Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/16—Rectilinearly-movable armatures
  • H01F7/1638—Armatures not entering the winding
  • H01F7/1646—Armatures or stationary parts of magnetic circuit having permanent magnet
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H50/00—Details of electromagnetic relays
  • H01H50/005—Details of electromagnetic relays using micromechanics
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/121—Guiding or setting position of armatures, e.g. retaining armatures in their end position
  • H01F7/122—Guiding or setting position of armatures, e.g. retaining armatures in their end position by permanent magnets
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/121—Guiding or setting position of armatures, e.g. retaining armatures in their end position
  • H01F7/124—Guiding or setting position of armatures, e.g. retaining armatures in their end position by mechanical latch, e.g. detent
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H37/00—Thermally-actuated switches
  • H01H2037/008—Micromechanical switches operated thermally
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H3/00—Mechanisms for operating contacts
  • H01H3/22—Power arrangements internal to the switch for operating the driving mechanism
  • H01H3/24—Power arrangements internal to the switch for operating the driving mechanism using pneumatic or hydraulic actuator
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H37/00—Thermally-actuated switches
  • H01H37/02—Details
  • H01H37/32—Thermally-sensitive members
  • H01H37/58—Thermally-sensitive members actuated due to thermally controlled change of magnetic permeability
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H51/00—Electromagnetic relays
  • H01H51/22—Polarised relays
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H67/00—Electrically-operated selector switches
  • H01H67/22—Switches without multi-position wipers

Definitions

• the present invention relates to a magnetic actuator and in particular a magnetic microactuator which can be produced by techniques of microtechnology, that is to say micro-machining techniques used in microelectronics.
• Such an actuator can be used in various systems, for example, as an electrical microrelay for controlling the opening, closing or switching of an electrical contact, for example for controlling transistors, as an optical microrelay for controlling the passage, closure, switching or switching of an optical ray, as a micro valve or micro valve for controlling the passage, closure or switching of a fluid, as a shock sensor or displacement, as a micro pump, as a positioner for magnetic or optical heads, to perform AFM (acronym for Atomic Force Microscope or atomic force microscope) or thermal recording in positioning tables .
• AFM Atomic Force Microscope or atomic force microscope
• Electrostatic actuators are currently the most studied.
• the Lucent company markets an optical multiplexer known under the name of "lambda router” comprising electrostatic actuators. It is capable of directing an optical beam coming from an optical fiber towards another optical fiber chosen from a group of optical fibers. Its principle is based on the displacement of micro mirrors in pivot connection with a substrate. This multiplexer has a relatively slow switching time.
• such actuators pose a significant problem of electrical supply. In fact, they must be supplied with voltages of several tens or even hundreds of volts. It is therefore necessary to add to them a specific power supply which poses problem in autonomous applications. Another drawback is that the movements remain limited in relation to the size of the object.
• the mobile magnetic part is mechanically connected to the fixed magnetic part.
• This mechanical connection is difficult to achieve by collective manufacturing techniques.
• this connection limits the mobility of the mobile magnetic part, this mobility results from a deformation of one of the elements connecting the mobile part to the fixed part. This deformation can induce, during movement, fatigue of the element connecting the mobile magnetic part to the fixed magnetic part.
• the speed performance of such magnetic actuators is poor.
• the driving forces of the moving magnetic part are due to the magnetic field created by at least one coil.
• a microbool creates a much weaker force than a coil of the same shape but larger. The performance of such actuators therefore remains poor.
• the mass forces which they are capable of providing are small relative to their size.
• such actuators must be electrically powered when they are in the working position. In the absence of power, they return to the rest position. Their electrical consumption is not negligible.
• the object of the present invention is precisely to propose a magnetic actuator which does not have the drawbacks mentioned above.
• This actuator uses the principle of magnetic guidance of a mobile magnetic part, that is to say movement without mechanical contact other than that of ambient air, when it is used in air.
• the magnetic actuator of the present invention is particularly suitable for an embodiment in microtechnology.
• the present invention is a magnetic actuator comprising a movable magnetic part, a fixed magnetic part and means for triggering the displacement of the part.
• magnetic moving relative to the fixed magnetic part It comprises at least two non-magnetic supports placed in different planes, delimiting between them a space, the fixed magnetic part being integral with at least one of the supports, the supports each having a stop zone for the mobile magnetic part, the zone of stop and the fixed magnetic part being separate.
• the movable magnetic part is levitated in the space between the two supports thanks to a magnetic guide due to the fixed magnetic part when it is not in abutment against the abutment zone of one of the supports, the magnetic part mobile is likely to take several stable magnetic positions and in these positions it abuts against a support.
• stable magnetic position is meant a stable position in which there is a magnetic interaction between the mobile magnetic part and the fixed magnetic part and which does not require an electrical supply to maintain this position.
• the mobile magnetic part is not mechanically connected to the fixed magnetic part and there is no mechanical guide between the mobile magnetic part and the fixed magnetic part.
• the mobile magnetic part comprises a magnet.
• the fixed magnetic part can comprise at least one magnetic part.
• the magnetic piece can be a magnet. It can be thermomagnetic.
• the fixed magnetic part can comprise at least one pair of magnetic parts on a support.
• the interaction between the fixed magnetic part and the mobile magnetic part realizes the centering of the mobile magnetic part on the stop zone, but this centering can be reinforced.
• the mobile magnetic part and at least one of the supports can comprise means for mechanically centering the mobile magnetic part on the abutment zone of said support.
• the magnetic centering means can be substantially bevelled or chamfered reliefs carried both by the support and the movable magnetic part, these reliefs having conjugate shapes.
• the fixed magnetic part contributes to delimiting at least one of the stop zones.
• the means for triggering the displacement of the mobile magnetic part can be carried by at least one of the supports.
• They can have a magnetic effect.
• the means for triggering the displacement of the mobile magnetic part can heat the fixed magnetic part and modify its magnetic properties.
• the means for triggering the displacement of the mobile magnetic part can create a magnetic field in the vicinity of the mobile magnetic part.
• they can be carried out by at least one driver capable of be traversed by an electric current.
• the energy consumption is zero when the mobile magnetic part is in abutment against one of the non-magnetic supports, that is to say in the working position.
• the magnetic actuator can then be used as a positioner.
• the means for triggering the displacement of the mobile magnetic part can be pneumatic or hydraulic means.
• the fixed magnetic part can be made of a material chosen from the group of soft magnetic materials, hard magnetic materials, hysteresis materials, superconductive materials, diamagnetic materials, these materials being taken alone or in combination.
• the supports can be made from semiconductor material, dielectric material or conductive material, these materials being taken alone or in combination.
• At least one zone of stop comprises a pair of electrical contacts and the movable magnetic part comprises at least one electrical contact, the movable magnetic part coming to connect the two electrical contacts of the pair of electrical contacts, when it is in abutment against the stop zone.
• At least one of the supports has, in the abutment zone, an opening for the passage of a fluid.
• the mobile magnetic part includes a mirror intended to pass through a slot in one of the supports.
• the present invention also relates to a matrix of magnetic actuators, it comprises a plurality of magnetic actuators thus characterized, these magnetic actuators sharing at least one and the same support.
• the present invention also relates to a method for producing a magnetic actuator.
• It comprises the following stages: on a first non-magnetic substrate production of a sacrificial frame along the contour of a base of a mobile magnetic part, deposition of a first dielectric layer on the first substrate and production of at least one box suitable for receiving a fixed magnetic part, deposit in the box of the fixed magnetic part, deposition of a second dielectric layer on the first dielectric layer and production of boxes able to receive the mobile magnetic part and at least one conductor of means for triggering the displacement of the mobile magnetic part, deposit in the boxes of the mobile magnetic part and of the conductor, etching in the dielectric layers of one or more trenches reaching the sacrificial frame, assembly of the first substrate turned over on a second non-magnetic substrate so as to delimit a space between the two substrates, this space being intended for the displacement of the magnetic part mobile, etching of the first substrate and removal of the sacrificial frame to release the mobile magnetic part and the base.
• the method may include a step of inserting at least one spacer between the first and the second substrate at the time of assembly.
• the space can be formed by balls of fusible material, inserted between the first and the second substrate at the time of assembly and an annealing of said balls after assembly.
• the method can comprise, before the assembly of the two substrates, the following steps: production on the second substrate, in a first dielectric layer, of at least one box capable of receiving the fixed magnetic part, depositing in the box of the part fixed magnetic, deposition of a second dielectric layer on the first dielectric layer and production of at least one box capable of receiving at least one conductor of the means for triggering the displacement of the mobile magnetic part, deposit in the box of the conductor.
• the method may include a step of magnetizing the mobile magnetic part and possibly the fixed magnetic part before the step of releasing the mobile magnetic part.
• the first substrate is thinned before the etching step of the first substrate, the etched part having a mirror function.
• the first substrate and the second substrate can be made from semiconductor material or dielectric material.
• Figures 1A, 1B show in two stable positions a magnetic actuator according to the invention operating as a valve;
• Figure 2 shows a magnetic actuator according to the invention operating as a valve;
• FIGS. 4A, 4B, 4C show respectively, a magnetic actuator according to the invention operating as an electrical relay, as an electrical switch, and a top view of the upper windings of the means for triggering the displacement of the mobile magnetic part;
• FIGS. 5A and 5B show, in two different positions, a magnetic actuator operating as an optical relay;
• FIGS. 6A, 6B show two magnetic actuators according to the invention, the fixed magnetic parts of which are formed from a single magnetic piece per support;
• Figure 7 shows a magnetic actuator according to the invention operating as a positioner;
• FIGS. 8A, 8B show magnetic actuators according to the invention arranged in a matrix and sharing at least one and the same support;
• FIG. 9A shows a magnetic actuator according to the invention;
• FIG. 9B is a flow chart making it possible to explain how to position the magnets of the actuator of FIG.
• FIG. 9D shows the force Fx which applies to the movable magnetic part, in abutment, as a function of its position along the axis x when the actuator has a configuration to be avoided with two unstable positions in abutment;
• FIG. 10A to 1011 and 1012 show an embodiment of the first support, the movable magnetic part, a pair of magnets and a pair of conductors of a magnetic actuator according to the invention
• FIG. 11A to 11D1 and 11D2 show an embodiment of the second support, a pair of magnets and a pair of conductors of a magnetic actuator according to the invention
• FIGS 12A1, 12A2, 12B1, 12B2 show the steps of assembling the two supports and releasing the movable magnetic part
• Figures 13A, 13B show the step of assembling the first support of Figures 10 with a second support without magnet or conductor and the step of releasing the movable magnetic part.
• FIGS. 1A, 1B schematically show an example of a magnetic actuator according to the invention in two stable positions, in abutment, different.
• the actuator is a valve.
• This actuator comprises a first support 1 and a second non-magnetic support 2, arranged in strata in different planes, and delimiting between them a space 3 in which a movable magnetic part 4 is capable of moving.
• the supports are represented by form of plates arranged substantially parallel, one above the other, the first support 1 being at the top and the second support 2 at the bottom.
• the supports 1, 2 can be produced for example based on semiconductor material such as silicon or gallium arsenide, dielectric material such as ceramic, glass, or a plastic material, conductive material such as l 'aluminum. Combinations of several of these materials are possible. However, the supports 1, 2 are preferably electrically insulating, at least locally, insofar as they carry both magnetic parts and electrical conductors.
• This actuator also comprises a fixed magnetic part 5 secured to at least one of the supports 1, 2.
• the fixed magnetic part 5 is formed of two magnetic parts 51, 52 which are secured to the first support 1. These magnetic pieces can be magnets but it is not an obligation. It is assumed in the rest of the description that these are magnets unless otherwise stated. They are placed on one of its main faces, that which is opposite the space 3.
• the second support 2 does not carry a fixed magnetic part.
• the magnetic parts could be integral with its other main face, on the side of the space 3 as are the magnets 51, 52 shown in FIGS. 5A, 5B described later.
• the magnets 51, 52 are included in the support 1, they are embedded there.
• the fixed magnetic part 5 associated with one of the supports and that the mobile magnetic part 4, in abutment be offset, that is to say in different planes. If, however, the fixed magnetic part is on the side of the space 3, the magnets of the fixed magnetic part and the mobile magnetic part will preferably be given different thicknesses to obtain this offset.
• the mobile magnet will be thicker than the fixed magnet (s).
• the mobile magnetic part 4 comprises a magnet 40. It has no mechanical connection with the fixed magnetic part 5.
• the non-magnetic supports 1, 2 each have a stop zone 10, 20 for the mobile magnetic part 4.
• the fixed magnetic part 5 contributes to delimiting the stop zones 10, 20.
• the two magnets 51, 52 are located on either side of the stop zone 10. In all cases the stop zone 10, 11 and the fixed magnetic part 5 are distinct but adjacent so that the interaction can take place.
• the stop zone 20 of the second support 2 is opposite the stop zone 10 of the first support 1.
• the mobile magnetic part 4 is either in abutment against one of the supports 1, 2, or in levitation in space 3 between the two supports 1, 2, without any contact, magnetically guided by the fixed magnetic part 5 at least.
• the magnetic actuator also comprises means 6 for triggering the movement of the mobile magnetic part 4.
• the means 6 for triggering the movement of the mobile magnetic part 4 have the function of modifying the forces which interact on the mobile magnetic part 4 and therefore to modify the balance of the fixed magnetic part-mobile magnetic part assembly. They initiate the displacement of the mobile magnetic part • 4. Then the displacement is due to the interactions between the fixed magnetic part 5 and the mobile magnetic part 4. It is assumed that in this example, the means
• the first support 1 is provided with an orifice 7 located in the stop zone 10. It is sought that in a stable magnetic position the movable magnetic part 4 comes to be pressed in the stop zone 10 against the first support 1 thanks to the interaction exerted on it by the fixed magnetic part 5. It then closes the orifice 7. None can penetrate into space 3 through the orifice 7.
• a fluid f is injected through the orifice 7 towards the space 3 and that it has sufficient pressure to move the mobile magnetic part 4, the latter comes to be placed in the abutment zone 20 pressed against the second support 2 (FIG. 1A). The fluid f can then enter the space 3 and flow laterally according to the dotted arrows.
• the mobile magnetic part 4 In this position in abutment against the second support 2, the mobile magnetic part 4 remains in interaction with the fixed magnetic part 5. If the pressure of the fluid f is no longer exerted sufficiently or the pressure of the fluid f is reversed, the mobile magnetic part 4 returns to the high position, in abutment against the first support 1 and it closes the orifice 7 (FIG. 1B). This occurs when the geometric characteristics of the magnets, their magnetization and their relative positions in space are adjusted correctly.
• the interaction between the fixed magnetic part and the mobile magnetic part has the effect of centering the mobile magnetic part in the stop zone.
• mechanical centering means 8 of the mobile magnetic part 4 can be provided at the stop zone 10, 20 of at least one of the supports 1, 2.
• the mobile magnetic part 4 and the abutment zone 10 concerned can each be provided with a relief 80, 81, these reliefs 80, 81 having conjugate shapes. These reliefs can be chamfered or bevelled parts, they are then substantially pyramidal or conical. These reliefs 80, 81 cooperate when the movable magnetic part 4 is in abutment against the support 1, 2, it comes to be embedded in the support.
• the embedding means are located on the first support 1.
• the displacement of the movable magnetic part 4 can then take place from a perfectly centered high position to a low position and vice versa.
• the sides of the movable magnet 40 which are substantially pyramidal and the support 1 which carries the orifice 7 comprises a bowl whose sides are also substantially pyramidal, the movable magnet coming from place in the support bowl in the high position.
• the movable magnet be carried by a base and that it is this base which comprises the centering means.
• These reliefs can easily be produced by chemical machining, in particular when techniques used in microelectronics are used to produce the magnetic actuator.
• the centering means 8 also have a fluid tightness function when the movable magnetic part 4 is in the high position. The fluid cannot be introduced into space 3 until its pressure is not sufficient.
• the fixed magnetic part 5 is distributed over the two supports 1, 2. It comprises two pairs of magnets respectively referenced 51, 52, 53, 54 and each pair of magnets is integral with one of the supports 1 , 2.
• the fixed magnetic part 5 By distributing the fixed magnetic part 5 over the two supports 1, 2, it is easier to control the positioning of the mobile magnetic part 4 in abutment. More generally, the magnetic pieces, grouped in pairs, are located on either side of a stop zone.
• the mobile magnetic part 4 is capable of assuming several stable magnetic positions, in each of these positions it is in abutment against a support 1,2. These stable magnetic positions do not require a power supply, the mobile magnetic part is in magnetic interaction with the fixed magnetic part 5.
• FIG. 2 shows that the magnets 51 to 54 of the fixed magnetic part 5 are each equipped, on one of their faces, with a heating resistor R.
• These resistors can be produced by a conductive metallic deposit, for example based on copper , gold silver, aluminum, polysilicon.
• the means 6 for triggering the displacement of the mobile magnetic part 4 are distributed over the two supports 1, 2. It could be envisaged that they are located on one of them only as in FIG. 4A.
• a fixed magnetic part 51 to 54 provided with such resistors R is made of a thermomagnetic material whose magnetic properties depend on the temperature.
• a thermomagnetic material whose magnetic properties depend on the temperature.
• this material is magnetic for a temperature below its Curie point and non-magnetic for a higher temperature. It is also possible to use a material whose ferromagnetism properties are obtained above a so-called transition temperature.
• the heating must not disturb the magnetic properties of the mobile magnetic part 4.
• the magnet 40 of the mobile magnetic part 4 in a material whose Curie point is greater than that of the magnets 51, 52 of the fixed magnetic part 5 or else thermally insulate it from the fixed magnetic part 5.
• a resistance R instead of heating by a resistance R , one can consider coming to irradiate the fixed magnetic part 5 with an optical beam (for example laser or infrared diode) aimed at heating it. It is also possible to make a current flow directly in the fixed magnetic part 5 to heat it.
• the heating can be interrupted, there is no more energy consumption.
• the energy consumption is also zero.
• the magnetic actuator is a micro-valve.
• Each of the supports 1, 2 has an orifice 7 intended to let a fluid f 1, f 2 penetrate into or leave the space 3 between the two supports 1, 2.
• the mobile magnetic part 4 only one of the fluids fl or f2 can enter or leave space 3. The magnetic part prevents the penetration of the other fluid.
• Figure 3 shows, in top view, the magnetic field lines which are established around the magnet 40 of the movable magnetic part 4 whose direction of magnetization is shown diagrammatically by an arrow. It is assumed that the magnet 4 is in abutment on the second support 2. It has, in this example, a shape of a rectangular parallelepiped and its poles are located at the ends of its long sides.
• the means 6 for triggering the displacement of the mobile magnetic part 4 are formed by two separate conductors 61, 62, each surrounding a pole of the magnet 40. Arrows show the direction of flow of the current I in the conductors 61, 62, so that a force is applied to the magnet 40 aimed at detaching it from the second support 2.
• each at one end of the magnet 40 one could have used one or more loop conductors, with one or more turns, to obtain this same current flow. It is assumed that this is the case in FIGS. 4B, 4C with a pair of coils (610, 620), (630, 640) integral with each of the supports 1, 2.
• FIGS. 4B, 4C with a pair of coils (610, 620), (630, 640) integral with each of the supports 1, 2.
• an efficiency maximum is obtained when each pole of the magnet 40 is bordered by a conductor substantially in a semicircle.
• the conductor can be made just like the resistance by deposition based on conductive metal.
• the magnetic actuator of FIG. 4A is an electrical relay.
• One of the supports 1, 2 comprises, in the abutment zone 10, a pair of electrical contacts C1, C2 isolated from one another.
• the mobile magnetic part 4 has an electrical contact C which electrically connects the two electrical contacts Cl, C2 of the pair when the mobile magnetic part 4 is in abutment against the support 1 thus equipped.
• the pair of electrical contacts C1, C2 is included in an electrical circuit (not shown) which is closed when the mobile magnetic part 4 is in abutment against the support 1 thus equipped and open when the mobile magnetic part 4 is in abutment against the other support 2.
• the other support 2 does not have a fixed magnetic part, nor means for triggering the displacement of the mobile magnetic part 4. It is possible, as in FIG. 4B, to place a pair of electrical contacts C1, C2 on each of the supports 1, 2 and equip the two main faces of the mobile magnetic part 4 with an electrical contact C. Depending on its position, the mobile magnetic part 4 closes the electrical circuit from above or from below.
• FIG. 4C a diagrammatic view from above is shown, the pair of coils 610, 620 and the pair of magnets 51, 52 secured to the first support 1 and the mobile magnetic part 4.
• FIGS. 5A, 5B now show a magnetic actuator having the function of an optical relay or switch respectively in the levitation position and in the stable working position.
• the mobile magnetic part 4 is provided with a mirror 50.
• the mirror 50 When the mobile magnetic part 4 is in abutment on the second support 2, the mirror 50 is confined in the space 3 between the two supports 1, 2.
• the mirror 50 passes through a slot 501 carried by the first support 1 and leaves the space 3, it arises on the other side of the first support 1.
• This mirror 50 when '' it is in the high position can then deflect an optical beam which is not deflected when the mirror is in the low position.
• the optical beam is not shown so as not to overload the figures.
• the supports 1, 2 each receive a single fixed magnetic part 51, 51, instead of several in the previous examples.
• This magnetic piece can completely or partially surround the abutment area of the support. Only one of the supports could have been fitted with such a magnetic piece.
• FIG. 6A which is a section, there are two magnetic parts 51, 53 substantially in the form of a ring. Each magnetic part surrounds a stop zone 10, 20. Another difference compared to what has been described previously is that the mobile magnetic part 4 is now substantially cylindrical.
• the means 6 for triggering the displacement of the mobile magnetic part 4 take, in the example of FIG. 6A, the shape of a coil whose winding axis is parallel to that of the mobile magnetic part 4.
• the direction d magnetization of the fixed and movable magnetic parts is the same, but instead of being in the plane of the supports 1, 2 substantially perpendicular to the movement as in the examples above, it is substantially perpendicular to the plane of the supports and substantially parallel to the displacement.
• the fixed magnetic parts 51, 53 are embedded in the supports 1, 2 and in the abutment zones 10, 20, the supports are thinned.
• a magnetic part 51 is substantially U-shaped, secured to the support 1. It is embedded on the side of its upper face.
• Another magnetic piece 53 is integral with the other support 2. It is assumed that it is also substantially U-shaped. This second magnetic piece 53 could have been omitted.
• one of the supports 1, 2 is thinned at the level of a stop zone 10.
• the means 6 for triggering the displacement of the mobile magnetic part 4 are integral with the support 1.
• the magnetic actuator according to the invention can have a positioner function.
• the means 6 for triggering the displacement of the mobile magnetic part then also serve to maintain the mobile magnetic part 4 in a fixed position in levitation.
• the current can be controlled as a function of the position of the mobile magnetic part 4.
• FIG. 7 illustrates this variant.
• the signal delivered by this device is compared to a setpoint K in a comparator 66 and the result of the comparison is used to control a power source 67 provided for supply the conductors 61 to 64.
• the device 65 which detects the position of the mobile magnetic part 4 can take the form of two capacitive sensors 65.1, 65.2 each located on one of the supports 1, 2. They measure the capacities between the support concerned 1, 2 and the mobile magnetic part 4.
• a differentiating device 65.3 receives the signals coming from the two capacitive sensors 65.1, 65.2, makes the difference and delivers the signal representative of the position of the mobile magnetic part 4 to the comparator 66 .
• soft magnetic materials such as iron, nickel, iron-nickel alloys, iron-cobalt, iron-silicon, magnetize according to an inductive field to which they are subjected.
• Hard magnetic materials correspond to magnets such as ferrite magnets, samarium-cobalt magnets, neodymium-iron-boron magnets, platinum-cobalt magnets. Their magnetization depends little on the external magnetic field.
• Hysteresis materials for example of the aluminum-nickel-cobalt (AlNiCo) type, have properties which lie between those of soft magnetic materials and those of hard magnetic materials. They are sensitive to the magnetic field in which they are found. As for diamagnetic materials such as bismuth or pyrolitic graphite, their magnetization is collinear with the inductive magnetic field but in the opposite direction.
• the superconductive materials could be alloys nobium-titanium (NbTi), yttrium-barium-copper-oxygen (YBaCuO) for example. 04/015725
• the mobile magnetic part 4 can be made, for example, of ferrite, samarium-cobalt, neodymium-iron-boron, platinum-cobalt.
• Magnetic point materials. Low curie which are suitable for producing the fixed magnetic part 5 are for example the manganese-arsenic alloys
• FeAs cobalt-manganese-phosphorus
• CoMnP cobalt-manganese-phosphorus
• ErFeB erbium-fer-boron
• FeRh Iron-rhodium alloys
• the different actuators are optical relays like those in FIGS. 5A, 5B, they are arranged in a matrix M and their first support 1 is common to all. An optical multiplexer is thus obtained.
• the magnetic actuators are only visible by their mirror 50 when it emerges from the space between the two supports, otherwise their position is materialized by the slot 501. They are at the crossroads between n conductors of columns il to i5 and m conductors of lines jl to j5 (n and m- are integers, n and m can be different or not).
• signals propagating on a sheet formed by the n conductors of columns 11 to 15 can be switched to the m conductors of lines j 1, j 2, j 3, d4, d5.
• These signals can be electrical or optical signals depending on the nature of the actuators.
• the row and column conductors can be electrical conductors, optical fibers or simply optical beams. Due to the bistability of the actuators of the matrix M, the latter can be programmed and keep its configuration without it being necessary to supply it electrically.
• the actuators A can be grouped into a particular matrix B as in FIG. 8B with a row conductor il and several column conductors j 1 to j3.
• the signals it carries can be directed to the different column conductors jl to j3 depending on the state of the different actuators A. It is assumed that in this configuration the actuators are electrical relays like the one in Figure 4A.
• FIG. 9A A minimum value of the force Fz which is applied to the mobile magnetic part 4 to keep it pressed against one of the supports 1, 2 is imposed so that the actuator can have, for example, sufficient impact resistance .
• Fz force which is applied to the mobile magnetic part 4 to keep it pressed against one of the supports 1, 2
• the actuator can have, for example, sufficient impact resistance .
• the x, y and z axes are shown in the figure.
• the mobile magnetic part 4 must oppose this displacement and resume its stable magnetic position and centered in the abutment zone 10, 20.
• the mobile magnetic part must have a good lateral stability in high or low position.
• the inventors have realized that for a fixed magnetic part 5 and a mobile magnetic part 4 of given characteristics, for a force Fz holding against one of the given supports 1, 2, to obtain this stable and centered magnetic position, it was necessary adjust correctly, both the interval sep separating, according to x, the fixed magnetic part from the mobile magnetic part and the gapz separating, according to z, the fixed magnetic part 4 from the mobile magnetic part 5, when the magnetic part mobile is in abutment against support 1.
• the fixed magnetic part 5 is distributed over the two supports and that it comprises two pairs of identical magnets (51, 52), (53, 54).
• the mobile magnetic part 4 includes a magnet 40. It is assumed for simplicity that the magnetization directions of all the magnets are collinear and in the same direction. It is of course possible that this is not not the case but the positioning of the magnets becomes more complicated.
• the means for triggering the displacement of the movable magnet are not shown so as not to overload the figure.
• the force Fz is not in the imposed range, one modifies sep and / or gapz and / or the geometrical characteristics of the magnets and / or their magnetization to adjust its value. The more we decrease gapz and sep the more the force Fz increases.
• the two fixed magnets can be brought together and / or reduced the thickness of the support 1 since, in this example, the fixed magnets 51, 52 are placed on one side of the support 1 and the movable magnet 40 in abutment on the other side of the support 1. On the contrary, the thickening of the support 1 reduces the force Fz.
• the magnets 53, 54 of the other pair will be arranged with the same intervals sep and gapz. It can be imposed that the value of the holding force Fz is different from one support • to another. The same calculations are repeated to position the other pair of fixed magnets 53, 54 relative to the movable magnet 40 to obtain a suitable force Fz and the conditions of stability, when the movable magnet 40 is in abutment on 1 ' other support 2. 04/015725
• Gapz + h greater than D.sep with h height of the fixed and mobile magnets and D between 1 and 1.5.
• Figures 9C, 9D show variations in the force Fx as a function of x when the actuator has the desired stable magnetic position and when it does not.
• the fixed magnetic part 5 of the actuator comprises two pairs of magnets (51, 52), (53, 54), one secured to the first support 1 and the other secured to the second support 2.
• the mobile magnetic part 4 of the actuator comprises a magnet 40 integral with one face of a base 41, this base 41 carries on its other face a mirror 50.
• the means 6 for triggering the displacement of the mobile magnetic part 4 are produced by two pairs of conductors (61, 62), (63, 64), each pair being integral with one of the supports 1, 2.
• the advantages of this process is that it can be produced several at the same time, they all share at least one common support.
• first non-magnetic substrate 90 for example of semiconductor material such as silicon or gallium arsenide (FIG. 10A).
• This first substrate 90 after treatment will lead to the first non-magnetic support 1, that of the top.
• a sacrificial layer 91 for example made of titanium, is deposited on the silicon. This sacrificial layer 91 will serve to delimit the base 41 of the mobile magnetic part 40. It is etched so as to leave only a frame 910 along the perimeter of the base. ( Figure 10B).
• This frame 910 is hereinafter called the sacrificial frame.
• a first dielectric layer 92 for example made of silicon oxide, is used on the first substrate 90, above the sacrificial frame 910, which will be used to produce one of the pairs of magnets 51, 52 of the fixed magnetic part. 5 ( Figure 10C). This first dielectric layer 92 is then planarized.
• the geometry of the pair of magnets 51, 52 is delimited by photolithography.
• a resin (not referenced) is used.
• boxes 93 are etched for the pair of magnets 51, 52 (FIG. 10D). The boxes are located on either side of the sacrificial frame 910. The etching can be a dry etching. The etching stops on the first substrate 90. The resin is removed.
• the magnets 51, 52 are deposited in the boxes 93
• a second dielectric layer 94 for example made of silicon oxide in which the pair of conductors and the magnet of the movable magnetic part will be found (FIG. 10F).
• a resin is used for this (not shown).
• a box 95 is etched in the second dielectric layer 94 for the magnet of the fixed magnetic part and of the boxes 96 for the conductors of the pair (FIGS. 10G1 and 10G2) and of the boxes 96.1 for the studs which terminate them (FIG. 10G2).
• the boxes 96 for the conductors are located on either side of the box 95 for the magnet of the mobile magnetic part.
• the boxes 96 for the conductors are located substantially above the magnets 51, 52 of the pair.
• the etching can be a dry etching.
• the boxes 96.1 for the studs are on both sides of the boxes 96 for the conductors.
• the magnet 40 of the movable magnetic part is deposited in the appropriate box 95. We end with a planarization step of the magnet 40 ( Figure 10H1 and Figure 10H2).
• the conductors 61, 62 are deposited in the appropriate boxes 96 and the pads 62.1, 62.2 in the boxes 96.1. We end with a planarization step of the conductors 61, 62 and the studs 61.1, 62.1. This deposition can be done electrolytically with copper ( Figure 1011 and Figure 1012).
• One or more trenches 97 are etched in the two dielectric layers 92, 94 until reaching the sacrificial frame 910. These trenches delimit the sides of the base of the movable magnet 40 (FIG. 1011 and FIG. 1012). This engraving can be a chemical attack. These trenches 97 can configure the sides of the base with the reliefs of the centering means.
• a second non-magnetic substrate 100 made of semiconductor material, such as silicon, covered with a first dielectric layer 101, for example made of silicon oxide.
• This second substrate 100 after treatment will lead to the second non-magnetic support 2 that at the bottom.
• One can for example use a solid silicon substrate which is oxidized or directly use an SOI substrate.
• boxes 102 are etched to receive the other pair of magnets of the fixed magnetic part (FIG. 11A).
• the second pair of magnets 53, 54 is deposited in the same way as the first pair. We end with a planarization step of the magnets ( Figure 11B).
• a second dielectric layer 103 for example made of silicon oxide, is then deposited on the first layer 101, this second dielectric layer 103 having to receive the conductors of the second pair of conductors.
• boxes 104 are engraved for the conductors of the second pair of conductors
• the first substrate 90 as obtained in FIG. 1011, can then be assembled, by turning it over, to the second substrate 100 as obtained in FIG. 11D1, by inserting between the two dielectric spacers 110 which contribute to delimiting a space 3 in which the mobile magnetic part will be able to move (FIG. 12A1).
• the dielectric layers 92, 94 and 101, 103 face each other while the semiconductor substrates 90, 100 are opposite. It is arranged so that the magnets 51, 52 and 53, 54 of the two pairs are aligned in pairs and so that the conductors 61, 62 and 63, 64 of the two pairs are aligned in pairs.
• the first substrate 90 as obtained in FIG. 1012 can be assembled, by turning it over, to the second substrate 100 as obtained in FIG. 11D2, by inserting balls 112 of fusible material between the two.
• These fusible balls 112 are then annealed. They help to delimit the space 3 in which the mobile magnetic part will be able to move (FIG. 12A2). They also make it possible to establish an electrical contact between the conductors 62, 61 of the substrate 90 and the conductors 63, 64 of the substrate 100 via the pads 62.1, 61.1 and 63.1, 64.1.
• the magnets of the two pairs are aligned two by two, the conductors of the two pairs and the studs being also aligned two by two.
• This first semiconductor substrate 90 makes it possible to produce the mirror 50. Its thickness, which can be adjusted, will correspond to the height of the mirror 50.
• An etching of one or more trenches 111 is carried out in the first semi-substrate 90 conductor to delimit the sides of the mirror 50 and form the slot in which it will slide when the movable magnetic part is pressed against the first support. This etching stops on the first dielectric layer 92.
• the sacrificial frame 910 is then removed by etching, which leads to freeing the base 41 of the movable magnet 40 and of the mirror 50 (FIGS. 12B1 and 12B2).
• a thinning of the first substrate is carried out so that the mirror in the high position protrudes above the substrate which surrounds it and that it is hidden in the low position.
• the magnet 40 and its base 41 are able to move in space 3.
• the magnets 40, 51 to 54 are magnetized properly because otherwise there would be no suitable interaction between the movable magnet 40 and the pairs of magnets 51, 52 and 53, 54 of the fixed magnetic part 5. If intervention is required, the magnetization can be done by circulating a current in the conductors 61 to 64.
• FIGS. 10 are carried out on the first substrate but not the steps of FIGS. 11.
• a second dielectric non-magnetic substrate 120 for example made of silicon oxide, by inserting between the two spacers 110 (FIG. 13A).
• conductive balls we could insert conductive balls but it is not shown so as not to multiply the number of figures.
• the mirror 50 and the release of the mobile magnetic part 4 would be produced as described previously in FIGS. 12B1 and 12B2 (FIG. 13B).
• the magnetic actuator according to the invention if it occupies a volume greater than about one cubic centimeter, risks being sensitive to the external environment such as vibrations or shocks. Its performance may not be optimal in such disturbed environments. However, against all expectations, with smaller dimensions, its performance is greatly improved whatever the environment.
• the interaction between the movable magnetic part and the fixed magnetic part is favorable and does not bring about a degradation of performance as in the case of a larger actuator.
• the main characteristics of an actuator according to the invention are to have a relatively high displacement speed, an ability to exert significant mass forces and significant displacements relative to its size.
• the mobile magnetic part in stable magnetic position in abutment against one of the substrates resists impact.
• the actuator consumes very little energy and only during movement of the part mobile magnetic and not in stable magnetic position when the mobile magnetic part is in abutment against one of the substrates.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Reciprocating, Oscillating Or Vibrating Motors (AREA)
• Micromachines (AREA)
• Magnetic Heads (AREA)
• Permanent Field Magnets Of Synchronous Machinery (AREA)
• Hard Magnetic Materials (AREA)
• Magnetic Treatment Devices (AREA)
• Electromagnets (AREA)

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