AEROSOL-GENERATING DEVICE AND SYSTEM WITH RESIDUE DETECTOR

Abstract

An aerosol-generating device is provided, including: a cavity configured to receive an aerosol-generating article including an aerosol-forming substrate; a heater configured to heat the aerosol-forming substrate received in the cavity; a power supply; a residue detector for sensing aerosol-forming substrate residue in the cavity or on the heater; and a controller configured to: control a supply of power from the power supply to the heater to heat the aerosol-forming substrate received in the cavity, receive signals from the residue detection means indicative of an amount of aerosol-forming substrate residue in the cavity or on the heater, and determine an indication of the amount of aerosol-forming substrate residue in the cavity or on the heater based on one or more signals received from the residue detection means. An aerosol-generating system and a residue detector device are also provided.

Claims

1.-15. (canceled)

16. An aerosol-generating device, comprising: a cavity configured to receive an aerosol-generating article comprising an aerosol-forming substrate; a heater configured to heat the aerosol-forming substrate received in the cavity; a power supply; residue detection means for sensing aerosol-forming substrate residue in the cavity or on the heater; and a controller configured to: control a supply of power from the power supply to the heater to heat the aerosol-forming substrate received in the cavity, receive signals from the residue detection means indicative of an amount of aerosol-forming substrate residue in the cavity or on the heater, and determine an indication of the amount of aerosol-forming substrate residue in the cavity or on the heater based on one or more signals received from the residue detection means.

17. The aerosol-generating device according to claim 16, wherein the controller is further configured to prevent power from being supplied from the power supply to the heater to heat aerosol-forming substrate in the cavity when the determined indication exceeds a threshold.

18. The aerosol-generating device according to claim 16, wherein the heater is an elongate heater configured to be inserted into the aerosol-generating article when the aerosol-generating article is received within the cavity, and the heater comprises a resistive heating element.

19. The aerosol-generating device according to claim 18, wherein the residue detection means comprises a configuration of the controller, such that the controller is further configured to: measure a resistance of the resistive heating element, and determine an indication of the amount of aerosol-forming substrate residue in the cavity or on the heater based on the measured resistance of the resistive heating element.

20. The aerosol-generating device according to claim 19, wherein the controller is further configured to: supply power from the power supply to the heater for heating the aerosol-forming substrate received in the cavity, terminate the supply of power to the heater and, after a predetermined time, measure the resistance of the resistive heating element of the heater, and determine the indication of the amount of aerosol-forming substrate residue on the heater based on resistance measurements of the resistive heating element.

21. The aerosol-generating device according to claim 19, wherein the determination of the indication of the amount of aerosol-forming substrate residue in the cavity is based on a rate of change of measurements of the resistance of the resistive heating element.

22. The aerosol-generating device according to claim 19, wherein the controller is further configured to: determine a characteristic of a puff of a user from measurements of the resistance of the heating element, and determine the indication of the amount of aerosol-forming substrate residue in the cavity or on the heater based on the determined characteristic of the puff of the user.

23. The aerosol-generating device according to claim 22, wherein the determined characteristic of the puff of the user is one or more of a volume of the puff and a duration of the puff, and wherein the determination of the indication of the amount of aerosol-forming substrate residue in the cavity or on the heater is based on a change in the determined characteristic of the puff of the user over time.

24. The aerosol-generating device according to claim 16, wherein the residue detection means comprises a residue detector disposed at or around the cavity.

25. The aerosol-generating device according to claim 24, wherein the determination of the indication of the amount of aerosol-forming substrate residue in the cavity is based on signals received from the residue detector at least a predetermined period of time after termination of a supply of power from the power supply to the heater.

26. The aerosol-generating device according to claim 24, wherein the residue detector comprises at least one of: a volatile organic compound (VOC) detector, an optical detector, a capacitor, and an acoustic detector.

27. The aerosol-generating device according to claim 26, wherein the residue detector comprises an optical detector, and wherein the optical detector comprises a light source configured to direct light into the cavity and a light sensor configured to receive light from the cavity.

28. An aerosol-generating system, comprising: an aerosol-generating device comprising: a device cavity configured to receive an aerosol-generating article comprising an aerosol-forming substrate, a heater configured to heat the aerosol-forming substrate received in the cavity, a device power supply, and a device controller configured to control a supply of power from the device power supply to the heater to heat the aerosol-forming substrate received in the device cavity; and a case configured to receive the aerosol-generating device, the case comprising: a case cavity configured to receive the aerosol-generating device, a residue detector configured to sense aerosol-forming substrate residue in the device cavity or on the heater when the aerosol-generating device is received in the case cavity, and a case controller configured to: receive signals from the residue detector indicative of an amount of aerosol-forming substrate residue in the device cavity or on the heater, and determine an indication of the amount of aerosol-forming substrate residue in the device cavity or on the heater based on signals received from the residue detector.

29. The aerosol-generating system according to claim 28, wherein the case controller is further configured to: compare the determined indication of the amount of aerosol-forming substrate residue in the device cavity or on the heater to a threshold, and send a cleaning signal to the device controller when the determined indication of the amount of aerosol-forming substrate residue in the device cavity or on the heater exceeds the threshold, and the device controller is further configured to: supply power to the heater to raise a temperature of the heater to a first temperature for heating the aerosol-forming substrate received in the cavity sufficiently for an aerosol to be formed, receive cleaning signals from the case controller, and supply the power to the heater to raise the temperature of the heater to a second temperature, higher than the first temperature, to thermally liberate organic materials adhered to or deposited in the cavity or on the heater when a cleaning signal is received from the case controller.

30. A residue detector device for detecting aerosol-forming substrate residue in an aerosol-generating device, the residue detector device comprising: a residue detector cavity configured to receive at least a portion of an aerosol-generating device; a residue detector configured to sense aerosol-forming substrate residue on the portion of the aerosol-generating device received in the residue detector cavity; and a controller configured to: receive signals from the residue detector indicative of an amount of aerosol-forming substrate residue on the portion of the aerosol-generating device received in the residue detector cavity, and determine an indication of the amount of aerosol-forming substrate residue on the portion of the aerosol-generating device received in the residue detector cavity based on signals received from the residue detector.

Description

[0158] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0159] FIG. 1 shows a schematic illustration of an aerosol-generating device in accordance with an embodiment of the present invention;

[0160] FIG. 2 shows an exemplary relationship between resistance of a heating element of the aerosol-generating device of FIG. 1 over time with different amounts of aerosol-forming substrate disposed on a surface of the heater;

[0161] FIG. 3 shows a schematic illustration of an aerosol-generating device in accordance with another embodiment of the present invention;

[0162] FIG. 4 shows a schematic illustration of a capacitive residue detector of the aerosol-generating device of FIG. 3;

[0163] FIG. 5 shows a schematic illustration of a heater and optical residue detector of an aerosol-generating device according to another embodiment of the present invention;

[0164] FIG. 6 shows a schematic illustration of a heater assembly having light guides according to another embodiment of the present invention;

[0165] FIG. 7 shows a schematic illustration of an aerosol-generating system comprising a case and an aerosol-generating device according to another embodiment of the present invention;

[0166] FIG. 8 shows a schematic illustration of a portion of an aerosol-generating system comprising a case and an aerosol-generating device according to another embodiment of the present invention; and

[0167] FIG. 9 shows a schematic illustration of a residue detector device in cooperation with an aerosol-generating device according to another embodiment of the present invention.

[0168] FIG. 1 shows a schematic illustration of an aerosol-generating device 100 according to a first embodiment of the present invention. The aerosol-generating device 100 shown in FIG. 1 is a device configured to receive an aerosol-generating article (not shown) comprising a solid aerosol-forming substrate and a filter wrapped together in the form of a rod like a conventional cigarette. The aerosol-generating device 100 is a portable device that is configured to be held in the hand of a user. The aerosol-generating device 100 comprises a housing 102, which is generally cylindrical, having a length of about 90 mm, a diameter of about 14 mm.

[0169] An open, cylindrical cavity 104 is provided at a proximal end of the housing 102 of the device 100 for receiving aerosol-forming substrate of an aerosol-generating article. An elongate heater 106, in the form of blade, extends into the cavity 104 for penetrating into the aerosol-forming substrate of an aerosol-generating article received in the cavity 104. The heater 106 comprises a plurality of resistive heating elements or tracks disposed on an electrically insulating Polyimide substrate.

[0170] A power supply 108, in the form of a lithium-ion battery with a capacity of about 120 milliampere-hours, is housed within the housing 102.

[0171] A controller 110 is also housed within the housing 102. The controller 110 comprises a microprocessor (not shown). The controller 110 is connected to the heater 106 and the power supply 108, and the controller 110 is configured to control the supply of power from the power supply 108 to the heater 106.

[0172] In this embodiment, the controller 110 is configured to measure the resistance of one of the electrically resistive heating elements of the heater 106. The electrical resistance of the electrically resistive heating element provides an indication of the temperature of the heater 106. The controller 110 is configured to control the temperature of the heater 106 by controlling the power supplied from the power supply 108 to the heater 106 based on measurements of resistance of the electrically resistive heating element.

[0173] An electrical connector 112 is arranged at a distal end face of the housing 102, opposite the cavity 104. The power supply 108 and the controller 110 are connected to the electrical connector 112.

[0174] In accordance with the present invention, the aerosol-generating device 100 comprises residue detection means. In this embodiment, the residue detection means comprise the heater 106 and a configuration of the controller 110. The controller is configured to measure the electrical resistance of the electrically resistive heating element of the heater 106 a predetermined period of time after termination of a supply of power to the heater 106 for heating aerosol-forming substrate. In this device, the predetermined period of time is 30 seconds, which has been found to provide a reasonable length of time approximate to the time taken for a user to remove an aerosol-generating article from a device after use, and for lingering aerosol generated during use to disperse from the cavity.

[0175] After the predetermined period of time, the controller 110 is configured to supply a predetermined power to the heater 106 to raise the temperature of the heater by a nominal amount. The controller 110 is further configured to measure the resistance of the electrically resistive heating element and determine the rate of change of the resistance of the electrically resistive heating element as the temperature of the heater 106 is raised by the nominal amount. In this embodiment, the controller 110 is configured to monitor the rate of change of resistance of the heating element and compare the measured rate of change to a threshold. The threshold is a predetermined threshold that is stored in a memory (not shown) of the controller 110. If the rate of change of resistance is below the threshold, this provides an indication that an unacceptable amount of aerosol-forming substrate residue is present on the heater, and is negatively affecting the performance of the heater.

[0176] FIG. 2 shows an exemplary graph depicting exemplary changes in resistance of the electrically resistive heating element of the heater 106 over time for a given power supplied to the heater 106 when three different amounts of aerosol-forming substrate residue are provided on a surface of the heater 106. As shown in FIG. 2, the highest rate of change of resistance 150 of the heating element is measured when no aerosol-forming substrate residue is provided on a surface of the heater 106. A slightly lower rate of change of resistance 152 of the heating element is measured when a thin covering of aerosol-forming substrate residue is provided on a surface of the heater 106. The lowest rate of change of resistance 154 of the heating element is measured when a thick covering of aerosol-forming substrate residue is provided on a surface of the heater 106. A predetermined threshold 156 for the rate of change or resistance of the heating element is also shown in FIG. 2. The predetermined threshold delimits the lowest acceptable rate of change of resistance, which indicates the largest amount of aerosol-forming substrate residue that is acceptable on the heater.

[0177] Referring back to FIG. 1, the aerosol-generating device 100 further comprises a residue indicator 114, in the form of an LED arranged on an outer surface of the housing 102. In this embodiment, the controller 110 is configured to illuminate the LED 114 when the measured rate of change of resistance of the heating element is determined to be below the threshold value 156. The residue indicator LED 114 provides an indication to a user that the amount of aerosol-forming substrate residue in the cavity and on the heater is above an acceptable level, and the heater 106 requires cleaning.

[0178] It will be appreciated that in some embodiments, the controller may be configured to prevent power from being supplied to the heater to heat aerosol-forming substrate when the measured rate of change of resistance of the heating element is determined to be below the threshold value.

[0179] FIG. 3 shows a schematic illustration of an aerosol-generating device 200 according to a second embodiment of the present invention. The aerosol-generating device 200 is substantially similar to the aerosol-generating device 100 shown in FIG. 1, and like reference numerals are used to refer to like features. The aerosol-generating device 200 shown in FIG. 3 is configured to receive an aerosol-generating article (not shown) comprising a solid aerosol-forming substrate and a filter wrapped together in the form of a rod like a conventional cigarette. The aerosol-generating device 200 is a portable device that is configured to be held in the hand of a user. The aerosol-generating device 200 comprises a housing 202, which is generally cylindrical, having a length of about 90 mm, a diameter of about 14 mm.

[0180] An open, cylindrical cavity 204 is provided at a proximal end of the housing 202 of the device 200 for receiving aerosol-forming substrate of an aerosol-generating article. An elongate heater 206, in the form of blade, extends into the cavity 204 for penetrating into the aerosol-forming substrate of an aerosol-generating article received in the cavity 204. The heater 206 comprises a plurality of resistive heating elements or tracks disposed on an electrically insulating Polyimide substrate.

[0181] The cavity 204 is substantially cylindrical, having a circular base 205 and a tubular sidewall extending from the periphery of the base 205 to the open end of the cavity 204. The heater 206 extends into the cavity through the base 205.

[0182] A power supply 208, in the form of a lithium-ion battery with a capacity of about 120 milliampere-hours, is housed within the housing 202.

[0183] A controller 210 is also housed within the housing 202. The controller 210 comprises a microprocessor (not shown). The controller 210 is connected to the heater 206 and the power supply 208, and the controller 210 is configured to control the supply of power from the power supply 208 to the heater 206.

[0184] An electrical connector 212 is arranged at a distal end face of the housing 202, opposite the cavity 204. The power supply 208 and the controller 210 are connected to an electrical connector 212.

[0185] In accordance with the present invention, the aerosol-generating device 200 comprises residue detection means. In this embodiment, the residue detection means comprises a residue detector 218. The residue detector 218 is a capacitive sensor, as shown in FIG. 4.

[0186] The capacitive sensor 218 comprises a pair of annular electrodes 220, 222 disposed on the base 205 of the cavity 204. The annular electrodes 220, 222 are arranged concentrically and circumscribe the heater 206. The annular electrodes 220, 222 are interdigitated electrodes, each electrode having a plurality of protrusions that are regularly spaced apart and arranged such that the protrusions of one electrode extend into the spaces between the protrusions of the other electrode.

[0187] A first annular electrode 220 comprises a plurality of protrusions 221 extending radially outwards from an annular main track. The protrusions 221 of the first electrode 220 are spaced apart to provide regular spaces between adjacent protrusions 221. A second annular electrode 222 comprises a plurality of protrusions 223 extending radially inwards from an annular main track. The protrusions 223 of the second electrode 222 are spaced apart to provide regular spaces between adjacent protrusions 223. The number of protrusions 221 of the first electrode 220 is the same as the number of protrusions 223 of the second electrode 222. The protrusions 221 of the first electrode 220 are substantially identical to the protrusions 223 of the second electrode 222, having the same length and width. The protrusions 221 of the first electrode 220 extend into the spaces between adjacent protrusions 223 of the second electrode 222, and the protrusions 223 of the second electrode 222 extend into the spaces between adjacent protrusions 221 of the first electrode 220.

[0188] The first electrode 220 and the second electrode 222 are spaced apart by a generally constant spacing around the circumference of the electrodes. The second electrode 220 has a diameter substantially equal to the diameter of the base 205 of the cavity 204, such that the second electrode substantially circumscribes the base 205 of the cavity 204. In this arrangement, the capacitive residue sensor 218 is arranged to sense aerosol-forming substrate residue at the periphery of the base 205 of the cavity 204.

[0189] The controller 210 is configured to supply an alternating voltage to the first electrode 220, such that the first electrode 220 is configured as a driving electrode. The controller 210 is further configured to measure the voltage at the second electrode 222, such that the second electrode 222 is configured as a sensing electrode. The controller 210 is further configured to use the voltage measured at the second electrode 222 to determine the capacitance of the capacitor formed by the first and second electrodes 220, 222.

[0190] When an oscillating voltage is supplied to the first electrode 220, an electric field is established between the first and second electrodes 220, 222, across the space between the electrodes. The electric field between the first and second electrodes 220, 222 comprises a fringing field that extends out from the base 205 and into the cavity 204. The fringing field impinges on aerosol-forming substrate residue disposed on the base 205 of the cavity 204, above and in the vicinity of the capacitive sensor 218. The capacitance of the capacitor formed by the first and second electrodes 220, 222 is changed when the fringing field impinges on aerosol-forming substrate residue disposed on the base 205 of the cavity 204, as a result of the dielectric properties of the aerosol-forming substrate residue, and in turn the voltage at the second electrode 223 measured by the controller 210 is changed. The amount of aerosol-forming substrate residue on the base 205 of the cavity 204 is related to the magnitude of the change of the capacitance of the capacitive residue sensor 218. Accordingly, the capacitance of the capacitive residue sensor 218 may provide an indication of the amount of aerosol-forming substrate residue on the base 205 of the cavity 204.

[0191] In this embodiment, the aerosol-generating device 200 further comprises an indicator in the form of a buzzer 214 for providing an audible warning to a user when it is determined that the amount of aerosol-forming substrate residue in the cavity 204 is above an acceptable level.

[0192] The aerosol-generating device 200 comprises a switch 215, which may be pressed by a user to prompt the controller 210 to measure the capacitance of the capacitive residue sensor 218 and to determine an indication of the amount of aerosol-forming substrate residue is in the cavity 204. The controller 210 is configured to compare the determined capacitance of the capacitive residue sensor 218 to a predetermined threshold. When the determined capacitance exceeds the predetermined threshold, the controller determines that the amount of aerosol-forming substrate residue in the cavity 204 is above an acceptable level. Accordingly, when the determined capacitance exceeds the predetermined threshold, the controller 210 is configured to send a signal to the buzzer 214 to activate the buzzer 214 to warn the user that the cavity 204 requires cleaning.

[0193] In this embodiment, the controller 210 is further configured to prevent power from being supplied to the heater 206 when the determined capacitance exceeds the predetermined threshold. As such, a user is required to clean the cavity 204 before being able to use the aerosol-generating device again. Once the cavity 204 has been cleaned, the user is required to press the button 215 a second time, such that the controller 210 determines the amount of aerosol-forming substrate residue in the cavity 204 for a second time. If the controller 210 determines that the amount of aerosol-forming substrate residue in the cavity is within the acceptable level, the controller 210 is configured to enable the supply of power from the power supply 208 to the heater 206 for heating aerosol-forming substrate.

[0194] In this embodiment, the capacitive residue sensor is disposed on the base of the cavity. However, it will be appreciated that in other embodiments a capacitive residue sensor may be arranged on one or more sidewalls of the cavity. The first and second electrodes may have interdigitated protrusions extending on a sidewall of the cavity, in a direction between a proximal end and distal end of the cavity. Such a capacitive sensor disposed on a sidewall of a cavity may be configured to sense aerosol-forming substrate residue on or in the vicinity of the sidewall of the cavity.

[0195] FIG. 5 shows the proximal end of an aerosol-generating device 300 according to another embodiment of the present invention. The aerosol-generating device 300 is substantially similar to the aerosol-generating device 100 shown in FIG. 1, and like reference numerals are used to refer to like features. The aerosol-generating device 300 shown in FIG. 5 is configured to receive an aerosol-generating article (not shown) and comprises a housing 302, which is generally cylindrical, having a length of about 90 mm, a diameter of about 14 mm. An open cavity 304 is provided at a proximal end of the housing 302 for receiving the aerosol-forming substrate of an aerosol-generating article. An elongate heater 306, in the form of blade, extends into the cavity 304 for penetrating into the aerosol-forming substrate of an aerosol-generating article received in the cavity 304. The heater 306 comprises a plurality of resistive heating elements or tracks disposed on an electrically insulating Polyimide substrate.

[0196] The cavity 304 is substantially cylindrical, having a circular base 305. The heater 306 extends into the cavity 304 through a slot in the base 305.

[0197] In this embodiment, the housing 302 comprises an extractor 303 at the proximal end of the device 300. The extractor 303 defines the cavity 304, and is removably receivable on a distal portion of the housing 302. The extractor 303 comprises substantially tubular sidewalls and a base portion that extends inwards from the tubular sidewalls to define the base 305 of the cavity 304. The base portion comprises a slot for receiving the heater 306 when the extractor is received on the distal portion of the housing 302. The extractor 303 is configured to facilitate removal of an aerosol-generating article from the heater 306. Removal of the extractor 303 from the distal portion of the housing 302, in a proximal direction, removes an aerosol-generating article received in the cavity 304 from the heater 306.

[0198] A power supply (not shown), in the form of a lithium-ion battery with a capacity of about 120 milliampere-hours, is housed within the housing 302.

[0199] A controller 310 is also housed within the housing 302. The controller 310 comprises a microprocessor (not shown). The controller 310 is connected to the heater 306 and the power supply, and the controller 310 is configured to control the supply of power from the power supply to the heater 306.

[0200] In accordance with the present invention, the aerosol-generating device 300 comprises residue detection means. In this embodiment, the residue detection means comprises an optical residue detector. The optical residue detector comprises a light source 320, in the form of an LED configured to emit substantially white light, and a light sensor 322, in the form of a photodiode. The LED 320 and the photodiode 322 are mounted to opposite sides of the controller 310, such that the LED 320 and the photodiode 322 are positioned at opposite sides of the device 300.

[0201] The optical residue detector further comprises a pair of light guides 324, 326. The pair of light guides 324, 326 are arranged at opposite sides of the extractor 303, in distal portions of the extractor 303 that overlap with the distal portion of the housing 302 when the extractor 303 is received on the distal portion of the housing 302.

[0202] A first light guide 324 is arranged to align with the LED 320 when the extractor 303 is received on the distal portion of the housing 302. The first light guide 324 directs light from the LED into the cavity 304, substantially along the surface of the base 305 of the cavity 304.

[0203] A second light guide 326 is arranged to align with the photodiode 326 when the extractor 303 is received on the distal portion of the housing 302. The second light guide 326 directs light from the cavity 304 to the photodiode 326, particularly from the base 305 of the cavity 304.

[0204] In this arrangement, the optical residue detector is configured to direct light with a broad spectrum of wavelengths into the cavity 304, substantially along the base of the cavity 304, and to direct light out of the cavity 304 to the photodiode 322. Accordingly, the optical residue detector is configured to detect the presence of aerosol-forming substrate residue in the cavity 304, particularly at the base 305 of the cavity 304.

[0205] The controller 310 of the aerosol-generating device 300 is configured to determine an indication of the amount of aerosol-forming substrate residue in the cavity 304 and on the heater 306 from measurements of the intensity of light incident on the photodiode 322. The controller 310 is generally configured to use such residue determinations in a similar manner to the controller 210 of the device 200 described above and shown in FIG. 4.

[0206] FIG. 6 shows a heater assembly 400 for an aerosol-generating device according to another embodiment of the present invention. In this embodiment, the heater assembly 400 comprises a plurality of resistive heating elements 402 disposed on an electrically insulating Polyimide substrate 404. The electrically insulating substrate 404 and resistive heating elements 402 are formed into an elongate heating blade that is configured for insertion into an aerosol-forming substrate. A proximal end of the electrically insulating substrate 404 is tapered to a point to facilitate insertion of the heater into an aerosol-forming substrate.

[0207] In accordance with the present invention, the heater assembly 400 comprises a pair of light guides 424, 426 for an optical residue detector. The light guides 424, 426 are configured similarly to the light guides 324, 326 of the device 300 described above and shown in FIG. 5. The light guides 424, 426 are arranged to extend along a distal portion of the electrically insulating substrate 404, on which the resistive heating elements 402 are not disposed. The distal portion of the electrically insulating substrate 404 and the light guides 424, 426 are over-moulded with a high temperature plastics material to secure the light guides 424, 426 to the electrically insulating substrate 404, and to provide a mount 405 for securing the heater assembly 400 to the housing of an aerosol-generating device.

[0208] When the heater assembly 400 is arranged in an aerosol-generating device, a first light guide 424 is arranged to direct light from a light source of an optical residue detector of the device into the cavity of the device at the base of the cavity, and a second light guide 246 is arranged to direct light from the base of the cavity of the device to a photodetector of the optical residue detector of the device. The heater assembly arrangement shown in FIG. 4 may provide a straightforward, reliable and relatively inexpensive way to provide an aerosol-generating device with an optical residue detector.

[0209] FIG. 7 shows an aerosol-generating system comprising a case 500 according to another embodiment of the present invention. FIG. 7 also shows the aerosol-generating device 100 described above and shown in FIG. 1 received in the case 500.

[0210] The case 500 shown in FIG. 7 is a portable charging case having a case housing 502 that is shaped and sized to be held in a hand of a user and to fit into a pocket of a user's clothing. The housing 502 is generally a rectangular cuboid having a length of about 20 mm, a width of about 50 mm and a height of about 110 mm.

[0211] The case housing 502 defines a case cavity 504 for receiving an aerosol-generating device. In FIG. 7, the aerosol-generating device 100 of FIG. 1 is received in the case cavity 504. The case cavity 504 is open at a proximal end of the case housing 502 to receive an aerosol-generating device and is closed at a distal end of the case housing 502, opposite the proximal end. A lid 505 is rotatably attached to the proximal end of the case housing 502, via a hinge, and is configured to be rotated relative to the case housing 502 between an open position and a closed position. When the lid 505 is in the closed position, the lid 505 is arranged to cover the open end of the case cavity 504. In the closed position, the case housing 502 and the lid 505 substantially surround or enclose the aerosol-generating device 100, when the aerosol-generating device 100 is received in the case cavity 504. When the lid 505 is in the open position, the open end of the case cavity 504 is uncovered and the aerosol-generating device 100 may be inserted into the case cavity 504 and removed from the case cavity 504.

[0212] A case power supply 506, in the form of a lithium-ion battery with a capacity of about 2900 milliampere-hours (mAh), is housed within the case housing 502.

[0213] An electrical connector 508 is arranged at the closed distal end of the case cavity 504 for receiving the aerosol-generating device 100. The electrical connector 508 is connected to the case power supply 506 and is arranged to electrically connect with the corresponding electrical connector 112 of the aerosol-generating device 100 when the aerosol-generating is fully received in the chamber 504.

[0214] A case controller 510 is also housed within the case housing 502. The case controller 510 is connected to the case power supply 506 and to the electrical connector 508 and is configured to control the supply of power from the case power supply 506 to the electrical connector 508.

[0215] The case controller 510 and electrical connector 508 are configured to supply electrical power to the aerosol-generating device 100 received in the case cavity 504, and are also configured to communicate with the aerosol-generating device 100, to transfer data to the aerosol-generating device 100 and to receive data from the aerosol-generating device 100.

[0216] The case controller 510 comprises a microprocessor (not shown) and also comprises a communication interface (not shown), which in this embodiment comprises a telemetry circuit and an antenna for bidirectional communication with an external device or server. In this embodiment, the communication interface is a wireless interface using Bluetooth® protocol to communicate with an extremal device or server. Typically, the communication interface is configured to communicate with a user's smartphone.

[0217] In accordance with the present invention, the case 500 comprises a residue detector 518. The residue detector 518 is arranged on the lid 505 of the case 500, directly above the proximal end of the case cavity 504. In this position, the residue detector 518 is arranged over the open end of the device cavity 104 of the aerosol-generating device 100 when the aerosol-generating device 100 is received in the case cavity 504 and the lid 505 is in the closed position.

[0218] In some embodiments, the lid 505 of the case 500 may comprises a protrusion arranged to be received in the device cavity 504 when the aerosol-generating device 100 is received in the case cavity 504 and the lid 505 is in the closed position. In these embodiments, the residue detector 518 may be arranged on the protrusion.

[0219] In this embodiment, the residue detector 518 is a VOC detector. Accordingly, volatile organic compounds evolved from aerosol-forming substrate residue in the device cavity 104 or on the heater 106 may be detected by the VOC detector 518 of the case 500. The residue detector 518 is electrically connected to the case controller 510 via a flexible circuit (not shown). The flexible circuit enables a robust electrical connection between the residue detector 518 and the case controller 510, while also permitting rotation of the lid 505 relative to the case housing 502.

[0220] The case controller 510 is configured to take readings from the residue detector 518 a predetermined period of time after the lid 505 is moved into the closed position. In this embodiment, the predetermined period of time is ten seconds. The case controller 510 is configured to determine an indication of the amount of residue in the device cavity 104 or on the heater 106 based on one or more readings from the residue detector. Specifically, in this embodiment the case controller 510 is configured to compare one or more readings from the residue detector 518 to a predetermined threshold. When the one or more readings from the residue detector 518 exceed the predetermined threshold, the case controller 510 is configured to determine that the amount of aerosol-forming substrate residue in the device cavity 104 and on the heater 106 is above an acceptable level. When the one or more readings from the residue detector 518 exceed the predetermined threshold, the case controller 510 is configured to initiate a cleaning cycle in the aerosol-generating device 100.

[0221] When the one or more readings from the residue detector 518 exceed the predetermined threshold, the case controller 510 is configured to send a cleaning signal to the device controller 110 of the aerosol-generating device 100, over a communications link, via the electrical connectors 508, 112.

[0222] In this embodiment, the device controller 110 is configured to receive a cleaning signal from the case controller 510. When the device controller 110 receives a cleaning signal from the case controller 510, the device controller 110 is configured to supply power to the heater 106 in a cleaning cycle. In the cleaning cycle, the device controller 110 supplies power to the heater to raise the temperature of the heater sufficiently to thermally liberate organic materials adhered to or deposited in the device cavity 104 or on the heater. 106.

[0223] After each determination of the indication of the amount of residue in the device cavity 104 or on the heater 106, the case controller 510 is further configured to output a residue signal based on the determination to the communication interface of the case controller 510. The communication interface is configured to communicate the residue signal to a user's smartphone over a communications link using Bluetooth® protocol.

[0224] It is envisaged that a program may be stored on the user's smartphone for analysing residue information in the residue signal. In some embodiments, the program stored on the user's smartphone may not be configured to analyse the data received in the residue signal, but rather may be configured to forward the data or the signal to an external server, such as a cloud server for analysis.

[0225] In some embodiments, the case 500 may further comprises a graphical display at an outer surface of the case housing 502. The case controller 510 may be further configured to display residue amount information based on the determined indication to a user on the display.

[0226] In some embodiments, the case controller may not be configured to initiate residue detection a predetermined period of time after the lid is moved into the closed position, but rather a switch may be provided on the case for a user to actuate to initiate residue detection. In these embodiments, a user may determine when to initiate residue detection and a cleaning cycle.

[0227] FIG. 8 shows a proximal portion of an aerosol-generating system comprising a case 600 according to another embodiment of the present invention, and the aerosol-generating device 100 of FIG. 1 received in the case 600. The case 600 shown in FIG. 8 is substantially similar to the case 500 shown in FIG. 7, and like reference numerals are used to describe like features. The case 600 is a portable charging case having a case housing 602 that is shaped and sized to be held in a hand of a user and to fit into a pocket of a user's clothing.

[0228] The case housing 602 defines a case cavity 604, and comprises a lid 605, both of which are identical to the case cavity 504 and lid 505 described above in relation to the embodiment of FIG. 7. A case power supply 606, in the form of a lithium-ion battery with a capacity of about 2900 milliampere-hours (mAh), is housed within the case housing 602. An electrical connector (not shown) is also arranged at the distal end of the case cavity 604 for receiving the aerosol-generating device, as described above in relation to the embodiment of FIG. 7. A case controller 610 is housed within the case housing 602, and is arranged and configured substantially as described above in relation to the embodiment of FIG. 7.

[0229] In accordance with the present invention, the case 600 comprises a residue detector. In this embodiment, the residue detector is an optical residue detector comprising a light source 620, in the form of an LED configured to emit substantially white light, a light sensor 622, in the form of a photodiode, and two light guides 624, 626.

[0230] In this embodiment, the device housing 102 of the aerosol-generating device comprises a window 107 at the base of the device cavity 104. The window 107 enables light to travel through the device housing 102, into and out of the device cavity 104. In this embodiment, the window 107 is comprised of a transparent, high temperature plastics material. However, in other embodiments, the window may be a slot or space in the device housing 104 to enable light to travel into and out of the device cavity 104.

[0231] The light guides 624, 627 of the optical residue detector of the case 600 are arranged to direct light into and out of the window 107 in the device housing 102 when the aerosol-generating device 100 is received in the case cavity 604. A first light guide 624 is arranged to direct light from the LED 620 into the device cavity 104, through the window 107 in the device housing 102. A second light guide 626 is arranged to direct light from the device cavity 104 to the photodiode 622, through the window 107 in the device housing 102.

[0232] The case controller 610 is configured to determine an indication of the amount of aerosol-forming substrate residue in the device cavity 104 and on the heater 106 based on readings from the photodiode 622.

[0233] FIG. 9 shows a residue detector device 700 according to another embodiment of the present invention. The residue detector device 700 comprises a residue detector body 702 defining a substantially hemispherical detector cavity 704. The detector cavity 704 is shaped and sized to receive a proximal portion of an aerosol-generating device, such as the aerosol-generating device 100 of the embodiment of FIG. 1, as shown in FIG. 9.

[0234] In accordance with the present invention, the residue detector device 700 comprises a residue detector. In this embodiment, the residue detector is an optical residue detector comprising a light source 706, in the form of an LED configured to emit substantially white light, and a light sensor 708, in the form of a photodiode.

[0235] The LED 706 is positioned towards an edge of the hemispherical detector cavity 704, and arranged to direct light towards the opposite side of the detector cavity 704. The surface of the detector cavity 704 is provided with a reflective coating for reflecting the light from the LED 708. The hemispherical shape of the detector cavity 704 results in light incident on the surface of the cavity 704 being reflected in all directions, such that light from the LED 706 may fall on most surfaces of a device cavity 104 and heater 106 of the aerosol-generating device 100 when the proximal end of the aerosol-generating device 100 is received in the detector cavity 704.

[0236] The photodiode 708 is arranged at one end of a channel 710, which extends centrally through the detector housing 702 from the surface of the detector cavity 704 to the photodiode 708. The channel 710 is configured to enable light to travel from the detector cavity 704 to the photodiode 708. In this embodiment, the channel is an empty channel, but in some embodiments the channel may comprise a light guide, such as an optical fibre.

[0237] The residue detector device 700 further comprises a power supply 712 and a controller 714 housed in the detector housing 702. The residue detector device 700 also comprises a switch 716 and visual indicator 716 in the form of an LED on an external surface of the detector housing 702.

[0238] The detector controller 714 is configured to control a supply of power from the detector power supply 712 to the LED 706 and photodiode 708 of the optical residue detector, and to the LED of the visual indicator 716. The detector controller 714 is further configured to illuminate the LED 706 of the optical residue detector and take readings from the photodiode 708 when a user presses the switch 716. The controller is configured to determine an indication of the amount of aerosol-forming substrate residue in the device cavity 104 and on the heater 106 of the aerosol-generating device 100 received in the detector cavity 704 based on signals from the photodiode 708. When the determined indication of the amount of residue is above a predetermined threshold stored in a memory of the detector controller 714, the detector controller 714 is configured to illuminate the visual indicator LED 716 to alert a user that the amount of aerosol-forming substrate residue in the device cavity 104 and on the heater 106 is above an acceptable level and the aerosol-generating device 100 requires cleaning.

[0239] It will be appreciated that in other embodiments the residue detector device may comprise other residue detectors. For example, the residue detector device may comprise one or more of a VOC detector and a carbon dioxide detector. In other embodiments, the residue detector device may also be a part of a cleaning system. The cleaning system may comprise the residue detector device and a cleaning tool, such as a brush. The cleaning tool and the residue detector device may be removably securable together. A coupler may be provided to removably secure together the cleaning tool and the residue detector device.