Patent Description:
Combustion of organic material such as tobacco is known to produce tar and other potentially harmful by-products. There have been proposed various smoking substitute systems (or "substitute smoking systems") in order to avoid the smoking of tobacco.

Smoking substitute systems include electronic systems that permit a user to simulate the act of smoking by producing an aerosol (also referred to as a "vapour") that is drawn into the lungs through the mouth (inhaled) and then exhaled. The inhaled aerosol typically bears nicotine and/or flavourings without, or with fewer of, the odour and health risks associated with traditional smoking.

In general, smoking substitute systems are intended to provide a substitute for the rituals of smoking, whilst providing the user with a similar experience and satisfaction to those experienced with traditional smoking and with combustible tobacco products. Some smoking substitute systems use smoking substitute articles (also referred to as a "consumables") that are designed to resemble a traditional cigarette and are cylindrical in form with a mouthpiece at one end.

The popularity and use of smoking substitute systems has grown rapidly in the past few years. Although originally marketed as an aid to assist habitual smokers wishing to quit tobacco smoking, consumers are increasingly viewing smoking substitute systems as desirable lifestyle accessories.

There are a number of different categories of smoking substitute systems, each utilising a different smoking substitute approach.

One approach for a smoking substitute system is the so-called Heated Tobacco ("HT") approach in which tobacco (rather than an "e-liquid") is heated or warmed to release vapour. HT is also known as "heat not burn" ("HNB"). The tobacco may be leaf tobacco or reconstituted tobacco. The vapour may contain nicotine and/or flavourings. In the HT approach the intention is that the tobacco is heated but not burned, i.e. the tobacco does not undergo combustion.

A typical HT smoking substitute system may include a device and a consumable. The consumable may include the tobacco material. The device and consumable may be configured to be physically coupled together. In use, heat may be imparted to the tobacco material by a heating element of the device, wherein airflow through the tobacco material causes components in the tobacco material to be released as vapour. A vapour may also be formed from a carrier in the tobacco material (this carrier may for example include propylene glycol and/or vegetable glycerine) and additionally volatile compounds released from the tobacco. The released vapour may be entrained in the airflow drawn through the tobacco.

There may be a need for improved design of smoking substitute systems, in particular HT smoking substitute systems, to enhance the user experience and improve the function of the HT smoking substitute system. <CIT> proposes an apparatus for heating smokable material. <CIT> proposes an electronic vaping device, battery section and charger. <CIT> proposes an over current and short circuit protection device for an electronic cigarette. <CIT> proposes a method, system and device for controlling a heating element.

At its most general, the present invention relates to a heated tobacco device, including a multilayer printed circuit board (PCB).

According to a first aspect, there is provided a heated tobacco device as set out in claim <NUM>.

The provision of separate power and ground layers may provide noise insulation, signal integrity and an efficient distribution of power.

The power and ground layers are sandwiched between the top and bottom layers. Each of the layers (which may be formed of e.g. copper sheet) may be separated by an insulative layer to provide electrical insulation between the layers. One or more of the layers may be separated by a dialetric layer. One or more of the layers may be separated by a prepreg layer. A plurality of components (e.g. resistors, transistors, microprocessors, etc.) may be mounted to the top and/or bottom layers. The top and bottom layers may each comprise a plurality of traces (or paths) electrically connecting the components mounted thereto. One or both of the top and bottom layers may be electrically connected to the power and ground layers.

The device may comprise a voltage regulator to regulate the voltage supplied by the power source to a regulated voltage value at an output of the voltage regulator. The power layer may be connected to the output of the voltage regulator. This may ensure a consistent voltage is supplied to the power layer.

The device may comprise a first heater control transistor configured to control (e.g. by switching between an "on" and an "off" state) the supply of power to the heater from the power source. The device may further comprise a second heater control transistor connected in series with the first transistor. The first and/or second transistor may be a metal-oxide-semiconductor field-effect transistor (MOSFET). The second transistor may be configured to control the supply of power to the heater from the power source. The heater may be controlled using pulse width modulation. Thus, the transistors may be turned on an off according to a duty cycle. The duty cycle may be altered to alter the temperature of the heater.

The first and second transistors may both be on the return path from the heater to the power source. Alternatively, the first transistor may be on the forward path from the power source to the heater and the second transistor may be on the return path. Alternatively, both transistors may be on the forward path. The use of two transistors may increase the reliability of the device. For example, if one transistor becomes "stuck" in an on position, the other transistor may ensure that an instruction to stop the supply of power (e.g. from a controller) is still acted upon.

The device may comprise a controller connected to a first drive input of the first transistor. The controller may be connected to a second drive input of the second transistor. Thus the controller may be configured to control (e.g. control switching of) the first and second transistors.

The first drive input and the second drive input may be connected to the same output of the controller. Thus, the first and second transistors may be controlled in a simultaneous manner.

The first drive input and the second drive input may be connected to different outputs of the controller. In this respect, the first and second transistors may be controlled in a different manner to one another. In some cases the two outputs of the controller may provide the same signal or instruction. In such cases, the use of the two separate outputs may provide redundancy in the system.

The heater may comprise a heating track. The PCB may comprise a heater analog-to-digital converter (HADC) connected to the heater. The controller may be configured to identify a short circuit in the heating track of the heater using the input to the HADC. The controller may be configured to detect changes in the resistance (or impedance) of the heating track. The controller may be configured to determine whether the impedance or resistance of heater falls below a threshold value. The controller may be configured to control the heater in response to the identification of a short circuit in the heating track.

The heater may comprise a temperature sensing track for sensing a temperature of the heater, the PCB comprising a temperature sensing analog-to-digital converter (TSADC) connected to the temperature sensing track. The controller may be configured to determine the temperature of the temperature sensing track using the input to the TSADC. The controller may be configured to determine the temperature of the sensing track using the output from the TSADC.

The controller may be configured to compare the determined temperature with a threshold temperature and control the heater in response to the comparison. The controller may be configured to determine if the impedance of the temperature sensing track is outside a predetermined operating range, and to prevent power supply to the heater if the impedance is outside the predetermined operating range.

The device may comprise an elongate body. An end of the elongate body may be configured for engagement with an aerosol-forming article (e.g. a heated tobacco (HT) consumable). The device may comprise a cavity that is configured for receipt of at least a portion of the consumable (i.e. for engagement with the consumable). The aerosol-forming article may be of the type that comprises an aerosol former (e.g. carried by an aerosol-forming substrate).

The heater may comprise a heating element, which may be in the form of a rod that extends from the body of the device. The heating element may extend from the end of the body that is configured for engagement with the aerosol-forming article.

The heater (and thus the heating element) may be rigidly mounted to the body. The heating element may be elongate so as to define a longitudinal axis and may, for example, have a transverse profile (i.e. transverse to a longitudinal axis of the heating element) that is substantially circular (i.e. the heating element may be generally cylindrical). Alternatively, the heating element may have a transverse profile that is rectangular (i.e. the heater may be a "blade heater"). The heating element may alternatively be in the shape of a tube (i.e. the heater may be a "tube heater"). The heating element may take other forms (e.g. the heating element may have an elliptical transverse profile). The shape and/or size (e.g. diameter) of the transverse profile of the heating element may be generally consistent for the entire length (or substantially the entire length) of the heating element.

The heating element may be between <NUM> and <NUM> long, e.g. between <NUM> and <NUM> long, e.g. around <NUM> long. The heating element may have a diameter of between <NUM> and <NUM>, e.g. a diameter between <NUM> and <NUM>, e.g. a diameter of around <NUM>.

The heating element may be formed of ceramic. The heating element may comprise a core (e.g. a ceramic core) comprising Al2O3. The core of the heating element may have a diameter of <NUM> to <NUM>, e.g. between <NUM> and <NUM>. The heating element may comprise an outer layer (e.g. an outer ceramic layer) comprising Al2O3. The thickness of the outer layer may be between <NUM> and <NUM>, e.g. between <NUM> and <NUM>, e.g. around <NUM>. The heating element may comprise a heating track, which may extend longitudinally along the heating element. The heating track may be sandwiched between the outer layer and the core of the heating element. The heating track is an electrically conductive resistive heating track comprising a pair of heater electrodes (not shown) connected to the power supply of the heater. The heating track may comprise tungsten and/or rhenium. The heating track may have a thickness of around <NUM>.

The heating element may be located in the cavity (of the device), and may extend (e.g. along a longitudinal axis) from an internal base of the cavity towards an opening of the cavity. The length of the heating element (i.e. along the longitudinal axis of the heater) may be less than the depth of the cavity. Hence, the heating element may extend for only a portion of the length of the cavity. That is, the heating element may not extend through (or beyond) the opening of the cavity.

The heating element may be configured for insertion into an aerosol-forming article (e.g. a HT consumable) when an aerosol-forming article is received in the cavity. In that respect, a distal end (i.e. distal from a base of the heating element where it is mounted to the device) of the heating element may comprise a tapered portion, which may facilitate insertion of the heating element into the aerosol-forming article. The heating element may fully penetrate an aerosol-forming article when the aerosol-forming article is received in the cavity. That is, the entire length, or substantially the entire length, of the heating element may be received in the aerosol-forming article.

The heating element may have a length that is less than, or substantially the same as, an axial length of an aerosol-forming substrate forming part of an aerosol-forming article (e.g. a HT consumable). Thus, when such an aerosol-forming article is engaged with the device, the heating element may only penetrate the aerosol-forming substrate, rather than other components of the aerosol-forming article. The heating element may penetrate the aerosol-forming substrate for substantially the entire axial length of the aerosol forming-substrate of the aerosol-forming article. Thus, heat may be transferred from (e.g. an outer circumferential surface of) the heating element to the surrounding aerosol-forming substrate, when penetrated by the heating element. That is, heat may be transferred radially outwardly (in the case of a cylindrical heating element) or e.g. radially inwardly (in the case of a tube heater).

Where the heater is a tube heater, the heating element of the tube heater may surround at least a portion of the cavity. When the portion of the aerosol-forming article is received in the cavity, the heating element may surround a portion of the aerosol-forming article (i.e. so as to heat that portion of the aerosol-forming article). In particular, the heating element may surround an aerosol forming substrate of the aerosol-forming article. That is, when an aerosol-forming article is engaged with the device, the aerosol forming substrate of the aerosol-forming article may be located adjacent an inner surface of the (tubular) heating element. When the heating element is activated, heat may be transferred radially inwardly from the inner surface of the heating element to heat the aerosol forming substrate.

The cavity may comprise a (e.g. circumferential) wall (or walls) and the (tubular) heating element may extend around at least a portion of the wall(s). In this way, the wall may be located between the inner surface of the heating element and an outer surface of the aerosol-forming article. The wall (or walls) of the cavity may be formed from a thermally conductive material (e.g. a metal) to allow heat conduction from the heating element to the aerosol-forming article. Thus, heat may be conducted from the heating element, through the cavity wall (or walls), to the aerosol-forming substrate of an aerosol-forming article received in the cavity.

The heater also comprises an electrically conductive temperature measurement track and corresponding pair of temperature measurement electrodes connected to a controller of the device. In one aspect, the temperature measurement track is formed with tungsten.

In some embodiments the device may comprise a cap disposed at the end of the body that is configured for engagement with an aerosol-forming article. Where the device comprises a heater having a heating element, the cap may at least partially enclose the heating element. The cap may be moveable between an open position in which access is provided to the heating element, and a closed position in which the cap at least partially encloses the heating element. The cap may be slideably engaged with the body of the device, and may be slideable between the open and closed positions.

The cap may define at least a portion of the cavity of the device. That is, the cavity may be fully defined by the cap, or each of the cap and body may define a portion of the cavity. The cap may comprise an opening to the cavity. The opening may be configured for receipt of at least a portion of an aerosol-forming article. That is, an aerosol-forming article may be inserted through the opening and into the cavity (so as to be engaged with the device).

The cap may be configured such that when an aerosol-forming article is engaged with the device (e.g. received in the cavity), only a portion of the aerosol-forming article is received in the cavity. That is, a portion of the aerosol-forming article (not received in the cavity) may protrude from (i.e. extend beyond) the opening. This (protruding) portion of the aerosol-forming article may be a terminal (e.g. mouth) end of the aerosol-forming article, which may be received in a user's mouth for the purpose of inhaling aerosol formed by the device.

The device comprises a power source. The power source may be electrically connectable to the heater. In that respect, altering (e.g. toggling) the electrical connection of the power source to the heater may affect a state of the heater. For example, toggling the electrical connection of the power source to the heater may toggle the heater between an on state and an off state. The power source may be a power store. For example, the power source may be a battery or rechargeable battery (e.g. a lithium ion battery).

The device may comprise an input connection (e.g. a USB port, Micro USB port, USB-C port, etc.). The input connection may be configured for connection to an external source of electrical power, such as a mains electrical supply outlet. The input connection may, in some cases, be used as a substitute for an internal power source (e.g. battery or rechargeable battery). That is, the input connection may be electrically connectable to the heater (for providing power to the heater). Hence, in some forms, the input connection may form at least part of the power source of the device. The input connection may be connected to the PCB.

Where the power source comprises a rechargeable power source (such as a rechargeable battery), the input connection may be used to charge and recharge the power source.

The device may comprise a user interface (UI). In some embodiments the UI may include input means to receive operative commands from the user. The UI may be connected to the PCB. The input means of the UI may allow the user to control at least one aspect of the operation of the device. In some embodiments the input means may comprise a power button to switch the device between an on state and an off state.

In some embodiments the UI may additionally or alternatively comprise output means to convey information to the user. In some embodiments the output means may comprise a light to indicate a condition of the device (and/or the aerosol-forming article) to the user. The condition of the device (and/or aerosol-forming article) indicated to the user may comprise a condition indicative of the operation of the heater. For example, the condition may comprise whether the heater is in an off state or an on state. In some embodiments, the UI unit may comprise at least one of a button, a display, a touchscreen, a switch, a light, and the like. For example, the output means may comprise one or more (e.g. two, three, four, etc.) light-emitting diodes ("LEDs") that may be located on the body of the device.

The device may further comprise a puff sensor (e.g. airflow sensor), which form part of the input means of the UI. The puff sensor may be operatively connected to the PCB. The puff sensor may be configured to detect a user drawing on an end (i.e. a terminal (mouth) end) of the aerosol-forming article. The puff sensor may, for example, be a pressure sensor or a microphone. The puff sensor may be configured to produce a signal indicative of a puff state. The signal may be indicative of the user drawing (an aerosol from the aerosol-forming article) such that it is e.g. in the form of a binary signal. Alternatively or additionally, the signal may be indicative of a characteristic of the draw (e.g. a flow rate of the draw, length of time of the draw, etc).

The device may comprise a controller, or may be connectable to a controller that may be configured to control at least one function of the device. The controller may comprise a microcontroller that may e.g. be mounted on the PCB. The controller may comprise a plurality of microcontrollers. The controller may also comprise a memory, e.g. non-volatile memory. The memory may include instructions, which, when implemented, may cause the controller to perform certain tasks or steps of a method. Where the device comprises an input connection, the controller may be connected to the input connection.

The device may further comprise a voltage regulator to regulate the output voltage supplied by the power source to form a regulated voltage. The regulated voltage may subsequently be applied to the heater.

In some embodiments, where the device comprises a UI, the controller may be operatively connected to one or more components of the UI. The controller may be configured to receive command signals from an input means of the UI. The controller may be configured to control the heater in response to the command signals. For example, the controller may be configured to receive "on" and "off" command signals from the UI and, in response, may control the heater so as to be in a corresponding on or off state.

The controller may be configured to send output signals to a component of the UI. The UI may be configured to convey information to a user, via an output means, in response to such output signals (received from the controller). For example, where the device comprises one or more LEDs, the LEDs may be operatively connected to the controller. Hence, the controller may be configured to control the illumination of the LEDs (e.g. in response to an output signal). For example, the controller may be configured to control the illumination of the LEDs according to (e.g. an on or off) state of the heater. Where the device comprises a sensor (e.g. a puff/airflow sensor), the controller may be operatively connected to the sensor. The controller may be configured to receive a signal from the sensor (e.g. indicative of a condition of the device and/or engaged aerosol-forming article). The controller may be configured to control the heater, or an aspect of the output means, based on the signal from the sensor.

The device may comprise a wireless interface configured to communicate wirelessly (e.g. via Bluetooth (e.g. a Bluetooth low-energy connection) or Wi-Fi) with an external device. Similarly, the input connection may be configured for wired connection to an external device so as to provide communication between the device and the external device.

The external device may be a mobile device. For example, the external device may be a smart phone, tablet, smart watch, or smart car. An application (e.g. app) may be installed on the external device (e.g. mobile device). The application may facilitate communication between the device and the external device via the wired or wireless connection.

The wireless or wired interface may be configured to transfer signals between the external device and the controller of the device. In this respect, the controller may control an aspect of the device in response to a signal received from an external device. Alternatively or additionally, an external device may respond to a signal received from the device (e.g. from the controller of the device).

In a second aspect, there is provided a system (e.g. a smoking substitute system) comprising a device according to the first aspect and an aerosol-forming article. The aerosol-forming article may comprise an aerosol-forming substrate at an upstream end of the aerosol-forming article. The article may be in the form of a smoking substitute article, e.g. heated tobacco (HT) consumable (also known as a heat-not-burn (HNB) consumable).

As used herein, the terms "upstream" and "downstream" are intended to refer to the flow direction of the vapour/aerosol i.e. with the downstream end of the article/consumable being the mouth end or outlet where the aerosol exits the consumable for inhalation by the user. The upstream end of the article/consumable is the opposing end to the downstream end.

The aerosol-forming substrate is capable of being heated to release at least one volatile compound that can form an aerosol. The aerosol-forming substrate may be located at the upstream end of the article/consumable.

In order to generate an aerosol, the aerosol-forming substrate comprises at least one volatile compound that is intended to be vaporised/aerosolised and that may provide the user with a recreational and/or medicinal effect when inhaled. Suitable chemical and/or physiologically active volatile compounds include the group consisting of: nicotine, cocaine, caffeine, opiates and opoids, cathine and cathinone, kavalactones, mysticin, beta-carboline alkaloids, salvinorin A together with any combinations, functional equivalents to, and/or synthetic alternatives of the foregoing.

The aerosol-forming substrate may comprise plant material. The plant material may comprise least one plant material selected from the list including Amaranthus dubius, Arctostaphylos uva-ursi (Bearberry), Argemone mexicana, Amica, Artemisia vulgaris, Yellow Tees, Galea zacatechichi, Canavalia maritima (Baybean), Cecropia mexicana (Guamura), Cestrum noctumum, Cynoglossum virginianum (wild comfrey), Cytisus scoparius, Damiana, Entada rheedii, Eschscholzia califomica (California Poppy), Fittonia albivenis, Hippobroma longiflora, Humulus japonica (Japanese Hops), Humulus lupulus (Hops), Lactuca virosa (Lettuce Opium), Laggera alata, Leonotis leonurus, Leonurus cardiaca (Motherwort), Leonurus sibiricus (Honeyweed), Lobelia cardinalis, Lobelia inflata (Indian-tobacco), Lobelia siphilitica, Nepeta cataria (Catnip), Nicotiana species (Tobacco), Nymphaea alba (White Lily), Nymphaea caerulea (Blue Lily), Opium poppy, Passiflora incamata (Passionflower), Pedicularis densiflora (Indian Warrior), Pedicularis groenlandica (Elephant's Head), Salvia divinorum, Salvia dorrii (Tobacco Sage), Salvia species (Sage), Scutellaria galericulata, Scutellaria lateriflora, Scutellaria nana, Scutellaria species (Skullcap), Sida acuta (Wireweed), Sida rhombifolia, Silene capensis, Syzygium aromaticum (Clove), Tagetes lucida (Mexican Tarragon), Tarchonanthus camphoratus, Tumera diffusa (Damiana), Verbascum (Mullein), Zamia latifolia (Maconha Brava) together with any combinations, functional equivalents to, and/or synthetic alternatives of the foregoing.

The plant material may be tobacco. Any type of tobacco may be used. This includes, but is not limited to, flue-cured tobacco, burley tobacco, Maryland Tobacco, dark-air cured tobacco, oriental tobacco, dark-fired tobacco, perique tobacco and rustica tobacco. This also includes blends of the above mentioned tobaccos.

The tobacco may comprise one or more of leaf tobacco, stem tobacco, tobacco powder, tobacco dust, tobacco derivatives, expanded tobacco, homogenised tobacco, shredded tobacco, extruded tobacco, cut rag tobacco and/or reconstituted tobacco (e.g. slurry recon or paper recon).

The aerosol-forming substrate may comprise a gathered sheet of homogenised (e.g. paper/slurry recon) tobacco or gathered shreds/strips formed from such a sheet.

The aerosol-forming substrate may comprise one or more additives selected from humectants, flavourants, fillers, aqueous/non-aqueous solvents and binders.

The flavourant may be provided in solid or liquid form. It may include menthol, liquorice, chocolate, fruit flavour (including e.g. citrus, cherry etc.), vanilla, spice (e.g. ginger, cinnamon) and tobacco flavour. The flavourant may be evenly dispersed throughout the aerosol-forming substrate or may be provided in isolated locations and/or varying concentrations throughout the aerosol-forming substrate.

The aerosol-forming substrate may be formed in a substantially cylindrical shape such that the article/consumable resembles a conventional cigarette. It may have a diameter of between <NUM> and <NUM> e.g. between <NUM> and <NUM> or <NUM> and <NUM> e.g. around <NUM>. It may have an axial length of between <NUM> and <NUM> e.g. between <NUM> and <NUM> such as around <NUM> or <NUM>.

The article/consumable may comprise at least one filter element. There may be a terminal filter element at the downstream/mouth end of the article/consumable.

The or at least one of the filter element(s) (e.g. the terminal filter element) may be comprised of cellulose acetate or polypropylene tow. The at least one filter element (e.g. the terminal filter element) may be comprised of activated charcoal. The at least one filter element (e.g. the terminal element) may be comprised of paper. The or each filter element may be at least partly (e.g. entirely) circumscribed with a plug wrap e.g. a paper plug wrap.

The terminal filter element (at the downstream end of the article/consumable) may be joined to the upstream elements forming the article/consumable by a circumscribing tipping layer e.g. a tipping paper layer. The tipping paper may have an axial length longer than the axial length of the terminal filter element such that the tipping paper completely circumscribes the terminal filter element plus the wrapping layer surrounding any adjacent upstream element.

In some embodiments, the article/consumable may comprise an aerosol-cooling element which is adapted to cool the aerosol generated from the aerosol-forming substrate (by heat exchange) before being inhaled by the user.

The article/consumable may comprise a spacer element that defines a space or cavity between the aerosol-forming substrate and the downstream end of the consumable. The spacer element may comprise a cardboard tube. The spacer element may be circumscribed by the (paper) wrapping layer.

According to a third aspect of the present invention, there is provided a method of using the system according to the second aspect, the method comprising inserting the aerosol-forming article into the device; and heating the article using the heater of the device.

In some embodiments the method may comprise inserting the article into a cavity within a body of the device and penetrating the article with the heating element of the device upon insertion of the article.

<FIG> is a schematic providing a general overview of a smoking substitute system <NUM>. The system <NUM> includes a substitute smoking device <NUM> and an aerosol-forming article in the form of a consumable <NUM>, which comprises an aerosol former <NUM>. The system is configured to vaporise the aerosol former by heating the aerosol former <NUM> (so as to form a vapour/aerosol for inhalation by a user).

In the illustrated system, the heater <NUM> forms part of the device <NUM> and is configured to heat the aerosol former <NUM>. Heat from the heater <NUM> vaporises the aerosol former <NUM> to produce a vapour. The vapour subsequently condenses to form an aerosol, which is ultimately inhaled by the user. In one aspect, the heater <NUM> comprises a heating track (not shown) and a temperature sensing track (not shown) for measuring the temperature of the heater <NUM>.

The system <NUM> further comprises a power source <NUM> that forms part of the device <NUM>. In other embodiments the power source <NUM> may be external to (but connectable to) the device <NUM>. The power source <NUM> is electrically connectable to the heater <NUM> such that the power source <NUM> is able to supply power to the heater <NUM> (i.e. for the purpose of heating the aerosol former <NUM>). Thus, control of the electrical connection of the power source <NUM> to the heater <NUM> provides control of the state of the heater <NUM>. The power source <NUM> may be a power store, for example a battery or rechargeable battery (e.g. a lithium ion battery).

The system <NUM> further comprises an I/O module comprising a connector <NUM> (e.g. in the form of a USB port, Micro USB port, USB-C port, etc.). The connector <NUM> is configured for connection to an external source of electrical power, e.g. a mains electrical supply outlet. The connector <NUM> may be used in substitution for the power source <NUM>. That is the connector <NUM> may be electrically connectable to the heater <NUM> so as to supply electricity to the heater <NUM>. In such embodiments, the device may not include a power source, and the power source of the system may instead comprise the connector <NUM> and an external source of electrical power (to which the connector <NUM> provides electrical connection).

In some embodiments, the connector <NUM> may be used to charge and recharge the power source <NUM> where the power source <NUM> includes a rechargeable battery.

The system <NUM> also comprises a user interface (UI) <NUM>. Although not shown, the UI <NUM> may include input means to receive commands from a user. The input means of the UI <NUM> allows the user to control at least one aspect of the operation of the system <NUM>. The input means may, for example, be in the form of a button, touchscreen, switch, microphone, etc..

The UI <NUM> also comprises output means to convey information to the user. The output means may, for example, comprise lights (e.g. LEDs), a display screen, speaker, vibration generator, etc..

The system <NUM> further comprises a controller <NUM> that is configured to control at least one function of the device <NUM>. In the illustrated embodiment, the controller <NUM> is a component of the device <NUM>, but in other embodiments may be separate from (but connectable to) the device <NUM>. The controller <NUM> is configured to control the operation of the heater <NUM> and, for example, may be configured to control the voltage applied from the power source <NUM> to the heater <NUM>. The controller <NUM> may be configured to toggle the supply of power to the heater <NUM> between an on state, in which the full output voltage of the power source <NUM> is applied to the heater <NUM>, and an off state, in which the no voltage is applied to the heater <NUM>.

The system <NUM> further comprises a printed circuit board (PCB) <NUM> with a power layer, a ground layer and top and bottom layers. The power and ground layers are sandwiched between the top and bottom layers.

Although not shown, the system <NUM> may also comprise a voltage regulator to regulate the output voltage from the power source <NUM> to form a regulated voltage. The regulated voltage may then be applied to the heater <NUM>. The power layer of the PCB <NUM> is connected to the output of the voltage regulator.

In addition to being connected to the heater <NUM>, the controller <NUM> is operatively connected to the UI <NUM>. Thus, the controller <NUM> may receive an input signal from the input means of the UI <NUM>. Similarly, the controller <NUM> may transmit output signals to the UI <NUM>. In response, the output means of the UI <NUM> may convey information, based on the output signals, to a user.

<FIG> illustrate a heated-tobacco (HT) smoking substitute system <NUM>. The system <NUM> is an example of the systems <NUM> described in relation to <FIG>. System <NUM> includes an HT device <NUM> and an HT consumable <NUM>. The description of <FIG> above is applicable to the system <NUM> of <FIG>, and will thus not be repeated.

The device <NUM> and the consumable <NUM> are configured such that the consumable <NUM> can be engaged with the device <NUM>. <FIG> shows the device <NUM> and the consumable <NUM> in an engaged state, whilst <FIG> shows the device <NUM> and the consumable <NUM> in a disengaged state.

The device <NUM> comprises a body <NUM> and cap <NUM>. In use the cap <NUM> is engaged at an end of the body <NUM>. Although not apparent from the figures, the cap <NUM> is moveable relative to the body <NUM>. In particular, the cap <NUM> is slideable and can slide along a longitudinal axis of the body <NUM>. The device <NUM> comprises an output means (forming part of the UI of the device <NUM>) in the form of a plurality of light-emitting diodes (LEDs) <NUM> arranged linearly along the longitudinal axis of the device <NUM> and on an outer surface of the body <NUM> of the device <NUM>. A button <NUM> is also arranged on an outer surface of the body <NUM> of the device <NUM> and is axially spaced (i.e. along the longitudinal axis) from the plurality of LEDs <NUM>.

<FIG> show a detailed section view of the consumable of <NUM> of the system <NUM>. The consumable <NUM> generally resembles a cigarette. In that respect, the consumable <NUM> has a generally cylindrical form with a diameter of <NUM> and an axial length of <NUM>. The consumable <NUM> comprises an aerosol forming substrate <NUM>, a terminal filter element <NUM>, an upstream filter element <NUM> and a spacer element <NUM>. In other embodiments, the consumable may further comprise a cooling element. A cooling element may exchange heat with vapour that is formed by the aerosol-forming substrate <NUM> in order to cool the vapour so as to facilitate condensation of the vapour.

The aerosol-forming substrate <NUM> is substantially cylindrical and is located at an upstream end <NUM> of the consumable <NUM>, and comprises the aerosol former of the system <NUM>. In that respect, the aerosol forming substrate <NUM> is configured to be heated by the device <NUM> to release a vapour. The released vapour is subsequently entrained in an airflow flowing through the aerosol-forming substrate <NUM>. The airflow is produced by the action of the user drawing on a downstream <NUM> (i.e. terminal or mouth end) of the consumable <NUM>.

In the present embodiment, the aerosol forming substrate <NUM> comprises tobacco material that may, for example, include any suitable parts of the tobacco plant (e.g. leaves, stems, roots, bark, seeds and flowers). The tobacco may comprise one or more of leaf tobacco, stem tobacco, tobacco powder, tobacco dust, tobacco derivatives, expanded tobacco, homogenised tobacco, shredded tobacco, extruded tobacco, cut rag tobacco and/or reconstituted tobacco (e.g. slurry recon or paper recon). For example, the aerosol-forming substrate <NUM> may comprise a gathered sheet of homogenised (e.g. paper/slurry recon) tobacco or gathered shreds/strips formed from such a sheet.

In order to generate an aerosol, the aerosol forming substrate <NUM> comprises at least one volatile compound that is intended to be vaporised/aerosolised and that may provide the user with a recreational and/or medicinal effect when inhaled. The aerosol-forming substrate <NUM> may further comprise one or more additives. For example, such additives may be in the form of humectants (e.g. propylene glycol and/or vegetable glycerine), flavourants, fillers, aqueous/non-aqueous solvents and/or binders.

The terminal filter element <NUM> is also substantially cylindrical, and is located downstream of the aerosol forming substrate <NUM> at the downstream end <NUM> of the consumable <NUM>. The terminal filter element <NUM> is in the form of a hollow bore filter element having a bore <NUM> (e.g. for airflow) formed therethrough. The diameter of the bore <NUM> is <NUM>. The terminal filter element <NUM> is formed of a porous (e.g. monoacetate) filter material. As set forth above, the downstream end <NUM> of the consumable <NUM> (i.e. where the terminal filter <NUM> is located) forms a mouthpiece portion of the consumable <NUM> upon which the user draws. Airflow is drawn from the upstream end <NUM>, thorough the components of the consumable <NUM>, and out of the downstream end <NUM>. The airflow is driven by the user drawing on the downstream end <NUM> (i.e. the mouthpiece portion) of the consumable <NUM>.

The upstream filter element <NUM> is located axially adjacent to the aerosol-forming substrate <NUM>, between the aerosol-forming substrate <NUM> and the terminal filter element <NUM>. Like the terminal filter <NUM>, the upstream filter element <NUM> is in the form of a hollow bore filter element, such that it has a bore <NUM> extending axially therethrough. In this way, the upstream filter <NUM> may act as an airflow restrictor. The upstream filter element <NUM> is formed of a porous (e.g. monoacetate) filter material. The bore <NUM> of the upstream filter element <NUM> has a larger diameter (<NUM>) than the terminal filter element <NUM>.

The spacer <NUM> is in the form of a cardboard tube, which defines a cavity or chamber between the upstream filter element <NUM> and the terminal filter element <NUM>. The spacer <NUM> acts to allow both cooling and mixing of the vapour/aerosol from the aerosol-forming substrate <NUM>. The spacer has an external diameter of <NUM> and an axial length of <NUM>.

Although not apparent from the figure, the aerosol-forming substrate <NUM>, upstream filter <NUM> and spacer <NUM> are circumscribed by a paper wrapping layer. The terminal filter <NUM> is circumscribed by a tipping layer that also circumscribes a portion of the paper wrapping layer (so as to connect the terminal filter <NUM> to the remaining components of the consumable <NUM>). The upstream filter <NUM> and terminal filter <NUM> are circumscribed by further wrapping layers in the form of plug wraps.

Returning now to the device <NUM>, <FIG> illustrates a detailed view of the end of the device <NUM> that is configured to engage with the consumable <NUM>. The cap <NUM> of the device <NUM> includes an opening <NUM> to an internal cavity <NUM> (more apparent from <FIG>) defined by the cap <NUM>. The opening <NUM> and the cavity <NUM> are formed so as to receive at least a portion of the consumable <NUM>. During engagement of the consumable <NUM> with the device <NUM>, a portion of the consumable <NUM> is received through the opening <NUM> and into the cavity <NUM>. After engagement (see <FIG>), the downstream end <NUM> of the consumable <NUM> protrudes from the opening <NUM> and thus protrudes also from the device <NUM>. The opening <NUM> includes laterally disposed notches <NUM>. When a consumable <NUM> is received in the opening <NUM>, these notches <NUM> remain open and could, for example, be used for retaining a cover to cover the end of the device <NUM>.

<FIG> shows a cross section through a central longitudinal plane through the device <NUM>. The device <NUM> is shown with the consumable <NUM> engaged therewith.

The device <NUM> comprises a heater <NUM> comprising heating element <NUM>. The heater <NUM> forms part of the body <NUM> of the device <NUM> and is rigidly mounted to the body <NUM>. In the illustrated embodiment, the heater <NUM> is a rod heater with a heating element <NUM> having a circular transverse profile. In other embodiments the heater may be in the form of a blade heater (e.g. heating element with a rectangular transverse profile) or a tube heater (e.g. heating element with a tubular form).

The heating element <NUM> of the heater <NUM> projects from an internal base of the cavity <NUM> along a longitudinal axis towards the opening <NUM>. As is apparent from the figure, the length (i.e. along the longitudinal axis) of the heating element is less than a depth of the cavity <NUM>. In this way, the heating element <NUM> does not protrude from or extend beyond the opening <NUM>.

When the consumable <NUM> is received in the cavity <NUM> (as is shown in <FIG>), the heating element <NUM> penetrates the aerosol-forming substrate <NUM> of the consumable <NUM>. In particular, the heating element <NUM> extends for nearly the entire axial length of the aerosol-forming substrate <NUM> when inserted therein. Thus, when the heater <NUM> is activated, heat is transferred radially from an outer circumferential surface the heating element <NUM> to the aerosol-forming substrate <NUM>.

The device <NUM> further comprises an electronics cavity <NUM>. A power source, in the form of a rechargeable battery <NUM> (a lithium ion battery), is located in electronics cavity <NUM>.

The device <NUM> comprises a controller <NUM> is configured to control at least one function of the device <NUM> and that is electrically connected to a PCB <NUM>. The controller is configured to control the operation of the heater <NUM>, which includes toggling the electrical connection of the rechargeable battery <NUM> to the heater <NUM>. As will be described further below this toggling of the electrical connection is done by way of transistors (also electrically connected to the PCB). For example, the controller is configured to control the heater <NUM> in response to a user depressing the button <NUM>. Depressing the button <NUM> may cause the controller to allow a voltage (from the rechargeable battery <NUM>) to be applied to the heater <NUM> (so as to cause the heating element <NUM> to be heated). The controller is also configured to control the LEDs <NUM> in response to (e.g. a detected) a condition of the device <NUM> or the consumable <NUM>. For example, the controller may control the LEDs to indicate whether the device <NUM> is in an on state or an off state (e.g. one or more of the LEDs may be illuminated by the controller when the device is in an on state).

The device <NUM> comprises a further input means (i.e. in addition to the button <NUM>) in the form of a puff sensor <NUM>. The puff sensor <NUM> is configured to detect a user drawing (i.e. inhaling) at the downstream end <NUM> of the consumable <NUM>. The puff sensor <NUM> may, for example, be in the form of a pressure sensor, flowmeter or a microphone. The puff sensor <NUM> is operatively connected to the controller in the electronics cavity <NUM>, such that a signal from the puff sensor <NUM>, indicative of a puff state (i.e. drawing or not drawing), forms an input to the controller (and can thus be responded to by the controller).

<FIG> is a schematic providing an exemplary PCB <NUM> connected to a number of components of a device. Such an arrangement may, for example, be used with the device <NUM> described above. As is apparent from the figure, the PCB <NUM> is a multilayer PCB and, in particular, includes four layers. The PCB <NUM> comprises top <NUM> and bottom <NUM> layers for electrically connecting and supporting a number of components (e.g. controllers, transistors, etc.). The PCB <NUM> further comprises a ground layer <NUM> and a power layer <NUM>. The power layer <NUM> is electrically connected to a power source <NUM> and the ground layer <NUM> is electrically connected to ground <NUM> (e.g. such as a ground terminal of the power source <NUM>).

The layers are separated by insulative layers <NUM> that may be formed of prepreg. However, although not shown, the top <NUM> and bottom <NUM> layers are electrically connected to the ground <NUM> and power <NUM> layers by way of e.g. vias (that extend transversely across the PCB <NUM>). In this way, power from the power source <NUM> is supplied to components supported by and/or connected to the top <NUM> and bottom <NUM> layers of the PCB <NUM>. As an example, the top layer <NUM> may be electrically connected to a heater <NUM> of the device and the bottom layer <NUM> may be connected to a sensor, such as a temperture sensor <NUM>.

Traces (i.e. printed circuits) on the PCB <NUM> allow the heater <NUM> and sensor <NUM> to communicate with components (such as a controller) electrically connected to the PCB <NUM>. <FIG> shows how these components may be arranged in more detail. In this figure, a power source <NUM>, heater <NUM> and temperature sensor <NUM> are connected to the PCB <NUM>. The PCB <NUM> comprises a voltage regulator <NUM>, two transistors <NUM> and a temperature sensor analog-to-digital convertor (TSADC) <NUM>.

The power source <NUM> supplies power to the heater <NUM>, via the voltage regulator <NUM> and the transistors <NUM>. The voltage regulator <NUM> ensures a consistent voltage is applied to the PCB <NUM> and the transistors <NUM> provide control of the power supply to the heater <NUM>.

The controller <NUM> is connected to both transistors <NUM> via the same output such that a single signal from the controller <NUM> controls both transistors <NUM> (i.e. between on and off conditions) simultaneously. The transistors <NUM> are arranged in series, such that if one transistor <NUM> fails, so as to be stuck in an on condition, switching the other transistor <NUM> to the off condition will prevent supply of power to the heater <NUM> (see <FIG>, which shows this arrangement in more detail).

The arrangement further comprises a temperature sensor <NUM>, in the form of a temperature sensing track that is mounted to a heating element of the heater <NUM> so as to be able to measure the temperature of the heater <NUM>. This temperature sensor <NUM> is connected to the controller <NUM> via the TSADC <NUM>, so as to supply a signal indicative of the temperature of the heater <NUM> to the controller <NUM>. In this way, the controller <NUM> can control the transistors <NUM> (and thus the heater <NUM>) in response to this signal. For example, if the sensed temperature exceeds a predetermined desired value, the controller <NUM> may control the transistors <NUM> to prevent power supply to the heater <NUM>. The controller <NUM> may continue to receive temperature signals and, once the temperature falls below the desired value, the controller <NUM> may control the transistors <NUM> to allow power supply to the heater <NUM>.

Whilst not shown, the controller <NUM> may also be configured to detect whether there is a short circuit in the heater <NUM>. This may, for example, be performed by detecting an impedance of the heater <NUM>. If the impedance falls below a threshold value, the controller <NUM> may control the transistors <NUM> to prevent supply of power to the heater <NUM>.

While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

Claim 1:
A heated tobacco device (<NUM>, <NUM>) comprising:
a power source (<NUM>, <NUM>, <NUM>);
a heater (<NUM>, <NUM>, <NUM>); and
a printed circuit board "PCB" (<NUM>, <NUM>, <NUM>) comprising a power layer (<NUM>) connected to the power source (<NUM>, <NUM>, <NUM>), a ground layer (<NUM>), a top layer (<NUM>) and a bottom layer (<NUM>), wherein the top and bottom layers (<NUM>, <NUM>) are configured to electrically connect and support one or more components, characterised in that the power and ground layers (<NUM>, <NUM>) are sandwiched between the top and bottom layers (<NUM>, <NUM>).