AEROSOL-GENERATING ARTICLE HAVING AN ADJUSTABLE HEATING AREA

Abstract

An aerosol-generating article is provided, including: an aerosol-forming substrate; and a heater assembly configured to heat the aerosol-forming substrate, the heater assembly including an array of heating elements, a plurality of the heating elements of the array each including at least one circuit-breaker component, and each of the circuit-breaker components being individually activatable to selectively deactivate an area of the heater assembly prior to heating such that, upon heating, the aerosol-generating article selectively heats a portion of the aerosol-forming substrate corresponding to a non-deactivated part of the heater assembly. A device for the aerosol-generating article, and an aerosol-generating system, are also provided.

Claims

1.-15. (canceled)

16. An aerosol-generating article, comprising: an aerosol-forming substrate; and a heater assembly configured to heat the aerosol-forming substrate, the heater assembly comprising an array of heating elements, wherein a plurality of the heating elements of the array each comprise at least one circuit-breaker component, and wherein each of the circuit-breaker components is individually activatable to selectively deactivate an area of the heater assembly prior to heating such that, upon heating, the aerosol-generating article selectively heats a portion of the aerosol-forming substrate corresponding to a non-deactivated part of the heater assembly.

17. The aerosol-generating article according to claim 16, wherein each of the circuit-breaker components comprises a fusible region, which is configured to melt at a predetermined temperature to break the heating element.

18. The aerosol-generating article according to claim 17, wherein the fusible region comprises metallic nanoparticles arranged to receive light from a light source and to generate heat by surface plasmon resonance to raise a temperature of the fusible region to the predetermined temperature.

19. The aerosol-generating article according to claim 17, wherein at least a proportion of the fusible regions are arranged to surround a predetermined area of the heater assembly to be deactivated.

20. The aerosol-generating article according to claim 18, further comprising a mask arranged to cover the heater assembly, wherein the mask comprises a pattern of holes or transparencies such that only fusible regions at locations corresponding to the locations of the holes or transparencies in the mask are activated when exposed to the light source.

21. A device for the aerosol-generating article of claim 16, wherein the device is configured to receive the aerosol-generating article, the aerosol-generating device comprising: control circuitry; and an activation device for activating one or more of the circuit-breaker components, wherein the control circuitry is configured to control the activation device to activate one or more of the circuit-breaker components when an aerosol-generating article is received in the device, such that a selected area of the heater assembly is deactivated prior to heating.

22. The device according to claim 21, wherein the activation device is a light source, and wherein the control circuitry is further configured to control the light source to expose one or more of the fusible regions to light when the aerosol-generating article is received in the device such that heat is generated in the fusible regions by surface plasmon resonance to raise a temperature of the fusible region to a predetermined temperature at which the fusible region melts to break the heating element.

23. The device according to claim 21, wherein the device is an aerosol-generating device further comprising a power source, and wherein the control circuitry is further configured to control a supply of power from the power source to the heater assembly when the aerosol-generating article is received in the device to selectively heat a portion of the aerosol-forming substrate corresponding to a non-deactivated part of the heater assembly.

24. An aerosol-generating system, comprising: an aerosol-forming substrate; and a heater assembly arranged to heat the aerosol-forming substrate, the heater assembly comprising an array of heating elements; a power source; an electronic switch for each of the heating elements, each electronic switch being connected to its respective heating element and the power source to control a flow of electrical current through the respective heating element; and control circuitry configured to control a supply of electrical current from the power source to the heater assembly by controlling the activation of each of the electronic switches individually such that an area of the heater assembly can be selectively activated during heating to heat a portion of the aerosol-forming substrate corresponding to the activated part of the heater assembly.

25. The aerosol-generating system according to claim 24, wherein the array of heating elements comprises a two-dimensional array of heating elements having a plurality of first heating elements extending in a first direction and a plurality of second heating elements extending in a second direction, wherein the second direction is transverse to the first direction such that the plurality of second heating elements intersect the plurality of first heating elements, and wherein the first and the second heating elements are electrically connected at their points of intersection.

26. The aerosol-generating system according to claim 25, wherein an area of the heater assembly is selectively activated by activating one of the electronic switches connected to a first heating element in combination with one of the electronic switches connected to a second heating element.

27. The aerosol-generating system according to claim 24, wherein the aerosol-forming substrate, the heater assembly, and the electronic switches form part of an aerosol-generating article, wherein the power source and the control circuitry form part of an aerosol-generating device configured to receive the aerosol-generating article, and wherein the aerosol-generating device comprises an electrical contact for each of the electronic switches, each electrical contact being arranged to electrically connect to its respective electronic switch when the aerosol-generating article is received in the aerosol-generating device.

28. The aerosol-generating system according to claim 24, wherein the aerosol-forming substrate forms at least part of an aerosol-generating article, and wherein the heater assembly, the electronic switches, the power source, and the control circuitry form part of an aerosol-generating device configured to receive the aerosol-generating article.

29. The aerosol-generating system according to claim 24, wherein each electronic switch comprises a transistor.

30. An aerosol-generating article according to claim 16, wherein the aerosol-forming substrate extends across the heater assembly and is divided into units, each unit corresponding to an activatable area of the heater assembly.

31. An aerosol-generating system according to claim 24, wherein the aerosol-forming substrate extends across the heater assembly and is divided into units, each unit corresponding to an activatable area of the heater assembly.

Description

[0096] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0097] FIG. 1 is a schematic plan view of an aerosol-generating article in accordance with an embodiment of the present invention.

[0098] FIG. 2 is a schematic side view of the aerosol-generating article of FIG. 1.

[0099] FIG. 3 is an enlarged view of a fusible region located at a point along the length of a heating element.

[0100] FIG. 4 is a schematic side view of a device in accordance with an embodiment of the present invention which device is configured to selectively activate the circuit-breaker components of the aerosol-generating article of FIG. 1 prior to heating.

[0101] FIG. 5 is a schematic side view of an aerosol-generating device in accordance with an embodiment of the present invention.

[0102] FIG. 6 is a schematic view of part an aerosol-generating system in accordance with an embodiment of the present invention showing part of a heater assembly and associated control circuitry.

[0103] FIG. 7A is a schematic view of part an aerosol-generating system in accordance with an embodiment of the present invention showing a heater assembly and the corresponding units of an aerosol-forming substrate which can be heated by the heater assembly.

[0104] FIG. 7B is an enlarged view of the bottom left-hand corner of the heater assembly shown in FIG. 7A.

[0105] FIG. 8 is a schematic plan view of an aerosol-generating system in accordance with an embodiment of the present invention comprising an aerosol-generating article and an aerosol-generating device for use with the aerosol-generating article. For clarity, the aerosol generating article is drawn to a larger scale than the aerosol-generating device.

[0106] FIG. 9 is a schematic plan view of an aerosol-generating system in accordance with another embodiment of the present invention comprising an aerosol-generating article and an aerosol-generating device for use with the aerosol-generating article. For clarity, the aerosol generating article is drawn to a larger scale than the aerosol-generating device.

[0107] FIG. 1 shows an aerosol-generating article 2 comprising an aerosol-forming substrate 4 and a heater assembly 6. The heater assembly 6 comprises a two-dimensional array or grid of heating elements comprising a plurality of first heating elements 6a extending in a first direction across the aerosol-forming substrate 4 and a plurality of second heating elements 6b extending in a second direction across the aerosol-forming substrate 4, which second direction is substantially orthogonal to the first direction such that the plurality of first heating elements 6a intersect the plurality of second heating elements 6b. The first 6a and second 6b heating elements are electrically connected at their points of intersection.

[0108] The heating elements 6a, 6b are electrically resistive heating elements which generate heat when an electrical current passes through them due to the Joule effect. In this embodiment, the heating elements 6a, 6b are formed of a Nickel-chrome (NiCr) alloy. The heater assembly 6 is in contact with the aerosol-forming substrate so that heat generated in the heating elements 6a, 6b is conducted and radiated into the aerosol-forming substrate 4 to cause a portion of the aerosol-forming substrate in the vicinity of a heating element to vaporise and form an aerosol.

[0109] The heater assembly 6 comprises fuse spots or fusible regions 8 which are located between the points of intersection of the first 6a and second 6b heating elements and can be individually activated to break the electrical circuit through the heating element 6a, 6b at the location of the fusible region 8. The fusible regions 8 therefore act as circuit-breaker components. In FIG. 1, five such fusible regions are shown which define an area A of the heater assembly 6 which is to be deactivated or electrically isolated from the rest of the heater assembly 6 prior to heating such that only the remaining non-deactivated part of the heater assembly 6 is heated during a subsequent heating operation. Consequently, only the portion of the aerosol-forming substrate corresponding to the non-deactivated part of the heater assembly 6 is vaporised. The fusible regions 8 can therefore be used to selectively adjust the area of the heater assembly 6 which is heated during a heating operation to selectively adjust the amount of aerosol generated.

[0110] The aerosol-generating article 2 also comprises a pair of electrical contact pads 10; one for connecting to the positive terminal of an electrical power source and the other for connecting to the negative or ground terminal of an electrical power source. The electrical contact pads 10 are arranged to connect to a pair of corresponding electrical contacts in an aerosol-generating device so that power can be supplied to the heater assembly 6. In use, an electrical current flows the heater assembly 6 between the electrical contacts 10 to generate heat in the heating elements 6a, 6b.

[0111] Referring to FIG. 2, this shows a side view of the aerosol-generating article 2 of FIG. 1. As can be seen from FIGS. 1 and 2, the aerosol-forming substrate 4 is formed as a tablet having a first major surface 4a and an opposing second major surface 4b. The thickness T of the aerosol-forming substrate is small relative to the length and width of the aerosol-forming substrate 4. Any suitable aerosol-forming substrate 4 could be used. For example, the aerosol-forming substrate 4 could be a solid tablet comprising tobacco cast leaves or the aerosol-forming substrate 4 could comprise a polymer or metallic foam which is impregnated with a liquid or gel or a combination of both containing one or more additives such as aerosol formers, nicotine and flavourings. The heater assembly 6 is in contact with the first major surface 4a of the aerosol-forming substrate 4.

[0112] FIG. 3 shows an enlarged view of one of the fusible regions 8 located along the length of one of the first heating elements 6a of FIG. 1. The fusible region 8 is formed of a thin wire of a low resistance electrical material, such as an alloy of zinc and aluminium, that is configured to melt at a predetermined temperature, which is above the temperature to which the heater is heated during normal operation. The thin wire is coated with gold nanoparticles (not shown). The thin wire of the fusible region 8 is approximately five times thinner than the heating element 6a and has a diameter or thickness of approximately 0.1 mm compared to a diameter of approximately 0.5 mm for the heating element 6a. It will be appreciated that in other embodiments the thin wire of the fusible region may be even thinner relative to the heating elements, such as up to ten times thinner or more. In these embodiments, the thin wire may have a diameter of between about 0.05 mm and about 0.1 mm, compared to a heating element diameter of between about 0.1 mm and about 0.5 mm.

[0113] Due to the low resistance of the fusible region 8, it does not melt when the heater assembly is heated normally, i.e. when electrical power is supplied to the heater assembly to generate aerosol. However, due to the presence of the gold nanoparticles, the fusible regions 8 are sensitive to a physical phenomenon called surface plasmon resonance which can be used to melt the fusible regions 8. When the fusible regions 8 are irradiated with light at a wavelength which is comparable to the size of the nanoparticle, the free electrons of the nanoparticles are excited and a coherent oscillation of those electrons takes place. In order to relax to their initial state, the nanoparticle loses its surplus energy in the form of heat. Therefore, when the nanoparticle is exhibiting surface plasmon resonance, thermal energy is generated. For gold nanoparticles, the light wavelength should be approximately 530 nm (i.e. green light). This can raise the temperature of the fusible region up to 500 degrees centigrade. This is above the melting temperature of the thin wire of the fusible region 8 and causes the fusible region 8 to melt and break. Consequently, the electrical circuit through the heating element is broken at the location of the fusible region 8. By activating i.e. melting, selected fusible regions 8, an area of the heater assembly 6 can be deactivated or electrically isolated from the heating process.

[0114] Referring to FIG. 4, this shows a device 20 for selectively activating the fusible regions 8 (not shown in FIG. 4) of the aerosol-generating article 2 of FIG. 1 prior to heating of the heater assembly 6. The device 20 comprises a housing 22 enclosing a mount 24 for holding the aerosol-generating article 2 and a directional light source 26. The mount 24 is arranged to receive the aerosol-generating article 2 in a configuration in which the heater assembly 6 faces the directional light source 26. The mount 24 is sized and shaped to receive the aerosol-generating article with a tight fit such that the aerosol-generating article is held firmly and does not move relative to the mount 24. The aerosol-generating article 2 is shaped such that it is longer in one dimension than it is in another, so that it can only be received within the mount 24 in the correct orientation. Accordingly, the device 20 is able to determine the position of the aerosol-generating article 2 and the heater assembly 6 relative to the mount 24.

[0115] The directional light source 26 comprises a laser diode or a light emitting diode which is capable of emitting highly directional light at the required wavelength to achieve plasmon surface resonance in the fusible regions. The directional light source 26 is mounted on actuators (not shown) so that it can move relative to the mount 24. The actuators are controlled by control circuitry (not shown). The beam of light 28 emitted by the directional light source can be scanned over the surface of the heater assembly 6 and directed at individual fusible regions. This activates the fusible regions such that they exhibit surface plasmon resonance. The directional light source 26 therefore acts as an activation device for activating the fusible regions. The heat generated by surface plasmon resonance causes the fusible region to melt and break the electrical circuit at the location of the fusible region. By activating the fusible regions a selected area of the heater assembly 6 can be deactivated.

[0116] The device 20 can therefore be used prior to heating to selectively adjust the area of the heater assembly 6 which will be available for heating during a subsequent heating operation. Once the device 20 has adjusted the area of the heater assembly 6, the aerosol-generating article 2 can be removed from the device 20 and inserted into an aerosol-generating device. Upon heating, the aerosol-generating article 2 which generate an amount of aerosol proportional to the non-deactivated area of the heater assembly 6.

[0117] FIG. 5 shows a handheld electrically-operated aerosol-generating device 40 in which a light source for selectively adjusting the area of the heater assembly of the aerosol-generating article is contained within the device. The device comprises a housing 42 containing a power source 44, control circuitry 46 and a space 48 for receiving the aerosol-generating article 2 of FIG. 1. In FIG. 5, an aerosol-generating article 2 has been received within the device and the contact pads 10 of the aerosol-generating article 2 engage corresponding contact pins 50 of the device 40. The contact pins 50 are connected to the control circuitry 46, which controls the supply of electrical power to the heater assembly of aerosol-generating article 2.

[0118] A light source 52 is arranged such that it 52 faces the heater assembly of the aerosol-generating article 2 in order to direct light at the heater assembly. The light source 52 is a light emitting diode and is spaced from the heater assembly such that it can expose the entire area of the heater assembly when it is illuminated. A mask 54 is attached to the aerosol-generating article 2 such that it covers the heater assembly and is arranged between the light source 52 and the aerosol-generating article 2.

[0119] The mask 54 is made from an opaque material such as a metal foil and has a low-tack pressure sensitive adhesive arranged on one surface. The adhesive is used to adhere it temporarily to the aerosol-generating article 2 but allows the mask to be removed without leaving a residue. The mask 54 has holes 56 corresponding to the location of fusible regions on the heater assembly which are to be activated. The opaque material of the mask 54 protects the fusible regions which are not to be activated from the light emitted by light source 52, whereas the holes 56 allow light to pass through the mask 54 to the fusible regions to activate them. The mask 54 can therefore be used to selectively adjust the area of the heater assembly prior to heating.

[0120] The light source 52 is controlled by a switch 58 connected to the control circuitry 46. The switch 58 can be operated by a user to cause the light source to illuminate and expose the heater assembly to light through the mask 54. A further switch 60 is provided for activating the heater assembly.

[0121] The device 40 further comprises an air inlet 62 arranged in the housing, upstream of the space 48 for receiving the aerosol-generating article 2, and an air outlet 64 arranged in a mouthpiece 66 downstream of the space 48 for receiving the aerosol-generating article 2. The device 40 provides an airflow pathway between the air inlet 62 and air outlet 64 which flows past the heater assembly of aerosol-generating article 2 when an aerosol-generating article is received within the device 40.

[0122] In use, a user places an aerosol-generating article 2 having a mask 54 covering its heater assembly within the device 40 and operates switch 58. This causes the light source 52 to illuminate and expose the mask 54 with light. An area of the heater assembly of the aerosol-generating article 2 is deactivated corresponding to the pattern of holes in the mask 54. The mask 54 is then removed from the aerosol-generating article 2 and when a user is ready to take a puff from the device 40, they place the mouthpiece 66 to their lips and press switch 60. This activates the heater assembly of the aerosol-generating article 2 which heats a portion of aerosol-forming substrate corresponding to the non-deactivated part of the heater assembly causing a predetermined amount of aerosol to be generated. The user then draws the aerosol into their mouth via air outlet 64.

[0123] FIG. 6 is a schematic view of part an aerosol-generating system according to another embodiment of the present invention. The aerosol-generating system comprises a heater assembly 106 comprising a two-dimensional array or grid of heating elements. The two-dimensional array of heating elements comprises a plurality of first heating elements 106a extending in a first direction and a plurality of second heating elements 106b extending in a second direction, which second direction is substantially orthogonal to the first direction such that the plurality of first heating elements 106a intersect the plurality of second heating elements 106b. The first 106a and second 106b heating elements are electrically connected at their points of intersection. In FIG. 6, only two of the first heating elements 106a and only two of the second heating elements 106b are shown.

[0124] The first 106a and second 106b heating elements are coated with an aerosol-forming forming substrate, which, for the purposes of clarity, has been omitted from FIG. 6. Any suitable aerosol-forming substrate may be used. For example, the heating elements 106a, 106b may be coated with a solid aerosol-forming substrate comprising tobacco granules or particles. Alternatively, the heating elements 106a, 106b may be coated with a gel-type aerosol-forming substrate comprising one or more additives such as nicotine, flavourings and aerosol formers.

[0125] Each of the heating elements in the first direction 106a and each of the heating elements in the second direction 106b is connected to a separate transistor Ta, Tb, T1 and T2, respectively. In the embodiment of FIG. 6, bipolar transistors are used and the following description uses the terminology for bipolar transistors. However, it will be appreciated that other types of transistor can be used, for example, field-effect transistors.

[0126] The first heating elements 106a are connected to the emitter of their respective transistor Ta, Tb. The collectors of transistors Ta and Tb are connected to the positive terminal of a power source 102. The second heating elements 106b are connected to the collector of their respective transistor T1, T2. The emitters of transistors T1 and T2 are connected to the negative or ground terminal of the power source 102. The bases of all the transistors Ta, Tb, T1 and T2 are connected to control circuitry 104, which may include one or more microcontrollers.

[0127] The control circuitry 104 controls the supply of electrical current to the bases of transistors Ta, Tb, T1 and T2. When an electrical current is allowed to flow to the base of a transistor Ta, Tb, T1 and T2, the transistor is switched on. The transistors Ta, Tb, T1 and T2 therefore act as electronic switches which control the flow of current through their respective heating elements 106a, 106b. The control circuitry 104 controls the supply of electrical current from the power source to the heater assembly by controlling the activation of each of the transistors Ta, Tb, T1 and T2 individually such that an area of the heater assembly 106 can be selectively activated during heating to heat a portion of the aerosol-forming substrate (not shown) corresponding to the activated part of the heater assembly. For example, in FIG. 6, if the control circuitry 104 activates transistors Ta and T1, this causes an electrical current to flow from the positive terminal of the power source 102 via the collector of transistor Ta to the emitter of transistor T1 and back to the negative or ground terminal of the power source 102 and results in the area A of the heater assembly 106 (denoted by a dotted outline in FIG. 6) to be heated. This arrangement therefore allows the amount of aerosol generated to be controlled. A new part of the heater assembly 106 is activated each time the user takes a puff. This arrangement also allows multiple areas of the heater assembly to be successively activated to generate the required amount of aerosol, for example, by activating transistor Ta and transistor T1 and then activating transistor Ta and T2, etc.

[0128] FIG. 7A is a schematic view of the complete heater assembly 106 of the aerosol-generating system of FIG. 6. The heater assembly 106 comprises a two-dimensional array of heating elements comprising a plurality of first heating elements 106a extending in a first direction and a plurality of second heating elements 106b extending in a second direction, which is substantially orthogonal to the first direction. Each heating element 106a, 106b is connected to its own transistor (not shown in FIG. 7A but denoted by reference numerals Ta, Tb, Tc, etc. and T1, T2, T3 . . . Tn, etc.). The transistors Ta, Tb, Tc, T1, T2, T3 . . . Tn, etc. control the flow of electrical current through their respective heating elements 106a, 106b. The heating elements 106a, 106b are coated with an aerosol-forming substrate, which, has been omitted from FIG. 7A for the purposes of clarity. Any suitable aerosol-forming substrate may be used and examples are provided above in the description of FIG. 6.

[0129] The aerosol-forming substrate is divided into units A1, A2, which units define the amount of aerosol-forming substrate which can be individually heated by a pair of transistors. The amount of aerosol-forming substrate within each unit is configured such that the amount of aerosol generated by each unit is known. The amount of aerosol generated by a single unit is less than the amount of aerosol required for one puff or draw and is preferably a fraction of the amount of aerosol required for one puff or draw. The aerosol-generating system therefore successively or simultaneously heats a determined number of units to fulfil the aerosol quantity selected for a user's puff or draw.

[0130] For example, if the embodiment of FIG. 7A were to successively heat units of aerosol-forming substrate, the aerosol-generating system could firstly activate transistors Ta and T1 to make a first electric circuit which heats unit A1. It could then activate transistors Ta and T2 to make a second electric circuit which heats unit A2. Indeed, it could heat all of the units of aerosol-forming substrate along the heating element 106a connected to transistor Ta by activating transistor Ta and successively activating transistors T1 to Tn. The process could then be repeated for all of the units of aerosol-forming substrate along the heating element 106a connected to transistor Tb by activating transistor Tb and successively activating transistors T1 to Tn and so on.

[0131] FIG. 7B is an enlarged view of the bottom left-hand corner of FIG. 7A showing the units A1, A2 of aerosol-forming substrate which can be individually heated by a pair of transistors in more detail. Unit A1 of the aerosol-forming substrate corresponds to the activation of transistors Ta and T1 and Unit A2 of the aerosol-forming substrate corresponds to the activation of transistors Ta and T2.

[0132] As can be seen from FIG. 7B, during the successive heating of units of aerosol-forming substrate, some areas of the heater assembly 106 which have already been activated are activated again when adjacent areas are activated. For example, area A1′, which is part of unit A1 is activated when transistors Ta and T1 are activated and is activated again when transistors Ta and T2 are activated. However, area A1′ has already been depleted of aerosol-forming substrate during the activation of transistors Ta and T1. Therefore the effective area of unit A2 is the area of A2 minus the area A1′. Accordingly, the effective area of unit A2 is similar to the area of unit A1. The two-dimensional array of heating elements 106a, 106b consequently results in the aerosol-forming substrate being divided up into approximately equally sized units. This makes scaling up the amount of aerosol generated more straightforward. For example, if a situation requires twice as much aerosol as is generated with one unit, the aerosol-generating system can simply heat two units.

[0133] FIG. 8 shows an aerosol-generating system comprising an aerosol-generating article 200 and an aerosol-generating device 300 for use with the aerosol-generating article 200. For clarity, the aerosol generating article is drawn to a larger scale than the aerosol-generating device.

[0134] The aerosol-generating article 200 comprises an aerosol-forming substrate 204 and a heater assembly 206 which are both held within a support 208. The heater assembly 206 comprises a two-dimensional array of heating elements 206a, 206b and is configured in the same way as the heater assemblies of FIGS. 6 and 7A. That is, each heating element 206a, 206b is connected to a transistor (not shown) which controls the flow of electrical current through its respective heating element 206a, 206b. The aerosol-generating article 200 further comprises a plurality of electrical contacts 210 arranged around its periphery for connecting to the transistors and heating elements 206a, 206b. The electrical contacts 210 are arranged to connect to corresponding electrical contacts 310 within the aerosol-generating device 300.

[0135] In the embodiment of FIG. 8, the transistors (not shown) are located on or within the support 208 of the aerosol-generating article 200 between the electrical contacts 210 and the heating elements 206a, 206b. However, in other embodiments, the transistors could be part of the device 300, for example, the transistors could be located between the control circuitry 306 and the electrical contacts 310.

[0136] The aerosol-generating device 300 comprises a housing 302 containing a power source 304, control circuitry 306 and a space 308 for receiving the aerosol-generating article 200. As mentioned above, the aerosol-generating device 300 comprises electrical contacts 310 for connecting to the corresponding electrical contacts 210 of the aerosol-generating article 200. The electrical contacts 310 are arranged around the periphery of the recess 308 and are each connected to the control circuitry 306. For the purposes of clarity, FIG. 8 shows the connections between the control circuitry 306 and the electrical contacts 310 for only four of the electrical contacts 310.

[0137] The control circuitry 306 controls the supply of electrical power to the heater assembly 206 of aerosol-generating article 200. The control circuitry 306 comprises a wireless communication module (not shown) and a memory (not shown). The wireless communication module allows information relating to the user and the type of aerosol-generating article 200 to be transmitted to the aerosol-generating device 300. This information will include, for example, the amount of aerosol or aerosol components to generate for a particular user and the type of aerosol-forming substrate being heated. This information is then stored in the memory and, based on this information, the control circuitry 306 is able to determine what area of the heater assembly 206 of the aerosol-generating article 200 to activate. The aerosol-generating device also comprises a switch 316 which is connected to the control circuitry and which is operated by a user to activate the heater assembly 206 of the aerosol-generating article 200 when the aerosol-generating article 200 is received within the device 300.

[0138] The device 300 further comprises an air inlet (not shown) arranged in the housing 302 upstream of the recess 308 for receiving the aerosol-generating article 200 and an air outlet 312 arranged in a mouthpiece 314 downstream of the recess 308 for receiving the aerosol-generating article 2. The device 300 provides an airflow pathway between the air inlet and air outlet 312 which flows past the heater assembly 206 of the aerosol-generating article 200 when the aerosol-generating article 200 is received within the device 300.

[0139] In use, a user places an aerosol-generating article 200 in the aerosol-generating device 300 and when the user is ready to take a puff from the device 300, they place the mouthpiece 314 to their lips and press switch 316. This activates a selected area of the heater assembly 206 of the aerosol-generating article 200 to heat a portion or a certain number of units of the aerosol-forming substrate 204 corresponding to the required amount of aerosol to be generated. The user then draws the aerosol into their mouth via air outlet 312.

[0140] FIG. 9 shows an aerosol-generating system comprising an aerosol-generating article 400 and an aerosol-generating device 500 for use with the aerosol-generating article 400. For clarity, the aerosol generating article is drawn to a larger scale than the aerosol-generating device. The aerosol-generating system of FIG. 9 differs from that of FIG. 8 in that the heater assembly 507 is not located in the aerosol-generating article 400 but in the device 500. However, the aerosol-generating system of FIG. 9 uses the same principle of operation as that of FIG. 8.

[0141] The aerosol-generating article 400 comprises an aerosol-forming substrate 404 which is shaped like a tablet and is configured to be received within a correspondingly-shaped recess 508 in the aerosol-generating device 500. Any suitable aerosol-forming substrate 204 can be used. For example, the aerosol-forming substrate 404 could be a solid tablet comprising tobacco cast leaves or the aerosol-forming substrate 404 could comprise a polymer or metallic foam which is impregnated with a liquid or gel or a combination of both containing one or more additives such as aerosol formers, nicotine and flavourings.

[0142] The aerosol-generating device 500 comprises a housing 502 containing a power source 504, control circuitry 506 and a recess 508 for receiving the aerosol-generating article 400. As mentioned above, the recess 508 is shaped to receive the aerosol-generating article 400.

[0143] A heater assembly 507 is arranged in the base of the recess 508. The heater assembly 507 comprises a two-dimensional array of heating elements 507a, 507b and is configured in the same way as the heater assemblies of FIGS. 6, 7A and 9. That is, each heating element 507a, 507b is connected to a transistor (not shown) which controls the flow of electrical current through its respective heating element 507a, 507b. The transistors for the heating elements 507a, 507b are each connected to the control circuitry 506. For the purposes of clarity, FIG. 9 omits the transistors and only shows connections between the heating elements 507a, 507b and the control circuitry 506. Again, for the purposes of clarity, only four of the connections are shown.

[0144] The control circuitry 506 controls the supply of electrical power to the heater assembly 507. The control circuitry 506 comprises a wireless communication module (not shown) and a memory (not shown). The wireless communication module allows information relating to the user and the type of aerosol-generating article 400 to be transmitted to the aerosol-generating device 500. This information will include, for example, the amount of aerosol or aerosol components to generate for a particular user and the type of aerosol-forming substrate being heated. This information is then stored in the memory and, based on this information, the control circuitry 506 is able to determine what area of the heater assembly 507 to activate. The aerosol-generating device also comprises a switch 516 which is connected to the control circuitry and which is operated by a user to activate the heater assembly 507 when the aerosol-generating article 400 is received within the device 500.

[0145] The device 500 further comprises an air inlet (not shown) arranged in the housing 502 upstream of the recess 508 for receiving the aerosol-generating article 400 and an air outlet 512 arranged in a mouthpiece 514 downstream of the recess 508 for receiving the aerosol-generating article 400. The device 500 provides an airflow pathway between the air inlet and air outlet 512 which flows past the aerosol-generating article 400 when the aerosol-generating article 400 is received within the device 500.

[0146] In use, a user places an aerosol-generating article 400 in the aerosol-generating device 500 and when the user is ready to take a puff from the device 500, they place the mouthpiece 514 to their lips and press switch 316. This activates a selected area of the heater assembly 507 to heat a portion or a certain number of units of the aerosol-forming substrate 404 of the aerosol-generating article 400 corresponding to the required amount of aerosol to be generated. The user then draws the aerosol into their mouth via air outlet 512.