Electronic smoking article comprising one or more microheaters

Abstract

To provide an electronic smoking article that provides improved aerosol delivery.SOLUTION: The article comprises one or more microheaters 50. Each microheater 50 is formed of a supporting layer 510, a protective layer 540, and a patterned electrically conductive layer 520 sandwiched between the supporting layer and the protective layer. In various embodiments, the microheaters 50 provide improved control of vaporization of an aerosol precursor composition and provide reduced power requirements to achieve consistent aerosolization.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to aerosol delivery articles and their use for obtaining tobacco components or other substances in inhalable form, which articles may be made from, derived from, or otherwise incorporate tobacco for human consumption. [Background technology]

[0002] Many smoking articles have been proposed over the years as an improvement to tobacco combustion or as an alternative to tobacco combustion-based smoking products. Exemplary alternatives include devices that burn solid or liquid fuel to transfer heat to tobacco, or that use chemical reactions to obtain such a heat source. Many references have proposed a variety of smoking articles that produce flavored vapor, visible aerosol, or a mixture of flavored vapor and visible aerosol. These proposed types of smoking articles include a tubular section or a longitudinally extending air passage.

[0003] An improvement or alternative to smoking articles has typically been to obtain the sensations associated with smoking a cigarette, cigar, or pipe without delivering significant amounts of the products of incomplete combustion and pyrolysis. To achieve this goal, numerous smoking products, flavor generators, and medicinal inhalers have been proposed that utilize electrical energy to vaporize or heat volatile substances or that attempt to provide the sensations of smoking a cigarette, cigar, or pipe without burning tobacco.

[0004] Other common examples of smoking articles are described in U.S. Patent No. 3,258,015 to Ellis et al.; U.S. Patent No. 3,356,094 to Ellis et al.; U.S. Patent No. 3,516,417 to Moses; U.S. Patent No. 4,347,855 to Lanzellotti et al.; U.S. Patent No. 4,340,072 to Bolt et al.; U.S. Patent No. 4,391,285 to Burnett et al.; U.S. Patent No. 4,917,121 to Riehl et al.; U.S. Patent No. 4,924,886 to Litzinger; and U.S. Patent No. 5,060,676 to Hearn et al. Many of these types of smoking articles use a combustible fuel source that is burned to provide an aerosol and / or heat an aerosol-forming substance. For example, see the background art cited in U.S. Patent No. 4,714,082 to Banerjee et al. and U.S. Patent No. 4,771,795 to White et al. (these entireties are incorporated herein by reference). See also, for example, U.S. Patent No. 4,756,318 to Clearman et al.; U.S. Patent No. 4,714,082 to Banerjee et al.; U.S. Patent No. 4,771,795 to White et al.; U.S. Patent No. 4,793,365 to Sensabaugh et al.; U.S. Patent No. 4,917,128 to Clearman et al.; U.S. Patent No. 4,961,438 to Korte; U.S. Patent No. 4,966,171 to Serrano et al.; U.S. Patent No. 4,969,476 to Bale et al.; U.S. Patent No. 4,991,606 to Serrano et al.; U.S. Patent No. 4,991,606 to Farrier et al. No. 5,020,548 to Clearman et al.; U.S. Pat. No. 5,033,483 to Clearman et al.; U.S. Pat. No. 5,040,551 to Schlatter et al.; U.S. Pat. No. 5,050,621 to Creighton et al.; U.S. Pat. No. 5,065,776 to Lawson; U.S. Pat. No. 5,076,296 to Nystrom et al.; U.S. Pat. No. 5,076,297 to Farrier et al.; U.S. Pat. No. 5,099,861 to Clearman et al.; U.S. Pat. No. 5,105,835 to Drewett et al.; U.S. Pat. No. 5,105,837 to Barnes et al.;U.S. Patent No. 5,115,820 to Hauser et al.; U.S. Patent No. 5,148,821 to Best et al.; U.S. Patent No. 5,159,940 to Hayward et al.; U.S. Patent No. 5,178,167 to Riggs et al.; U.S. Patent No. 5,183,062 to Clearman et al.; U.S. Patent No. 5,211,684 to Shannon et al.; U.S. Patent No. 5,240,014 to Deevi et al.; U.S. Patent No. 5,240,016 to Nichols et al.; U.S. Patent No. 5,240,016 to Clearman et al. See also the types of smoking articles described in U.S. Patent Nos. 345,955; 5,551,451 to Riggs et al.; 5,595,577 to Bensalem et al.; 5,819,751 to Barnes et al.; 6,089,857 to Matsuura et al.; 6,095,152 to Beven; 6,578,584 to Beven; and 6,730,832 to Dominguez, which are incorporated herein by reference in their entireties. Additionally, specialty cigarettes using carbonaceous fuel elements are marketed by R.J. Reynolds Tobacco Company under the trade names "Premier" and "Eclipse." See, e.g., Chemical and Biological Studies on New Cigarette Prototypes that Heat Instead of Burn Tobacco, R.J. Reynolds Tobacco Company Monograph (1988), and cigarettes of the type described in Inhalation Toxicology, 12:5, pp. 1-58 (2000). See also U.S. Patent Application Publication No. 2005 / 0274390 to Banerjee et al., U.S. Patent Application Publication No. 2007 / 0215167 to Crooks et al., U.S. Patent Application Publication No. 2010 / 0065075 to Banerjee et al., and U.S. Patent Application Publication No. 2012 / 0042885 to Stone et al., the disclosures of which are incorporated herein by reference in their entireties.

[0005] Certain proposed cigarette-shaped tobacco products are said to use tobacco in a form that is intended to be less completely burned. See, e.g., U.S. Patent No. 4,836,225 to Sudoh; U.S. Patent No. 4,972,855 to Kuriyama et al.; and U.S. Patent No. 5,293,883 to Edwards (incorporated herein by reference in their entireties). Still other types of smoking articles, such as those that produce flavored vapor by subjecting tobacco or processed tobacco to heat generated from a chemical or electrical heat source, are disclosed in U.S. Pat. No. 4,848,374 to Chard et al.; U.S. Pat. Nos. 4,947,874 and 4,947,875 to Brooks et al.; U.S. Pat. No. 5,060,671 to Counts et al.; U.S. Pat. No. 5,146,934 to Deevi et al.; U.S. Pat. No. 5,224,498 to Deevi; U.S. Pat. No. 5,285,798 to Banerjee et al.; U.S. Pat. No. 5,357,984 to Farrier et al.; U.S. Pat. No. 5,593,792 to Farrier et al.; U.S. Pat. No. 5,369,723 to Counts; U.S. Pat. No. 5,692,525 to Counts et al.; U.S. Pat. No. 5,369,723 to Counts; U.S. Pat. No. 5,692,525 to Counts et al.; U.S. Pat. No. 5,369,723 to Collins et al.; U.S. Pat. No. 5,369,723 to Counts; U.S. Pat. No. 5,369,723 to Collins et al. ... No. 865,185; U.S. Patent No. 5,878,752 to Adams et al.; U.S. Patent No. 5,880,439 to Deevi et al.; U.S. Patent No. 5,915,387 to Baggett et al.; U.S. Patent No. 5,934,289 to Watkins et al.; U.S. Patent No. 6,033,623 to Deevi et al.; U.S. Patent No. 6,053,176 to Adams et al.; U.S. Patent No. 6,164,287 to White; U.S. Patent No. 6,289,898 to Fournier et al.; U.S. Patent No. 6,615,840 to Fournier et al.; U.S. Patent Application Publication No. 2003 / 0131859 ​​to Li et al.; U.S. Patent Application Publication No. 2005 / 0016549 to Banerjee et al.; and U.S. Patent Application Publication No. 2006 / 0185687 to Hearn et al. (each of which is incorporated herein by reference in its entirety).

[0006] Certain attempts have been made to deliver vapors, sprays or aerosols, including those that carry or incorporate flavors and / or nicotine. See, for example, U.S. Pat. No. 4,190,046 to Virag; U.S. Pat. No. 4,284,089 to Ray; U.S. Pat. No. 4,635,651 to Jacobs; U.S. Pat. No. 4,735,217 to Gerth et al.; U.S. Pat. No. 4,800,903 to Ray et al.; U.S. Pat. No. 5,388,574 to Ingebrethsen et al.; U.S. Pat. No. 5,799,663 to Gross et al.; U.S. Pat. No. 6,532,965 to Abhulimen et al.; and U.S. Pat. No. 6,598,607 to Adiga et al.; European Patent No. 1,618,803 to Hon; devices of the type shown in U.S. Pat. No. 7,117,867 to Cox et al.; and devices shown on the website www.e-cig.com (all of which are incorporated herein by reference in their entireties).

[0007] Even more representative cigarettes or smoking articles that have been described, and in some cases are commercially available, include U.S. Pat. No. 4,922,901 to Brooks et al.; U.S. Pat. No. 5,249,586 to Morgan et al.; U.S. Pat. No. 5,388,594 to Counts et al.; U.S. Pat. No. 5,666,977 to Higgins et al.; U.S. Pat. No. 6,196,218 to Voges; U.S. Pat. No. 6,810,883 to Felter et al.; U.S. Pat. No. 6,854,461 to Nichols; U.S. Pat. No. 7,832,410 to Hon; U.S. Pat. No. 7,513,253 to Kobayashi; U.S. Pat. No. 7,726,320 to Robinson et al.; U.S. Pat. No. 7,899 to Hamano; No. 6,006; U.S. Patent No. 6,772,756 to Shayan; U.S. Patent Application Publication No. 2009 / 0095311 to Hon; U.S. Patent Application Publication Nos. 2006 / 0196518, 2009 / 0126745, and 2009 / 0188490 to Hon; U.S. Patent Application Publication No. 2009 / 0272379 to Thorens et al.; Monse Examples of such methods include those described in U.S. Patent Application Publication Nos. 2009 / 0260641 and 2009 / 0260642 to Oglesby et al., U.S. Patent Application Publication Nos. 2008 / 0149118 and 2010 / 0024834 to Oglesby et al., U.S. Patent Application Publication No. 2010 / 0307518 to Wang, and WO2010 / 091593 to Hon. See also U.S. Patent Application Publication No. D657,047 to Minskoff et al., and U.S. Patent Application Publication Nos. 2011 / 0277757, 2011 / 0277760, and 2011 / 0277764 to Terry et al.Still further examples include ACCORD®; HEATBAR®; HYBRID CIGARETTE®, VEGAS®; E-GAR®; C-GAR®; E-MYSTICK®; IOLITE® Vaporizer, GREEN SMOKE®, BLU® Cigs, WHITE CLOUD® Cirrus, V2CIGS®, SOUTH BEACH SMOKE®, SMOKETIP®, SMOKE STIK®, NJOY®, LUCI®, Royal Blues, SMART SMOKER®, SMOKE ASSIST®, Knight Sticks, GAMUCCI®, InnoVapor, SMOKING These include e-cigarette products marketed under the names EVERYWHERE®, Crown7, CHOICE™ NO. 7™, VAPORKING®, EPUFFER®, LOGIC™ ecig, VAPOR4LIFE®, NICOTEK®, METRO®, VUSE®, and PREMIUM™. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent No. 3,258,015 [Patent Document 2] U.S. Patent No. 3,356,094 [Patent Document 3] U.S. Patent No. 3,516,417 [Patent Document 4] U.S. Patent No. 4,347,855 [Patent Document 5] U.S. Patent No. 4,340,072 [Patent Document 6] U.S. Patent No. 4,391,285 [Patent Document 7] U.S. Patent No. 4,917,121 [Patent Document 8] U.S. Patent No. 4,924,886 [Patent Document 9] U.S. Patent No. 5,060,676 [Patent Document 10] U.S. Patent No. 4,714,082 [Patent Document 11] U.S. Patent No. 4,771,795 [Patent Document 12] U.S. Patent No. 4,756,318 [Patent Document 13] U.S. Patent No. 4,793,365 [Patent Document 14] U.S. Patent No. 4,917,128 [Patent Document 15] U.S. Patent No. 4,961,438 [Patent Document 16] U.S. Patent No. 4,966,171 [Patent Document 17] U.S. Patent No. 4,969,476 [Patent Document 18] U.S. Patent No. 4,991,606 [Patent Document 19] U.S. Patent No. 5,020,548 [Patent Document 20] U.S. Patent No. 5,033,483 [Patent Document 21] U.S. Patent No. 5,040,551 [Patent Document 22] U.S. Patent No. 5,050,621 [Patent Document 23] U.S. Patent No. 5,065,776 [Patent Document 24] U.S. Patent No. 5,076,296 [Patent Document 25] U.S. Patent No. 5,076,297 [Patent Document 26] U.S. Patent No. 5,099,861 [Patent Document 27] U.S. Patent No. 5,105,835 [Patent Document 28] U.S. Patent No. 5,105,837 [Patent Document 29] U.S. Patent No. 5,115,820 [Patent Document 30] U.S. Patent No. 5,148,821 [Patent Document 31] U.S. Patent No. 5,159,940 [Patent Document 32] U.S. Patent No. 5,178,167 [Patent Document 33] U.S. Patent No. 5,183,062 [Patent Document 34] U.S. Patent No. 5,211,684 [Patent Document 35] U.S. Patent No. 5,240,014 [Patent Document 36] U.S. Patent No. 5,240,016 [Patent Document 37] U.S. Patent No. 5,345,955 [Patent Document 38] U.S. Patent No. 5,551,451 [Patent Document 39] U.S. Patent No. 5,595,577 [Patent Document 40] U.S. Patent No. 5,819,751 [Patent Document 41] U.S. Patent No. 6,089,857 [Patent Document 42] U.S. Patent No. 6,095,152 [Patent Document 43] U.S. Patent No. 6,578,584 [Patent Document 44] U.S. Patent No. 6,730,832 [Patent Document 45] US Patent Application Publication No. 2005 / 0274390 [Patent Document 46] US Patent Application Publication No. 2007 / 0215167 [Patent Document 47] US Patent Application Publication No. 2010 / 0065075 [Patent Document 48] US Patent Application Publication No. 2012 / 0042885 [Patent Document 49] U.S. Patent No. 4,836,225 [Patent Document 50] U.S. Patent No. 4,972,855 [Patent Document 51] U.S. Patent No. 5,293,883 [Patent Document 52] U.S. Patent No. 4,848,374 [Patent Document 53] U.S. Patent No. 4,947,874 [Patent Document 54] U.S. Patent No. 4,947,875 [Patent Document 55] U.S. Patent No. 5,060,671 [Patent Document 56] U.S. Patent No. 5,146,934 [Patent Document 57] U.S. Patent No. 5,224,498 [Patent Document 58] U.S. Patent No. 5,285,798 [Patent Document 59] U.S. Patent No. 5,357,984 [Patent Document 60] U.S. Patent No. 5,593,792 [Patent Document 61] U.S. Patent No. 5,369,723 [Patent Document 62] U.S. Patent No. 5,692,525 [Patent Document 63] U.S. Patent No. 5,865,185 [Patent Document 64] U.S. Patent No. 5,878,752 [Patent Document 65] U.S. Patent No. 5,880,439 [Patent Document 66] U.S. Patent No. 5,915,387 [Patent Document 67] U.S. Patent No. 5,934,289 [Patent Document 68] U.S. Patent No. 6,033,623 [Patent Document 69] U.S. Patent No. 6,053,176 [Patent Document 70] U.S. Patent No. 6,164,287 [Patent Document 71] U.S. Patent No. 6,289,898 [Patent Document 72] U.S. Patent No. 6,615,840 [Patent Document 73] US Patent Application Publication No. 2003 / 0131859 [Patent Document 74] US Patent Application Publication No. 2005 / 0016549 [Patent Document 75] US Patent Application Publication No. 2006 / 0185687 [Patent Document 76] U.S. Patent No. 4,190,046 [Patent Document 77] U.S. Patent No. 4,284,089 [Patent Document 78] U.S. Patent No. 4,635,651 [Patent Document 79] U.S. Patent No. 4,735,217 [Patent Document 80] U.S. Patent No. 4,800,903 [Patent Document 81] U.S. Patent No. 5,388,574 [Patent Document 82] U.S. Patent No. 5,799,663 [Patent Document 83] U.S. Patent No. 6,532,965 [Patent Document 84] U.S. Patent No. 6,598,607 [Patent Document 85] European Patent No. 1,618,803 [Patent Document 86] U.S. Patent No. 7,117,867 [Patent Document 87] U.S. Patent No. 4,922,901 [Patent Document 88] U.S. Patent No. 5,249,586 [Patent Document 89] U.S. Patent No. 5,388,594 [Patent Document 90] U.S. Patent No. 5,666,977 [Patent Document 91] U.S. Patent No. 6,196,218 [Patent Document 92] U.S. Patent No. 6,810,883 [Patent Document 93] U.S. Patent No. 6,854,461 [Patent Document 94] U.S. Patent No. 7,832,410 [Patent Document 95] U.S. Patent No. 7,513,253 [Patent Document 96] U.S. Patent No. 7,726,320 [Patent Document 97] U.S. Patent No. 7,896,006 [Patent Document 98] U.S. Patent No. 6,772,756 [Patent Document 99] US Patent Application Publication No. 2009 / 0095311 [Patent Document 100] US Patent Application Publication No. 2006 / 0196518 [Patent Document 101] US Patent Application Publication No. 2009 / 0126745 [Patent Document 102] US Patent Application Publication No. 2009 / 0188490 [Patent Document 103] US Patent Application Publication No. 2009 / 0272379 [Patent Document 104] US Patent Application Publication No. 2009 / 0260641 [Patent Document 105] US Patent Application Publication No. 2009 / 0260642 [Patent Document 106] US Patent Application Publication No. 2008 / 0149118 [Patent Document 107] US Patent Application Publication No. 2010 / 0024834 [Patent Document 108] US Patent Application Publication No. 2010 / 0307518 [Patent Document 109] International Publication No. 2010 / 091593 [Patent Document 110] U.S. Patent No. D657,047 [Patent Document 111] US Patent Application Publication No. 2011 / 0277757 [Patent Document 112] US Patent Application Publication No. 2011 / 0277760 [Patent Document 113] US Patent Application Publication No. 2011 / 0277764 [Non-patent literature]

[0009] [Non-Patent Document 1] Chemical and Biological Studies on New Cigarette Prototypes that Heat Instead of Burn Tobacco, RJ Reynolds Tobacco Company Monograph (1988) [Non-patent document 2] Inhalation Toxicology, 12:5, p. 1-58 (2000) Summary of the Invention [Problem to be solved by the invention]

[0010] Smoking articles that use tobacco substitutes and that use heat sources other than combusted tobacco-cut filters (to produce tobacco-flavored vapor or visible tobacco-flavored aerosol) have not met with significant commercial success. Articles that produce the smoking flavor and sensation by electrically heating tobacco have, in particular, suffered from inconsistent release of flavors or other inhalable substances. Electrically heated smoking devices have also often been limited by the requirement for an external heating device, which is inconvenient and detracts from the smoking experience. Therefore, it may be desirable to have a smoking article that can provide the smoking sensation of a cigarette, cigar, or pipe without significantly burning tobacco, without the need for a combustion heat source, and without the need to deliver significant amounts of incomplete combustion and pyrolysis products. [Means for solving the problem]

[0011] The present invention provides smoking articles and their use for controllably delivering aerosol precursor components. Disclosed herein are articles incorporating one or more micro-heaters for use in vaporizing or aerosolizing compositions to provide a desired result to a consumer of the article, such as achieving an experience substantially similar to smoking a conventional cigarette, or achieving the delivery of flavors, etc.

[0012] In various embodiments, a smoking article according to the present disclosure may include a power source and a micro-heater electrically connected to the power source. The micro-heater may be characterized as a micro-electromechanical systems (MEMS)-based heater. Alternatively, the micro-heater may be characterized as a thin-film heater.

[0013] The properties of useful microheaters according to the present disclosure may vary. In various embodiments, the microheater may include a patterned conductive material. For example, the conductive material may be selected from the group consisting of elemental metals, metal alloys, silicon, ceramics, carbon, carbides, nitrides, and combinations thereof. The microheater may include a support layer on which a conductive material is patterned. For example, the conductive material may be a printed layer overlying the support layer. Alternatively, the conductive material may be an etched layer overlying the support layer. Preferably, the support layer is temperature stable over a defined temperature range, such as from about 125°C to about 750°C. In certain embodiments, the support layer may be silicon-based, e.g., silicon nitride. The microheater may include a protective layer overlying the patterned conductive material. Preferably, the protective layer is temperature stable over a defined temperature range, such as from about 125°C to about 750°C. In certain embodiments, the protective layer may be silicon-based, e.g., silicon dioxide. As can be appreciated from the foregoing, microheaters useful in the articles of the present disclosure may comprise two or more layers. For example, the microheaters may be characterized as including a conductive material sandwiched between two layers or two membranes. The microheaters disclosed herein may also have defined dimensions. For example, the microheaters may have a length of about 3 mm or less and a width of about 3 mm or less. More specifically, the microheaters may have a length of about 0.5 mm to about 3 mm and a width of about 0.5 mm to about 3 mm.

[0014] The microheaters for use in the articles disclosed herein can be utilized independently of additional components. In other embodiments, the microheaters can be attached to a substrate. Such a substrate can be permanently attached to the article, or the substrate can be removable from the smoking article. Preferably, the substrate can be formed from an electrically insulating material.

[0015] In certain embodiments, a smoking article according to the present disclosure may include multiple micro-heaters. If desired, the multiple micro-heaters may be arranged in series within the smoking article. Thus, the arranged micro-heaters may be adapted to be heated in a predetermined order (e.g., sequentially) or in a prescribed pattern (e.g., two or more micro-heaters heated separately or two or more micro-heaters heated in series).

[0016] The smoking article disclosed herein may further include an aerosol precursor composition. In certain embodiments, the microheater may be operably disposed within the smoking article so as to be in substantial contact with the aerosol precursor composition. Furthermore, the aerosol precursor composition may exist in various forms, such as a liquid or gel form at ambient conditions. Optionally, the aerosol precursor composition may alternatively be in a solid form at ambient conditions. In certain embodiments, the aerosol precursor composition may be in the form of a gel coated on the microheater.

[0017] In other embodiments, the aerosol precursor composition may be provided in a reservoir such that the aerosol precursor composition is spaced from the microheater. The article may therefore include a controller adapted to cause the microheater to deliver a predetermined amount of the aerosol precursor composition. In certain embodiments, the microheater may be thermally coupled to a chamber formed from a wall, the chamber adapted to receive a predetermined amount of the aerosol precursor composition through an opening in the chamber. The chamber may include an opening adapted for vapor exit from the chamber and / or an opening suitable for air filtering. In certain embodiments, the chamber may have a volume of about 0.2 ml to about 1 ml. Such embodiments may be adapted to individually heat separate compositions or components thereof. For example, the aerosol precursor composition may include multiple individual components, and the smoking article may include multiple reservoirs each containing the individual components of the aerosol precursor composition, and the smoking article may include multiple chambers adapted to receive predetermined amounts of the individual components of the aerosol precursor composition from the reservoirs.

[0018] In yet further embodiments, the aerosol precursor composition may be coated on, adsorbed onto, or absorbed into a carrier material. Further, the carrier material may be disposed within the article so as to be in substantial contact with the microheater. Optionally, the article may include multiple microheaters in substantial contact with the carrier material.

[0019] The aerosol precursor composition may include a variety of ingredients, for example, the composition may include one or more of a polyhydric alcohol, a drug, a tobacco-derived substance, and a flavoring.

[0020] The power source may be selected from the group consisting of a battery, a capacitor, and combinations thereof. Additionally, the article may include a control component that directs current from the power source to the microheater. For example, the control component may include a puff-actuated sensor or a capacitive sensor.

[0021] In further embodiments, the smoking article can be characterized with respect to the atomizer used therein. For example, the smoking article can include a micro-heater that is integral with the atomizer. More specifically, the atomizer can include a chamber defined by a wall, a cover, and a protective layer overlying the micro-heater. Furthermore, one or both of the wall and the cover can include a plurality of openings sized to allow vapor to pass through but not liquid.

[0022] Therefore, the present disclosure may also include an atomizer suitable for use in an electrical smoking article. For example, the atomizer may include a chamber formed from a chamber wall, a cover, and a micro-heater. The chamber wall and the cover may be integral or may be attached to a support layer or protective layer of the micro-heater as discussed herein. One or both of the chamber wall and the cover may include a plurality of openings sized to allow vapor to pass through but not liquid.

[0023] In further embodiments, the present disclosure may relate to a method of forming an aerosol in a smoking article. For example, the method may include initiating an electric current from a power source within the smoking article to a micro-heater within the smoking article, thereby heating the micro-heater and an aerosol precursor composition in contact with the micro-heater.

[0024] In certain embodiments, the smoking article utilized in this method may include multiple microheaters, and two or more of the microheaters may be heated simultaneously. Furthermore, the aerosol precursor composition may include two or more individual components, and the individual components of the aerosol precursor composition may be heated separately by the microheaters. Furthermore, the microheaters may receive current from a power source under different conditions, such that the microheaters are heated to different temperatures or for different periods of time. In some embodiments, two or more microheaters may be heated sequentially.

[0025] Optionally, the aerosol precursor composition may be coated on, adsorbed to, or absorbed into a carrier material. Moreover, prior to the step of activating an electric current, the method may further comprise inserting a carrier material into the smoking article. In a further embodiment, the microheater may be attached to a substrate. Similarly, prior to the step of activating an electric current, the method may further comprise inserting a substrate into the smoking article. Advantageously, the aerosol precursor composition may be coated on a microheater attached to a substrate. In a further embodiment, the method may further comprise initiating a flow of the aerosol precursor composition from a reservoir to a chamber thermally coupled to the microheater, thereby heating the aerosol precursor composition in the chamber.

[0026] The present invention includes, but is not limited to, the following embodiments.

[0027] Embodiment 1: A smoking article comprising a power source and a micro-heater electrically connected to the power source.

[0028] Embodiment 2: The smoking article of any preceding or subsequent embodiment, wherein the microheater is a microelectromechanical systems (MEMS)-based heater.

[0029] Embodiment 3: The smoking article of any preceding or subsequent embodiment, wherein the micro-heater is a thin film heater.

[0030] Embodiment 4: The smoking article of any preceding or subsequent embodiment, wherein the micro-heater comprises a patterned conductive material.

[0031] Embodiment 5: The smoking article of any preceding or subsequent embodiment, wherein the electrically conductive material is selected from the group consisting of elemental metals, metal alloys, silicon, ceramics, carbon, carbides, nitrides, and combinations thereof.

[0032] Embodiment 6: The smoking article of any preceding or subsequent embodiment, wherein the microheater includes a support layer having a conductive material patterned thereon.

[0033] Embodiment 7: A smoking article according to any preceding or subsequent embodiment, wherein the conductive material is a printed layer laminated to a support layer, or wherein the conductive material is an etched layer laminated to a support layer.

[0034] Embodiment 8: The smoking article of any preceding or subsequent embodiment, wherein the micro-heater comprises a protective layer overlying a patterned conductive material.

[0035] Embodiment 9: The smoking article of any preceding or subsequent embodiment, wherein the support layer or protective layer is temperature stable in a temperature range of about 125°C to about 750°C.

[0036] Embodiment 10: The smoking article of any preceding or subsequent embodiment, wherein the support or protective layer comprises a silicone-based material.

[0037] Embodiment 11: The smoking article of any preceding or subsequent embodiment, wherein the micro-heater comprises two or more layers.

[0038] Embodiment 12: The smoking article of any preceding or subsequent embodiment, wherein the micro-heater comprises a conductive material sandwiched between two membranes.

[0039] Embodiment 13: The smoking article of any preceding or subsequent embodiment, wherein the micro-heater has a length of about 3 mm or less and a width of about 3 mm or less.

[0040] Embodiment 14: The smoking article of any preceding or subsequent embodiment, wherein the micro-heater has a length of about 0.5 mm to about 3 mm and a width of about 0.5 mm to about 3 mm.

[0041] Embodiment 15: The smoking article of any preceding or subsequent embodiment, wherein the micro-heater is attached to a substrate.

[0042] Embodiment 16: A smoking article according to any preceding or subsequent embodiment, wherein the substrate is formed from an electrically insulating material.

[0043] Embodiment 17: A smoking article according to any preceding or subsequent embodiment, comprising a plurality of micro-heaters.

[0044] Embodiment 18: The smoking article of any preceding or subsequent embodiment, further comprising an aerosol precursor composition.

[0045] Embodiment 19: The smoking article of any preceding or subsequent embodiment, wherein the aerosol precursor composition is in the form of a liquid or gel at ambient conditions.

[0046] Embodiment 20: The smoking article of any preceding or subsequent embodiment, wherein the aerosol precursor composition is within a reservoir such that the aerosol precursor composition is spaced from the microheater.

[0047] Embodiment 21: A smoking article according to any preceding or subsequent embodiment, wherein the article comprises a controller adapted to cause the microheater to deliver a predetermined amount of the aerosol precursor composition.

[0048] Embodiment 22: A smoking article according to any preceding or subsequent embodiment, wherein the microheater is thermally coupled to a chamber adapted to receive a predetermined amount of an aerosol precursor composition through an opening in the chamber.

[0049] Embodiment 23: A smoking article according to any preceding or subsequent embodiment, wherein the chamber comprises an opening adapted for the exit of vapor from the chamber.

[0050] Embodiment 24: A smoking article according to any preceding or subsequent embodiment, wherein the chamber has a volume of from about 0.2 ml to about 1 ml.

[0051] Embodiment 25: The smoking article of any preceding or subsequent embodiment, wherein the aerosol precursor composition may be coated on, adsorbed onto, or absorbed into a carrier material, the carrier material being disposed within the article in substantial contact with the micro-heater.

[0052] Embodiment 26: The smoking article of any preceding or subsequent embodiment, wherein the microheater is integral with the atomizer.

[0053] Embodiment 27: A smoking article according to any preceding or subsequent embodiment, wherein the atomizer comprises a chamber defined by a wall, a cover, and a protective layer overlying the micro-heater.

[0054] Embodiment 28: A smoking article according to any preceding or subsequent embodiment, wherein one or both of the wall and cover comprise a plurality of apertures sized to allow vapor to pass through but not liquid.

[0055] Embodiment 29: A method of forming an aerosol in a smoking article, comprising passing an electric current from a power source within the smoking article through a micro-heater within the smoking article, thereby heating the micro-heater and an aerosol precursor composition in contact with the micro-heater.

[0056] Embodiment 30: The method of any preceding or subsequent embodiment, wherein the smoking article comprises a plurality of micro-heaters.

[0057] Embodiment 31: The method of any preceding or subsequent embodiment, wherein the aerosol precursor composition is coated on, adsorbed onto, or absorbed into a carrier material, and further comprising inserting a carrier material into the smoking article prior to the step of activating the electric current.

[0058] Embodiment 32: The method of any preceding or subsequent embodiment, further comprising initiating a flow of the aerosol precursor composition from a reservoir to a chamber thermally coupled to the microheater, thereby heating the aerosol precursor composition in the chamber.

[0059] Embodiment 33: An atomizer suitable for use in an electronic smoking article, comprising a chamber formed from a chamber wall, a cover, and a micro-heater.

[0060] Embodiment 34: The sprayer of any preceding or subsequent embodiment, wherein one or both of the chamber wall and the cover comprise a plurality of openings.

[0061] Embodiment 35: A sprayer according to any preceding or subsequent embodiment, wherein one or more of the plurality of openings is sized to be permeable to vapor but not liquid.

[0062] These and other features, aspects, and advantages of the present disclosure will become apparent when read in conjunction with the following detailed description and the accompanying drawings (briefly described below). The disclosure encompasses any combination of two, three, four, or more of the foregoing embodiments, and any combination of two, three, four, or more features or elements set forth in the present disclosure, whether or not such features and elements are expressly combined in the description of a particular embodiment herein. The present disclosure is to be read holistically, such that any separable features or elements of the disclosed subject matter, in any of its various aspects and embodiments, should be considered combinable unless the context clearly dictates otherwise.

[0063] Having thus described the invention in general terms above, reference is now made to the accompanying drawings, which are not necessarily drawn to scale. [Brief explanation of the drawings]

[0064] [Figure 1] FIG. 1 is a perspective view of an exemplary embodiment of a micro-heater according to the present disclosure. [Figure 2] 1 is a perspective view of an exemplary embodiment of a smoking article according to the present disclosure, with a portion of the outer shell of the article cut away to reveal its internal components. [Figure 3] 1 is a perspective view of an exemplary embodiment of a smoking article according to the present disclosure, the article comprising a control body and a cartridge detachable therefrom. [Figure 4] FIG. 1 is a perspective view of a substrate having a plurality of micro-heaters thereon, according to an exemplary embodiment of the present disclosure. [Figure 5] FIG. 5 is a longitudinal cross-sectional view of the substrate shown in FIG. 4 taken along line AA, showing a microheater housed within a well in the substrate and covered with an aerosol precursor composition. [Figure 6] FIG. 1 is a perspective view of a substrate according to an exemplary embodiment of the present disclosure, wherein the substrate comprises two layers with a plurality of micro-heaters therebetween. [Figure 7]FIG. 1 is a perspective view of an exemplary embodiment of a smoking article according to the present disclosure, wherein the article comprises a unitary body with a hinged door that provides access to a cavity therein that receives a substrate containing an aerosol precursor composition and is lined with a plurality of microheaters. [Figure 8] FIG. 1 is a perspective view of a sprayer according to an exemplary embodiment of the present disclosure. [Figure 9] FIG. 10 is a perspective view of a further atomizer according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0065] The present invention will now be described in more detail hereinafter with reference to exemplary embodiments thereof. These exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Indeed, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are presented so that this disclosure will satisfy applicable legal requirements. As used in this specification and the appended claims, the singular forms "a," "an," "this," and "the" include the plural forms unless the context clearly contradicts otherwise.

[0066] The present invention provides an article that uses electrical energy to heat a material (preferably without burning the material to any extent) to form an inhalable substance, and the article is small enough to be considered a "handheld" device. In certain embodiments, the article may be specifically characterized as a smoking article. As used herein, this term refers to an article that provides the taste and / or sensation (e.g., hand or mouth sensation) of smoking a cigarette, cigar, or pipe without substantial combustion of any of the article's components. The term smoking article does not necessarily indicate that the article produces smoke in the sense of a combustion or pyrolysis by-product during operation. Instead, smoking refers to the physical activity of an individual in using the article, e.g., holding the article, drawing on one end of the article, and inhaling from the article. In further embodiments, the article of the present invention may be characterized as a vapor-generating product, an aerosolized product, or a drug delivery product. Thus, the article may be configured to provide one or more substances in an inhalable form. In other embodiments, the inhalable substance may be substantially in vapor form (i.e., a substance that is in the gas phase at a temperature below its critical point). In other embodiments, the inhalable substance may be in the form of an aerosol (i.e., a suspension of solid particles or liquid droplets in a gas). The physical form of the inhalable substance need not be limited to the nature of the article of the present invention, but will depend on the nature of the medium and the inhalable substance itself, depending on whether it exists in a vapor state or an aerosol state. In some embodiments, the terms may be interchangeable. Thus, for simplicity, it will be understood that the terms used to describe the present invention are interchangeable unless otherwise stated.

[0067] In one aspect, the present invention provides a smoking article. The smoking article generally comprises multiple components provided within an elongated body, which may be in the form of a single, unitary shell or two or more separable pieces. For example, a smoking article according to one embodiment may comprise a shell (i.e., an elongated body) that may be substantially tubular in shape, such as to mimic the shape of a traditional cigarette or cigar. All components of the smoking article may reside within the shell (one or more of which may be replaceable). In other embodiments, the smoking article may comprise two connected and separable shells. For example, a control body may comprise one or more reusable components and a shell having an end that removably couples to a cartridge. The cartridge may comprise one or more disposable components and a shell having an end that removably couples to the control body. More specific arrangements of components within a single shell or within a separable control body and cartridge will be apparent in light of the further disclosure provided herein.

[0068] A smoking article according to the present invention may comprise some combination of a power source (i.e., a power source), one or more control components (e.g., for controlling / activating / regulating the flow of power from the power source to one or more additional components of the article), a heater component, and an aerosol precursor component. The smoking article may further comprise a defined air flow path through the article, such that an aerosol generated by the article can be drawn therefrom by a user inhaling the article. The arrangement of components within the article may vary. In certain embodiments, the aerosol precursor component may be positioned near the end of the article closest to the user's mouth, thereby maximizing aerosol delivery to the user. However, other configurations are not excluded. In general, the heater component may be positioned sufficiently close to the aerosol precursor component so that heat from the heater component can volatilize the aerosol precursor (as well as one or more flavorings, medicinal agents, or the like that may be provided for delivery to the user) and form an aerosol for delivery to the user. When the heating element heats the aerosol precursor components, an aerosol (alone or further comprising the inhalable substance) is formed, emitted, or generated in a physical form suitable for inhalation by a consumer. It should be noted that the foregoing terms are meant to be interchangeable. Thus, the terms "emit," "generate," and "form" may be interchangeable; the terms "emit," "generate," and "form" may be interchangeable; the terms "emit," "generate," and "form" may be interchangeable; the terms "emitted," "generated," and "formed" may be interchangeable. Specifically, the inhalable substance is emitted as a vapor or an aerosol or a mixture thereof.

[0069] Smoking articles according to the present invention comprise a heating element that heats aerosol precursor components to generate an aerosol for inhalation by a user. Smoking articles as described herein may be particularly characterized by comprising a micro-heater as the heating element. In particular, the micro-heater may be electrically connected to a power source, as further described herein. The smoking article may comprise only a single micro-heater. However, in other embodiments, the smoking article may comprise multiple micro-heaters. Thus, while it is understood that the present disclosure may describe a smoking article in terms of "a" micro-heater or "the" micro-heater, the disclosure is meant to encompass embodiments in which the smoking article comprises multiple micro-heaters.

[0070] In some embodiments, the microheater used in the smoking articles described herein can be characterized as a microelectromechanical system (MEMS)-based heater. MEMS-based heaters are currently used in ultra-small microsensors such as wind sensors, humidity sensors, and gas sensors. Such MEMS-based microheaters can radiate heat by applying an electric current to a resistor and can offer advantages such as low power input requirements and extremely short response times. MEMS-based microheaters are highly advantageous in smoking articles as described herein because they can provide low-voltage and / or low-power device functionality.

[0071] The micro-heaters used in the smoking articles described herein may also be characterized as thin film heaters or hot film heaters. This may be characterized by the physical properties of the micro-heater, which may comprise a conductive material that may be specifically provided in the form of a film (i.e., a conductive layer). In certain embodiments, the conductive material may be patterned. In other words, the conductive material may be present in the micro-heater in a specific pattern; thus, the term refers to the physical properties of the finished micro-heater and is not limited by the method of fabricating the micro-heater. The thickness of the conductive layer may vary, for example, about 5 μm or less, about 4 μm or less, about 3 μm or less, about 2 μm or less, about 1 μm or less, about 0.75 μm or less, about 0.5 μm or less, about 0.25 μm or less, about 0.1 μm or less, or about 0.075 μm or less. In other embodiments, the conductive layer can have a thickness of about 0.01 μm to about 5 μm, about 0.05 μm to about 3 μm, about 0.1 μm to about 2.5 μm, about 0.2 μm to about 2 μm, or about 0.5 μm to about 1 μm.

[0072] The conductive material used in the microheater can include nearly any material that is conductive within the size ranges discussed above and suitable for thin film formation. For example, the conductive material can be selected from the group consisting of elemental metals, metal alloys, silicon (including single crystal silicon and polycrystalline silicon), ceramics, carbon, carbides, nitrides, and combinations thereof. In more specific embodiments, the conductive material can be formed from platinum, gold, silver, copper, aluminum, tungsten, zinc, nickel, titanium, nichrome, silicon carbide, polycrystalline silicon, single crystal silicon, titanium nitride, and the like. In certain embodiments, elemental metals, such as platinum, can be particularly beneficial due to their excellent oxidation resistance and long-term stability. Thin film microheaters according to the present disclosure can exhibit high levels of durability and stability, which may be preferable to hot wires, which are more prone to breakage and less stable.

[0073] In addition to the conductive layer, the microheater according to the present disclosure may also include a support layer. In particular, a conductive material may be patterned on such a support layer. The support layer is preferably formed of a material that is temperature stable under the heater operating temperatures. For example, the support layer may be temperature stable at temperatures of about 150°C or higher, about 200°C or higher, about 300°C or higher, about 400°C or higher, or about 500°C or higher. In other embodiments, the support layer may be temperature stable in a temperature range of about 125°C to about 750°C, about 150°C to about 650°C, or about 175°C to about 500°C. In some embodiments, the support layer may be formed of a ceramic material, particularly a silicon-based material. One specific example of a support layer material is a silicon nitride material. However, other materials, such as glass or quartz, may also be used. Certain thermoplastic materials, such as cyclic olefin copolymers (COC), may also be used. The support layer may be formed of an insulating material or include an insulating layer.

[0074] The microheater according to the present disclosure may further include a protective layer overlying the conductive layer. The protective layer is preferably formed from a material that is temperature stable and thermally radiative and / or thermally conductive at the operating temperatures of the microheater. For example, the protective layer may be temperature stable at temperatures of about 150°C or higher, about 200°C or higher, about 300°C or higher, about 400°C or higher, or about 500°C or higher. In other embodiments, the protective layer may be temperature stable at temperatures ranging from about 125°C to about 750°C, from about 150°C to about 650°C, or from about 175°C to about 500°C. In some embodiments, the protective layer may be in direct contact with the aerosol precursor composition or its components. Therefore, it is preferable for the protective layer to be substantially chemically unreactive with various compounds that may be contained in the aerosol precursor material. Substantially chemically non-reactive means that any chemical reaction between the protective layer and the components of the aerosol precursor material is sufficiently limited so that the protective layer is not breached, thereby allowing the aerosol precursor composition to indirectly contact the conductive layer of the microheater. Alternatively, the phrase means that any chemical reaction between the protective layer and the components of the aerosol precursor material is sufficiently limited so that compounds present in the protective layer are not released (or new compounds are formed) and thereby combined with the formed aerosol for inhalation by the consumer. In some embodiments, the support layer may be formed from a ceramic material, particularly a silicon-based material. One particular example of a support layer material is a silicon dioxide material. However, other materials, such as glass or quartz, may also be used.

[0075] The microheater may be particularly characterized as a multilayer article. Specifically, the microheater may include two or more layers. In other embodiments, the microheater may be characterized as including a conductive material sandwiched between two layers or two membranes. The thickness of additional layers, such as support layers and protective layers, may vary depending on the application. In some embodiments, the additional layers may be similar in size to the conductive layer. In other embodiments, the additional layers may be thicker than the conductive layer, e.g., each independently having a thickness of about 0.5 mm or less, about 0.75 mm or less, about 1 mm or less, about 1.5 mm or less, about 2 mm or less, or about 5 mm or less.

[0076] The microheater, in its functional configuration, may also be characterized with respect to its additional dimensions. Specifically, the microheater may each independently have a length and width of about 5 mm or less, about 4 mm or less, about 3 mm or less, or about 2 mm or less. In other embodiments, the length and width of the microheater may each independently be about 0.25 mm to about 5 mm, about 0.5 mm to about 3 mm, about 0.6 mm to about 2.5 mm, about 0.7 mm to about 2 mm, or about 0.75 mm to about 1.5 mm.

[0077] An exemplary embodiment of a microheater that can be used in accordance with the present disclosure is shown in FIG. 1. As can be seen, the microheater 50 is formed from a support layer 510, a protective layer 540, and a patterned conductive layer 520 sandwiched between the support layer and the protective layer. Each layer can be formed from materials as described herein and have dimensions as described herein. The microheater also includes terminals 530 extending from the conductive layer and providing electrical contact between the microheater (particularly the conductive material) and additional electrical components of the articles described herein, including various control components and power sources. Preferably, the microheater is disposed within an article as described herein, such that the terminals do not contact the aerosol precursor composition. Additionally, the microheater may further include components designed to space the terminals from portions of the protective layer that contact the aerosol precursor composition for aerosol formation. As illustrated, the protective layer is partially transparent, but microheaters useful as described herein need not necessarily be transparent; such a characteristic may vary depending on the materials utilized. Similarly, the support layer and protective layer may have the same or different dimensions, and the patterning of the conductive layer may vary.

[0078] Microheaters useful in smoking articles such as those described herein can be prepared by a variety of suitable processes. For example, low-pressure chemical vapor deposition (LPCVD) can be used to perform layer-by-layer growth of the microheater. More specifically, a support layer can be deposited on a build substrate (e.g., a silicon wafer, a ceramic, e.g., a metal nitride, quartz, or glass) by LPCVD. A conductive material can then be deposited on the support layer, also by LPCVD. This conductive layer can be patterned as needed to provide desired performance characteristics for the microheater. For example, reactive ion etching (REI) can be used. Electrical contacts can be formed, for example, using a sputtering process to provide a means for electrical contact of the conductive material. A protective layer can be formed on the conductive layer by, for example, plasma enhanced chemical vapor deposition (PECVD). The completed microheater can be removed from the build substrate as needed. For example, anisotropic etching by a deep REI process can be used to remove part or all of the silicon build substrate. Furthermore, the stacked microheater can be packaged, for example, to provide easy access to electrical contacts while also providing additional protection for the functional components of the microheater. For example, packaging may be used to hermetically seal the micro-heater within a thermally stable and thermally conductive material.

[0079] Another method for preparing a microheater useful in the articles of the present invention may involve a metal evaporation process to deposit a conductive layer on a support layer. If necessary, an adhesive layer may be applied prior to the metal evaporation step. Patterning of the conductive material may be performed using a photoresist by standard photolithography techniques (e.g., Shipley-1818), which may include spin-coating the photoresist onto the conductive layer, soft-baking (e.g., at a temperature of about 65°C) to remove the photoresist solvent, aligning the applied photoresist, for example, in a mask aligner, exposing the conductive layer to light while applying pressure with a desired mask, such as with a UV lamp, developing the patterned photoresist with an appropriate developer (e.g., commercially available from Shipley), and hard-baking (e.g., at a temperature of about 90°C) to harden the photoresist. The previously exposed conductive material may be removed by applying a photoresist and etching with an appropriate solvent. The photoresist may then be removed using an appropriate solvent. Such a process may be characterized as subtractive shaping, and the formed microheater may be generally, or the conductive layer specifically, described as a subtractively shaped article or layer.

[0080] Various printing techniques may be used to prepare the microheaters. Specifically, inkjet-type printing techniques may be utilized to systematically deposit conductive material in a desired pattern. This may be particularly useful for forming a conductive layer on a support layer, which may itself be relatively thin, without the need for an additional build substrate. Such techniques, in which the conductive material is a printed layer deposited on a support layer, may be characterized as additive manufacturing, and the formed microheater in general, or the conductive layer in particular, may be described as an additively manufactured article or layer.

[0081] The foregoing processes are only examples of the types of processes that may be used to prepare micro-heaters for use in accordance with the present disclosure and should not be considered limiting of the micro-heaters that may be used in the articles described herein. Additionally, stable micro-heaters for use as described herein are commercially available, for example, from Kebaili Corporation (Irvine, CA, www.kebaili.com).

[0082] In further embodiments, microheaters for use in the devices of the present disclosure may be chemical in nature, more specifically, the microheaters may provide heating based on chemical reactions rather than based on electrical resistance heating.

[0083] The microheaters used in the described articles can offer several advantages over the use of known heating elements. Such microheaters can provide highly energy-efficient electrical heating, especially when a defined amount of material to be heated (e.g., an aerosol precursor composition) is delivered to the microheater in a controlled manner. The microheaters can also easily achieve highly precise aerosol chemistry in a controlled manner.

[0084] Smoking articles as described herein may generally include a power source that provides sufficient current to provide various functions for the article, such as microheater power, indicator power, etc. The power source may take various forms. Preferably, the power source is capable of delivering sufficient power to rapidly heat the microheater, generate aerosol, and power the article throughout use for a desired period of time. The power source is preferably sized to fit conveniently within the article. Examples of useful power sources include, preferably, rechargeable lithium-ion batteries (e.g., rechargeable lithium-manganese dioxide batteries). Specifically, lithium polymer batteries may be used. Other types of batteries, such as N50-AAA CADNICA nickel-cadmium cells, may also be used. Still further examples of batteries that may be used in accordance with the present invention are described in U.S. Patent Application Publication No. 2010 / 0028766, the disclosure of which is incorporated herein by reference in its entirety. Thin-film batteries may be used in certain embodiments of the present invention. While any of these batteries or combinations thereof can be used for the power source, rechargeable batteries are preferred due to the cost and disposability associated with disposable batteries. In embodiments in which disposable batteries are provided, the smoking article may include access means for battery removal and replacement. Alternatively, in embodiments using rechargeable batteries, the smoking article may include charging contacts for interaction with corresponding contacts in a conventional recharging unit that extracts power from a standard 120-volt AC wall outlet or other power source, such as an automobile's electrical system or another portable power source, e.g., a USB connection. The means for recharging the battery may be provided in a portable charging case, which may include, for example, a relatively large battery unit capable of providing multiple charges for the relatively small battery present in the smoking article. The article may further include components for providing a contactless, inductive recharging system, so that the article can be charged without physically connecting to an external power source. Accordingly, the article may include components that facilitate the transfer of energy from an electromagnetic field to a rechargeable battery within the article.

[0085] In further embodiments, the power source may also include a capacitor. The capacitor may be rechargeable more quickly than a battery, being charged between puffs and allowing the battery to discharge into the capacitor at a slower rate than would be possible if the battery were used to directly power the heating element. For example, a supercapacitor, i.e., an electric double layer capacitor (EDLC), may be used separately from or in combination with a battery. When used alone, the supercapacitor may be recharged before each use of the article. Thus, the present invention may also include a charging component that may be attached to the smoking article during use to replenish the supercapacitor.

[0086] The smoking article may further include various power management software, hardware, and / or other electronic control components. For example, such software, hardware, and / or electronic control devices may include those for: battery charging, detecting battery charge and discharge status, performing power saving operations, preventing unintentional or overcharging of the battery, puff counting, puff intervals, puff duration, cartridge status determination, temperature control, etc.

[0087] The term "controller" or "control component" as used herein may encompass a variety of elements useful in the smoking article of the present invention. Furthermore, a smoking article according to the present invention may include one, two, or more control components, which may be combined into a single element or may reside in separate locations within the smoking article, with each control component being utilized to perform a different control aspect. For example, a smoking article may include a control component integrated with or otherwise associated with a battery to control discharge from the battery. The smoking article may also include separate control components to control other aspects of the article. The smoking article may also include a control component in the cartridge to provide specific functions, including data storage (e.g., a microchip containing memory). Alternatively, a single controller may be provided to perform multiple or all control aspects of the article. Similarly, a sensor (e.g., a puff sensor) used in the article may include a control component that controls discharge from a power source in response to a stimulus. The article may also include separate control components to control other aspects of the article. Alternatively, a single controller may be provided or otherwise coupled to a sensor to perform multiple or all control aspects of the article. Thus, various combinations of control devices may be combined in a smoking article of the present invention to provide a desired level of control over all aspects of the device.

[0088] The smoking article may also include one or more controller components useful for controlling the flow of electrical energy from the power source to additional components of the article, such as a resistive heating element. The article may include a control component that activates current from the power source to a microheater, etc. In some embodiments, the article may include a push button that can be coupled to the control circuit for manual control of the flow of power. The one or more push buttons can be substantially flush with the exterior surface of the smoking article.

[0089] Instead of (or in addition to) a push button, an article of the present invention may include one or more control components responsive to a consumer's inhalation on the article (i.e., puff-actuated heating). For example, the article may include a switch that is sensitive to either a change in pressure or a change in air flow when a consumer inhales on the article (i.e., a puff-actuated switch). Other current activation / deactivation mechanisms include a temperature-activated on / off switch or a lip-pressure-activated switch. An exemplary mechanism that may provide such puff-activation capability includes the Model 163PC01D36 silicon sensor (manufactured by the MicroSwitch division of Honeywell, Inc., Freeport, Ill.). Further examples of demand-operated electrical switches that may be used in heating circuits of the present invention are described in U.S. Pat. No. 4,735,217 (Gerth et al.), which is incorporated herein by reference in its entirety. Other suitable differential switches, analog pressure sensors, flow rate sensors, and the like will be apparent to those skilled in the art with knowledge of this disclosure. A pressure-sensing tube or other passageway may be provided providing a fluid connection between the puff-activated switch and the air flow path within the smoking article, so that pressure changes during inhalation are identified by the switch. Further descriptions of current regulating circuits and other control components, including microcontrollers, that may be useful in the smoking articles of the present invention are found in U.S. Patent Nos. 4,922,901, 4,947,874, and 4,947,875 (all to Brooks et al.), U.S. Patent No. 5,372,148 (to McCafferty et al.), U.S. Patent No. 6,040,560 (to Fleischhauer et al.), and U.S. Patent No. 7,040,314 (to Nguyen et al.), all of which are incorporated herein by reference in their entireties.

[0090] Capacitive sensing components may be incorporated into the device in a variety of ways, specifically enabling various types of "power-up" and / or "power-down" for one or more components of the device. Capacitive sensing may encompass the use of any sensor incorporating technology based on capacitive coupling, including, but not limited to, sensors that detect and / or measure proximity, position or movement, humidity, liquid level, pressure, temperature, or acceleration. Capacitive sensing may result from electrical components that provide surface capacitance, projected capacitance, mutual capacitance, or self-capacitance. Capacitive sensors generally can detect anything that is conductive or has a dielectric other than air. For example, a capacitance sensor may replace a mechanical button (i.e., the push button mentioned above) by capacitively replacing it. Thus, one particular application of the capacitance sensor of the present invention is a touch-sensitive capacitance sensor. For example, a touchpad may be present on a smoking article, allowing a user to input various commands. At its most basic, the touchpad can power the heating element in the same manner as a push button, as already described above. In other embodiments, capacitance sensing can be provided near the mouth end of the smoking article, so that lip pressure on the smoking article to take a puff on the article can signal a device that provides power to the heating element. In addition to touch capacitance sensors, motion capacitance sensors, liquid capacitance sensors, and acceleration sensors can be utilized in accordance with the present invention to elicit various responses from the smoking article. Furthermore, photoelectric sensors can also be incorporated into the smoking articles of the present invention.

[0091] The sensors utilized in the articles of the present invention can specifically signal for the flow of power to the heating element, thereby heating the aerosol precursor composition to form a vapor or aerosol for inhalation by the user. The sensors can also provide additional functionality. For example, a "wake-up" sensor may be included. Other sensing methods that provide similar functionality can also be utilized.

[0092] When a consumer inhales on the mouth end of the smoking article, the current actuation means may allow unlimited or uninterrupted flow of current through the resistive heating element to rapidly generate heat. It may also be useful to include a current regulation component to regulate the flow of current through the micro-heater to control the rate and / or duration of heating.

[0093] The current regulation circuit may particularly be time-based. Specifically, such a circuit comprises means for allowing uninterrupted current flow through the heating element over an initial period during inhalation, and timer means for continuing to regulate the current flow until inhalation is complete. Furthermore, regulation may involve simply allowing uninterrupted current flow until the desired temperature is achieved and then completely shutting off the current. The heating element may be reactivated by the consumer initiating another puff on the article (or manually activating a push button, depending on the particular switch embodiment used to activate the heater). Alternatively, subsequent regulation may involve adjusting the current flow through the heating element (including pulse width modulation) to maintain the heating element within a desired temperature range. In some embodiments, the heating element may be energized over a period of about 0.2 seconds to about 5.0 seconds, about 0.3 seconds to about 4.5 seconds, about 0.5 seconds to about 4.0 seconds, about 0.5 seconds to about 3.5 seconds, or about 0.6 seconds to about 3.0 seconds to emit a desired dose of inhalable substance. Further description of such timed current regulation circuits and other control components that may be useful in the smoking articles of the present invention is provided in U.S. Patent Nos. 4,922,901, 4,947,874, and 4,947,875, all to Brooks et al., all of which are incorporated herein by reference in their entireties.

[0094] The control component may be specifically configured to closely control the amount of heat provided to the micro-heater. In some embodiments, the current regulation component may function to terminate current flow to the micro-heater once a predetermined temperature is reached. Such a predetermined temperature may be in a range substantially high enough to volatilize the aerosol precursor composition and any additional inhalable substances and provide a quantity of aerosol at a desired concentration. While the heat required to volatilize the aerosol precursor composition may vary, heating to temperatures of about 120°C or higher, about 130°C or higher, about 140°C or higher, or about 160°C or higher may be particularly useful for the micro-heater. In some embodiments, the heating temperature may be about 180°C or higher, about 200°C or higher, about 300°C or higher, or about 350°C or higher to volatilize a desired amount of the aerosol precursor composition. In further embodiments, the predetermined temperature for aerosol formation may be about 120°C to about 350°C, about 140°C to about 300°C, or about 150°C to about 250°C. The temperature and duration of heating may be controlled by one or more components contained within the controller housing, including a current regulation component that may cycle current to the microheater off and on once a predetermined temperature is achieved to maintain the predetermined temperature for a predetermined period of time.

[0095] Additionally, the current regulation component may cycle the current to the microheater off and on to maintain an initial temperature below the aerosol-forming temperature, and then respond to the current-operated control component to enable an increase in current to achieve a second temperature greater than the initial temperature and at the aerosol-forming temperature. Such control improves the article's response time to aerosol formation, such that aerosol formation begins almost immediately upon the consumer's initiation of puffing. In some embodiments, the initial temperature (which may be characterized as a standby temperature) may be only slightly lower than the aerosol forming temperature defined above. Specifically, this standby temperature may be from about 50°C to about 150°C, from about 70°C to about 140°C, from about 80°C to about 120°C, or from about 90°C to about 110°C.

[0096] In addition to the above elements, the smoking article may also include one or more indicators. Such indicators may be lights (e.g., light-emitting diodes) that can provide indications of multiple aspects of the use of the article of the present invention. Furthermore, an LED indicator may be placed at the tip of the smoking article to simulate the color change seen in a conventional cigarette when it lights up and is being smoked by a user. Other operational indicators are also encompassed. For example, visual indicators may also include changes in light color or intensity to indicate the progression of the smoking experience. Tactile and audible indicators are also encompassed by the present invention. Furthermore, combinations of such indicators may also be used in a single article.

[0097] In certain embodiments, smoking articles of the present invention may comprise tobacco, tobacco components, or tobacco-derived substances (i.e., substances naturally found in tobacco, which may be isolated directly from tobacco or synthetically prepared). The tobaccos used may include or be derived from tobaccos such as flue-cured, burley, Oriental, Maryland, dark, dark-fired, and rustica tobaccos, as well as other rare or specialty tobaccos, or blends thereof. Various representative tobacco types, tobacco process types, and tobacco blend types are described in U.S. Patent No. 4,836,224 to Lawson et al.; U.S. Patent No. 4,924,888 to Perfetti et al.; U.S. Patent No. 5,056,537 to Brown et al.; U.S. Patent No. 5,159,942 to Brinkley et al.; U.S. Patent No. 5,220,930 to Gentry; U.S. Patent No. 5,360,023 to Blakley et al.; U.S. Patent No. 6,701,936 to Shafer et al.; U.S. Patent No. 6,701,936 to Dominguez et al. No. 6,730,832 to Li et al., U.S. Pat. No. 7,011,096 to Li et al., U.S. Pat. No. 7,017,585 to Li et al., U.S. Pat. No. 7,025,066 to Lawson et al., U.S. Patent Application Publication No. 2004 / 0255965 to Perfetti et al., International Publication No. WO 02 / 37990 to Bereman, and Bombick et al., Fund. Appl. Toxicol., 39, pp. 11-17 (1997), the disclosures of which are incorporated herein by reference in their entireties.

[0098] The tobacco incorporated into the smoking article may be used in various forms. A combination of various forms of tobacco may be used, or different forms of tobacco may be used at different positions within the smoking article. For example, tobacco may be used in the form of tobacco extract. See, for example, U.S. Patent No. 7,647,932 to Cantrell et al. and U.S. Patent Application Publication No. 2007 / 0215167 to Crooks et al. (the disclosures of which are incorporated herein by reference in their entirety).

[0099] Smoking articles may incorporate tobacco additives of the type traditionally used in the manufacture of tobacco products. These additives may include materials of the type used to enhance the flavor and aroma of tobacco used to produce cigars, cigarettes, pipes, and the like. For example, such additives may include various cigarette wrap and / or top layer components. See, e.g., U.S. Pat. No. 3,419,015 to Wochnowski; U.S. Pat. No. 4,054,145 to Berndt et al.; U.S. Pat. No. 4,887,619 to Burcham, Jr. et al.; U.S. Pat. No. 5,022,416 to Watson; U.S. Pat. No. 5,103,842 to Strang et al.; and U.S. Pat. No. 5,711,320 to Martin (the disclosures of which are incorporated herein by reference in their entireties). Preferred shell materials include water, sugars and syrups (e.g., sucrose, glucose, and high fructose corn syrup), humectants (e.g., glycerin or propylene glycol), and flavorings (e.g., cocoa and licorice). These added ingredients also include top layer materials (e.g., flavorings, such as menthol). See, for example, U.S. Pat. No. 4,449,541 to Mays et al., the disclosure of which is incorporated herein by reference in its entirety. Additional materials that may be added include those disclosed in U.S. Pat. No. 4,830,028 to Lawson et al. and U.S. Patent Application Publication No. 2008 / 0245377 to Marshall et al., the disclosures of which are incorporated herein by reference in their entireties.

[0100] Various modes and methods for incorporating tobacco into smoking articles, particularly smoking articles that are designed to intentionally not combust substantially all of the tobacco within those smoking articles, are set forth in U.S. Pat. No. 4,947,874 to Brooks et al.; U.S. Pat. No. 7,647,932 to Cantrell et al.; U.S. Patent Application Publication No. 2005 / 0016549 to Banerjee et al.; and U.S. Patent Application Publication No. 2007 / 0215167 to Crooks et al., the disclosures of which are incorporated herein by reference in their entireties.

[0101] Additional tobacco materials, such as tobacco aroma oils, tobacco essences, spray-dried tobacco extracts, freeze-dried tobacco extracts, tobacco dust, etc., may be included in the vapor precursor or aerosol precursor composition. As used herein, the term "tobacco extract" refers to components separated from, removed from, or derived from tobacco using tobacco extraction processing conditions and techniques. Specifically, purified extracts of tobacco or other plants may be used. Typically, tobacco extracts are obtained using solvents such as aqueous solvents (e.g., water) or organic solvents (e.g., alcohols such as ethanol, or alkanes such as hexane). Thus, extracted tobacco components are removed from tobacco and separated from unextracted tobacco components; and for extracted tobacco components present in the solvent, (i) the solvent may be removed from the extracted tobacco components, or (ii) a mixture of the extracted tobacco components and the solvent may be used as such.Exemplary types of tobacco extracts, tobacco extractants, solvents, tobacco extract processing conditions and techniques, and tobacco extract collection and isolation procedures are disclosed in Australian Patent No. 276,250 to Schachner; U.S. Patent No. 2,805,669 to Meriro; U.S. Patent No. 3,316,919 to Green et al.; U.S. Patent No. 3,398,754 to Tughan; U.S. Patent No. 3,424,171 to Rooker; U.S. Patent No. 3,476,118 to Luttich; U.S. Patent No. 4,150,677 to Osborne; U.S. Patent No. 4,131,117 to Kite; U.S. Patent No. 4,506,682 to Muller; U.S. Patent No. 4,986,286 to Roberts et al.; U.S. Patent No. 5,005,593 to Fagg; U.S. Patent No. 5,065,596 to Fagg. ,775; U.S. Patent No. 5,060,669 to White et al.; U.S. Patent No. 5,074,319 to White et al.; U.S. Patent No. 5,099,862 to White et al.; U.S. Patent No. 5,121,757 to White et al.; U.S. Patent No. 5,131,415 to Munoz et al.; U.S. Patent No. 5,230,354 to Smith et al.; U.S. Patent No. 5,235,992 to Sensabaugh; U.S. Patent No. 5,243,999 to Smith; U.S. Patent No. 5,301,694 to Raymond; U.S. Patent No. 5,318,050 to Gonzalez-Parra et al.; U.S. Patent No. 5,435,325 to Clapp et al.; and U.S. Patent No. 5,445,169 to Brinkley et al. (the disclosures of which are incorporated herein by reference in their entireties).

[0102] The aerosol precursor or vapor precursor composition may contain one or more different components. For example, the aerosol precursor may contain a polyhydric alcohol (e.g., glycerin, propylene glycol, or a mixture thereof). Further representative types of aerosol precursor compositions are shown in U.S. Pat. No. 4,793,365 to Sensabaugh, Jr. et al.; U.S. Pat. No. 5,101,839 to Jakob et al.; PCT WO 98 / 57556 to Biggs et al.; and Chemical and Biological Studies on New Cigarette Prototypes that Heat Instead of Burn Tobacco, R.J. Reynolds Tobacco Company Monograph (1988), the disclosure of which is incorporated herein by reference. In some embodiments, the aerosol precursor composition may produce a visible aerosol upon application of sufficient heat thereto (and, optionally, cooling with air), which may be considered "smoke-like." In other embodiments, the aerosol precursor composition may produce an aerosol that is substantially invisible but whose presence may be recognized by other characteristics, such as flavor or texture. Thus, the nature of the aerosol produced may vary depending on the particular components of the aerosol precursor composition. The aerosol precursor composition may be chemically simpler than the chemistry of smoke produced by burning tobacco.

[0103] The aerosol precursor composition may contain additional liquid substances, such as water. For example, the aerosol precursor composition may incorporate a mixture of glycerin and water, or a mixture of propylene glycol and water, or a mixture of propylene glycol and glycerin, or a mixture of propylene glycol, glycerin, and water. Exemplary aerosol precursor compositions also include those incorporated into devices available from Atlanta Imports Inc., Acworth, Ga., USA, under the trade name E-CIG, which may be used with the associated smoking cartridge types C1a, C2a, C3a, C4a, C1b, C2b, C3b, and C4b; and those incorporated into devices available from Ruyan SBT Technology and Development Co., Ltd., Beijing, China, under the trade name Ruyan Atomizing Electronic Pipe and Ruyan Atomizing Electronic Cigarette.

[0104] The aerosol precursor composition used in the disclosed articles may further include one or more flavorings, medicinal agents, or other inhalable substances. For example, liquid nicotine may be used. Such additional substances may comprise one or more components of the aerosol precursor or vapor precursor composition. Thus, the aerosol precursor or vapor precursor composition may be described as comprising an inhalable substance. Such inhalable substances may include flavorings, medicinal agents, and other substances described herein. Specifically, the inhalable substance delivered using a smoking article according to the present invention may include tobacco components or tobacco-derived substances. Alternatively, the flavorings, medicinal agents, or other inhalable substances may be provided separately from the other aerosol precursor components, for example, in a reservoir. Thus, a defined amount of the flavorings, medicinal agents, or other inhalable substances may be delivered separately or simultaneously with the additional components of the aerosol precursor or vapor precursor composition to a resistive heating element to release the flavorings, medicinal agents, or other inhalable substances into the air stream inhaled by the user. Alternatively, the flavorings, medicinal agents, or other inhalable substances may be provided in a separate portion of the smoking article or its components. In certain embodiments, the flavoring, medication, or other inhalable substance may be deposited on a substrate (e.g., paper or other porous material) that is positioned close to the microheater, preferably close enough so that heating of the microheater provides sufficient heat to volatilize and release the flavoring, medication, or other inhalable substance from the substrate.

[0105] A wide variety of flavoring agents, or substances that modify the sensory or organoleptic characteristics or properties of the mainstream aerosol of a smoking article, may be used. Such flavoring agents may be obtained from sources other than tobacco, may be natural or artificial in nature, and may be used as concentrates or flavor packages. Of particular interest are flavoring agents that are applied to or incorporated into the region of the smoking article where the aerosol is generated. Again, such agents may be applied directly to the resistive heating element, as already described above, or may be provided on a substrate. Exemplary flavorings include vanillin, ethyl vanillin, cream, tea, coffee, fruit (e.g., apple, cherry, strawberry, peach, and citrus flavors including lime and lemon), maple, menthol, mint, peppermint, spearmint, wintergreen, nutmeg, clove, lavender, cardamom, ginger, honey, anise, sage, cinnamon, sandalwood, jasmine, cascarilla, cocoa, licorice, and flavors and flavor packages of the type and character traditionally used in cigarette, cigar, and pipe tobacco flavorings. Syrups, such as high fructose corn syrup, may also be used. Flavoring agents may also include acidic or basic characteristics (e.g., organic acids, such as levulinic acid, succinic acid, lactic acid, and pyruvic acid). The flavoring agents may be combined with the aerosol product as needed. Exemplary plant-derived compositions that may be used are disclosed in U.S. patent application Ser. No. 12 / 971,746 to Dube et al. and U.S. patent application Ser. No. 13 / 015,744 to Dube et al., the disclosures of which are incorporated herein by reference in their entireties.

[0106] Organic acids, in particular, may be incorporated into the aerosol precursor to affect the flavor, sensory, or organoleptic properties of a drug, such as nicotine, that may be combined with the aerosol precursor. For example, organic acids such as levulinic acid, succinic acid, lactic acid, and pyruvic acid may be included in the aerosol precursor along with nicotine in amounts up to equimolar to the nicotine (based on the total organic acid content). Any combination of organic acids may also be used. For example, the aerosol precursor may contain about 0.1 to about 0.5 moles of levulinic acid per mole of nicotine, about 0.1 to about 0.5 moles of pyruvic acid per mole of nicotine, about 0.1 to about 0.5 moles of lactic acid per mole of nicotine, or combinations thereof, in concentrations where the total amount of organic acids present is up to equimolar to the total amount of nicotine present in the aerosol precursor.

[0107] The aerosol precursor composition may take various forms based on the various amounts of materials utilized herein. For example, useful aerosol precursor compositions may contain up to about 98% by weight, up to about 95% by weight, or up to about 90% by weight of polyol. This total amount may be divided in any combination between two or more different polyols. For example, one polyol may comprise from about 50% to about 90%, from about 60% to about 90%, or from about 75% to about 90% by weight of the aerosol precursor, and a second polyol may comprise from about 2% to about 45%, from about 2% to about 25%, or from about 2% to about 10% by weight of the aerosol precursor. Useful aerosol precursors may also contain about 25%, about 20%, or about 15% by weight of water, particularly from about 2% to about 25%, about 5% to about 20%, or about 7% to about 15% by weight of water. Flavoring agents and the like (which may include agents such as nicotine) may comprise up to about 10% by weight, up to about 8% by weight, or up to about 5% by weight of the aerosol precursor.

[0108] As a non-limiting example, an aerosol precursor according to the present invention may comprise glycerol, propylene glycol, water, nicotine, and one or more flavorings. Specifically, the glycerol may be present in an amount of about 70% to about 90%, about 70% to about 85%, or about 75% to about 85% by weight, the propylene glycol may be present in an amount of about 1% to about 10%, about 1% to about 8%, or about 2% to about 6% by weight, the water may be present in an amount of about 10% to about 20%, about 10% to about 18%, or about 12% to about 16% by weight, the nicotine may be present in an amount of about 0.1% to about 5%, about 0.5% to about 4%, or about 1% to about 3% by weight, and the flavoring(s) may be present in an amount of about 5% or less, about 3% or less, or about 1% or less by weight, all amounts being based on the total weight of the aerosol precursor. One non-limiting specific example of an aerosol precursor comprises about 75% to about 80% by weight glycerol, about 13% to about 15% by weight water, about 4% to about 6% by weight propylene glycol, about 2% to about 3% by weight nicotine, and about 0.1% to about 0.5% by weight flavoring. The nicotine may be, for example, a high-nicotine tobacco extract.

[0109] The amount of aerosol precursor composition used in a smoking article is such that the article exhibits acceptable sensory and organoleptic properties and desirable performance characteristics. For example, sufficient components of the aerosol precursor composition, such as glycerin and / or propylene glycol, may be used to generate a mainstream aerosol that visually closely resembles the appearance of tobacco smoke. Typically, the amount of aerosol-forming material incorporated into a smoking article ranges from about 1.5 g or less, about 1 g or less, or about 0.5 g or less. The amount of aerosol precursor composition may depend on factors such as the desired number of puffs per cartridge used with the smoking article. It is desirable that the aerosol-forming composition not significantly induce an unacceptable taste disturbance, a thin film-like mouth sensation, or an overall sensory experience significantly different from that of traditional types of cigarettes that produce mainstream smoke by burning a tobacco cut filter. In particular, the selection of aerosol-generating and reservoir materials, the amounts of the components used, and the type of tobacco material used may be varied to control the overall chemical composition of the mainstream aerosol generated by the smoking article.

[0110] Beneficially, the microheater may be positioned in close contact with or near the aerosol precursor composition. In other embodiments, the microheater may be positioned within an article such that the aerosol precursor composition can be delivered to the microheater for aerosolization. For example, the aerosol precursor composition (or components thereof) may be provided in liquid form to allow the composition to flow from one or more reservoirs to the microheater, such as via capillary action through a wick or other porous material, or by active or passive flow (which may include valve control). Thus, the aerosol precursor composition may be provided in liquid form in one or more reservoirs positioned sufficiently far from the microheater to prevent premature aerosolization, but positioned sufficiently close to the microheater to facilitate transport of the aerosol precursor composition in a desired amount relative to the microheater for aerosolization. Alternatively, the aerosol precursor composition may be at least partially saturated within a substrate that can be in direct contact with the microheater, such that upon heating, the aerosol precursor composition is released from the substrate. Furthermore, the aerosol precursor composition may be in the form of a foam, gel, or solid. The physical state of the aerosol precursor composition may be the state of the material at ambient conditions (e.g., temperature and pressure). Such embodiments particularly allow for precise aliquots of the aerosol precursor material to be provided in contact with the microheater to achieve a defined number of puffs. Such embodiments are discussed in further detail elsewhere herein.

[0111] The amount of aerosol emitted by the articles of the present invention can vary. Preferably, the article is comprised of a sufficient amount of aerosol precursor composition, and a sufficient amount of any additional inhalable substance, to function for a sufficient time and at a sufficient temperature to emit the desired amount of aerosolized substance over the course of use. This amount may be provided in a single inhalation from the article, or may be distributed over multiple puffs from the article over a relatively short period of time (e.g., less than 30 minutes, less than 20 minutes, less than 15 minutes, less than 10 minutes, or less than 5 minutes). For example, the article may provide nicotine in an amount of about 0.01 mg to about 0.5 mg, about 0.05 mg to about 0.3 mg, or about 0.1 mg to about 0.2 mg per puff from the article. For calculation purposes, an average puff time of about 2 seconds can deliver a puff volume of about 5 ml to about 100 ml, about 15 ml to about 70 ml, about 20 ml to about 60 ml, or about 25 ml to about 50 ml. Such total puff volumes can, in certain embodiments, provide the WTPM content previously described. Smoking articles according to the present invention can be configured to provide any number of puffs that can be calculated by dividing the total amount of aerosol or other inhalable substance delivered by the amount delivered per puff. One or more reservoirs may be filled with appropriate amounts of aerosol precursor or other inhalable substance to achieve the desired number of puffs and / or the desired total amount of substance delivered.

[0112] In further embodiments, heating can be characterized in terms of the amount of aerosol to be generated. Specifically, the article can be configured to provide the amount of heat necessary to generate a specified volume of aerosol (e.g., about 5 ml to about 100 ml, or any other volume deemed useful in a smoking article, such as those described elsewhere herein). In certain embodiments, the amount of heat generated can be measured for a 2-4 second puff, with a heater temperature of about 290°C providing about 35 ml of aerosol. In some embodiments, the article can preferably provide about 1 to about 50 joules per second (J / s), about 2 J / s to about 40 J / s, about 3 J / s to about 35 J / s, or about 5 J / s to about 30 J / s of heat.

[0113] The microheater may preferably be electrically connected to a power source of the smoking article such that electrical energy is provided to the microheater to generate heat and subsequently aerosolize the aerosol precursor composition and its various components. Such electrical connection may be permanent (e.g., hardwired) or removable (e.g., where the microheater is provided in a cartridge that is detachable from a control body that includes a power source).

[0114] While various materials for use in smoking articles according to the present invention have been described above (e.g., heaters, batteries, capacitors, switching components, reservoirs, dispensers, aerosol precursors, etc.), the present invention should not be construed as being limited solely to the illustrated embodiments. Those skilled in the art will recognize, based on this disclosure, similar components in the art that may be interchangeable with any particular component of the present invention.For example, U.S. Patent No. 5,261,424 to Sprinkel, Jr. discloses a piezoelectric sensor that may be associated with the mouth end of the device that detects the movement of the user's lips associated with taking a puff and then induces heating; U.S. Patent No. 5,372,148 to McCafferty et al. discloses a puff sensor for controlling energy flow to a heat load array in response to a pressure drop through a mouthpiece; U.S. Patent No. 5,967,148 to Harris et al. discloses a receptacle in a smoking device with an identifier that detects non-uniformity in the infrared transmittance of inserted components and a control device that performs a detection operation as the component is inserted into the receptacle; U.S. Patent No. 6,040,560 to Fleischhauer et al. describes a defined, viable power cycle with a number of different stages; U.S. Patent No. 5,934,289 to Watkins et al. discloses a photonic-optronic U.S. Patent No. 5,954,979 to Counts et al. discloses means for varying the resistance to draw by a smoking device; U.S. Patent No. 6,803,545 to Blake et al. discloses particular battery configurations for use in smoking devices; U.S. Patent No. 7,293,565 to Griffen et al. discloses various charging systems for use in smoking devices; U.S. Patent Application Publication No. 2009 / 0320863 to Fernando et al. discloses computer interface means for a smoking device that facilitates charging and allows computer control of the device; U.S. Patent Application Publication No. 2010 / 0163063 to Fernando et al. discloses particular systems for smoking devices; and WO 2010 / 003480 to Flick discloses a flow detection system that is an indicator of puffs in an aerosol generating system; all of the foregoing disclosures are incorporated herein by reference in their entireties.Further examples of components related to electronic aerosol delivery articles and disclosed materials or components that may be used in the articles of the present invention include U.S. Pat. No. 4,735,217 to Gerth et al.; U.S. Pat. No. 5,249,586 to Morgan et al.; U.S. Pat. No. 5,666,977 to Higgins et al.; U.S. Pat. No. 6,053,176 to Adams et al.; U.S. Pat. No. 6,164,287 to White; U.S. Pat. No. 6,196,218 to Voges; U.S. Pat. No. 6,810,883 to Felter et al.; U.S. Pat. No. 6,854,461 to Nichols; U.S. Pat. No. 7,832,410 to Hon; U.S. Pat. No. 7,513,222 to Kobayashi; No. 53; U.S. Patent No. 7,896,006 to Hamano; U.S. Patent No. 6,772,756 to Shayan; U.S. Patent Application Publication Nos. 2009 / 0095311, 2006 / 0196518, 2009 / 0126745, and 2009 / 0188490 to Hon; U.S. Patent Application Publication Nos. 2009 / 0272379 to Thorens et al.; U.S. Patent Application Publication Nos. 2009 / 0260641 and 2009 / 0260642 to Monsees et al.; U.S. Patent Application Publication Nos. 2008 / 0149118 and 2010 / 0024834 to Oglesby et al.; U.S. Patent Application Publication No. 2010 / 0307518 to Wang; and WO 2010 / 0307518 to Hon 2010 / 091593, the disclosures of which are all incorporated herein by reference in their entirety.

[0115] Although the article of the present invention may take on various embodiments, as discussed in detail below, the use of the article by a consumer remains similar in scope. Specifically, the article may be provided as a single unit or as multiple components that are assembled by the consumer for use and then disassembled by the consumer. Generally, a smoking article of the present invention may include a first unit engageable and releasable with a second unit, the first unit including a resistive heating element, and the second unit including a power source. In some embodiments, the second unit may further include one or more control components for activating or regulating current from the power source. The first unit may include a distal end that mates with the second unit and an opposing proximal end including a mouthpiece (or simply a mouth end) that opens at the proximal end. The first unit may include an airflow path opening to the mouthpiece of the first unit, which may provide for the passage of aerosol formed from the resistive heating element to the mouthpiece. In a preferred embodiment, the first unit may be disposable. Similarly, the second unit may be reusable.

[0116] A smoking article according to the present invention may have a reusable control body that is substantially cylindrical in shape, having a connecting end and an opposing closed end. The closed end of the control housing may include one or more indicators of active use of the article. The article may include a cartridge having a connecting end that engages the connecting end of the control body and an opposing mouth end. During use, a consumer may connect the connecting end of the cartridge to the connecting end of the control body or otherwise combine the cartridge and control body, thereby enabling the article to be operated as discussed herein. In some embodiments, the connecting ends of the control body and cartridge may be attached by a threaded engagement. In other embodiments, the connecting ends may have a press-fit engagement.

[0117] During use, a consumer initiates heating of the resistive heating element, and heat generated by the resistive heating element aerosolizes the aerosol precursor composition, and optionally, additional inhalable substances. Such heating releases at least a portion of the aerosol precursor composition in the form of an aerosol (which may include any additional inhalable substances contained therein), and such aerosol is provided within an interior space of the cartridge that is in liquid communication with the mouth end of the cartridge. When a consumer inhales into the mouth end of the cartridge, air is drawn through the cartridge, and the combination of drawn air and aerosol is inhaled by the consumer as the drawn substance exits the mouth end of the cartridge (or any mouthpiece present) toward the consumer's mouth. To initiate heating, the consumer may activate a push button, capacitance sensor, or similar component, causing the resistive heating element to receive electrical energy from a battery or other energy source (e.g., a capacitor). This electrical energy may be supplied for a predetermined length of time or may be manually controlled. Preferably, the flow of electrical energy does not substantially progress during a puff on the article (although energy flow may progress to maintain a baseline temperature above ambient temperature—e.g., a temperature that facilitates rapid heating to an active heating temperature). In further embodiments, heating may be initiated by the consumer's puffing action through the use of various sensors, as described elsewhere herein. Once a puff is interrupted, heating is stopped or reduced. When the consumer has taken a sufficient number of puffs, thereby releasing a sufficient amount of inhalable substance (e.g., an amount sufficient to equate to a typical smoking experience), the cartridge may be removed from the control housing and discarded. An indication may be provided that the cartridge is consumed (i.e., the aerosol precursor composition has been substantially consumed by the consumer). In some embodiments, a single cartridge may provide two or more smoking experiences, thereby providing a sufficient amount of aerosol precursor composition to simulate a full pack of conventional cigarettes or more.

[0118] The foregoing description of the use of this article can be applied to the various embodiments described with minor modifications that may be apparent to those skilled in the art in light of the further disclosure provided herein. However, the above description of the use is not intended to limit the use of the article of the present invention, but is presented to meet all essential requirements of the present disclosure.

[0119] Referring now to FIG. 2, a smoking article 10 according to the present invention may generally comprise a shell 15 and multiple components disposed within the shell. The article may be characterized as having a mouth end 11 (i.e., the end at which a consumer can inhale aerosol from the article) and a tip end 12. The illustrated article is provided as a single unitary device (although line A indicates an optional boundary by which the device may be separated into two separate components, which may be removably or permanently attached together, such as by adhesive). As will become apparent from the further disclosure herein, for further embodiments of the article, it may be preferable to form the article from two or more connectable units, each housing another component of the article. The various components shown in the embodiment of FIG. 2 may be present in other embodiments, including embodiments formed from multiple units.

[0120] Article 10 can have an overall shape that can be defined as being substantially rod-shaped, or substantially tubular-shaped, or substantially cylindrical-shaped. As shown in Figure 2, the article has a substantially round cross-section; however, other cross-sectional shapes (e.g., oval, square, triangular, etc.) are encompassed by this disclosure. Such language, which is indicative of the article's physical shape, may also apply to individual units of the article in embodiments comprising multiple units, such as a control body and a cartridge.

[0121] The shell 15 of the smoking article 10 may be formed from any material suitable for forming and maintaining a suitable higher-order structure, such as a tubular shape, and for retaining the appropriate components of the article therein. The shell may be formed from a single wall, as shown in FIG. 2. In some embodiments, the shell may be formed from a material (natural or synthetic) that is heat-resistant and thereby maintains its structural integrity (e.g., does not decompose at temperatures at least as high as those provided by a resistive heating element, as discussed further below). In some embodiments, a heat-resistant polymer or metal (e.g., stainless steel) may be used. In other embodiments, the shell may be formed from paper, e.g., substantially straw-shaped paper. A shell, such as a paper tube, may have one or more layers associated therewith that function to substantially impede the movement of vapor therethrough. In one example, a layer of aluminum foil may be laminated to one side of the shell. Ceramic materials may also be used.

[0122] In further embodiments, smoking articles according to the present invention may include various materials that can provide specific functions. For example, the shell 15 may include an overwrap over at least a portion thereof, such as at the mouth end of the article, and such an overwrap may also be formed from multiple layers. This overwrap may be, for example, a typical cigarette wrapper. This overwrap may particularly include a material typically used in the filter elements of conventional cigarettes, such as cellulose acetate, which may function to provide the consumer with the sensation of a conventional cigarette in their mouth. Exemplary types of packaging materials, packaging material components, and treated packaging materials that may be used in the overwraps of the present invention are described in U.S. Pat. No. 5,105,838 to White et al.; U.S. Pat. No. 5,271,419 to Arzonico et al.; U.S. Pat. No. 5,220,930 to Gentry; U.S. Pat. No. 6,908,874 to Woodhead et al.; U.S. Pat. No. 6,929,013 to Ashcraft et al.; U.S. Pat. No. 7,195,019 to Hancock et al.; U.S. Pat. No. 7,276,120 to Holmes; U.S. Pat. No. 7,275,548 to Hancock et al.; PCT WO 01 / 08514 to Fournier et al.; and PCT WO 03 / 043450 to Hajaligol et al., the disclosures of which are incorporated herein by reference in their entireties. Representative packaging materials are commercially available from Schweitzer-Maudit International as RJ Reynolds Tobacco Company grades 119, 170, 419, 453, 454, 456, 465, 466, 490, 525, 535, 557, 652, 664, 672, 676 and 680.

[0123] One or more layers of non-porous cigarette paper may be used to encase the article (with or without an overwrap). Examples of suitable non-porous cigarette paper are commercially available from Kimberly-Clark Corp. as KC-63-5, P878-5, P878-16-2, and 780-63-5. The overwrap (or shell, if no overwrap is present) may comprise a resilient paperboard material, foil-lined paperboard, metal, polymeric material, foam, nanofiber web, etc., which may be constrained by the cigarette paper wrap. The article may also include tipping paper that constrains the article and may be used to bond a filter material to the article, if desired.

[0124] As can be seen from the embodiment of FIG. 2 , the smoking article 10 includes an electronic control component 20, a flow sensor 30, and a battery 40, which may be arranged in various orders within the article. While not explicitly shown, it is understood that the article 10 may include wiring necessary to provide power from the battery 40 to additional components and to interconnect the components for proper operation of the necessary functions provided by the article. The article 10 may further include a micro-heater 50 as described herein. The micro-heater may be electrically connected to the battery 40 through appropriate wiring that facilitates the formation of a closed electrical circuit by current flowing through the micro-heater. Additional wiring (not shown) may be included to achieve the necessary electrical connections within the article. In certain embodiments, the article 10 may be electrically wired such that the control component 20 delivers, controls, or otherwise adjusts power from the battery 40 to energize the micro-heater 50 according to one or more predetermined algorithms, including pulse width modulation, as already described above. Such electrical circuitry may specifically incorporate a flow sensor 30 so that the article 10 is only active at the time of use by the consumer. For example, if a consumer puffs on the article 10, the flow sensor detects the puff, which then activates the control component 20, directing power through the article, causing the microheater 50 to generate heat, thereby providing an aerosol for inhalation by the consumer. The control algorithm may then direct the microheater 50 to provide power to the circuit, thereby maintaining a predetermined temperature. Accordingly, the control algorithm may be programmed to automatically shut off the article 10 and cut off the flow of power through the article after a predetermined time delay in the absence of a puff by the consumer. Additionally, the article may include a temperature sensor to provide feedback to the control component. Such a sensor may, for example, be in direct contact with the microheater 50. Alternative temperature sensing means may be used as well, such as relying on a logic control component to increase resistance through a resistive heating element and correlate such resistance with the temperature of the element.In other embodiments, the flow sensor 30 may be replaced by suitable components to provide alternative sensing means, such as capacitive sensing, as described elsewhere herein. Any of a variety of sensors and combinations thereof may be incorporated as previously described herein. Still further, the article 10 may include one or more control buttons 16 that allow manual actuation by a consumer to trigger various functions, such as turning power on and off, turning on the microheater 50 to generate vapor or aerosol for inhalation, etc.

[0125] Additionally, the article may include one or more status indicators 19 disposed on the shell 15. Such indicators, as described above, may indicate the number of puffs taken or remaining on the article, may be indicators of an active or dormant state, may illuminate in response to a puff, etc. Although six indicators are illustrated, there may be more or fewer indicators, which may be of different shapes and orientations, or may even simply be openings in the shell (e.g., for the emission of sound, if such indicators are present).

[0126] As shown in the embodiment of FIG. 2, a reservoir 205, illustrated as a container, is shown proximate to the microheater 50, and a transfer element 300 extends from the reservoir 205 and sufficiently proximate to the microheater so that the aerosol precursor composition can be delivered to the microheater for aerosolization. The formed aerosol is then drawn by a user through the mouth end 11 of the smoking article 10. The aerosol precursor composition aerosolized by the heating of the microheater may be continuously replenished (e.g., through a wick or other flow of the aerosol precursor composition from the reservoir to the microheater via the transfer element), or specific aliquots of the aerosol precursor composition may be delivered to the microheater on demand. This cycle continues until substantially all of the aerosol precursor composition has been aerosolized.

[0127] As can be seen in the embodiment of FIG. 2, the mouth end 11 of the article 10 is a substantially open cavity within which the microheater 50 and reservoir 205 are disposed. Such an open cavity provides a volume for the release of the aerosol formed by the microheater. The article also includes a mouth opening 18 in the mouth end 11 to allow for the withdrawal of the aerosol from the cavity. Although not explicitly shown in FIG. 2, the article may include a filter material (e.g., cellulose acetate or polypropylene) at the mouth end to enhance its structural integrity and / or provide optional filtration and / or create resistance to inhalation. For example, an article according to the present invention may exhibit a water pressure drop of about 50 to 250 mm at a 17.5 cc per second airflow. In further embodiments, the pressure drop may be about 60 mm to about 180 mm, or about 70 mm to about 150 mm. Pressure drop values ​​may be measured using a Filtrona Filter Test Station (CTS Series) available from Filtrona Instruments and Automation Ltd or a Quality Test Module (QTM) available from Cerulean Division of Molins, PLC. To facilitate air flow through the article, an air intake 17 may be provided, which may essentially comprise an opening in shell 15 that allows air to flow into the interior of the article. Multiple air intakes may be provided, and an air intake may be located anywhere upstream from the mouth end of the article so that air from the air intake interacts with the formed aerosol to facilitate its removal from the cavity of the article and through the opening in the mouth end.

[0128] In other embodiments, the reservoir may be a substrate adapted to hold the aerosol precursor composition, e.g., a layer of material at least partially saturated with the aerosol precursor composition. Such a layer may be absorbent, adsorbent, or otherwise porous, thereby providing the ability to hold the aerosol precursor composition. Thus, the aerosol precursor composition may be characterized as coated on, adsorbed to, or absorbed within a carrier material (or substrate), which may form all or part of the substrate material, which may also support one or more microheaters. The carrier material may be disposed within the article so as to be in substantial contact with one or more microheaters (i.e., multiple microheaters).

[0129] 2, reservoir 205 may be a container formed of one or more walls defining an interior volume in which the aerosol precursor composition, or one or more components thereof, is stored. The container may be formed of substantially rigid walls, and movement of aerosol precursor material therefrom may proceed by active or passive movement methods as discussed herein. Alternatively, the container may be formed of a substantially plastic material such that the container can be compressed (i.e., an airbag reservoir) to facilitate movement of aerosol precursor material therefrom.

[0130] In preferred embodiments, the article may have a size comparable to the shape of a cigarette or cigar. Thus, the article may have a diameter of about 5 mm to about 25 mm, about 5 mm to about 20 mm, about 6 mm to about 15 mm, or about 6 mm to about 10 mm. Such dimensions may particularly correspond to the outer diameter of the shell.

[0131] The smoking article 10 of the embodiment illustrated in FIG. 2 may be characterized as a disposable article. Accordingly, for the reservoir containing the aerosol precursor composition in such an embodiment, it may be desirable to include a sufficient amount of aerosol precursor composition to allow a consumer to use the article more than once. For example, the article may include sufficient aerosolizable and / or inhalable material so that the article can provide a number of puffs (of about 2-4 seconds duration) substantially equivalent to the number of puffs possible from a plurality of conventional cigarettes (e.g., 2 or more, 5 or more, 10 or more, or 20 or more conventional cigarettes). More specifically, a disposable, single-unit article according to the embodiment of FIG. 2 may provide about 20 or more, about 50 or more, or about 100 or more puffs (where a puff is measured as previously described herein).

[0132] In some embodiments, the articles described herein may comprise two units that are detachable from one another. For example, FIG. 3 illustrates a smoking article 10 according to one embodiment, formed from a control body 80 and a cartridge 90. In certain embodiments, the control body may be reusable, and the cartridge may be disposable. In some embodiments, the entire article may be characterized as disposable in that the control body may be configured for a limited number of uses with a limited number of cartridges, after which the entire article 10, including the control body, may be discarded (e.g., until the battery power component no longer provides sufficient power to the article). In other words, the control body may have a replaceable battery, such that the control body may be reused with multiple battery changes and with many cartridges. The article 10 may be rechargeable and thus may be combined with any type of recharging technology, such as connection to a regular electrical outlet, a car charger (i.e., a cigarette lighter outlet), or a computer via a USB cable, for example.

[0133] The control body 80 and cartridge 90 are specially configured to engage with each other to form an interconnected, functional device. As shown in FIG. 3 , the control body 80 includes a proximal mating end 13 that includes a protrusion 82 of reduced diameter relative to the control body. The cartridge includes a distal mating end 14 that engages the proximal mating end of the control body 80 to place the smoking article 10 in a functional, usable form. In FIG. 3 , the control body protrusion 82 includes a thread that allows the cartridge 90 to be threaded onto the control body 80 via corresponding threads (not visible in FIG. 3 ) on the distal mating end of the cartridge. Accordingly, the distal mating end of the cartridge 90 may include an open cavity for receiving the control body protrusion 82. While a threaded engagement is illustrated in FIG. 3 , it is understood that additional means of engagement are encompassed, such as a press-fit engagement, a magnetic engagement, and the like.

[0134] The placement of the micro-heaters within the article may vary. In certain embodiments, one or more micro-heaters may be coupled to a substrate, which may be permanently incorporated into or removable from the smoking article. Examples of such embodiments are shown in FIGS. 4 and 5. Referring first to FIG. 4, a substrate 600 is shown having a plurality of micro-heaters 50 mounted thereon. The micro-heaters may be characterized as being mounted to the surface of the substrate, embedded within the substrate, or housed within the substrate (e.g., in wells or other depressions formed in the substrate, as described elsewhere below). The substrate may be formed from any material suitable for use in a smoking article and preferably comprises an electrically insulating material. Substrate materials include, but are not limited to, polymeric materials, particularly heat-resistant polymers, paper, cardboard, ceramics, and the like. While five micro-heaters are shown in the illustrated embodiment, it is understood that, given the relatively small size of the micro-heaters, more or fewer micro-heaters may be utilized on a single substrate. Additionally, multiple substrates may be used, each substrate having one or more micro-heaters thereon. Although not explicitly shown, it is understood that the substrate may include any electrical wiring useful for forming the electrical connection necessary for the micro-heater to be powered from a power source. Similarly, the substrate may include electrical contacts useful for forming electrical connections with plugs or other electrical components of the article. For example, each individual micro-heater may be wired to a common electrical contact on the substrate.

[0135] The aerosol precursor composition (or one or more components thereof) may be stored in a reservoir present in or on the substrate 600. For example, the perimeter of the substrate may include one or more containers, porous materials, etc. (useful for storing one or more components of the aerosol precursor therein), and one or more transport elements may be present to transport the aerosol precursor composition from the reservoir to the microheater. The microheater, reservoir, and transport element may be characterized as being self-contained on a single substrate or on the same substrate. In other embodiments, a transport element may not be present.

[0136] More specifically, FIG. 5 illustrates one embodiment of a closed device as viewed as a cross-sectional view of the substrate along line AA in FIG. 4 . In this embodiment, the microheaters 50 are recessed a distance within the substrate 600. The substrate may therefore be described as comprising one or more heater wells 610. Individual microheaters may then be placed within the heater wells, and all or a portion of the remaining well volume may be filled with the aerosol precursor composition 700 (or components thereof). The depth of the wells may vary depending on the volume of aerosol precursor material used. In such embodiments, the aerosol precursor composition may be beneficially provided in a form that prevents the aerosol precursor composition from significantly escaping the heater wells 610, such as a gel or foam, or other solid or semi-solid form. The gel or (another form of aerosol precursor) may be coated onto the microheater. The microheater may therefore be characterized as operably disposed within the smoking article in substantial contact with the aerosol precursor composition. This description is applicable to additional arrangements of aerosol precursor compositions and microheaters, as described elsewhere herein.

[0137] As shown in FIG. 5, the heater well containing the microheater and the aerosol precursor material disposed therein is present on only one side of the substrate. In other embodiments, the well may be present on both sides of the substrate. Additionally, other substrate configurations are encompassed, such as three-sided (e.g., having a triangular cross-section), four-sided (e.g., having a square, rectangular, trapezoidal, or other similar cross-section), or multi-arm cross-sections (e.g., three-armed, four-armed, or more). Such configurations may provide sufficient surface area to accommodate a relatively large number of microheaters on a single substrate. For example, a substrate having a four-arm cross-section (e.g., a cross-shaped) may have up to eight surfaces available for placement of microheaters. In other embodiments, the substrate may be in the form of a cylinder, and the microheaters may be distributed circumferentially on one or both of the inner and outer surfaces of the cylindrically shaped substrate.

[0138] Providing a relatively large number of microheaters can be particularly beneficial when it is desirable to separately heat two or more components of an aerosol precursor composition. Specifically, see FIG. 5 . One heater well 610 may contain one component of the precursor composition (e.g., a polyol), while another heater well may contain a different component, such as a flavor or a pharmaceutical. Accordingly, the device may include a controller adapted to activate microheaters corresponding to different components of the aerosol precursor composition according to different algorithms. For example, different microheaters may heat to different temperatures, for different lengths of time, or in a particular sequence. Furthermore, certain microheaters may be automatically activated by a control component in response to activation of the device (e.g., upon activation of a pressure sensor indicating inhalation on the device), while other microheaters may be manually controlled (e.g., by a push button). For example, one or more microheaters may be adapted to heat a particular flavor (e.g., menthol), and the user of the device may use manual control to deliver only the flavor as desired. As can be seen from the foregoing, the use of multiple microheaters allows for greater customization of the heating profile of the device and greater customization of the aerosol composition delivered with each puff on the device.

[0139] Still further configurations of microheaters in or on a substrate are encompassed by the present disclosure. For example, multiple microheaters may be combined with a substrate to provide a bank of heaters. As shown in the embodiment of FIG. 6, a bank of microheaters 50 may be provided in a substrate. In this embodiment, a substrate 600 includes a first layer 603 and a second layer 605, and the microheater may be sandwiched between the two layers. One of the first and second layers may include a porous material that can function as a reservoir for the aerosol precursor composition (or one or more components thereof), which may be stored across substantially the entire area of ​​the layer or deposited only in one or more specific areas corresponding to one or more microheaters. Thus, an individual microheater may be activated to aerosolize the entire aerosol precursor composition in a region proximate the microheater. Alternatively, an individual microheater may be activated to aerosolize specific components of the aerosol precursor composition in a region proximate the microheater.

[0140] In further embodiments, a substrate containing an aerosol precursor composition (or one or more components thereof) may be provided, and one or more microheaters may be provided integrally with the devices described herein. More specifically, the microheaters may be disposed internally to a smoking article as discussed herein, and the substrate containing the aerosol precursor composition may be disposed within the article, such that the substrate is in substantial contact with the bank of microheaters or a single microheater. The substrate may be replaceable as needed, such that an article containing a bank of microheaters can be reused by simply discarding the depleted substrate and inserting a fresh substrate with the aerosol precursor composition thereon into the article. One such embodiment is illustrated in FIG. 7.

[0141] As can be seen in FIG. 7 , an embodiment of an electronic smoking article 10 is illustrated, essentially a single, continuous body 150 having a hinged door 101. In the open position, the door reveals an aerosolization cavity lined with an array of micro-heaters 50. In the illustrated embodiment, the micro-heaters are disposed on the interior surface of the hinged door 101 and on the inner surface of the article. To use the article, a substrate 600 containing an aerosol precursor composition is placed within the aerosolization cavity of the article. A substantially flat substrate is then placed within the cavity such that the top and bottom surfaces of the substrate 600 are each in substantial contact with the array of micro-heaters, and the hinged door 101 is closed. After use of the article substantially depletes the substrate of aerosol precursor composition, the hinged door may be opened, the substrate removed, and replaced with a new substrate containing the aerosol precursor composition. In other embodiments, the micro-heaters may be disposed only on the interior surface of the hinged door or only on the interior surface of the aerosolization cavity. The array of micro-heaters may be configured to heat the substrate according to any desired algorithm, as previously described herein.

[0142] In some embodiments, the micro-heaters may be characterized as being arranged in a series. Alternatively, the micro-heaters may be provided in one or more different spatial arrangements. The particular arrangement of the micro-heaters may be predefined to heat specific locations on the substrate in a particular order and / or to simultaneously heat two or more different portions of the substrate at the same time. Thus, the combination of multiple micro-heaters in the disclosed devices may be characterized as an array of heaters.

[0143] While the substrate 600 in FIG. 7 is depicted as a generally flat rectangle, other shapes, such as a cylinder, are possible. In other embodiments, the substrate may be a substantially elongated member having a defined cross-section, e.g., square, round, triangular, etc., and the dimensions of the substrate may vary as needed to substantially contact one or more microheaters as long as the substrate is sized to fit within the aerosolization cavity within the article. Furthermore, the number of microheaters lining the aerosolization cavity may vary. Similarly, as the shape and dimensions of the substrate are varied, the shape and dimensions of the aerosolization cavity within the article may vary accordingly, and the aerosolization cavity may be substantially the same shape and size as the substrate. In yet other embodiments, a hinged door 101 may be positioned along any of the article 10 to facilitate access to the aerosolization cavity. For example, the mouth end 11 of the article may be a hinged door such that the entire mouth end of the article hinges open to provide access to the aerosolization cavity for placement and removal of the substrate 600. For example, such a structure may limit direct access to the microheater by a user.

[0144] In certain embodiments, the reservoir used to store the aerosol precursor composition may be a container (e.g., an airbag), and the article may be adapted to meter a predetermined amount of the aerosol precursor composition from the container. Mechanical components (e.g., a plunger and a drive mechanism, e.g., a spring) may be provided and may be electrically controlled by the microheater or similar components of the article. Micropumping devices may be particularly used. Related components may also provide an indication of the liquid fill state of the reservoir. Similarly, passive microfluidic devices may be used to transfer the aerosol precursor composition, or one or more of its components, to the microheater. Such devices are particularly useful because they do not necessarily require a separate power source, and the control exerted by the device can be based at least in part on energy extracted from the liquid being transferred or on surface effects such as surface tension, selective hydrophobic / hydrophilic control, etc. Examples of passive microfluidic devices can be found, for example, in Springer Handbook of Nanotechnology, edited by Bharat Bhushan, Section 19.3, Smart Passive Microfluidic Devices, November 29, 2006, pp. 532-540, the disclosure of which is incorporated herein by reference in its entirety.

[0145] A reservoir containing the aerosol precursor composition may be in liquid communication with a microheater as discussed herein through one or more additional components. For example, the container may be in contact with a dispenser that facilitates the movement of the liquid aerosol precursor composition out of the container and onto the microheater. The dispenser may be connected to the container through a suitable passageway, such as appropriately sized tubing or other transport element. Optionally, one or more valves may be included, in that openings of the valves (e.g., via electronic control by a microcontroller or similar component of the article) may allow the passage of the liquid aerosol precursor composition out of the reservoir or through a passageway, or out of the dispenser and onto the microheater. Such valve mechanisms may be present in addition to, or instead of, other mechanical components that actively displace the aerosol precursor composition from the container.

[0146] The dispenser may dispense the aerosol precursor composition onto the microheater (which may be on a separate substrate). In some embodiments, the dispenser may be integral with or otherwise attached to the microheater substrate, and may include various components for maintaining the aerosol precursor composition in proximity to the microheater for aerosolization thereof and for release of the formed aerosol.

[0147] The microheater may also be provided as part of a laminated substrate that can be effectively characterized as an atomizing device. For example, FIG. 8 illustrates atomizer 800, a laminated structure that forms an open cavity that overlies the microheater discussed herein. Thus, the microheater may be characterized as being integral with the atomizer. Specifically, atomizer 800 includes support layer 510, on which is disposed conductive layer 520. Protective layer 540 is shown laminated with the conductive layer. Above the protective layer is atomization chamber 810, which is an open space defined by atomization chamber walls 820, chamber cover 830, and the microheater (particularly the microheater's protective layer). The chamber cover and protective layer are shown as partially transparent for ease of illustration, although opaque or translucent materials may be used as well. A plurality of openings 840 are provided in the atomization chamber walls to allow the vaporized aerosol precursor material to pass out of the atomizer. Preferably, the openings are sized to allow vapor to pass through them but not the liquid aerosol precursor composition. A liquid passage 850 connects the atomizer to the reservoir and opens into the atomization chamber, allowing liquid precursor material to enter the chamber for evaporation. This liquid passage may be tubing having a diameter of about 250 μm to about 1,000 μm, about 300 μm to about 750 μm, or about 400 μm to about 600 μm. As discussed herein, the passage of liquid may occur via active or passive means. If passive means are used, the liquid passes freely into the chamber, where it awaits vaporization, but does not exit through opening 840. When the heater is activated, the liquid is vaporized and exits the chamber through the opening, allowing the chamber to be backfilled by the ingress of additional liquid precursor material. The atomization chamber is preferably sized so that substantially all of the liquid present in the chamber is completely vaporized in one go for removal therefrom. If desired, means may be provided to prevent the passage of formed vapor from the atomization chamber to the liquid passage. For example, a ball valve (not shown) may be provided at the opening of the liquid passage to the atomizing chamber.The layers of the atomizer may be attached together such as by a eutectic metallurgical bond.

[0148] Terminals 530 extending from the conductive layer 520 electrically connect the microheater (particularly the conductive material) to additional electrical components of the article. The chamber walls and chamber cover can be formed from any suitable material that is heat resistant and chemically non-reactive with the aerosol precursor composition. For example, the chamber walls may be formed from silicon and the chamber cover may be formed from glass, although other materials discussed herein, for example, for use as support and / or protective layers, may also be used to form the chamber walls and chamber cover independently.

[0149] While the structures discussed above may be particularly beneficial, they are not required; rather, the above components may be combined in various ways. For example, an atomizer may be formed such that a microheater is thermally coupled to an atomization chamber formed from one or more walls. The chamber may be adapted to receive a predetermined amount of aerosol precursor composition, such as through an opening in the chamber wall. The walls defining the chamber (including, as applicable, the cover) preferably include one or more openings adapted for the exit of vapor or aerosol from the chamber and for the entry of air into the chamber. In certain embodiments, the opening adapted for the exit of vapor or aerosol may also be used for the entry of air into the chamber.

[0150] The exemplary embodiment illustrated in FIG. 9 shows a sprayer 800 comprising a support layer 510, atomization chamber walls 820, and a sprayer chamber cover 830. The atomization chamber, conductive layer, and protective layer are not visible in this view. In this embodiment, cover 830 comprises a plurality of cover openings 845, and the chamber walls are continuous along the circumferential length of the sprayer. A liquid passage 850 connects the sprayer to a reservoir and opens into the atomization chamber to allow liquid precursor material to pass to the vaporization chamber. In this embodiment, the cover may be formed from a metal mesh, and the cover openings are sized to allow vaporized aerosol precursor composition to pass therethrough but not liquid aerosol precursor composition. Alternatively, the cover may be formed from other suitable materials, such as ceramic, high-temperature polymer, silicon, glass, etc. The sprayer cover and sprayer chamber walls may be advantageously formed as a unitary structure, such as by using suitable photolithography techniques. Specifically, a cover may be bonded to a blank of the material used for the atomization chamber walls, and etching may be used to remove the material necessary to form the walls, leaving a chamber of the desired dimensions. The chamber walls may then be laminated to a cover that is laminated to a support layer or a conductive layer on a support layer.

[0151] Due to the size of the microheater itself, the atomizer may similarly be relatively small. For example, the atomizer may have an overall length of about 2 mm to about 12 mm, about 3 mm to about 10 mm, or about 4 mm to about 8 mm, and an overall width of about 1 mm to about 7 mm, about 1.5 mm to about 6 mm, or about 2 mm to about 5 mm. The atomizing chamber may have a volume of about 0.2 ml to about 1 ml, about 0.3 ml to about 0.9 ml, or about 0.4 ml to about 0.8 ml. One or more atomizers may be included in the article, and the atomizers may be in fluid communication with one or more reservoirs (which may contain the entire aerosol precursor composition or specific components of the aerosol precursor composition). The article may be characterized as comprising an aerosol precursor composition comprising multiple individual components, multiple reservoirs separately containing the individual components of the aerosol precursor composition, and multiple atomizers or chambers adapted to receive predetermined amounts of the individual components of the aerosol precursor composition from the reservoirs.

[0152] In particular, the atomizer described above may be incorporated into the cartridge of a smoking article as described herein. For example, the atomizer may be connected to a reservoir, such as a walled container, via a liquid passageway (e.g., stainless steel tubing). The reservoir may maintain a positive pressure on the aerosol precursor composition therein, such that the liquid aerosol precursor composition continuously fills the atomizer chamber after evaporation during use. In one embodiment, the reservoir may include a plunger biased, such as by a spring, to maintain a positive pressure on the liquid aerosol precursor composition in the reservoir. Optionally, an indicator may be attached to the plunger that moves with the plunger. Thus, the smoking article may include a window in the body through which the indicator is visible. As the liquid aerosol precursor composition is depleted, the plunger moves in a predetermined direction. Thus, the indicator also moves in the same direction. The window may be positioned so that the indicator moves through the window, providing an indication of the fill status of the liquid aerosol precursor composition. For example, color coding may be used to indicate fill status with one or more different colors appearing in the window as the liquid is depleted. Similarly, a depletion indicator may be used to indicate fill status with an indicator that moves from no depletion to full depletion as the liquid is depleted. In other embodiments, a digital screen may be provided rather than a window, and the mechanical movement of the plunger may be electronically converted into an appropriate signal to indicate fill status on the digital screen. Similarly, a series of LEDs may be used to indicate fill status.

[0153] In addition to the above, it should be noted that various reservoirs may be utilized for the various embodiments described above. For example, the reservoir may be a container, such as a bottle, in which the aerosol precursor composition is stored. The container may be substantially impermeable to the aerosol precursor so that the material cannot escape through the container walls. In such embodiments, an opening may be provided for the passage of the aerosol precursor composition therethrough. The term "bottle" is meant to generally encompass any container having a wall and at least one opening. A tube or other conduit may be used for the passage of the aerosol precursor composition through the outside of the bottle and through the tube or other conduit. Such passage may also occur through capillary action. Alternatively, passive flow of liquid from the bottle may be controlled with an appropriate valve mechanism that can be opened to allow the flow of the aerosol precursor composition when the smoking article is in use and to prevent the flow of the aerosol precursor composition when the smoking article is not in use. Active flow mechanisms incorporating micropump devices are also contemplated for use in the present invention. Such containers may be formed from any suitable material that is substantially unreactive with any of the components of the aerosol precursor composition, such as glass, metal, low-porosity or non-porous ceramic, plastic, etc.

[0154] In some embodiments, the reservoir may be a woven or nonwoven fabric or another mass of fibers suitable for retaining the aerosol precursor composition (e.g., through absorption, adsorption, etc.) and allowing the precursor composition to escape for transport to the microheater. Such a reservoir layer may be formed from natural fibers, synthetic fibers, or combinations thereof. Non-limiting examples of useful materials include cotton, cellulose, polyester, polyamide, polylactic acid, combinations thereof, and the like. Similarly, the reservoir may be formed from ceramic, other porous materials, sintered materials, and the like. Smoking articles according to the present invention may include one reservoir or multiple reservoirs (e.g., two reservoirs, three reservoirs, four reservoirs, or more). As discussed herein, a reservoir may in effect be a substrate comprising one or more microheaters. Such a substrate may be formed from a porous material, such as those described above.

[0155] In certain embodiments, a wick may be used to transport one or more aerosol precursor compositions from a reservoir in a smoking article to a microheater. Thus, a wick for use in accordance with the present invention may be any material that provides sufficient wicking action to transport one or more components of the aerosol precursor composition to the microheater. Non-limiting examples include natural or synthetic fibers, such as cotton, cellulose, polyesters, polyamides, polylactic acids, glass fiber, combinations thereof, and the like. Other exemplary materials that may be used in wicks include metal ceramics and carbonized filaments (e.g., materials formed from carbonaceous materials that have undergone calcination to drive off non-carbon components of the material). Wicks may also be coated with substances that alter the capillary action of the fibers, and the fibers used to form the wick may have a particular cross-sectional shape or may be grooved to alter the capillary action of the fibers. The fibers used to form the wick may be provided individually, bundled, woven (including mesh and braid), or nonwoven. The porosity of the wick material may also be controlled to modify the capillary action of the wick, including controlling the average pore size and total porosity, controlling the wick geometry (or fiber geometry), and controlling the surface characteristics. Different wicks may also have different lengths. The term "wick" is also intended to encompass capillaries, and any combination of elements that provides the desired capillary action may be used.

[0156] The aerosol precursor composition utilized in the smoking article may be formed from a first component and at least a second individual component. Thus, the aerosol precursor composition may be formed from multiple components, e.g., two individual components, three individual components, four individual components, five individual components, etc. In some embodiments, the individual components of the aerosol precursor composition may be delivered separately to separate micro-heaters. Separate delivery, in this regard, may apply to each individual component of the aerosol precursor composition or to any combination of individual components. In some embodiments, two or more components of the aerosol precursor composition may be stored in the same reservoir and delivered separately to separate micro-heaters or to the same micro-heater. Various combinations of one or more reservoirs, one or more delivery elements, and one or more micro-heaters (all having various designs and formed from various materials) may be used to achieve controlled rates of delivery and heating of the components of the aerosol precursor composition.

[0157] Advantageously, by utilizing separate transport of the individual components of the aerosol precursor composition to separate heating elements, it may be possible to heat the individual components to different temperatures to obtain a more consistent aerosol for the user to inhale. While the aerosolization temperatures of the separate heaters are substantially the same, in some embodiments, the aerosolization temperatures of the separate heaters may differ by 2° C. or more, 5° C. or more, 10° C. or more, 20° C. or more, 30° C. or more, or 50° C. or more.

[0158] In addition to the foregoing, the control body and cartridge may be characterized by their overall length. For example, the control body may have a length of about 50 mm to about 110 mm, about 60 mm to about 100 mm, or about 65 mm to about 95 mm. The cartridge may have a length of about 20 mm to about 60 mm, about 25 mm to about 55 mm, or about 30 mm to about 50 mm. The overall length of the combined cartridge and control body (or the overall length of a smoking article of the present invention formed from a single, unitary shell) may be approximately equal to or less than the length of a typical cigarette (e.g., about 70 mm to about 130 mm, about 80 mm to about 125 mm, or about 90 mm to about 120 mm).

[0159] The cartridge and control body may be provided together as a complete smoking article, or generally as a drug delivery article, although the components may also be provided separately. For example, the present invention may also encompass a disposable unit for use with a reusable smoking article or a reusable drug delivery article.

[0160] In certain embodiments, a disposable unit or cartridge according to the present invention may be substantially identical to the cartridge described above with reference to the accompanying drawings. Thus, the disposable cartridge may comprise a substantially annular-shaped cartridge shell having a distal mating end configured for engaging a reusable smoking article or a drug delivery article and an opposing mouth end configured to permit the passage of formed vapor and any additional inhalable substance to a consumer. The cartridge shell may define an interior cartridge space that may contain additional cartridge components, particularly one or more micro-heaters.

[0161] Although the various figures described herein show the control body and cartridge in operative association, it is understood that the control body and cartridge may exist as separate devices, and therefore any discussion elsewhere herein regarding combined components should be understood to apply to the control body and cartridge as individual and separate components.

[0162] In another aspect, the present invention may relate to kits providing various components as described herein. For example, the kit may include a control body comprising one or more cartridges. The kit may further include a control body comprising one or more charging components. The kit may further include a control body comprising one or more batteries. The kit may further include a control body comprising one or more cartridges, one or more charging components, and / or one or more batteries. In further embodiments, the kit may include multiple cartridges. The kit may further include multiple cartridges, and one or more batteries and / or one or more charging components. The kits of the present invention may further include a case (or other packaging, carrying, or storage component) that fits one or more of the additional kit components. The case may be a reusable rigid or flexible container. Furthermore, the case may simply be a box or other packaging structure.

[0163] In a further embodiment, the present disclosure further includes a method of forming an aerosol in a smoking article. Specifically, the method may include initiating an electric current from a power source within the smoking article to a micro-heater of the smoking article, thereby heating the micro-heater, which heats the aerosol precursor composition.

[0164] In some embodiments, the smoking article utilized in this method may include multiple microheaters. Two or more microheaters may be heated simultaneously. Furthermore, the aerosol precursor composition may include two or more individual components, and the individual components of the aerosol precursor composition may be heated separately by simultaneously heated microheaters. More specifically, the simultaneously heated microheaters may receive current from a power source under different conditions, such that the microheaters are heated to different temperatures or for different periods of time. If desired, two or more microheaters may be heated sequentially (i.e., in a defined sequence or pattern).

[0165] In further embodiments of the method, the aerosol precursor composition may be coated on, adsorbed onto, or absorbed into a carrier material (i.e., a substrate), and the method may include inserting the carrier material into a smoking article before the step of activating an electric current. Similarly, a microheater may be attached to a substrate, and the method may include inserting the substrate into a smoking article before the step of activating an electric current. In certain embodiments, the aerosol precursor composition may be coated on a microheater attached to a substrate. In other embodiments, the method may include initiating a flow of the aerosol precursor composition from a reservoir to a chamber thermally coupled to the reservoir, thereby heating the aerosol precursor composition in the chamber.

[0166] Modifications and other embodiments of the present invention will occur to those skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. It is to be understood, therefore, that the present invention is not limited to the specific embodiments disclosed herein and that modifications and other embodiments are intended to be included within the scope of the appended claims. Certain terms used herein are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A smoking article comprising a power source and a micro-heater electrically connected to the power source.

2. 10. The smoking article of claim 1, wherein the micro-heater is a micro-electromechanical system (MEMS) based heater.

3. 10. The smoking article of claim 1, wherein the micro-heater is a thin film heater.

4. The smoking article of claim 1 , wherein the micro-heater comprises a patterned conductive material.

5. 5. The smoking article of claim 4, wherein the conductive material is selected from the group consisting of elemental metals, metal alloys, silicon, ceramics, carbon, carbides, nitrides, and combinations thereof.

6. 5. The smoking article of claim 4, wherein the micro-heater comprises a support layer having a conductive material patterned thereon.

7. 7. The smoking article of claim 6, wherein the conductive material is a printed layer laminated to the support layer, or the conductive material is an etched layer laminated to the support layer.

8. 5. The smoking article of claim 4, wherein the micro-heater comprises a protective layer overlying the patterned conductive material.

9. The smoking article according to any one of claims 6 to 8, wherein the support layer or the protective layer is temperature stable in the temperature range of about 125°C to about 750°C.

10. A smoking article according to any one of claims 6 to 8, wherein the support layer or protective layer comprises a silicon-based material.

11. 10. The smoking article of claim 1, wherein the micro-heater comprises two or more layers.

12. 10. The smoking article of claim 1, wherein the micro-heater comprises a conductive material sandwiched between two membranes.

13. 10. The smoking article of claim 1, wherein the micro-heater has a length of about 3 mm or less and a width of about 3 mm or less.

14. 10. The smoking article of claim 1, wherein the micro-heater has a length of about 0.5 mm to about 3 mm and a width of about 0.5 mm to about 3 mm.

15. The smoking article of claim 1 , wherein the micro-heater is attached to a substrate.

16. 16. The smoking article of claim 15, wherein the substrate is formed from an electrically insulating material.

17. The smoking article of claim 1 comprising a plurality of micro-heaters.

18. The smoking article of claim 1 , further comprising an aerosol precursor composition.

19. 20. The smoking article of claim 18, wherein the aerosol precursor composition is in the form of a liquid or gel at ambient conditions.

20. 20. The smoking article of claim 19, wherein the aerosol precursor composition is in a reservoir such that the aerosol precursor composition is spaced from the microheater.

21. 21. The smoking article of claim 20, wherein the article comprises a controller adapted to cause the microheater to deliver a predetermined amount of the aerosol precursor composition.

22. 21. The smoking article of claim 20, wherein the micro-heater is thermally coupled to a chamber adapted to receive a predetermined amount of the aerosol precursor composition through an opening in the chamber.

23. 23. A smoking article according to claim 22, wherein the chamber comprises an opening adapted for the exit of vapor from the chamber.

24. 23. The smoking article of claim 22, wherein the chamber has a volume of from about 0.2 ml to about 1 ml.

25. 20. The smoking article of claim 18, wherein the aerosol precursor composition is coated on, adsorbed onto, or absorbed into a carrier material, and the carrier material is positioned within the article so as to be in substantial contact with the micro-heater.

26. The smoking article of claim 1 , wherein the micro-heater is integral with an atomizer.

27. 27. The smoking article of claim 26, wherein the atomizer comprises a chamber defined by a wall, a cover, and a protective layer overlying the micro-heater.

28. 28. The smoking article of claim 27, wherein one or both of the wall and the cover include a plurality of apertures sized to allow vapor to pass through but not liquid.

29. A method for forming an aerosol in a smoking article, comprising passing an electric current from a power source within the smoking article through a micro-heater within the smoking article, thereby heating the micro-heater and an aerosol precursor composition in contact with the micro-heater.

30. 30. The method of claim 29, wherein the smoking article comprises a plurality of micro-heaters.

31. 30. The method of claim 29, wherein the aerosol precursor composition is coated on, adsorbed onto, or absorbed into a carrier material, and prior to the step of activating the electric current, the method further comprises inserting the carrier material into the smoking article.

32. 30. The method of claim 29, further comprising initiating a flow of the aerosol precursor composition from a reservoir to a chamber thermally coupled to the microheater, thereby heating the aerosol precursor composition in the chamber.

33. An atomizer suitable for use in an electronic smoking article, the atomizer comprising a chamber formed from a chamber wall, a cover, and a micro-heater.

34. 34. The atomizer of claim 33, wherein one or both of the chamber wall and the cover include a plurality of openings.

35. 35. The atomizer of claim 34, wherein one or more of the plurality of openings is sized to be permeable to vapor but not liquid.

Images