
