Apple replaces mechanical keyboard switches with proximity sensors in new invention
An Apple invention detailed in a patent application published Thursday describes a method of decoupling a keyboard's mechanical feel from its electrical functionality using proximity sensors, which allows greater customize key feedback.

At its heart, Apple's patent application for "Depressible keys with decoupled electrical and mechanical functionality," published by the U.S. Patent and Trademark Office, details a computer keyboard that replaces common
Contemporary keyboards rely on electromechanical actuators to transmit key press signals to a central processing unit. The components usually incorporate multiple structures under a single keycap, for example a key travel mechanism (butterfly or dome switch), tactile feedback structure (membrane) and electrical contacts or electrodes.
Due to tight space constraints in modern keyboards, especially laptop versions, the tactile feedback component is often nested within the key travel mechanism below the electrical traces. The parts sandwich inhibits independent component modification, as a manufacturer must rework the entire system to achieve different keyboard experiences.
Users, meanwhile, have divergent tastes when it comes to a tactile feedback, as some prefer a silent, low travel key press, while others like loud "clackity clack" keys with long throws. Keyboard "feel" is hotly debated when Apple launches a new MacBook, for example.
To better cater to individual user preferences, Apple proposes a method for decoupling the mechanical and tactile functionality of a key from its electrical functionality. Specifically, the document replaces electrical contacts and traces with non-contact proximity sensors, while travel mechanism and feedback structures remain largely intact.
In most embodiments, Apple's key design features a light emitter aimed at the reflective bottom surface of a keycap. An accompanying light detector, or central detector connected to a light guide, generates an electrical signal in response to the received light. When processed by a keyboard controller, the signals can be used to estimate force, velocity and distance metrics to accurately determine when a key is pressed.
The resulting data set is much wider than simple "open or closed" circuit constraints seen on traditional keyboards. By applying pre-determined thresholds to incoming signals, Apple's invention can in some cases detect errant key presses and support force-sensitive input applications.
Other embodiments include dynamic threshold adjustments on a per-key and per-application basis, allowing users to set one input level for word processing and another for gaming.
As for tactile feedback, Apple's invention includes contingencies for installing structures formed from a materials capable of elastic deformation such as an electroactive polymer or shape-memory metal. In some embodiments, users can adjust the feel of these components on the fly.
Apple's document goes on to describe alternative embodiments and a detailed rundown of how the optical sensor mechanism functions. The company also mentions manufacturing benefits of deploying a decoupled keyboard system.
It is unclear whether Apple intends to implement its customizable keyboard in a future Mac product. The company is, however, expected to announce new Mac hardware at a special event next week.
Apple's patent application for a keyboard with decoupled electrical and mechanical functionality was first filed for in April 2015 and credits Chang Zhang, Dayu Qu, Ray L. Chang and John S. Camp as its inventors.

At its heart, Apple's patent application for "Depressible keys with decoupled electrical and mechanical functionality," published by the U.S. Patent and Trademark Office, details a computer keyboard that replaces common
Contemporary keyboards rely on electromechanical actuators to transmit key press signals to a central processing unit. The components usually incorporate multiple structures under a single keycap, for example a key travel mechanism (butterfly or dome switch), tactile feedback structure (membrane) and electrical contacts or electrodes.
Due to tight space constraints in modern keyboards, especially laptop versions, the tactile feedback component is often nested within the key travel mechanism below the electrical traces. The parts sandwich inhibits independent component modification, as a manufacturer must rework the entire system to achieve different keyboard experiences.
Users, meanwhile, have divergent tastes when it comes to a tactile feedback, as some prefer a silent, low travel key press, while others like loud "clackity clack" keys with long throws. Keyboard "feel" is hotly debated when Apple launches a new MacBook, for example.
To better cater to individual user preferences, Apple proposes a method for decoupling the mechanical and tactile functionality of a key from its electrical functionality. Specifically, the document replaces electrical contacts and traces with non-contact proximity sensors, while travel mechanism and feedback structures remain largely intact.
In most embodiments, Apple's key design features a light emitter aimed at the reflective bottom surface of a keycap. An accompanying light detector, or central detector connected to a light guide, generates an electrical signal in response to the received light. When processed by a keyboard controller, the signals can be used to estimate force, velocity and distance metrics to accurately determine when a key is pressed.
The resulting data set is much wider than simple "open or closed" circuit constraints seen on traditional keyboards. By applying pre-determined thresholds to incoming signals, Apple's invention can in some cases detect errant key presses and support force-sensitive input applications.
Other embodiments include dynamic threshold adjustments on a per-key and per-application basis, allowing users to set one input level for word processing and another for gaming.
As for tactile feedback, Apple's invention includes contingencies for installing structures formed from a materials capable of elastic deformation such as an electroactive polymer or shape-memory metal. In some embodiments, users can adjust the feel of these components on the fly.
Apple's document goes on to describe alternative embodiments and a detailed rundown of how the optical sensor mechanism functions. The company also mentions manufacturing benefits of deploying a decoupled keyboard system.
It is unclear whether Apple intends to implement its customizable keyboard in a future Mac product. The company is, however, expected to announce new Mac hardware at a special event next week.
Apple's patent application for a keyboard with decoupled electrical and mechanical functionality was first filed for in April 2015 and credits Chang Zhang, Dayu Qu, Ray L. Chang and John S. Camp as its inventors.
Comments
All said , there is still room for improvement in the new keyboard. It will not be long before the LED Keyboard is completely customizable. Or at least you will be able to see the other keys available when you press a function key. I still look for the special characters and would love to see them on the actual keyboard.
Reduced travel can affect accuracy, if the user can't tell whether they hit the key hard enough to register, or they strike the key too hard, and accidentally hit adjacent keys as a result. Even if the spacing has more of an effect, users may be distracted by the different feel of the keys, and blame that for the errors, which will lead to a distrust of a shallow travel keyboard.
Still, Apple have been training us to get used to less travel in the keyboard, with the switch to the "Chiclet" keyboard, the "glass" keyboard on the iPhone and iPad, and the butterfly switches on the MacBook. Eventually I expect keys will have no actual travel, but will fool us with haptic feedback, the same way the trackpad and the new home button do. The real trick is fooling us into thinking there are physical keys there to better enable touch typing.
Couple this analog travel with variable tactile feedback, and now each key has multiple user-detectable levels of actuation or function. Push too lightly, and you get nothing. Push really hard and you get a second function (like a capital letter or an alt-keystroke). One could feel each click more and more as they pushed down more.
Since it's analog, it can be made user configurable. Don't like how little force it takes to get a mis-typed key? Adjust it in system preferences to be less sensitive. Want the lightest touch to work so you can type silently? Make it less sensitive? Tired of accidentally hitting the space bar? Notch it up so when you gotta really push it.
I would expect this this on a keyboard for an iMac or Mac Pro instead of a MacBook. Since it probably would make a standard keyboard thicker (at least until Apple could refine the tech).
Or am I completely misunderstanding this patent?
I'd like to see Apple add tactile feedback to iPads using 3D Touch, but this isn't that patent.