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. 2020 Sep 9;10(1):14804.
doi: 10.1038/s41598-020-71233-1.

A laser emitting contact lens for eye tracking

A Khaldi  1 , E Daniel  2 , L Massin  2   3   4 , C Kärnfelt  5   4 , F Ferranti  5   4 , C Lahuec  3   4 , F Seguin  3   4 , V Nourrit  2 , J-L de Bougrenet de la Tocnaye  2
Affiliations

A laser emitting contact lens for eye tracking

A Khaldi et al. Sci Rep. .

Abstract

In this paper, we present the first realisation and experimentation of a new eye tracking system using an infrared (iR) laser pointer embedded into a wireless smart contact lens. We denote this contact lens prototype as the cyclops lens, in reference to the famous hero of the X-Men comics. The full eye tracker device combines the smart contact lens and its eyewear, which provides a primary source of energy and the beam detection system. We detail the assembling and encapsulation process of the main functionalities into the contact lens and present how a gaze tracking system is achieved, compared to existing conventional eye-tracking ones. Finally, we discuss future technical improvements.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Gaze direction detection system. Each eye wears a scleral lens where a VCSEL is embedded. The VCSEL beams (solid line) are reflected by a beam splitter towards an IR camera placed above the eyes. The spot locations on the beam splitter are represented by disks and the direction of gaze by dashed lines.
Figure 2
Figure 2
Successive steps from device to worn contact lens; (a) dimension and content of the contact lens, (b) sealed electronics: from left to the right, electronic circuit and components, encapsulated in the contact lens, Cyclops worn on a human eye. (c) top view of the cyclops lens with secondary antenna connected to electronics (insert : oblique view of the VCSEL).
Figure 3
Figure 3
Transmitted RF Energy from the primary antenna to the NXP output (a) electronic primary antenna in the eyewear, a wire in the left corner connects it to a generator, (b) image of the directional flashing VCSEL of the smart lens. (c) Power harvesting capability of the NXP chip, with the output supply voltage (filled diamond) and the output power (filled square) as a function of the load current.
Figure 4
Figure 4
Eye tracking demonstrator (a) schematic of the overall system depicting the artificial eye (A) on which the cyclops lens is mounted, the servo-motor (F) and associated micro-controller (E) to control the eye direction, the eyewear (D) with the primary antenna, the beam splitter (B) reflecting the VCSEL beam (represented by a solid red line) towards the IR camera (C) (mounted on top of the eyewear). (b) A photo of the prototype.
Figure 5
Figure 5
Results of the eye-tracker (a) Upper image representing successively the VCSEL spot recorded on the IR camera for 5 different orientations (− 20°, − 10°, 0°, 10°, 20°). Please note that it is a concatenated image of the spot in different positions (See Video S1). (b) The graph shows the VCSEL spot coordinates for the 5 previous positions.
Figure 6
Figure 6
The Cyclops prototype in the foreground, with the camera mounted on the eyewear and connected to a PC in the background (we can notice the white spot). See Video S1.
See this image and copyright information in PMC

References

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