An Apple patent application published by the U.S. Patent and Trademark Office on Thursday details an advanced haptic feedback system that uses vibration and temperature control to simulate the feeling of wood, metal and other surfaces on a device display.


Aptly titled “Touch Surface for Simulating Materials,” Apple’s invention takes haptic feedback a step further than current systems seen on Apple Watch or even the MacBook line’s mind-bending Force Touch multitouch trackpad.

Based on the basic principals of haptic feedback, Apple’s proposed system applies an actuator capable of moving horizontally, vertically, or a combination of both to create a vibratory sensation on a user’s finger. Varying the amplitude of such vibrations over time and space can simulate rough or smooth surfaces. Rough surfaces and textures are simulated through stronger vibrations as compared to smooth surfaces.


The system also harnesses data from capacitive sensors, positioning sensors, force sensors and other sensing components to detect where a user’s finger is placed on screen. Tying it all together with computer display technology, Apple asserts that its haptic system can reproduce the feeling of different textures, surfaces and materials on a glass or plastic substrate.

In one embodiment, a user would be able to “feel” wood grain when they draw their finger over an image of a plank of wood. Vibrations can be adjusted based on finger pressure, reflective of increased force on a simulated material.

Perhaps most interesting is Apple’s mention of Peltier devices, otherwise known as thermoelectric cooler or heat pump. Operation of a TEC is based on the Peltier effect, which describes a heating or cooling effect resulting from an electric current flowing across the meeting point of two conductive materials. Arranged in alternating series expands the effect across a plane, drawing heat to one side while cooling the other.

Peltier devices can be found in certain consumer gadgets and scientific instruments, though computer buffs may recognize TECs as a technology used in overclocking applications.


As applied to Apple’s patent, embedded Peltier devices can enhance simulated touch by adding temperature fluctuations to the mix. Continuing with the example above, a screen’s temperature may be made warmer when displaying a piece of wood, or cooler when displaying a sheet of steel. Taking the idea even further, Apple points out that surface temperatures can change dynamically, warming simulated metal or plastic as heated by a user’s finger.

These TECs need not be distinct components, Apple says, and can instead be piezoelectric actuators that also produce heat or a combination of components stacked on top of each other.

Apple is showing greater interest in haptic feedback systems, as seen in Apple Watch and trackpads incorporated into the latest MacBook models. Called Force Touch, the MacBook version is a completely self-contained system employs force sensors, a vibration motor and controller (Taptic Engine) to respond to user clicks, presses and other gestures with haptic feedback. Unlike the hinge-based multitouch trackpad it replaces, Apple’s Force Touch unit doesn’t move, but the tech is so convincing that many people can’t tell the difference.


Apple’s surface simulation patent application was first filed for in October 2013 and credits Paul G. Puskarich as its inventor. Interestingly, Puskarich is also named as a principle inventor on another Apple patent detailing a haptic feedback concept identical to MacBook’s Force Touch trackpad. The IP was uncovered by AppleInsider three years ago.
from AppleInsider – Apple News and Rumors Since 1997