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
  • H10N30/80—Constructional details
  • H10N30/88—Mounts; Supports; Enclosures; Casings
  • H10N30/883—Further insulation means against electrical, physical or chemical damage, e.g. protective coatings
• • 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

Definitions

• the present invention relates to a stretchable protection cover to protect mainly dynamic bodies, such as transducers, from being affected by particles, molecules, fluids etc, in the environment where the dynamic bodies operate.
• the protection cover is formed of composites comprising a film of an elastic material having a surface with raised and depressed surface portions, and a barrier layer positioned onto this surface in a manner where the barrier layer takes form of the film surface.
• such composites further are used to form ring-shaped structures utilizable as O-rings.
• transducers, or actuators are described of the DEAP kind, where a capacitive element is formed by having a deformable but incompressible dielectric material between two opposing electrodes.
• a capacitive element is formed by having a deformable but incompressible dielectric material between two opposing electrodes.
• the present invention relates to protection cover materials especially adapted to protect a dynamic body, and the manner in which they may be positioned and wrapped to protect it. They may be suitable for transducers of the kind disclosed in WO 2008/052559, but the invention is in no manner limited thereto, it could be used to protect any dynamic body operating by changing shape in general.
• DEAP transducers or actuators based on dielectric materials that may be an elastomer or another material having similar characteristics
• the characteristics of these are being affected when small particles, moisture, vapours, fluids, molecules etc., diffuse into the materials, changing e.g. the dielectric constant and the break down level.
• these will in general be referred to a 'particles', this thus taking the meaning of any substances in fluid or liquid for, molecules, fluids, particles, gases, vapours etc. Therefore over time the operation characteristics of the transducers / actuators would change and become unpredictable, and it therefore would have to be changed.
• WO2011151885 disclose a water-repellent film comprising a first layer which has multiple fine protrusions formed on the surface thereof, however the film is to cover optical elements such as lenses having no dynamics and is to form a protection against larger molecules such as water.
• the present invention solves this by introducing a simple and cheap protection cover preventing such particles event as gasses from reaching the dynamic body - at least for a time - and thus prolonging its lifetime.
• first barrier layer being deposited onto at least the first (3) surface, where the composite first surface is provided with a pattern of raised and depressed surface portions and where the barrier layer is formed according to the pattern. Since the composites comprise a barrier material often having a significantly low elasticity that would tend to crack when stretched, therefore the film is introduced such that the barrier layer may even have a modulus of elasticity being higher than the modulus of elasticity of the film.
• the barrier layer takes shape from the surface pattern of the film, and this shape ensures the barrier layer may 'follow' the stretching of the film without cracking.
• the barrier layer may be of any material suitable to form barrier against the particles etc. present in the environment where it is to operate, and may comprise plastics, clays, glass, ceramics, metal material, alloy of metals and / or just mixture of metals, and may even comprise a mixture of such materials.
• the protection cover of the present invention is especially suited to form a barrier cover of dynamic bodies, being bodies able to change their size and / shape in at least one direction, where at least one composite is wrapped at least one time around this dynamic body forming the barrier protection.
• end portions of the composites, or more especially the elastic elements may be exposed to the environment surrounding them, thus forming Open doors' for particles to enter into the inside of the films, this being highly undesirable. Therefore at least one end portion of the composites extends beyond the end of the dynamic body and at least a section of this end portion are rolled in the direction towards the dynamic body.
• the protection cover with advantage may comprise a plurality of individual composites and where some may be of a first group having at least a section of their end portion rolled with a first angular direction in the direction towards the dynamic body. Alternatively or additionally other composites may form a second group having at least a section of their end portion rolled with a second angular direction in the direction towards the dynamic body. In this manner the Open door' has been closed, and there are no longer any ends of the elastic materials exposed directly to the environment surrounding them.
• first and / or second sub-groups are formed by rolling first and / or second groups with a first angular direction or a second angular direction in the direction towards the dynamic body in any number and permutation thereof.
• the end portion of the composites reaching free of the dynamic body is flattened, and this flattened structure of composite(s) is then rolled in the direction towards the dynamic body.
• the surface pattern is corrugated where the raised and depressed surface portions forming waves with troughs and crests extending in essentially one common direction, each wave defining a height being a shortest distance between a crest and neighbouring troughs, such that it has a compliance direction which is at least 50 times larger than the compliance in a direction being at least substantially perpendicular to the compliance direction.
• the protection cover may comprise a plurality of composites where at least one composite consists of materials of the barrier layer being different from at least one other of said composites, these composites are then adapted to form barriers against different particles.
• the present invention also relates to transducers covered by the protection cover as given above, where the transducer is the dynamic body and is formed of similar composites as the protection cover, comprising:
• the electrically conductive layer being deposited onto the surface pattern, the electrically conductive layer having a corrugated shape which is formed by the surface pattern of the film.
• the materials constituting the composite(s) of the transducer are the same as the materials constituting the composite(s) of the protection cover.
• the present protection cover is not used as such to cover a dynamic body, but is formed into an O-ring where the composite(s) are rolled into any number and permutation of first groups, second groups, first super-groups and / or second super-groups until they form a ring- shaped like structure.
• Fig. 1 Composite with a surface having a pattern of raised
• Fig. 3 A pattern of raised and depressed surface portions forming a second embodiment of the stretchable protection cover according to the present invention
• Figs. 4A-C Examples of actuators forming the dynamic bodies suitable to be covered by the stretchable protection cover according to the present invention.
• Fig. 6 Illustration of the stretchable protection cover wrapped around a dynamic body and flattened at the end.
• Figs. 7A-B llustration of the stretchable protection cover wrapped around a dynamic body, flattened at the end and rolled in the direction towards the dynamic body Figs. 8A-B llustration of the stretchable protection cover wrapped around a dynamic body and rolled in the direction towards the dynamic body
• Figs. 9 llustration of the stretchable protection cover having groups and super-groups of layers of the stretchable protection rolled in the direction towards the dynamic body
• present invention being used to form a O-ring.
• FIG. 1 illustrates a first embodiment of the protection cover of the present invention, where a pattern of raised and depressed surface portions in at least a first surface of a film of a deformable / elastic material, such as a polymer or more specifically an elastomer, in the following in general referred to as a elastic material.
• a deformable / elastic material such as a polymer or more specifically an elastomer
• a material of a substantially stiff material is positioned, e.g. by a deposition technique of any kind, as also discussed in relation to the electrically conductive layer of the WO 2008/052559.
• this substantially stiff material will be referred to as a barrier layer, where the barrier layer may be of any material suitable to form a barrier to such particles (fluids, molecules, gasses etc), such as plastics, clays, metal material, alloy of metals or just mixture of metals optionally including other materials too.
• the barrier layer may also be a mixture of such materials. Since the barrier layer is of a substantially stiff material, then this may easily crack the barrier layer upon stretching, thus reducing its barrier efficiency.
• the protection cover is formed as a composite (1) adapted to form part of a compliant structure capable of withstanding large strains.
• the composite (1) comprises a film (2) made of an elastic material having a surface (3) provided with a pattern of raised (7) and depressed (8) surface portions, thereby forming a designed corrugated profile of the surface (3).
• a barrier layer (4) has been applied to the surface (3), the barrier material being deposited so that the shape of the barrier layer (4) is formed according to the pattern of raised (7) and depressed (8) surface portion. This is due to its thickness being significantly smaller than the heights from the depressed (8) to the raised (7) surface portions.
• the elastic material may be a polymer, elastomer or another material having similar characteristics.
• the barrier layer (4) may substantially 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 barrier layer (4), this direction thereby defining a direction of compliance.
• the composite (1) is adapted to form part of a compliant structure capable of withstanding large strains. Due to the stiffness of the barrier layer (4) this composite (1) is much more compliant in the direction (5) than in the orthogonal direction (6). Together such a laminated composite structure (1) forms a flexible (in the present example mainly flexible in one direction) barrier for the diffusion of particles through the composite (1).
• the elastic element (2) being in it self stretchable, forms the wavy structure of the barrier layer (4), and the barrier layer (4) forms a barrier against the diffusion of particles through the composite (1).
• the resulting barrier is improved due to the increased number of layers, but also because of the parallel barrier layers (4) gives so to speak a 'tunnel' where particles (20) may be trapped for a while, and where they may just as well end up leaving the laminated barrier without reaching the object it covers. That the barrier layers (2) are parallel in this context is to be understood in the sense they are parallel within the general tolerances of the manufacturing techniques seen in the large picture disregarding the
• each individual layer of the individual composites (1) is adapted to form barrier against specific particles, so that a protection cover may be formed that is designed to protect against a wide range of particles.
• Fig. 3 illustrates an alternative surface pattern of raised and depressed surface portions, where the raised (7) portions rather are shaped somewhat like
• Figs. 4A to Fig. 4C illustrate examples of a dynamic body (9) where the composites (1) of the present invention with advantage could be used as barrier covers.
• the dynamic bodies (9) illustrated are EAP (or DEAP) transducers formed in similar manners as the composites (1) of the present invention and are also further described in e.g. WO 2008/052559, where one or more of such composites (1) comprising a corrugated surface carrying electrodes are wrapped to form a transducer able to elongate (or widen, this being a matter of the orientation of the corrugations) when a voltage is applied to the electrodes.
• They may be with (Fig. 4B and 4C) or without (Fig. 4A) a hollow core, and may be of a circular (Fig. 4A and 4B) or non-circular (Fig. 4C) cross sectional shapes.
• transducers may be formed of composites like the ones of the present invention they could be manufactured identically by the same tools, optionally even from the same materials, the present composites (1) simply being layers of transducer-composites not being connected to any power-supply.
• Fig. 5 illustrates a protection cover where a plurality of layers of protection cover are wrapped around a dynamic body (9) (a transducer as illustrated in Figs. 4A- C or any other kind of dynamic body), either a as a plurality of individual composites (1) arranged in a laminated manner, or one composite (1) being wrapped a plurality of times, or a combination thereof.
• the composite(s) (1) is wrapped at least one time around the dynamic body (9) in a manner where it is wrapped around a line (10) parallel to a first direction.
• the composite(s) (1), or some of the composites (1), may be positioned on the dynamic body (9) such that an end portion (13) of the composites (1) extends beyond the end of the dynamic body (9), thus forming a tubular section of wrapped protection cover with a hollow inside.
• the composite(s) (1) is / are only seen covering part of the dynamic body (9) and only extending free (13) from one of its ends, but this is purely for illustration, usually the whole of the dynamic body (9) will be covered and the composite(s) (1) extending free (13) from both of its ends.
• this end portion (13) has been 'collapsed' so that at least the end (14) of the end portion (13) is flat and non-hollow, and at least the end part of this end portion (13) is then rolled in the direction of the first line (10) towards the dynamic body (9) in a first angular direction (11), as illustrated in Fig. 7A.
• the illustration in Fig. 7A is highly illustrative and does not reflect the actual sizes or relative sizes of the parts, nor showing the surface pattern of raised (7) or depressed (8) portions.
• Fig. 7A is highly illustrative and does not reflect the actual sizes or relative sizes of the parts, nor showing the surface pattern of raised (7) or depressed (8) portions.
• the composites (1) are just represented by a line, and though in the illustration there may seem to appear 'gaps' between these line, then these 'gaps' are only to be able to distinguish the individual layers, or composites (1), of the protection cover.
• Fig. 7B illustrates the flattened section of the end portion (13) rolled in the direction of the first line (10) towards the dynamic body (9) in a second angular direction (12), the second angular direction (12) being counter-wise to the first angular direction (11).
• Rolling 'in the direction of the first line (10) means rolling around an axis parallel to the first line (10).
• Fig. 8A shows the same system to that of Fig.
• tubular shaped composite(s) (1) is rolled in a first angular direction in the direction of the first line (10) towards the dynamic body (9) such that at least a section of this end portion ( 3) forms a rolled structure encircling the line (10), either outside the remaining part of the protection cover when rolled in the first angular direction (11) as seen in Fig. 8A, or inside the remaining part of the protection cover when rolled in the second angular direction (12) as seen in Fig. 8B.
• This operation is possible due to the flexibility / stretchability of the composites (1).
• 'tubular' is not limited to a rounded shape, e.g. circular or oval, but relates to 'tubes' of any cross sectional shape or profile.
• the end portions (13) exposed to the environment surrounding them extending beyond the end of the dynamic body (9) may be rolled fully or partly and may be rolled tightly or loosely in the manners as described above.
• any number of such first groups (15) and / or second groups (16) may then further be rolled into a first (17) or second (18) kind supergroup, this thus being a group comprising other groups.
• Such super-groups (17) and (18) may comprise any number and permutation of first (15) and second (16) kind of groups and other ssuper-groups (17) and (18).
• any single composite (1) may form part of several groups or super-groups, as also illustrated in Figs. 8A and 8B
• the protection cover is not formed to enclose a dynamic body (9), but instead the end portion (13) is regarded to be the whole extension of the wound or rolled composite(s) (1), these are then rolled in any manner as described above over the whole extension of the composite(s) (1), such they form a ring-shaped (19) like structure.
• the combined rolling may include any permutation and number of first groups (15), second groups (16), first super-groups (17) and / or second super-groups (18).
• Such ring-shaped structures (19), Fig. 10, may then with advantage be used e.g. as highly gas tight O-rings due to their highly flexible / stretchable structure.

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• 2013
  • 2013-02-21 EP EP13707807.7A patent/EP2826077A1/de not_active Withdrawn
  • 2013-02-21 WO PCT/DK2013/000018 patent/WO2013135241A1/en active Application Filing
  • 2013-02-21 CN CN201380012489.8A patent/CN104170108A/zh active Pending

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