An Engineers' AR Display
It was not that long ago, that an augmented reality display weighed 8-10 ounces, and fitted over a pair of spectacles, rather than be the spectacles themselves. It was also not that long ago, that eye tracking hardware had to be pressed to the eyelid to detect muscle twitches.
A new concept on eye tracking, does two things. Firstly, it integrates both concepts into one device, by registering eye movement through the simple expedient of tracking pupil movement via machine vision, and mounting the tracking camera on the rear frame of the device.
Secondly, the AR display itself, is relegated to the size and weight of a pair of glasses, with the display text appearing as an overlay on the glasses themselves.
At least that is the intent of a group of scientists at he Fraunhofer Institute for Photonic Microsystems IPMS in Dresden, Germany. So far, they have the eye tracking down pat thanks to a CMOS chip with an eye tracker in the microdisplay of the glasses.
Without having to use any other devices to enter instructions, the wearer can display new content, scroll through the menu or shift picture elements.
The chip measuring 19.3 by 17 millimeters is fitted on the prototype eyeglasses behind the hinge on the temple. This gives the tiny cameras abutting the chip, the chance to see both eyes' positions visually - so long as the eyes are open of course. The display is projected, again by an embedded projection device, back into the retina of the eye as direct retinal projection. This is another reason why it is so valuable to know where the pupil is at any given moment.
The direct retinal projection attempts to give a display that seems to be at a distance of about one meter, and means that the spectacle frames can be fitted with any prescription lens the wearer requires - they are not integral to the display overlay.
OLEDs are used in the prototype, to try and overcome natural luminescence, so that the glasses can be used outdoors. However, the prototype is still a long way from commercial development.