• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to an optical device (100) with variable aperture, comprising: - a deformable membrane (1) comprising an optical central zone (1a), - a support (10, 12) to which a peripheral anchoring zone (1c) said membrane (1) is bonded, - a first cavity filled with a constant volume of a first fluid (2) transparent in a determined wavelength range, said cavity being delimited at least in part by a first face of said membrane (1) and a wall of the support (10), - at least one actuating device (5) of a region (1b) of the membrane situated between the peripheral anchoring zone (1c) and the zone optical center (1a) of the diaphragm, configured to flex said region (1b) of the diaphragm by applying an actuating electrical voltage so as to move a portion of the volume of the first fluid (2) towards the center or towards the periphery of the first cavity, said fluid displacement being intended for deforming the central zone (1a) of the membrane, said optical device (100) being characterized in that it further comprises a constant volume of a liquid (3) opaque in said determined wavelength range, in contact at least locally with a second face of the membrane (1) opposite to the first face and with a second fluid (4) transparent in said determined wavelength range and immiscible with said opaque liquid (3).
    公开号:FR3037152A1
    申请号:FR1555035
    申请日:2015-06-03
    公开日:2016-12-09
    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 a variable aperture optical device, also known as a diaphragm, and to a method of manufacturing such a device. BACKGROUND OF THE INVENTION A diaphragm is a mechanical element interposed in the path of a light beam in an optical system to define the amount of light transmitted as well as the opening of the system. Such a device is particularly used in high performance imaging systems because it can provide light flow control functions or depth of field adjustment. It can also block the diffracted rays in the optical system and minimize the aberrations of the optical assembly.
    [0002] The iris diaphragm described in US 21470 [1] is still widely used in recent and advanced optical systems. It consists of an assembly of movable slats in a variable number depending on the size of the objective. A mechanism rotates the slats and thus allows to adjust the opening. Several limitations are associated with this type of diaphragm.
    [0003] First of all, it is a complex and expensive solution. The complexity of the mechanical structure (movement mechanism of the slats) causes assembly difficulties. In addition, to obtain a quasi-circular opening (generally necessary for an optical system), it is necessary to integrate a sufficient number of movable slats. The cost of manufacturing such a diaphragm is high and this technological solution is therefore expensive. On the other hand, the electrical power consumed by such a device is high. Indeed, the force required for the opening change is impacted by the friction between the moving mechanical parts. It is therefore necessary to use powerful motors to modify the aperture.
    [0004] Moreover, the complex mechanical structure and the motors used make such a device particularly bulky. Finally, the wear of moving mechanical parts limits the reliability of the diaphragm over time. Keeping the same approach as the iris diaphragm, new mechanical solutions have been developed in recent years [2, 3]. Among these mechanical solutions, some are based on actuation by MEMS (microelectromechanical systems) to optimize the size and reduce consumption. This is the case in the references [2, 3] mentioned above.
    [0005] However, these solutions do not overcome all the limitations of the iris diaphragm. Indeed, these mechanical diaphragm technologies all retain a high footprint and manufacturing complexity mainly related to the very principle of operation. In addition, most of them do not provide a quasi-circular aperture required for optical systems. For several years, new non-mechanical solutions have been developed. In particular, several fluidic solutions have been developed as an alternative to mechanical solutions. A state of the art of variable opening diaphragms with a fluidic structure is detailed in Philipp Müller's thesis [4], a brief synthesis of which is given below with reference to Figs. 12A-12G. Each of these figures represents the same respective device in two aperture configurations. In the technological solution presented in FIG. 12A, the optical device 200 comprises a plurality of transparent elastomer half-spheres 201 pressed against a PMMA substrate 202 by encapsulating an opaque liquid 203. The pressure and the quantity of opaque liquid located between the half-spheres 201 and the substrate 202 are adjusted so as to let more or less the light and thus adjust the opening diameter. For this purpose, the device comprises an opaque liquid inlet 204 coupled to a system such as a pump (not shown) external to the device 200. This device 20 is particularly interesting for creating a network of diaphragms. However, such a device is not integrated, the pressurizing system of the opaque liquid being offset to the outside of the device, so that this solution is bulky. The device 300 illustrated in FIG. 12B comprises a deformable membrane 301 and a constant volume of an opaque liquid 302 contained in a first cavity 25 delimited in part by the membrane 301. On the face opposite the opaque liquid 302, the membrane 301 is in contact with a gas 303, for example air, contained in a second cavity. Said second cavity comprises a gas inlet 304 coupled to a remote system (not shown) for pressurizing said gas. More or less significant pressure is applied to the membrane 301 via the gas 303 introduced or removed from the cavity by the inlet 304. The opaque liquid is expelled by the membrane, varying the aperture of the diaphragm. We find the same disadvantage as the previous solution (non-integrated solution) due to the remote pressurization system. The device 400 illustrated in FIG. 12C comprises an opaque liquid 401 35 trapped between a glass substrate 402 and a deformable membrane 403 actuated by an annular piezoelectric actuator arranged at the periphery of the membrane. Under the effect of the actuator, the opaque liquid 401 is driven from the center of the device and the center of the membrane is gradually plated on the substrate 402. This solution is integrated, the opaque liquid 401 being encapsulated at constant volume without it is necessary to provide a liquid inlet / outlet and an external pressure system). However, the bulk remains important (of the order of 25 mm side). A major disadvantage of this solution is the poor resulting optical quality. Indeed, when the membrane 403 is pressed against the substrate 402, it can remain locally a small amount of opaque liquid which penalizes the optical quality of the assembly. In addition, the solid / solid interface between the membrane and the glass generally induces a large wavefront error and poor optical quality of the diaphragm pass portion. Once the membrane 403 and the substrate 402 come into contact, the adhesion between the two respective materials may complicate or even prevent the reverse operation and the return of the opaque liquid on all or part of this zone. The device 500 illustrated in FIG. 12D comprises a plurality of concentric microchannels 501 and an arrival 502 of opaque liquid 503. Like the devices of FIGS. 12A and 12B, this solution is not integrated.
    [0006] The device 600 illustrated in FIG. 12E comprises an opaque liquid 601 and a liquid 602 transparent to the light beam to be transmitted, as well as two inputs (601a, 602a) / outlets (601b, 602b) for each of said liquids. This system is very complex and only allows for small variations in aperture. In addition, the volume of liquid in the device is not constant and systems external to the device are necessary for the operation to ensure laminar flow of the two liquids. In the examples illustrated in FIGS. 12F and 12G, the device 700, respectively 800 comprises two liquids, one opaque and the other transparent to the light beam to be transmitted and electrodes for adjusting the wettability of one of said liquids. The operating principle in these two cases is based on electro-wetting, a technique well known in the field of fluidics. In the case of FIG. 12F, an ITO transparent electrode 701 is sufficient to vary the wettability of the opaque liquid 703 (and thus its radius of curvature) with respect to a hydrophobic dielectric material 702 and to open more or less the central zone of the device (the transparent liquid being designated by the reference 704). In the case of FIG. 12G, the principle is the same but the single electrode is replaced by several interdigitated electrodes 801 in order to better control the shape of the interface between the respectively transparent 803 and opaque 804 liquids (the hydrophobic dielectric being designated by reference 802). In both cases, the solution is integrated (liquids are encapsulated at constant volume, no need for input / output or external complementary system).
    [0007] The drawbacks relating to these two solutions are the significant thickness of the device (typically 2 mm) and the high power supply voltage required (typically 100 V). This last characteristic makes the use and control of the device more complex and has a significant impact on the cost of the solution.
    [0008] SUMMARY OF THE INVENTION An object of the invention is therefore to design a variable aperture optical device that is more compact than existing devices, is inexpensive to manufacture and involves low power consumption.
    [0009] According to the invention, there is provided a variable aperture optical device, comprising: - a deformable membrane comprising an optical central zone, - a support to which a peripheral anchoring zone of said membrane is bonded, - a first filled cavity a constant volume of a first transparent fluid 10 in a determined wavelength range, said cavity being delimited at least in part by a first face of said membrane and a wall of the support, - at least one device of actuating a region of the membrane located between the peripheral anchoring zone and the optical central zone of the membrane, configured to flex said region of the membrane by applying an actuating electrical voltage so as to displace a portion the volume of the first fluid towards the center or towards the periphery of the first cavity, said displacement of fluid being intended to deform the central zone of the membrane said optical device being characterized in that it further comprises a constant volume of an opaque liquid in said determined wavelength range, in contact at least locally with a second face of the membrane opposite the first face and with a second transparent fluid in said determined wavelength range and immiscible with said opaque liquid. Particularly advantageously, the volume of opaque liquid is chosen so that: in a rest situation where no electrical voltage is applied to the actuating device, the opaque liquid covers at least a portion of the membrane so as to providing an opening having a first diameter, and - in an actuation situation where a non-zero electrical voltage is applied to the actuator, the central portion of the diaphragm having a different curvature of the curvature at rest, the opaque liquid covers at least a portion of the membrane so as to provide an opening having a second diameter different from the first diameter. The opening of this optical device may possibly be zero, in which case the optical device completely closes the optical field and can thus be likened to a shutter ("shutter" according to the English terminology). According to other advantageous features of the invention, taken alone or in combination: the device further comprises a second cavity opposite to the first cavity relative to the membrane, said second cavity containing the opaque liquid and a constant volume second transparent fluid; the opaque liquid and the second transparent fluid have substantially the same density; the first and second transparent fluids have substantially the same refractive index; the first and the second cavity have a transparent wall opposite the membrane; The transparent wall of the first and / or second cavity comprises an optical filter on its face opposite to the cavity; the transparent wall of the first and / or second cavity comprises a fixed optic on its face opposite to the respective cavity; the transparent wall of the first and / or second cavity comprises a variable focus device; said wall may have a central opening and said variable-focus device comprises: a deformable membrane closing said opening, a peripheral zone of the deformable membrane being anchored to said wall; at least one device for actuating a region the membrane located between the peripheral anchoring zone and the central zone of the membrane, configured to flex said region of the membrane by applying an electrical operating voltage so as to move a portion of the volume of the fluid towards the center or towards the periphery of the cavity; The membrane comprises a stiffening structure comprising cells which delimit, in the central optical zone of said membrane, at least two deformable regions; the second transparent fluid is arranged in the second cavity in the form of a plurality of elementary volumes each arranged facing a respective cell 30; the second transparent fluid is arranged in the form of a single continuous volume facing the cells; the second transparent fluid is arranged on the wall of the second cavity opposite to the deformable membrane in the form of a plurality of elementary volumes; The actuating device is piezoelectric. Another object relates to a method of manufacturing such a variable aperture optical device. Said method comprises the following steps: - providing a variable-focus device comprising the deformable membrane, the actuating device and the first transparent liquid in the first cavity, - dispensing a determined volume of the opaque liquid on the deformable membrane. Particularly advantageously, in the case where the optical device is provided with a second cavity containing the opaque liquid and the second transparent fluid, the method comprises the following steps: - supply of the optical device with variable focal length obtained by the method such as as described above, - providing a second substrate and dispensing the second transparent fluid on said second substrate in the form of at least one drop, - bonding the second substrate to the optical device with variable focal length, so as to encapsulating the second transparent fluid and the opaque liquid between the second substrate and the deformable membrane.
    [0010] BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the invention will be apparent from the following detailed description, with reference to the accompanying drawings, in which: FIGS. 1A and 1B are sectional views of an optical device according to a Embodiment of the invention, respectively at rest and in the actuated state, FIG. 2 is a view similar to FIG. 1B, on which the displacements of the first transparent fluid and the opaque liquid have been represented in FIG. 3A to 3C are cross-sectional views of an optical device according to one embodiment of the invention in which the opening has a non-zero diameter at rest, respectively at rest and in two possible actuation configurations, - Figures 4A to 4C are sectional views of an optical device according to different embodiments incorporating various additional features, - FIGS. 5A and 5B are sectional views of an optical device according to one embodiment of the invention in which the opaque liquid and the second transparent fluid are not encapsulated in a cavity, respectively at rest and in the state. FIGS. 6A to 6D illustrate different configurations of the optical device according to the invention at rest, FIGS. 7A and 7B are sectional views of an optical device at rest according to two embodiments of the invention in FIG. wherein the wettability of the second transparent fluid with respect to the wall of the second cavity is different, FIGS. 8A and 8B are sectional views of an optical device comprising an array of diaphragms according to one embodiment. of the invention in which the membrane comprises a stiffening structure and the second transparent fluid is arranged in the form of a network of droplets, respectively at rest and in the actuated state, FIGS. 9A and 9B are sectional views of an optical device comprising an array of diaphragms according to one embodiment of the invention in which the membrane comprises a stiffening structure and the second transparent fluid is arranged in the form of a single continuous volume, respectively at rest and in the 10 actuated state, - Figures 10A and 10B are sectional views of an optical device comprising an array of diaphragms according to an embodiment of the invention wherein the second fluid transparent is arranged in the form of a network of droplets, respectively at rest and in the actuated state, FIGS. 11A to 11E illustrate different stages of the manufacture of a variable aperture optical device according to an embodiment of FIG. FIGS. 12A to 12G illustrate variable aperture optical devices belonging to the state of the art. For reasons of readability of the figures, the devices are not necessarily shown in scale. From one figure to another, identical reference signs designate similar elements, which are therefore not described in detail in each new figure. DETAILED DESCRIPTION OF THE INVENTION FIGS. 1A and 1B illustrate an embodiment of an optical device 100 with variable aperture according to the invention, respectively at rest (that is to say in the absence of application of FIG. an electrical voltage), providing in this case a zero opening, and in the actuated state (an actuating electrical voltage being applied), providing in this case an opening having a non-zero optical diameter D.
    [0011] Said device 100 comprises a deformable membrane 1 comprising a central zone 1a which defines an optical field of the device and a support 10, 12 to which a peripheral anchoring zone 1c of said membrane is bonded. The membrane and a wall of the support define at least in part a first cavity which is filled with a constant volume of a first transparent fluid 2 in a determined wavelength range. Said wavelength range typically comprises the range of wavelengths that must be transmitted through said optical device. The membrane 1 is in contact, by a first main face, with the first fluid 2. The membrane is also transparent in said wavelength range. By membrane is meant any flexible and waterproof film, so that the membrane forms a barrier two fluids located on either side of the membrane.
    [0012] The first transparent fluid 2 is sufficiently incompressible to move towards the central part of the first cavity when a force is applied to the membrane in the direction of said fluid (and vice versa, towards the periphery of the first cavity when applies a force on the membrane in a direction opposite to said fluid), this force being applied in an intermediate portion between the anchoring zone and the central part of the membrane. The shape of the support and the membrane may advantageously have a shape of revolution around the optical axis of the optical device, but the skilled person may choose any other form without departing from the scope of the present invention. On the other hand, the second major face of the diaphragm 1 - opposite to the first face - is in contact with a constant volume of a liquid 3 opaque in said determined wavelength range. Said opaque liquid is also in contact with a second transparent fluid 4 in said determined wavelength range and immiscible with said opaque liquid. In the embodiment illustrated in FIGS. 1A and 1B, the opaque liquid 3 and the second transparent fluid 4 are contained together in a second cavity located on the other side of the first cavity with respect to the membrane 1. The second transparent fluid 4 then has a constant volume. However, as will be seen in another embodiment described below (see FIGS. 5A-5B), the opaque liquid and the second transparent fluid are not necessarily contained in a specific cavity. It is indeed possible that the opaque liquid is kept in contact with the second main face of the membrane because of its wettability vis-à-vis the material of the membrane, and the second transparent fluid is ambient air. The optical device 100 also comprises at least one device 30 for actuating a region 1b of the membrane - called the operating region - located between the peripheral anchoring zone 1c and the central optical zone 1a of the membrane. Said actuator 5 is configured to flex said membrane region 1b by applying an actuating electrical voltage so as to move a portion of the volume of the first transparent fluid towards the center or periphery of the first cavity , said fluid displacement being intended to deform the central zone of the membrane by modifying the fluid pressure exerted on said central zone. Those skilled in the art know different actuating devices that can be used to actuate membranes.
    [0013] These devices are based on various technologies, among which include piezoelectric actuation, electrostatic actuation, electromagnetic, thermal or based on electro-active polymers. In this respect, reference can be made to a detailed description of such actuating devices implemented in variable-focus optical devices described in documents [5] - [10]. The choice of actuation technology and the dimensioning of the actuator depends on the expected performance (eg power consumption), the stresses to which it will be subjected during the operation of the device, as well as the voltage considerations. actuation to apply. For example, a particularly effective actuator relies 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 powered, 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. Preferably, PZT is chosen as the piezoelectric material. The actuating device may comprise a single actuator in the form of a ring or of several distinct actuators (for example in the form of beams) regularly distributed over the circumference of the membrane. Optionally, the actuators may be capable of bending in two opposite directions. The actuating device can be arranged on the inner face of the membrane, on the outer face or inside the membrane. Optionally, the actuating device may extend in part over the peripheral anchoring zone.
    [0014] At rest (FIG. 1A), the membrane 1 is flat and the opaque liquid 3 forms a substantially uniform layer covering the second face of the membrane 1. In this situation, the opaque liquid prevents any incident radiation on the device 100 from being transmitted. In other words, the radius of the diaphragm thus formed is zero. When an electrical voltage is applied to an actuating device (FIG. 1B), the first transparent fluid 2 deforms the center of the membrane. Indeed, said fluid is driven in the center of the first cavity by the actuating device 5, exerts pressure on the central portion of the membrane and thus changes its radius of curvature.
    [0015] Inversely, the opaque liquid 3 is driven towards the periphery of the membrane 1, in the operating region 1b. From a certain electrical voltage (whose value depends on the volume of opaque liquid and the geometry of the membrane), the deflection of the actuating device 5 is large enough to accommodate enough opaque liquid 3 to clear the center of the membrane. The central deformation of the cumulative membrane to the flow of opaque liquid towards the periphery of the membrane makes it possible to progressively clear the center of the device while letting the membrane 1 come into contact with the second transparent fluid 4.
    [0016] The opening of diameter D thus created allows the incident radiation to pass. The more the actuation is accentuated (by increasing the applied voltage), the greater the opening. As best seen in FIG. 2, which represents the same device as FIG. 1B, the arrows A represent the displacement of the first transparent fluid 2 in the first cavity, and the arrows B represent the displacement of the opaque liquid 3 which in results in the second cavity. Compared with existing solutions, the invention makes it possible to cumulate numerous advantages: the solution is totally integrated, that is to say without any external element such as a pump or the like and thus has a small bulk (of 3 to 10 mm side for example), - the proposed optical interface is of good quality. Indeed, the solid / fluid interface between the membrane and the second transparent fluid is compatible with a satisfactory wavefront error, the thickness of such a device is optimized (typically 400 pm to 700 pm) the actuation voltage required remains low (typically 15V for a piezoelectric actuator) and the associated power consumption can be extremely low (of the order of 0.1 pW), the response time corresponding to this invention is high (typically a few ms), - the cost of manufacture can be very competitive enjoying a collective manufacturing (waferlevel type). In the example illustrated in FIG. 1A, the device at rest (0 V) has no optical aperture (zero diameter). However, it is quite possible that the idle device (0 V) has an opening of non-zero diameter OD, as illustrated in FIG. 3A. In this case, this optical aperture can be increased to a diameter D1> OD (FIG. 3B) or decreased to a diameter D2 <OD (FIG. 3C) by applying an electric voltage to the actuating device, depending on the design of the actuation and its direction of deflection. In the example illustrated in FIGS. 1A and 2A, the first cavity is delimited by the membrane 1 and a first substrate 11 connected to the membrane by a peripheral support 5 10. Similarly, the second cavity is delimited by the membrane 1 and a second substrate 13 connected to the membrane 1 by a peripheral support 12. The anchoring zone of the membrane is included between the peripheral supports 10 and 12. Said first and second substrates 11, 13 are transparent in the length range of wave in which the optical device 100 is to transmit a light beam. Said substrates may be, for example, parallel-faced glass slides. Advantageously, at least one of said substrates 11, 13 can also include optical filter functions, optical power device and / or zooming.
    [0017] Thus, in the embodiment of FIG. 4A, the first substrate 11 is provided, on its face opposite the first cavity, with an optical filter 110, anti-reflection and / or infrared. In the embodiment of FIG. 4B, the first and second substrates 11, 13 are each provided with a respective fixed optic 111, 130 which further provides constant optical power to the device 100. embodiment of Figure 4C, the first substrate 11 has a central opening 112 which is closed by a deformable membrane 1 '. The membrane 1 'is of the same type as the membrane 1 but may have different dimensions and / or mechanical properties. The peripheral zone 1c 'of the membrane 1' is anchored between the substrate 11 and the peripheral support 10. Furthermore, a device 5 'for actuating the membrane 1' is arranged in a region 1b 'intermediate between the central portion 1 'of the membrane 1' and the peripheral anchoring zone. The device 5 'can be of the same type as the device 5 or be based on another actuation technology. The diaphragm 1 'and its actuating device 5' make it possible to vary the focal length of the device 100. Indeed, as a function of the electrical operating voltage applied to the device 5 ', a part of the first transparent fluid can be driven out. towards the center or to the periphery of the first cavity, and thus to modify the curvature of the central portion 1 a 'of the membrane 1'. Naturally, the functionalities present in the embodiments of FIGS. 4A-4C may be combined with one another or incorporated into only one of the substrates without departing from the scope of the present invention.
    [0018] The volume of opaque liquid and the wettability of said liquid with respect to the membrane are chosen to allow the operation described above, namely a variation between: a rest situation where no electrical voltage is applied to the actuating device 5, the opaque liquid then covering at least a portion of the membrane so as to provide an opening having a first diameter (zero or not), and - an actuation situation where a non-zero voltage is applied to the actuating device, the central portion of the membrane then having a different curvature of the curvature at rest, the opaque liquid covering at least a portion of the membrane so as to provide an opening having a second diameter (null or not) different from the first diameter (higher or lower than this). The opaque liquid is for example a liquid or an oil comprising pigments and / or dyes in an amount sufficient to block the incident light beam. For example, the opaque liquid may be chosen from the following liquids: propylene carbonate, water, a liquid of index, an optical oil or an ionic liquid, a silicone oil, an inert liquid with a high thermal stability and at low saturation vapor pressure. The wettability of the membrane opaque liquid can be adjusted by selecting a material suitable for the membrane and / or by applying hydrophobic or hydrophilic surface treatments to the membrane. Such treatments are known per se and will not be described in detail here. For example, reference may be made to the following documents: [11] for the effect of plasma treatments; [12] for the effect of surface condition and roughness of materials; [13] for examples of materials (such as the particularly hydrophobic Cytop TM and hydrophilic SiO 2).
    [0019] In an embodiment illustrated in FIGS. 5A and 5B, the opaque liquid is not encapsulated in a dedicated cavity and is merely in contact with the ambient air, which constitutes the second transparent fluid mentioned above. This embodiment can be obtained simply by depositing the opaque liquid on the outer face of the membrane of an optical device with variable focal length.
    [0020] The spreading of the opaque liquid 3 on the membrane 1 can be adjusted and controlled as a function of the volume of deposited liquid, its wettability on the membrane, the preparation of the membrane surface, its structuring or the initial deformation. of the membrane. As mentioned above, the configuration of the opaque liquid at rest is not necessarily a layer of uniform thickness. On the other hand, the deformable membrane is not necessarily flat in the rest situation. Finally, the position of the actuating device illustrated in the various figures is not limiting. Thus, the actuators can be deflected up or down at rest regardless of the curvature of the central portion of the membrane. FIGS. 6A-6D illustrate in a nonlimiting manner various configurations of the device 100 at rest, that is to say in the absence of application of an electrical operating voltage. It should be noted that these configurations may also be encountered in one embodiment in which constant volumes of the opaque liquid and the second transparent fluid are encapsulated in a cavity. In the case of FIG. 6A, the wettability of the opaque liquid with respect to the membrane - which is flat in this embodiment - and the peripheral support 12 10 is such that the opaque liquid 3 does not form a protective layer. uniform thickness but a layer of concave shape whose thickness is greater at the periphery of the membrane than in the center. The opaque liquid layer 3 being continuous, the opening of the optical device 100 is zero. In the case of FIG. 6B, the wettability of the opaque liquid with respect to the membrane - which is flat in this embodiment - and the peripheral support 12 is such that the opaque liquid 3 does not form a protective layer. uniform thickness but a convex-shaped layer whose thickness is greater in the center of the membrane than on the periphery. The opaque liquid layer 3 being continuous, the opening of the optical device 100 is zero.
    [0021] In the case of FIG. 6C, the membrane is not flat but its central portion 1a has a concavity in which the opaque liquid 3 is received. The surface of the opaque liquid 3 opposite to the membrane is itself flat. The opaque liquid layer 3 being continuous, the opening of the optical device 100 is zero. In the case of FIG. 6D, the membrane is convex in its central part 1a, so that the opaque liquid 3 extends on either side of the top of the central portion 1a. The opening of the optical device 100 is therefore non-zero. However, this embodiment may be sensitive to gravity. Indeed, depending on the opaque liquid volume, the geometry of the membrane and the wettability between the opaque liquid and the deformable membrane, such an embodiment can generate a device having different optical performance depending on its orientation. To avoid this problem and limit the effects of gravity on the electro-optical performance of the device, a transparent fluid of the same density as the opaque liquid can advantageously be used.
    [0022] Moreover, the embodiment of FIGS. 5A and 5B may also have another disadvantage. Indeed, the potential difference in refractive index between the first transparent fluid and the ambient air causes a variation in the focal length of the device coupled to the optical aperture variation.
    [0023] To avoid such an effect, the first and second transparent fluids may be chosen to have identical refractive indices (for example using the same gas or the same liquid). This also makes it possible to avoid overcoming the focal length variation due to the deformation of the membrane between the state of rest and the state of actuation (see FIGS. 1A and 1B for example), if the variation focal length is not desired and that one only wishes to vary the aperture. To simultaneously optimize the transmission of the assembly, it is also possible to choose one or more transparent fluid (s) having a refractive index similar to or close to the membrane and the substrate (s).
    [0024] For these reasons, a preferred embodiment of the invention relates to an optical device in which the second transparent fluid is encapsulated at a constant volume in a second cavity with the opaque liquid. Thus, it is possible to choose the second transparent fluid (advantageously identical to the first transparent fluid) and the behavior of the opaque liquid under the effect of gravity is better controlled.
    [0025] To form such a cavity, a second substrate is advantageously used as shown in FIGS. 1A to 4C. At rest (zero actuating voltage), the rest position of the membrane as well as the respective volumes of opaque liquid and second fluid and their position in the optical device determine an initial opening of the device.
    [0026] To facilitate opening variation and to adapt the accessible aperture range, various configurations are possible in addition to the configurations shown in Figs. 6A-6D described above. FIGS. 7A and 7B illustrate two embodiments of an optical device 100 at rest (zero actuating voltage). In both cases, the membrane 1 is flat at rest. In the case of Figure 7A, the second transparent fluid 4 has a greater wettability vis-à-vis the second substrate 13 as in the case of Figure 7B. This results in a smaller connection angle between the second transparent fluid volume and the second substrate surface. As a result, in the case of FIG. 7A, there is no opening of the optical device 100 while the opening has a non-zero diameter OD 30 in the case of FIG. 7B. The second substrate 13 may be functionalized to determine the spreading of the second transparent fluid on contact. In terms of functionalization, mention may especially be made of any localized surface treatment intended to adjust the wettability of the second fluid on the second substrate. It is also possible to envisage the local supply of hydrophilic / hydrophobic material on the second substrate. A third embodiment makes it possible to produce a network of diaphragms with variable aperture.
    [0027] For this purpose, as illustrated in FIGS. 8A-8B, the membrane 1 comprises a stiffening structure 14 which delimits, in the central part of the membrane, at least two deformable elementary regions and which defines the mechanical behavior of the membrane. (Especially its stiffness) in the regions of the central part of the membrane extending between said elementary deformable regions. According to one embodiment, the stiffening structure may comprise a plurality of ribs that extend perpendicularly to the surface of the membrane. Alternatively, the stiffening structure may comprise a layer extending over the central portion of the membrane and having openings defining at least two deformable regions of the membrane. The use of a stiffening structure in the form of ribs is particularly preferred for producing a large number of elementary deformable regions in the central part of the membrane. The small thickness of the ribs makes it possible to maximize the number of distinct deformable regions in the central part of the membrane. Conversely, the use of a layered stiffening structure having apertures is preferred for making a small number of elemental deformable regions. Advantageously, the stiffening structure is arranged so as to form cells, the portion of membrane located inside each cell being deformable. Each portion of membrane located inside a cell 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 first transparent fluid, which The fluid thickness at the central portion of each membrane is varied. Said membrane portions may have an identical stiffness from one region of the membrane to the other or on the contrary have a different stiffness, said stiffness may in particular be adjusted by a local change in thickness or material of the membrane.
    [0028] The opaque liquid is in contact with the deformable membrane, for example on the side of the stiffening structure 14. The second transparent fluid 4 (which in this case is a liquid) is disposed on the second substrate 13 before assembly of the device 100 under the droplet array form facing the cell network of the deformable membrane. This droplet arrangement is obtained by locally adjusting the wettability of the second transparent fluid with respect to the second substrate. Thus, in each cell, an array of elementary optical devices with variable aperture is formed.
    [0029] At rest (Figure 8A), the opaque liquid 3 covers the entire surface of each cell. Each elementary optical device then has a zero opening. Under the application of an electrical operating voltage (FIG. 8B), each elementary deformable region of the membrane deforms as a result of the displacement of the first transparent fluid 2 by the actuating device 5. As a result, the opaque liquid is driven towards the periphery of each cell, thus allowing the membrane to be brought into contact with the second transparent fluid and thus to provide a non-zero opening of diameter OD. In the example illustrated in FIG. 8B, the opening diameter OD is identical for all the elementary diaphragms of the network being actuated. However, by adjusting the volume and / or the shape of the droplet network of the second transparent fluid, different opening diameters can be obtained on the diaphragm network during actuation. According to another embodiment illustrated in FIGS. 8A-8B, the network of diaphragms can be obtained without having the second transparent fluid in the form of a network. By integrating the second fluid in one piece, a diaphragm network can also be realized. As can be seen in FIG. 9A, which represents the optical device 100 at rest, the second transparent fluid 4 is in the form of a continuous layer 20 covering the surface of the second substrate 13. The opaque liquid 3 covers the surface of the membrane in all the cells defined by the stiffening structure 14. Under the application of an electrical operating voltage (FIG. 9B), each elementary deformable region of the membrane is deformed following the displacement of the first transparent fluid 2 by 5. The result is that the opaque liquid is driven towards the periphery of each cell, thus allowing the membrane to be brought into contact with the second transparent fluid and thus to provide a non-zero opening at least in certain cells. . In the example illustrated in FIG. 9B, the opening diameter of the network of diaphragms is not identical from one cell to the other. Thus, an aperture with a diameter D2 is obtained in the cells located in the center of the membrane, a diameter D1 less than D2 is obtained in the cells surrounding said central cells, and no opening is obtained in the cells. located on the periphery of the network. However, adjusting the volume or the shape of the spreading of the second transparent fluid, one can obtain the same opening diameter on the diaphragm network 35 during actuation. Another solution for obtaining a network of diaphragms having different diameters in operation situation is to use an optical device 100 without the stiffening structure 14 and to dispose the second transparent fluid 4 in a network of droplets. FIGS. 10A and 10B illustrate such a device 100 respectively at rest and in the actuated state.
    [0030] At rest, the membrane 1 is flat and the opaque liquid covers the entire surface of the membrane 1. The optical device therefore has a zero opening. Under the effect of an actuating electrical voltage, the central portion of the membrane deforms and comes into contact with at least the second transparent fluid droplets 4 located in the center of the second substrate 13. In this case, the devices Elementary optics have an opening of non-zero diameter, the larger the diameter is that the elementary optical device is close to the center of the device 100. In contrast, for the peripheral optical devices located at the periphery, the membrane 1 remains in contact with the opaque liquid 3, so that said devices have a zero opening.
    [0031] The optical device as described above can be manufactured using microfabrication techniques. In particular, the manufacturing method may comprise the following steps. With reference to FIG. 11A, there is provided a variable-focus device comprising the deformable membrane 1 anchored between the peripheral supports 10, 12, the actuating device 5 and the first transparent liquid 2 encapsulated between the membrane 1, the peripheral support 10 and the first substrate 11. The manufacture of such a device is known in itself, in particular documents [5] - [10]. Then, with reference to FIG. 11B, a given volume of the opaque liquid 3 is dispensed onto the deformable membrane 1. A preliminary surface treatment can be implemented if necessary in order to optimize the wettability of the opaque liquid on the membrane. deformable. Referring to FIG. 11C, there is provided the second substrate 13 on which a bead of peripheral adhesive 14 is deposited, for example by screen printing, and the second transparent fluid 4 (here, a liquid) is dispensed onto the second substrate in the form of a single drop (case of Figure 11C) or a network of drops (not shown) according to the embodiment considered. Said substrate may have undergone a surface treatment adapted to adjust the wettability of the second transparent fluid. Next, with reference to FIG. 11D, the second substrate 13 is glued by means of the cord 14 to the variable focus device of FIG. 11B so as to encapsulate the opaque liquid 3 and the second transparent fluid 4. The process of FIG. encapsulation used is well known in the state of the art, including methods used to encapsulate liquid crystals in LCD screens. The process described in Figure 11D is known as "One Drop Filling". In the case where the second transparent fluid is a gas, a conventional bonding method is used. Said bonding may be non-hermetic if said fluid is air (the air can freely enter or leave the second cavity.) In the case where the second transparent fluid is different from the ambient air, said bonding must instead be hermetic.
    [0032] The second transparent fluid 4 and the opaque liquid 3 being immiscible, they form two distinct entities in the cavity thus created. The optical device 100 illustrated in FIG. 11E is then obtained. The invention therefore provides a compact variable aperture optical device, low power consumption and easy to manufacture using collective microsystems 10 processes. In this respect, such a device is particularly suitable for miniature cameras for mobile telephony. Other advantageous applications concern the industry, the medical field, the automobile, security and defense.
    [0033] The present invention may also find applications in the field of lighting or display. REFERENCES [1] US21470 20 [2] "Sliding-blade MEMS iris and variable optical attenuator", Journal of Micromechanics and Microengineering, 14: 1700-1710, 2004 [3] US 2015/037024 [4] Thesis by Philipp Müller, " Tunable optofluidic apertures ", Research in Microoptics, Volume 11, edited by Prof. Dr. Hans Zappe, Department of Microsystems 25 Engineering - IMTEK, University of Freiburg, 2012, section 1.2 [5] FR 2919073 [6] FR 2919074 [7] FR 2930352 [8] FR 2938349 30 [9] FR 2950153 [10] FR 2950154 [11] "Wettability Tests of Polymer Films and Fabrics and Determination of Their Surface Energy by Contact-Angle Methods", Daphne Pappas, Craig Copeland, Robert Jensen, ARL-TR-4052, March 2007 35 [12] "Wettability Switching Techniques on Superhydrophobic Surfaces ", Nanoscale Res Lett (2007) 2: 577-596 [13]" Electrowetting: from basics to applications ", J. Phys .: Condens. Matter 17 (2005) R705-R774
    权利要求:
    Claims (17)
    [0001]
    REVENDICATIONS1. Optical device (100) with variable aperture, comprising: - a deformable membrane (1) comprising an optical central zone (1a), - a support (10, 12) to which a peripheral anchoring zone (1c) of said membrane (1 ) is connected, - a first cavity filled with a constant volume of a first fluid (2) transparent in a determined wavelength range, said cavity being delimited at least in part by a first face of said membrane (1 ) and a wall of the support (10), - at least one actuating device (5) of a region (1b) of the membrane located between the peripheral anchoring zone (1c) and the central optical zone (1a). ) of the membrane configured to flex said region (1b) of the membrane by applying an actuating electrical voltage to move a portion of the volume of the first fluid (2) toward the center or periphery of the first cavity, said displacement of fluid being intended to deform the central zone trale (1a) of the membrane, said optical device (100) being characterized in that it further comprises a constant volume of a liquid (3) opaque in said determined wavelength range, in contact at least locally with a second face of the membrane (1) opposite to the first face and with a second fluid (4) transparent in said determined wavelength range and immiscible with said opaque liquid (3).
    [0002]
    2. Device according to claim 1, characterized in that the volume of opaque liquid (3) is chosen so that: - in a rest situation where no voltage is applied to the actuating device (5), the liquid opaque material (3) covers at least a portion of the membrane (1) so as to provide an opening having a first diameter, and - in an actuation situation where a non-zero voltage is applied to the actuating device (5) the central portion (1a) of the membrane having a curvature different from the curvature at rest, the opaque liquid (3) covers at least a portion of the membrane (1) so as to provide an opening having a second diameter different from the first diameter.
    [0003]
    3. Device according to one of claims 1 or 2, characterized in that it further comprises a second cavity opposite to the first cavity relative to the membrane (1), said second cavity containing the opaque liquid (3) and a constant volume of the second transparent fluid (4). 3037152 20
    [0004]
    4. Device according to claim 3, characterized in that the opaque liquid (3) and the second transparent fluid (4) have substantially the same density.
    [0005]
    5. Device according to one of claims 3 or 4, characterized in that the first and second transparent fluids (2, 4) have substantially the same refractive index.
    [0006]
    6. Device according to one of claims 3 to 5, characterized in that the first and the second cavity have a transparent wall (11, 13) opposite the membrane (1).
    [0007]
    7. Device according to claim 6, characterized in that the transparent wall of the first and / or second cavity comprises an optical filter (110) on its face opposite to the cavity. 15
    [0008]
    8. Device according to claim 6, characterized in that the transparent wall of the first and / or second cavity comprises a fixed optic (111, 130) on its face opposite to the respective cavity. 20
    [0009]
    9. Device according to claim 6, characterized in that the transparent wall of the first and / or second cavity comprises a variable-focus device.
    [0010]
    10. Device according to claim 9, characterized in that said wall (11) has a central opening (112) and in that said variable-focus device comprises: a deformable membrane (1 ') closing said opening (112) , a peripheral zone of the deformable membrane (1 ') being anchored to said wall (11), - at least one actuating device (5') of a region of the membrane situated between the peripheral anchoring zone and the central region of the membrane configured to flex said region of the membrane by applying an actuating electrical voltage to move a portion of the volume of the fluid toward the center or periphery of the cavity.
    [0011]
    11. Device according to one of claims 3 to 10, characterized in that the membrane (1) comprises a stiffening structure (14) comprising cells which delimit, in the central optical zone (1a) of said membrane, at least two deformable regions. 3037152 21
    [0012]
    12. Device according to claim 11, characterized in that the second transparent fluid (4) is arranged in the second cavity in the form of a plurality of elementary volumes each arranged opposite a respective cell. 5
    [0013]
    13. Device according to claim 11, characterized in that the second transparent fluid (4) is arranged in the form of a single continuous volume facing the cells.
    [0014]
    14. Device according to one of claims 3 to 10, characterized in that the second transparent fluid (2) is arranged on the wall of the second cavity opposite to the deformable membrane in the form of a plurality of elementary volumes.
    [0015]
    15. Device according to one of claims 1 to 14, wherein the actuating device (5) is piezoelectric. 15
    [0016]
    16. A method of manufacturing an optical device (100) with variable aperture according to one of claims 1 or 2, characterized in that it comprises the following steps: - provision of a variable-focus device comprising the deformable membrane (1), the actuating device (5) and the first transparent liquid (2) in the first cavity, - dispenses a determined volume of the opaque liquid (3) on the deformable membrane (1).
    [0017]
    17. A method of manufacturing an optical device (100) with variable aperture according to one of claims 3 to 14, characterized in that it comprises the following steps: - supply of the optical device with variable focus obtained by the method according to claim 16, - providing a second substrate (13) and dispensing the second transparent fluid (4) on said second substrate (13) in the form of at least one drop, - bonding the second substrate (13) on the optical device with variable focal length, so as to encapsulate the second transparent fluid (4) and the opaque liquid (3) between the second substrate (13) and the deformable membrane (1).
    类似技术:
    公开号 | 公开日 | 专利标题
    EP2184625B1|2013-08-21|Optical device with deformable membrane with improved activation
    EP2171503B1|2013-08-07|Optical device with means of actuating a compact deformable membrane
    EP2171504B1|2020-01-01|Optical device with membrane that can be deformed by electrostatic actuation
    EP2269109B1|2011-12-28|Improved membrane, especially for an optical device having a deformable membrane
    EP2478393B1|2017-06-14|Optical device having a piezoelectrically actuated deformable membrane
    EP2431770B1|2017-10-25|Device with membrane deformable by actuation with reduced response time
    EP2708923A1|2014-03-19|Optical device with piezoelectrically activated deformable membrane in the form of a continuous ring
    FR3029644A1|2016-06-10|AUTOFOCUS CAMERA AND VARIABLE FOCAL OPTICAL DEVICE INTENDED TO BE INTEGRATED WITH SUCH A CAMERA
    FR3015694A1|2015-06-26|OPTICAL DEVICE WITH FOCAL VARIATION
    WO2015091836A1|2015-06-25|Optical device for stabilising images
    FR2889633A1|2007-02-09|FLEXIBLE MEMBRANE ACTUATING DEVICE CONTROLLED BY ELECTROMOUILLAGE
    US10345574B2|2019-07-09|Optical device with variable aperture
    EP3123212B1|2020-06-24|Optical device with a deformable membrane
    EP3867688A1|2021-08-25|Microfluidic device designed to modify the phase of a wave front and optical system comprising such a device
    同族专利:
    公开号 | 公开日
    US10345574B2|2019-07-09|
    US9910263B2|2018-03-06|
    US20160357010A1|2016-12-08|
    AU2016270433B2|2018-11-01|
    FR3037152B1|2017-07-14|
    CN107690597B|2020-05-19|
    AU2016270433A1|2017-12-14|
    EP3304138B1|2020-09-09|
    EP3304138A1|2018-04-11|
    US20180188521A1|2018-07-05|
    WO2016197023A1|2016-12-08|
    CN107690597A|2018-02-13|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US3405623A|1965-12-07|1968-10-15|Polaroid Corp|Photographic exposure control apparatus|
    US6081388A|1996-03-26|2000-06-27|Mannesmann Ag|Opto-electronic imaging system for industrial applications|
    US20140192218A1|2013-01-07|2014-07-10|Samsung Electronics Co., Ltd.|Apparatus for adjusting aperture using microelectrofluidic method|
    US21470A|1858-09-07|harrison and jos |
    FR2919074B1|2007-07-19|2010-10-22|Commissariat Energie Atomique|OPTICAL DEVICE WITH MEMBRANE DEFORMABLE BY ELECTROSTATIC ACTUATION|
    FR2919073B1|2007-07-19|2010-10-15|Commissariat Energie Atomique|OPTICAL DEVICE WITH MEANS FOR ACTUATING A COMPACT DEFORMABLE MEMBRANE|
    EP2034338A1|2007-08-11|2009-03-11|ETH Zurich|Liquid Lens System|
    FR2930352B1|2008-04-21|2010-09-17|Commissariat Energie Atomique|IMPROVED MEMBRANE, IN PARTICULAR FOR A DEFORMABLE MEMBRANE OPTICAL DEVICE|
    FR2938349B1|2008-11-07|2011-04-15|Commissariat Energie Atomique|OPTICAL DEVICE WITH DEFORMABLE MEMBRANE WITH IMPROVED ACTUATION|
    FR2950153B1|2009-09-15|2011-12-23|Commissariat Energie Atomique|OPTICAL DEVICE WITH DEFORMABLE MEMBRANE WITH PIEZOELECTRIC ACTUATION|
    FR2950154B1|2009-09-15|2011-12-23|Commissariat Energie Atomique|OPTICAL DEVICE WITH DEFORMABLE MEMBRANE WITH PIEZOELECTRIC ACTUATION IN THE FORM OF A CONTINUOUS CROWN|
    EP2239600A1|2010-06-02|2010-10-13|Optotune AG|Adjustable optical lens|
    EP2823351A4|2012-03-07|2016-01-06|Univ Singapore|A mems iris diaphragm for an optical system and method for adjusting a size of an aperture thereof|
    JP6143274B2|2013-05-09|2017-06-07|国立大学法人 東京大学|Variable focus lens|
    KR20150054544A|2013-11-12|2015-05-20|삼성전자주식회사|Micro electric Liquid Device and Apparatus included the same|CN108346683B|2018-02-09|2021-01-05|上海天马有机发光显示技术有限公司|Light-emitting structure, display panel, display device and control method of display panel|
    CN109031484B|2018-09-25|2020-09-29|中国计量大学|Liquid lens of automatically controlled focusing|
    CN110596990A|2019-09-29|2019-12-20|Oppo广东移动通信有限公司|Aperture, camera and electronic device|
    法律状态:
    2016-05-16| PLFP| Fee payment|Year of fee payment: 2 |
    2016-12-09| PLSC| Search report ready|Effective date: 20161209 |
    2017-05-11| PLFP| Fee payment|Year of fee payment: 3 |
    2017-07-14| TP| Transmission of property|Owner name: WEBSTER CAPITAL LLC, US Effective date: 20170614 |
    2018-04-11| PLFP| Fee payment|Year of fee payment: 4 |
    2020-04-14| PLFP| Fee payment|Year of fee payment: 6 |
    2021-04-12| PLFP| Fee payment|Year of fee payment: 7 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1555035A|FR3037152B1|2015-06-03|2015-06-03|OPTICAL DEVICE WITH VARIABLE OPENING|FR1555035A| FR3037152B1|2015-06-03|2015-06-03|OPTICAL DEVICE WITH VARIABLE OPENING|
    US15/173,405| US9910263B2|2015-06-03|2016-06-03|Optical device with variable aperture|
    PCT/US2016/035863| WO2016197023A1|2015-06-03|2016-06-03|Optical device with variable aperture|
    AU2016270433A| AU2016270433B2|2015-06-03|2016-06-03|Optical device with variable aperture|
    CN201680031635.5A| CN107690597B|2015-06-03|2016-06-03|Optical device with variable aperture|
    EP16731428.5A| EP3304138B1|2015-06-03|2016-06-03|Optical device with variable aperture|
    US15/910,961| US10345574B2|2015-06-03|2018-03-02|Optical device with variable aperture|
    [返回顶部]