Mechanical Keyswitches vs. Membrane Keyboards

What is a membrane keyboard?

Membrane keyboards are designed so that all the keycaps are positioned above a plastic rubbery membrane which spreads over the entire keyboard. Small contact points on this membrane are imprinted so that when the user presses the keycap the full key travel distance, the metal on the contact point touches the underlying circuit layout, generating the keystroke which is then sent to the computer. Differences in the shape and thickness of the membrane can provide some tactile feedback, however the keystrokes are only generated when the key is fully depressed.

Membrane keyboards are typically inexpensive and subjectively have a softer feel due to the 'sponginess' of the membrane. They are also less durable than mechanical keyboards, with ratings typically in the 2 to 5 million keystroke range. Over time some keys become inelastic and other overly elastic, creating a variance in how much force is required to type throughout the keyboard.

The highest quality membranes use multiple layers, and stabilizing scissor-like devices (like the one pictured at right) to extend the lifespan of the membrane to as much as 10 million keystrokes.

What is a mechanical keyboard?

Mechanical keyboards are more intricate and of higher quality than membrane keyboards. Each key has its own independent keyswitch mechanism that will register when a key is pressed. For example on the mechanical keyswitch at right the keycap rests on top of the blue plunger mechanism which depresses into the unit. In most cases the key is actuated (that is the keystroke is generated and sent to the computer) halfway through the key travel distance. For example, the key may be capable of travelling 4 mm before hitting the bottom of the keywell, but the keystroke is generated after 2 mm. This means that as a touch typist, you need not press keys fully down, reducing the constant jarring action on your fingertips and unnecessary muscle action. In addition, keys often offer increasing resistance after the keystroke is generated, encouraging you to release and move on to the next keystroke. Finally, keys snap back to ready position quicker, allowing for faster typing speeds.

All these features means there is both audible (clicks) and tactile (feel) feedback when you have successfully actuated a keystroke, and whether you are an experienced touch typist or learning to touch type, this will improve your speed, accuracy and eliminate the wasted time spent looking at the screen to ensure that you have typed accurately. About the only person that doesn't benefit from a mechanical keyboard is a hunt and peck typist (a person who hovers their fingers several inches above the keyboard and uses typically only the index finger on each hand to type).

SUMMARY OF MEMBRANE KEYBOARDS VS MECHANICAL KEYBOARDS

MEMBRANE KEYBOARDS	MECHANICAL KEYBOARDS
Less expensive (fewer parts)	More expensive (each keyswitch is a part)
Subjectively lighter touch due to 'squishiness'	Subjectively harder touch due to tactile click which improves typing accuracy and speed
Quieter as there is no audible click when typing	Audible click while typing which improves typing accuracy and speed
Actual force used is usually more than is necessary in order to ensure keystroke is generated	Actual force used is no more than is needed as tactile and audio feedback provides additional indicators of when keystroke is generated
Not durable - 2 to 10 million keystrokes	Very durable - 10 to 50 million keystrokes
Over time keys become softer, harder, and sticky	All keys maintain equal force throughout life of keyswitch (until complete failure)
Keys snap back more slowly, and get slower as keyboard ages	Keys snap back quickly, allowing maximum typing speed

ErgoCanada.com's Guide to Ergonomics is a work in progress. If you have any comments on our existing content or additional material which we could add, please let us know!

We hope you found this general information helpful - for more specific information for your unique situation, we recommend getting an assessment by an ergonomic professional.

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