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    • 专利摘要:
    The invention relates to an optical device (100) with zoom variation comprising: a first deformable membrane (1), a second deformable membrane (2), a support (3) to which a respective peripheral anchor zone (1c ) of each of said membranes (1,2) is bonded, - a constant volume of a fluid (4) enclosed between the first and second membrane, - a device (5) for actuating a region (1a) of the first membrane located between the anchoring zone (1c) and a central portion (1b) of the first membrane (1), configured to deform by application of an electrical operating voltage in a single direction of deflection so to move part of the fluid volume. The central part (1b) of the first membrane (1) has a sufficient stiffness so that: - from a rest position in which the actuating device (5) is inactive, the first membrane (1) is deformed only in a first direction when applying to the actuating device (5) an actuating electrical voltage lower than a threshold and the second membrane (2) deforms to absorb the fluid displacement induced by the deformation of the first membrane (1), so as to minimize the pressure of the fluid on the first membrane, and - the actuation region (1a) of the first membrane remaining deformed in said first direction, the central portion (1b) of the first membrane ( 1) deforms in a second direction opposite to the first direction under the effect of the pressure of the fluid (4) displaced by the actuating device (5) when an electric tension is applied to the actuating device (5) higher actuating aud it threshold.
    公开号:FR3015694A1
    申请号:FR1363256
    申请日:2013-12-20
    公开日:2015-06-26
    发明作者:Sebastien Bolis
    申请人:WAVELENS；
    IPC主号:
    专利说明:

    [0001] FIELD OF THE INVENTION The present invention relates to an optical zooming device and a method of varying the focal length of such an optical device.
    [0002] BACKGROUND OF THE INVENTION In order to integrate the optical zoom function into a compact optical system comprising several lenses with fixed focal length, it may be advantageous, especially in order to minimize the thickness of the optical system, to integrate at least one optical device. with variable focal length to obtain strong focal length variations. Some optical devices alone provide a variation of magnification, others must be associated with fixed optics or other devices with variable focus to ensure the zoom function. For applications to miniature cameras, especially cameras for mobile telephony, we seek to design a compact and inexpensive optical zoom device. A device that makes it possible to work in a divergent mode or in a convergent mode is particularly advantageous since it makes it possible to benefit from a wider range of variation in the focal length.
    [0003] Various types of liquid-based variable focus devices have been developed to meet this need, for example based on electro-wetting [1] or liquid crystal [2]. Other solutions are based on the use of deformable membranes subjected to the pressure of a fluid, each membrane forming a diopter.
    [0004] Two membranes are generally used to increase the optical power of the device. In these devices, the membranes deform under the effect of the fluid pressure induced by displacement of the fluid. In some applications, each of the two membranes is actuated independently of the other, each membrane being associated with a cavity containing the fluid, which is separated from the other by a substrate, and having its own actuating device [3, 4 ]. The fluid pressure imposed on one of the membranes may thus be different from the other.
    [0005] Various lens configurations where the focal length actuators are arranged at the periphery of each membrane are shown in Figures 1A and 1B.
    [0006] FIG. 1A illustrates a convergent bi-convex lens, which may or may not be symmetrical. This device comprises a support 3 to which two deformable membranes 1, 2 are bonded in a respective peripheral anchoring zone 1c, 2c, and a rigid plate 31 extending between the two membranes. Each membrane 1, 2 defines, with the support 3 and the plate 31, a respective constant volume of a fluid 41, 42. Due to the presence of the rigid plate 31 interposed between the fluid volumes 41 and 42, the deformations of the two membranes are independent of each other. Each membrane 1, 2 is provided with an actuating device 5, 5 'arranged on a respective intermediate zone 1a, 2a between the central part 1b, 2b and the anchoring zone 1c, 2c of each membrane. The actuators 5, 5 'of the two membranes 1, 2 deflect towards the membrane and the fluid 41, 42 (in the direction of the arrows) to obtain the bi-convex configuration illustrated in FIG. 1A.
    [0007] Figure 1B corresponds to a divergent lens bi-concave, which may be symmetrical or not. The structure of the device is similar to that of the device of FIG. 1A, the actuating device 5, 5 'of each membrane being able to deflect in the opposite direction to that of FIG. 1A (in the direction of the arrows) for to obtain such a configuration.
    [0008] Since the two diopters operate independently of each other, it is also possible to obtain many other configurations of convergent lenses (convex plane or convergent meniscus) or divergent lenses (concave plane or divergent meniscus). FIGS. 2A to 2C illustrate another example of an optical device having a structure similar to that of FIG. 1A, in which the membrane 2 provides the convergent function (with a bending of the actuating device 5 'in one direction, towards the fluid) and the membrane 1 ensures the divergent function (with a deflection of the actuating device 5 in the opposite direction), each membrane being associated with an independent fluid volume 41, 42. The elements designated by the same reference signs in Figures 1A-1C and 2A-2C are similar. FIG. 2A represents the optical device at rest, taking the example of an infinite initial focal length. FIG. 2B shows the optical device actuated so as to be convergent: for this purpose, the actuating device 5 is not activated; only the actuating device 5 'is activated so as to bend towards the fluid 42. A convex plane convex lens is thus obtained. FIG. 2C shows the optical device actuated so as to be divergent: for this purpose, the actuating device 5 'is not activated; only the actuating device 5 is activated so as to bend towards the fluid 41. A concave plane divergent lens is thus obtained. In other applications, the two membranes are coupled by a constant volume of fluid enclosed between said membranes [5-10], both membranes are subjected to the same fluid pressure. Figures 3A and 3B illustrate such optical devices. With respect to the device illustrated in FIGS. 1A to 2C, the device of FIGS. 3A and 3B does not contain a plate separating the volumes of fluid associated with each membrane. The device therefore contains a single constant volume of fluid 4 mechanically coupling the membranes 1 and 2.
    [0009] In these devices, the actuators 5, 5 'of the two membranes jointly participate in modifying the fluid pressure applied to each of said membranes. When the actuating devices 5, 5 'deflect towards the fluid 4, the pressure is increased and the two membranes 1, 2 become convex (convergent device, see Figure 3A). When the actuating devices 5, 5 'deflect in the opposite direction to the fluid 4, the two membranes 1, 2 become concave (divergent device, see Figure 3B). To obtain an optical system which makes it possible, from a rest position, to have positive and negative focal length variations, the actuating devices must operate in both directions. However, such actuation is complex to implement. Indeed, the electrical voltages required for the actuators are typically greater than 30V (a voltage of + 1-40V is mentioned in [3]).
    [0010] In existing devices, thick layers of piezoelectric materials are bonded to each membrane, which involves a complex manufacturing process and imposes a number of constraints on the membrane and on the geometry of the device. However, it is possible to perform such a two-way operation using MEMS technologies. It is then necessary to use materials that have the ability to deform in both directions, but these materials (AIN for example) are less efficient in terms of actuation, or use a bimorph actuator comprising two layers of ceramic PZT ( Titano-Lead Zirconate).
    [0011] Knowing that the PZT ceramic has a high manufacturing cost, the latter option is particularly expensive. The device illustrated in FIGS. 2A to 2C may be alternately convergent and divergent, using actuators operating in a single direction.
    [0012] The disadvantage of such a device, which consists in superimposing two single-membrane devices, is that it offers much smaller focal length variations than the variations that the devices illustrated in FIGS. 1A-1B and 3A-3B allow get. Indeed, only one diopter is active in the convergent configuration, the other diopter being active in the divergent configuration. BRIEF DESCRIPTION OF THE INVENTION An object of the invention is therefore to design an optical device providing a range of variation over a wide range, allowing a simple operation (in particular using low electrical operating voltages), which is compact and simple to manufacture. According to the invention, there is provided a zoom optical device comprising: a first deformable membrane, a second deformable membrane, a support to which a respective peripheral anchoring zone of each of said membranes is bonded, constant volume of a fluid enclosed between the first and second membranes, said fluid providing a mechanical coupling of said first and second membranes; a device for actuating a region of the first membrane located between the anchoring zone and a central portion of the first membrane, configured to deform by application of an actuating electrical voltage in a single deflection direction so as to displace a portion of the fluid volume, said displacement of the fluid being capable of inducing deformation of the central portion of the first membrane, said optical device being characterized in that the central portion of the first The first diaphragm has sufficient stiffness that: - from a rest position in which the actuating device is inactive, the first diaphragm only deforms in a first direction when applying to the actuating device a actuating electrical voltage below a threshold and the second diaphragm deforms to absorb the fluid displacement induced by the deformation of the first diaphragm, so as to minimize the fluid pressure on the first diaphragm, and the actuation of the first membrane remaining deformed in said first direction, the central portion of the first membrane is deformed in a second direction opposite to the first direction under the effect of the pressure of the fluid displaced by the actuating device when applying to the actuating device an actuating electrical voltage greater than said threshold. Advantageously, the second membrane has a lower stiffness than the central portion of the first membrane.
    [0013] According to one embodiment, the optical device further comprises a device for actuating an actuation region of the second membrane located between the anchoring zone and a central part of said membrane, configured to deform by application of an electrical operating voltage. According to one embodiment, the device for actuating the second membrane is able to deform in two opposite directions depending on the electrical operating voltage applied to said device. According to one embodiment, in its rest configuration, the central portion of the first membrane is flat. According to one embodiment, the optical device comprises a substrate extending between the two membranes and comprising at least one fluid passage, so that the fluid pressure is identical on both sides of said substrate. The material of the first and / or second membrane may be a siloxane resin or a mineral material comprising silicon. According to an advantageous embodiment, the device for actuating the first membrane comprises at least one piezoelectric actuator. According to one embodiment of the invention, the first or the second membrane is reflective. The stiffness of the first membrane may advantageously be chosen so that in the absence of a fluid pressure exerted on said membrane, the application of an electrical operating voltage to the actuating device causes the deformation of the region. actuating and the central portion of the membrane, the tangents to the membrane on either side of the junction between the actuating region and the central portion being merged. According to one embodiment, the diameter of the deformable portion of the first membrane is different from the diameter of the deformable portion of the second membrane. According to another embodiment, the diameter of the deformable portion of the first membrane is identical to the diameter of the deformable portion of the second membrane. Another object relates to a method of varying the focal length of an optical device 35 comprising: a first deformable membrane, a second deformable membrane, a support to which a respective peripheral anchor zone of each of said membranes is bonded, constant volume of a fluid enclosed between the first and the second membrane, said fluid providing a mechanical coupling of said first and second membranes; a device for actuating a region of the first membrane located between the peripheral anchor zone and a central portion of said membrane, configured to deform by application of an electrical operating voltage in a single direction of deflection, said method being characterized in that it comprises: - application to the actuating device a first actuating voltage lower than a threshold, leading to deforming the first membrane in a first direction while that the second membrane is deformed to absorb the fluid displacement induced by the deformation of the first membrane so as to minimize the pressure of the fluid on the first membrane, - the application to the actuating device of a second electrical voltage d actuation greater than said threshold, leading to deforming the central portion of the first membrane in a second direction opposite to the first direction under the effect of the pressure of the fluid displaced by the actuating device, the actuation region of the first membrane remaining distorted in the first direction. According to one embodiment: at rest, the first and second diaphragms each form a plane diopter, the first actuating electrical voltage is applied so as to deform the actuation region and the central part towards the fluid, the second membrane deforming in the opposite direction to the fluid, so that the central portion of the first diaphragm forms a diverging diopter and the second diaphragm forms a convergent diopter, - the second electrical voltage is applied so as to deform the operating region towards the fluid, the displacement of the fluid inducing a deformation of the central part in the direction opposite to the fluid, so that the central part of each of the two membranes forms a convergent diopter. According to one embodiment, the diameter of the deformable portion of the first membrane is smaller than the diameter of the deformable portion of the second membrane and: at rest, the first and second diaphragms each form a diopter plane, - the first actuating electrical voltage so as to deform the actuating region and the central portion towards the fluid, the second diaphragm deforming in the opposite direction to the fluid, so that the optical device forms a divergent meniscus. According to one embodiment, the diameter of the deformable portion of the first membrane is greater than the diameter of the deformable portion of the second membrane and: - at rest the first and the second membrane each form a dioptre plane, - the first is applied actuating electrical voltage so as to deform the actuating region and the central portion towards the fluid, the second diaphragm deforming in the opposite direction to the fluid, so that the optical device forms a converging meniscus. According to one embodiment, the optical device comprises a device for actuating an actuation region of the second membrane located between the anchoring zone and a central portion of said membrane, configured to deform by application of a electrical actuation voltage and: - at rest the first and the second diaphragm each form a plane dioptre, - the first actuating electrical voltage is applied to the actuating device of the first diaphragm so as to deform the actuation region and the central portion to the fluid without applying electrical actuation voltage of the second membrane actuating device, the second membrane deforming in the opposite direction to the fluid, so that the central portion of the first membrane forms a diopter diverging and the second diaphragm forms a converging diopter, - the second actuating electrical voltage is applied to the actuating device the first diaphragm so as to deform the actuation region towards the fluid and an actuating electrical voltage is applied to the device for actuating the second diaphragm towards the fluid, so that to increase the convergence of the diopter formed by the central part of the second membrane. Finally, another object of the invention relates to a shooting device comprising an optical device as described above.
    [0014] BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the invention will emerge from the detailed description which follows, with reference to the appended drawings in which: FIGS. 1A and 1B respectively represent a section of a convergent bi-convex lens and of a known bi-concave divergent lens of the known type, FIGS. 2A to 2C show in section the various operating states of an optical device of known type that can be convergent or divergent, FIGS. 3A and 3B represent in section two operating states of an optical device of known type in which the two membranes are coupled by a volume of fluid enclosed between them, - Figure 4A illustrates the vacuum deformation (that is to say not subject to a fluid pressure) of the first membrane of an optical device according to the invention; FIG. 4B illustrates, by way of comparison, the vacuum deformation of a membrane which is not suitable for the implementation of the invention because of insufficient rigidity; FIG. 5A illustrates a configuration of an optical device according to a embodiment of the invention, wherein the diopter formed by the first membrane is divergent and the diopter formed by the second membrane is convergent; FIG. 5B presents by hatching the volumes of fluid displaced during the deformation of the membranes in this configuration; FIG. 6A illustrates a configuration of the same optical device as that of FIGS. 5A and 5B, corresponding to an electrical operating voltage plus higher than in the configuration of Figures 5A and 5B, wherein the diopter formed by the first membrane is convergent and the diopter formed by the second membrane is also convergent; FIGS. 6B and 6C show, by hatching, the volumes of fluid displaced during the deformation of the membranes in this configuration; FIG. 7A illustrates an optical device according to one embodiment of the invention, in which the geometry of the two membranes is FIG. 7B shows, by hatching, the volumes of fluid displaced during the deformation of the membranes in the configuration of FIG. 7A; FIG. 8A illustrates an optical device according to one embodiment of the invention, in which the first membrane has a diameter smaller than that of the second membrane, FIG. 8B presents by hatching the volumes of fluid displaced during the deformation of the membranes in the configuration of FIG. 8A; FIG. 9A illustrates an optical device according to a mode embodiment of the invention, wherein the first membrane has a diameter greater than that of the second membrane FIG. 9B presents by hatching the volumes of fluid displaced during the deformation of the membranes in the configuration of FIG. 9A; FIGS. 10A and 10B show two configurations of an optical device according to an embodiment in which the two diaphragms can be actuated; FIGS. 11A to 11C illustrate various possible configurations of an optical device according to the invention; FIGS. 12A and 12B illustrate other possible configurations of an optical device according to the invention; FIG. 13 illustrates the variation in optical power of the device as a function of the deflection of the first membrane; FIG. 14 illustrates the deflection of each membrane as a function of the fluid pressure; FIG. 15 schematically illustrates a device for taking view comprising an optical device according to the invention.
    [0015] For reasons of readability of the figures, the various elements illustrated are not necessarily represented on the same scale. The reference signs are used from one figure to another to designate the same elements.
    [0016] DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION FIGS. 5A, 5B and 6A-6C illustrate different operating configurations of an optical device 100 according to one embodiment of the invention. The optical device 100 has an optical axis X. The device 100 comprises two deformable membranes 1, 2, whose periphery is anchored in a sealed manner on a support 3. In this example, the support 3 is in the form of a crown ring whose center is intended to receive a volume of a fluid 4 contained in a sealed cavity defined by the two membranes 1, 2 and the support 3. The fluid 4 may be a liquid or a gas.
    [0017] The membranes 1 and 2 are then anchored on either side of the support 3. Advantageously, the membranes extend substantially parallel to each other. Each membrane comprises a respective peripheral anchoring zone 1c, 2c. Each membrane further comprises a respective central portion 1b, 2b which corresponds to an optical field of the optical device. Each membrane thus comprises a face, said inner face, which is in contact with the fluid 4, and an opposite face, said outer face, which is in contact with a second fluid, not referenced, which may be ambient air. By membrane is meant any flexible and waterproof film, so that the membrane forms a barrier between the fluid 4 and the fluid located on the opposite face of the membrane. In the case where the optical device 100 is a lens, which therefore functions in transmission, the two membranes 1, 2 are transparent, at least in their central portion 1b, 2b, to an optical beam (not shown) intended to propagate. through the lens, successively passing through the central portion of a first lens, the fluid and the central portion of the second lens. In the case where the optical device 100 is a mirror, the central part of one of the two membranes is reflective.
    [0018] Each membrane 1, 2 is able to deform in a reversible manner, from a rest position (which may be plane or not), under the action of a displacement of the fluid 4 which varies the thickness of the fluid at level of the central part of each membrane.
    [0019] The more flexible a membrane is (in other words, the lower its stiffness), the greater the deformation induced by a displacement of fluid. The fluid 4 is enclosed between the two membranes 1, 2 and provides a mechanical coupling of said membranes, so that the effect of a fluid displacement can not be evaluated independently for each of the membranes but in combination according to the respective properties of the membrane. each of the membranes. The fluid 4 is sufficiently incompressible to move towards the central part of the device when a force is applied to a membrane in the direction of the fluid, this force being applied in an intermediate portion between the anchoring zone and the central portion of the device. the membrane.
    [0020] The shape of the support 3 and the membranes 1 and 2 may advantageously have a shape of revolution around the optical axis X, but the skilled person may choose any other form without departing from the scope of the present invention. In the device, at least one of the two membranes is provided with an actuating device. By convention, it is considered here that the first membrane, referenced 1, has an actuating device 5; the second membrane, referenced 2, may or may not be equipped with an actuating device. In the embodiment illustrated in FIGS. 5A-5B and 6A-6C, the second membrane does not have an actuating device, so that its possible deformation results solely from the displacement of the fluid 4. Moreover, although the membrane 1 actuated is positioned on the upper face of the device, it goes without saying that it could also be positioned on the underside of the device, the membranes 1 and 2 being interchanged. The actuating device is designed to deform in a single direction, that is to say, according to the configuration of the device, to the fluid (in order to successively obtain a divergent device and then converge) or the opposite fluid (in order to successively obtain a convergent device and then divergent). Insofar as it seeks to vary the focal length of the optical device without deflecting the incident beam, the actuating device is adapted to deform uniformly over the entire circumference of the actuating region. An actuating device particularly adapted to obtain a single direction of operation is based on piezoelectric technology. It will be recalled that a piezoelectric actuator comprises a block of piezoelectric material totally or partially sandwiched between two electrodes intended, when energized, to apply an electric field to the piezoelectric material. This electric field is used to control a mechanical deformation of the block of piezoelectric material. The block of piezoelectric material may be monolayer or multilayer and extend beyond an electrode. The actuating device may comprise a single actuator in the form of a ring or of several distinct actuators regularly distributed over the circumference of the membrane. In this regard, reference can be made to a detailed description of such actuating devices in the documents FR2919073, FR2950154 and FR2950153. The actuating device is arranged in a region 1a of the first membrane, called the operating region, located between the peripheral anchoring zone 1c and the central portion 1b of said membrane. Optionally, the actuating device may extend in part over the peripheral anchoring zone. In the figures described below, the actuating device is shown on the outer face of the first membrane. However, the invention is not limited to this embodiment but also allows the actuating device to be arranged on the inner face of the first membrane, or even inside the first membrane. In the embodiment illustrated in FIGS. 5A-5B and 6A-6C, it is assumed that at rest, that is to say when the actuating device 5 of the first membrane is not activated, the first and the second membrane are flat (configuration not shown). Nevertheless, one could design each of the two membranes so that it has at rest a concave or convex shape without departing from the scope of the present invention. In this embodiment, the membrane 2 is more flexible than the central portion 1b of the membrane 1. FIGS. 5A and 5B correspond to a first mode of operation of the optical device 100. FIG. 5A shows the deformation membranes 1 and 2 under the effect of a displacement of the fluid 4 provided by the application to the actuating device 5 of an actuating voltage lower than a determined threshold. The actuating device 5 deforms the actuation zone 1a of the membrane 1 towards the fluid 4 (direction of the arrows) and, insofar as its stiffness is sufficient, the central portion 1b of the membrane 1 deforms in the same way. As long as the fluid pressure necessary to deform the membrane 2 is too weak to deform the central portion 1b of the membrane 1, the diopter formed by the first membrane is concave / divergent and the diopter formed by the second membrane is convex / convergent .
    [0021] As can be seen in FIG. 5B, the volume of fluid displaced by the deformation of the membrane 1 (represented by the hatched area V1) is equal to the volume absorbed by the deformation of the membrane 2 (represented by the hatched area V2). FIGS. 6A and 6B correspond to a second mode of operation of the optical device 100. From a certain fluid pressure, which is generated by the application, to the actuating device 5 a higher actuating voltage at the threshold mentioned above (the direction of actuation being always towards the fluid, but schematized by the double arrows to represent the increase of the amplitude of deformation due to the increase of the electric tension of actuation compared to the 5A), the central portion 1b of the membrane 1 deforms significantly under the effect of the fluid pressure. As can be seen in FIG. 6A, the actuation region 1a of the membrane 1 remains deformed in the same direction as in FIG. 5A, but the central portion 1b of said membrane 1 is deformed in a direction opposite to the direction FIG. 5A under the effect of the pressure of the fluid 4 displaced by the actuating device 5. The retention of the fluid volume is maintained but, in this operating mode, it integrates the volume associated with the deformation of the part central 1b of the first membrane.
    [0022] In FIG. 6A, the hatched region VO represents the volume of fluid displaced by the actuation of the membrane 1 relative to the rest position, assuming that no fluid pressure is exerted on said membrane. In FIG. 6B, the hatched regions V1 and V2 represent the volumes of fluid absorbed by the deformation of the two membranes. The sum of the fluid volumes represented by the V1 and V2 regions is equal to the volume of fluid represented by the VO region due to the retention of the fluid volume. In this second mode of operation, the diopter formed by the membrane 1 is plane, or even convergent. In this second mode of operation, the two dioptres participate in the focal length of the device and allow to obtain larger focal length variations. The electrical voltage threshold mentioned below can be determined experimentally by varying the operating voltage of the diaphragm actuating device and measuring the electrical voltage from which a reversal of the curvature of the part is observed. central of the first membrane.
    [0023] To be able to obtain such an inversion of the deformation of the central part of the first membrane between the first and the second mode of operation, the actuating device being always deformed in the same direction, the first membrane must have a sufficiently large stiffness.
    [0024] FIGS. 4A and 4B show two examples of membranes having different stiffnesses, represented here anchored on a support but not subject to a fluid pressure. It is assumed in these two cases that the membrane is flat at rest. In FIG. 4A, the membrane 1 has a stiffness sufficiently large for the implementation of the invention, which results in the fact that when the actuating device 5 of said membrane is activated, the central portion 1b of the membrane 1 is deformed in the extension of the intermediate zone 1a on which the actuating device 5 is arranged. In the case where the membrane has a uniform stiffness throughout its deformable portion, the tangents to the membrane 1 of the part and other of the junction between the actuating region la and the central portion 1b are merged. FIG. 4B, on the other hand, illustrates a membrane having a stiffness that is too low for the implementation of the invention. In contrast to the membrane of FIG. 4A, this membrane only deforms in the intermediate zone 1a where the actuating device is located, but its central portion 1b does not deform and remains flat, being content to translate with respect to his rest position. More precisely, the stiffness of the membrane 1 is defined so that the curvature obtained when the membrane is actuated (see FIG. 4A) is in accordance with the optical properties (divergence, convergence, etc.) desired for the device (see step 1 of the dimensioning example developed below).
    [0025] In the presence of the fluid 4, a sufficiently stiff membrane 1 such as that of FIG. 4A induces a pressure in the fluid, linked to the force deployed by the actuating device 5, and consequently a movement of the fluid. The coupling of such a membrane with the membrane 2 which is also deformable provides the two operating modes shown in Figures 5A and 6A. To ensure that the membrane 1 has a sufficiently high stiffness, the skilled person can use finite element modeling software (Comsol for example) to determine the vacuum deformation (without fluid pressure) of the membrane under the effect of the actuation (configuration of Figure 4A).
    [0026] To size the membranes 1 and 2 and adjust their stiffness to obtain the desired deformations, the skilled person can use a circular membrane deformation model such as that described in [11]. The relation between a fluid pressure p applied uniformly on the membrane and various parameters representative of the membrane is given by the formula: h 2.83 E co2) P4 R2 6 ° ((Yr + 4 (1-v2) R2 where: h is the thickness of the membrane, R is the radius of the membrane subjected to the pressure p, a, is the residual stress in the membrane, w is the deflection at the center of the membrane, v is the coefficient of E is the Young's modulus of the material constituting the membrane of the material constituting the membrane and for each of the two membranes, the constituent material, the geometry and the residual stress in the membrane can be adjusted to obtain a stiffness and deformations consistent with the expectations described above.
    [0027] At a given pressure, the conservation of the fluid volume is easily calculated from the deformations of each membrane. Finally, the optical power (i.e., the inverse of the focal length) of a two-membrane optical device is given by the following formula, using the thin-lens approximation: = (n - 1) (- R1 - -R2) where: n is the refractive index of the fluid, R1 is the radius of curvature of the spherical diopter constituted by the first membrane (optical central part), R2 is the radius of curvature of the spherical diopter constituted by the second membrane (optical central part), In terms of sign convention for R1 and R2, in the case of a biconvex lens R1> 0 and R2 <0 (the optical power is positive). In the first mode of operation which corresponds to an actuating electrical voltage of the actuating device 5 of the diaphragm 1 below the aforementioned threshold, numerous optical configurations can be obtained according to the respective dimensioning of the first and second diaphragm. Figures 7A and 7B illustrate an embodiment of the optical device 100 in which the membranes 1 and 2 have a substantially identical geometry, including substantially equal diameters.
    [0028] It is specified that "diameter" means the diameter of the deformable portion of a membrane, comprising the central portion and, where appropriate, the operating zone, but excluding the peripheral anchoring zone which is fixed. The device 100 is here represented in its first mode of operation. In the case where the geometries of the membranes 1 and 2 are substantially identical (essentially as regards their diameter), the curvatures of the two diopters are substantially equal.
    [0029] The resulting optical power is therefore not very high but it can be finely adjusted. Moreover, such an optical configuration has advantages other than the only variation in optical power. Indeed, by dimensioning the device by appropriately adjusting the fluid thickness between the two membranes, and the focal length associated with each of the two membranes, it is possible, for example, to obtain an afocal optical device having an effect on the magnification. According to other embodiments, it is possible to adapt the geometry of the two membranes (in particular the diameter) to preferentially obtain a divergent meniscus configuration or meniscus convergent in the first mode of operation. FIGS. 8A and 8B illustrate an optical device 100 in which the membrane 1 has a diameter smaller than that of the membrane 2. In order to obtain, as in FIGS. 8A and 8B, a diverging lens in the first operating mode, it is necessary to to minimize the convergent curvature of the diopter formed by the membrane 2 and to maximize the curvature of the diopter formed by the diaphragm 1. At a constant fluid volume 4 (the hatched regions V1 and V2 in FIG. 8B representing equal volumes), this is obtained divergent configuration by increasing, with respect to the device of Figure 6A, the diameter of the membrane 2 and decreasing the diameter of the membrane 1 which is actuated. Conversely, to obtain, as in FIGS. 9A and 9B, a convergent lens in the first mode of operation, it is necessary to maximize the convergent curvature of the diopter formed by the membrane 2 and to minimize the curvature of the diopter formed by the membrane 1. of constant fluid 4 (equality of the volumes represented by the hatched zones V1 and V2 in FIG. 9B), such a divergent configuration is obtained by decreasing, with respect to the device of FIG. 7A, the diameter of the membrane 2 and increasing the diameter of the membrane 1 which is actuated. The optical power of the devices illustrated in FIGS. 8A and 9A is therefore much higher than that of the device of FIG. 7A. In the second mode of operation, in which the electric actuation voltage of the actuating device of the first membrane is greater than the aforementioned threshold (double arrows), numerous optical configurations can also be obtained according to the respective dimensioning of the first and the second membrane. For example, the different geometrical configurations of the optical device illustrated in FIGS. 7A, 8A and 9B make it possible to obtain, in the second mode of operation, very different convergent optical powers (convex plane lens, symmetrical biconvex lens or biconvex lens). asymmetric).
    [0030] According to one embodiment of the invention, to increase the optical power of the device in the second mode of operation, it may be advantageous to also provide the second membrane with an actuating device. FIGS. 10A and 10B illustrate an optical device 100 comprising a device 5 'for actuating the membrane 2 arranged on an area 2a of the intermediate membrane between the peripheral anchoring zone 2c and the central portion 2b of the membrane 2. in the embodiments described above, the membrane 1 is always provided with the actuating device 5. In the first operating mode (electrical actuation voltage of the device 5 below the aforementioned threshold), the actuating device 5 'n is not activated and the membrane 2 therefore behaves as described above with reference to FIG. 5A (see FIG. 10A). In the second mode of operation (see FIG. 10B), the actuating device 5 'is activated to increase the pressure in the fluid 4 and to accentuate the convergent deformation of the diopter formed by the membrane 2 with respect to the configuration of the FIG. 6B. The actuating device 5 'of the second membrane may be similar to that of the first membrane, that is to say based on the same operating technique in a single direction.
    [0031] However, it is also possible to design the device 5 'so that, unlike the device 5, it can be deformed in two opposite directions. Thus, in a first phase of operation, this device 5 'is activated in the same direction as that of the device 5, thus opposed to the fluid 4, to absorb the volume of fluid displaced by the membrane 1 while maintaining a diopter corresponding to the second membrane unchanged (advantageously plane). Then, in a second phase of operation, the device 5 'is activated in the opposite direction, namely towards the fluid 4, to accentuate the focal length variation of the optical device. Figs. 11A to 11C illustrate further configurations of the optical device, in which both membranes are actuated. The device is shown in its second mode of operation. In FIG. 11A, the actuated membrane 1 forms a plane diopter and the membrane 2, which is actuated in the opposite direction to that of the membrane 1, forms a convergent meniscus.
    [0032] In FIG. 11B, the actuated membrane 1 forms a convergent meniscus and the membrane 2, which is actuated in the opposite direction to that of the membrane 1, forms a convergent meniscus.
    [0033] In FIG. 11C, the actuated membrane 1 forms a meniscus more convergent than that of FIG. 11B, and the membrane 2, which is actuated in the opposite direction to that of the membrane 1, forms a convergent meniscus only in FIG. 11B . In the examples described above, the first membrane formed a divergent diopter in the first mode of operation, then a plane diopter and then converge in the second mode of operation. However, as illustrated in FIGS. 12A and 12B, it is also conceivable, by implementing an actuating device 5 operating in a single opposite direction to the fluid 4, contrary to the preceding examples, that the first membrane 1 forms a convergent diopter in the first mode of operation (see Figure 12A) then a plane dioptre then diverge in the second mode of operation (see Figure 12B). There is therefore a very large number of possible combinations, among which the skilled person can define the one that best suits the intended application and the desired performance. Preferably, the optical axes of the two membranes are aligned, but it is also possible in other embodiments not to align said optical axes. Furthermore, the optical device may comprise a stack of more than two membranes, the membranes being mechanically coupled by means of a volume of fluid maintained between two consecutive membranes, the nature of the fluid being able to be different between two pairs of membranes. Optionally, the optical device may comprise a substrate having an optical function (eg, diaphragm, infrared filter, etc.) between the two membranes. The substrate then delimits two fluid cavities. To maintain the mechanical coupling exerted by the fluid on the two membranes, it is ensured that the substrate allows the passage of fluid from one cavity to another, so as to obtain an equal fluid pressure in the two cavities. For this purpose, one or more orifices of sufficient size are provided in the substrate. The optical device can be made by microelectronics techniques well known to those skilled in the art, in particular thin layer deposition techniques of chemical vapor deposition type, physical vapor phase deposition, electrodeposition, epitaxy, thermal oxidation, evaporation, rolling of films. Furthermore, the anchoring of the membranes on the support may involve bonding techniques. The membranes 1, 2 may be made from organic materials such as polydimethylsiloxane, polymethylmethacrylate, polyethylene terephthalate, polycarbonate, parylene, epoxy resins, photosensitive polymers, silicones, or mineral materials such as silicon, silicon oxide, silicon nitride, polycrystalline silicon, diamond carbon. The membranes may consist of a single layer of the same material or a stack of layers of different materials.
    [0034] Moreover, the membranes may exhibit identical stiffness at any point on their surface, or, on the contrary, may present different stiffnesses in different regions. In this case, it is the central part which must respect the conditions of stiffness exposed above. The fluid 4 may be a liquid such as propylene carbonate, water, a liquid index, an optical oil or an ionic liquid, a silicone oil, an inert liquid with high thermal stability and low saturation vapor pressure. The fluid may optionally be a gas such as air, nitrogen or helium mainly for an optical device operating in reflection. If the optical device operates in transmission, those skilled in the art will choose the refractive index of the fluid according to the desired optical performance. According to an advantageous embodiment of the invention, the optical device may incorporate means for compensating for a variation in the focal length due to a variation in the temperature to which the device is subjected. Indeed, a difference in coefficient of thermal expansion between the different components may lead to a change in the focal length of the optical device when the temperature varies by a significant amplitude. Such compensation means are described in detail in WO 2011/032925. Exemplary embodiment of an optical device The device 100 may for example be manufactured according to the following method. First, two subsets each formed of a silicon substrate and a membrane are produced. In this respect reference may be made to document FR 2 962 557, which describes a method of manufacturing such a subassembly. The material of each membrane is advantageously a polymer (such as a siloxane resin) or a mineral material (such as silicon oxide, polycrystalline silicon, silicon nitride). The manufacture of each membrane involves controlling the residual stress in the membrane, so that it is not excessively compressive (to avoid any buckling of the membrane) nor excessively tensile (to avoid penalizing its deformation in operation). Advantageously, the residual stress in each membrane is slightly tensile. The device for actuating the first membrane is advantageously a piezoelectric device, preferably based on PZT.
    [0035] Then, the two subassemblies are assembled by encapsulating the fluid. This technique is conventionally used in the manufacture of LCD screens and will not be described in detail here. Advantageously, an adhesive is used to assemble the two substrates and to guarantee the distance separating them. The fluid, for example a liquid index or an optical oil, is previously dispensed on one of the substrates. Finally, the two membranes are successively released by etching the silicon substrates in the central part and the actuation zone.
    [0036] Example of dimensioning of the first and second membranes of the optical device. A method of designing an optical device which has a zero optical power at rest and which, during the actuation of the first membrane, becomes successively divergent and then convergent, is described below.
    [0037] Step 1: Choosing the Radius of the First Membrane To achieve the desired optical performance, a first step is to define the radius of the first membrane and the required deflection and curvature. For example, with a membrane of 1 mm radius, a deflection of the 85 μm membrane corresponds to a focal variation of -85 diopters with a liquid of index 1.5 (with respect to a plane rest position at infinite and for a deflection of the membrane towards the liquid). In this first step, the desired optical power variations must be overstated because they will ultimately be less important. Indeed, they are penalized by the effect of the second membrane: cf. the transition from -85 diopters to finally -7 diopters after the sizing calculation in the example developed below). In a first step, the width of the actuating region on the membrane is determined approximately according to the total radius of the membrane. For a radius of 1 mm, this width of the actuation region at 500 μm is first fixed. From the geometric elements defined above (radius of the membrane, width of the actuation region) and according to the intrinsic properties of the first membrane (Young's modulus, Poisson's ratio, internal stress) and its thickness the actuation of this membrane to obtain the deflections and curvatures referred to is dimensioned from the techniques of the state of the art. Indeed, the deformation of the first membrane in the absence of fluid shown in Figure 4A is obtained by the effect of (s) actuator (s) located (s) on the periphery of this membrane. An example of biasing the actuating device to obtain such a deformed is a bending moment applied to the membrane. The moment to apply on the membrane according to its geometry (thickness, diameter) and its properties (Young's modulus, internal stress) to obtain the desired deformation without fluid can be determined by using the equations detailed in [13] or by performing finite element simulations (with COMSOL software for example). The dimensioning of the piezoelectric actuation can then be carried out using the techniques of the state of the art.
    [0038] In the case of a piezoelectric actuation, one can for example refer to the model detailed in [14] or [15]. Thus, for a given actuating device (and an electrical voltage applied to this device), it is possible to determine the curvature of the associated membrane. Since the present invention is not related to the actuation technology, the dimensioning of this part of the device, which is within the abilities of those skilled in the art, is not described in detail here. In the example developed here, the properties of the first membrane are a Young's modulus of 100 MPa, a Poisson's ratio of 0.35, a thickness of 200 μm and an internal stress of 0.5 MPa.
    [0039] Step 2: Choice of the radius of the second membrane In a first step, it is assumed that, under the effect of the actuation of the first membrane, all the fluid displaced by the first membrane deforms the second membrane. The radius retained for the second membrane has a direct influence on the optical power of the device. To have a divergent device, it is necessary that the radius of the second membrane is greater than that of the first membrane, as shown in Figure 8A. For a radius of the second membrane of 1.1 mm, the optical power of the device associated with a deflection of the first 85 μm membrane is no longer -85 diopters but -26 diopters.
    [0040] Step 3: choice of the mechanical properties of the second membrane The properties of the second membrane (Young's modulus E, Poisson's ratio v, internal stress crr) are chosen so that its behavior is non-linear given its radius and deflections required. It is indeed necessary that during the actuation of the first membrane and under the effect of the fluid pressure, the deflection of the second membrane saturates somewhat to allow the deformation of the center of the first membrane (counter reaction of the fluid on the first membrane). By calling w the deflections of <0 2,83.E R2 Taking into account the data retained in the first two stages, for the second membrane a mineral material of Young's modulus 230 GPa, of Poisson's ratio 0.35 is chosen. and internal stress 0.5 MPa. Once the intrinsic properties of the second membrane have been defined, it is then sufficient to fix its thickness to determine the corresponding range of fluid pressure in the cavity over the entire operating range of the first membrane. An iterative approach may be necessary to set the thickness of the second membrane as a compromise must be found. Indeed, if the thickness of the second membrane is too small, then only the second membrane deforms under the effect of the fluid pressure induced by the actuation of the first membrane. The optical device will then always be divergent (no feedback from the central part of the first membrane).
    [0041] If the thickness of the second membrane is too large, then the second membrane does not deform sufficiently and the feedback of the central portion of the first membrane occurs from the beginning of the actuation of the first membrane. The optical device will then always be convergent. Note however that the power provided by the actuator must be sufficient to generate the required pressure in the cavity. In the present example, the thickness retained for the second membrane is 10 μm. Step 4: Updating the deformations of each of the membranes With the fluid pressure as previously calculated, the deformations of the second membrane and of the central part of the first membrane under the pressure of the fluid and the volumes of fluid are calculated. associates. Step 5: Update of the Actuation of the First Membrane The associated deflection of the first membrane is then recalculated, this time taking into account the counter-reaction and the deformation of the central part of the first membrane. In the present example, the deflection initially calculated at 85 pm increases to 87 pm. An update of the data determined in step 1 (sizing and width of the actuating device, intrinsic properties of the first membrane) can be optionally performed in this step. second membrane and R its radius, the non-linearity becomes preponderant in the deflection of the second membrane when: 4.6,. (1 - v2) - The result obtained by such an approach is illustrated in Figure 13, which presents the optical power variation of the device (in diopters) as a function of the deflection w of the first membrane, in the case of actuation in the absence of the fluid. Figure 14 illustrates the deformation of the membranes under uniform fluid pressure. The upper curve w2 represents the deformation of the membrane 2, the lower curve w1, the deformation of the membrane 1. The intermediate curve w3 represents the deformation of the membrane 2 by readjusting its diameter to the dimension of the diameter of the central part of the membrane. membrane 1, so as to allow the comparison of stiffnesses of equal size An optical device as described above can advantageously be incorporated in a shooting device comprising a zoom function. As a purely illustrative example, FIG. 15 shows the structure of a shooting device comprising fixed-focus lenses S1, S2, liquid lenses L1, L2 and a filter F, the image plane being designated by the reference I.
    [0042] At least one of the liquid lenses L1, L2 of this device may be an optical device according to the invention. There are many other possible configurations of such cameras and the invention is not limited thereto.
    [0043] REFERENCES [1] Zoom Lens Design for a Slim Mobile Camera Using Liquid Lens, Journal of the Korean Physical Society, Vol. 54, No. 6, June 2009, pp. 2274-2281 [2] Nonmechanical bifocal zoom telescope, Optics Letters, Vol. 35, No. 15, August 1, 2010 [3] Fluidic Zoom Lens system using two single chamber IEEE MEMS 2011, Cancun, January 23-27 35 [11] The design, Manufacturing and Testing of Corrugated Silicon Nitride Diaphragms, Journal of Microelectromechanical Systems, Vol. 3, No. 1, March 1994 [12] S. Timoshenko, Theory of Plates and Shells [4] Fluidic Zoom-Lens-on-a-Chip With Wide Field-of-View Tuning Range, IEEE 2004, pp. 1041-1135 [5] JP 2000-081504 [6] EP 2 034 338 [7] JP 11-133210 [8] FR 2 919 073 [9] FR 2 950 153 [10] FR 2 950 154 [13] A novel ultra-planar, long-stroke and low-voltage piezoelectric micromirror, Journal of Micromechanics and Microengineering 20 (2010) [14] Analysis of the deflection of a circular plate with an annular piezoelectric actuator, Sensors and actuators A133 (2007) .5
    权利要求:
    Claims (18)
    [0001]
    REVENDICATIONS1. An optical device (100) with zooming variation comprising: - a first deformable membrane (1), - a second deformable membrane (2), - a support (3) to which a respective peripheral anchor zone (1c) of each of said membranes (1,2) is bonded, - a constant volume of a fluid (4) enclosed between the first and the second membrane, said fluid (4) providing a mechanical coupling of said first and second membranes, - a device (5) actuating a region (1a) of the first membrane located between the anchoring zone (1c) and a central portion (1b) of the first membrane (1), configured to deform by application of a tension electrical actuator in a single direction of deflection so as to move a portion of the fluid volume, said displacement of the fluid being capable of inducing a deformation of the central portion (1 b) of the first membrane, said optical device ( 100) being characterized in that the central portion (1b) of the first diaphragm (1) has sufficient stiffness that: - from a rest position in which the actuating device (5) is inactive, the first diaphragm (1) is deforms only in a first direction when applying to the actuating device (5) an actuating electrical voltage lower than a threshold and the second membrane (2) is deformed to absorb the fluid displacement induced by the deformation of the first membrane (1), so as to minimize the pressure of the fluid on the first membrane, and 25 - the operating region (1a) of the first membrane remaining deformed in said first direction, the central portion (lb) of the first membrane (1) is deformed in a second direction opposite to the first direction under the effect of the pressure of the fluid (4) displaced by the actuating device (5) when applying to the actuating device (5) a higher actuating voltage threshold. 30
    [0002]
    2. Device according to claim 1, characterized in that the second membrane (2) has a lower stiffness than the central portion (lb) of the first membrane. 35
    [0003]
    3. Device according to one of claims 1 or 2, characterized in that it further comprises an actuating device (5 ') of an actuation region (2a) of the second membrane located between the zone d anchoring (2c) and a central portion (2b) deladite membrane, configured to deform by application of an electric actuation voltage.
    [0004]
    4. Device according to claim 3, characterized in that the actuating device (5 ') of the second membrane (2) is able to deform in two opposite directions depending on the actuating voltage applied to said device.
    [0005]
    5. Device according to one of claims 1 to 3, characterized in that in its rest configuration the central portion (1b) of the first membrane (1) is flat.
    [0006]
    6. Device according to claim 5, characterized in that it comprises a substrate extending between the two membranes and comprising at least one fluid passage orifice, so that the fluid pressure is identical on both sides. said substrate.
    [0007]
    7. Device according to one of claims 1 to 6, characterized in that the material of the first and / or the second membrane is a siloxane resin or a mineral material comprising silicon.
    [0008]
    8. Device according to one of claims 1 to 7, characterized in that the actuating device (5) of the first membrane comprises at least one piezoelectric actuator.
    [0009]
    9. Device according to one of claims 1 to 8, characterized in that the first or the second membrane is reflective. 25
    [0010]
    10. Device according to one of claims 1 to 9, characterized in that the stiffness of the first membrane is chosen so that in the absence of a fluid pressure exerted on said membrane, the application of a voltage electrical actuation device to the actuating device (5) causes the deformation of the actuation region (1a) and the central portion (1b) of the membrane, the tangents to the membrane on both sides of the the junction between the actuating region (1a) and the central portion (1b) being merged.
    [0011]
    11. Device according to one of claims 1 to 10, characterized in that the diameter of the deformable portion (1a, 1b) of the first membrane is different from the diameter of the deformable portion (2a, 2b) of the second membrane.
    [0012]
    12. Device according to one of claims 1 to 10, characterized in that the diameter of the deformable portion (1a, 1b) of the first membrane is identical to the diameter of the deformable portion (2a, 2b) of the second membrane.
    [0013]
    13. Shooting device comprising at least one optical device (100) according to one of claims 1 to 12.
    [0014]
    14. A method of varying the focal length of an optical device (100) comprising - a first deformable membrane (1), - a second deformable membrane (2), - a support (3) to which a respective peripheral anchoring zone ( 1c, 2c) of each of said membranes (1, 2) is bonded, - a constant volume of a fluid (4) enclosed between the first and the second membrane, said fluid (4) providing a mechanical coupling of said first and second membranes, - a device (5) for actuating a region (1a) of the first membrane (1) located between the peripheral anchoring zone (1c) and a central portion (Ib) of said membrane, configured to deforming by application of an electrical operating voltage in a single direction of deflection, said method being characterized in that it comprises: - the application to the actuating device (5) of a first electrical voltage of actuation below a threshold, leading to deformation of the first membrane (1) in a first direction while the second membrane (2) is deformed to absorb the fluid displacement induced by the deformation of the first membrane (1) so as to minimize the pressure of the fluid on the first membrane, - The application to the actuating device (5) of a second actuating voltage greater than said threshold, leading to deform the central portion (1b) of the first membrane in a second direction opposite to the first direction under the effect of the pressure of the fluid displaced by the actuating device (5), the actuating region 30 (1a) of the first membrane remaining deformed in the first direction.
    [0015]
    15. Method according to claim 14, characterized in that: - at rest the first and the second membrane each form a dioptre plane, - the first actuating electrical voltage is applied so as to deform the actuating region (1a ) and the central part (1b) towards the fluid (4), the second membrane being deformed in the opposite direction to the fluid (4), so that the central part of the first membrane forms a diverging diopter and the second membrane forms a converging diopter, - the second electric voltage is applied so as to deform the actuation region (1a) towards the fluid, the displacement of the fluid (4) inducing a deformation of the central part (1b) in the opposite direction to the fluid (4), so that the central portion of each of the two membranes forms a convergent diopter.
    [0016]
    16. The method of claim 14, characterized in that the diameter of the deformable portion (1a, 1b) of the first membrane is smaller than the diameter of the deformable portion (2a, 2b) of the second membrane and in that: - at rest, the first and second diaphragms each form a plane diopter, - the first actuating electrical voltage is applied so as to deform the actuating region (1a) and the central part (1b) towards the fluid (4) , the second membrane deforming in the opposite direction to the fluid (4), so that the optical device forms a divergent meniscus.
    [0017]
    17. The method of claim 14, characterized in that the diameter of the deformable portion (1a, 1b) of the first membrane is greater than the diameter of the deformable portion (2a, 2b) of the second membrane and in that: at rest, the first and second diaphragms each form a plane diopter, the first actuating electrical voltage is applied so as to deform the actuation region (1a) and the central part (1b) towards the fluid (4); ), the second membrane deforming in the opposite direction to the fluid (4), so that the optical device forms a converging meniscus.
    [0018]
    18. The method of claim 14, characterized in that the optical device comprises an actuating device (5 ') of an actuating region (2a) of the second membrane located between the anchoring zone (2c) and a central part (2b) of said membrane, configured to deform by application of an electrical operating voltage and in that: - at rest the first and the second diaphragm each form a plane diopter, - the first voltage is applied electric actuator to the actuating device (5) of the first diaphragm so as to deform the actuation region (1a) and the central portion (1b) to the fluid (4) without applying an actuating electrical voltage of the actuating device (5 ') of the second membrane, the second membrane deforming in the opposite direction to the fluid (4), so that the central part of the first membrane forms a diverging diopter and the second membrane forms a diopter converge, the second actuating electric voltage is applied to the actuating device (5) of the first diaphragm so as to deform the operating region (1a) towards the fluid (4) and applying an electrical actuation voltage to the device actuating (5 ') the second membrane towards the fluid, so as to increase the convergence of the diopter formed by the central portion of the second membrane.
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    同族专利:
    公开号 | 公开日
    CN106062586B|2017-10-24|
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    CN106062586A|2016-10-26|
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    法律状态:
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    2016-11-11| PLFP| Fee payment|Year of fee payment: 4 |
    2017-07-14| TP| Transmission of property|Owner name: WEBSTER CAPITAL LLC, US Effective date: 20170614 |
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    优先权:
    申请号 | 申请日 | 专利标题
    FR1363256A|FR3015694B1|2013-12-20|2013-12-20|OPTICAL DEVICE WITH FOCAL VARIATION|FR1363256A| FR3015694B1|2013-12-20|2013-12-20|OPTICAL DEVICE WITH FOCAL VARIATION|
    US15/106,800| US9869802B2|2013-12-20|2014-12-18|Optical device with focal length variation|
    CN201480068912.0A| CN106062586B|2013-12-20|2014-12-18|Optical device with focal length variations|
    PCT/EP2014/078516| WO2015091834A1|2013-12-20|2014-12-18|Optical device having a variable focal length|
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