Multipurpose Bio-Monitored Integrated Circuit in a Contact Lens Eye-Tracker

Abstract

We present the design, fabrication, and test of a multipurpose integrated circuit (Application Specific Integrated Circuit) in AMS 0.35 µm Complementary Metal Oxide Semiconductor technology. This circuit is embedded in a scleral contact lens, combined with photodiodes enabling the gaze direction detection when illuminated and wirelessly powered by an eyewear. The gaze direction is determined by means of a centroid computation from the measured photocurrents. The ASIC is used simultaneously to detect specific eye blinking sequences to validate target designations, for instance. Experimental measurements and validation are performed on a scleral contact lens prototype integrating four infrared photodiodes, mounted on a mock-up eyeball, and combined with an artificial eyelid. The eye-tracker has an accuracy of 0.2°, i.e., 2.5 times better than current mobile video-based eye-trackers, and is robust with respect to process variations, operating time, and supply voltage. Variations of the computed gaze direction transmitted to the eyewear, when the eyelid moves, are detected and can be interpreted as commands based on blink duration or using blinks alternation on both eyes.

Head-Mounted Miniature Motorized Camera and Laser Pointer Driven by Eye Movements

“…Another source of improvement consists of using a contact lens eye tracker, as we are developing in parallel [ 20 , 21 ], to simplify gaze detection and improve the headband functionality.…”

Restored vision—augmented vision: arguments for a cybernetic vision

“…IMT Atlantique is one of the pioneers in this emerging field. We have tested the encapsulation of several building bricks (flexible micro-batteries [32], data communication circuits [33] by near field communication (NFC) protocol, ASIC 2 and photodiodes for a centroid calculation [34]) as well as complete functions (double laser pointer [35], eye-tracker, blink detection [36]). We are also one of the few to perform biocompatibility tests (CE marking of our laser pointer).…”

“…IMT Atlantique est un des pionniers dans ce secteur en émergence. Nous avons testé l'encapsulation de plusieurs briques de base (micro-batteries flexibles [32], circuits de communication de données [33] par protocole de communication en champ proche (NFC en anglais), ASIC 2 et photodiodes pour un calcul de barycentre [34]) ainsi que des fonctions complètes (double pointeur laser [35], oculomètre, détection de clignement d'oeil [36]). Nous comptons également parmi les rares à effectuer des tests de biocompatibilité (marquage CE de notre pointeur laser).…”

Design of a Multimodal Oculometric Sensor Contact Lens

“…In this paper, we focus on three of them: gaze direction (GD), pupil dilation (PD) and accommodative power (AP). A blinking measurement can also be easily added [2]. Numerous works have shown that these oculometric features provide complementary information about the subject's cognitive load and attention, and yield great benefits when combined.…”