Product category:
Electrical systems
News Release from: Danielson (UK) | Subject: Tactile switch system
Edited by the Manufacturingtalk Editorial
Team on 26 May 2004
Product redesign raises switch packing
density
By changing methods of manufacture, a tactile switch system can dramatically improve switch packing densities, thereby minimising the potential overall size of key panels.
Danielson, the leading European designer and manufacturer of membrane switches and keyboards, has launched a new tactile switch system that can dramatically improve switch packing densities, thereby minimising the potential overall size of key panels Developed in response to customer demand for ever smaller and more compact membrane products, the new system can be produced in both high and low volumes and at costs that are comparable with conventional membrane products
This article was originally published on Manufacturingtalk on 27 Nov 2003 at 8.00am (UK)
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Traditionally, the principle factor that limits the switch packing density of tactile membrane switches with metal domed inserts has been the method of construction used.
Upper and lower circuit layers are normally printed on a single substrate, with the two circuits being shorted by each metal dome as it is depressed.
Although effective, this technique leads to relatively complex circuit layouts - a situation that can often be exacerbated by the need to provide sufficient separation between circuit tracks; typically, this has to be at least 0.5mm to prevent problems of interference.
To overcome these problems Danielson has redesigned the basic switch construction, moving one of the circuit layers above the metal switch domes and introducing a special retention spacer to locate the dome precisely.
This essentially creates active rather than passive switches, with the upper switch layer pre-contacting the top of the switch domes, which then short onto the lower switch layer once they are actuated.
Although simple in concept, the overall construction requires precise control during manufacture.
Danielson's Marketing Manager, Ben Phelan, explains that, "Like all good ideas, the new switch system is straightforward, but requires specialised manufacturing techniques and extremely high levels of accuracy to achieve the correct results.
In particular, dome location and circuit tolerances have to be carefully controlled".
The new switch system effectively allows the surface area required for each switch to be reduced by as much as 50%, without affecting switch profile or operating life.
In addition, conventional backlighting, LEDs and display windows can easily be incorporated.
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