Abstract
An aerosol-generating device for generating an aerosol by inductively heating an aerosol-forming substrate is provided, the device including: a device housing including a cavity to removably receive the substrate; an inductive heating arrangement including an induction coil configured to generate an alternating magnetic field within the cavity in a range between 500 kHz to 30 MHz, the coil being formed by a plurality of turns of a composite cable arranged around the cavity, the cable including a first side facing inward towards the cavity, a second side opposite to the first side facing outward away from the cavity, and an electrical conductor embedded in an insulating conductor encasement and including non-insulated wires in electrical contact with each other, and the conductor being arranged asymmetrically with regard to an outer cross-section of the cable to be closer to the first side than to the second side.
Claims
1.-15. (canceled)
16. An aerosol-generating device for generating an aerosol by inductively heating an aerosol-forming substrate, the aerosol-generating device comprising: a device housing comprising a cavity configured to removably receive at least a portion of the aerosol-forming substrate to be heated; an inductive heating arrangement comprising an induction coil configured to generate an alternating magnetic field within the cavity in a range between 500 kHz to 30 MHz, wherein the induction coil is formed by a plurality of turns of a composite cable arranged around at least a portion of the cavity, wherein the composite cable comprises a first side facing inward towards the cavity, a second side opposite to the first side facing outward away from the cavity, and an electrical conductor embedded at least partially in an insulating conductor encasement, wherein the electrical conductor comprises a plurality of non-insulated wires in electrical contact with each other, and wherein the electrical conductor is arranged asymmetrically with regard to an outer cross-section of the composite cable so as to be closer to the first side of the composite cable than to the second side of the composite cable.
17. The aerosol-generating device according to claim 16, wherein the non-insulated wires run parallel to each other along a length extension of the composite cable in a single layer, or wherein the non-insulated wires run parallel to each other along a length extension of the composite cable in a plurality of layers on top of each other.
18. The aerosol-generating device according to claim 17, wherein the single layer or each of the plurality of layers is a flat layer, or wherein the single layer or each of the plurality of layers is a curved layer.
19. The aerosol-generating device according to claim 16, wherein the composite cable has a substantially circular outer cross-section or a substantially non-circular outer cross-section.
20. The aerosol-generating device according to claim 16, wherein the composite cable has a substantially rectangular outer cross-section, or a substantially square outer cross-section, or a substantially elliptical outer cross-section, or a substantially oval outer cross-section, or a substantially parallelogram-shaped outer cross-section, or a substantially trapezoid outer cross-section, or a substantially arc-shaped outer cross-section.
21. The aerosol-generating device according to claim 16, wherein the composite cable is a flat cable, and/or wherein the electrical conductor is a flat conductor.
22. The aerosol-generating device according to claim 16, wherein the electrical conductor has a substantially rectangular outer cross-section, or a substantially square outer cross-section, or a substantially elliptical outer cross-section, or a substantially oval outer cross-section, or a substantially parallelogram-shaped outer cross-section, or a substantially trapezoid outer cross-section, or a substantially arc-shaped outer cross-section.
23. The aerosol-generating device according to claim 16, wherein the insulating conductor encasement comprises a magnetic flux concentrator material being a material or materials having a relative maximum magnetic permeability of at least 1000, for frequencies up to 50 kHz and a temperature of 25 degrees Celsius.
24. The aerosol-generating device according to claim 16, wherein the insulating conductor encasement comprises a magnetic flux concentrator material being a material or materials having a relative maximum magnetic permeability of at least 10000, for frequencies up to 50 kHz and a temperature of 25 degrees Celsius.
25. The aerosol-generating device according to claim 16, wherein the composite cable is a multi-layer composite cable comprising an electrically insulating conductor encasement layer forming the insulating conductor encasement, and at least one of a support layer, a flux concentrator layer, or a shield layer.
26. The aerosol-generating device according to claim 25, wherein the support layer comprises an electromagnetic inert material being at least one of polyetheretherketone or polyaryletherketone.
27. The aerosol-generating device according to claim 25, wherein the support layer is an edge layer forming the first side of the composite cable, and wherein one of the flux concentration layer or the shield layer is an edge layer forming the second side of the composite cable.
28. The aerosol-generating device according to claim 25, wherein the shield layer comprises an electrically conductive material being at least one of aluminum, copper, tin, steel, gold, silver, an electrically conductive polymer, a ferrite, or any combination thereof.
29. The aerosol-generating device according to claim 16, further comprising at least one susceptor arranged at least partially within the cavity.
30. An aerosol-generating system, comprising: an aerosol-generating device according to claim 16; and an aerosol-generating article received or receivable at least partially in the cavity of the device, the aerosol-generating article comprising the aerosol-forming substrate to be heated.
31. The aerosol-generating system according to claim 30, wherein the aerosol-generating article further comprises at least one susceptor positioned in thermal proximity to or thermal contact with the aerosol-forming substrate so that the at least one susceptor is inductively heatable by the inductive heating arrangement when the article is received in the cavity of the aerosol-generating device.
Description
[0152] Examples will now be further described with reference to the figures in which:
[0153] FIG. 1 shows a schematic longitudinal cross-section of an aerosol-generating system in accordance with a first embodiment the present invention;
[0154] FIG. 2 shows a schematic longitudinal cross-section of an aerosol-generating system in accordance with a second embodiment the present invention;
[0155] FIG. 3 shows a first embodiment of an induction module as used in the aerosol-generating system according to FIG. 1;
[0156] FIG. 4 shows a second embodiment of an induction module useable in an aerosol-generating system according to the present invention;
[0157] FIG. 5 shows a third embodiment of an induction module useable in an aerosol-generating system according to the present invention;
[0158] FIG. 6 shows a first embodiment of a composite cable as used in the aerosol-generating system according to FIG. 1;
[0159] FIG. 7 shows a second embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0160] FIG. 8 shows a third embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0161] FIG. 9 shows a fourth embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0162] FIG. 10 shows a fifth embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0163] FIG. 11 shows a sixth embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0164] FIG. 12 shows a seventh embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0165] FIG. 13 shows an eighth embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0166] FIG. 14 shows a ninth embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0167] FIG. 15 shows a tenth embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0168] FIG. 16 shows an eleventh embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0169] FIG. 17 shows a twelfth embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0170] FIG. 18 shows a thirteenth embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0171] FIG. 19 shows a fourteenth embodiment of a composite cable useable in an aerosol-generating system according to the present invention;
[0172] FIG. 20 shows a fifteenth embodiment of a composite cable useable in an aerosol-generating system according to the present invention; and
[0173] FIG. 21 shows a sixteenth embodiment of a composite cable useable in an aerosol-generating system according to the present invention.
[0174] FIG. 1 shows a schematic cross-sectional illustration of a first exemplary embodiment of an aerosol-generating system 1 according to the present invention. The system 1 is configured for generating an aerosol by inductively heating an aerosol-forming substrate 97. The system 1 comprises two main components: an aerosol-generating article 90 including the aerosol-forming substrate 97 to be heated, and an aerosol-generating device 10 for use with the article 90. The device 10 comprises a cavity 20 for receiving the article 90, and an inductive heating arrangement 30 for heating the substrate 97 within the article 90 when the article 90 is received in the cavity 20.
[0175] The article 90 has a rod shape resembling the shape of a conventional cigarette. In the present embodiment, the article 90 comprises four elements arranged in coaxial alignment: a substrate element 91, a support element 92, an aerosol-cooling element 94, and a filter plug 95. The substrate element is arranged at a distal end of the article 90 and comprises the aerosol-forming substrate to be heated. The aerosol-forming substrate 97 may include, for example, a crimped sheet of homogenized tobacco material including glycerin as an aerosol-former. The support element 92 comprises a hollow core forming a central air passage 93. The filter plug 95 serves as a mouthpiece and may include, for example, cellulose acetate fibers. All four elements are substantially cylindrical elements being arranged sequentially one after the other. The elements have substantially the same diameter and are circumscribed by an outer wrapper 96 made of cigarette paper such as to form a cylindrical rod. The outer wrapper 96 may be wrapped around the aforementioned elements so that free ends of the wrapper overlap each other. The wrapper may further comprise adhesive that adheres the overlapped free ends of the wrapper to each other.
[0176] The device 10 comprises a substantially rod-shaped main body 11 formed by a substantially cylindrical device housing 19. Within a distal portion 13, the device 10 comprises a power supply 16, for example a lithium ion battery, and an electric circuitry 17 including a controller for controlling operation of the device 10, in particular for controlling the heating process. Within a proximal portion 14 opposite to the distal portion 13, the device 10 comprises the cavity 20. The cavity 20 is open at the proximal end 12 of device 10, thus allowing the article 90 to be inserted into the cavity 20.
[0177] A bottom portion 21 of the cavity separates the distal portion 13 of the device 10 from the proximal portion 14, in particular from the cavity 20. Preferably, the bottom portion is made of a thermally insulating material, for example, PEEK (polyether ether ketone). Thus, electric components within the distal portion 13 may be kept separate from aerosol or residues produced by the aerosol generating process within the cavity 20.
[0178] The inductive heating arrangement 30 comprises an induction coil 31 for generating an alternating, in particular high-frequency magnetic field within the cavity 20. Preferably, the high-frequency magnetic field may be in the range between 500 kHz (kilo-Hertz) to 30 MHz (Mega-Hertz), in particular between 5 MHz (Mega-Hertz) to 15 MHz (Mega-Hertz), preferably between 5 MHz (Mega-Hertz) and 10 MHz (Mega-Hertz). In the present embodiment, the induction coil 31 is a helical coil circumferentially surrounding the cylindrical cavity 20 along its length axis. The induction coil 31 is formed by a plurality of turns of a composite cable 32 which comprises a multi-wire electrical conductor 33. Details of the composite cable 32 will be described further below, in particular with reference to FIG. 3-18.
[0179] The inductive heating arrangement 30 further comprises a susceptor 60 that is arranged within the cavity 20 such as to experience the magnetic field generated by the induction coil 31. In the present embodiment, the susceptor 60 is a susceptor blade 61. With its distal end 64, the susceptor blade is arranged at the bottom portion 21 of the cavity 20 of the device. From there, the susceptor blade 61 extends into the inner void of the cavity 20 towards the opening of the cavity 20 at the proximal end 12 of the device 10. The other end of the susceptor blade 60, that is, the distal free end 63 is tapered such as to allow the susceptor blade to readily penetrate the aerosol-forming substrate 97 within the distal end portion of the article 90.
[0180] Alternatively, as shown in FIG. 2, the susceptor 60 may be part of the aerosol-generating article 90. Here, the susceptor 99 is a susceptor strip made of a susceptive material that is embedded within the aerosol-forming substrate 97 of the article 90. The susceptor strip 99 is arranged such as to extend long the center of the substantially cylindrical article 90. Apart from that, the embodiment of the aerosol-generating system according to FIG. 2 is identical to the embodiment of the aerosol-generating system according to FIG. 1. Therefore, identical or similar features are denoted with identical reference numbers.
[0181] With reference to both embodiments, the inductive heating process is as follows: When the device 10 is actuated, a high-frequency alternating current is passed through the induction coil 31. Since the coil is arranged around the cavity 20, the alternating current through the coil causes an alternating magnetic field within the cavity 20. Depending on the magnetic and electric properties of the respective susceptor material, the alternating magnetic field induces at least one of eddy currents or hysteresis losses in the susceptor blade 61 or the susceptor strip 99, respectively. As a consequence, the susceptor blade 61 or the susceptor strip 99, respectively, is heated up until reaching a temperature that is sufficient to form an aerosol from the substrate 97 that is in thermal proximity or direct physical contact thereto. The generated aerosol may be drawn downstream through the aerosol-generating article 90 for inhalation by the user.
[0182] As can be seen in FIG. 1 and FIG. 2, the induction coil 31 is part of an induction module 40 that is arranged with the proximal portion 14 of the aerosol-generating device 10. The induction module 40 has a substantially cylindrical shape that is coaxially aligned with a longitudinal center axis 71 of the rod-shaped device 10. As can be seen from FIG. 1, the induction module 40 forms a least a portion of the cavity 20 or at least a portion of an inner surface of the cavity 20.
[0183] FIG. 3 shows the induction module 40 in more detail. Besides the induction coil 31, the induction module 40 comprises a tubular support sleeve 42 which carries the helically wound, cylindrical induction coil 31. At its inner surface, the tubular support sleeve 42 comprises an annular recess 41 in which the cylindrical induction coil 31 is received. Accordingly, both end portions 44 of the support sleeve 42 protrude radially inwards towards the center axis 71 such as to retain the induction coil 31 in position in the recess of the support sleeve 42. The support sleeve 42 may be made from any suitable material, such as a plastic. In particular, the support sleeve 42 may form a least a portion of the cavity 20, that is, at least a portion of an inner surface of the cavity 20.
[0184] FIG. 4 shows a second embodiment of the induction module 40. Here, the tubular support sleeve 42 comprises an annular recess 43 at its outer surface in order to receive the cylindrical induction coil 31 therein. Accordingly, both end portions 44 of the support sleeve 42 protrude radially outwards away from the center axis 71 such as to retain the induction coil 31 in position in the recess 43.
[0185] FIG. 5 shows a third embodiment of the induction module 40.The induction module 40 is nearly identical to the module according to FIG. 4. In addition, the induction module 40 of the third embodiment comprises a susceptor sleeve 69 42 that is surrounded by the induction coil 32. That is, the susceptor sleeve 69 is part of the aerosol-generating device but not of the aerosol-generating article. The susceptor sleeve 69 is arranged in an annular recess 45 at the inner surface of the support sleeve. Hence, the susceptor sleeve 69 forms at least a portion of an inner surface of the cavity 20. Accordingly, when an article is inserted in the cavity, the susceptor sleeve 69 surrounds the substrate element 91 in order to heat the aerosol-forming substrate from outside. In this configuration, the susceptor sleeve 69 acts an oven heater. This is in contrast to the embodiments shown in FIG. 1 and FIG. 2 where the susceptor blade 61 or the susceptor strip 99, respectively, heats the aerosol-forming substrate from inside.
[0186] FIG. 6 shows the composite cable 32 used to form the induction coil 31 of the devices 10 shown in FIG. 1 and FIG. 2 in more detail. The composite cable 32 comprises an electrical conductor 33 for carrying the current used to generate the magnetic field. The conductor 33 is fully embedded in an insulating conductor encasement 34 in order to electrically insulate adjacent turns of the induction coil from each other and thus to prevent a short circuit. According to the invention, the conductor 33 comprises a plurality of non-insulated wires 35 in electrical contact with each other. In the present embodiment, the conductor 33 comprises in total twenty-two wires 35 which are arranged in two layers on top of each other, wherein each layer comprises eleven wires 35. The layers are aligned such that wires 35 of one layer are arranged in grooves formed between adjacent wires 35 of the other layer. Accordingly, the assembly of all the wires 35 forms an electrical conductor 33 having a substantially trapezoid cross-section.
[0187] Each wire 35 may have a diameter in a range between 0.25 millimeter and 0.75 millimeter, for example 0.5 millimeter. Accordingly, the width dimension 33.1 of the electrical conductor 33 is given by eleven-and-half times the wire diameter. That is, the width dimension 33.1 of the electrical conductor 33 may be in range between 2.875 millimeter and 8.625 millimeter, for example 5.75 millimeter. Likewise, the thickness dimension 33.2 of the electrical conductor 33 is given by about 1.73 times the wire diameter. That is, the width dimension 33.1 of the electrical conductor 33 may be in range between about 0.4 millimeter and about 1.3 millimeter, for example about 6.5 millimeter. In the present embodiment, the width dimension of the electrical conductor 33 corresponds to a maximum dimension of the cross-section of the electrical conductor perpendicular to a radial direction 70 (see dashed-dotted arrow in FIG. 4-6) with respect to the plurality of turns of the composite cable. Likewise, the thickness dimension of the electrical conductor 33 corresponds to a maximum dimension of a cross-section of the electrical conductor 33 in a radial direction 70 (see dashed-dotted arrow in FIG. 4-6) with respect to the plurality of turns of the composite cable 32. As the width dimension 33.1 of the electrical conductor 33 is much larger than its thickness dimension 33.2, the electrical conductor 33 may be denoted as a flat electrical conductor 33.
[0188] The same holds for the entire cable 32 which also has a width dimension 32.1 that is much larger than its thickness dimension 32.2. Accordingly, the composite cable 32 may be denoted as a flat composite cable 32. In the present embodiment, the width dimension 32.1 of the composite cable 32, that is, a maximum dimension of the cross-section of the composite cable 32 perpendicular to a radial direction 70 (see dashed-dotted arrow in FIG. 4-6) with respect to the plurality of turns of the composite cable 32 31, may be in a range between 1 millimeter and 7 millimeter, in particular between 1.5 millimeter and 5 millimeter. Likewise, the thickness dimension 32.2 of the composite cable 32, that is, wherein a maximum dimension of the cross-section of the composite cable 32 in a radial direction 70 (see dashed-dotted arrow in FIG. 4-6) with respect to the plurality of turns of the composite cable, may be in a range between 0.5 millimeter and 9 millimeter, in particular between 0.7 millimeter and 9 millimeter, preferably between 0.9 millimeter and 5 millimeter. The outer cross-section of the composite cable 32 is substantially rectangular which rounded edges.
[0189] Upon being arranged around the cavity 20, the composite cable 32 comprises a first side 38 facing inwards towards the cavity 20 and a second side 39 opposite to the first side facing outwards away from the cavity 20. This is indicated in FIG. 6 which shows a section of the composite cable in the winding configuration. As can be further seen in FIG. 6, the electrical conductor 33 is arranged substantially symmetrically with respect to a first axis of symmetry 32.3 of the outer cross-section of the cable 32 which extends between the first side 38 and the second side 39 in the radial direction 70. In contrast, the electrical conductor 33 is arranged asymmetrically with regard to a second axis of symmetry 32.4 of the outer cross-section of the composite cable 32 such as to be closer to the first side 38 of the composite cable than to the second side 39. That is, the insulating conductor encasement 34 is mainly located towards the second side 39 of the composite cable and thus radially further outside than the electrical conductor 33. In particular, the electrical conductor 33 is arranged between the first side 38 and the second axis of symmetry. Due to this, the insulating conductor encasement 34 may act as a protective sheath surrounding the conductor 33 when the composite cable 32 is arranged around the cavity. Here, a minimum distance 33.8 between the conductor 33 and the first side 38 is at most in a range between 0.1 millimeter and 0.5 millimeter, in particular between 0.1 millimeter and 0.3 millimeter.
[0190] In addition, the insulating conductor encasement 34 may serve other purposes. In the present embodiment, the insulating conductor encasement 34 comprises a magnetic flux concentrator material in order to concentrate or focus the magnetic field within the cavity 20. Advantageously, this increases the level of heat generated in the susceptor for a given level of power passing through the induction coil 31 in comparison to induction coils having no flux concentrator. Thus, the efficiency of the aerosol-generating device 10 is improved. Furthermore, by distorting the magnetic field towards the cavity, the magnetic flux concentrator material of the insulating conductor encasement 34 reduces the extent to which the magnetic field propagates beyond the induction coil 31. That is, the flux concentrator material of the insulating conductor encasement 34 acts as a magnetic shield. Advantageously, this may reduce undesired interference of the magnetic field with other susceptive parts of the aerosol-generating device 10, for example with a metallic outer housing, or with susceptive external items in close proximity to the device 10. In particular, integrating a magnetic flux concentrator material in the composite cable 32 allows for providing both the induction coil 31 and an appropriate magnetic flux concentrator in one part. Advantageously, this reduces the effort required to manufacture the aerosol-generating device 10 both in terms of costs and time. As an example, the insulating conductor encasement 34 may comprise or may be made of a lamination, a pure ferrite or a proprietary iron- or ferrite based composition. Here, the insulating conductor encasement 34 is made of Alphaform MF available from Fluxtrol Inc., 1388 Atlantic Blvd. Auburn Hills, Mich. 48326 USA. Alphaform MF is formable soft magnetic composite developed on the basis of magnetic particles with a thermal-curing epoxy binder which is suitable or frequencies between 10 kilo-Hertz and 1000 kilo-Hertz.
[0191] Advantageously, the wires 35 of conductor 33 are embedded in the material of the insulating conductor encasement 34 by extrusion or lamination. FIG. 7 shows a second embodiment of the composite cable 32 which is very similar to the first embodiment of the composite cable 32 as shown in FIG. 6. Therefore, identical or similar features are denoted with identical reference numbers. In contrast to the first embodiment, the composite cable 32 according to FIG. 7 comprises a conductor 33 which consists of a single layer of seven wires 35. Each of the seven wires 35 has larger diameter than the wires 35 shown in FIG. 6. The diameter is chosen such that the cross-sectional area of the electrical conductor 33 in FIG. 7, that is, the sum of the cross-sectional areas of all seven wires 35, substantially corresponds to the cross-sectional area of the electrical conductor 33 in FIG. 6, that is, to the sum of the cross-sectional area of all twenty-two wires 35. Thus, the composite cable 32 shown in FIG. 6 and the composite cable 32 shown in FIG. 7 have substantially the same electrical properties, in particular substantially the same electrical resistance. However, the composite cable 32 according to FIG. 6 is more flexible due to the larger number and smaller diameter of the wires 35.
[0192] FIG. 8-10 show three further embodiments of the composite cable 132. In all three embodiments, the composite cable 132 is realized as a multi-layer composite cable 132 which comprises an electrically insulating conductor encasement layer 134 forming the insulating conductor encasement as described above and, addition to that, a support layer 136. Both layers 134, 136 fully enclose the electrical conductor 133. Advantageously, the different layers may be attached to each other by means of a lamination process.
[0193] The support layer 136 serves to increase the mechanical resistance of the composite cable 134. In order not to affect the induction performance of the magnetic field generated by the current through the electrical conductor 132, the support layer 136 is electromagnetically inert in all three embodiments. For example, the support layer 136 may be made of polyetheretherketone or polyaryletherketone, both of which are electromagnetic inert materials.
[0194] In all three embodiments, the respective support layer 136 is an edge layer, in particular an edge layer forming the first side 138 of the composite cable 132.
[0195] In the embodiments shown in FIGS. 8 and 9, the electrical conductor 133 is at least partially embedded in the respective support layer 136 and partially embedded in the insulating conductor encasement layer 134. Apart from the support layer 136 and the partial embedment in the insulating conductor encasement layer, the composite cables 132 shown in FIGS. 8 and 9 are very similar to the composite cables 32 shown in FIGS. 6 and 7, respectively. Therefore, identical or similar features are denoted with the same reference signs, yet incremented by 100. In contrast, in the embodiment shown in FIG. 10, the electrical conductor 133 is not embedded in the support layer 136. Instead, the support layer 136 covers that side of the electrical conductor 133 which faces inwards towards the cavity when the composite cable 132 is arranged around the cavity 20. Accordingly, the support layer 136 is thinner than the support layer 136 in FIGS. 8 and 9. Further in contrast to the embodiments shown in FIGS. 8 and 9, the insulating conductor encasement layer 134 of the cable 132 shown in FIG. 10 consists of three parts: a first part 134.1 arranged on a side of the conductor 133 opposite to the first side 138 as well as a second part 134.2 and a third part 134.3 arranged laterally to the narrow sides of the flat conductor 133. Furthermore, the composited cable 132 according to FIG. 10 does not have rounded edges, but rather sharp edges. In the embodiments according to FIGS. 8 and 9, the support layer 136 may have a layer thickness in a range between 0.1 millimeter and 1 millimeter, in particular between 0.2 millimeter and 0.5 millimeter. Likewise, in the embodiment according to FIG. 10, the support layer 136 may have a layer thickness in range between 0.25 millimeter and 1 millimeter, in particular between 0.25 millimeter and 0.5 millimeter.
[0196] The insulating conductor encasement layer 134 may have a total layer thickness in a range between 0.5 millimeter and 7 millimeter, in particular between 0.7 millimeter and 4 millimeter or between 0.7 millimeter and 3 millimeter, or in a range between 0.4 millimeter and 7.2 millimeter, in particular between 0.45 millimeter and 2.6 millimeter. Likewise, a portion of the insulating conductor encasement layer 134 embedding the conductor on a side opposite to the first side, in particular the first part 134.1, may have a thickness in a range between 0.2 millimeter and 5 millimeter, in particular 0.2 millimeter and 1.5 millimeter.
[0197] FIG. 11-13 show yet another three embodiments of the composite cable 232 which are similar to the embodiments shown in FIG. 8-10. Therefore, identical or similar features are denoted with the same reference signs, yet incremented by 100. In contrast to the embodiments shown in FIG. 8-10, the composite cables 232 shown in FIG. 11-13 additionally comprise a shield layer 237 arranged on top of the insulating conductor encasement layer 234 opposite to the support layer 236. The shield layer 237 primarily serves to reduce adverse effects of the magnetic field in regions outside the shield layer 237 and, vice versa, to reduce distortion of the magnetic field by electrically conductive or highly magnetically susceptible materials in the immediate vicinity of the device, or in the housing of the device itself. Accordingly, the shield layer 237 preferably comprises a conductive material, such as a metal coating applied on a side of the electrically insulating conductor encasement layer facing outwards away from the cavity. This can be further seen from FIG. 11-13, the respective shield layer 237 is an edge layer forming the second side 239 of the multi-layer composite cable 232.
[0198] The shield layer 237 may have a layer thickness in a range between 0.3 millimeter and 3 millimeter, in particular between 0.3 millimeter and 2 millimeter.
[0199] To compensate for the additional layer 237, the layer thickness of the insulating conductor encasement layer 234 in the embodiments shown in FIG. 11-13 may be different from the respective layer thicknesses in the embodiments shown in FIG. 8-10. Accordingly, the insulating conductor encasement layer of the embodiments shown in FIG. 11-13 may have a total layer thickness in a range between 0.2 millimeter and 6 millimeter, in particular between 0.4 millimeter and 2 millimeter, or in a range between 0.4 millimeter and 9.2 millimeter, in particular between 0.45 millimeter and 3.1 millimeter. Likewise, a portion of the insulating conductor encasement layer 234 embedding the conductor on a side opposite to the first side, in particular the first part 234.1, may have a thickness in a range between 0.2 millimeter and 7 millimeter, in particular 0.2 millimeter and 2 millimeter.
[0200] FIG. 14-16 show yet another three embodiments of the composite cable 332 which are similar to the embodiments shown in FIG. 11-13. Therefore, identical or similar features are denoted with the same reference signs, yet incremented by 100. In contrast to the embodiments shown in FIG. 11-13, the composite cables 332 shown in FIG. 14-16 comprises a flux concentrator layer 337, instead of a shield layer. For example, the flux concentrator layer 337 may comprise a ferrite material. The ferrite material acts as flux concentrator material. Furthermore, the layer thicknesses are slightly different to those of the embodiment shown in FIG. 11-13. Here, the insulating conductor encasement layer 334 of the embodiments shown in FIG. 14-16 may have a total layer thickness in range between 0.15 millimeter and 3 millimeter, in particular between 0.3 millimeter and 1 millimeter, or in a range between 0.45 millimeter and 3.7 millimeter, in particular between 0.5 millimeter and 2.85 millimeter. Likewise, a portion of the insulating conductor encasement layer 334 embedding the conductor on a side opposite to the first side, in particular the first part 334.1, may have a thickness in a range between 0.25 millimeter and 1.5 millimeter, in particular between 0.25 millimeter and 0.75 millimeter. The flux concentrator layer 337 may have a layer thickness in range between 0.25 millimeter and 5.5 millimeter, in particular between 0.25 millimeter and 1.75 millimeter.
[0201] As shown in FIG. 17, it is also possible that the composite cable 432 does not comprise a support layer, but only a shield layer 437 and an insulating conductor encasement layer 434 in which the conductor 433 is embedded. Alternatively, as shown in FIG. 18, it is also possible that the composite cable 532 only comprises a flux concentrator layer 537 and an insulating conductor encasement layer 534 in which the conductor 533 is embedded, but no support layer. In this configuration, the
[0202] As shown in FIG. 19 the composite cable 632 may also comprise a cross-section other than a substantially rectangular cross-section as shown in FIG. 1-18. In the present embodiment, the composite cable 632 has an arc-shaped cross-section. The cable 632 is also a multi-layer composite cable comprising a shield layer or a flux concentrator layer 637 and an insulating conductor encasement layer 634 in which a substantially arc -shaped conductor 633 is embedded. With regard to the arc-shaped cross-section, the width dimension of the composite is measured along the first side 638 or along the second side 639 or along a midline between the first side 538 and the second side 639 which is parallel to the first side 638 and the second side 539. Likewise, the thickness dimension may be measured in the radial direction along an axis normal to the first side 638 and the second side 639.
[0203] FIG. 20 shows another embodiment of a multi-layer composite cable 732 which is a combination of the composite cable according to FIGS. 11 and 14. The multi-layer composite cables 732 comprises a support layer 736, an insulating conductor encasement layer 734 on top of the support layer 736 in which a conductor 733 is embedded, a flux concentrator layer 737 on top of the insulating conductor encasement layer 734 and a shield layer 770 arranged on top of the flux concentrator layer 737 opposite to the support layer 736. The shield layer 770 may be, for example, a metallic coating on top of the flux concentrator layer 737.
[0204] As shown on FIG. 21, it is also possible to omit the support layer, like in FIG. 17 and FIG. 18. Accordingly, FIG. 21 shows yet another embodiment of a multi-layer composite cable 832 which is a combination of the composite cable according to FIGS. 17 and 18. The multi-layer composite cables 832 comprises a conductor 833 embedded in an insulating conductor encasement layer 834, a flux concentrator layer 837 on top of the insulating conductor encasement layer 834 and a shield layer 870 arranged on top of the flux concentrator layer 837.
[0205] In FIG. 14-16, FIG. 18 and FIG. 20-21, the respective insulating conductor encasement layer 334, 535, 734, 834 preferably does not comprise any flux concentrator material due to the presence of the respective additional flux concentrator layer 337, 537, 737 837. However, it is also possible that the respective insulating conductor encasement layer 334, 535, 734, 834 comprises a flux concentrator material in addition to the respective flux concentrator layer 337, 537, 737 837.
[0206] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term “about”. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A±5 percent of A.
