Method and system for reducing actuation force of adjustable optical element

Abstract

The present invention relates to a multi-phase actuation method for adjusting an optical element, wherein the optical element is composed of a plurality of actuators, wherein the method comprises the following steps: determining the end position of each actuator, actuating each actuator to the end position to adjust the optical element; in a first actuation stage, driving at least two or more actuators of the plurality of actuators to a first actuation position; in a second actuation stage, driving all actuators that have not yet reached their associated end positions to their associated end positions, wherein at least one of the two or more actuators reverses its driving direction to reach its associated end position, thereby causing the optical element to reach its adjustment state.

Description

[0001] manual

[0002] The invention relates to a multi-phase actuation method and a computer program, and an adjustable optical system.

[0003] Adjusting an optical element, such as a membrane-based liquid lens or other tunable optical element, such as a pixel shifter, based on bending, movement or deformation of at least one surface of the optical element is typically achieved by one or more actuators that adjust the optical element under the drive of some restoring force.

[0004] The required actuation force depends on the specific geometry, components and design of the optical element. The greater the restoring force, the greater the actuation force of the actuator. However, high actuation forces consume energy and force, so a relatively large actuator may be required.

[0005] Currently, our goal is to create energy-saving and small actuators that can generate high actuation forces. However, these goals have opposite effects on the actuator. Small actuators cannot generate large actuation forces, and vice versa.

[0006] Since many optical applications are battery-driven and the internal space of optical devices (such as mobile phones or glasses) is a valuable resource, it is necessary to provide compact optical components or systems that can combine all the above-mentioned characteristics, that is, optical components that require only a small internal space, energy-efficient optical components, and optical components or systems that can provide a high degree of optical adjustment (such as focus adjustment).

[0007] Therefore, the object of the present invention is to provide a method, a computer program and a system for multi-phase actuation of an adjustable optical element. The method of claim 1, the computer program of claim 15 and the system of claim 16 can achieve the above object.

[0008] Advantageous embodiments are described in the dependent claims.

[0009] According to a first aspect of the present invention, a multi-phase actuator method for adjusting an optical element comprises a plurality of actuators, the method comprising at least the following steps:

[0010] - determining an end position of each actuator, actuating each actuator to this end position in order to adjust the optical element to an adjusted state,

[0011] - in a first actuation phase, driving at least two or more of the plurality of actuators to a first actuation position, in particular causing the optical element to reach an intermediate state, in particular at the end of the first actuation phase the optical element is not in an adjusted state,

[0012] - In a second actuation phase, all actuators which have not yet reached the relevant end position are driven to the relevant end position, wherein at least one of the two or more actuators reverses its driving direction to reach the relevant end position, thereby bringing the optical element to an adjusted state.

[0013] The method allows adjusting an optical element using an actuator, in particular by actuating two or more actuators jointly to counteract said maximum restoring force, instead of reducing the maximum actuation force that a single actuator needs to generate to overcome the corresponding restoring force, by only the actuator experiencing said restoring force. Once this task is completed or substantially completed (at the end of the first actuation phase), at least one of the two or more actuators reverses its actuation direction in order to be driven to its associated end position.

[0014] Briefly, one embodiment of the invention involves a situation where a single actuator is subject to a considerable restoring force in its associated end position. The method provides that only the actuator needs to be driven to or towards said end position, while a plurality of actuators are driven to the end position, thereby jointly reducing the actuation force required to overcome the restoring force on the one actuator. After completing this task, several actuators are driven to the associated end position. In this way, the actuation force required for a single actuator is reduced, thereby reducing the maximum actuation force of the actuator, and thus smaller actuators can be used. Compared with a method of directly driving each actuator to its end position, this method may be more energy-efficient because the maximum actuation force is omitted.

[0015] This approach allows a given optical element to be actuated using an actuator designed to produce up to 20% less actuation force.

[0016] The actuator may be selected from one or more of the following group:

[0017] - Stepper motors,

[0018] - Direct drive motor,

[0019] - magnetic resistance motor,

[0020] - Electrostatic force motor,

[0021] - Voice coil actuator,

[0022] - piezoelectric actuators,

[0023] -Shape memory alloy (SMA) actuators.

[0024] In particular, the plurality of actuators may include 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14 or 16 actuators.

[0025] The actuation force of each actuator may be in the range of -5N to 5N, in particular -2.5N to 2.5N, more particularly -1N to 1N, even more particularly 0N to 1N.

[0026] The magnitude of the actuation force may be between 0.5N and 10N.

[0027] In particular, the actuator may be designed to generate a holding force greater than the actuation force. For example, the actuator may be designed to generate a holding force that is approximately 50% greater than the maximum actuation force.

[0028] According to another embodiment of the invention the plurality of actuators comprises no more than 12 actuators, in particular no more than 11, 10, 9, 8, 7, 6, 5, 4, 3 or 2 actuators.

[0029] According to another embodiment of the present invention, the plurality of actuators comprises at least 2 to 10 actuators, in particular at least 3, 4, 5, 6, 7, 8 or 9 actuators.

[0030] According to another embodiment of the present invention, at least some, in particular all, of the plurality of actuators are in contact with the optical element, or are in contact at different contact positions via one / multiple restoring force generating elements, and the actuators generate actuation forces at these contact positions. In addition, the actuation force applied at one contact position can be distributed to other contact positions via the optical element, so that the restoring force acting at one contact position can be offset and / or overcome by one or more actuators at different contact positions.

[0031] In this way, an energy-saving and labor-saving adjustment of the optical element is possible despite the fact that greater restoring forces may occur at one contact point.

[0032] In particular, the actuator is configured and arranged to actuate at least one adjustable portion of the optical element, wherein the actuator is in contact with the optical element at different contact areas.

[0033] The actuator may be in contact with one or more shaping elements configured to shape the optical surface of the optical element by applying a force to the optical element. In addition, the actuator may be in contact with a spring whose configuration and arrangement can adjust the optical properties of the optical element.

[0034] The end position of each actuator can be determined by reading the current position of the actuator and determining the end position so that the desired adjustment state of the optical element is achieved.

[0035] The end position may be determined by a processor, a control module, and / or a data processing system.

[0036] It should be noted that, in this specification, the concept of an actuator moving, driving, being driven, being moved or being actuated to a certain position refers to the actuation process, rather than the actuator itself being moved as a whole.

[0037] In particular, the interactor is configured to actuate back and forth in one direction only.

[0038] In particular, in a first actuation phase, two or more actuators are activated simultaneously or quasi-simultaneously with a short delay.

[0039] In particular, at least two or more actuators have an associated first position; that is, each of the two or more actuators has its own first position.

[0040] According to another embodiment of the invention, the first position is the same position for all actuators.

[0041] According to another embodiment of the invention, the first positions associated with at least some or all of the actuators are different from each other.

[0042] In particular, in each state the optical element generates a cumulative restoring force which is distributed between a plurality of actuators, in particular via contact locations and adjustable parts, such as shaping elements, wherein each actuator is subjected to a restoring force which corresponds to a portion of the cumulative restoring force.

[0043] In this way, the restoring force acting on the two or more actuators in the first position is distributed between the two or more actuators. This then makes it possible for each actuator to reach the first position with only a smaller actuation force.

[0044] Thus, the adjustable portion can transmit or generate a restoring force of the optical element, which can be distributed to different contact positions. The restoring force can also be a bending force or moment, originating from a bending module of a force generating element, such as a membrane. The bending force can be generated by bending or deforming the adjustable portion of the optical element.

[0045] It should be noted that after the first actuation phase, the optical element is not in a predetermined adjustment state, but in an intermediate state, whereas after the second actuation phase, in particular only after the second actuation phase, the optical element is in the adjustment state.

[0046] In particular, the method comprises the step of adjusting the optical element from a first adjustment state to a second adjustment state. The method starts with the first adjustment state, in which the end position is determined, and then a first actuation phase is performed, wherein after the first actuation phase the optical element is neither in the first adjustment state nor in the second adjustment state, but in an intermediate state. A second actuation phase is then performed, after which the optical element is in the second adjustment state.

[0047] In other words, the method provides that the determination of the end position is started in the first adjustment state and then the first and second actuation phases are carried out in order to reach the second adjustment state (only after the second actuation phase).

[0048] According to another embodiment of the invention, after the second actuation phase, the restoring force acting on at least one of the plurality of actuators that is closest to the first position or actuated in the first position is greater than the restoring force acting on at least another actuator in its associated end position.

[0049] This embodiment provides that in the first position or close to the first position, the restoring force may be greater than in a different position. Therefore, the method can provide actuation support for at least one actuator, thereby reducing the required actuation force because at least two actuators are driven to the first position. The first position may correspond to an end position of the actuator, and if the actuator is driven alone to the first / end position, a greater driving force is required.

[0050] According to another embodiment of the present invention, after the second actuation stage, the restoring force acting on at least one of the multiple actuators that is closest to the first position or actuated at the first position is higher than the restoring force acting on the respective end positions of at least two, three or more of the multiple actuators, in particular, after the second actuation stage, the restoring force acting on at least one of the multiple actuators that is closest to the first position or actuated at the first position is higher than the restoring force acting on 25%, 50% or 75% of all the actuators at their relevant end positions.

[0051] According to another embodiment of the invention, the restoring force acting on at least one of the plurality of actuators closest to the first position or actuated in the first position is greater than the restoring force acting on any other actuator in its associated end position.

[0052] This embodiment allows reducing the actuation force required for at least one actuator by pushing at least one actuator toward the first position, where the actuator will be actuated to a position closest to or proximate to the first position. Since the restoring force of the first position is greater than the restoring force of any other end position, this embodiment is particularly labor-saving and energy-saving.

[0053] According to another embodiment of the invention, the restoring force is a spring force.

[0054] According to another embodiment of the invention, the driving directions of the plurality of actuators extend along a first axis, in particular wherein the driving directions of the plurality of actuators are oriented along an optical axis of the optical element. In particular, the first direction corresponds to the optical axis of the optical element.

[0055] According to another embodiment of the present invention, the optical element is a liquid lens or an adjustable window element.

[0056] The liquid lens can in particular be a membrane-based liquid lens, i.e. a liquid lens with a liquid reservoir, wherein at least one optical surface of the liquid lens extends onto the liquid reservoir, wherein the shape of the membrane, in particular the curvature, can be adjusted by increasing or decreasing the pressure exerted by the liquid on the membrane. The pressure can be adjusted by driving an actuator.

[0057] The adjustable window element may be included in an adjustable beam deflection or beam steering device, such as a scanner, a pixel shifter of an imaging system, or a prismatic device.

[0058] By tilting or moving the window via an actuator, the optical properties of the optical element including the window can be adjusted.

[0059] According to another embodiment of the present invention, a plurality of actuators are arranged along a circumferential portion of a clear aperture of the optical element, and in particular, the contact positions are arranged along a circumferential portion of the clear aperture of the optical element.

[0060] According to another embodiment of the present invention, one or more shaping elements are arranged along the circumferential portion, wherein the actuator is configured to move or deform the one or more shaping elements to adjust the optical element.

[0061] The one or more shaping elements may be an annular element with a clear aperture in the center, or a shaping element that forms part of an annular or ring-like element. The one or more shaping elements may be circular, partially circular, elliptical, partially elliptical or polygonal. The one or more shaping elements may be configured to facilitate the transmission of the force of the actuator to the optical element and its adjustable portion. The sole intention of the one or more shaping elements is to facilitate permanent contact between the actuator and the optical element.

[0062] According to another embodiment of the present invention, in the adjusted state of the optical element, the profile of the one or more shaping elements changes along the first axis in the adjusted state of the optical element.

[0063] That is, the one or more shaping elements may be deformed by the actuator so that the one or more shaping elements present a profile with a varying height (ie, varying along the first axis) around the clear aperture of the optical element.

[0064] According to another embodiment of the invention, one or more actuators, in particular all actuators, exhibit an actuation force characteristic that is dependent on the load and / or the actuation position, in particular wherein the actuation force has a non-linear relationship with the load and / or the actuation position.

[0065] When the actuator does not exhibit linear or nearly linear actuation characteristics, but exhibits strong nonlinear characteristics, this embodiment can provide a corresponding solution. For example, a magnetic actuator may have a particularly weak actuation force in certain actuation states, and due to the nature of the magnetic force driving the actuator, this actuation force increases or decreases nonlinearly with the change of the actuation position.

[0066] Therefore, in the case where the optical element or the actuator has nonlinear actuation characteristics or nonlinear restoring force characteristics, this method can particularly meet the requirements of energy consumption and maximum actuation force.

[0067] According to another embodiment of the invention, the restoring force is non-Hookean, ie non-linear elastic.

[0068] This embodiment benefits in the same way from the method according to the invention as described in detail in the previous embodiment.

[0069] According to another embodiment of the present invention, all or at least a plurality of restoring forces acting on the actuator are coupled together through an optical element, in particular through an adjustable part, in particular through one or more shaping elements, so that the actuator cooperates to counteract the coupled restoring forces at least in the first actuation stage.

[0070] According to another embodiment of the invention, the holding force of each actuator is higher than the highest actuation force of each actuator.

[0071] The maximum achievable actuation force corresponds to the maximum designed actuation force of the actuator.

[0072] The holding force of the actuator may be generated in a different way than the actuating force, for example by means of a restraining element which locks the actuator in the actuated state.

[0073] In this way, the optical element can be adjusted to a state that cannot be reached by a conventional drive actuator, ie directly (ie omitting the first actuation stage) to an adjustment state without an actuator combined with the first actuation stage.

[0074] According to another embodiment of the invention, the holding force of the actuator is higher than the highest actuation force of the actuator.

[0075] According to another embodiment of the invention, the optical element is a membrane-based fluid or liquid lens, wherein in a first actuation stage, in particular only in the first actuation stage, the spherical power of the fluid lens is adjusted, wherein in a second actuation stage, in particular only in the second actuation stage, the cylindrical power of the fluid lens is adjusted.

[0076] According to a second aspect of the present invention, a computer program comprising computer program code is disclosed, wherein, when the computer program is executed on a data processing system (such as a computer or / and a controller), the computer program causes the data processing system to perform the method according to the first aspect, and in particular causes the data processing system to issue a control signal, which is configured to drive an actuator according to the method of the present invention.

[0077] According to a third aspect of the present invention, an adjustable optical system is disclosed, the system comprising at least the following components:

[0078] - optical elements with multiple actuators,

[0079] - base frame,

[0080] - at least one restoring force generating element,

[0081] - wherein the actuator is arranged to exert an actuation force between the base and the at least one restoring force generating element, thereby adjusting the optical element,

[0082] - A control module configured to drive the actuator according to the method of the invention.

[0083] It should be noted that embodiments, single, multiple or combined features and / or definitions provided and described in the context of a method or a computer program apply in the same or similar manner to the system and vice versa.

[0084] For example, the arrangement and configuration of the actuators may be specified in the method.

[0085] The term "adjusting an optical element" particularly refers to adjusting an optical property of an optical element by mechanical adjustment of the optical element by an actuator.

[0086] The pedestal essentially acts as a platform, providing a restoring force and a reaction force to the actuator, thereby adjusting the optical properties of the optical element when the actuator is actuated.

[0087] According to another embodiment of the present invention, the control module is connected to a data processing system for receiving and executing control signals from the control module, the data processing system storing a computer program according to the present invention.

[0088] The connection can be wireless. That is, the control module can be installed on the system, while the data processing system can be installed elsewhere.

[0089] The data processing system may be located in or consist of a control module.

[0090] A data processing system may be a computer, a distributed computing system, or a processor.

[0091] According to another embodiment of the invention, at least one restoring force generating element comprises a bellows and / or one or more elastically deformable films.

[0092] According to another embodiment of the present invention, a plurality of actuators are arranged along a circumferential portion of a clear aperture of the optical element.

[0093] According to another embodiment of the present invention, the system comprises one or more shaping elements arranged along a circumferential portion of the clear aperture, wherein the one or more shaping elements are in contact with the actuator.

[0094] As described hereinabove in relation to the first aspect of the invention, the shaping element may have a variety of shapes and geometries and may be used for a variety of purposes.

[0095] According to another embodiment of the present invention, the system comprises an elastically deformable membrane covering a fluid core, in particular a liquid core, wherein the system is configured to adjust the shape of the elastically deformable membrane using an actuator, in particular by moving and / or deforming one or more shaping elements, thereby adjusting the optical properties of the optical element.

[0096] The present embodiments enable particularly compact fluid core devices with high optical power and / or high membrane bending moments, which typically generate high restoring forces and therefore require high actuation forces.

[0097] According to another embodiment of the invention, one or more shaping elements are connected to the elastically deformable membrane at the peripheral portion of the clear aperture.

[0098] According to another embodiment of the present invention, the system includes a fluid lens, which is composed of an elastically deformable membrane, wherein the membrane is adjustable by an actuator to adjust optical properties, such as optical power of the fluid lens.

[0099] This design allows for particularly compact fluid lenses with high optical power and / or high bending moments.

[0100] According to another embodiment of the invention, the system comprises one or more restraining elements configured to generate a retaining force, wherein each restraining element is configured to lock the associated actuator in the end position or the first position and to maintain the retaining force in said position.

[0101] This embodiment can make the optical element structure compact and exhibit higher restoring force.

[0102] Figures and Examples

[0103] In particular, exemplary embodiments are described below in conjunction with the accompanying drawings. The drawings are attached to the claims and are accompanied by texts explaining the individual features of the illustrated embodiments and aspects of the invention. Each individual feature shown in the drawings and / or mentioned in the text of the drawings may be incorporated (also in a separate manner) into the claims relating to the device according to the invention.

[0104] Figure 1 A first embodiment of the method according to the invention is depicted;

[0105] Figure 2 A second embodiment of the method according to the invention is depicted;

[0106] Figure 3 A third embodiment of the method according to the invention is depicted;

[0107] Figure 4 A fourth embodiment of the method according to the invention is depicted;

[0108] Figure 5 A system according to the invention is shown.

[0109] exist Figure 1 In FIG. 1 , a first example of the method according to the invention is shown. Without being a special case, the optical element 1 comprises five actuators 11, 12, 13, 14, 15, which are connected to an adjustable part of the optical element 1, which in this example can be an elastically deformable membrane 3 of a liquid lens, at different contact positions c1, c2, c3, c4, c5. Figure 1 A essentially describes a situation in which the end position 21, 22, 23, 24, 25 of each actuator 11, 12, 13, 14, 15 has been determined. In addition, a first position 31 has also been determined. In this example, the first position 31 is the same for all actuators 11, 12, 13, 14, 15 (in terms of their position along the first axis z) and corresponds to the end position 23 of the actuator 13. Figure 1 The situation described in A may correspond to a first adjustment state of the optical element, wherein the goal is to adjust the optical element to adopt a second adjustment state.

[0110] In the present example, the restoring force at position 23 may be greatest compared to the remaining end positions 21 , 22 , 24 , 25 .

[0111] In this example, the method provides that, in a first actuation phase, two or more - in this example, all actuators are driven simultaneously to a first position 31. It should be noted that this state corresponds to an intermediate state of the optical element and does not correspond to the intended second adjustment state of the optical element. The restoring force at position 23 is distributed to adjacent actuators via the optical element 1 (e.g. a membrane corresponding to the adjustable part of the optical element). In turn, the driving force of the actuator can offset the restoring force at position 23, so that the actuator 13 generates a lower driving force, and in this case, the actuator 13 may be driven alone to its end position 23 without being supported by other actuators. Once reached (see Figure 1 B) First position 31, in the second actuation phase, the actuators 11, 12, 14, 15 which have not yet reached their end position will reverse their drive direction 41, 42, 44, 45 and drive towards their respective end position 21, 22, 24, 25, which can be supported by restoring forces pointing in the same direction, so that only a small drive force is required. The second adjustment state of the optical element 1 is as follows Figure 1 C. This second adjustment state may correspond to the "adjustment state" in the claims and part of the specification.

[0112] The restoring force acting on the actuator 13 may be greater than the maximum actuation force the actuator 13 is designed to generate. In order to fix the actuator 13 in its end position 23, the actuator 13 may exhibit a retaining force that is higher than its maximum producible actuation force.

[0113] exist Figure 2 In the Figure 1 For the sake of interchangeability, only Figure 1 and Figure 2 The differences between the illustrated embodiments are such that definitions and terms applicable to both embodiments will not be repeated, but may still apply Figure 2 The embodiment shown. Figure 3 and Figure 4 The same is true.

[0114] and Figure 1 The difference is that the first position 31 does not correspond to any end position of the actuator, but is only located close to the end position 23. Figure 2 In A, the driving directions of all actuators point to the first position, so the actuators are driven to the first position at the same time. Once the first position is reached (see Figure 2B), the driving directions of all actuators are reversed to drive the actuators towards their associated end positions. This embodiment is suitable for situations where the intermediate state (i.e. after the first actuation phase) is used to refer to and / or control the position of the actuators. This embodiment is also advantageous if the actuators show hysteresis in the control behavior or the generated actuation force has a strong non-linear relationship with the position. In these cases, it is necessary or advantageous to drive the actuators only in the direction of the restoring force during the second actuation phase, rather than in the opposite direction.

[0115] Figure 3 Another exemplary embodiment of the present invention is depicted. Figure 3 In A, the actuator is in a first adjustment state, and the end position of the actuator and the first position 31 have been determined.

[0116] In this example, although the resilience may be Figure 3 A points in the driving direction, but it can be imagined that the bending moment of the adjustable part of the optical element 1 depends on the radius of curvature, so for the actuator 14, the bending moment is particularly large because in the adjustment state ( Figure 3 C), the radius of curvature of the film 3 is smallest at the end position 24 .

[0117] In order to support the actuator 14, the actuators 13, 14 and 15 are driven into the first position in the first actuation phase, while the actuators 11 and 12 are driven directly into their respective end positions 21, 22. Figure 3 As shown in B, in the middle state of the optical element, the curvature radius of the adjustable part of the actuator 13, 14, 15 in the first position is relatively small.

[0118] In the second actuation phase, actuators 11 and 12 do not move but remain in their end positions, while actuators 13 and 15 reverse their driving direction. Actuator 14 continues to drive to its end position 24. The effect of the movement of actuators 13, 14 and 15 is that the radius of curvature and the restoring force generated by the bending of the adjustable portion are jointly generated and offset by actuators 13, 14 and 15, thereby reducing the time required to reach the end position 24. Figure 3 The single actuation force required to adjust the state of the optical element in C.

[0119] It should be noted that, during the second actuation phase, it may be advantageous to first drive the first actuator 14 to its end position 24 and then to drive the actuators 13 and 15 to their respective end positions 23 and 25 .

[0120] This example shows that, depending on the specific source of the restoring force and the specific characteristics of the optical element (here, the bending module), this approach can reduce the force requirements for actuation.

[0121] Figure 4An example is depicted in which two different first positions are determined. In a first actuation phase, the actuators 11, 12, 13 are determined to be driven to a first position 32, wherein the actuators 14, 15 are determined to be driven to another first position 31 (see Figure 4 A). This may be advantageous when restoring forces at different positions (due to bending moments and / or spring-like restoring forces) require that both actuators be supported by at least one other actuator. In particular, actuator 12 is supported by both actuators 11, 13, while actuator 15 is supported by only one other actuator 14.

[0122] from Figure 4 As can be seen in B, the three actuators 11, 13, 14 reverse their drive direction after the first actuation phase in order to reach their respective end positions. Figure 4 In C, an adjustment state of the optical element is depicted, in which all actuators have reached the relevant end position. It is conceivable that the restoring force at the position of actuator 12 may consist of a bending moment (due to the curvature of the adjustable part at the end position 22) and a spring force pointing in the first direction z, wherein the restoring force at the end position 25 of actuator 15 mainly consists of a spring force with a smaller bending moment, because the radius of curvature at the end position 25 is relatively high.

[0123] Figure 5 A system according to the invention is schematically depicted. Figure 5 A shows a cross-sectional top view of the system along the x-axis and y-axis, where Figure 5 B depicts a corresponding cross-sectional view of the system along the z-axis, which corresponds to the first direction z.

[0124] The optical system comprises a force generating element 3 in the form of an expandable membrane. The system also comprises a container consisting of a base frame 2 and a transparent bottom 7. Opposite the transparent bottom 7, the membrane seals the liquid in the container, so that the optical system comprises a fluid core 6.

[0125] The system 10 also includes an annular shaping element 5 that is deformable along the z-axis. The shaping element is arranged along the circumferential portion 201 of the membrane and allows the actuators 11-18 of the system to be connected to the membrane through the shaping element. The actuators are configured to push and / or pull the shaping element in the z-direction at the respective contact positions c1-c8, deforming the shaping element and thereby locally pushing or pulling the film towards or away from the transparent bottom. This allows the optical power of the system to be adjusted and to compensate and / or generate higher-order optical effects, such as cylinders, spheres, etc.

[0126] The system in this example includes eight actuators, but the number of actuators does not limit the present invention. The present invention may include systems with two, three, four, five, six, seven, eight, nine, ten, eleven, twelve or sixteen actuators.

[0127] The actuator is controlled by a control module 4, which can be connected to a data processing system (not shown) configured to perform the method of the present invention on the optical system. The control module may include a computer program or part of a computer program for performing the method and can provide power to the actuator so that the actuator moves accordingly.

[0128] Figure 5 The examples in the text essentially refer to a fluid lens, but other optical systems can also be configured to perform the method, including force generating elements, actuators, base frames, control modules, etc.

[0129] The fluid core may comprise an incompressible transparent liquid. Thus, when the actuator moves towards the transparent bottom, the expandable membrane will deform in the region of the clear aperture and form a lens surface. The radius of curvature depends on the amplitude of the actuation. The closer the actuator is to the bottom, the greater the restoring force in the opposite direction of the drive. Similarly, if the actuator is driven away from the bottom, the membrane will bend in the opposite direction and generate a restoring force in the other direction. In any case, for small radii of curvature, the method of the present invention can achieve such small radii without increasing the size / power of the actuator.

[0130] In order to determine the end position, in particular the first position(s), the control module may have a database comprising information about the specific optical system. With this information, the control module can determine the end position and the first position, for example by means of a look-up table, a formula evaluated from the first and second adjustment states or by means of preset states of the optical elements.

[0131] The simulation of the optical element yielded the following actuation forces. Table 1 shows the simulation of an optical element with eight actuators (11-18) with the end positions:

[0132] The second row of the table gives the end positions, while the restoring forces acting on each actuator at the end positions are given in the restoring force row. If each actuator is driven directly to the end position, the restoring force will be consistent with the actuation force required for the actuator. That is, in Table 1, if the method of the present invention is not implemented and each actuator is driven directly to its end position, then substantially the actuation force required for each actuator is provided. The maximum restoring force of actuator #5 is about -1N.

[0133] Table 1:

[0134]

[0135] In contrast, if the method of the present invention is performed on the same system shown in Table 2, in the first actuation stage, all actuators are driven to the first position, which corresponds to a travel of -2.4 mm, and is therefore the position to which actuator #5 needs to be driven. The restoring force acting on actuator #5 is only about -0.6 N, and the maximum restoring force acting on any one actuator is only -0.76 N, which means that actuator #5 only needs to generate a thrust of 0.6 N instead of 1 N to reach the end position.

[0136] In the second actuation stage, the remaining actuators #1, 2, 3, 4, 6, 7, 8 can be driven from the first position at -2.4 mm to their respective end positions, where the restoring force is anyway low. Although the restoring force on actuator #5 increases to -1 N again in the second actuation stage, this is only an insignificant issue because the holding force of the actuator is usually higher than the actuation force. In particular, the holding force of actuator #5 is greater than 1 N. If the system is configured to perform the method of the present invention, the method of the present invention can reduce the actuation force, thereby making the optical system more compact.

[0137] Table 2:

[0138]

[0139] The invention allows adjusting optical elements in an energy- and labor-saving manner.

[0140] Reference numerals

[0141] 1 Optical components

[0142] 2 Base frame

[0143] 3 Force generating element / membrane

[0144] 4 Control Module

[0145] 5 Shaping elements

[0146] 6 fluid core

[0147] 7 Transparent bottom

[0148] 10 Optical System

[0149] 11, 12, 13, 14, 15, 16, 17, 18 Actuator

[0150] 21, 22, 23, 24, 25 end positions

[0151] 31, 32 First place

[0152] 41, 42, 43, 44, 45 Drive direction

[0153] 51, 52, 53, 54, 55 Resilience

[0154] 200 Clear Aperture

[0155] 300 Circumference

[0156] c1, c2, c3, c4, c5 contact positions

[0157] z First axis

Claims

1. A multi-phase actuator method for adjusting an optical element (1), the optical element comprising a plurality of actuators (11, 12, 13, 14, 15, 16, 17, 18), wherein the method comprises the following steps: - determining an end position (21, 22, 23, 24, 25) of each actuator (11, 12, 13, 14, 15, 16), actuating each actuator (11, 12, 13, 14, 15, 16) to said end position in order to adjust the optical element (1), - in a first actuation phase, driving at least two or more actuators of the plurality of actuators (11, 12, 13, 14, 15, 16) to a first actuation position (31, 32), - In a second actuation phase, all actuators that have not yet reached the relevant end position (21, 22, 23, 24, 25) are driven to reach the relevant end position (21, 22, 23, 24, 25), wherein at least one of the two or more actuators reverses its driving direction (41, 42, 43, 44, 45) to reach the relevant end position, thereby bringing the optical element (1) into an adjusted state.

2. A method according to claim 1, wherein after the second actuation phase, the restoring force (51, 52, 53, 54, 55) acting on at least one actuator closest to the first position or actuated in the first position is higher than the restoring force acting on at least another actuator in its associated end position.

3. A method according to claim 2, wherein the restoring force acting on at least one actuator closest to the first position or actuated in the first position is greater than the restoring force acting on any other actuator in its associated end position.

4. A method according to any one of the preceding claims, wherein the restoring force is a spring force.

5. Method according to any of the preceding claims, wherein the driving direction of the plurality of actuators extends along the first axis (z).

6. The method according to any of the preceding claims, wherein the optical element (1) is a liquid lens or an adjustable window element.

7. The method according to any of the preceding claims, wherein a plurality of actuators are arranged along a circumferential portion (200) of a clear aperture (300) of the optical element (1).

8. The method according to claim 7, wherein one or more shaping elements (5) are arranged along the circumferential portion (200), and wherein the actuator is configured to move or deform the one or more shaping elements to adjust the optical element (1).

9. Method according to at least claims 5 and 8, wherein in an adjusted state of the optical element, a profile of the one or more shaping elements varies along the first axis in the adjusted state of the optical element.

10. A method according to any of the preceding claims, wherein one or more actuators, in particular all actuators, exhibit an actuation force characteristic that is dependent on the load and / or the actuation position, in particular wherein the actuation force has a non-linear relationship with the load and / or the actuation position.

11. A method according to any one of the preceding claims, wherein the restoring force is non-Hookean, ie non-linear elastic.

12. A method according to any of the preceding claims, wherein all restoring forces acting on the actuator are coupled via optical elements, in particular via one or more shaping elements, so that the actuator cooperates to counteract the coupled restoring forces at least in a first actuation phase.

13. A method according to any preceding claim, wherein the holding force of each actuator is higher than a highest achievable actuation force of each actuator.

14. A method according to any of the preceding claims, wherein the optical element (1) is a membrane-based fluid lens, and in a first actuation stage, in particular only in the first actuation stage, the spherical power of the fluid lens is adjusted, and in a second actuation stage, in particular only in the second actuation stage, the cylindrical power of the fluid lens is adjusted.

15. A computer program comprising computer program code, wherein when executed on a data processing system, the computer program causes the data processing system to perform a method according to any of the preceding claims, in particular causes the data processing system to issue a control signal, the control signal being configured to drive an actuator according to the method according to any of the preceding claims.

16. An adjustable optical system (10), comprising: - an optical element (1) with a plurality of actuators (11-18), - a base frame (2), - at least one restoring force generating element (3), - wherein the actuators (11-18) are arranged to exert an actuation force between the base frame (2) and the at least one restoring force generating element (3), - A control module (4) for driving an actuator (11-18) according to a method according to any of the preceding claims.

17. The system (10) according to claim 16, wherein the control module (4) is connected to a data processing system for receiving and executing control signals from the control module (4), the data processing system storing a computer program according to claim 15.

18. System according to claim 16 or 17, wherein at least one restoring force generating element (3) comprises a bellows and / or one or more elastically deformable membranes.

19. The system according to any one of claims 16 to 18, wherein the plurality of actuators are arranged along a circumferential portion (200) of a clear aperture (300) of the optical element (1).

20. The system according to claim 19, wherein the system comprises one or more shaping elements (5) arranged along a circumferential portion (200) of the clear aperture (300), wherein the one or more shaping elements are in contact with the actuator.

21. A system according to any one of claims 16 to 20, wherein the system (10) comprises an elastically deformable film covering a fluid core (6), in particular a liquid core, wherein the system is configured to adjust the shape of the elastically deformable film (3) by means of an actuator, in particular by moving and / or deforming one or more shaping elements, thereby adjusting the optical properties of the optical element (1).

22. System according to claims 20 and 21, wherein one or more shaping elements (5) are connected to the elastically deformable membrane (3) at a circumferential portion of the clear aperture.

23. A system according to any one of claims 21 or 22, wherein the system comprises a fluid lens, the fluid lens comprising an elastically deformable film, wherein the film can be adjusted by an actuator to adjust optical properties, such as the optical focal length of the fluid lens.

24. A system according to any one of claims 16 to 23, wherein the system comprises one or more restraining elements configured to generate a retaining force, wherein each restraining element is configured to lock the associated actuator in an end position or a first position and maintain the retaining force in said position.

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