FR3001378A1 - Sensor for incorporation of intraocular pressure in flexible contact lens to diagnose glaucoma in patient, has inductor provided in star geometry and including series of branches and valleys, where end of each branch and valley is rounded - Google Patents

Abstract

The sensor (100) has an inductor (101) provided in a star geometry and including a series of branches (104a-104f) and valleys (105a-105f), where an end of each branch and each valley is rounded. The inductor includes even number of branches, where a distance between the center (110) of the star geometry and the end of each branch is less than or equal to the radius of a contact lens, preferably between 60 and 85 percent of the radius of the contact lens. The inductor includes two terminals (106a, 106b) arranged outside the inductor. An independent claim is also included for a flexible contact lens.

Description

The invention relates to the field of passive sensors, in particular intended to measure a physiological parameter such as intraocular pressure. The invention relates in particular to a flexible passive sensor for a contact lens.

Intraocular pressure is one of the physiological parameters for diagnosing certain diseases such as glaucoma. Ambulatory and non-invasive sensors have been developed to measure changes in intraocular pressure in a patient during his daily course. The development of non-invasive sensors allows more and more frequently on the one hand to overcome the invasive methods involving surgical procedures on the patient's eye. On the other hand, the fact of associating these sensors with ambulatory systems also avoids immobilization of the patient and allows an uninterrupted effective follow-up of the evolution of the intraocular pressure or of any other physiological parameter in real life situations. of the patient.

A passive sensor, that is to say not requiring any significant source of energy to operate, realized by means of an electric circuit LC, integrated in a soft contact lens and intended for the monitoring of the Intraocular pressure is known from EP 2 412 305 A1. A variation of the intraocular pressure causes a change in the resonance frequency of the LC circuit which can be detected and thus related to this variation. In particular, the application EP 2 412 305 A1 discloses a sensor comprising a capacitor and an inductance composed of first turns arranged on a first main face of a carrier substrate and second turns arranged on a second main face of the carrier substrate, opposite to the first main face. The document EP 2 412 305 A1 also discloses that the carrier substrate can be removed at least partially from the non-turn and / or capacitor regions, that the two sets of turns can intersect and be interconnected by conductive vias, as well as the capacitor can be formed integrally with the inductor so that its two electrodes are each arranged on one of the two opposite faces of the carrier substrate.

Some practical problems and unexpected constraints appeared during the manufacture of sensors and lenses as disclosed in EP 2 412 305 A1, in particular during the molding and then the use of the lenses.

A disadvantage observed in known state of the art sensors during the bending of the turns of the inductor at the time of molding the sensor in the lens, is the appearance of unwanted folds or wavelets at the edge of the lens of the lens. contact. These folds or wavelets result on the one hand in a strong discomfort for the subject carrying the lens, comparable to the introduction of dust between the eye and the lens, and on the other hand in a significant decrease in the sensitivity of the sensor . In addition, the appearance of folds and wavelets at the edges of a lens due to poor bending of the sensor during molding with the lens deforms the lens and the sensor in these areas, thus undesirably reducing the efficiency of the lens. physiological parameter monitoring. In addition, in circuits known in the state of the art whose inductance is of simple spiral geometry, it has been found that the electric field lines exceed the physical limits of the lens and extend to the outside thereof, so that they can be short-circuited by the ocular fluids, resulting in attenuation of the resonance phenomenon of the LC circuit performing the passive sensor. Out, a constraint is precisely that the LC circuit constituting the passive sensor must have a significant sensitivity to the edge of the lens, since intraocular pressure variations there will be sufficiently felt because of the greater curvature of the sensor in these regions by relative to the area corresponding to the center of the lens, where the curvature of the sensor, and therefore its sensitivity to changes in intraocular pressure, may be less important. The present invention therefore aims to solve or prevent the disadvantages described above noted during the manufacture of passive sensors, their subsequent molding in contact lenses, and when wearing lenses equipped with such sensors by a subject of which a physiological parameter such as the intraocular pressure must be followed. An object of the present invention is achieved by an intraocular pressure sensor for incorporation into a contact lens according to one aspect of the present invention, the sensor comprising an inductor and being characterized in that the inductor has a substantially star-shaped geometry comprising a succession of branches and valleys (or gorges). A star geometry adapted to the manufacture of passive sensor inductors for incorporation into a contact lens according to the invention can be described for example by mathematical equations, in particular by an algorithm of the following type using the following variables: variables: nspires number of turns of the spiral r, nt inner radius' turn turnwidth not pitch turn pitch angle of rotation in radians depth of turn variation (e = 0 for circular geometry) nbranch number of branches of the star Equations describing the spiral geometry: b = no / (2 7t); k = 1; I = 1; // Calculation of points in clockwise direction FOR angle-I = 0: pasanoe: (hspires * 2 ic) R = r, nt + (b * angle1 + e * cos (nbtancn * angle1)); spireX1 (k) = R * cos (angle1); spireY1 (k) = R * sin (angle1); k = k + 1; END // Calculation of the anti-clockwise rotation points to obtain the thickness of the turn FOR angle2 = (nspires * 2 10 (PaSangie * (-1)) (PaSangie * (-1)) R = rint + (b * angle2 + e * cos (nbranch * angle2)) + 'spire * (1 + (1/2) * sin (n / 4) * abs (sin (angle2 * hbranch))); spireX2 (I) = R * cos (angle2), spireY2 (I) = R * sin (angle2), I = I + 1, FIN Thus, a passive sensor according to the invention comprises an inductance whose geometry is essentially star-shaped with several branches, each branch being separated from the next by a valley or groove.In comparison, it has been observed that inductors with elliptical or oval geometry produce sensors which are less suitable for the measurement of intraocular pressure because the region presenting the more interest in monitoring this physiological parameter corresponds to the zone near the edge of the lens, which is not sufficiently covered by these geometries. In elliptical or oval omeletia, the existence of preferential directions implies that the measurement of the physiological parameter depends on the orientation of the lens. It has further been observed that the elliptical shape also tends to bend the lens further. A sensor using an inductance with essentially stellar geometry makes it possible to extend the branches of the star shape towards the zones of the edge of the lens, which makes it possible to extend the monitoring of the physiological parameter to these zones of the lens and therefore of the eye of the carrier subject. A passive sensor whose inductance adopts an essentially planar and star-shaped geometry also allows advantageous bending during molding for incorporation into a contact lens and makes it possible to overcome the unwanted folds observed on the edges of the lenses. equipped with sensors known from the state of the art. In addition, an inductance arranged essentially on the same first plane of the sensor instead of having turns on two parallel planes, as is the case for some known sensors of the state of the art, allows a better flexibility of the sensor . The invention has numerous variants and advantageous and non-limiting options detailed in the following.

Preferably, the end of each branch and each valley may be rounded. A starry geometry whose end of the branches and the bottom of the valleys are rounded is advantageous for a sensor intended to be incorporated in a flexible lens because the angular geometries presenting a risk of rupture during the molding of the lens are avoided. Advantageously, the inductor may comprise an even number of branches, preferably 6, 8 or 10 branches. It is also possible to produce a sensor with a star-shaped inductance with an odd number of branches. Nevertheless, the symmetry obtained with an even number of branches is preferred because it allows more flexibility and therefore a more advantageous folding of the sensor during molding with the lens. The number of branches, and therefore valleys, of the inductor can vary, but from 6 to 10 branches are preferred and advantageously cover, after molding, a plurality of zones at the edge of the lens. Advantageously, the distance between the center of the star-shaped geometry and the end of each branch may be substantially less than or equal to the radius of the lens, and may preferably be between 60 (3/0 and 85 (3/0 of the radius Similarly, the distance between the center of the star-shaped geometry and the bottom of each valley between two successive branches may be substantially less than or equal to the distance between the center of the star-shaped geometry and the end of the two branches. surrounding it, and may preferably be between 55 (3/0 and 75 (3/0 of the lens radius.) It is preferable and advantageous for the sensor to cover as much area as possible in the area corresponding to the border of the lens, while not obstructing or hardly the visibility of the subject brought to wear a lens provided with a sensor according to the invention, in particular in the dark or in conditions of weak lightning Such dimensions allow effective coverage of the eye area to be monitored and provide sufficient visibility for the wearer.

Preferably, the inductor may comprise a first terminal and a second terminal arranged on the outermost part of the inductor. Thus, the terminals or terminals of the inductor are arranged in an area of the sensor corresponding to an area of the eye for which the sensor is sufficiently sensitive to changes in intraocular pressure.

In an advantageous embodiment, the inductor may further comprise a first turn with a substantially star-shaped geometry starting from the first terminal on the outermost part of the inductance rotating in a first spiral direction towards the most the inside of the inductor, and a second turn with a substantially star-shaped geometry extending the first star-shaped turn in the same spiral orientation from the innermost portion of the inductor to the second terminal on the outermost portion. outside the inductor, the first starry coil and the second star-shaped coil being arranged essentially on a first plane of the sensor and intersecting in crossing zones. Thus the turns forming the inductor are substantially arcuate in shape according to the particular starry geometry of the inductor. In an inductance composed of turns intersecting according to this geometry and whose terminals start on the outermost circumference of the spiral, a significant potential drop is observed in the region on the edge of the sensor, which allows on the one hand to optimize the sensitivity of the sensor in this desired region, ie at the edge of the sensor and therefore once in place on the eye of a carrier subject, in a region of the eye for which the lens will be sufficiently subjected to intraocular pressure variations to allow effective detection of variations in the physiological parameter. On the other hand, this geometry advantageously makes it possible to confine the electric field lines in the zone occupied by the lens, thus avoiding short circuits by the ocular fluids. In addition, an inductance arranged essentially on the same first plane of the sensor instead of having turns on two parallel planes, as is the case for some known sensors of the state of the art, allows a better flexibility of the sensor .

According to a variant, the first turn and / or the second turn of the inductance is / are formed at least partially from a succession of segments with at least partially stellar geometry connected by conductive vias. In the variant for which the turns of the inductor intercross, it is preferable that at least one of the turns is composed of a plurality of segments to facilitate the arrangement of the crossings.

The segments can be connected to each other by conductive vias. In a preferred embodiment, the conductive vias can then be interconnected by conductive traces arranged on a second plane of the sensor, different from the first plane of the sensor, preferably parallel to the first plane of the sensor, the conductive traces being preferably separated from the first turn and / or the second turn by a dielectric medium. Thus, even if the inductance strictly speaking is advantageously arranged on the same first plane of the sensor, it is possible to arrange the electrical connections of the inductor, or more generally the sensor, on another plane, parallel to the foreground. but different from this one. When the sensor is molded in a contact lens, the first and second planes of the sensor are then parallel to each other in the direction of the thickness of the lens and are tangent to the eye of the subject. The first turn and the second turn can intersect in at least two, preferably only two, crossing zones. In the variant using conductive vias and / or conductive traces at the intersections between the turns, it is important to minimize the places where the sensor, in particular the inductor, is more rigid because of the plane on which are arranged the electrical connections. Two crossing zones are then preferred. In this way the inductance remains essentially arranged on a single plane and the crossing areas where the inductance, and therefore the sensor, will be thicker, are confined to two areas of the sensor. Advantageously, the crossing zones may be in valleys, in particular symmetrically opposite valleys, of the inductance. The case where the crossing zones are in branches of the inductor is also possible. Both cases are advantageous compared to the known sensors of the state of the art because the crossing zones are arranged so that the sensor has the least areas too rigid during molding in a lens. In addition, in a sensor having a star-shaped inductor with an even number of branches, it is advantageous to arrange the crossings between the turns symmetrically so as not to generate an imbalance when bending the sensor for molding with a lens. . The conductive vias can then be arranged in said crossing zones, which makes it possible to confine the regions of the sensor in which the inductance has an excess thickness. Preferably, the sensor according to the invention may further comprise at least one capacitor. The sensor according to the invention can therefore produce an LC circuit whose resonant frequency can be adjusted by adapting the capacitive value of one or more capacitors. The capacitive value of the capacitor or capacitors may for example advantageously be chosen so as to place the resonant frequency of the sensor in a desired range of frequencies authorized for medical applications. The objective is also achieved by a contact lens, in particular a soft contact lens, comprising a sensor according to the aspect described above or one of its variants or a combination thereof, in which the sensor is molded. inside the lens. The starry geometry of the inductance makes it possible to follow a physiological parameter even in zones bordering the lens which will be particularly affected by the change of the physiological parameter. When molding with the lens, the inductor can be bent perpendicular to the first plane of the sensor, which is the plane on which the sensor has been made, following the curvature of the lens. The star geometry of the inductance allows the sensor to adopt the spherical cap geometry of the contact lens in an improved manner compared to the state of the art, in particular it makes it possible to avoid undesired wrinkles. border of the lens. Various aspects making it possible to better understand the present invention as well as the advantages described above will be detailed in the following, in particular with the aid of advantageous embodiments illustrated by means of the accompanying figures, in which: Figure la illustrates schematically a example of an embodiment of an inductance of a sensor according to the invention; Figure 1b schematically illustrates another example of an alternative embodiment of an inductor of a sensor according to the invention; Figure 2 illustrates a detail of the inductor shown in Figure 1b; Figure 3 schematically illustrates another example of an embodiment of an inductance of a sensor according to the invention; Figure 4 illustrates a detail of the inductor shown in Figure 3; and Figure 5 illustrates another detail of the inductor shown in Figure 3.

In the following, analogous reference signs are used to describe identical elements or playing the same role in the different embodiments. For example, an element designated by the reference sign 101 in a first embodiment will therefore be designated by 201 in a second embodiment. Figures 1a, 1b and 2 schematically represent variants of an inductor 101 of a sensor 100 for measuring a physiological parameter such as intraocular pressure according to alternative embodiments illustrating aspects of the present invention. . Figures 1a and 1b show two different variants of a flat inductor 101, i.e., as it would appear in a sensor 100 before molding with a contact lens, in a view from above, and FIG. a detail of the inductor 101 of the variant of the embodiment illustrated in Figure 1b in a three-dimensional view. According to one aspect of the invention illustrated in Figures la and 1b, inductance 101 is arranged substantially on the same first plane of the sensor 100, facilitating its subsequent molding in a contact lens. The views of FIGS. 1a and 1b illustrate that the inductance 101 of a sensor 100 according to the invention has a substantially star-shaped geometry, comprising a succession of branches 104a, 104b, 104c, 104d, 104e, 104f and valleys 105a, 105b , 105c, 105d, 105e, 105f arranged around the center 110 of said starry geometry. In the two variants illustrated in FIGS. 1a and 1b, the ends of the branches 104a, 104b, 104c, 104d, 104e, 104f and the valleys 105a, 105b, 105c, 105d, 105e, 105f are rounded, which facilitates the bending of inductance 101 or more generally sensor 100 during subsequent molding in a lens with respect to a pointed star shape, but also with respect to a circular spiral inductor such as those known in the state of the art. In each case, the inductor 101 comprises an even number of branches, which has the advantage of facilitating its subsequent bending. In other embodiments, however, inductance 101 could comprise an odd number of branches. In the cases illustrated in Figures 1a and 1b, the inductor 101 comprises 6 branches, but it may comprise less or more, for example 4 branches and up to 8 or even 10 branches or more. Since the sensor 100 is intended to be molded into a contact lens and must therefore adopt a three-dimensional spherical cap geometry during molding, the described starry geometry of the inductor 101 has the advantage that unwanted folds are not desired. not observed at the edge of the lens when bending the sensor 100 for molding with the lens. A user wearing such a contact lens would therefore not suffer from the type of annoyance caused by folds at the edges of the lenses provided with sensors known in the state of the art. The dimensions of the sensor 100, and therefore variants of the inductor 101 illustrated in Figures la and 1b, must be such that they do not protrude from the lens after molding. The distance between the center 110 of the star geometry and the end of each branch 104a, 104b, 104c, 104d, 104e, 104f is therefore chosen to be substantially less than or equal to the radius of the lens. Preferably, this distance may be between about 60% and about 85% of the radius of the lens which will form the final product with the sensor 100. Similarly, the star geometry of the inductor 101 can be chosen such that the distance between the center 110 and the bottom of the valleys 105a, 105b, 105c, 105d, 105e, 105f is substantially less than or equal to the distance between the center 110 and the end of the two branches 104a, 104b, 104c, 104d, 104e, 104f respectively surrounding each valley 105a, 105b, 105c, 105d, 105e, 105f, Preferably the bottom of each valley 105a, 105b, 105c, 105d, 105e, 105f can therefore be located at a distance of a distance of about 55% (3/0 to about 75% of the radius of the lens constituting the final product with respect to the center of the star geometry 110. It should be understood that these values must also be such as to avoid disturbing the vision of a patient carrying a lens provided with such a sensor 100, in particular in the dark or in low light conditions. It is therefore preferable that the inductor 101, in particular the bottom of the valleys 105a, 105b, 105c, 105d, 105e, 105f do not overlap at least the area of a lens in which the sensor 100 will be molded, which corresponds to the mean area covering the pupil of a patient carrying the lens. According to a variant of an aspect of the invention, the inductor 101 illustrated in FIG. La comprises a turn 102 describing the star-shaped geometry, which begins with a first terminal 106a on its outer periphery and ends at the end. spiral by a second terminal 106b located on an inner periphery. The inductor 101 of the embodiment of a sensor 100 according to the invention illustrated in FIG. 1a is thus produced on a single plane of the sensor 100, which, in combination with its star-shaped geometry, gives it enough flexibility for molding in a contact lens producing neither folds nor wavelets on the edges of the contact lens. According to another variant of an aspect of the present invention, the inductor 101 of the embodiment illustrated in FIGS. 1b and 2 comprises two terminals 106a, 106b which are both located on an outer periphery of the inductor 101, unlike the variant illustrated in Figure 1a, where only one of the terminals is on the outer periphery.

To do this, the inductor 101 of the embodiment illustrated in FIGS. 1b and 2 comprises a first turn 102, starting at the first terminal 106a, and rotating in a spiral from the outermost part of the inductor 101 to the inside the inductor 101, then extending by a second turn 103, always rotating in the same spiral direction, but from the inner periphery to the second terminal 106b on the outer periphery of the inductor 101. This geometry allows a decrease of significant potential in the region bordering the sensor 100, which improves the sensitivity of the sensor 100 in this desired region of the eye of a patient when the sensor 100 is molded with a contact lens. Thus, the embodiment illustrated in FIGS. 1b and 2 is even more advantageous than that illustrated in FIG. 1a with respect to the sensors known from the state of the art since it not only provides a geometry more adapted to the bending of the sensor for incorporation into a contact lens, but also increased sensitivity in areas of the eye of interest for monitoring the physiological parameter. In addition, the electric field lines of the sensor 100 remain substantially confined in the molded lens, so that a short circuit by ocular fluids is avoided. Moreover, the two turns 102, 103 are arranged on the same first plane of the sensor 100. According to a variant of an aspect of the invention, the turns 102, 103 of the inductor 101 of the embodiment illustrated in FIGS. and 2 intersect in at least two crossing areas 109a, 109d.

In the case illustrated in FIG. 1b, the turns 102, 103 intersect only in the two crossing zones 109a and 109d, which advantageously allows the inductance 101 to remain arranged essentially on the same plane and to minimize the thicknesses in the sensor 100. In order to allow the turns 102, 103 of the inductor 101 to intersect, one of the turns 102 and 103, in the example illustrated in FIG. 1b, the turn 103, is composed of a succession of segments 103a, 103b connected by means of conductive vias 1071a, 1072a, 1071d, 1072d. In other embodiments, the turn 102 could be composed of such a succession of segments, or the two turns 102, 103 could be composed of such segments. The conductive vias 1071a, 1072a, 1071d, 1072d are therefore arranged in the crossing zones 109a, 109d, which in the case illustrated in FIG. 1b are the symmetrically opposed branches 104a, 104d of the inductor 101, but which, in d Other preferred advantageous embodiments could be valleys, preferably symmetrically opposed valleys of the inductor 101. FIG. 2 schematically illustrates a detail around the crossing zone 109d between the two turns 102, 103 of the inductor 101 of the embodiment illustrated in Figure 1b, this time in a three-dimensional view. According to a variant of an embodiment of the invention, the conductive vias 1071a, 1072a, 1071d, 1072d connecting the segments 103a, 103b of the second turn 103 are interconnected by means of conductive traces 1081a, 1081d arranged on a second plane of the sensor, parallel to the first plane of the sensor but different from the latter, and are therefore substantially parallel to the turns 102, 103. At the crossing zones 109a, 109d, the conductive traces 1081a, 1081d connecting the segments 103a, 103b of the second turn 103 by means of the conductive vias 1081a, 1081d are preferably separated from the first turn 102 and / or the second turn 103 by a dielectric medium. In this way the inductance 101 is arranged essentially on the first plane of the sensor, and the electrical connections are arranged essentially on the second plane of the sensor, which is essentially parallel to the foreground, as illustrated in FIG. illustrated in FIGS. 1b and 2, the advantages associated with the star geometry of the inductor 101 are combined with the fact that the terminals 106a, 106b of the two turns 102, 103 are situated on an outer periphery of the inductor 101, although that the turns 102, 103 both have a substantially star-shaped geometry along the branches 104a, 104b, 104c, 104d, 104e, 104f and the valleys 105a, 105b, 105c, 105d, 105e, 105f. The crossing zones 109a, 109d between the turns 102, 103 as well as the terminals 106a, 106b of the inductor 101 are located in branches 104a, 104d which are symmetrically opposite to the inductance 101, but in another embodiment, which may be also be combined with all the aspects described above, it is possible that the at least two crossing zones 109a, 109d and / or the terminals 106a, 106b of the inductor 101 are arranged in valleys symmetrically of the starry geometry, this which has an additional advantage of flexibility in subsequent molding with the lens. The sensor 100 according to the invention comprising such inductance 101 will have the advantage, compared to known sensors of the state of the art, of not forming folds or wavelets on the contact lens after its incorporation into this and may also have increased sensitivity to changes in intraocular pressure.

According to another aspect of the invention, which can be combined with the aspects described above, the sensor 100 according to the invention comprising one of the inductances 101 described previously with the aid of Figures 1a or 1b and 2 can also comprise at least one capacitor and thus realize a passive LC circuit whose resonant frequency varies in particular according to the intraocular pressure when the sensor is molded in a contact lens. According to variants of one embodiment of this aspect, it is possible to arrange at least one capacitor on the outermost circumference of the inductor 101 or on the innermost circumference of the inductor. In another variant, it is also possible to combine these two aspects and to arrange at least one capacitor outside the inductor 101 and at least one capacitor inside the inductor 101. It is then advantageous to choose the capacitive value of at least one capacitor so as to set the initial resonant frequency of the circuit in a frequency range allowed for medical applications, namely less than about 30 MHz.

Figures 3 to 5 show schematically an inductance 201 of a sensor 200 for the measurement of a physiological parameter such as intraocular pressure according to an embodiment different from that illustrated in Figures 1a, 1b and 2, illustrating another possible combination of several aspects of the present invention, but may nevertheless be combined with aspects of the embodiments described with FIGS. 1a, 1b and 2. FIG. 3 shows the sensor 200 in a three-dimensional view from above, and FIGS. 4 and 5 show details of the sensor 200, again in three-dimensional views. In addition, the sensor 200 illustrated in Figures 3 to 5 is shown flat, that is to say in its state before molding in a contact lens and bending according to the spherical cap geometry of the contact lens. According to one aspect of the invention, the sensor 200 represented in FIG. 3 comprises an inductor 201 with a first turn 202 starting from the outermost part of the inductor 201 and rotating in a first direction spiral towards the the innermost part of the inductor 201, or more generally towards the center 210 of the sensor 200.

The first turn 202 is extended by a second turn 203 which rotates in the same spiral direction, but from the inside of the sensor 200 towards the outermost part of the inductor 201, intersecting the first turn 202. The ends of the turns 202, 203 on the outer periphery of the inductor 201 form the two terminals or terminals 206a, 206b of the inductor 201. According to one aspect of the invention, the turns 202, 203 are both arranged in this same embodiment of the sensor 200. In this embodiment, the turns 202, 203 intersect at least in the two crossing zones 209a, 209e, but other embodiments of the invention could have more than crossing regions for the turns 202, 203 of the inductor 201. This geometry of interleaving of the turns 202, 203 with the terminals 206a, 206b of the inductor 201 on the outermost part of the sensor 200 allows a significant potential decline in the region around the sensor 200 and optimizes the sensitivity of the sensor 200 in this region. At the same time, the electric field lines remain substantially confined in the molded lens, so that a short circuit by the ocular fluids of the patient is avoided.

According to another aspect of the invention, which can be combined with that described above, the sensor 200 may furthermore comprise at least one capacitor and thus provide a passive LC circuit whose resonant frequency varies in particular as a function of the intraocular pressure when the sensor is molded into a contact lens. According to preferred variants of an embodiment of this aspect, it is possible to arrange at least one capacitor on the outermost circumference of the inductor 201 or on the innermost circumference of the inductor 201. inductance 201. In another variant, it is also possible to combine these two aspects and to arrange at least one capacitor outside the inductor 201 and at least one capacitor inside the inductor 201 It is then advantageous to choose the capacitive value of at least one capacitor in order to set the initial resonant frequency of the circuit in a frequency range allowed for medical applications, namely less than about 30 MHz. As for the embodiment described by means of FIGS. 1b and 2, and as shown in the detailed views of FIGS. 4 and 5, the turns 202, 203 intersect each other by means of a plurality of conductive vias 2071a, 2072a. , ..., 207 (2n) a and 2071e, 2072e, ..., 207 (2m) e, n and m being integers, interconnected by conductive traces 2081a, 2082a, ..., 208 ( n) a and 2081e, 2082e, ..., 208 (m) e arranged on a second plane of the sensor, which is a plane parallel to the first plane of the sensor 200 on which are arranged the turns 202, 203. Figure 4 illustrates a three-dimensional view of the top of the sensor 200 around the crossing zone 209e, while Figure 5 illustrates a three-dimensional view of the underside around the crossing zone 209a. Each of the crossing zones 209a, 209e comprises a plurality of crossings 2091a, 2092a, ..., 209 (n) a and 2091e, 2092e, ..., 209 (m) e between the first turn 202 and the second turn 203 of the inductor 201. It is illustrated in particular in Figures 3 to 5, according to a variant of an aspect of the invention, that one of the two turns 202, 203, here the turn 203, is composed of a series of segments 2031a, 2032a, ..., 203 (m) a and 2031b, 2032b, ..., 203 (n) b, interconnected by conductive vias 2071a, 2072a, ..., 207 () a and 2071e, 2072e, ..., 207 (2m) e and by the conductive traces 2081a, 2082a, ..., 208 (n) a and 2081e, 2082e, ..., 208 (m) e arranged in the zones of crossing 209a, 209e parallel to the respective crossings 2091a, 2092a, ..., 209 (n) a and 2091e, 2092e, ..., 209 (m) e between the first turn 202 and the second turn 203. In other embodiments, the turn 202 could be composed of such a succession of segments instead of the turn 203, and still In other embodiments, the two turns 202, 203 could be composed of such segments. For the embodiment illustrated in FIGS. 3 to 5, the integers n and m therefore correspond to the number of segments 2031a, 2032a, ..., 203 (m) a and 2031b, 2032b, ..., 203 (n). b of the turn 203 on each side of the crossing zones 209a, 209e. In the particular case of FIGS. 3 to 5, n = 8 and m = 9, so that each of the crossing zones 209a, 209e comprises respectively n = 8 or m = 9 crossings 2091a, 2092a, ..., 209 (n ) a and 2091e, 2092e, ..., 209 (m) e and conductive traces 2081a, 2082a, ..., 208 (n) a and 2081e, 2082e, ..., 208 (m) e, respectively connected to means of 2n = 16 or 2m = 18 conductive vias 2071a, 2072a, ..., 207 () a and 2071e, 2072e, ..., 207 (2m) e. However, it is obvious to those skilled in the art that the integers n and m may vary in other embodiments of the invention, depending on the number of turns of the spiral geometry of the inductor 201 and the chosen location. in the geometry of the inductor 201 to start the second turn 203 with respect to the first turn 202. Thus, in the particular case of the embodiment illustrated by Figures 1b and 2, n = m = 1 and therefore 2n = 2m Therefore, those skilled in the art will understand that the integers n and m can adopt equal integer values as in the first example or different as in the second example. It is preferable to have a dielectric medium between the conductive traces 2081a, 2082a, ..., 208 (n) a, 2081e, 2082e, ..., 208 (m) e, 213a, 213b and the first turn 202 and / or the second turn 203, especially at the crossing zones 209a, 209e. The aspects and variants described above in the context of the embodiment illustrated in FIGS. 3 and 5 can be combined with additional aspects of the invention or be taken independently of one another in order to obtain other modes. performing aspects or combinations of aspects of the invention. They can also be combined with the aspects described in the context of the embodiments illustrated in FIGS. 1a, 1b and 2. Thus, the inductance 201 of the embodiment illustrated in FIGS. 3 to 5 is of star-shaped geometry comprising a succession of branches, in particular an even number of branches, here more particularly eight branches 204a, 204b, 204c, 204d, 204e, 204f, 204g, 204h, and valleys 205a, 205b, 205c, 205d, 205e, 205f, 205g, 205h However, it is also possible that variants of this embodiment include an odd number of branches. The even numbered branch variant is preferred because the folding of the sensor 200 for molding in a contact lens is facilitated. As in the cases described with reference to FIGS. 1a, 1b and 2, in the variant with a star-shaped geometry, it is advantageous that the ends of the branches 204a, 204b, 204c, 204d, 204e, 204f, 204g, 204h and the The bottom of each valley 205a, 205b, 205c, 205d, 205e, 205f, 205g, 205h are rounded, as illustrated in Figures 3 to 5, to allow better bending of the sensor 200 for molding in a contact lens.

The dimensions of the sensor 200 may be adapted so as not to hinder the vision of a patient wearing a lens molded with such a sensor 200. In particular the distance between the center 210 of the star geometry, or the center of the sensor 200, and the end of each of the branches 204a, 204b, 204c, 204d, 204e, 204f, 204g, 204h may be substantially less than or equal to the radius of the lens, preferably between about 60 (3/0 and about 85 (3 / 0 the radius of the lens, so as not to exceed the lens after molding.Also, it is preferable that the distance between the center 210 and the bottom of each of the valleys 205a, 205b, 205c, 205d, 205e, 205f , 205g, 205h of the star geometry does not exceed about 55 (3/0 to about 75 (3/0 of the radius of the lens so as to be always less than the distance between the center 210 and the end of the branches 204a, 204b, 204c, 204d, 204e, 204f, 204g, 204h so as to respect These values are also preferable so as not to obstruct the view of the subject wearing a lens provided with such a sensor 200, especially in the dark or in low light conditions.

In the embodiment illustrated in Figures 3 to 5, the crossing zones 209a, 209e detailed in particular in Figures 4 and 5 are located in valleys 205a, 205e symmetrically opposite the inductance 201, which presents an alternative to cases 1a, 1b and 2 in which the crossing zones 109a, 109d are in branches 104a, 104d of the inductor 101. Nevertheless, in one variant of the combinations of inventive aspects leading to the embodiment illustrated in FIGS. 3 to 5, it is possible to arrange the crossing zones 209a, 209e in branches of the inductor 201, in particular symmetrically opposite branches, instead of the valleys 205a, 205e. From a practical point of view, it is possible to describe the starry geometry of the inductances 101 and 201 of the embodiments described above by means of mathematical equations, in particular using an algorithm of the above type. after using the following variables: Description of the variables: nspires number of turns of the spiral rint inner radius' spire width of a turn not pitch turn pitch angle angular rotation in radians depth of variation of the turns (e = 0 for a geometry circular) nbranch number of branches of the star Equations describing the spiral geometry: b = no / (2 7t); k = 1; I = 1; fi Calculation of the points in clockwise rotation FOR tab = 0: pasangle: (nspires * 2 ic) R = r, nt + (b * angle1 + e * cos (nbtancn * angle1)); spireX1 (k) = R * cos (angle1); spireY1 (k) = R * sin (angle1); k = k + 1; END // Calculation of the anti-clockwise rotation points to obtain the thickness of the turn FOR angle2 = (nspires * 2 10 (PaSangle * (-1)) (PaSangIe * (-1)) R = rint + (b * angle2 + e * cos (nprapph * angle2)) + 'spire * (1 + (1/2) * sin (n / 4) * abs (sin (angle2 * nprapph))); spireX2 (I) = R * cos (angle2); spireY2 (I) = R * sin (angle2); = + 1; FIN Numerical application: nspires - 18 number of turns r, nt = 3300 inner radius in pm 'turn - 70 width of one turn in pm step = 130 step pitch 2 * (2 ir / 360) no angular rotation in radians e = 800 depth of turn variation (e = 0 for circular geometry) nbranch = 8 number of branches Star geometry An inductance type inductance 201 of the embodiment illustrated in FIGS. 3 to 5 could be described by the above numerical application, in which nspire = 18 would correspond to the total number of turn turns described by the turns. 202, 203, in other words resp ectively by the turn 202 and the turn segments 203a, 203b, or by the turn 202 and the turn segments 2031a, 2032a, ..., 203 (m), 2031b, 2032b, 203 (n) b, and Ispire would correspond to the width of each of the turn elements 202, 203, respectively 203a, 203b or 2031a, 2032a, ..., 203 (m), 2031b, 2032b, 203 (n) b. Similarly, nbranch = 8 would correspond to the number of branches 204a, 204b, 204c, 204d, 204e, 204f, 204g, 204h of inductance 201. The value of r, nt would then define the interior dimensions of branches 204a, 204b, 204c , 204d, 204e, 204f, 204g, 204h and valleys 205a, 205b, 205c, 205d, 205e, 205f, 205g, 205h, and the value of e would give the depth of variation between branches 204a, 204b, 204c, 204d, 204e, 204f, 204g, 204h and valleys 205a, 205b, 205c, 205d, 205e, 205f, 205g, 205h. By choosing an inner radius r, nt = 3300 pm and a turnwidth of Ispire = 70 pm, it is therefore possible to realize an inductance of the type of the inductance 201 described above for a sensor 200 to be incorporated in a lens of contact with all the advantages described above, among others a sensor 200 whose dimensions will not obstruct the vision of the subject carrying the lens.

A similar digital application could make it possible to determine the starry geometry of an inductance of the type of the inductor 101 of the sensor 100 of the exemplary embodiments illustrated in FIGS. 1a, 1b and 2. In the case of the inductor 101, nsp , r, = 3 would correspond to the total number of turn turns described by the turns 102, 103, that is to say by the turn 102 and the turn segments 103a, 103b, and nbranch = 6 would correspond to the number of branches 104a, 104b, 104c, 104d, 104e, 104f. Other numeric values may be similar or similar to those of the previous digital application. Thus it is also possible to realize an inductance 101 for a sensor 100 to be incorporated into a contact lens with all the advantages described above. Those skilled in the art will understand that the numerical values given above are only illustrative examples of a way to determine the star geometry of inductances such as inductances 101 and 201 of the embodiments illustrated respectively in FIGS. a, 1b and 2 and Figures 3 to 5. In particular, inductances similar to the inductances 101 and 201 of the examples illustrated in Figures 1a-5 could be realized in practice with other numerical values than those given above. Those skilled in the art will appreciate that these digital applications are not restrictive of other embodiments of the invention and its variants. By its various aspects, their possible variants and combinations, the invention makes it possible to solve several problems related to the manufacture and use of passive sensors for monitoring physiological parameters such as intraocular pressure. One aspect of the invention makes it possible in particular to avoid the formation of folds and wavelets bordering the contact lenses after incorporation of the sensor which have been observed for the lenses provided with sensors known from the state of the art. An inductor, and more generally, a substantially star-shaped geometry sensor provides sufficient flexibility to bend the sensor without creating creases in the contact lens. The invention allows to play with several parameters, such as the number of branches of the star shape, or the length of the branches.

Another aspect of the invention makes it possible to avoid short circuits caused by the ocular fluids between the electric field lines observed in the known state of the art sensors, while increasing the sensitivity of the sensor with respect to known sensors of the state of the art. A sensor according to the invention therefore comprises a substantially spiral inductor employing arcuate elements starting from a first terminal on the outermost radius of the spiral, intersecting, and ending with a second terminal also arranged on the radius most at the outside of the spiral, which allowed to observe a significant potential drop in the region at the edge of the sensor, optimizing the sensitivity of the sensor in this desired region, while confining the electric field lines in the molded lens, so that a short circuit by ocular fluids is avoided. In addition, in the different aspects of the invention and their variants, it is possible to use arcuate elements preferably arranged on the same plane of the sensor, while the electrical connections between said elements are made by means of vias and electrical traces arranged on a second plane of the sensor. The conductive vias and conductive traces are then preferably arranged in the regions of intersection between the turns of the inductor. All aspects of the invention and their various variants described above can be combined to obtain more variants of a sensor according to the invention having one or more of the aforementioned advantages.

Claims (15)

REVENDICATIONS1. An intraocular pressure sensor (100, 200) for incorporation into a contact lens, comprising: an inductor (101, 201), characterized in that the inductor (101, 201) has a substantially star-shaped geometry comprising a succession of branches ( 104a, 104b, 104c, 104d, 104e, 104f) and valleys (105a, 105b, 105c, 105d, 105e, 105f). 2. Sensor (100, 200) according to claim 1, characterized in that the end of each branch (104a, 104b, 104c, 104d, 104e, 104f) and each valley (105a, 105b, 105c, 105d, 105e , 105f) is rounded. 3. Sensor (100, 200) according to any one of claims 1 or 2, characterized in that the inductor (101, 201) comprises an even number of branches (104a, 104b, 104c, 104d, 104e, 104f). preferably 6, 8 or 10 branches. 4. Sensor (100, 200) according to any one of the preceding claims, characterized in that the distance between the center of the starry geometry (110, 210) and the end of each branch (104a, 104b, 104c, 104d , 104e, 104f) is substantially less than or equal to the radius of the lens, preferably between 60 (3/0 and 85 (3/0) of the lens radius. 5. Sensor (100, 200) according to any one of the preceding claims, characterized in that the distance between the center of the starry geometry (110, 210) and the bottom of each valley (105a, 105b, 105c, 105d, 105e, 105f) between two successive branches (104a, 104b, 104c, 104d, 104e, 104f) is substantially less than or equal to the distance between the center of the starry geometry (110, 210) and the end of the two branches ( 104a, 104b, 104c, 104d, 104e, 104f) which surround it, preferably is between 55 (3/0 and 75 (3/0) of the radius of the lens. The sensor (100, 200) according to any one of the preceding claims, wherein the inductor (101, 201) comprises a first terminal (106a, 206a) and a second terminal (106b, 206b), characterized in that the first terminal (106a, 206a) and the second terminal (106b, 206b) are arranged on the outermost part of the inductor (101, 201). 7. Sensor (100, 200) according to claim 6, characterized in that the inductor (101, 201) further comprises a first turn with substantially stellar geometry (102, 202) from the first terminal (106a, 206a) on the outermost part of the inductance (101, 201) rotating in a first spiral direction towards the innermost part of the inductance (101, 201), and a second turn having a substantially star-shaped geometry (103, 203) extending the first starwheel (102, 202) in the same spiral orientation from the innermost portion of the inductor (101, 201) to the second terminal (106b, 206b) on the the outermost of the inductor (101, 201), wherein the first starry coil (102, 202) and the second starry coil (103, 203) are arranged substantially on a first plane of the sensor and intersect one another in crossing areas (109a, 109d, 209a, 209e). 8. Sensor (100, 200) according to any one of claims 6 or 7, characterized in that the first turn (102, 202) and / or the second turn (103, 203) of the inductance (101, 201 ) is / are formed (s) at least partially of a succession of segments (103a, 103b) with at least partially stellar geometry connected by conductive vias (1071a, 1072a, 1071d, 1072d). 9. Sensor (100, 200) according to claim 8, characterized in that the conductive vias (1071a, 1072a, 1071d, 1072d) are interconnected by conductive traces (1081a, 1081d) arranged in a second plane of the sensor, different from the first plane of the sensor, preferably parallel to the first plane of the sensor, and in which the conductive traces (1081a, 1081d) are preferably separated from the first turn (102, 202) and / or the second turn (103, 203) by a dielectric medium. 10. Sensor (100, 200) according to any one of claims 7 to 9, characterized in that the first turn (102, 202) and the second turn (103, 203) intersect in at least two, preferably only two, crossing zones (109a, 109d, 209a, 209e). 11. Sensor (200) according to claim 10, characterized in that the crossing zones (209a, 209e) are in valleys (205a, 205e), in particular symmetrically opposite valleys (205a, 205e), of the inductor (101, 201). 12. Sensor (100, 200) according to any one of claims 8 to 11, characterized in that the conductive vias (1071a, 1072a, 1071d, 1072d) are arranged in said crossing zones (109a, 109d, 209a, 209e). ). 13. Sensor (100, 200) according to any one of the preceding claims, further comprising at least one capacitor. A contact lens, in particular a soft contact lens, comprising a sensor (100, 200) according to any one of the preceding claims, wherein the sensor (100, 200) is molded inside the lens. 15. Contact lens according to claim 14, wherein the inductance (101, 201) is curved perpendicularly to the first plane of the sensor according to the curvature of the lens.