Force Touch

Force Touch is a technology developed by Apple Inc. that enables trackpads and touchscreens to distinguish between different levels of force being applied to their surfaces. First unveiled on September 9, 2014, during the Apple Watch introduction, Force Touch is a pressure-sensitive multi-touch technology.^[1] The technology is designed to add another method of input to Apple’s devices. Beginning with the Apple Watch, Force Touch has been introduced to many of the products within Apple’s lineup, including the MacBook with Retina display, MacBook Pro, Magic Trackpad 2, and flagship iPhone models, namely the iPhone 6S, iPhone 6S Plus, iPhone 7, iPhone 7 Plus, iPhone 8, iPhone 8 Plus, iPhone X, iPhone XS, and iPhone XS Max, where the technology is branded as 3D Touch. App developers can also make use of the features.^[2]

The technology on iPhones has 3 different levels of input, which enables users to customise a preference of light, medium or firm press onto the iPhone to access the other information^[3]

Hardware

Force Touch is operated with many components. On the Apple Watch, a series of electrodes line the curvature of the screen. When a press is detected, these electrodes determine the pressure applied. A similar process occurs in trackpad applications of the technology (such as in the MacBook Pro and Magic Trackpad 2), although sensory information is determined by a series of four sensors that align with the corners of the trackpad. The feedback is then relayed to the "Taptic Engine", an electromagnetic linear actuator. Unlike typical motors, the linear actuator does not rotate but oscillates back and forth. The Taptic Engine produces immediate feedback without the need to offset the balance of mass. The feedback provided is called haptic feedback, a very sensible vibration that relays information back to the user with precision.^[4]

Functions

Extending past the multi-touch abilities of a touchscreen, Force Touch has a number of operations in Apple's software and hardware. Information such as reminders and dates can be pressed down with force to expand them so users can perform more actions more quickly, and applications developed for Apple's software can take advantage of Force Touch by implementing their own functions where Force Touch can be used. On the MacBook with Retina Display and the 2015 MacBook Pro, users can increase the rate of fast forward of videos simply by exerting a larger pressure on the Force Touch trackpad. On iPhones, the technology has been used extensively as a shortcut to previewing images, videos and finding shortcuts and previously not available features on the home screen of the phone

Products

Force Touch is currently embedded into the screen of the Apple Watch and the trackpads of the MacBook Pro Retina, MacBook (Retina), and the Magic Trackpad 2.

A more sensitive version of Force Touch named 3D Touch is included in iPhone 6S and later models. 3D Touch works using capacitive sensors integrated directly into the display. When a press is detected, these capacitive sensors measure microscopic changes in the distance between the backlight and the cover glass. This information is then combined with accelerometer signals and touch sensors to provide an accurate interpretation of the user's intentions. The linear actuator within the Taptic Engine is capable of reaching peak output in just one cycle and producing vibrations that last 10 milliseconds. When the user presses or holds the iPhone screen, it will trigger pressure-sensitive capability that will open up menus and actions, as seen on Apple Watch. The user can press down or hold the screen and pull up or open up context-sensitive menus, switch or close apps or can also see photo effects like Live Photos.^[5] The 3D Touch technology allows the device to recognize the pressure of a user's touch inputs, thus distinguishing between normal and more forceful touches.^[6] The iPhone XR, released in 2018, does not include 3D Touch. ^[7]

Litigation

Apple Inc. was subject to a lawsuit by Immersion Corporation due to allegations of infringement of various patents owned by Immersion on the 3D Touch technology Apple developed.^[8] According to the complaint, the asserted patents generally relate to apparatus for, and methods of, implementing pressure-enabled haptics to enhance the user experience on electronic devices. In particular, the ‘507 patent generally relates to systems and methods in which the mobile electronic device determines a pressure and a change in pressure based on contact data. The ‘488 patent relates to systems and methods for generating an actuator signal to output a haptic effect based on the user’s interaction with a graphical object on a touchscreen. The ‘260 patent generally relates to systems in which the electronic device detects different levels of pressure on the device and providing a tactile sensation in response. Lastly, the ‘710 patent generally relates to systems and methods for generating an actuator signal to output a haptic effect indicating whether the user’s input is recognized or unrecognized and that a corresponding command was (or was not) found.^[9] As of October 2017, neither party nor the court had disclosed any conclusion so the litigation is assumed to be ongoing.

References

Further reading

• http://www.computerworld.com/article/2956314/apple-ios/apple-s-force-touch-the-future-of-mobile-interfaces.html
• https://www.wired.com/2015/09/what-is-the-difference-between-apple-iphone-3d-touch-and-force-touch/
• http://www.imore.com/science-behind-taptics-and-force-touch