Our short stroke switches
Short stroke switches give the user real tactile feedback with a very low stroke height. As a differentiation from the long-stroke switch, the key stroke for short-stroke variants is between 0.3 and 1 mm. The technological variety in the area of this 0.7 mm is greater than you would expect at first. Short-stroke switches include all types of metal domes, but also the so-called microswitches, which are available in a wide variety of versions.
Metal domes
Metal domes are a cheap and reliable way to generate tactile key feedback with a very low lift height. The product range offered includes metal domes in sizes from 4 mm and up to over 50 mm with compressive forces from 40 to 680 g. There are special shapes, whether round, angular or elongated, available for different applications and some variants have a lifespan of several million operations. Thanks to a central hole, many special versions enable the integration of orientation or functional lighting and special metal domes with new specifications are always being developed on request.
The operation of a metal dome is relatively simple: a kind of arch is bent upwards into the metal plate. This initially does not react when pressure is exerted, but when the force is increased a little, the curvature suddenly gives way and snaps down, so that the typical crackling sound can be heard. By pressing down on the metal dome, it touches the circuit board on which it is mounted and thereby closes a contact that is directly below it on the circuit board. As soon as the pressure that is exerted on the metal dome drops below the pressure point, the metal dome snaps back into its original state and the contact breaks off.
Due to their compactness and low price, metal domes are usually used in membrane keyboards. But they are also processed as contactors under silicone switch mats to give the otherwise rather spongy silicone keyboards a clearer switching feeling. In both cases, the keypads in which the metal domes are used are generally dust and waterproof and are available with or without function LEDs on request.
Metal domes are very easy to apply to a circuit board or layer of a film and, due to their compactness, are also suitable for small keypads and single buttons. Since they are largely shock and temperature resistant, foils with metal dome technology are very often used as small keypads in machines and other technical devices.
Microswitch
In most cases, microswitches are constructed with a lever and a spring, which moves the lever back to its original position after actuation. Only a very small force is required to actuate a microswitch. In addition, microswitches are characterized by the very small distance between the contacts. This is often less than one millimeter, but there are variants with a lifting height of up to 3 mm. The materials used to manufacture the switch withstand thermal loads and mechanical actuation for a long time, which means that they usually have a long service life of several million switching cycles.
The areas of application for microswitches are very diverse and extend to both consumer electronics and industrial applications. They are often used as control switches or in the area of one-finger operation. Through the use of microswitches, the keys get a pleasant and fatigue-free key feeling.
Related Links
Membrane keyboards (Wikipedia explanation)
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