The most economical and reliable design is the non-tactile membrane switch. Non- tactile membrane switch is flat and has no tactile feedback. However, this design relies on other methods of identifying a feedback or that a connection is made. These include indicator LEDs (visual), LCD screen (visual), or a sound(audible). In other words, an LED light can blink or a beeping sound can be heard when a button is pressed. This type of non-tactile membrane switch has the longest life cycle and reliability.
The other type of membrane switch is the tactile membrane switch. Tactile membrane switch is very popular because it provides a direct feedback to users that a connection is made. One way to design a tactile membrane switch is to dome emboss the keys on the graphic overlay. Although it is a little bit more cost that a non-tactile or flat membrane switch, and requires an embossing tool, it is still a common way to provide tactile feedback when needed. Another design option for a tactile membrane switch is to emboss the upper switch layer or polydome. This will also require an embossing tool. One drawback is that this type of tactile membrane switch provides a milder tactile response and less snap action. Also, it is sensitive to temperature and therefore, high temperature conditions may affect its snap feedback. The best way to get the optimum snap and tactile feedback is to use a metal dome. Metal domes can get expensive especially if the membrane switch has a lot of keys. It is also recommended that the graphic overlays where the keys are, should be full embossed to accommodate the metal dome height. Therefore, an emboss tool may still be required. One thing to consider when using metal domes for tactile membrane switch is that it needs a rigid backing, so that when the metal dome is pressed down, it does not get inverted. An inverted metal dome, is one of the major failures of a tactile membrane switch and is mostly due to the metal dome being bent or deformed when assembling to the plastic housing, and/or pressing the keys when there is lack of rigid support. Please contact KTP for further details on how to correctly design and assemble your tactile membrane switch to your housing. We can be reached at 909-784-6302 or email us at: sales@ktptechs.com.
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