Control method for micro-electromechanical systems

Abstract

The present invention relates to a method for controlling a microelectromechanical system by means of an electrical control signal alternating between a maximum voltage value (Vmax) and a minimum voltage value (Vmin), wherein during the transition from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), the value of the voltage of the electrical control signal decreases monotonically from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), the signal being: a first slope between a maximum voltage value (Vmax) and a first voltage threshold (Vend); a second slope between the first voltage threshold (Vend) and the second voltage threshold (Vstart), the second slope having an absolute value less than the first slope; and a third slope between a second voltage threshold (Vstart) and a minimum voltage value (Vmin), the third slope being higher in absolute value than the second slope.

Description

Technical Field

[0001] The present invention relates to the field of micro-electro-mechanical systems.

Background Art

[0002] Micro-electro-mechanical systems (or MEMS) are small systems manufactured by etching semiconductor materials. These microsystems comprise mechanical components having micrometer dimensions and use electricity as an energy source for operation.

[0003] French Patent Application Publication No. 2874907 describes, for example, a driving device formed by etching a chip of a semiconductor material such as silicon. The driving device comprises an actuator constituted by driving teeth that can sequentially engage with a gear, a first element module capable of moving the driving teeth along a first axis (radial axis), and a second element module capable of moving the teeth relative to the gear along a second axis (tangential axis). The first element module and the second element module are electrostatic modules having a structure composed of intermeshing combs.

[0004] The first element module and the second element module are controlled by phase-shifted alternating addressing signals so as to move the driving teeth in a periodic motion having a hysteresis trajectory. During this periodic movement, the driving teeth alternately repeat a driving phase and a disengagement phase. In each cycle, the driving teeth engage with a tooth of the gear and rotate the gear by one step. The cycle is repeated such that the driving teeth engage with successive teeth of the gear, thereby driving the gear in a stepwise rotational motion.

[0005] During the driving phase, the driving teeth move in a first direction as a result of the electrostatic force generated by the intermeshing combs. On the other hand, during the disengagement phase, the driving teeth move in a second direction opposite to the first direction as a result of the elastic return force generated by the suspension of the intermeshing combs.

[0006] This type of drive device can be used to drive the gears of a clock mechanism in place of a conventional clock motor, and generally has the advantage of reducing the number of mechanical parts required to rotate the gears.

[0007] One problem encountered with this type of drive device is that, in each basic motion (i.e., in the first or second direction), the actuator may experience rebound or vibration. Rebound generally occurs at the end of the stroke when the moving part strikes one of the fixed parts of the module. Vibration also occurs at the end of the stroke when the moving part returns to its equilibrium position as a result of an elastic restoring force.

[0008] However, these rebounds and / or these residual vibrations are detrimental to the proper operation of the actuator for several reasons.

[0009] On the one hand, the appearance of these bounces and / or vibrations causes an increase in the duration of stabilization of the basic motion and limits the frequency at which the drive device can be controlled.

[0010] On the other hand, rebound causes repeated impacts between mechanical parts, degrading the contact surfaces between these parts and consequently reducing the lifespan of the micro-electromechanical system. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] French Patent Application Publication No. 2874907 [Overview of the project] [Problems that the invention aims to solve]

[0012] One objective of the present invention is to propose a solution for limiting residual vibration and / or rebound phenomena in micro-electromechanical systems. [Means for solving the problem]

[0013] This problem is solved within the scope of the present invention by relating to a method for controlling a micro-electromechanical system, the micro-electromechanical system comprising a support and an actuator, the actuator being A fixing part that is fixed and attached to the support, A movable part that is movably attached to the support, It includes a suspension that connects the movable parts to a support.

[0014] The control method includes the step of applying an electrical control signal between a fixed part and a movable part, wherein the control signal alternates between a maximum voltage value and a minimum voltage value so that the movable part moves relative to the fixed part. In the first direction, as the electrical control signal transitions from a minimum voltage value to a maximum voltage value, the electrostatic force generated between the movable part and the fixed part causes the movement of the movable part relative to the fixed part to result in elastic deformation of the suspension. In a second direction opposite to the first, when the electrical control signal transitions from a maximum voltage value to a minimum voltage value as a result of the elastic restorative force generated by the elastic deformation of the suspension, the elastic restorative force counteracts the electrostatic force.

[0015] During the transition from the maximum voltage value to the minimum voltage value, the voltage value of the electrical control signal decreases monotonically from the maximum voltage value to the minimum voltage value, and during that time, The first mean slope between the maximum voltage value and the first threshold voltage value, A second mean slope between the first threshold voltage value and the second threshold voltage value, having an absolute value smaller than the first mean slope, It has a third mean slope between the second threshold voltage value and the minimum voltage value, the third mean slope having a larger absolute value than the second mean slope.

[0016] When the electric control signal transitions from the first threshold voltage value to the second threshold voltage value, the movable part moves in a second direction opposite to the first direction relative to the fixed part as a result of the elastic restoring force generated by the elastically deformed suspension.

[0017] Therefore, the specific shape of the electric control signal, more precisely the presence of the second average slope, enables damping of the movement of the movable part relative to the fixed part when the movable part moves in the second direction. This has the effect of damping bounce and / or residual vibration of the movable part relative to the fixed part.

[0018] At the same time, the presence of the first average slope and the third average slope, which have larger absolute values than the second average slope, can minimize the time required for the electric control signal to transition from the maximum voltage value to the minimum voltage value. Therefore, the frequency at which the driving device can be controlled remains high.

[0019] Therefore, the proposed method makes it possible to limit the phenomena of vibration and / or bounce while enabling control of the actuator at high frequencies.

[0020] This method can also have the following features.

[0021] In one possible embodiment of the method, during the transition from the minimum voltage value to the maximum voltage value, the voltage value of the electric control signal increases monotonically from the minimum voltage value to the maximum voltage value, during which a fourth average slope between the minimum voltage value and the second threshold voltage value, a fifth average slope between the second threshold voltage value and the first threshold voltage value, the absolute value of which is smaller than that of the fourth average slope, and a sixth average slope between the first threshold voltage value and the maximum voltage value, the absolute value of which is larger than that of the fifth average slope, are sequentially provided.

[0022] When an electrical control signal transitions from a second threshold voltage value to a first threshold voltage value, the movable part moves in a first direction relative to the fixed part as a result of an electrostatic force generated between the movable part and the fixed part.

[0023] In one possible embodiment of the method, the actuator further comprises a frame fixedly attached to a support, and the first threshold voltage value is selected such that when the electrical control signal takes a voltage value greater than the first threshold voltage value, the electrostatic force generated between the movable part and the fixed part is sufficient to hold the movable part in abutment against the frame, and when the electrical control signal takes a voltage value less than the first threshold voltage value, the electrostatic force generated between the movable part and the fixed part is insufficient to hold the movable part in abutment against the frame.

[0024] In one possible embodiment of the method, the second threshold voltage value is selected such that when the electrical control signal takes a voltage value less than the second threshold voltage value, the electrostatic force generated between the movable part and the fixed part is insufficient to move the movable part relative to the fixed part, and when the electrical control signal takes a voltage value greater than the second threshold voltage value, the electrostatic force generated between the movable part and the fixed part is sufficient to move the movable part relative to the fixed part.

[0025] In one possible embodiment of the method, the electrical control signal applied between the fixed part and the movable part is periodic so as to cause the movable part to alternately move in the first direction as a result of the electrostatic force and in the second direction as a result of an elastic return force, In one possible embodiment of the method, a second average slope is selected such that the electrical control signal transitions from the first threshold voltage value to the second threshold voltage value within a time substantially equal to one natural free vibration period of the movable part relative to the fixed part.

[0026] In one possible embodiment of this method, the second mean gradient is selected such that the electrical control signal transitions from a first threshold voltage value to a second threshold voltage value within a time period that falls within a range of 0.7 to 1.3 times one natural free vibration period of the movable part relative to the fixed part.

[0027] The present invention also relates to an electrical control signal for controlling a micro-electromechanical system, wherein the electrical control signal alternates between a maximum voltage value and a minimum voltage value, and during the transition from the maximum voltage value to the minimum voltage value, the voltage value of the electrical control signal monotonically decreases from the maximum voltage value to the minimum voltage value, during which time, The first mean slope between the maximum voltage value and the first threshold voltage value, A second mean slope between the first threshold voltage value and the second threshold voltage value, having an absolute value smaller than the first mean slope, It has a third mean slope between the second threshold voltage value and the minimum voltage value, the third mean slope having a larger absolute value than the second mean slope.

[0028] Electrical control signals may also have the following characteristics:

[0029] In one possible embodiment of an electrical control signal, during the transition from a minimum voltage value to a maximum voltage value, the voltage value of the electrical control signal increases monotonically from the minimum voltage value to the maximum voltage value, during which time, The fourth mean slope between the minimum voltage value and the second threshold voltage value, A fifth mean slope between the second threshold voltage value and the first threshold voltage value, which has an absolute value smaller than the fourth mean slope, It has a sixth mean slope, which has a larger absolute value than the fifth mean slope, between the first threshold voltage value and the maximum voltage value.

[0030] In one possible embodiment of the electrical control signal, the electrical control signal is periodic.

[0031] The present invention also relates to a control circuit for controlling a micro-electromechanical system, wherein the control circuit is configured to generate electrical control signals as defined above.

[0032] The device may also have the following characteristics:

[0033] In one possible embodiment of the device, the device is A micro-electromechanical system comprising a support and an actuator, wherein the actuator comprises a fixed portion fixedly attached to the support, a movable portion movably attached to the support, and a suspension connecting the movable portion to the support, The previously defined control circuit comprises a control circuit that is connectable to an actuator for applying an electrical control signal between a fixed part and a movable part, wherein as an electrostatic force is generated between the movable part and the fixed part when the electrical control signal transitions from a minimum voltage value to a maximum voltage value, the movable part moves in a first direction relative to the fixed part, the movement of the movable part relative to the fixed part causes elastic deformation of the suspension, and as an elastic restoring force generated by the elastically deformed suspension resists the electrostatic force when the electrical control signal transitions from a first threshold voltage value to a second threshold voltage value, the movable part moves in a second direction opposite to the first direction relative to the fixed part.

[0034] In one possible embodiment of the device, the movable part moves in a first direction relative to the fixed part as a result of an electrostatic force generated between the movable part and the fixed part when the electrical control signal transitions from a second threshold voltage value to a first threshold voltage value.

[0035] In one possible embodiment of the device, the actuator also comprises a frame fixedly mounted to a support, wherein a first threshold voltage value is selected such that, when the electrical control signal takes a voltage value greater than the first threshold voltage value, the electrostatic force generated between the movable part and the stationary part is sufficient to hold the movable part in contact with the frame, and when the electrical control signal takes a voltage value less than the first threshold voltage value, the electrostatic force generated between the movable part and the stationary part is insufficient to hold the movable part in contact with the frame.

[0036] In one possible embodiment of the device, the second threshold voltage value is selected such that, when the electrical control signal takes a voltage value less than the second threshold voltage value, the electrostatic force generated between the movable part and the stationary part is insufficient to move the movable part relative to the stationary part, and when the electrical control signal takes a voltage value greater than the second threshold voltage value, the electrostatic force generated between the movable part and the stationary part is sufficient to move the movable part relative to the stationary part.

[0037] In one possible embodiment of the device, the second mean gradient is selected such that the electrical control signal transitions from a first threshold voltage value to a second threshold voltage value in a time substantially equal to one natural free vibration period of the moving part relative to the stationary part.

[0038] In one possible embodiment of the device, the second mean gradient is selected such that the electrical control signal transitions from a first threshold voltage value to a second threshold voltage value within a time period that falls within a range of 0.7 to 1.3 times one natural free vibration period of the movable part relative to the fixed part.

[0039] In one possible embodiment of the device, the micro-electromechanical system comprises a gear that can be rotationally driven by an actuator relative to a support around a rotation axis.

[0040] Other features and advantages will also become apparent from the following description, which is purely illustrative and not limiting, and should be read with reference to the attached drawings. [Brief explanation of the drawing]

[0041] [Figure 1] This is a schematic side view illustrating a micro-electromechanical system according to one possible embodiment of the present invention. [Figure 2] This is a schematic top view illustrating a micro-electromechanical system. [Figure 3]Figure 2 is a detailed diagram of the micro-electromechanical system, showing the drive module, stopper, and part of the latch mechanism for positioning the stopper. [Figure 4] Figure 2 is a detailed view of the micro-electromechanical system, showing a portion of the disengagement module. [Figure 5] Figure 2 is a detailed diagram of the micro-electromechanical system, showing a portion of the indexing module. [Figure 6] Figure 2 is a detailed diagram of the micro-electromechanical system, showing the drive teeth and indexing teeth. [Figure 7] This diagram schematically shows the steps involved in initializing the latch mechanism. [Figure 8] This diagram schematically shows the steps involved in initializing the latch mechanism. [Figure 9] This diagram schematically shows the steps involved in initializing the latch mechanism. [Figure 10] This diagram schematically shows the steps involved in initializing the latch mechanism. [Figure 11] This diagram schematically shows the drive module before the latch mechanism is initialized. [Figure 12] This diagram schematically shows the drive module after the latch mechanism has been initialized. [Figure 13] This diagram schematically shows the strength of different forces acting on the drive teeth when the movable drive part moves in a first direction relative to the fixed drive part, for the first flexible beam width. [Figure 14] This diagram schematically shows the strength of the elastic restoring force acting on the drive teeth when the movable drive part moves relative to the fixed drive part in a second direction opposite to the first direction relative to the first flexible beam width. [Figure 15] This diagram schematically shows the strengths of different forces acting on the drive teeth when the movable drive part moves in a first direction relative to the fixed drive part with a second flexible beam width. [Figure 16] This diagram schematically shows the strength of the elastic restoring force acting on the drive teeth when the movable drive part moves relative to the fixed drive part in a second direction opposite to the first direction, with respect to the second flexible beam width. [Figure 17] This is a detailed diagram of the interlocking finger shapes of a comb. [Figure 18] This diagram schematically shows the first periodic motion of the drive teeth that enables the gear to be driven in a first rotational direction. [Figure 19] This diagram schematically illustrates the second periodic motion of the drive teeth, which enables the gear to be driven in a second rotational direction opposite to the first rotational direction. [Figure 20] This is a schematic diagram of a micro-electromechanical system according to one possible embodiment of the present invention before the initialization of the latch mechanism. [Figure 21] This is a schematic diagram of a micro-electromechanical system according to one possible embodiment of the present invention after the initialization of the latch mechanism. [Figure 22] This diagram schematically shows the electrical control signals for the drive module, the engagement module, and the indexing module, with each electrical control signal having a square wave shape. [Figure 23] This diagram provides a more detailed view of the electrical control signals for the drive module, the engagement module, and the indexing module over a period of time. [Figure 24] This figure schematically shows the movement of the drive module, engagement module, and indexing module obtained when the actuator is controlled by the electrical control signals shown in Figures 22 and 23. [Figure 25] This diagram schematically shows the movement of the drive module as a function of the voltage value of the drive module's electrical control signal. [Figure 26] This diagram schematically shows the movement of the engagement module as a function of the voltage value of the electrical control signal for the engagement module. [Figure 27] This diagram schematically shows the behavior of the indexing module as a function of the voltage value of the electrical control signal of the indexing module. [Figure 28] This figure schematically shows the electrical control signals for the drive module, the engagement module, and the indexing module according to one possible embodiment of the present invention. [Figure 29]This figure schematically shows the movement of the drive module when the actuator is controlled by the electrical control signal shown in Figure 14. [Figure 30] This figure schematically shows the movement of the engagement module when the actuator is controlled by the electrical control signal shown in Figure 14. [Figure 31] This figure schematically shows the electrical control signals for the drive module and the engagement module according to another possible embodiment of the present invention. [Figure 32] This diagram schematically shows a control circuit for controlling a micro-electromechanical system. [Figure 33] This figure schematically shows the attenuation circuit that forms part of the control circuit in Figure 32. [Modes for carrying out the invention]

[0042] The micro-electromechanical systems 10 shown in Figures 1 to 6 are obtained, for example, by an etching method within a semiconductor material substrate 1 such as silicon.

[0043] The substrate 1 used is, for example, a "silicon-on-insulator" (SOI) type. This substrate 1 includes a thick underlayer of silicon (first layer 2), an intermediate layer of silicon oxide (second layer 3), and an upper layer of silicon having a thinner thickness than the underlayer (third layer 4). The upper layer 4 of substrate 1 is etched to form a set of mechanical parts 5, while the underlayer 2 of substrate 1 is not etched and constitutes a support 6 for the mechanical parts 5. Part of the intermediate layer of silicon oxide 3 acts as a sacrificial layer and is removed to allow the movable mechanical parts to be removed from the support 6, while another part of the sacrificial layer remains and allows the mechanical parts to be attached to the support 6. Furthermore, the remaining part of the sacrificial layer acts as an electrical insulator between the mechanical parts 5 and the support 6, and therefore between different mechanical parts 5.

[0044] Therefore, the micro-electromechanical system 10 shown in Figures 1 to 6 comprises a support 6 and a mechanical part 5 having minute dimensions. The mechanical part 5 is positioned above the surface of the support 6.

[0045] More precisely, in the examples shown in Figures 1 to 6, the micro-electromechanical system 10 comprises an actuator 11 and a wheel 12. The actuator 11 is formed in the upper layer 4 of the substrate 1. The wheel 12 may also be formed in the upper layer 4 of the substrate 1, or it may be a separately formed insert.

[0046] The actuator 11 is configured to drive the wheel 12 to rotate relative to the support 6 around the axis of rotation.

[0047] The actuator 11 shown in Figures 2 to 4 comprises a frame 100 and three element modules 200, 300, and 400.

[0048] The frame 100 is fixed to the support 6.

[0049] The three basic modules include a drive module 200, an engagement module 300, and an indexing module 400.

[0050] The wheel 12 is a gear; that is, it has a series of teeth on its outer circumference. Each tooth extends along the radial axis with respect to the wheel's axis of rotation. The gear 12 can have a diameter that falls between 2,000 and 10,000 μm. The gear 12 can have, for example, teeth between 200 and 1,000.

[0051] The drive module 200 includes a fixed drive section 210 and a movable drive section 220.

[0052] The fixed drive unit 210 is fixedly attached to the support 6. The fixed drive unit 210 comprises a first carrier 214 and a plurality of fixed combs 211 extending perpendicularly from the first carrier 214. Each fixed comb 211 comprises a shank 212 and fingers 213 extending perpendicularly from the shank 212.

[0053] The movable drive unit 220 comprises a second carrier 224 and a plurality of movable combs 221 extending perpendicularly from the second carrier 224. Each movable comb 221 comprises a shank 222 and fingers 223 extending perpendicularly from the shank 222.

[0054] The actuator 11 also includes a first suspension 230 that connects the movable drive portion 220 to the frame 100. The first suspension 230 includes two flexible beams 231 that extend parallel to the shank 222 of the movable comb 221. The flexible beams 231 connect the second carrier 224 to the frame 100.

[0055] The movable combs 221 are arranged alternately between the fixed combs 211. That is, the movable combs 221 are arranged alternately with the fixed combs 211. Furthermore, the movable combs 221 and fixed combs 211 are arranged in pairs, with each pair comprising a fixed comb 211 and its associated movable comb 221. More precisely, the fingers 213 of each fixed comb 211 in a pair have their free ends extending toward the fingers 223 of the associated movable comb 221 in the same pair. Similarly, the fingers 223 of a pair of movable combs 221 have their free ends extending toward the fingers 213 of the fixed comb 211 in the same pair. Furthermore, the fingers 213 of the fixed combs 211 and the fingers 223 of the movable combs 221 extend parallel to the tangential axis.

[0056] The axis perpendicular to the radius of the wheel 12 that passes through the position where the actuator 11 interacts with the wheel 12 is called the "tangential axis".

[0057] The drive module 200 also includes a contact pad 215 formed on the fixed drive portion 210. The contact pad 215 can be connected to a control circuit for applying electrical control signals to the fixed drive portion 210. The contact pad 215 can be formed by depositing a metal layer on the fixed drive portion 210.

[0058] The actuator 11 also includes one or more contact pads 115 formed on the frame 100. The contact pads 115 can be connected to ground. The contact pads 115 can be formed by depositing one or more metal layers on the frame 100.

[0059] The actuator 11 also includes a drive tooth 116 and a drive beam 117 that connects the drive tooth 116 to the movable drive portion 220 of the drive module 200.

[0060] The drive teeth 116 engage with the teeth 121 of the gear 12 to rotate the gear 12. The drive beam 117 extends along the tangential axis to the gear 12.

[0061] By applying a non-zero voltage between the fixed drive part 210 and the movable drive part 220 via the electrical contact pads 115 and 215, an electrostatic force is generated that attracts the movable comb 221 toward the fixed comb 211. More precisely, each pair of movable combs 221 is attracted toward the same pair of fixed combs 211. Due to the electrostatic force between the combs 211 and 221, the movable drive part 220 moves in a first direction (arrow A) parallel to the tangential axis with respect to the fixed drive part 210.

[0062] As the movable drive portion 220 moves in a first direction relative to the fixed drive portion 210, the first suspension 230 undergoes elastic deformation. This elastic deformation of the suspension 230 includes bending of the flexible beam 231 that connects the movable drive portion 220 to the frame 100. This elastic deformation generates an elastic restorative force in the first suspension 230 that attempts to counteract the electrostatic force. This restorative force increases with the amplitude of the elastic deformation experienced by the first suspension 230.

[0063] When the tension on the fixed drive portion 210 and the movable drive portion 220 decreases or becomes zero, the electrostatic force becomes less than or zero than the elastic restorative force. Due to the elastic restorative force generated by the first suspension 230, the movable drive portion 220 moves in a second direction (arrow B) opposite to the first direction parallel to the tangential axis with respect to the fixed drive portion 210. More precisely, each of the pair of movable combs 221 moves away from the same pair of fixed combs 211.

[0064] When the drive tooth 116 is connected to the movable drive part 220 via the drive beam 117, the drive module 200 can move the drive tooth 116 continuously in a first direction (arrow A) and then in a second direction (arrow B) parallel to the tangential axis.

[0065] The engagement module 300 comprises a fixed engagement portion 310 and a movable engagement portion 320.

[0066] The fixed engagement portion 310 is fixedly attached to the support 6. The fixed engagement portion 310 comprises a third carrier 314 and a plurality of fixed combs 311 extending perpendicularly from the third carrier 314. Each fixed comb 311 comprises a shank 312 and fingers 313 extending perpendicularly from the shank 312.

[0067] The movable engagement portion 320 comprises a fourth carrier 324 and a plurality of movable combs 321 extending perpendicularly from the fourth carrier 324. Each movable comb 321 comprises a shank 322 and fingers 323 extending perpendicularly from the shank 322.

[0068] The fixed comb 311 and movable comb 321 of the engagement module 300 are oriented perpendicularly to the fixed comb 211 and movable comb 221 of the engagement module 200.

[0069] The actuator 11 also includes a second suspension 330 that connects the movable engagement portion 320 to the frame 100. The second suspension 330 includes two flexible beams 331 that extend parallel to the shank 322 of the movable comb 321. The flexible beams 331 connect the fourth carrier 324 to the frame 100.

[0070] The movable combs 321 are arranged alternately between the fixed combs 311. Furthermore, the movable combs 321 and fixed combs 311 are arranged in pairs, with each pair comprising a fixed comb 311 and its associated movable comb 321. More precisely, the fingers 313 of each fixed comb 311 in a pair extend with their free ends directed toward the fingers 323 of the associated movable comb 321. Similarly, the fingers 323 of the movable comb 321 extend with their free ends directed toward the fingers 313 of the fixed comb 311. In addition, the fingers 313 of the fixed combs 311 and the fingers 323 of the movable comb 321 extend parallel to the radial axis.

[0071] The axis parallel to the radius of the wheel 12 that passes through the position where the actuator 11 interacts with the wheel 12 is called the "radial axis".

[0072] The engagement module 300 also includes a contact pad 315 formed on the fixed engagement portion 310. The contact pad 315 can be connected to a potential source for applying an electrical control signal to the fixed engagement portion 310.

[0073] The actuator 11 also includes an engagement beam 118 that connects the drive teeth 116 to the movable engagement portion 320 of the engagement module 300.

[0074] The engagement beam 118 extends along the radial axis relative to the gear 12.

[0075] When a non-zero voltage is applied between the fixed engagement portion 310 and the movable engagement portion 320 via the electrical contact pads 115 and 315, an electrostatic force is generated that pulls the movable comb 321 toward the fixed comb 311. More precisely, each pair of movable combs 321 is pulled toward the same pair of fixed combs 311. Due to the generated electrostatic force, the movable engagement portion 320 moves in a third direction (arrow C) parallel to the radial axis relative to the fixed engagement portion 310.

[0076] Movement of the movable engagement portion 320 relative to the fixed engagement portion 310 in a third direction causes elastic deformation of the second suspension 330. This elastic deformation of the suspension 330 includes bending of the flexible beam 331 that connects the movable engagement portion 320 to the frame 100. This elastic deformation causes the second suspension 330 to generate an elastic restorative force that attempts to counteract the electrostatic force. This restorative force increases with the amplitude of the elastic deformation.

[0077] When the tension between the fixed engagement portion 310 and the movable engagement portion 320 decreases or becomes zero, the electrostatic force becomes less than or zero than the elastic restorative force. Due to the elastic restorative force generated by the second suspension 330, the movable engagement portion 320 moves in a fourth direction (arrow D) opposite to the third direction parallel to the radial axis relative to the fixed engagement portion 310.

[0078] Therefore, when the drive tooth 116 is connected to the movable engagement portion 320 via the engagement beam 118, the drive tooth 116 can be moved continuously in a third direction (arrow C) and a fourth direction (arrow D) parallel to the radial axis by the engagement module 300.

[0079] Each of the drive beam 117 and the engagement beam 118 has sufficient flexibility to transmit the tangential motion generated by the drive module 200 and the radial motion generated by the engagement module 300 to the drive teeth 116, respectively, while allowing for the separation of these two motions. Thus, the two motions (tangential motion and radial motion) can be controlled independently of each other.

[0080] The indexing module 400 includes a fixed indexing section 410 and a movable indexing section 420.

[0081] The fixed indexing section 410 is fixedly mounted on a support. The fixed indexing section 410 comprises a fifth carrier 414 and a plurality of fixed combs 411 extending perpendicularly from the fifth carrier 414. Each fixed comb 411 comprises a shank 412 and fingers 413 extending perpendicularly from the shank 412.

[0082] The movable indexing section 420 comprises a sixth carrier 424 and a plurality of movable combs 421 extending perpendicularly from the sixth carrier 424. Each movable comb 421 comprises a shank 422 and fingers 423 extending perpendicularly from the shank 422.

[0083] The actuator 11 also includes a third suspension 430 that connects the movable indexing portion 420 to the frame 100. The third suspension 430 includes two flexible beams 431 that extend parallel to the shank 422 of the comb 421. The flexible beams 431 connect the transverse beam 424 to the frame 100.

[0084] The movable combs 421 are arranged alternately between the fixed combs 411. Furthermore, the movable combs 421 and fixed combs 411 are arranged in pairs, with each pair comprising a fixed comb 411 and its associated movable comb 421. More precisely, the fingers 413 of each fixed comb 411 in a pair extend with their free ends directed toward the fingers 423 of the associated movable comb 421. Similarly, the fingers 423 of the movable comb 421 extend with their free ends directed toward the fingers 413 of the fixed comb 411. In addition, the fingers 413 of the fixed comb 411 and the fingers 423 of the movable comb 421 extend parallel to the radial axis.

[0085] The actuator 11 also includes an indexing tooth 120. In the example shown in Figure 3, the indexing tooth 120 comprises two projections 126 and a recess 127 provided between the two projections 126. When the indexing tooth 120 engages with the teeth 121 of the gear 12, the recess 127 receives the teeth 121 of the gear 12 into the recess 127, which has the effect of preventing the rotation of the wheel 12.

[0086] The actuator 11 also includes an indexing beam 128 that connects the indexing teeth 120 to the movable indexing portion 420 of the indexing module 400.

[0087] The indexing beam 128 extends along the radial axis relative to the gear 12.

[0088] When a non-zero voltage is applied between the fixed indexing portion 410 and the movable indexing portion 420 via the electrical contact pads 415 and 115, an electrostatic force is generated that attracts the movable comb 421 toward the fixed comb 411. More precisely, each pair of movable combs 421 is attracted toward the same pair of fixed combs 411. Due to the generated electrostatic force, the movable indexing portion 420 moves in a third direction (arrow C) parallel to the radial axis relative to the fixed indexing portion 410.

[0089] The movement of the movable indexing portion 420 relative to the fixed indexing portion 410 in a third direction causes elastic deformation of the third suspension 430. This elastic deformation of the suspension 430 includes bending of the flexible beam 431 that connects the movable indexing portion 420 to the frame 100. This elastic deformation causes the third suspension 430 to generate an elastic restorative force that attempts to counteract electrostatic forces. This restorative force increases with the amplitude of the elastic deformation.

[0090] When the tension between the fixed indexing portion 410 and the movable indexing portion 420 decreases or becomes zero, the electrostatic force becomes less than or zero than the elastic restorative force. As a result of the elastic restorative force generated by the third suspension, the movable indexing portion 420 moves away from the fixed indexing portion 410 in a fourth direction (arrow D) opposite to the third direction parallel to the radial axis.

[0091] When the indexing teeth 120 are connected to the movable indexing section 420 via the indexing beam 128, the indexing teeth 120 thus move continuously in a third and fourth direction by the indexing module, parallel to the radial axis.

[0092] Therefore, it is possible to alternately move the indexing teeth 120 radially relative to the wheel 12.

[0093] By appropriately controlling the drive module 200 and the engagement module 300 with a phase-shifted periodic electrical control signal, it is possible to move the drive tooth 116 with a first periodic hysteresis motion (the motion shown in Figure 18) or a second periodic hysteresis motion (the motion shown in Figure 19) that is inverted relative to the first periodic hysteresis motion.

[0094] As the drive tooth 116 moves in a first periodic motion within the hysteresis, the drive tooth 116 meshes with the consecutive teeth 121 of the gear 12, driving the gear 12 in a stepwise rotational motion in the first rotational direction.

[0095] As the teeth move in a second periodic motion within the hysteresis, the drive teeth 116 mesh with the consecutive teeth 121 of the gear 12, driving the gear 12 in a stepwise rotational motion in a second rotational direction opposite to the first rotational direction.

[0096] In parallel, the indexing module 400 is controlled by an electrical control signal that is in the opposite phase to the electrical control signal applied to the engagement module 300.

[0097] Therefore, when the drive tooth 116 is disengaged from the tooth 121 of the wheel 12, the indexing tooth 120 engages with the tooth 121 of the wheel 12. Conversely, when the drive tooth 116 is engaged with the tooth 121 of the wheel 12, the indexing tooth 120 is disengaged from the tooth 121 of the wheel 12.

[0098] Therefore, the indexing teeth 120 prevent the wheel 12 from rotating too quickly while the drive teeth 116 are disengaged from the teeth 121 of the wheel 12 (during the disengagement phase). On the other hand, the indexing teeth 120 do not form an obstruction to the rotation of the wheel 121 caused by the drive teeth 116 (during the drive phase).

[0099] The actuator 11 also includes a stopper 240 that allows the movable drive portion 220 of the drive module 200 to move in a second direction (arrow B).

[0100] The actuator 11 also includes a latch mechanism 500 for positioning the contact portion 240 with respect to the support at a predetermined position.

[0101] In Figure 3, the contact portion 240 and the latch mechanism 500 are shown as being obtained immediately after the manufacture of the micro-electromechanical system 10, that is, before the latch mechanism 500 latches and before the micro-electromechanical system is put into operation.

[0102] In this diagram, the latch mechanism 500 is in a non-latch configuration.

[0103] Furthermore, as can be seen from this diagram, in this configuration, the fingers 223 of the movable comb 221 of the drive module 200 do not engage with the fingers 213 of the fixed comb 211 of the drive module 200.

[0104] The latch mechanism 500 comprises a tappet 510 and elastic legs 511 extending from the tappet 510 along the tangential axis. In the example shown in Figure 3, the latch mechanism comprises two elastic legs 511.

[0105] Each elastic leg 511 has a free end and is equipped with a first snap-locking lug 512 positioned at the free end.

[0106] The latch mechanism 500 also includes a flexible beam 520 that connects the tappet 510 to the frame 100. In the example shown in Figure 2, the latch mechanism 500 includes two flexible beams 520. The flexible beams 520 extend parallel to each other along their radial axes.

[0107] The stopper 240 is fixed to the tappet 510. In other words, the stopper 240 is fixed to the tappet 510. More precisely, in the example shown in Figure 3, the stopper 240 and the tappet 510 are formed from a single, unique piece of material.

[0108] Furthermore, the frame 100 includes a second snap locking lug 112. In the example shown in Figure 3, the frame 100 includes two second snap locking lugs 112.

[0109] Figures 7 to 10 schematically illustrate the steps for latching the latch mechanism 500, enabling the transition of the latch mechanism 500 from an unlatched configuration (configuration shown in Figure 7) to a latched configuration (configuration shown in Figure 10).

[0110] As shown in Figure 7, a non-zero voltage is applied between the fixed drive portion 210 and the movable drive portion 220 of the drive module 200 via the electrical contact pads 115 and 215.

[0111] The applied voltage generates an electrostatic force that has the effect of moving the movable drive portion 220 of the drive module 200 relative to the fixed drive portion 210 in a first direction (arrow A) parallel to the tangential axis.

[0112] As shown in Figure 8, during its movement, the movable drive part 220 pushes the tappet 510, which moves the tappet 510 and also has the effect of moving the stopper 240 in the first direction (arrow A).

[0113] This also has the effect of pressing the first snap locking lug 512 against the second snap locking lug 112.

[0114] Due to their shapes, the first snap locking lug 512 slides on the second snap locking lug 112 by causing the elastic leg portion 511 to bend. In the example shown in Figure 8, the elastic leg portions 511 bend while moving closer to each other.

[0115] As shown in Figure 9, the bending of the elastic leg 511 pushes the first snap locking lug 512 beyond the second snap locking lug 112.

[0116] When the first snap locking lug 512 exceeds the second snap locking lug 112, the elastic leg portion 511 tends to return to its original shape. In the example shown in Figure 9, the elastic leg portions 511 are separated from each other. The separation of the elastic leg portions 511 has the effect of engaging the first snap locking lug 512 with the second snap locking lug 112.

[0117] As shown in Figure 10, the voltage applied between the fixed drive portion 210 and the movable drive portion 220 of the drive module 200 is then removed. The electrostatic force disappears.

[0118] As a result of the elastic restoring force exerted by the first suspension 230, the movable drive portion 220 of the drive module 200 moves relative to the fixed drive portion 210 of the drive module 200 in a second direction (arrow B) parallel to the tangential axis. The movable drive portion 220 of the drive module 200 moves in the second direction relative to the fixed drive portion 210 until it contacts the stopper 240.

[0119] However, the stopper 240 is held in place by the first snap locking lug 512 and the second snap locking lug 112, preventing the tappet 510 from returning to its initial position.

[0120] When the latch mechanism 500 is in a latch configuration, the stopper 240 is positioned to prevent the first movable drive part 220 from moving in a second direction to a resting position where the elastic force generated by the first suspension becomes zero.

[0121] In other words, the stopper 240 is positioned to permanently hold the first suspension 230 in an elastically deformed state. The position of the stopper 240 determines the minimum elastic restoring force exerted by the first suspension 230.

[0122] Due to the presence of the stopper 240, the elastic restoring force exerted by the first suspension 230 cannot be reduced below this minimum value.

[0123] Figure 11 schematically shows the drive module 200 before the latch of the latch mechanism 500.

[0124] As shown in this figure, the fingers 223 of the movable comb 221 are not engaged with the fingers 213 of the fixed comb 211.

[0125] Furthermore, the first suspension 230 is in a resting position. That is, the flexible beam 231 of the first suspension 230 does not deform. Therefore, the elastic restoring force exerted by the first suspension 230 is zero.

[0126] Figure 12 schematically shows the drive module 200 after the latch mechanism 500 has latched.

[0127] As shown in this figure, the fingers 223 of the movable comb 221 are partially engaged with the space provided between the fingers 213 of the fixed comb 211.

[0128] The stopper 240 prevents the movable drive part 220 from returning to its resting position, thereby holding the flexible beam 231 in an elastically deformed state. Therefore, the elastic restoring force exerted by the first suspension 230 is not zero.

[0129] Figure 13 schematically shows the strengths of different forces acting on the drive teeth 116 when the movable drive part 220 moves relative to the fixed drive part 210 in a first direction (direction of arrow A).

[0130] The forces acting on the drive tooth 116 are the electrostatic force due to the voltage applied between the fixed part 210 and the movable drive part 220, and the elastic restorative force due to the deformation of the first suspension 230.

[0131] The elastic restorative force counteracts the electrostatic force. Therefore, the strength of the driving force acting on the drive tooth 116 is the difference between the strength of the electrostatic force and the strength of the elastic restorative force.

[0132] The gray area in Figure 13 represents the driving force exerted on the drive teeth 116 relative to the first stiffness value of the first suspension 230 (beam width: 33 μm) in the first rotation direction (direction of arrow A).

[0133] As can be seen from this figure, the strength of the electrostatic force remains relatively constant during the movement of the movable drive part 220 relative to the fixed drive part 210.

[0134] On the other hand, the magnitude of the elastic restoring force increases as the movable drive part 220 moves in the first direction.

[0135] The increase in the strength of the elastic restoring force depends on the stiffness of the first suspension 230. For comparison, this figure shows the variation in the strength of the elastic restoring force with respect to a first stiffness value of the first suspension 230 (beam width = 33 μm) and the variation in the strength of the elastic restoring force with respect to a second stiffness value of the first suspension 230 (beam width = 15 μm).

[0136] Furthermore, if the movement of the movable drive part 220 is zero, the strength of the elastic restoring force is not zero. In fact, at this position, the first suspension 230 deforms due to the presence of the stopper 240.

[0137] Figure 14 schematically shows the strength of the elastic restoring force acting on the drive tooth 116 when the movable drive part 220 moves relative to the fixed drive part 210 in a second direction (direction of arrow B) opposite to the first direction.

[0138] As can be seen from this diagram, no electrostatic force is acting on the moving parts.

[0139] The movable drive part 220 moves in a second direction relative to the fixed drive part 210 solely by elastic restoring force.

[0140] The magnitude of the elastic restoring force decreases as the movable drive part 220 moves in the second direction. However, due to the presence of the stopper 240, the strength of the elastic restoring force does not become zero. The strength of the elastic restoring force remains greater than the minimum non-zero value.

[0141] As shown in this figure, the decrease in the strength of the elastic restoring force depends on the stiffness of the first suspension 230. Therefore, this figure shows the variation in the strength of the elastic restoring force with respect to a first stiffness value (beam width = 33 μm) of the first suspension.

[0142] The gray area in Figure 14 represents the driving force exerted on the drive teeth 116 relative to the first stiffness value of the first suspension 230 (beam width: 33 μm) in the second rotation direction (direction of arrow B).

[0143] Figure 15 schematically shows the strength of different forces acting on the drive teeth 116 when the movable drive part 220 moves in a first direction relative to the fixed drive part 210.

[0144] The forces acting on the drive tooth 116 are the electrostatic force generated by the tension between the fixed drive part 210 and the movable drive part 220, and the elastic restorative force due to the deformation of the first suspension 230. The elastic restorative force counteracts the electrostatic force.

[0145] This figure shows the change in the strength of the elastic restoring force for the second stiffness value (beam width = 15 μm) of the first suspension 230.

[0146] The gray area in Figure 15 shows the variation in the intensity of the driving force exerted on the drive tooth 116 in the first direction (direction of arrow A) with respect to the second stiffness value (beam width: 15 μm) of the first suspension 230. This second stiffness value, which is smaller than the first stiffness value, results in a larger gray zone (comparison of the area of ​​the gray regions in Figures 13 and 15), and therefore also results in a greater intensity of the driving force in the first direction.

[0147] Figure 16 schematically shows the strength of the elastic restoring force acting on the drive teeth 116 when the movable drive part 220 moves relative to the fixed drive part 210 in a second direction opposite to the first direction relative to the second stiffness value of the first suspension 230.

[0148] As can be seen from this diagram, no electrostatic force acts on the movable drive part 220.

[0149] The movable drive part 220 moves in a second direction relative to the fixed part 210 solely by elastic restorative force.

[0150] The magnitude of the elastic restoring force decreases as the movable drive part 220 moves in the second direction.

[0151] However, due to the presence of stopper 240, the strength of the elastic restoring force does not become zero. The strength of the elastic restoring force remains greater than the minimum non-zero value.

[0152] This figure shows the change in the strength of the elastic restoring force for the second stiffness value (beam width = 15 μm) of the first suspension 240.

[0153] The gray area in Figure 16 shows the driving force exerted on the drive teeth 116 for the second stiffness value (beam width: 15 μm) of the first suspension 230 in the second rotation direction (direction of arrow B). For comparison, the driving force in the second direction for the first stiffness value is also shown in the same figure.

[0154] Figures 13 to 16 show that as the rigidity of the first suspension increases, the driving force that helps drive the gear 12 in the first rotational direction decreases sharply.

[0155] Therefore, depending on the intended application, the stiffness of the first suspension 230 can be adjusted to facilitate better rotational drive of the gear 12 in a first rotational direction or better rotational drive of the gear 12 in a second rotational direction.

[0156] Figure 17 is a detailed view of the shape of the fingers 213 of the fixed comb 211 and the shape of the fingers 223 of the movable comb 221 of the drive module 200.

[0157] Etching techniques used for etching micro-electromechanical systems during production require a minimum gap between the fixed and movable parts of each micro-system.

[0158] For example, in the case of a micro-electromechanical system as shown in Figures 1 to 6, it is necessary to provide a minimum gap between the fingers of the fixed comb and the movable comb.

[0159] The minimum spacing Gu depends on the etching depth. For example, in the case of etching performed using the deep reactive ion etching (DRIE) method to a depth of 200 μm, the minimum spacing Gu can be approximately 4 to 6 μm.

[0160] Before the latch mechanism 500 latches, the fingers 223 of the movable comb 221 are not engaged with the fingers 213 of the fixed comb 211. The fingers 223 of the movable comb 221 are spaced a distance G1 from the nearest finger 213 of the fixed comb 211.

[0161] The distance G1 between the finger 213 of the fixed comb 211 and the finger 223 of the movable comb 221 is greater than the minimum distance Gu. The "distance" between two fingers is defined as the shortest distance separating the two fingers.

[0162] After the latch mechanism 500 latches, the fingers 223 of the movable comb 221 engage with the fingers 213 of the fixed comb 211.

[0163] Therefore, the fingers 223 of the movable comb 221 are spaced by a second spacing G2 and a third spacing G3, which are smaller than the first spacing G1, from the nearest finger 213 of the fixed comb 211. More precisely, the fingers 223 of the movable comb 221 are spaced by a second spacing G2 from the finger 213 of the fixed comb 211 located on one side of the finger 223 of the movable comb 221, and by a third spacing G3 from another finger 213 of the fixed comb 211 located on the other side of the finger 223 of the movable comb 221. The spacings G2 and G3 between the fingers 213 and 223 of the fixed comb 211 and the finger 223 of the movable comb 221 can be less than the minimum spacing Gu. The spacings G2 and / or spacing G3 may be between 0.1 and 5 μm, preferably between 1 and 3 μm. For example, the spacing G2 can be equal to 3 μm, and the spacing G3 can be equal to 4 μm.

[0164] In particular, the ratio of the thickness of fingers 213, 223 (i.e., the etching depth of the upper layer of silicon) to the distance between the fingers 213 of the fixed comb 211 and the fingers 223 of the movable comb 221 can be in the range of 50 to 400, preferably in the range of 70 to 150.

[0165] Since the electrostatic force generated by the drive module 200 is inversely proportional to the distance between the fingers 213 of the fixed comb 211 and the fingers 223 of the movable comb 221, this has the effect of increasing the driving force generated by the drive module 200 while eliminating the distance constraints imposed by the etching technique used.

[0166] The second spacing G2 may differ from the third spacing G3 in order to take into account the fact that, during the movement of the movable drive part 220 relative to the fixed drive part 210, the movement of the fingers 223 of the movable comb 221 is not perfectly linear and is not perfectly parallel to the fingers 213 of the fixed comb 211.

[0167] Figures 20 and 21 schematically show a micro-electromechanical system 10 according to another possible embodiment of the present invention.

[0168] These other embodiments differ from the embodiments shown in Figures 1 to 6 in that the drive module 200 is symmetrical with respect to an axis of symmetry parallel to the tangential axis.

[0169] As shown in the embodiments in Figures 1 to 6, the drive module 200 includes a fixed drive portion 210 and a movable drive portion 220.

[0170] The fixed drive unit 210 is fixedly attached to the support body 6.

[0171] In this embodiment, the fixed drive unit 210 comprises two first carriers 214, with a first series of fixed combs 211 extending perpendicularly from one of the first carriers 214 and a second series of fixed combs 211 extending perpendicularly from the other of the first carriers 214.

[0172] The movable drive unit 220 comprises a second carrier 224 and a plurality of movable combs 221 extending perpendicularly from the second carrier 224.

[0173] In this embodiment, the movable comb 221 includes a first set of movable combs extending from a first side of the second carrier 224 and a second set of movable combs extending from a second side of the second carrier 224 opposite to the first side. Thus, the movable comb 221 extends symmetrically on both sides of the second carrier 224.

[0174] Similarly, the fixing comb 211 of the fixing comb of the first series extends from the first side of the second carrier 224, and the fixing comb 211 of the fixing comb of the second series extends from the second side of the second carrier 224 opposite to the first side. Thus, the fixing comb 211 extends symmetrically on both sides of the second carrier 224.

[0175] The actuator 11 also includes a first suspension 230 that connects the movable drive portion 220 to the frame 100. The first suspension 230 comprises four flexible beams 231 that extend parallel to the shank 222 of the movable comb 221. The flexible beams 231 connect the second carrier 224 to the frame 100. The four flexible beams 231 include two flexible beams extending from a first side of the second carrier 224 and two other flexible beams extending from a second side of the second carrier 224. Thus, the first suspension 230 is symmetrical with respect to an axis of symmetry parallel to the tangential axis.

[0176] The movable combs 221 are arranged alternately between the fixed combs 211; that is, the movable combs 221 are positioned alternately with the fixed combs 211. Furthermore, the movable combs 221 and fixed combs 211 are arranged in pairs, with each pair comprising a fixed comb 211 and its associated movable comb 221. More precisely, the fingers 213 of each fixed comb 211 in a pair extend with their free ends directed toward the fingers 223 of the associated movable comb 221 in the same pair. Similarly, the fingers 223 of a pair of movable combs 221 extend with their free ends directed toward the fingers 213 of the fixed comb 211 in the same pair. Furthermore, the fingers 213 of the fixed combs 211 and the fingers 223 of the fixed combs 221 extend parallel to the tangential axis.

[0177] Figure 20 schematically shows the drive module 200 before the latch of the latch mechanism 500.

[0178] As shown in this figure, the fingers 223 of the movable comb 221 are not engaged with the fingers 213 of the fixed comb 211.

[0179] Furthermore, the first suspension 230 is in a resting position. That is, the flexible beam 231 of the first suspension 230 does not deform. Therefore, the elastic restoring force exerted by the first suspension 230 is zero.

[0180] Figure 21 schematically shows the drive module 200 after the latch mechanism 500 has latched.

[0181] As shown in this figure, the fingers 223 of the movable comb 221 are partially engaged with the space provided between the fingers 213 of the fixed comb 211.

[0182] The stopper 240 prevents the movable drive part 220 from returning to its resting position, thereby holding the flexible beam 231 in an elastically deformed state. Therefore, the elastic restoring force exerted by the first suspension 230 is not zero.

[0183] One advantage of this embodiment is that, due to the symmetrical configuration of the first suspension 230, the movement of the fingers 223 of the movable comb 221 is perfectly linear and parallel to the fingers 213 of the fixed comb 211 while the movable drive portion 220 moves relative to the fixed drive portion 210.

[0184] In other words, the second carrier 224 is constrained to move along the tangential axis and cannot move along the radial axis.

[0185] Therefore, the spacings G2 and G3 between the fingers 213 and 223 of the fixed comb 211 and the movable comb 221 can be made even smaller. Also, the second spacing G2 and the third spacing G3 can be made equal. The spacings G2 and G3 (shown in Figure 17) can be less than 1 μm.

[0186] This allows the electrostatic force generated by the drive module 200 to be increased.

[0187] Figure 22 schematically shows examples of electrical control signals for the drive module, the engagement module, and the indexing module.

[0188] In Figure 22, each electrical control signal is a voltage electrical control signal. Therefore, the graph in Figure 22 shows the voltage fluctuations of each electrical control signal as a function of time. Each electrical control signal is periodic and has essentially a square wave shape.

[0189] For example, the electrical control signal of the drive module alternates between a minimum voltage value (e.g., Vmin=0) and a maximum voltage value (e.g., Vmax=110 volts).

[0190] Figure 23 more accurately shows the voltage fluctuations of each electrical control signal as a function of time over a period of time.

[0191] Figure 24 schematically shows the movement over time of the movable drive portion 220 of the drive module 200, the movable engagement portion 320 of the engagement module 300, and the movable portion 420 of the indexing module 400.

[0192] These movements were obtained when actuator 11 was controlled by the same electrical control signals shown in Figures 22 and 23.

[0193] Figure 24 shows the rebound of the movable drive portion 220 of the drive module 200. These rebounds essentially occur when the movable drive portion 220 reaches the end of its stroke. More precisely, these rebounds are visible when the movable drive portion 220 contacts the stopper 240 during elemental motion in the second direction (arrow B), i.e., when the movable drive portion 220 returns to its initial position as a result of the elastic restorative force generated by the elastically deformed first suspension 230.

[0194] Figure 24 also shows that the movable engaging portion 320 of the engaging module 300 and the movable indexing portion 420 of the indexing module 400 are also subject to residual vibration.

[0195] These rebounds or residual vibrations are detrimental to the proper operation of the actuator 11.

[0196] On the one hand, before commanding the movement of the movable part in the reverse direction, it is necessary to wait for these rebounds or vibrations to be sufficiently damped, which limits the frequency range in which the actuator can be controlled.

[0197] On the other hand, rebound generates repeated impacts between mechanical parts, causing premature wear of contacting surfaces and shortening the lifespan of the micro-electromechanical system.

[0198] Figure 25 schematically shows the movement of the movable drive portion 220 of the drive module 200 as a function of the voltage value of the electrical control signal applied between the movable drive portion 220 and the fixed drive portion 210.

[0199] This figure, in more detail, shows the amplitude of movement of the movable drive part 220 relative to the fixed drive part 210 as the voltage value of the electrical control signal applied to the drive module 200 increases gradually and linearly over time.

[0200] As shown in Figure 25, when the voltage value of the electrical control signal is less than the threshold voltage value Vdebut, the movable drive part 220 does not move relative to the fixed drive part 210. In fact, the electrostatic force generated between the movable drive part 220 and the fixed drive part 210 is insufficient to overcome the elastic restoring force generated by the first suspension 230, and therefore insufficient to move the movable drive part 220 relative to the fixed drive part 210. In other words, the first suspension 230 is subjected to an elastic prestress that the electrostatic force must overcome in order to allow the movable drive part 220 to move relative to the fixed drive part 210.

[0201] When the voltage value of the electrical control signal falls between the threshold voltage value Vdebut and the threshold voltage value Vfin, the movable drive part 220 moves relative to the fixed drive part 210. In fact, the electrostatic force generated between the movable drive part 220 and the fixed drive part 210 causes the movement of the movable drive part 220 relative to the fixed drive part 210. The amplitude of the movement of the movable drive part 220 relative to the fixed drive part 210 increases continuously in accordance with the voltage value of the electrical control signal.

[0202] If the voltage value of the control signal is greater than the voltage Vfin, the movable drive part 220 will no longer move relative to the fixed drive part 210. In fact, the movable drive part is in contact with the frame 100. Therefore, an increase in electrostatic force will not cause further movement of the movable drive part 220 relative to the fixed drive part 210.

[0203] Figure 26 schematically shows the movement of the movable engaging portion 320 of the engaging module 300 as a function of the voltage value of the electrical control signal applied to the engaging module 300.

[0204] For the drive module 200, it is possible to determine a threshold voltage value Vdebut at which the electrostatic force generated between the movable engagement portion 320 and the fixed engagement portion 310 is insufficient to move the movable engagement portion 320 relative to the fixed engagement portion 310.

[0205] In the case of the engagement module 300, when the voltage value of the electrical control signal is less than the threshold voltage value Vdebut, the movable engagement portion 320 does not move relative to the fixed engagement portion 310. In fact, since the fingers 323 of the movable comb 321 do not engage with the fingers 313 of the fixed comb 311, the electrostatic force generated between the fixed comb 311 and the movable comb 321 is very small.

[0206] It is also possible to determine the threshold voltage value Vfin at which the movable engaging portion 320 contacts the frame 100.

[0207] When the voltage of the control signal falls between the threshold voltage value Vdebut and the threshold voltage value Vfin, the movable engagement portion 320 moves relative to the fixed engagement portion 310. The amplitude of the movement of the movable engagement portion 320 relative to the fixed engagement portion 310 increases continuously in accordance with the value of the voltage of the electrical control signal.

[0208] Figure 27 schematically shows the movement of the movable indexing portion 420 of the indexing module 400 as a function of the voltage value of the electrical control signal applied to the indexing module 400.

[0209] With respect to the engagement module 300, it is possible to determine a threshold voltage value Vdebut below which the electrostatic force generated between the movable indexing portion 420 and the fixed indexing portion 410 is insufficient to cause movement of the movable indexing portion 420 relative to the fixed indexing portion 410.

[0210] It is also possible to determine the threshold voltage value Vfin at which the movable indexing portion 420 contacts the frame 100.

[0211] When the voltage of the control signal falls between the threshold voltage value Vdebut and the threshold voltage value Vfin, the movable indexing portion 420 moves relative to the fixed indexing portion 410. The amplitude of the movement of the movable indexing portion 420 relative to the fixed indexing portion 410 increases continuously with the value of the voltage of the electrical control signal.

[0212] Figure 28 schematically shows the electrical control signals for the drive module 200, the engagement module 300, and the indexing module 400 according to one possible embodiment of the present invention.

[0213] As shown in this figure, the electrical control signal of the drive module 200 alternates between a minimum voltage value (e.g., Vmin=0) and a maximum voltage value (e.g., Vmax=110 volts).

[0214] During the transition from the maximum voltage value Vmax to the minimum voltage value Vmin, the voltage value of the electrical control signal decreases monotonically from the maximum voltage value Vmax to the minimum voltage value Vmin.

[0215] In addition, during this decrease, the electrical control signal is The first average slope between the maximum voltage value Vmax and the threshold voltage value Vfin defined for the drive module (in this example, Vfin ≈ 0.83 × Vmax), A second mean slope (in this example, Vdebut ≈ 0.41 × Vmax) between the threshold voltage value Vfin and the threshold voltage value Vdebut, which has a smaller absolute value than the first mean slope, The drive module has a third mean slope (Vmin=0 in this example) whose absolute value is greater than the second mean slope between the defined threshold voltage value Vdebut and the minimum voltage value Vmin.

[0216] The first mean gradient is defined as the average of the instantaneous gradients of the electrical control signal over the period [Tmax, Tfin] during which the value of the electrical control signal transitions from value Vmax to value Vfin. In other words, the first mean gradient is equal to (Vfin - Vmax) / (Tfin - Tmax), where (Tfin - Tmax) is the time it takes for the electrical control signal to transition from value Vmax to value Vfin.

[0217] The second mean gradient is defined as the average of the instantaneous gradients of the electrical control signal over the period [Tfin, Tdebut] during which the value of the electrical control signal transitions from value Vfin to value Vdebut. In other words, the second mean gradient is equal to (Vdebut-Vfin) / (Tdebut-Tfin), where (Tdebut-Tfin) is the time it takes for the electrical control signal to transition from value Vfin to value Vdebut.

[0218] The third mean gradient is defined as the average of the instantaneous gradients of the electrical control signal over the period [Tdebut, Tmin] during which the value of the electrical control signal transitions from value Vdebut to value Vmin. In other words, the third mean gradient is equal to (Vmin - Vdebut) / (Tmin - Tdebut), where (Tmin - Tdebut) is the time it takes for the electrical control signal to transition from value Vdebut to value Vmin.

[0219] In the example shown in Figure 28, the electrical control signal is linear over each period [Tmax, Tfin], [Tfin, Tdebut], and [Tdebut, Tmin]. In this case, the first mean slope is equal to the instantaneous slope of the signal that is constant over the period [Tmax, Tfin], the second mean slope is equal to the instantaneous slope of the signal that is constant over the period [Tfin, Tdebut], and the third mean slope is equal to the instantaneous slope of the signal that is constant over the period [Tdebut, Tmin].

[0220] However, other forms of electrical control signals are certainly possible, for example, in which the electrical control signal is not linear over each period.

[0221] Figure 28 shows several possible values ​​for the second mean gradient.

[0222] As shown in Figure 28, the electrical control signals for the engagement module 300 and the indexing module 400 have a similar configuration to the electrical control signals for the drive module 200.

[0223] As shown in this figure, the electrical control signals of the engagement module 300 (each corresponding to an indexing module 400) alternate between a minimum voltage value (e.g., Vmin=0) and a maximum voltage value (e.g., Vmax=110 volts).

[0224] During the transition from the maximum voltage value to the minimum voltage value, the voltage value of the electrical control signal decreases monotonically from the maximum voltage value Vmax to the minimum voltage value Vmin.

[0225] In addition, during this decrease, the electrical control signal is The first average slope between the maximum voltage value and the threshold voltage value Vfin defined for each engagement module 300 (each indexing module 400) (in this example, Vfin ≈ 0.91 × Vmax), A second mean slope (in this example, Vdebut ≈ 0.27 × Vmax) between the threshold voltage value Vfin and the threshold voltage value Vdebut, which has a smaller absolute value than the first mean slope, The engagement module 300 (each indexing module 400) has a third mean slope, which has a larger absolute value than the second mean slope, between the threshold voltage value Vdebut and the minimum voltage value Vmin (Vmin=0 in this example), defined for each engagement module 300.

[0226] Figure 28 shows several possible values ​​for the second mean gradient.

[0227] Figure 29 is a schematic diagram showing the amplitude of the movement of the movable drive part 220 relative to the fixed drive part 210 over time, obtained when the drive module 200 is controlled by the electrical control signal in Figure 28.

[0228] Depending on the second average gradient selected for the electrical control signal applied to the drive module 200 (i.e., depending on the time it takes for the control signal to transition from voltage value Vfin to voltage value Vdebut), the bounce of the movable part 220 is more or less attenuated.

[0229] It is possible to determine the optimal value of the second mean gradient (or the optimal time it takes for the control signal to transition from voltage value Vfin to voltage value Vdebut), i.e., the value of the second mean gradient that allows for the best attenuation of these bounces.

[0230] In the example shown in Figure 29, the time it takes for the control signal to transition from voltage value Vfin to voltage value Vdebut is 0.42 ms, which allows for the best damping of the rebound. This time is substantially equal to one natural free vibration period of the movable drive part 220 relative to the fixed drive part 210. For example, this time falls within the range of 0.7 to 1.3 times the natural free vibration period of the movable drive part 220 relative to the fixed drive part 210.

[0231] Similarly, Figure 30 is a schematic diagram showing the amplitude of movement of the movable engagement portion 320 relative to the fixed engagement portion 310 of the engagement module 300 over time, obtained when the engagement module 300 is controlled by the electrical control signal of Figure 28.

[0232] In this example, the time it takes for the control signal to transition from voltage value Vfin to voltage value Vdebut is 0.56 ms, which allows for the best damping of the vibration. This time is substantially equal to one natural free vibration period of the movable engagement portion 320 relative to the fixed engagement portion 310.

[0233] Figure 31 is a schematic diagram showing the electrical control signals for the drive module and the engagement module according to another possible embodiment of the present invention.

[0234] In this embodiment, as in the previously described embodiment, the control signal alternates between a minimum voltage value Vmin and a maximum voltage value Vmax.

[0235] However, in this embodiment, during the transition from the minimum voltage value to the maximum voltage value, the voltage value of the electrical control signal increases monotonically from the minimum voltage value to the maximum voltage value.

[0236] In addition, the voltage value of the electrical control signal is The fourth mean slope between the minimum voltage value Vmin and the threshold voltage value Vdebut, A fifth mean slope between threshold voltage value Vdebut and threshold voltage value Vfin, the fifth mean slope having an absolute value smaller than the fourth mean slope, It has a sixth mean slope, which has a larger absolute value than the fifth mean slope, between the threshold voltage value Vfin and the maximum voltage value Vmax.

[0237] The fourth mean gradient is defined as the average of the instantaneous gradients of the electrical control signal over the period [Tmin, Tdebut] during which the value of the electrical control signal transitions from value Vmin to value Vdebut. In other words, the fourth mean gradient is equal to (Vdebut-Vmin) / (Tdebut-Tmin), where (Tdebut-Tmin) is the time it takes for the electrical control signal to transition from value Vmin to value Vdebut.

[0238] The fifth mean gradient is defined as the average of the instantaneous gradients of the electrical control signal over the period [Tdebut, Tfin] during which the value of the electrical control signal transitions from value Vdebut to value Vfin. In other words, the fifth mean gradient is equal to (Vfin - Vdebut) / (Tfin - Tdebut), where (Tfin - Tdebut) is the time it takes for the electrical control signal to transition from value Vdebut to value Vfin.

[0239] The sixth mean gradient is defined as the average of the instantaneous gradients of the electrical control signal over the period [Tfin, Tmax] during which the value of the electrical control signal transitions from value Vfin to value Vmax. In other words, the sixth mean gradient is equal to (Vmax-Vfin) / (Tmax-Tfin), where (Tmax-Tfin) is the time it takes for the electrical control signal to transition from value Vfin to value Vmax.

[0240] In the example shown in Figure 31, the electrical control signal is linear over each period [Tmin, Tdebut], [Tdebut, Tfin], and [Tfin, Tmax]. In this case, the fourth mean slope is equal to the instantaneous slope of the signal that is constant over the period [Tmin, Tdebut], the fifth mean slope is equal to the instantaneous slope of the signal that is constant over the period [Tdebut, Tfin], and the sixth mean slope is equal to the instantaneous slope of the signal that is constant over the period [Tfin, Tmax].

[0241] However, other forms of electrical control signals are certainly possible, for example, in which the electrical control signal is not linear over each period.

[0242] Figure 32 schematically shows a control circuit 13 suitable for controlling the actuator 11 of the micro-electromechanical system 10.

[0243] In this example, the control circuit 13 is Attenuation circuit 131 and, A power supply circuit 132 comprising a charge pump converter and a voltage regulator, configured to generate a high-voltage power supply signal, A commutation circuit 133 equipped with a high-voltage switch, configured to selectively connect the actuator 11 to the output of the power supply circuit 132 and the attenuation circuit 131, A starting circuit 134 configured to control the damping circuit, Voltage level shift circuit 135, It comprises a low-voltage digital microprocessor 136.

[0244] The attenuation circuit 131, power supply circuit 132, commutation circuit 133, starting circuit 134, and voltage level shift circuit 135 can all be components of the same ASIC circuit.

[0245] The digital processor 136 (also known as the "low-voltage digital core") is a low-voltage programmable digital processor configured to control different circuits within the ASIC circuitry.

[0246] The power supply circuit 132 is configured to generate a high-voltage power supply signal, for example, with a maximum voltage of 125 volts, which may be adjusted between two values ​​lower than the maximum voltage, and which features a variable rise time of less than 1 ms depending on the operating frequency of the charge pump.

[0247] The charge pump is an analog circuit that includes a capacitor, which enables it to amplify the voltage of the electrical control signal applied to the input of the commutation circuit 133 (a charge pump is also called a "voltage multiplier"). This analog circuit enables it to transition, for example, from the input voltage of a conventional battery (button cell) of 1.5 to 3 volts to an output voltage of over 100 volts required to supply modules 200, 300, and 400 of the actuator 11.

[0248] The switches in the commutation circuit 133 are configured to enable commutation between the high-voltage terminal (110 volts) required for the voltage rise of the electrical control signal applied to the actuator 11 and the attenuation circuit 131. These switches include, for example, one or more MOSFET power transistors capable of withstanding high voltages.

[0249] The starting circuit 134 (also called the "VDD bootstrap") is configured to control the MOSFET transistors of the attenuation circuit 131. The starting circuit 134 is an analog circuit that enables the low-voltage digital control signal generated by the digital processor 136 to be fitted, converted, and injected into the gates of the MOSFET transistors of the attenuation circuit 131.

[0250] The voltage level shifter circuit 135 (also called the "high-voltage level shifter") is an analog circuit configured to convert a low-voltage digital control signal generated by the digital processor 136 into a high-voltage control signal applied to the gate of the MOSFET transistor in the commutation circuit 133.

[0251] FIG. 33 schematically shows an attenuation circuit 131 forming part of the control circuit 13 of FIG. 18.

[0252] In this figure, the actuator 11 is assimilated to a capacitor. In fact, each of the drive module 200, the engagement module 300, and the indexing module comprises a movable part and a fixed part. The movable part and the fixed part can be assimilated to plates of a capacitor.

[0253] In FIG. 33, only the drive module 200 is shown. However, the schematic diagram of the attenuation circuit 131 is the same for all three modules.

[0254] The attenuation circuit 131 comprises a diode D1, a resistor R1, and a MOSFET transistor Q1. The diode D1, the resistor R1, and the MOSFET transistor Q1 are electrically connected in a parallel assembly between the commutation circuit 133 and ground.

[0255] The MOSFET transistor Q1 is controlled by a starting circuit 134. The starting circuit 134 is connected to the gate of the transistor and is configured to control the transistor so as to selectively block or activate the transistor.

[0256] When the MOSFET transistor Q1 is cut off, no current flows between the drain and source of the transistor.

[0257] When the MOSFET transistor Q1 is activated, current can pass through the transistor.

[0258] The operation of the control circuit 13 is as follows.

[0259] The MOSFET transistor Q1 is initially cut off.

[0260] When the voltage of the high-voltage power supply signal transitions from the minimum voltage value (Vmin) to the maximum voltage value (Vmax), the commutation module 133 is in a first configuration in which the commutation module 133 connects the actuator 11 to the output of the power supply circuit 132. Accordingly, the actuator 11 is supplied by the high-voltage power supply signal generated by the power supply circuit 132.

[0261] When the voltage of the high-voltage power supply signal transitions from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), the commutation circuit 133 transitions to a second configuration in which the commutation module 133 connects the actuator 11 to the damping circuit 131.

[0262] Accordingly, when the commutation circuit 133 is in the second configuration, the drive module 200 discharges via the damping circuit 131.

[0263] The discharge of the drive module 200 occurs in three successive phases.

[0264] Initially, the voltage between the fixed drive portion 210 and the movable drive portion 220 is equal to the maximum voltage value Vmax. During discharge of the drive module 200, the voltage between the fixed drive portion 210 and the movable drive portion 220 decreases.

[0265] As long as the voltage between the fixed drive portion 210 and the movable drive portion 220 is greater than the threshold voltage value Vfin (the first phase), the discharge current of the actuator 11 passes through the diode D1. The voltage at the terminals of the drive module 200 decreases sharply from the maximum voltage value Vmax to the threshold voltage value Vfin. The variation of the voltage at the terminals of the drive module 200 from the maximum voltage value Vmax to the threshold voltage value Vfin has a first slope. In this example, the first average slope is quasi-vertical. In other words, the first average slope is less than -1 V / μs. The time (Tfin-Tmax) taken for the electrical control signal to transition from the maximum voltage value Vmax to the threshold voltage value Vfin is less than 50 μs, or even less than 10 μs.

[0266] When the voltage between the fixed drive part 210 and the movable drive part 220 falls below the threshold voltage value Vfin (second phase), the diode D1 is no longer used. The discharge current of the actuator 11 passes through the resistor R1. The voltage between the fixed drive part 210 and the movable drive part 220 decreases from the threshold voltage value Vfin to the threshold voltage value Vdebut. The voltage fluctuation at the terminals of the drive module 200 has a second mean slope that depends on the value of resistor R1. The second mean slope has a smaller absolute value than the first mean slope. In other words, the voltage drop between the fixed drive part 210 and the movable drive part 220 is more gradual than in the first phase. Resistor R1 plays a role in damping the movement of the movable drive part 220 relative to the fixed drive part 210.

[0267] When the voltage between the fixed drive part 210 and the movable drive part 220 falls below the threshold voltage value Vdebut (third phase), the MOSFET transistor Q1 is activated. This causes the discharge current of the actuator 11 to pass through the MOSFET transistor Q1. The voltage at the terminals of the drive module 200 drops sharply from the threshold voltage value Vdebut to the minimum voltage value Vmin. The voltage fluctuation at the terminals of the drive module 200 has a third mean slope. In this example, the third slope is quasi-vertical. In other words, the third mean slope is less than -1V / μs. The time it takes for the electrical control signal to transition from the maximum voltage value Vdebut to the threshold voltage value Vmin (Tmin-Tdebut) is less than 50μs, or even less than 10μs. The absolute value of the third slope is larger than that of the second slope.

[0268] In practice, the starting circuit 134 controls the MOSFET transistor Q1 so that it is blocked during the first and second phases and activated during the third phase. For this purpose, the starting circuit 134 generates an electrical control signal with a suitable duration for alternately shutting off and starting the MOSFET transistor Q1 in synchronization with the high-voltage power supply signal generated by the power supply circuit 132. The synchronization of the two signals is achieved by controlling the power supply circuit 132 and the starting circuit 134 by the digital processor 136.

Claims

1. A method for controlling a micro-electromechanical system (10) comprising a support (6) and an actuator (11), The actuator (11) is A frame (100) fixedly attached to the support (6), The fixing portion (210, 310, 410) is fixedly attached to the support (6), A movable part (220, 320, 420) is movably attached to the support (6), The system includes a suspension (230, 330, 430) that connects the aforementioned movable parts (220, 320, 420) to the support (6), The aforementioned method, A step of applying an electrical control signal between the fixed portion (210, 310, 410) and the movable portion (220, 320, 420), wherein the electrical control signal alternately takes a maximum voltage value (Vmax) and a minimum voltage value (Vmin), As the electrical control signal transitions from the minimum voltage value (Vmin) to the maximum voltage value (Vmax), the electrostatic force generated between the movable parts (220, 320, 420) and the fixed parts (210, 310, 410) causes the movable parts (220, 320, 420) to move in a first direction relative to the fixed parts (210, 310, 410), and this movement of the movable parts (220, 320, 420) relative to the fixed parts (210, 310, 410) causes elastic deformation of the suspension (230, 330, 430). During the transition from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), the voltage value of the electrical control signal monotonically decreases from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), and during that time, The first average slope between the maximum voltage value (Vmax) and the first threshold voltage value (Vfin), A second mean slope between the first threshold voltage value (Vfin) and the second threshold voltage value (Vdebut), having an absolute value smaller than the first mean slope, A third mean slope between the second threshold voltage value (Vdebut) and the minimum voltage value (Vmin), having an absolute value greater than the second mean slope, It has a series of, When the electrical control signal transitions from the first threshold voltage value (Vfin) to the second threshold voltage value (Vdebut), the elastic restoring force generated by the elastically deformed suspension (230, 330, 430) resists the electrostatic force, resulting in the movable part (220, 320, 420) moving in a second direction opposite to the first direction relative to the fixed part (210, 310, 410). The first threshold voltage value (Vfin) is, If the electrical control signal takes a voltage value greater than the first threshold voltage value (Vfin), the electrostatic force generated between the movable parts (220, 320, 420) and the fixed parts (210, 310, 410) is selected to be sufficient to hold the movable parts (220, 320, 420) in contact with the frame (100). When the electrical control signal takes a voltage value smaller than the first threshold voltage value (Vfin), the electrostatic force generated between the movable parts (220, 320, 420) and the fixed parts (210, 310, 410) is selected to be insufficient to hold the movable parts (220, 320, 420) in contact with the frame (100). method.

2. A method for controlling a micro-electromechanical system (10) comprising a support (6) and an actuator (11), The actuator (11) is The fixing portion (210, 310, 410) is fixedly attached to the support (6), A movable part (220, 320, 420) is movably attached to the support (6), The system includes a suspension (230, 330, 430) that connects the aforementioned movable parts (220, 320, 420) to the support (6), The aforementioned method, A step of applying an electrical control signal between the fixed portion (210, 310, 410) and the movable portion (220, 320, 420), wherein the electrical control signal alternately takes a maximum voltage value (Vmax) and a minimum voltage value (Vmin), As the electrical control signal transitions from the minimum voltage value (Vmin) to the maximum voltage value (Vmax), the electrostatic force generated between the movable parts (220, 320, 420) and the fixed parts (210, 310, 410) causes the movable parts (220, 320, 420) to move in a first direction relative to the fixed parts (210, 310, 410), and this movement of the movable parts (220, 320, 420) relative to the fixed parts (210, 310, 410) causes elastic deformation of the suspension (230, 330, 430). During the transition from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), the voltage value of the electrical control signal monotonically decreases from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), and during that time, The first average slope between the maximum voltage value (Vmax) and the first threshold voltage value (Vfin), A second mean gradient between the first threshold voltage value (Vfin) and the second threshold voltage value (Vdebut), having an absolute value smaller than the first mean gradient, wherein the electrical control signal is selected to transition from the first threshold voltage value (Vfin) to the second threshold voltage value (Vdebut) in a time substantially equal to one natural period of free vibration of the movable parts (220, 320, 420) relative to the fixed parts (210, 310, 410), A third mean slope between the second threshold voltage value (Vdebut) and the minimum voltage value (Vmin), having an absolute value greater than the second mean slope, It has a series of, When the electrical control signal transitions from the first threshold voltage value (Vfin) to the second threshold voltage value (Vdebut), the elastic restoring force generated by the elastically deformed suspension (230, 330, 430) resists the electrostatic force, resulting in the movable part (220, 320, 420) moving in a second direction opposite to the first direction relative to the fixed part (210, 310, 410). method.

3. A method for controlling a micro-electromechanical system (10) comprising a support (6) and an actuator (11), The actuator (11) is The fixing portion (210, 310, 410) is fixedly attached to the support (6), A movable part (220, 320, 420) is movably attached to the support (6), The system includes a suspension (230, 330, 430) that connects the aforementioned movable parts (220, 320, 420) to the support (6), The aforementioned method, A step of applying an electrical control signal between the fixed portion (210, 310, 410) and the movable portion (220, 320, 420), wherein the electrical control signal alternately takes a maximum voltage value (Vmax) and a minimum voltage value (Vmin), As the electrical control signal transitions from the minimum voltage value (Vmin) to the maximum voltage value (Vmax), the electrostatic force generated between the movable parts (220, 320, 420) and the fixed parts (210, 310, 410) causes the movable parts (220, 320, 420) to move in a first direction relative to the fixed parts (210, 310, 410), and this movement of the movable parts (220, 320, 420) relative to the fixed parts (210, 310, 410) causes elastic deformation of the suspension (230, 330, 430). During the transition from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), the voltage value of the electrical control signal monotonically decreases from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), and during that time, The first average slope between the maximum voltage value (Vmax) and the first threshold voltage value (Vfin), A second mean gradient between the first threshold voltage value (Vfin) and the second threshold voltage value (Vdebut), having an absolute value smaller than the first mean gradient, wherein the electrical control signal is selected to transition from the first threshold voltage value (Vfin) to the second threshold voltage value (Vdebut) within a time range of 0.7 to 1.3 times one natural period of the free vibration of the movable parts (220, 320, 420) relative to the fixed parts (210, 310, 410), A third mean slope between the second threshold voltage value (Vdebut) and the minimum voltage value (Vmin), having an absolute value greater than the second mean slope, It has a series of, When the electrical control signal transitions from the first threshold voltage value (Vfin) to the second threshold voltage value (Vdebut), the elastic restoring force generated by the elastically deformed suspension (230, 330, 430) resists the electrostatic force, resulting in the movable part (220, 320, 420) moving in a second direction opposite to the first direction relative to the fixed part (210, 310, 410). method.

4. During the transition from the minimum voltage value (Vmin) to the maximum voltage value (Vmax), the voltage value of the electrical control signal increases monotonically from the minimum voltage value (Vmin) to the maximum voltage value (Vmax), and during that time, The fourth average slope between the minimum voltage value (Vmin) and the second threshold voltage value (Vdebut), A fifth mean slope between the second threshold voltage value (Vdebut) and the first threshold voltage value (Vfin), the absolute value of which is smaller than the fourth mean slope, A sixth mean slope between the first threshold voltage value (Vfin) and the maximum voltage value (Vmax) has an absolute value greater than the fifth mean slope, Having consecutive As the electrical control signal transitions from the second threshold voltage value (Vdebut) to the first threshold voltage value (Vfin), the electrostatic force generated between the movable parts (220, 320, 420) and the fixed parts (210, 310, 410) causes the movable parts (220, 320, 420) to move in the first direction relative to the fixed parts (210, 310, 410). The method according to any one of claims 1 to 3.

5. The second threshold voltage value (Vdebut) is, When the electrical control signal takes a voltage value smaller than the second threshold voltage value (Vdebut), the electrostatic force generated between the movable parts (220, 320, 420) and the fixed parts (210, 310, 410) is selected to be insufficient to move the movable parts (220, 320, 420) relative to the fixed parts (210, 310, 410). If the electrical control signal takes a voltage value greater than the second threshold voltage value (Vdebut), the electrostatic force generated between the movable part (220, 320, 420) and the fixed part (210, 310, 410) is selected to be sufficient to move the movable part (220, 320, 420) relative to the fixed part (210, 310, 410). The method according to any one of claims 1 to 3.

6. The electrical control signal applied between the fixed portion (210, 310, 410) and the movable portion (220, 320, 420) is periodic, causing the movable portion (220, 320, 420) to alternately move in a first direction as a result of the electrostatic force and in a second direction as a result of the elastic restoring force. The method according to any one of claims 1 to 3.

7. It is a device, A micro-electromechanical system (10) comprising a support (6) and an actuator (11), wherein the actuator (11) comprises a frame (100) fixedly attached to the support (6), fixed portions (210, 310, 410) fixedly attached to the support (6), movable portions (220, 320, 420) movably attached to the support (6), and suspensions (230, 330, 430) connecting the movable portions (220, 320, 420) to the support (6), and the micro-electromechanical system (10), The system includes a control circuit (13) that can be connected to the actuator (11) for applying an electrical control signal between the fixed portion (210, 310, 410) and the movable portion (220, 320, 420), The electrical control signal alternates between a maximum voltage value (Vmax) and a minimum voltage value (Vmin), and as the electrical control signal transitions from the minimum voltage value (Vmin) to the maximum voltage value (Vmax), the electrostatic force generated between the movable part (220, 320, 420) and the fixed part (210, 310, 410) causes the movable part (220, 320, 420) to move in a first direction relative to the fixed part (210, 310, 410), and the movable part ( The movement of the 220, 320, 420) causes elastic deformation of the suspension (230, 330, 430), and when the electrical control signal transitions from a first threshold voltage value (Vfin) to a second threshold voltage value (Vdebut), the elastic restoring force generated by the elastically deformed suspension (230, 330, 430) resists the electrostatic force, resulting in the movable part (220, 320, 420) moving in a second direction opposite to the first direction relative to the fixed part (210, 310, 410). During the transition from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), the voltage value of the electrical control signal decreases monotonically from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), and during that time, The first average slope between the maximum voltage value (Vmax) and the first threshold voltage value (Vfin), A second mean slope between the first threshold voltage value (Vfin) and the second threshold voltage value (Vdebut), having an absolute value smaller than the first mean slope, The system has a third average gradient between the second threshold voltage value (Vdebut) and the minimum voltage value (Vmin), the third average gradient having a larger absolute value than the second average gradient, The first threshold voltage value (Vfin) is, When the control signal takes a voltage value greater than the first threshold voltage value (Vfin), the electrostatic force generated between the movable parts (220, 320, 420) and the fixed parts (210, 310, 410) is selected to be sufficient to hold the movable parts (220, 320, 420) in contact with the frame (100). If the control signal takes a voltage value smaller than the first threshold voltage value (Vfin), the electrostatic force generated between the movable parts (220, 320, 420) and the fixed parts (210, 310, 410) is selected to be insufficient to hold the movable parts (220, 320, 420) in contact with the frame (100). device.

8. It is a device, A micro-electromechanical system (10) comprising a support (6) and an actuator (11), wherein the actuator (11) comprises a fixed portion (210, 310, 410) fixedly attached to the support (6), a movable portion (220, 320, 420) movably attached to the support (6), and a suspension (230, 330, 430) connecting the movable portion (220, 320, 420) to the support (6), The system includes a control circuit (13) that can be connected to the actuator (11) for applying an electrical control signal between the fixed portion (210, 310, 410) and the movable portion (220, 320, 420), The electrical control signal alternates between a maximum voltage value (Vmax) and a minimum voltage value (Vmin), and as the electrical control signal transitions from the minimum voltage value (Vmin) to the maximum voltage value (Vmax), the electrostatic force generated between the movable part (220, 320, 420) and the fixed part (210, 310, 410) causes the movable part (220, 320, 420) to move in a first direction relative to the fixed part (210, 310, 410), and the movable part ( The movement of the 220, 320, 420) causes elastic deformation of the suspension (230, 330, 430), and when the electrical control signal transitions from a first threshold voltage value (Vfin) to a second threshold voltage value (Vdebut), the elastic restoring force generated by the elastically deformed suspension (230, 330, 430) resists the electrostatic force, resulting in the movable part (220, 320, 420) moving in a second direction opposite to the first direction relative to the fixed part (210, 310, 410). During the transition from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), the voltage value of the electrical control signal decreases monotonically from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), and during that time, The first average slope between the maximum voltage value (Vmax) and the first threshold voltage value (Vfin), A second mean slope between the first threshold voltage value (Vfin) and the second threshold voltage value (Vdebut), having an absolute value smaller than the first mean slope, The system has a third average gradient between the second threshold voltage value (Vdebut) and the minimum voltage value (Vmin), the third average gradient having a larger absolute value than the second average gradient, The average gradient of the above 2 is, The electrical control signal is selected to transition from the first threshold voltage value (Vfin) to the second threshold voltage value (Vdebut) within a time substantially equal to one natural period of free vibration of the movable parts (220, 320, 420) relative to the fixed parts (210, 310, 410). device.

9. It is a device, A micro-electromechanical system (10) comprising a support (6) and an actuator (11), wherein the actuator (11) comprises a fixed portion (210, 310, 410) fixedly attached to the support (6), a movable portion (220, 320, 420) movably attached to the support (6), and a suspension (230, 330, 430) connecting the movable portion (220, 320, 420) to the support (6), The system includes a control circuit (13) that can be connected to the actuator (11) for applying an electrical control signal between the fixed portion (210, 310, 410) and the movable portion (220, 320, 420), The electrical control signal alternates between a maximum voltage value (Vmax) and a minimum voltage value (Vmin), and as the electrical control signal transitions from the minimum voltage value (Vmin) to the maximum voltage value (Vmax), the electrostatic force generated between the movable part (220, 320, 420) and the fixed part (210, 310, 410) causes the movable part (220, 320, 420) to move in a first direction relative to the fixed part (210, 310, 410), and the movable part ( The movement of the 220, 320, 420) causes elastic deformation of the suspension (230, 330, 430), and when the electrical control signal transitions from a first threshold voltage value (Vfin) to a second threshold voltage value (Vdebut), the elastic restoring force generated by the elastically deformed suspension (230, 330, 430) resists the electrostatic force, resulting in the movable part (220, 320, 420) moving in a second direction opposite to the first direction relative to the fixed part (210, 310, 410). During the transition from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), the voltage value of the electrical control signal decreases monotonically from the maximum voltage value (Vmax) to the minimum voltage value (Vmin), and during that time, The first average slope between the maximum voltage value (Vmax) and the first threshold voltage value (Vfin), A second mean slope between the first threshold voltage value (Vfin) and the second threshold voltage value (Vdebut), having an absolute value smaller than the first mean slope, The system has a third average gradient between the second threshold voltage value (Vdebut) and the minimum voltage value (Vmin), the third average gradient having a larger absolute value than the second average gradient, The average gradient of the above 2 is, The electrical control signal is selected to transition from the first threshold voltage value (Vfin) to the second threshold voltage value (Vdebut) within a time period that falls within a range of 0.7 to 1.3 times one natural period of the free vibration of the movable parts (220, 320, 420) relative to the fixed parts (210, 310, 410). device.

10. During the transition from the minimum voltage value (Vmin) to the maximum voltage value (Vmax), the voltage value of the electrical control signal increases monotonically from the minimum voltage value (Vmin) to the maximum voltage value (Vmax), and during that time, The fourth average slope between the minimum voltage value (Vmin) and the second threshold voltage value (Vdebut), A fifth mean slope between the second threshold voltage value (Vdebut) and the first threshold voltage value (Vfin), the absolute value of which is smaller than the fourth mean slope, A sixth average gradient, having a larger absolute value than the fifth average gradient, is continuously present between the first threshold voltage value (Vfin) and the maximum voltage value (Vmax). The device according to any one of claims 7 to 9.

11. As the electrical control signal transitions from the second threshold voltage value (Vdebut) to the first threshold voltage value (Vfin), the electrostatic force generated between the movable parts (220, 320, 420) and the fixed parts (210, 310, 410) causes the movable parts (220, 320, 420) to move in the first direction relative to the fixed parts (210, 310, 410). The device according to any one of claims 7 to 9.

12. The second threshold voltage value (Vdebut) is, If the electrical control signal takes a voltage value smaller than the second threshold voltage value (Vdebut), the electrostatic force generated between the movable parts (220, 320, 420) and the fixed parts (210, 310, 410) is selected to be insufficient to move the movable parts (220, 320, 420) relative to the fixed parts (210, 310, 410). If the electrical control signal takes a voltage value greater than the second threshold voltage value (Vdebut), the electrostatic force generated between the movable parts (220, 320, 420) and the fixed parts (210, 310, 410) is selected to be sufficient to move the movable parts (220, 320, 420) relative to the fixed parts (210, 310, 410). The device according to any one of claims 7 to 9.

13. The device according to any one of claims 7 to 9, wherein the micro-electromechanical system (10) comprises a gear (12) that can be rotationally driven by the actuator (11) relative to the support (6) around a rotation axis.

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