Patent ID: 12235441

DETAILED DESCRIPTION

For the sake of clarity, the same elements are denoted by the same reference numerals in the various figures.

FIG.1shows a contact lens1worn by a person's eye (O) near the rim of a frame.

The contact lens1, preferably a hard or hybrid scleral lens, bears, via encapsulation in its membrane10, two light sources11,12.

These sources may be light-emitting diodes (LEDs) or vertical-cavity surface-emitting lasers (VCSELs), or edge-emitting laser diodes. The light emitted in the infrared by these sources11,12may be coherent (VCSEL) or weakly coherent (LED).

When the contact lens1is worn by the person's eye (O), each light source11,12may emit a light cone or beam F1, F2intended or otherwise to illuminate a region of a position-sensitive detector, as described in detail below.

A shape of the sources11,12, such as for example diodes of elliptical shape or the installation of a shaping optic on each of the sources, may be envisaged so that each light beam is in the shape of a narrow optical beam in the detection region as described below.

As shown inFIG.2in relation to an orange LED12, the contact lens1incorporates, within its membrane10, a rechargeable autonomous battery which supplies the LED12with power.

This battery is advantageously a deformable accumulator as described and claimed in patent application WO 2018/167393 A1.

The light beams emitted by the sources11,12may be detected by the contact lens1by itself, which makes it possible to detect the direction of the gaze in space.

Alternatively, in the case where detection of the beams is useful, it is possible to implement an external detection device comprising one or more position-sensitive detectors (PSDs) sensitive to the position of the beams, which allows the extraction of the angle of inclination of the eye with respect to these spectacles or this headset and therefore with respect to the normal of the gaze.

FIGS.3A and3Bshow configurations where two PSD detectors2.1,2.2are arranged on either side of a transparent region T facing the iris of the eye. In the case ofFIG.3A, the beam F1from the source11illuminates the transparent region while the beam F2from the source12illuminates the sensitive detection region2.2. In the case ofFIG.3B, the beam F1from the source11illuminates the sensitive detection region2.1, while the beam F2from the source12illuminates the transparent region T.

The one or more PSD detectors2,2.1,2.2may be integrated into the support of a spectacle frame or an augmented reality headset.

The configurations ofFIGS.3A,3Bshow the integration of two detectors2.1,2.2into a support, such as an augmented reality headset, requiring a transparent region T facing the direction of the gaze.

For charging the flexible battery13integrated into the contact lens, a magnetic induction charging system is advantageously provided. Thus, preferably, an antenna in the form of an induction coil14, with a rectifier connected thereto, are encapsulated in a contact lens1.

One advantageous exemplary charging system is shown inFIG.4: an induction antenna30is integrated into a spectacle frame3, which preferably bears the PSD detectors. The antenna30transfers energy through magnetic coupling to the antenna14of the contact lens1which may be in place on a person's eye (O) during charging by magnetic induction. Reference may be made to publication [6] for further details.

For the actual detection, two configurations are possible.

According to a first configuration (FIG.5), two PSD detectors2.1,2.2are placed in front of the eye. One favored arrangement makes provision for the detector2.1to be in a lower location with respect to the contact lens1, while the other detector2.2, substantially at 90° to the detector2.1, is as close as possible to the nasal wall so as not to obstruct the vision. The beams from the two sources11,12are directed respectively toward the detectors2.1,2.2.

If the eye rotates, each beam still intercepts the PSDs since the position P1/P2given by the detectors2.1,2.2does not change with a rotation θ/β.

In a second configuration (FIG.6), a single PSD detector2is placed in front of the eye.

The position of each beam from the two sources11,12on the detector2makes it possible to deduce the direction of the person's gaze. Since the sources11,12are not oriented perpendicular to the PSD detector2, there is a region in the center thereof, shown in dotted lines inFIG.6, which will not be illuminated and which could be entirely empty.

The operation of a PSD detector2is shown inFIG.7: each of the positions P1, P2of the beams emitted by the two sources11,12is translated into photocurrents which may easily be measured, as explained in publication [3].

FIGS.8A and8Billustrate certain steps in a process for producing a contact lens according to the invention, of scleral type.

The membrane10consists here of two films15,16made of transparent polymer, for example a hydrogel.

Each of the two films15,16is first of all shaped as usual.

Next, all of the electronics, with the possible exception of the antenna for collecting energy by induction, are placed on the inner face of the outer film15.

Thus, the electronics, including the light sources11,12, are perfectly positioned within the film16.

Once this positioning has been carried out, the two films15,16made of transparent polymer are sealed together, using UV glue for example.

Thus, all of the electronic or optoelectronic components are perfectly positioned and encapsulated between the two films15,16.

Of course, the invention is not limited to the exemplary implementations that have just been described.

Other variants and improvements may be envisaged without departing from the scope of the invention.

For example, the device for detecting the beams from the sources emitted from the contact lens may be integrated into any type of fixed support and preferably into a frame, for example an augmented reality headset or into a head-up (HUD) display screen.

Other variants and improvements may be made without departing from the scope of the invention.

The invention is not limited to the examples that have just been described; in particular, features of the illustrated examples may be combined with one another within variants which are not illustrated.

LIST OF CITED DOCUMENTS

1: N. M. Farandos et al., “Contact lens sensors in ocular diagnostics”, Advanced Healthcare Materials, vol. 4, no. 6, 4, pp. 792-810, April 2015.2: Z. Blum, D. Pankratov & S. Shleev (2014). “Powering electronic contact lenses: current achievements, challenges, and perspectives”. Expert Review of Ophthalmology 9(4).3: S. Cui, Y. C. Soh, “Linearity indices and linearity improvement of2-D tetra-lateral position sensitive detector”. IEEE Transactions on Electron Devices, Vol. 57, pp. 2310-2316, 2010.4: G. Buchberger et al., “Transparent, flexible, thin sensor surfaces for passive light-point localization based on two functional polymers”, Sensors and Actuators A: Physical, A239, pp. 70-78, 2016.5: Electro-optics, December 2018, January 2019, pp. 11.6: Y. -J. Kim et al., “Eyeglasses-powered, contact lens-like platform with high power transfer efficiency,”Biomedical Microdevices, vol. 17, no. 4, July 2015.