Apple Reveals New Multitouch with "Frustrated Total Internal Reflection" (FTIR) and Capacitive Sensing

Apple states that their invention relates to detecting force and touch using what is called "frustrated total internal reflection" (FTIR) and capacitive location. FTIR is a name used by the multi-touch community to describe the multi-touch methodology developed by Jeff Han (Han 2005).

According to Apple, FTIR determines applied force by the user's finger within infrared transmit lines on a touch device. A pattern of such lines determine optical coupling with the touch device. Capacitive sensing can determine (A) where the finger actually touches, so the touch device more accurately infers applied force; (B) whether finger touches shadow each other; (C) as a baseline for applied force; or (D) whether attenuated reflection is due to a current optical coupling, or is due to an earlier optical coupling, such as a smudge on the cover glass. If there is attenuated reflection without actual touching, the touch device can reset a baseline for applied force for the area in which smudges remain. Infrared transmitters and receivers are positioned where they are not visible to a user, such as below a frame or mask for the cover glass.

The technology is used in Microsoft's Surface technology called PixelSense. We briefly covered this technology in a 2011 report titled "Could Apple Challenge Microsoft's Next-Gen Surface Technology?"

Apple acknowledges that "Light can also be scattered by the touch, which might also provide a source of information about the touch. For example, a tabletop touch product called "Surface", marketed by Microsoft Corporation of Redmond, Wash., includes an FTIR tabletop, with cameras mounted behind it that detect light refracted by pressure." The video below brings this point to life.

Another source of information about this type of multitouch technology could be found here.

Multiple Reflection Detectors: Apple's patent FIG. 4A noted below shows us a conceptual drawing of a first pattern of infrared transmitters and receivers.

Apple notes that the new multitouch technology could apply to a wide range of devices such as an iPhone, iPad, iPod, iMac, MacBook Pro/Air, peripheral devices and beyond.

This new Multitouch Technology may provide users with a Superior Gaming Experience

Apple states that this new multitouch technology would make it advantageous for the user to be able to indicate an amount of force applied when manipulating, moving, pointing to, touching, or otherwise interacting with, a touch device.

For example, it might be advantageous for the user to be able to provide input with an analog control in response to an amount of force, such as a gas pedal on a simulated car, or a control surface of an airplane in a flight simulator. For a fourth example, it might be advantageous for the user to be able to provide input, such as simulated body movements or otherwise, in a virtual reality (VR) simulation (possibly with haptic feedback), or in an augmented reality program.

Apple's patent also gives me the impression that this new multitouch technology could also be used for a future version of Touch ID for multi-finger fingerprint Authentication?

Apple's patent application is steep in technical and for those wishing to explore it, check out patent application 20140092052 which was originally filed in Q3 2012. Apple credits Martin Grunthaner, Peter Richards, Romain Teli and Steven Hotelling.

There were a number of display related patent applications published today by the US Patent and Trademark Office. Here are few that you check out:

Display with Liquid Crystal Shutters for Minimizing Display Borders

Borderless Display with Light-Bending Structures

Electronic Devices With Displays Having Optical Films

Display with Electromechanical Mirrors for Minimizing Display Borders

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