A few years ago, Apple filed a patent for a keyboard with Force Touch or 3D Touch capabilities. The patent specifically was presented on September 28, 2012 denominated "Ultra low travel keyboard" and that has been granted today.
Said patent shows a keyboard with a sensor for each of the keys that measures the force exerted on the key when the user presses or rests the finger on the key. This would serve to activate indicators information to show suggestions to the user or get feedback on how the user uses the keyboard.
From what I can understand from what is described in the patent, depending on a given pressure On the key, the application under the software layer can "decipher" that pressure thanks to the measurement made by the sensor to carry out one or another action, that is, for example in a word processor if we press any of the the keys may be indicating that that specific letter is capitalized without having to use the shift key at the same time that we press said key
With this sensor below the keys, the keyboard is achieved with an «ultra-short» path, that is, the keys would not be pressed with the normal path, but it would be much lessThis is due to the fact that in a conventional keyboard we must have a greater travel in order to press the switch or mechanism integrated to a contact so that the system registers the keystroke. Because force sensors can register relatively small changes under any pressure.
Recall that Apple has recently launched a new mechanism in your keyboards with a butterfly mechanism instead of the traditional scissor, which makes the travel less, lowering the profile of the keyboard being able to integrate it into portable equipment getting thinner. The next step will be to integrate this technology into those keyboards.