NEWS

Apple patent: distance sensor to replace mechanical keyboard switch

Release time:

2016-10-25 15:33

Nanjing Hua News: On October 20, the U.S. Patent and Trademark Office published Apple's latest patent application, called "Depressible Keys with Decoupling Electrical and Mechanical Functions", which details the use of distance sensors to decouple the mechanical feel of the keyboard from its electrical functions to allow greater customized key feedback. Modern keyboards rely on electromechanical actuators to transmit key signals to a central processing unit. The components under a single keycap often incorporate multiple structures, such as a key travel mechanism (butterfly or dome switch), a tactile feedback structure (membrane), and electrical contacts or electrodes.

　　

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Schematic principle

Due to the tight space constraints of modern keyboards, particularly laptop keyboards, haptic feedback components are often nested within the key travel mechanism below the electrical traces. The part sandwich inhibits independent component modification because the manufacturer must redesign the entire system to achieve a different keyboard experience. Also, when it comes to haptic feedback, different users have different tastes, with some preferring silent, low-key experiences, while others prefer loud keystrokes and long keystrokes.

In order to better meet individual user preferences, Apple has proposed a method for decoupling the mechanical and tactile functions of the keys from their electrical functions. Specifically, it replaces the electrical contacts and traces with a non-contact distance sensor, while the travel mechanism and feedback structure remain substantially intact. The key design of this patent is the light emitter aimed at the bottom reflective surface of the keycap. An accompanying photodetector or a central detector connected to the light guide generates an electrical signal in response to the received optical signal. When processed by the keyboard controller, the signal can be used to estimate parameters such as the force, speed and distance generated by the user pressing the keys.

The result is that the data set obtained is much wider than the simple "open or close" circuit constraint parameters seen on traditional keyboards. The Apple invention can support force sensitive input applications by applying a predetermined threshold to the input signal. Other embodiments include dynamic threshold adjustment on a per-key and per-application basis, allowing the user to set one input level for word processing and another for gaming. It is unclear whether Apple intends to implement its customizable keyboard in future Mac products.