An Apple patent application published Thursday, September 21 confirms the company's continued interest in advanced force detection technology, dubbed 3D Touch in Apple parlance, with a novel back-sensing configuration that could lead to thinner handset designs, AppleInsider says.
Published by the U.S. Patent and Trademark Office, Apple's application for "Detecting backside force in a touch-screen device" details a method of integrating and calibrating force sensors to detect back-side user input.
In concert with detecting back-side force input, the integrated sensor would be tasked with measuring potential strains during normal use that could lead to inaccurate front-side readings. Such a configuration would allow the implementation of exceedingly thin chassis designs prone to flexing during force press operations.
Current state-of-the-art technology, like 3D Touch, integrates a force sensing layer on, near or beneath a smartphone's display or cover glass. Apple's current solution detects force by measuring and mapping minute changes in capacitance between an iPhone's cover glass and a rigid metal sensor layer embedded in the backlight.
A separate multitouch capacitive sensor disposed above the display pulls double duty in 3D Touch by determining finger location during force gestures. Completing the system's major operating components is a haptic feedback module dubbed the Taptic Engine.
In current iOS versions, 3D Touch powers a handful of force sensitive controls including Peek and Pop, a user interface feature that provides linearly proportional software responses to increased finger pressure. Lightly pressing an interactive onscreen object like a hyperlink opens a new temporary Safari window, for example, allowing users to "peek" into its content. A harder press "pops" that floating UI pane into fullscreen view.