The rear touchpad panel helps the user to d more with their devices and also none of the mobile phone with such features has been seen to date.Sony has implemented the similar feature earlier on PS-Vita which allows extra functionality and controls for various games.
As of now, there are no details whether this feature will be made available upcoming Pixel devices or not, but if it did then will be the first smartphone to come with such an extra features.Google already has similar kind of Gesture support on Pixel and Pixel XL fingerprint scanner.These gestures are very limited only to swipe up or down the notification panel or hide the notification panel.
As per fig no.3, the Google is planning to bring full rear-facing touchpad that surrounds the rear-facing fingerprint scanner.This larger rear-facing touchpad will allow the user to draw some gestures to launch apps or shortcuts.As per image, the recessed area is not been shown as a fingerprint sensor, but it looks similar to one found on Pixel and Pixel XL.There is the camera placed at the centre with speaker right side of it above the recessed area.There are the lot of uses of the rear-facing touchpad like zooming the images, scrolling the web pages, managing music etc.
We have to wait for the final product renders for the same if Google plans to launch such a device.
