Aerosol provision device

Abstract

An aerosol provision device comprising a magnetic field generator (300) comprising a plurality of flexible substrates (301a, 301b, 301c). Each substrate (301a, 301b, 301c) comprises one or more electrically conductive elements. The plurality of substrates (301a, 301b, 301c) are deformed so as to form a substantially tubular element.

Description

[0001] AEROSOL PROVISION DEVICE

[0002] TECHNICAL FIELD

[0003] The present invention relates to an aerosol provision device, an aerosol provision system, a method of manufacturing a magnetic field generator or an aerosol provision device and a method of generating an aerosol.

[0004] BACKGROUND

[0005] Smoking articles such as cigarettes, cigars and the like burn tobacco during use to create tobacco smoke. Attempts have been made to provide alternatives to these articles by creating products that release compounds without combusting. Examples of such products are so-called “heat not burn” products or tobacco heating devices or products, which release compounds by heating, but not burning, material. The material may be, for example, tobacco or other non-tobacco products, which may or may not contain nicotine.

[0006] Aerosol provision systems, which cover the aforementioned devices or products, are known. Common systems use heaters to create an aerosol from a suitable medium which is then inhaled by a user.

[0007] It is known to use an induction heater in the form of a helical inductor coil to heat the medium.

[0008] Conventional aerosol provision devices comprise a cylindrical heating chamber surrounded by a helical inductor coil into which a rod-shaped consumable is inserted. The size of the device is often dictated by the diameter of the helical inductor coil.

[0009] SUMMARY

[0010] According to an aspect there is provided an aerosol provision device comprising: a magnetic field generator comprising a plurality of flexible substrates, wherein each substrate comprises one or more electrically conductive elements, wherein the plurality of substrates are deformed so as to form a substantially tubular element.

[0011] Optionally, the substantially tubular element comprises one or more helical electrically conductive elements.

[0012] According to an aspect there is provided an aerosol provision device comprising: a magnetic field generator comprising a flexible substrate, wherein the substrate comprises one or more electrically conductive elements, wherein the substrate overlaps itself to form a substantially tubular element.

[0013] Optionally, the one or more electrically conductive elements comprise a plurality of electrically conductive tracks arranged to form a plurality of substantially parallel electrical paths.

[0014] Optionally, the or each substrate comprises an electrical insulator.

[0015] Optionally, the or each substrate comprises a polymer or a plastic.

[0016] Optionally, the or each substrate comprises polyimide (“Pl“).

[0017] Optionally, the or each substrate has a thickness of: (i) < 10 pm; (ii) 10-20 pm; (iii) 20-30 pm; (iv) 30-40 pm; (v) 40-50 pm; (vi) 50-60 pm; (vii) 60-70 pm; (viii) 70-80 pm; (ix) 80-90 pm; (x) 90-100 pm; (xi) 100-200 pm; (xii) 200-300 pm; (xiii) 300-400 pm; (xiv) 400-500 pm; (xv) 500-600 pm; (xvi) 600-700 pm; (xvii) 700-800 pm; (xviii) 800-900 pm; (xix) 900-1000 pm; (xx) 1-2 mm; (xxi) 2-3 mm; (xxii) 3-4 mm; (xxiii) 4-5 mm; or (xxiv) > 5 mm.

[0018] Optionally, the one or more electrically conductive elements comprise a metal or metal alloy.

[0019] Optionally, the one or more electrically conductive elements comprise copper, nickel, silver, gold, chromium, palladium, tin, aluminium, platinum, tungsten, brass, bronze or zinc.

[0020] Optionally, the aerosol provision device further comprises a magnetic shielding element.

[0021] Optionally, the magnetic shielding element is arranged to surround at least a portion of the magnetic field generator.

[0022] Optionally, the magnetic shielding element comprises a ferromagnetic material.

[0023] Optionally, the ferromagnetic material comprises one or more from the group consisting of: (i) iron; (ii) nickel; and (iii) cobalt.

[0024] Optionally, the aerosol provision device further comprises a heat insulation member. Optionally, the heat insulation member is surrounded by at least a portion of the magnetic field generator.

[0025] Optionally, the heat insulation member comprises a ceramic or a plastic.

[0026] Optionally, the one or more electrically conductive elements have a thickness of: (i) < 10 pm; (ii) 10-20 pm; (iii) 20-30 pm; (iv) 30-40 pm; (v) 40-50 pm; (vi) 50-60 pm; (vii) 60-70 pm; (viii) 70-80 pm; (ix) 80-90 pm; (x) 90-100 pm; (xi) 100-200 pm; (xii) 200-300 pm; (xiii) 300-400 pm; (xiv) 400-500 pm; (xv) 500-600 pm; (xvi) 600-700 pm; (xvii) 700- 800 pm; (xviii) 800-900 pm; (xix) 900-1000 pm; (xx) 1-2 mm; (xxi) 2-3 mm; (xxii) 3-4 mm; (xxiii) 4-5 mm; or (xxiv) > 5 mm.

[0027] Optionally, the one or more electrically conductive elements have a width of: (i) < 10 pm; (ii) 10-20 pm; (iii) 20-30 pm; (iv) 30-40 pm; (v) 40-50 pm; (vi) 50-60 pm; (vii) 60- 70 pm; (viii) 70-80 pm; (ix) 80-90 pm; (x) 90-100 pm; (xi) 100-200 pm; (xii) 200-300 pm; (xiii) 300-400 pm; (xiv) 400-500 pm; (xv) 500-600 pm; (xvi) 600-700 pm; (xvii) 700-800 pm; (xviii) 800-900 pm; (xix) 900-1000 pm; (xx) 1-2 mm; (xxi) 2-3 mm; (xxii) 3-4 mm; (xxiii) 4-5 mm; or (xxiv) > 5 mm.

[0028] According to an aspect there is provided an aerosol provision system comprising: an aerosol provision device as described above; and an aerosol generating article comprising aerosol generating material.

[0029] According to an aspect there is provided a method of manufacturing a magnetic field generator of an aerosol provision device comprising: providing a plurality of flexible substrates, wherein each substrate comprises one or more electrically conductive elements; and deforming the plurality of substrates so as to form a substantially tubular element.

[0030] According to an aspect there is provided a method of manufacturing a magnetic field generator of an aerosol provision device comprising: providing a flexible substrate, wherein the substrate comprises one or more electrically conductive elements; and deforming the substrate so that the substrate overlaps itself to form a substantially tubular element.

[0031] Optionally, the method further comprises depositing, sputtering, laser direct activating, implanting, etching or printing the one or more electrically conductive elements on or onto the one or more substrates. According to an aspect there is provided a method of generating an aerosol comprising: providing an aerosol provision device comprising a magnetic field generator comprising a plurality of flexible substrates, wherein each substrate comprises one or more electrically conductive elements, wherein the plurality of substrates are deformed so as to form a substantially tubular element; inserting an aerosol generating article comprising aerosol generating material into the aerosol provision device; and activating the aerosol provision device.

[0032] According to an aspect there is provided a method of generating an aerosol comprising: providing an aerosol provision device comprising a magnetic field generator comprising a flexible substrate, wherein the substrate comprises one or more electrically conductive elements, wherein the substrate overlaps itself to form a substantially tubular element; inserting an aerosol generating article comprising aerosol generating material into the aerosol provision device; and activating the aerosol provision device.

[0033] BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Various embodiments will now be described, by way of example only, and with reference to the accompanying drawings in which:

[0035] Fig.lA is a schematic diagram of a known heating assembly of an aerosol provision device comprising a single inductor coil formed from wire wrapped around a tubular support and shows an aerosol generating article partially inserted into the tubular support and Fig. 1 B shows a cross-section of the heating assembly shown in Fig. 1A and shows a tubular susceptor located within the tubular support and an aerosol generating article partially inserted within the tubular susceptor;

[0036] Fig. 2 shows an embodiment wherein one or more copper tracks are shown deposited upon or otherwise provided on a substrate (which may comprise e.g. a polyimide sheet) and wherein the substrate is deformed into a tubular form and wherein positive and negative electrical connections are then attached to the substrate which now has assumed a tubular form;

[0037] Fig. 3 illustrates an embodiment wherein a magnetic field generator is formed from a plurality of flexible substrates (e.g. three substrates), wherein each substrate comprises one or more electrically conductive elements and wherein the plurality of substrates are stacked upon each other and are deformed so as to form a substantially tubular element;

[0038] Fig. 4 shows a cross sectional view of an embodiment wherein a magnetic field generator is formed from a plurality of flexible substrates (e.g. three flexible substrates), wherein each substrate comprises one or more electrically conductive elements and wherein a heat insulation element or layer is provided radially inwards of the flexible substrates and wherein a magnetic shielding element is formed around the substrates;

[0039] Fig. 5 shows an embodiment wherein e.g. copper tracks are formed on to a substrate (such as a polyimide sheet) which is then rolled up or wound so as to form a roll so that the substrate overlaps itself;

[0040] Fig. 6 illustrates a method of manufacturing a magnetic field generator according to an embodiment; and

[0041] Fig. 7 illustrates a method of manufacturing a magnetic field generator according to an embodiment.

[0042] DETAILED DESCRIPTION

[0043] Aspects and features of certain examples and embodiments are discussed or described herein. Some aspects and features of certain examples and embodiments may be implemented conventionally and these are not discussed or described in detail in the interests of brevity. It will thus be appreciated that aspects and features of apparatus and methods discussed herein which are not described in detail may be implemented in accordance with conventional techniques for implementing such aspects and features.

[0044] According to the present disclosure, a “non-combustible” aerosol provision system is one where a constituent aerosol generating material of the aerosol provision system (or component thereof) is not combusted or burned in order to facilitate delivery of at least one substance to a user.

[0045] In some embodiments, the delivery system is a non-combustible aerosol provision system, such as a powered non-combustible aerosol provision system. In some embodiments, the non-combustible aerosol provision system is an electronic cigarette, also known as a vaping device or electronic nicotine delivery system (END), although it is noted that the presence of nicotine in the aerosol generating material is not a requirement. In some embodiments, the non-combustible aerosol provision system is an aerosol generating material heating system, also known as a heat-not-burn system. An example of such a system is a tobacco heating system.

[0046] In some embodiments, the non-combustible aerosol provision system is a hybrid system to generate aerosol using a combination of aerosol generating materials, one or a plurality of which may be heated. Each of the aerosol generating materials may be, for example, in the form of a solid, liquid or gel and may or may not contain nicotine. In some embodiments, the hybrid system comprises a liquid or gel aerosol generating material and a solid aerosol generating material. The solid aerosol generating material may comprise, for example, tobacco or a non-tobacco product.

[0047] Typically, the non-combustible aerosol provision system may comprise a non-combustible aerosol provision device and a consumable for use with the non- combustible aerosol provision device.

[0048] In some embodiments, the disclosure relates to consumables comprising aerosol generating material and configured to be used with non-combustible aerosol provision devices. These consumables are sometimes referred to as articles throughout the disclosure.

[0049] In some embodiments, the non-combustible aerosol provision system, such as a non-combustible aerosol provision device thereof, may comprise a power source and a controller. The power source may, for example, be an electric power source or an exothermic power source. In some embodiments, the exothermic power source comprises a carbon substrate which may be energised so as to distribute power in the form of heat to an aerosol generating material or to a heat transfer material in proximity to the exothermic power source.

[0050] In some embodiments, the non-combustible aerosol provision system may comprise an area for receiving the consumable, an aerosol generator, an aerosol generation area, a housing, a mouthpiece, a filter and / or an aerosol-modifying agent.

[0051] In some embodiments, the consumable for use with the non-combustible aerosol provision device may comprise aerosol generating material, an aerosol generating material storage area, an aerosol generating material transfer component, an aerosol generator, an aerosol generation area, a housing, a wrapper, a filter, a mouthpiece, and / or an aerosol-modifying agent. Aerosol generating material is a material that is capable of generating aerosol, for example when heated, irradiated or energized in any other way. Aerosol generating material may, for example, be in the form of a solid, liquid or semi-solid (such as a gel) which may or may not contain an active substance and / or flavourants.

[0052] The aerosol generating material may comprise a binder and an aerosol former. Optionally, an active and / or filler may also be present. Optionally, a solvent, such as water, is also present and one or more other components of the aerosol generating material may or may not be soluble in the solvent. In some embodiments, the aerosol generating material is substantially free from botanical material. In particular, in some embodiments, the aerosol generating material is substantially tobacco free.

[0053] The aerosol generating material may comprise one or more active substances and / or flavours, one or more aerosol-former materials, and optionally one or more other functional material.

[0054] An aerosol generator is an apparatus configured to cause aerosol to be generated from the aerosol generating material. In some embodiments, the aerosol generator is a heater configured to subject the aerosol generating material to heat energy, so as to release one or more volatiles from the aerosol generating material to form an aerosol. In some embodiments, the aerosol generator is configured to cause an aerosol to be generated from the aerosol generating material without heating. For example, the aerosol generator may be configured to subject the aerosol generating material to one or more of vibration, increased pressure, or electrostatic energy.

[0055] A consumable is an article comprising or consisting of aerosol generating material, part or all of which is intended to be consumed during use by a user. A consumable may comprise one or more other components, such as an aerosol generating material storage area, an aerosol generating material transfer component, an aerosol generation area, a housing, a wrapper, a mouthpiece, a filter and / or an aerosolmodifying agent. A consumable may also comprise an aerosol generator, such as a heater, that emits heat to cause the aerosol generating material to generate aerosol in use. The heater may, for example, comprise combustible material, a material heatable by electrical conduction, or a susceptor.

[0056] Non-combustible aerosol provision systems may comprise a modular assembly including both a reusable aerosol provision device and a replaceable aerosol generating article. In some implementations, the non-combustible aerosol provision device may comprise a power source and a controller (or control circuitry). The power source may, for example, comprise an electric power source, such as a battery or rechargeable battery. In some implementations, the non-combustible aerosol provision device may also comprise an aerosol generating component. However, in other implementations the aerosol generating article may comprise partially, or entirely, the aerosol generating component.

[0057] For completeness, aerosol provision devices comprising an inductive element are known. The aerosol provision device may comprise one or more inductors and a susceptor which is arranged to be heated by the one or more inductors.

[0058] A susceptor is a heating material that is heatable by penetration with a varying magnetic field, such as an alternating magnetic field. The susceptor may be an electrical ly-conductive material, so that penetration thereof with a varying magnetic field causes induction heating of the heating material. The heating material may be magnetic material, so that penetration thereof with a varying magnetic field causes magnetic hysteresis heating of the heating material. The susceptor may be both electrically- conductive and magnetic, so that the susceptor is heatable by both heating mechanisms. The aerosol provision device that is configured to generate the varying magnetic field is referred to as a magnetic field generator, herein.

[0059] Fig. 1A shows a conventional induction heating assembly 100 for an aerosol provision device and Fig. 1B shows a cross section of the induction heating assembly 100 of the aerosol provision device as shown in Fig. 1A. The heating assembly 100 comprises a tubular support upon which a helical inductor coil 112 is formed from wire. The heating assembly 100 has a first or proximal or mouth end 102 and a second or distal end 104. An aerosol generating article 130 is shown inserted into the tubular support. As shown in Fig. 1 B, a tubular susceptor 140 is located within the tubular support and the aerosol generating article 130 is shown partially located within the tubular susceptor 140.

[0060] In use an AC electric current is passed through the helical inductor coil 112 which results in the generation of a varying magnetic field which generates eddy currents within the susceptor 140 thereby rapidly heating the susceptor 140. As a result, an aerosol generating article 130 at least partially inserted within the susceptor 140 is rapidly heated and results in aerosol being generated.

[0061] In use, a user inhales aerosol which has been formed within the aerosol provision device from the mouth end 102 of the aerosol provision device. The mouth end 102 may be an open end. The heating assembly 100 may be considered as comprising an induction heating unit which comprises the inductor coil 112 and the susceptor 140. Figs. 1A and 1 B also show an aerosol generating article 130 partially received within the susceptor 140. The susceptor 140 may be formed from any material suitable for heating by induction. The susceptor 140 may comprise a ferrous material such as iron, nickel or cobalt. The susceptor 140 defines a receptacle to surround the aerosol generating article 130 and heat the aerosol generating article 130 externally.

[0062] The inductor coil 112 is made from LITZ wire which is wound in a helical fashion to provide a helical inductor coil 112. LITZ wire comprises a plurality of individual wires which are individually insulated and which are twisted together to form a single wire. The inductor coil 112 is made from copper LITZ wire which has a circular cross section.

[0063] The inductor coil 112 is configured to generate a varying magnetic field for heating the induction element 114. The inductor coil 112 and the susceptor 140 taken together form an induction heating unit.

[0064] The susceptor 140 is hollow and defines a receptacle within which aerosol generating material is received. For example, the aerosol generating article 130 can be inserted into the susceptor 140. The susceptor 140 is tubular with a circular cross section.

[0065] The susceptor 140 is arranged to surround the aerosol generating article 130 and heat the aerosol generating article 130 externally. The aerosol provision device is configured such that, when the aerosol generating article 130 is received within the susceptor 140, the outer surface of the aerosol generating article 130 abuts the inner surface of the susceptor 140. This ensures that the heating is most efficient. The aerosol generating article 130 comprises aerosol generating material. The aerosol generating material is positioned within the susceptor 140. The aerosol generating article 130 may also comprise other components such as a filter, wrapping materials and / or a cooling structure.

[0066] It will be understood that a LITZ wire is limited to one diameter only i.e. the diameter of a LITZ wire cannot be readily varied across its length. The diameter, number of turns and thickness of the LITZ wire are selected based on the desired target operating temperature to heat an aerosol generating article. These limitations dictate the overall size of the aerosol generating device, as it needs to be sufficiently sized to accommodate the LITZ wire.

[0067] In addition, the diameter of the LITZ wire will also dictate the outer skin temperature of the aerosol generating device. The outer skin temperature can be defined as the temperature of the outer surface of the aerosol provision device e.g. the surface that a user will touch when using the aerosol provision device. In use, once an aerosol generating article has been heated, it is desired to cool the outer skin temperature as quickly as possible, and indeed prevent it from heating up at all. In order to facilitate this when using conventional LITZ wire as the inductor coil, a sufficiently large air gap is required. It will therefore be understood that the presence of an air gap will further increase the size of the aerosol provision device.

[0068] It is known to use an inductive coil to heat up the susceptor wherein the susceptor heats up the tobacco. It is widely used that the conductive wires wind around the susceptor. The known arrangements present challenges to the assembly process. It is also desired to deliver the heat evenly.

[0069] With reference to Fig. 2, according to various embodiments a magnetic field generator 200 is disclosed, the magnetic field generator 200 comprising one or more electrically conductive elements 202, in the present example, comprising one or more electrically conductive tracks 202 are deposited onto or are otherwise formed on a flexible substrate 201. The flexible substrate is an electrically insulative substrate or sheet 201. The one or more electrically conductive tracks 202 may, for example, comprise copper, and may be referred to as copper tracks 202.

[0070] In the present example, as shown in the left hand image in Fig. 2, a plurality of electrically conductive elements 202 are formed on a substantially planar substrate 201. The plurality of electrically conductive elements 202 extend in substantially straight lines. The plurality of electrically conductive elements 202 are substantially parallel to each other.

[0071] The substrate 201 may be formed from a polymer or plastic and may, for example, comprise a polyimide (PI) film. The substrate 201 is flexible so that it may be deformed e.g. to assume a substantially tubular shape.

[0072] The magnetic field generator 200 may comprise one or more connecting holes 203, which may be provided close to the edge of the sheet 201. The electrically conductive elements 202 extend to a respective connecting hole 203. The electrically conductive elements 202 extend from a first edge 204 of the sheet 201 to their respective connecting hole 203.

[0073] The connecting holes 203 are substantially aligned with each other along a line parallel to the first edge. The connecting holes 203 are close to a second edge 205 of the sheet 201. The second edge 205 opposes the first edge 204. The electrically conductive elements 202 are angled with respect to the first edge 204. The electrically conductive elements 202 are angled with respect to the second edge 205. The electrically conductive elements 202 are angled such that when the substrate 201 is rolled as described below, the connecting hole 203 of an electrically conductive element 202 aligns with the next electrically conductive element at the first edge 204 (i.e. an end of an electrically conductive element aligns with a start of another electrically conductive element).

[0074] As the insulator sheet 201 is flexible, it can be rolled into a tube or tubular shape to form a substantially element. The sheet 201 is rolled such that it overlaps itself. The sheet 201 overlaps itself such that the second edge 205 overlaps the first edge 204. According to various embodiments the start and the end of each electrically conductive element may be aligned. According to various embodiments the two ends of a electrically conductive element may then be electrically connected to each other (e.g. by welding, gluing, or soldering) together via the connecting holes 203. As a result some or all of the individual electrically conductive elements 202 may be connected so as to form a single helical circuit. In effect, a magnetic field generator 200 may be formed comprising a helical arrangement of electrically conductive elements / tracks 202 formed by deforming a substrate 201 into a tubular element. Electrical power may be connected to the ends of the tubular element thereby creating an inductive coil unit.

[0075] With reference to Fig. 3, in order to enhance performance of the aerosol provision device it may be desirable to increase the power of the RF electromagnetic waves generated by the magnetic field generator 300. In particular, according to various embodiments the power may be multiplied by wrapping or deforming one or more substrates 301 into a tubular element with a plurality of layers of substrates. In the present example, this is achieved by deforming a plurality of substrates 301a, 301b and 301c. According to embodiments each substrate may be connected to positive and negative terminals in parallel.

[0076] The plurality of substrates 301 a-c each with associated electrically conductive elements (not shown in Fig. 3) may then be rolled or deformed so as to form a single cylindrical tubular element.

[0077] In other examples, a substrate may be deformed to overlap itself multiple times to provide the plurality of layers.

[0078] With reference to Fig. 4, the tubular element formed as in Fig. 2 or 3may then be wrapped externally with a magnetic shielding element 207. Accordingly, an aerosol provision device may be provided further comprising a magnetic shielding element 207. The magnetic shielding element 207 may be arranged to surround at least a portion of the magnetic field generator 200, 300. The magnetic shielding element 207 may comprise a ferromagnetic material. According to embodiments, the ferromagnetic material may comprise iron and / or nickel and / or cobalt. The magnetic shielding element 207 may reduce the formation of a magnetic field outside the magnetic field generator 200, 300.

[0079] The aerosol provision device may further comprise a heat insulation member 208. The heat insulation member 208 may be surrounded by at least a portion of the magnetic field generator 200, 300. The heat insulation member 208 may comprise a ceramic or a plastic. The heat insulation 208 may reduce heating of the magnetic field generator 200, 300 by heat from a susceptor located within the magnetic field generator 200, 300.

[0080] The flexible substrates 201 with electrically conductive elements and optionally a magnetic shielding element 207 and / or heat insulation member 208 may be formed together in a modular arrangement thereby facilitating ease of handling and / or assembly e.g. during the manufacturing process thereby reducing costs and / or complexity associated with assembly.

[0081] As a general comment according to an embodiment copper tracks 202 may be deposited onto a flexible polyimide sheet 201 such that the copper tracks act in an equivalent manner to electrically conductive wires. Embodiments are contemplated wherein the thickness and / or the pitch of the electrically conductive tracks 202 formed on the polyimide sheet 201 may be varied. In particular, by varying the thickness and / or pitch of the electrically conductive tracks 202 allows for different electrical power / heating effect to be delivered in different (heating) zones as desired.

[0082] The heat insulation member 208 may be surrounded by at least a portion of the magnetic field generator and the heat insulation member 208 may comprise a ceramic or a plastic.

[0083] The one or more electrically conductive elements 202 may have a thickness of: (i) < 10 pm; (ii) 10-20 pm; (iii) 20-30 pm; (iv) 30-40 pm; (v) 40-50 pm; (vi) 50-60 pm; (vii) 60-70 pm; (viii) 70-80 pm; (ix) 80-90 pm; (x) 90-100 pm; (xi) 100-200 pm; (xii) 200-300 pm; (xiii) 300-400 pm; (xiv) 400-500 pm; (xv) 500-600 pm; (xvi) 600-700 pm; (xvii) 700- 800 pm; (xviii) 800-900 pm; (xix) 900-1000 pm; (xx) 1-2 mm; (xxi) 2-3 mm; (xxii) 3-4 mm; (xxiii) 4-5 mm; or (xxiv) > 5 mm. The one or more electrically conductive elements 202 may have a width of: (i) < 10 pm; (ii) 10-20 pm; (iii) 20-30 pm; (iv) 30-40 pm; (v) 40- 50 pm; (vi) 50-60 pm; (vii) 60-70 pm; (viii) 70-80 pm; (ix) 80-90 pm; (x) 90-100 pm; (xi) 100-200 pm; (xii) 200-300 pm; (xiii) 300-400 pm; (xiv) 400-500 pm; (xv) 500-600 pm; (xvi) 600-700 pm; (xvii) 700-800 pm; (xviii) 800-900 pm; (xix) 900-1000 pm; (xx) 1-2 mm; (xxi) 2-3 mm; (xxii) 3-4 mm; (xxiii) 4-5 mm; or (xxiv) > 5 mm.

[0084] As discussed above, an advantage of the disclosed arrangement is that it is easy to be modularized. The substrate 201 with electrically conductive elements 202 may be rolled or otherwise deformed into shape and then combined e.g. with a magnet shielding sheet 205 and / or a heat insulative sheet 204 resulting in a modular component which may be supplied separately and which is convenient to handle and assemble in a production line.

[0085] Accordingly, an aerosol provision device may be provided comprising a magnetic field generator 200 300 comprising one or more flexible substrates 201. Each substrate 201 may comprise one or more electrically conductive elements 202 wherein each of the plurality of substrates 201 are deformed so as to form a substantially tubular element. When each substrate 201 is deformed into a tubular element then the electrically conductive tracks 202 on each substrate 201 may be arranged so as to form one or more helical electrically conductive elements or tracks. The plurality of substrates 201 may comprise an electrical insulator such as a polymer or a plastic. In particular, the or each substrate 202 may comprises polyimide (“Pl“). The or each substrate 201 may have a thickness of: (i) < 10 pm; (ii) 10-20 pm; (iii) 20-30 pm; (iv) 30-40 pm; (v) 40-50 pm; (vi) 50-60 pm; (vii) 60-70 pm; (viii) 70-80 pm; (ix) 80-90 pm; (x) 90-100 pm; (xi) 100- 200 pm; (xii) 200-300 pm; (xiii) 300-400 pm; (xiv) 400-500 pm; (xv) 500-600 pm; (xvi) 600-700 pm; (xvii) 700-800 pm; (xviii) 800-900 pm; (xix) 900-1000 pm; (xx) 1-2 mm; (xxi) 2-3 mm; (xxii) 3-4 mm; (xxiii) 4-5 mm; or (xxiv) > 5 mm.

[0086] The one or more electrically conductive elements 202 may more generally comprise a metal or metal alloy. For example, the one or more electrically conductive elements 201 may comprise copper, nickel, silver, gold, chromium, palladium, tin, aluminium, platinum, tungsten, brass, bronze or zinc.

[0087] Fig. 4 shows an embodiment wherein heat insulation material 208 and magnet shielding material 207 may also be integrated into the coil. The subassembly may be produced as a module which simplifies the handling and assembling process.

[0088] A further embodiment is shown and described with reference to Fig. 5 wherein an electrically conductive element 202a (e.g. copper tracks) is deposited or otherwise provided on a substrate 201 such as a polyimide sheet 201. The substrate 201 (e.g. polyimide sheet 201) is then rolled or wound into a roll so that the substrate or sheet 201 overlaps itself. In particular, when viewed in cross section the roll may comprise at least 2, 3, 4, 5, 6, 7, 8, 9 or 10 windings i.e. the substrate or sheet 201 may be arranged to overlap itself at least 2, 3, 4, 5, 6, 7, 8, 9 or 10 times. According to various embodiments, and as illustrated in Fig. 5, the electrically conductive element may have a positive and negative electrical terminal which may be connected to an electrical power source (e.g. battery and power control unit) so that a magnetic field generator (e.g. inductive coil unit) is formed. The magnetic field generator which is formed may comprise a flexible substrate 201 , wherein the substrate 201 comprises one or more electrically conductive elements 202a, wherein the substrate 201 is wound so as to form a roll so that the substrate 201 overlaps itself. The one or more electrically conductive elements 202a may comprise a plurality of electrically conductive tracks which as shown in Fig. 5 are arranged to form a plurality of parallel electrical paths.

[0089] According to various embodiments an aerosol provision system is disclosed comprising an aerosol provision device as described above in combination with an aerosol generating article comprising aerosol generating material.

[0090] Fig. 6 illustrates a method 600 of manufacturing a magnetic field generator of an aerosol provision device according to an embodiment. The method 600 comprises a first step 601 of providing a plurality of flexible substrates, wherein each substrate comprises one or more electrically conductive elements. The method 600 then comprises a second step 602 of deforming the plurality of substrates so as to form a substantially tubular element.

[0091] Fig. 7 illustrates a method 700 of manufacturing a magnetic field generator of an aerosol provision device according to another embodiment. The method 700 comprises a first step 701 of providing a flexible substrate, wherein the substrate comprises one or more electrically conductive elements. The method 700 then comprises a second step 702 of winding the substrate so as to form a roll so that the substrate overlaps itself.

[0092] The method further comprises depositing, sputtering, laser direct activating, implanting, etching or printing the one or more electrically conductive elements on or onto the one or more substrates.

[0093] A method of generating an aerosol is also disclosed comprising providing an aerosol provision device comprising a magnetic field generator comprising a plurality of flexible substrates. Each substrate comprises one or more electrically conductive elements. The plurality of substrates are deformed so as to form a substantially tubular element. The method further comprises inserting an aerosol generating article comprising aerosol generating material into the aerosol provision device. The method may further comprise activating the aerosol provision device.

[0094] A method of generating an aerosol is also disclosed comprising providing an aerosol provision device comprising a magnetic field generator comprising a flexible substrate. The substrate comprises one or more electrically conductive elements, wherein the substrate is wound so as to form a roll so that the substrate overlaps itself. The method may further comprise inserting an aerosol generating article comprising aerosol generating material into the aerosol provision device and activating the aerosol provision device.

[0095] Further embodiments are contemplated wherein the substrate which is deformed or wound to form a magnetic field generator (which functions in an equivalent manner to an inductor coil) may be formed by directing a laser onto the surface of the flexible support to form laser activated regions. The flexible support may be formed from a thermoplastic material such as polyetheretherketone (PEEK) which has been doped with a metallic inorganic compound. The laser creates a laser activated region upon the flexible support which can then be (further) metallised using e.g. an electroless plating process to build up one or more conductive layers of e.g. copper.

[0096] According to various embodiments the laser may be arranged to form a conductor track structure on a non-conductive support. The conductor track structure may be formed of metal nuclei created by breaking up very finely distributed non- conductive metal compounds contained in the flexible support. The non-conductive metal compounds contained in the flexible support material may be broken up or otherwise activated by irradiating portions of the flexible supporting material with electromagnetic radiation.

[0097] The non-conductive metal compounds may comprise thermally stable inorganic oxides which are stable and insoluble in aqueous acid or alkaline metallization baths, and which are selected from the group consisting of higher oxides which contain at least two different kinds of cations and which have a spinel structure or spinel-related structure, and which remain unchanged in non-irradiated areas of the flexible supporting material.

[0098] Classic spinels are mixed metal oxides of magnesium and aluminium, but the magnesium may be wholly or partially replaced by iron, zinc and / or manganese, and the aluminium by iron and / or chromium. Spinel-related mixed oxide structures also may contain nickel and / or cobalt cations.

[0099] According to various embodiments an aerosol provision device may be provided comprising a magnetic field generator formed as described above and a susceptor. The susceptor may be located within a volume defined by the magnetic field generator. The susceptor may be formed from any material suitable for heating by induction. For example, the susceptor may comprise metal. In some examples, the susceptor may comprise non-ferrous metal such as copper, nickel, titanium, aluminium, tin or zinc and / or ferrous material such as iron, nickel or cobalt. Additionally or alternatively, the susceptor may comprise a semiconductor such as silicon carbide, carbon or graphite. The susceptor may have any suitable shape. According to embodiments the susceptor may define a receptacle to surround an aerosol generating article and to heat the aerosol generating article externally. In other embodiments, one or more susceptors may be substantially elongate, arranged to penetrate an aerosol generating article and heat the aerosol generating article internally.

[0100] The magnetic field generator formed from one or more flexible substrates as described above may be configured to generate a varying magnetic field for heating a susceptor and may operate or otherwise function in substantially the same way as the inductor coil 112 as described above with reference to Figs. 1A and 1 B. The varying magnetic field generates eddy currents within a susceptor thereby rapidly heating the susceptor to a maximum operating temperature within a short period of time from supplying an alternating current to the magnetic field generator e.g. within 20, 15, 12, 10, 5, or 2 seconds. The susceptor may comprise a single susceptor. Alternatively, multiple susceptors may be provided.

[0101] Ends of the magnetic field generator formed from one or more flexible substrates as described above may be connected to a controller such as a PCB. The controller may comprise a proportional integral derivative (“PID”) controller.

[0102] According to various embodiments the susceptor may be hollow and may form or define a receptacle within which aerosol generating material may be received. For example, an aerosol generating article may be inserted into the susceptor. The susceptor may be tubular, with a circular cross section. The susceptor may be arranged to surround an aerosol generating article to heat the aerosol generating article externally.

[0103] According to embodiments a magnetic field generator may be formed from a flexible substrate using a process known as laser direct structuring (“LDS”). According to various embodiments a laser may be used to activate the surface of the flexible substrate which may comprise a thermoplastic material such as polyetheretherketone (PEEK) which may have been doped with a metallic inorganic compound. The laser creates one or more laser activated regions upon the flexible substrate which can then (optionally) be (further) metallised using e.g. an electroless plating process to build up one or more conductive layers of e.g. copper.

[0104] According to the embodiment a flexible substrate may be shaped so as to form a uniform helical inductor coil or other magnetic field generator. However, other embodiments are also contemplated wherein the magnetic field generator may have a different configuration. It is also contemplated that various novel electrode structures may be created. For example, the one or more electrically conductive elements provided on one or more flexible substrates may be arranged to have a thickness which is different or which varies along the length of the resulting electrically conductive pathway. It is contemplated, for example, that the thickness of the one or more electrically conductive elements may not be constant. It is known that the magnetic field strength of a coil is given by:

[0105] H = - ‘^ (1) wherein H is the strength of the magnetic field in ampere-turns / metre (At / m), N is the number of turns of the coil, I is the current flowing through the coil in amps (A) and L is the length of the coil in metres (m).

[0106] The resistance R of a wire (electrode) is known to be inversely proportional to the cross sectional area of the wire (electrode): wherein p is the resistivity, L is the length of the wire (electrode) and A is the cross- sectional area of the wire (electrode).

[0107] Accordingly, as the cross-sectional area A of a wire (or electrode or electrically conductive element) increases then it will be understood that the resistance of the wire (or electrode or electrically conductive element) will decrease. As a result, for a given voltage a larger current may be passed through a wire (or electrode or electrically conductive element) having a relatively large cross-sectional area compared to through a wire (or electrode or electrically conductive element) having a relatively low cross- sectional area.

[0108] From Eqn. 1 above it follows that the magnetic field strength increases for a wire (or electrode or electrically conductive element) having a relatively large cross-sectional area.

[0109] Accordingly, providing a coil or electrode structure or electrically conductive element wherein the thickness of the coil or electrode or electrically conductive element is different at different positions along the length of the coil or electrode or electrically conductive element enables the magnetic field strength along the length of the coil or electrode or electrically conductive element to vary. For example, according to an embodiment the coil or electrode or electrically conductive element may comprise a first section having a first cross-sectional area and a second section having a second different cross-sectional area. As a result, the resulting magnetic field strength resulting from an alternating current being passed through the two sections may also differ. As a result, a first current may be induced in a first corresponding portion of a susceptor and a second different current may be induced in a second different portion of the susceptor (or in a separate susceptor). This enables the resulting heating effect to be different in the two different sections of the susceptor.

[0110] According to various embodiments providing a coil or electrode or electrically conductive element having a portion having an increased thickness or cross-sectional area enables a higher magnitude magnetic field to be generated than a coil or electrode or electrically conductive element having a smaller thickness or cross-sectional area. As result, a coil or electrode or electrically conductive element may be provided which results in different heating characteristics at different axial positions along the axial length of the aerosol provision device. For example, an area of increased thickness will heat the area of the susceptor that it is adjacent to a higher degree than an area of reduced thickness.

[0111] According to various embodiments the coil or electrode or electrically conductive element may have a uniform thickness and / or width or a varied thickness and / or width along its length. According to various embodiments the coil or electrode or electrically conductive element may have a rectangular cross-sectional profile having a width in a direction parallel to the surface of the flexible substrate and a depth or thickness in a direction perpendicular to the surface of the flexible substrate. The coil or electrode or electrically conductive element may have a width: (i) < 10 pm; (ii) 10-20 pm; (iii) 20-30 pm; (iv) 30-40 pm; (v) 40-50 pm; (vi) 50-60 pm; (vii) 60-70 pm; (viii) 70-80 pm; (ix) 80-90 pm; (x) 90-100 pm; or (xi) > 100 pm. The coil or electrode or electrically conductive element may have a depth or thickness: (i) < 10 pm; (ii) 10-20 pm; (iii) 20-30 pm; (iv) 30- 40 pm; (v) 40-50 pm; (vi) 50-60 pm; (vii) 60-70 pm; (viii) 70-80 pm; (ix) 80-90 pm; (x) 90- 100 pm; or (xi) > 100 pm.

[0112] According to various embodiments the coil or electrode or electrically conductive element may have a relatively thin thickness (e.g. < 1 pm) if the coil or electrode or electrically conductive element comprises solely laser activated regions of the flexible substrate. The thickness of the coil or electrode or electrically conductive element may be increased by depositing one or more conductive layers upon the laser activated regions. The one or more conductive layers which are deposited upon the laser activated regions may have a thickness > 10 pm.

[0113] According to various embodiments the coil or electrode or electrically conductive element may have a cross-sectional area selected from the group consisting of: (i) < 100 pm2; (ii) 100-200 pm2; (iii) 200-300 pm2; (iv) 300-400 pm2; (v) 400-500 pm2; (vi) 500-600 pm2; (vii) 600-700 pm2; (viii) 700-800 pm2; (ix) 800-900 pm2; (x) 900-1000 pm2; or (xi) > 1000 pm2. According to various embodiments the coil or electrode or electrically conductive element may have a constant number of turns per unit length or the number of turns per unit length may be different at different sections of the coil or electrode or electrically conductive element. For example, a coil or electrode or electrically conductive element provided on a flexible substrate as described above may have a total length L and the coil or electrode or electrically conductive element may be considered as comprising two sections. The coil or electrode or electrically conductive element may comprise two equal sections L1 and L2 i.e. length L1 is the same as the length L2 and the number of turns per unit length in section L1 is the same as the number of turns per unit length in section L2. However, embodiments are also contemplated wherein the number of turns per unit length may be greater in section L1 than the number of turns per unit length in section L2 or vice versa. Embodiments are also contemplated wherein the coil or electrode or electrically conductive element may comprise a plurality of sections and wherein at least some of the sections may have a different or the same number of turns per unit length.

[0114] The variation in the number of turns can increase or decrease the rate at which the susceptor can reach a maximum operating temperature. Such an arrangement may provide asymmetrical heating of an aerosol generating article along the length of the aerosol generating article, if desired.

[0115] In examples, the pitch of a coil or electrode or electrically conductive element as described above may not remain constant. Varying the pitch of the coil or electrode or electrically conductive element can change the heating characteristics of the aerosol provision device at different locations of the coil or electrode or electrically conductive element. For example, an area of reduced pitch will mean there is an increased number of turns per unit length, thereby heating the area of a susceptor that it is adjacent to a higher degree than an area adjacent a section of the coil or electrode or electrically conductive element which has a lower number of turns per unit length.

[0116] As will be appreciated, the number of turns of a coil is inversely proportional to its pitch. Thus, the variation in the pitch of the coil or electrode or electrically conductive element in turn leads to a variation in the number of turns of the coil or electrode or electrically conductive element which can increase or decrease the rate at which a susceptor can reach a maximum operating temperature. Such an arrangement may provide asymmetrical heating of the aerosol generating article along the length of the aerosol generating article, if desired.

[0117] According to various embodiments the coil or electrode or electrically conductive element may have a substantially constant pitch per unit length, and therefore a substantially constant number of turns per unit length. The height of one complete helix turn in coil or electrode or electrically conductive element may be substantially constant along at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% of the axial length of the coil or electrode or electrically conductive element.

[0118] In examples, the coil or electrode or electrically conductive element can have a helical section having a first pitch P1 or P1 turns per unit length i.e. wherein the height of one complete helix turn is P1, a second different helical section having a second pitch P2 or P2 turns per unit length i.e. wherein the height of one complete helix turn is P2, such that P1 P2.

[0119] In examples, the coil or electrode or electrically conductive element can have a substantially constant width and / or a substantially constant length and / or a substantially constant thickness along at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% of the axial length of the respective coil.

[0120] In examples, the coil or electrode or electrically conductive element can have a first helical section having a width W1 and / or a length L1 and / or a thickness T1, a second different helical section having a width W2 and / or a length L2 and / or a thickness T2, such that W1 W2 and / or L1 L2 and / or T1 T2. It will be understood that such configurations are not possible with a conventional inductor coil such as that described with reference to Figs. 1A and 1 B, because the number of turns per unit length is constant, and a LITZ coil is of a constant thickness and diameter.

[0121] The coil or electrode or electrically conductive element (or more generally electrode arrangement) may be formed, deposited or coated in the flexible substrate and / or onto the flexible substrate such that the coil or electrode or electrically conductive element or electrode arrangement has a square, rectangular or polygonal cross- sectional profile. The flexible substrate may comprise a thermoplastic material such as polyetheretherketone (“PEEK”). According to various embodiments the diameter of the coil or electrode or electrically conductive element or electrode arrangement may be in the range < 10 mm, 10-11 mm, 11-12 mm, 12-13 mm, or 14-15 mm.

[0122] Utilising a laser direct structuring process to form a coil or electrode or electrically conductive element or electrode arrangement in and / or on a flexible substrate results in a coil or electrode or electrically conductive element or electrode arrangement being formed which is integrated with or into the flexible substrate. This advantageously reduces the diameter of the flexible substrate required (in the case where the flexible substrate has a tubular structure) compared to conventional arrangements, such as those described with reference to Figs. 1A and 1B. It will be understood that integrating the coil or electrode or electrically conductive element into a shaped flexible substrate enables a more compact arrangement to be provided. The compact flexible substrate of the disclosed arrangement also means that any air gap between the flexible substrate and a housing of an aerosol provision device can be reduced as compared to conventional arrangements, such as those described with reference to Figs. 1A and 1 B. This also results in more efficient cooling. The improved efficiency enables a smaller battery to be utilised in order to power the aerosol provision device in use thereby reducing recharge times. Overall, a more compact, lighter, robust, customisable and more energy efficient heating arrangement may be provided.

[0123] The coil or electrode or electrically conductive element may be formed by depositing, coating or otherwise forming an electrode structure onto an exterior surface of the flexible substrate. However in other examples, the coil or electrode or electrically conductive element or electrode structure can be deposited, coated or otherwise formed on an interior surface of the flexible substrate via a laser direct structuring process.

[0124] According to an embodiment the length L of the coil or electrode or electrically conductive element may be substantially 585 mm, the total number of turns may be 18 and the coil pitch may be substantially 2 mm. However, other embodiments are contemplated wherein the length L of the coil may be shorter or longer than 585 mm. Similarly, the number of turns may be less or greater than 18. It is also contemplated that the coil pitch may be less than 2 mm or greater than 2 mm.

[0125] According to various embodiments the flexible support may be moulded from a material having a high thermal stability, good isotropic component behaviour and which is suitable for metallisation. PEEK has been found to be particularly suitable for the process but other materials may be used including polyphthalamide (PPA) or liquid crystal polymer (LCP). As described above, the flexible support may alternatively be formed from polyimide.

[0126] The flexible support may be formed from a thermoplastic which is doped with a non-conductive metallic inorganic compound. For example, the non-conductive metallic inorganic compound may include copper. However, other embodiments are contemplated where the additive may include nickel, silver, gold, chromium, palladium, tin, aluminium, platinum, tungsten or zinc.

[0127] According to various embodiments the flexible support may be made from a thermoplastic having a composition comprising: (i) 20 to 90 wt% of a thermoplastic resin; (ii) a laser direct structuring additive; and (iii) optionally ceramic filler particles which may not have a laser direct structuring additive function.

[0128] According to various embodiments the laser direct structuring additive may comprise a non-conductive metallic inorganic compound. However, other embodiments are contemplated wherein the laser direct structuring additive may comprise a conductive metal oxide. The conductive metal oxide may have a resistivity of at most 5 x 103Q cm. The conductive metal oxide may comprise at least a metal of Group n of the periodic table and / or a metal of Group n+1 , wherein n is an integer of 3 to 13. Suitable metals of Group n and / or Group n+1 of the periodic table include, for example, Group 4 (titanium, zirconium), Group 5 (vanadium, niobium), Group 6 (chromium, molybdenum), Group 7 (manganese), Group 8 (iron, ruthenium), Group 9 (cobalt, rhodium, iridium), Group 10 (nickel, palladium, platinum), Group 11 (copper, silver, gold), Group 12 (zinc, cadmium) and Group 13 (aluminium, gallium, indium). Suitable metals of Group n of the periodic table further include metals of Group 3 (scandium, yttrium). Suitable metals of Group n+1 of the periodic table further include metals of Group 14 (germanium, tin). The conductive metal oxide may comprise zinc and aluminium. For example, the conductive metal oxide may comprise an aluminium-doped zinc oxide.

[0129] According to another embodiment the laser direct structuring additive may comprise calcium copper titanate. The thermoplastic resin may comprise a resin such as a polycarbonate in particular aromatic polycarbonate, polyamide, polyester, polyesteramide, polystyrene, polymethyl methacrylate, polyphenylene ether, liquid crystal polymer (LOP), polyether ether ketone (PEEK), cyclic olefin (co)polymer (COP) or combinations thereof. The resins may be homopolymers, copolymers or mixtures thereof, and may be branched or non-branched.

[0130] According to various embodiments a conductor track structure may be formed on a non-conductive supporting material (i.e. flexible substrate) comprising a metallized layer which is applied to metal nuclei created by breaking up very finely distributed non- conductive metal compounds contained in the flexible supporting material. The non- conductive metal compounds contained in the flexible supporting material may be broken up or otherwise activated by irradiating portions of the flexible supporting material with electromagnetic radiation. The non-conductive metal compounds may comprise thermally stable inorganic oxides which are stable and insoluble in aqueous acid or alkaline metallization baths, and which are selected from the group consisting of higher oxides which contain at least two different kinds of cations and which have a spinel structure or spinel-related structure, and which remain unchanged in nonirradiated areas of the flexible supporting material. Classic spinels are mixed metal oxides of magnesium and aluminium, but the magnesium may be wholly or partially replaced by iron, zinc and / or manganese, and the aluminium by iron and / or chromium. Spinel-related mixed oxide structures also may contain nickel and / or cobalt cations.

[0131] According to various embodiments a conductor track structure may be formed on a non-conductive support having at least a surface formed of a non-conductive supporting material having at least one thermally stable, spinel-based, non-conductive metal oxide which is stable and insoluble in aqueous acid or alkaline metallization baths dispersed therein. The process involves irradiating areas of the flexible support on which conductive tracks are to be formed with electromagnetic radiation to break down the non-conductive metal oxides and release metal nuclei, and subsequently metallizing the irradiated areas by chemical reduction. According to various embodiments non- conductive metal compounds of thermally highly stable inorganic oxides which are stable and insoluble in aqueous acid or alkaline metallization baths and which are higher oxides having the structure of spinels or structures that are similar to the spinel structures may be used. As a result these metal compounds may remain unchanged on the surface of the flexible supporting material even in non-irradiated areas. The inorganic oxides used may be resistant to heat so that they remain stable even after having been exposed to soldering temperatures i.e. they do not become electrically conductive and they remain stable in a bath used for metallization.

[0132] According to various embodiments the spinel or spinel-related structure may contain copper, chromium, iron, cobalt, nickel or a mixture of two or more of the foregoing. In particular the spinel or spinel-related structure may comprise copper.

[0133] The electrically non-conductive supporting material may comprise a thermoplastic or a thermosetting synthetic resin material. The non-conductive supporting material may contain one or more inorganic fillers e.g. silicic acid and / or silicic acid derivatives.

[0134] According to various embodiments a spinel-based thermally stable non- conductive higher oxide may be utilised which contains at least two different kinds of cations and which are stable and insoluble in aqueous acid or alkaline metallisation baths. The cations are mixed into the flexible supporting material and the flexible supporting material may then be processed into a component or may be applied to a component as a coating. During the process of laser direct structuring metal nuclei are released using electromagnetic radiation in the area of the conductor structures that are to be produced and these areas are then metallised by chemical reduction, the inorganic metal compound in the form of the spinel-based higher oxides can remain on the surface of the flexible supporting material in the non-irradiated areas. The inorganic higher oxides which contain at least two different kinds of cations used are furthermore sufficiently resistant to heat so that it is possible to use compounding or injection molding of modern high-temperature plastics.

[0135] Electromagnetic radiation may be used to simultaneously release metal nuclei and effect ablation while forming an adhesion-promoting surface. This provides a simple means to achieve excellent adhesive strength of subsequently deposited metallic conductor tracks. The inorganic oxides may contain copper, chromium, iron, cobalt, nickel or mixtures thereof. The non-conductive supporting material may comprise a thermoplastic or a thermosetting synthetic resin material. However, other embodiments are contemplated wherein the flexible supporting material may comprise a non-conductive material such as a ceramic. The non-conductive supporting material may contain one or more inorganic fillers e.g. silicic acid and / or silicic acid derivatives.

[0136] According to various embodiments a laser may be used to produce a beam of electromagnetic radiation which may be directed onto the surface of the flexible substrate in order to release metal nuclei at locations where the laser beam impinges upon the surface of the flexible substrate. The metal nuclei which are released effectively form a catalyst or anchor for the subsequent (optional) depositing of one or more conductive layers upon the laser activated regions by immersing the flexible substrate in a bath. The wavelength of the laser may be, for example, 248 nm, 308 nm, 355 nm, 532 nm, 1064 nm or 10600 nm.

[0137] It will be understood, that according to various embodiments it is not essential to deposit one or more conductive layers upon the laser activated regions. Instead, embodiments are contemplated wherein the resulting laser activated regions may comprise metal nuclei such as copper atoms which have essentially been liberated from the doped thermoplastic support. The metal nuclei forming the laser activated regions may have a depth < 1 pm or 1-10 pm and may form conductive traces or tracks on the surface of the flexible support.

[0138] At the first step, a laser beam may be directed onto portions of the flexible support . The laser activates the surface of the thermoplastic material of the flexible support so that metal nuclei are formed or liberated from the flexible support on the surface of the flexible support. The metal nuclei may form a thin surface layer having a thickness < 5 pm or < 1 pm. In addition to activating the additive in the flexible support in order to form a laser activated region comprising metal nuclei, the laser beam may also form a microroughened surface which assists with helping one or more layers of conductive material to anchor to the laser activated region during a subsequent optional metallisation step.

[0139] It is contemplated that the surface roughness of the surface of the conductive pattern may be in the range < 0.025 pm, 0.025-0.05 pm, 0.05-1 pm, 0.1-1 pm, 1-5 pm, 5-10 pm, 10-15 pm or > 15 pm. According to other embodiments the surface roughness may be in the range of < 0.1 pm, 0.1-1 pm, 1-10 pm, 10-20 pm, 20-30 pm, 30-40 pm, 40-50 pm or > 50 pm.

[0140] If the desired thickness of the electrode structure which is desired to be formed on the flexible support is greater than the thickness of the laser activated region formed at the first step with the laser structuring and activation process, an optional metallisation step can be used in order to further increase the thickness of the electrode structure which is formed upon the surface of the flexible support. Prior to carrying out a second step, the flexible support having a laser activated region formed therein may be cleaned. The flexible support can be cleaned by any suitable conventional process, including spraying with water-based, semi-aqueous or solvent-based cleaning solutions, or by ultrasonic cleaning methods which are known in the art. Once the cleaning the process is complete, a metallisation step may then be initiated, which may act to deposit one or more conductive layers onto the conductive tracks initially formed in the flexible support.

[0141] The metallisation step adds to the laser activated additive layer using an electroless metallisation process. The flexible support can be placed in a bath where electroless metallisation may be arranged to take place. The bath can, for example, comprise copper, nickel, silver, gold, chromium, palladium, tin, aluminium, platinum, tungsten or zinc. When placed in the bath, conductive tracks or traces formed on the flexible support may have their thickness increased at a rate in the range of 8-12 pm / h. This process can be carried out until a desired thickness of electrode structure is obtained.

[0142] It will be appreciated that each conductive layer can comprise the same conductive material e.g. copper or there a series layers may be deposited each comprising a different material selected from copper, nickel, silver, gold, chromium, palladium, tin, aluminium, platinum, tungsten or zinc. The one or more conductive layers which are deposited upon the laser activated regions may each have a thickness of: (i) < 10 pm; (ii) 10-20 pm; (iii) 20-30 pm; (iv) 30-40 pm; (v) 40-50 pm; (vi) 50-60 pm; (vii) GOO pm; (viii) 70-80 pm; (ix) 80-90 pm; or (x) 90-100 pm.

[0143] After the metallisation step is completed, a final (and optional) surface finish step may be carried out. In the final (optional) step, optional and application-specific coatings may be deposited on top of the built-up conductive tracks or electrodes using the same or similar electroless metallisation process as described above with reference to the second step. For example, the flexible substrate may be placed into a bath containing the desired coating. Coatings can include copper, nickel, silver, gold, chromium, palladium, tin, aluminium, platinum, tungsten or zinc.

[0144] Although the above second and final steps refer to electroless metallisation, other plating techniques are also contemplated, including a non-electrolytic plating, a galvanic plating or an autocatalytic plating process wherein the one or more laser activated regions may be contacted with a liquid solution so as to trigger a chemical or catalytic reaction that deposits metal particles present in the liquid solution onto the one or more laser activated regions so as to form the one or more conductive layers. The various embodiments described herein are presented only to assist in understanding and teaching the claimed features. These embodiments are provided as a representative sample of embodiments only, and are not exhaustive and / or exclusive. It is to be understood that advantages, embodiments, examples, functions, features, structures, and / or other aspects described herein are not to be considered limitations on the scope of the invention as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of, appropriate combinations of the disclosed elements, components, features, parts, steps, means, etc, other than those specifically described herein. In addition, this disclosure may include other inventions not presently claimed, but which may be claimed in future.

Claims

Claims1 . An aerosol provision device comprising: a magnetic field generator comprising a plurality of flexible substrates, wherein each substrate comprises one or more electrically conductive elements, wherein the plurality of substrates are deformed so as to form a substantially tubular element.

2. An aerosol provision device as claimed in claim 1 , wherein the substantially tubular element comprises one or more helical electrically conductive elements.

3. An aerosol provision device comprising: a magnetic field generator comprising a flexible substrate, wherein the substrate comprises one or more electrically conductive elements, wherein the substrate overlaps itself to form a substantially tubular element.

4. An aerosol provision device as claimed in claim 3, wherein the one or more electrically conductive elements comprise a plurality of electrically conductive tracks arranged to form a plurality of substantially parallel electrical paths.

5. An aerosol provision device as claimed in any preceding claim, wherein the or each substrate comprise an electrical insulator.

6. An aerosol provision device as claimed in any preceding claim, wherein the or each substrate comprises a polymer or a plastic.

7. An aerosol provision device as claimed in any preceding claim, wherein the or each substrate comprises polyimide (“Pl“).

8. An aerosol provision device as claimed in any preceding claim, wherein the or each substrate has a thickness of: (i) < 10 pm; (ii) 10-20 pm; (iii) 20-30 pm; (iv) 30-40 pm; (v) 40-50 pm; (vi) 50-60 pm; (vii) 60-70 pm; (viii) 70-80 pm; (ix) 80-90 pm; (x) 90- 100 pm; (xi) 100-200 pm; (xii) 200-300 pm; (xiii) 300-400 pm; (xiv) 400-500 pm; (xv) 500-600 pm; (xvi) 600-700 pm; (xvii) 700-800 pm; (xviii) 800-900 pm; (xix) 900-1000 pm; (xx) 1-2 mm; (xxi) 2-3 mm; (xxii) 3-4 mm; (xxiii) 4-5 mm; or (xxiv) > 5 mm.

9. An aerosol provision device as claimed in any preceding claim, wherein the one or more electrically conductive elements comprise a metal or metal alloy.

10. An aerosol provision device as claimed in any preceding claim, wherein the one or more electrically conductive elements comprise copper, nickel, silver, gold, chromium, palladium, tin, aluminium, platinum, tungsten, brass, bronze or zinc.

11. An aerosol provision device as claimed in any preceding claim, further comprising a magnetic shielding element.

12. An aerosol provision device as claimed in claim 11 , where the magnetic shielding element is arranged to surround at least a portion of the magnetic field generator.

13. An aerosol provision device as claimed in claim 11 or 12, wherein the magnetic shielding element comprises a ferromagnetic material.

14. An aerosol provision device as claimed in claim 13, wherein the ferromagnetic material comprises one or more from the group consisting of: (i) iron; (ii) nickel; and (iii) cobalt.

15. An aerosol provision device as claimed in any preceding claim, further comprising a heat insulation member.

16. An aerosol provision device as claimed in claim 15, where the heat insulation member is surrounded by at least a portion of the magnetic field generator.

17. An aerosol provision device as claimed in claim 15 or 16, wherein the heat insulation member comprises a ceramic or a plastic.

18. An aerosol provision device as claimed in any preceding claim, wherein the one or more electrically conductive elements have a thickness of: (i) < 10 pm; (ii) 10-20 pm; (iii) 20-30 pm; (iv) 30-40 pm; (v) 40-50 pm; (vi) 50-60 pm; (vii) 60-70 pm; (viii) 70-80 pm; (ix) 80-90 pm; (x) 90-100 pm; (xi) 100-200 pm; (xii) 200-300 pm; (xiii) 300-400 pm; (xiv) 400-500 pm; (xv) 500-600 pm; (xvi) 600-700 pm; (xvii) 700-800 pm; (xviii) 800-900 pm; (xix) 900-1000 pm; (xx) 1-2 mm; (xxi) 2-3 mm; (xxii) 3-4 mm; (xxiii) 4-5 mm; or (xxiv) > 5 mm.

19. An aerosol provision device as claimed in any preceding claim, wherein the one or more electrically conductive elements have a width of: (i) < 10 pm; (ii) 10-20 pm; (iii) 20-30 pm; (iv) 30-40 pm; (v) 40-50 pm; (vi) 50-60 pm; (vii) 60-70 pm; (viii) 70-80 pm; (ix) 80-90 pm; (x) 90-100 pm; (xi) 100-200 pm; (xii) 200-300 pm; (xiii) 300-400 pm; (xiv) 400- 500 pm; (xv) 500-600 pm; (xvi) 600-700 pm; (xvii) 700-800 pm; (xviii) 800-900 pm; (xix) 900-1000 pm; (xx) 1-2 mm; (xxi) 2-3 mm; (xxii) 3-4 mm; (xxiii) 4-5 mm; or (xxiv) > 5 mm.

20. An aerosol provision system comprising: an aerosol provision device as claimed in any preceding claim; and an aerosol generating article comprising aerosol generating material.

21. A method of manufacturing a magnetic field generator of an aerosol provision device comprising: providing a plurality of flexible substrates, wherein each substrate comprises one or more electrically conductive elements; and deforming the plurality of substrates so as to form a substantially tubular element.

22. A method of manufacturing a magnetic field generator of an aerosol provision device comprising: providing a flexible substrate, wherein the substrate comprises one or more electrically conductive elements; and deforming the substrate so that the substrate overlaps itself to form a substantially tubular element.

23. A method as claimed in claim 21 or 22, further comprising depositing, sputtering, laser direct activating, implanting, etching or printing the one or more electrically conductive elements on or onto the one or more substrates to provide the flexible substrate comprising the one or more electrically conductive elements.

24. A method of generating an aerosol comprising: providing an aerosol provision device comprising a magnetic field generator comprising a plurality of flexible substrates, wherein each substrate comprises one or more electrically conductive elements, wherein the plurality of substrates are deformed so as to form a substantially tubular element; inserting an aerosol generating article comprising aerosol generating material into the aerosol provision device; and activating the aerosol provision device.

25. A method of generating an aerosol comprising: providing an aerosol provision device comprising a magnetic field generator comprising a flexible substrate, wherein the substrate comprises one or more electrically conductive elements, wherein the substrate overlaps itself to form a substantially tubular element; inserting an aerosol generating article comprising aerosol generating material into the aerosol provision device; and activating the aerosol provision device.

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