EP2092580A1 - Transducteur capacitif doté de zones de découpe - Google Patents

Transducteur capacitif doté de zones de découpe

Info

Publication number
EP2092580A1
EP2092580A1 EP06805548A EP06805548A EP2092580A1 EP 2092580 A1 EP2092580 A1 EP 2092580A1 EP 06805548 A EP06805548 A EP 06805548A EP 06805548 A EP06805548 A EP 06805548A EP 2092580 A1 EP2092580 A1 EP 2092580A1
Authority
EP
European Patent Office
Prior art keywords
layer
electrode
actuator
electrically conductive
cutting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP06805548A
Other languages
German (de)
English (en)
Inventor
Jorgen Mads Clausen
Peter Gravesen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Danfoss AS
Original Assignee
Danfoss AS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Danfoss AS filed Critical Danfoss AS
Publication of EP2092580A1 publication Critical patent/EP2092580A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/50—Piezoelectric or electrostrictive devices having a stacked or multilayer structure
    • H10N30/506—Piezoelectric or electrostrictive devices having a stacked or multilayer structure of cylindrical shape with stacking in radial direction, e.g. coaxial or spiral type rolls
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/08—Shaping or machining of piezoelectric or electrostrictive bodies
    • H10N30/085—Shaping or machining of piezoelectric or electrostrictive bodies by machining
    • H10N30/088—Shaping or machining of piezoelectric or electrostrictive bodies by machining by cutting or dicing
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/09—Forming piezoelectric or electrostrictive materials
    • H10N30/098—Forming organic materials
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
    • H10N30/206—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators using only longitudinal or thickness displacement, e.g. d33 or d31 type devices

Definitions

  • the present invention relates to a capacitive transducer capable of converting between electrical energy and mechanical energy. More particularly, the present invention relates to a capacitive transducer having corrugated electrodes divided into sections separated by totally or almost electrode free areas, the corrugation having been obtained without applying a pre-strain to a material holding the electrodes.
  • the capacitive transducer of the present invention is formed by rolling a web of a dielectric material holding the set of electrodes, preferable rolled at an angle.
  • Capacitive transcucers with electrodes for deflecting an elastomeric material, or elastomeric like material are known to facilitate large deformation in a relatively low electric field, e.g. when compared with alternative dielectric materials.
  • capacitive transducers are made by applying a conductive electrode, e.g. a carbon containing paint or a thin layer of gold to both sides of a film made from an elastomeric material e.g. silicone or polyurethane. The film is typically made in a moulding process.
  • Laminated actuators are known, e.g. from US 5,977,685 which discloses layers of a polyurethane elastomere with electrodes on each side. The layers are laminated together to form a deformable sheet.
  • an capacitive transducer is sometimes referred to as a Polymer Artificial Muscle (EPAM), electroactive elastomers or electroactive polymers.
  • the capacitive transducer may operate as a generator, an actuator or a sensor. In the main embodiment the capacitive transducer is operating as an actuator and is therefore in the following mainly referred to as a capacitive actuator or just actuator.
  • elastomeric sheets can be rolled to form cylindrical actuators which could replace more traditional linear actuators in small-scale systems, e.g. in robotic applications wherein the cylindrical actuators may form gripping "fingers" e.g. of a robotic wrist.
  • the film is rolled into a tubular body which is fitted with mechanical connectors at axially opposite ends. Upon application of an electrical field to the electrodes, the sheet contracts or expands axially during deformation of the elastomeric material.
  • Capacitive actuators are normally made in batches of a small number and for very specific purposes. Often, the variation between batches merely relates to the length of cylindrical actuators but due to the available manufacturing technology, such simple variations are costly and time consuming.
  • the elastomere is made in a thickness in the range of 10-100 ⁇ m, and the electrode is made in a thickness of 0,01-0,5 ⁇ m, e.g. by vaporising a thin layer of a conductive metal onto a surface of the elastomer.
  • one or both of the electrodes would normally be deformed, and short circuiting of the electrodes across the edge of the elastomer may therefore occur and render the actuator useless.
  • the invention provides an actuator comprising a cutting area, in which at most one of the top and back surfaces is provided with an electrode.
  • the actuator can be divided into several separate actuators without causing short circuiting between the top and the back electrode. Accordingly, an easier way of producing actuators in individual lengths, e.g. in accordance with specific customer demands, has been facilitated.
  • an electrode is a conductive surface portion located on one side of the elastomeric body, and which in combination with an adjacent electrode on the opposite side of the elastomeric body provides an expansion or contraction of the elastomeric body when an electrical field is applied between the electrodes.
  • the electrodes may be made from any kind of electrically conductive material, it may have any shape, and it may be provided in various thicknesses.
  • the electrode is provided with a connecting portion which facilitates application of the electrical field.
  • the electrode could be divided into a plurality of electrode fields which are electrically connected by a connector. In this context, such electrode fields and the connector are considered to represent one electrode.
  • one of the surfaces of the elastomeric body is not provided with an electrode in the cutting area, and preferably, not provided with any electrically conductive material at all.
  • the electrodes i.e. e.g. the electrode fields and a connector, could be made by painting a conductive material onto the surface of the elastomeric layer, or a strip of a conductive material could be adhesively bonded to the surface of the elastomeric material, or as will be discussed later, the connector could form part of a core around which the actuator is coiled.
  • the connector which connects the fields should be located so that it covers an area wherein the opposite surface of the first layer is uncovered by electrically conductive material.
  • the connector could be a separate connector which is arranged so that it connects the fields which constitute the electrode, or the electrode and the connector are formed as one uniform electrically conductive pattern on the surface of the first layer.
  • the electrode could have the shape of a comb or an E or similar shapes with an axially extending connector and electrode fields extending perpendicularly to the connector.
  • the connectors of the top electrode and of the back electrode should simply be located on different locations of the first layer, i.e. not directly adjacent on opposite sides of the first layer.
  • the top electrode could be rotated 180 degrees and shifted one half of the distance between each field in the direction in which the connector extends, relative to the back electrode so that the fields of the top electrode become interposed between the fields of the back electrode.
  • a cutting area is thereby formed in which at most one of the surfaces of the first layer is covered by an electrode or by a connector, and it is therefore possible to separate the actuator into several smaller actuators by cutting through the connector in the cutting area.
  • the cutting area could comprise one portion in which the top surface of the first layer is covered by the top electrode or a connector and another portion in which the back surface of the first layer is covered by the back electrode or a connector, as long as the electrically conductive material is only deposited on one of the surfaces. If the connector is deformed during the cutting process, it is not in danger of short circuiting the electrode of the opposite surface since this surface is not covered with electrically conductive material in that part of the cutting area.
  • An outer surface of the top electrode could be covered with an electrically isolating material and the actuator layer may thereafter be rolled around an axis to form a cylindrical actuator extending in a longitudinal direction.
  • the actuator could be rolled around a core of an elastomeric material, and the core may comprise a conductive surface area which constitutes the conductor that electrically connects the above-mentioned electrode fields.
  • each field may form an edge portion facing towards an adjacent field, and these edge portions may preferably extend at an angle different from 90 degrees to the longitudinal direction. It is thereby possible to form a spiral-shaped rolling which enables making of a cylindrical actuator which extends by a very long length in the longitudinal direction.
  • the actuator may be produced as one "endless" cylindrical actuator from which pieces of a specific length are separated. When making the cylindrical actuator, care should be taken that a cutting area remains in which only one side of the first layer is covered with electrically conductive material.
  • indication lines for visually indicating positions of cutting areas on an outer surface of the rolled up actuator.
  • the indication lines could be drawn up by ink or formed as a groove or elevation on the surface of the elastomeric layer
  • the electrically isolating layer could be constituted by a second layer of an elastomeric material, and in a preferred embodiment, the actuator is made from two layers of an elastomeric material, each provided with an electrode, e.g. vaporised onto one surface of the elastomeric layer. Subsequently, the layers are joined and the laminated structure is rolled to form a cylindrical actuator.
  • the top electrode forms part of, or is adhesively joined to one of the elastomeric layers and the back electrode forms part of, or is adhesively joined to the other elastomeric layer, and the layers, i.e. e.g.
  • the invention applies equally by providing cutting areas in which an electrode is provided on at most one surface of each layer of elastomeric material in the stacked structure.
  • the elastomeric layer(s) may comprise opposing curved edge portions forming the longest length of the layer, where the layer is rolled essentially transversely, e.g. perpendicularly, to the curved edge portion.
  • the top and back electrodes are electrically conductive layers, e.g. made of metal.
  • the elastomeric material may have a plurality of corrugations or have a wavy outer surface onto which the top or the back electrode is vaporised.
  • the corrugations or waves could extend mutually parallel in the first direction and thus support deformation in the second direction being perpendicular to the first direction.
  • the corrugated or wavy shape could be formed during manufacturing of the elastomeric body, e.g. in a moulding process.
  • a very thin electrode may be formed onto the corrugations of the body.
  • the relatively low elasticity of the electrode compared to the elasticity of the elastomeric material will effectively prevent deformation in the direction of the corrugations and thus concentrate the deformation on one specific direction being perpendicular to the corrugations.
  • the rolled structure exposes a cavity which is limited in a radial direction by the rolled structure and which is limited in an axial direction by two closure parts fastened at axially opposite ends of the tubular portion.
  • the closure parts may have the shape of axle journals, e.g. comprising fastening means for attaching the actuator to an application, e.g. a robotic handgrip.
  • the core of an elastomeric material could be made by filling the cavity with an elastomeric material, e.g. in a liquid state. Subsequently, the liquid core is hardened, e.g. while the rolled structure is stretched axially.
  • the invention provides a method of making an actuator comprising the steps of:
  • one of the surfaces is covered with a conductive material in the cutting area while the opposite surface of the cutting area is uncovered by the electrically conductive material.
  • the actuator may be rolled to form a cylindrical actuator, and the cylinder may be made by applying the first conductive layer to the first elastomeric layer and the second conductive layer to a second elastomeric layer, the layers being laminated to form a structure of alternating elastomeric layers and conductive layers. Subsequently the laminated structure is rolled.
  • the conductive layers could be connected to an electrical source via the conductive edge portions.
  • the invention provides a method of making an actuator comprising the steps of:
  • the last step of cutting the first layer into separate pieces may preferably take place after covering either the top electrode fields or the back electrode fields with an electrically isolating material, and preferably after rolling the layered structure of elastomeric material, electrodes and isolating material to form a cylindrical actuator.
  • Fig. 1 is a perspective view of a portion of a composite according to an embodiment of the invention
  • Figs. 2a-2f are cross sectional views of a portion of composites according to embodiments of the invention.
  • Fig. 2g is an enlarged section of Fig. 2a/2b/2c/2d/2e/2f,
  • Figs. 3a and 3b show an electroactive composite being exposed to zero electrical potential difference and being exposed to a high electrical potential difference
  • Figs. 4a-4c illustrate the effect of exposing the electroactive composite of Fig. 3a to a high electrical potential difference as shown in Fig. 3b,
  • Figs. 5a and 5b illustrate an example of lamination of composites according to an embodiment of the invention, thereby forming an electroactive multilayer composite
  • Figs. 5c and 5d illustrate an electroactive multilayer composite being exposed to zero electrical potential difference and being exposed to a high electrical potential difference
  • Figs. 6a and 6b illustrate a prior art multilayer composite before and after cutting
  • Figs. 6c and 6d illustrate the multilayer composite with cutting areas before and after cutting
  • Fig. 7 illustrate a two-layer composite with conductive materials across the cutting areas
  • Fig. 8 illustrates a perspective view of two layers which can be joined to form a sheet according to the invention
  • Fig. 9 illustrates the sheet in Fig. 1 being rolled up
  • Fig. 10 illustrates a top view of an elastomeric layer with a row of electrodes
  • Fig. 11 illustrates an alternative and preferred layout of the electrodes on the elastomeric layer
  • Fig. 12 illustrates the sheet in Fig. 4 when it is rolled to form a tubular body
  • Fig. 13 illustrates a sheet with opposing curved edge portions
  • Fig. 14 illustrates a side-view of a laminated structure.
  • Fig. 1 is a perspective view of a portion of a composite 1. The proportions of the composite are distorted in order to illustrate different elements of the composite 1.
  • the composite 1 comprises a film 2 made of a dielectric material having a surface 3 provided with a pattern of raised and depressed surface portions, thereby forming a designed corrugated profile of the surface 3.
  • An electrically conductive layer 4 has been applied to the surface 3, the electrically conductive material being deposited so that the electrically conductive layer is formed according to the pattern of raised and depressed surface portions.
  • the film 2 resembles in some aspects household wrapping film. It has a similar thickness and is comparably pliable and soft. However, it is more elastic than such a film, and has a marked mechanical anisotropy as will be explained in the following.
  • the dielectric material may be an elastomere or another material having similar characteristics.
  • the electrically conductive layer 4 may even out as the film 2 expands, and recover its original shape as the film 2 contracts along the direction defined by arrows 5 without causing damage to the electrically conductive layer 4, this direction thereby defining a direction of compliance. Accordingly, the composite 1 is adapted to form part of a compliant structure capable of withstanding large strains.
  • the corrugated surface profile is directly impressed or moulded into the dielectric film 2 before the electrically conductive layer is deposited.
  • the corrugation allows the manufacturing of a compliant composite using electrode materials of high elastic modulii, e.g. metal electrode. This can be obtained without having to apply pre-stretch or pre- strain to the dielectric film 2 while applying the electrically conductive layer 4, and the corrugated profile of the finished composite 1 does not depend on strain in the dielectric film 2, nor on the elasticity or other characteristics of the electrically conductive layer 4. Accordingly, the corrugation profile is replicated over substantially the entire surface 3 of the dielectric film 2 in a consistent manner, and it is possible to control this replication.
  • the electrically conductive layer 4 may be applied to the surface 3 of the dielectric film 2 using standard commercial physical vapour deposition (PVD) techniques.
  • PVD physical vapour deposition
  • the composite 1 shown in Fig. 1 is designed to have an compliance in the range of the compliance of the dielectric film 2 in the direction defined by arrows 5, and a stiffness in the range of the stiffness of the electrically conductive layer 4 in a direction defined by arrows 6.
  • the composite 1 may be produced in very long lengths, so called “endless" composites.
  • d denotes an average or representative corrugation depth, i.e. an average or representative distance between a raised portion and a neighbouring depressed portion of the pattern.
  • H denotes an average thickness of the dielectric film 2
  • h denotes an average thickness of the electrically conductive layer 4.
  • the average thickness H of the dielectric film 2 is in the range of 10 ⁇ m - 100 //m.
  • Figs. 2a-2c show composites 1 having different corrugation depth d, whereas the corrugation period P is substantially identical for the three composites shown. Comparing the composites 1 of Figs.
  • the corrugation depth d is substantially identical, whereas the corrugation period P of the composite 1 in Fig. 2e is larger than the corrugation period P of the composite 1 shown in Fig. 2d.
  • the composite 1 of Fig. 2f has a smaller corrugation depth d and a larger corrugation period P.
  • the properties of the dielectric films 2 with anisotropic corrugated compliant metallic electrodes in the form of electrically conductive layers 4 as described in accordance with the present invention are optimised by design according to design rules developed by the inventors. These design rules take into consideration the dielectric and mechanical properties of the dielectric material and of the material of the electrically conductive layer.
  • the relative permittivity and breakdown field of the dielectric material on the one hand and electrical potential difference between electrodes on the other hand are the design parameters that determine the range of the average thickness, H of the dielectric film 2.
  • the characteristic properties of the dielectric material are typically supplied by dielectric material manufacturers like Wacker-Chemie and Dow Corning.
  • Corrugation depth, d is optimised with respect to the dielectric film thickness, H, in order to obtain a relatively uniform electric field distribution across the dielectric film situated between the electrodes.
  • Such optimisation step is done using finite element simulations.
  • a high d/H ratio corresponds to a non uniform electric field distribution and a low d/H ratio corresponds to a relatively uniform electric field distribution.
  • Anisotropy and compliance properties are the combined result of the shape and topology given to the surface of the dielectric film, e.g. an elastomer film, by a moulding process on one hand and the electrically conductive layer that takes up the corrugation shape on the other hand.
  • Electrode layer thickness, h, and corrugation period, P are optimised with respect to the corrugation depth, d, in order to obtain a dielectric film with metallic electrodes that is compliant in one 'in the plane' direction and almost not compliant in the transverse 'in the plane' direction.
  • a film that is very compliant in one direction is a film that can be stretched or elongated very much in this direction by applying a relatively low level of forces in this direction without the risk of damaging the electrodes, and a film that will have very limited elongation in the transverse direction when a force is applied in this transverse direction.
  • the d/P and h/d ratios have to be optimized. High d/P ratios result in very compliant electrodes and low d/P ratios result in less compliant electrodes. High h/d ratios result in less compliant electrodes and low h/d ratios result in very compliant electrodes.
  • the degree of anisotropy of the dielectric film with corrugated electrodes is determined by the compliance ratio between the direction in which the composite is compliant and the transverse direction in which the composite is almost not compliant. High compliance ratios result in very anisotropic structures and low ratios result in isotropic-like structures.
  • actuators manufactured in accordance with the present invention i.e. made from a dielectric material with electrodes deposited thereon, has a much lower weight, i.e. at least a factor five smaller, than conventional actuators, such as magnetic actuators, capable of providing a comparable actuation force. This is very important for applications where actuator volume and weight are of relevance.
  • the ratio d/H should be in the range of 1/30 - /4.
  • the thickness of the dielectric film 2 will be approximately 20 ⁇ m.
  • the ratio between the corrugation depth d and the period P of the corrugations, d/P, and the ratio between the thickness h of the electrically conductive layer and the corrugation depth d, h/d are important ratios directly affecting the compliance of the electrode.
  • the ratio d/P is in the range of 1/50 - 2
  • the ratio h/d is in the range of 1/1000 - 1/50.
  • Another issue to take into consideration when defining the average thickness H of the dielectric film 2 is the so-called breakdown electric field related to dielectric materials.
  • an electrically conductive layer 4 is deposited on each surface of the dielectric film 2 thereby forming an electroactive composite, there is a maximum value for the voltage, V between these electrically conductive layers, for a given material thickness, H, i.e. a distance corresponding to the thickness, H, of the dielectric film 2, in order not to exceed the breakdown electric field, V/H, of the material.
  • the dielectric film 2 presents large variations in thickness across a surface area 3, then, for a given voltage between the electrically conductive layers, electric field and thickness variations will be of the same order of magnitude.
  • Figs. 3a and 3b illustrate an electroactive composite 1 comprising two electrically conductive layers 4 separated by a dielectric film 2 being exposed to zero electrical potential difference (Fig. 3a) and being exposed to a high electrical potential difference (Fig. 3b). As illustrated in Fig. 3b the dielectric film 2 is expanded, while the electrically conductive layers 4 are evened out, when exposed to an electrical potential difference. This is shown in detail in Figs. 4a-4c which illustrates portions of a section of the electroactive composite 1 at different steps in time, with hatchings omitted for the sake of clarity. A line of symmetry 10 is indicated at the bottom of each figure, illustrating that the composite 1 is an electroactive composite having an electrically conductive layer 4 deposited on each surface. Fig.
  • FIG. 4a illustrate the electroactive composite 1 being exposed to zero electrical potential difference, the corrugation depth being the designed depth d and the corrugation period being the designed period P.
  • Fig. 4b it is illustrated that the dielectric film 2 is expanded in the compliance direction resulting in a reduced thickness H' of the film. Furthermore, the electrically conductive layer 4 is evened out resulting in a smaller corrugation depth d' and a larger corrugation period P'.
  • Fig. 4c illustrate the electroactive composite 1 at a later time step, the thickness H" of the film 2 being even more reduced, the corrugation depth d" being even smaller and the corrugation period P" being larger.
  • capacitors produced in accordance with the present invention exhibit a 'self-healing' mechanism.
  • a self-healing mechanism is characteristic of capacitors with very thin electrodes. It occurs when the dielectric material of the capacitor presents defects such as inclusions, pinholes, etc. For such a capacitor with a given thickness, when the applied potential difference between electrodes approaches the so-called breakdown voltage defined above, the average electric field approaches the critical breakdown field. However, in regions with defects, it will indeed exceed this critical breakdown field, and a cascading effect due to accelerated and colliding charges across dielectric film thickness at the positions of the defects occurs, thereby inducing a high in-rush transient current across the dielectric material.
  • Self-healing does not take place if the capacitor is made with thick electrodes, because the level of local over-heating is not sufficient to deplete the thick electrode material at the defects. In that case, when the critical breakdown is reached, consequent and instant damage of the capacitor occurs.
  • the inventors of the present invention have made metallic electrodes with thickness up to 0.2 ⁇ m and always observed self-healing, even when operating the capacitor above breakdown. This does not cause any substantial damage to the capacitor, and the capacitor therefore continues to operate.
  • an electroactive multilayer composite 15, 16 comprises at least two composites 1 , each composite 1 comprising a dielectric film 2 having a front surface 20 and a rear surface 21 , the rear surface 21 being opposite to the front surface 20.
  • the front surface 20 comprises a surface pattern 3 of raised and depressed portions and a first electrically conductive layer (not shown) covering at least a portion of the surface portion 3.
  • Fig. 5a only show a portion of a multilayer composite 15 and 16, which portions having proportions out of order for illustration purposes.
  • Figs. 5a and 5b show an electroactive multilayer composite 15 having the first composite 1 arranged with its front surface 20 facing the rear surface 21 of the adjacent composite 1 , in the following referred to in general as a Front-to-Back multilayer composite 15.
  • the electrically conductive layer of the first composite 1 is in direct contact with the rear surface of the second composite 1.
  • the composites 1 are laminated either by the use of an elastomer of the same type as used for producing the dielectric film 2 or alternatively, the two composites 1 are stacked without use of an adhesive.
  • the multilayer composite is made of stacked composites without the use of an adhesive. In these cases, the wave troughs are simply filled with air.
  • the electrically conductive layer of each of the composites may even out as the film expands, and recover its original shape as the film contracts along the direction defined by arrows 5 (see Fig. 5b) without causing damage to the electrically conductive layers, this direction thereby defining a direction of compliance.
  • the multilayer composite 15 shown in Fig. 5b is designed to be very compliant in the direction defined by arrows 5 and designed to be very stiff in the transverse direction defined by arrows 6.
  • Figs. 5c and 5d illustrate the electroactive multilayer composite 15 being exposed to zero electrical potential difference and being exposed to a high electrical potential difference.
  • the dielectric film is expanded, while the electrically conductive layers are evened out, when exposed to an electrical potential difference.
  • the depth of the wave troughs (the corrugation depth d) is reduced when the multilayer composite is exposed to an electrical potential difference.
  • the composites can be bonded by applying a high electrical potential difference to the stacked composites, whereby the film of one composite and the electrically conductive layer of an adjacent composite adhere to each other without the use of an additional adhesive.
  • they may be brought into intimate contact by electrostatic forces.
  • they may adhere to each other by pressing them together, e.g. by the use of rollers, due to the characteristics of the dielectric film which may be slightly tacky when made of an elastomer.
  • Fig. 6a-6b shows the problem with prior art electroactive multilayer composite, where three electroactive composits 30 are stacked on top of each other.
  • Fig. 6a shows the end portion, where there is a section 31 free of electrode 32. This insures a length (as illustrated by arrow 33) of elastomeric surface between two adjacent electrodes 32a and 32b sufficient to prevent short circuiting of the electrodes across the end-edge of the elastomeric layer.
  • a length as illustrated by arrow 33
  • Fig. 6c shows a first aspect of the invention, where almost electrode-free cutting areas is 37 is introduced.
  • a conductive material may connect the electrodes across the cutting areas.
  • the electrode fields 42a and 42b on the elastomere 40 is connected by the conductive material 44 across the otherwise electrode- free cutting areas 46.
  • Similar the electrode fields 43a and 43b on the elastomere 41 are connected by the conductive material 45 across the otherwise electrode-free cutting area 47.
  • the two conductive materials 44 and 45 are seen to be off set in the sense that no conductive material 44 in the cutting area 46 is aligned with conductive material 45 in the cutting area 47.
  • Fig. 8 shows an actuator 101 comprising a first layer 102 of an elastomeric material and a second layer 103 of an elastomeric material.
  • a top electrode forming a row of fields 104 is formed on the first layer, and a back electrode 105 is formed on the second layer.
  • the back electrode comprises an edge portion 106 which covers a peripheral rim portion 107 and therefore facilitates connection of the electrode to a power source. Fingers 108 extend from the edge portion 106 and form areas 109 with no conductive material.
  • the two layers are joined to form a laminated structure with the top electrode on one side of the first elastomeric layer and with the back electrode on the opposite side of the first layer, wherein the back electrode is covered by an electrically isolating layer constituted by the second layer of an elastomeric material.
  • the structure comprises actuator areas where both sides of the first layer are covered by an electrode and cutting areas where only one side of the first layer is covered by electrically conductive material.
  • the electrodes are applied to the elastomeric layers by use of a vapour deposition technique and the layers are glued together by use of regular glue.
  • the sheet is rolled into a cylindrical actuator 110 comprising sections 111 , 112, 113 between which the actuator can be separated into smaller actuators.
  • Fig. 10 shows one way of arranging electrode fields 114 on the elastomeric layer 115.
  • the sheet should preferably be rolled in a direction indicated by the arrow 117. This direction is essentially perpendicular to the direction of the row of electrodes, indicated by the arrow 118.
  • Fig. 11 shows an alternative and preferred way of arranging the electrodes 119.
  • the layers, and thus the sheet 120 extend mainly in a longitudinal direction indicated by the arrow 121.
  • Each electrode comprises an edge portion 122 facing towards an adjacent electrode, which edge portion extends in an edge-portion-direction, indicated by the arrow 123.
  • the edge-portion-direction forms an angle, ⁇ , being different from 90 degrees to the longitudinal direction.
  • Fig. 12 shows the sheet from Fig. 11 when the sheet is rolled around a centre axis 123 to form the cylindrical body 124.
  • the sheet is rolled with an angle, ⁇ corresponding to (90- ⁇ ) degrees between a longest edge 125 of the elastomeric layer 126 and the centre axis 123. Accordingly, the angle between the edges 127 of the electrode fields 128 and the centre axis of the rolled body becomes essentially equal to 90 degrees.
  • the opposite back surface of the elastomeric layer 126 is covered with a similar electrode field.
  • the cylindrical actuator 124 comprises actuation areas 129 and cutting areas 130 in which the cylindrical actuator can be divided into separate actuators without causing short circuiting of the top and back electrodes.
  • Fig. 13 illustrates an embodiment of the invention wherein the laminated structure 131 comprises opposing curved edge portions 132, 133 and electrodes 134 which are electrically connected by a connector 135. Due to the opposing curved edge portions, the structure can be rolled up to form a tubular body without gradually increasing the radial size of the body with the number of turns by which the structure is rolled up.
  • Fig. 14 illustrates a side view of a structure made from two parts 136, 137, wherein each part comprises a layer of an elastomeric material 138, 139 with one of the top electrode 140 or the back electrode 141 located on a surface of the elastomeric material.
  • the top or back electrode could e.g. be vaporised onto the surface.
  • the elastomeric material may e.g. have a thickness in the range of 20-40 ⁇ m and the top and back electrodes may have a thickness in the range of 700-900 angstrom.
  • the two parts are joined, e.g. adhesively, and subsequently the structure is rolled to form a tubular body.

Abstract

L'invention fournit un organe d'actionnement constitué à partir d'une couche d'élastomère (126) dotée d'une zone d'actionnement (129) dans laquelle une surface supérieure et une surface arrière opposée sont toutes deux recouvertes d'un matériau électriquement conducteur (128). Afin de permettre la découpe de l'organe d'actionnement en plus petits organes d'actionnement, l'élastomère comprend une zone de découpe (130) dans laquelle au moins l'une des surfaces supérieure et arrière n'est pas recouverte d'un matériau électriquement conducteur. Selon un mode de réalisation, l'élastomère est enroulé pour former un corps tubulaire (124). L'invention fournit en outre un procédé de réalisation d'une pluralité d'organes d'actionnement en découpant un organe d'actionnement en plus petites pièces.
EP06805548A 2006-11-03 2006-11-03 Transducteur capacitif doté de zones de découpe Withdrawn EP2092580A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/DK2006/000608 WO2008052541A1 (fr) 2006-11-03 2006-11-03 Transducteur capacitif doté de zones de découpe

Publications (1)

Publication Number Publication Date
EP2092580A1 true EP2092580A1 (fr) 2009-08-26

Family

ID=38052792

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06805548A Withdrawn EP2092580A1 (fr) 2006-11-03 2006-11-03 Transducteur capacitif doté de zones de découpe

Country Status (2)

Country Link
EP (1) EP2092580A1 (fr)
WO (1) WO2008052541A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2922237A1 (fr) * 2012-11-14 2014-05-22 Leap Technology Aps Vetement ayant de transducteur

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5944794B2 (ja) * 1975-03-17 1984-11-01 呉羽化学工業株式会社 高分子フイルムの成極方法
US4056742A (en) * 1976-04-30 1977-11-01 Tibbetts Industries, Inc. Transducer having piezoelectric film arranged with alternating curvatures
FR2519293A1 (fr) * 1981-12-31 1983-07-08 Thomson Csf Procede de fabrication d'un bloc en materiau macromoleculaire piezoelectrique et bloc obtenu par ledit procede
US4632856A (en) * 1985-02-06 1986-12-30 Marcus Michael A Multilayer thin film electrical devices free of adhesive
GB8507596D0 (en) * 1985-03-23 1985-05-01 Fulmer Res Inst Ltd Piezoelectric transducer
DE69941195D1 (de) * 1999-05-31 2009-09-10 Nanomotion Ltd Beschleunigungs- und Bremsmethode mit einem piezoelektrischen Motor
US7233097B2 (en) * 2001-05-22 2007-06-19 Sri International Rolled electroactive polymers
JP2003009555A (ja) * 2001-06-25 2003-01-10 Canon Inc 積層電気−機械エネルギー変換素子および振動波駆動装置
JP4220901B2 (ja) * 2001-10-30 2009-02-04 １．．．リミテッド 圧電デバイス
US7038357B2 (en) * 2003-08-21 2006-05-02 Engineering Services Inc. Stretched rolled electroactive polymer transducers and method of producing same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
BENSLIMANE M ET AL: "Mechanical properties of dielectric elastomer actuators with smart metallic compliant electrodes", PROCEEDINGS OF SPIE, SPIE, USA, vol. 4695, 1 January 2002 (2002-01-01), pages 150 - 157, XP002445816, ISSN: 0277-786X, DOI: DOI:10.1117/12.475160 *

Also Published As

Publication number Publication date
WO2008052541A1 (fr) 2008-05-08

Similar Documents

Publication Publication Date Title
US7808163B2 (en) Multilayer composite and a method of making such
US8421316B2 (en) Transducer comprising a composite material and method of making such a composite material
EP2909868B1 (fr) Procédé permettant de métalliser un film diélectrique
EP1919071B1 (fr) Composite diélectrique et procédé de fabriation d'un composite diélectrique
US7843111B2 (en) Dielectric composite and a method of manufacturing a dielectric composite
US8181338B2 (en) Method of making a multilayer composite
EP1919072B1 (fr) Composite multicouche et procédé de réalisation d'un tel composite
US7880371B2 (en) Dielectric composite and a method of manufacturing a dielectric composite
EP1919073B1 (fr) Transducteur capacitif à action directe
US7732999B2 (en) Direct acting capacitive transducer
US7400080B2 (en) Elastomer actuator and a method of making an actuator
US7719164B2 (en) Patterned dielectric elastomer actuator and method of fabricating the same
JP6073697B2 (ja) アクチュエータ素子及びアクチュエータ素子の製造方法
WO2008052541A1 (fr) Transducteur capacitif doté de zones de découpe
CN112313417A (zh) 具有挤压片材的挤压装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20090528

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

17Q First examination report despatched

Effective date: 20091008

DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20140603

REG Reference to a national code

Ref country code: DE

Ref legal event code: R079

Free format text: PREVIOUS MAIN CLASS: H01L0041260000

Ipc: H01L0041047000

REG Reference to a national code

Ref country code: DE

Ref legal event code: R079

Free format text: PREVIOUS MAIN CLASS: H01L0041260000

Ipc: H01L0041047000

Effective date: 20141105